NSF Thread 6
From EM Drive
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Title: EM Drive Developments - related to space flight applications - Thread 6
Post by: rfmwguy on 12/11/2015 02:48 PM -
This is a thread - Thread 6 in the series - focused on objective analysis of whether the EM Drive (a cavity resonating at microwave frequencies) reported "thrust force" is an experimental artifact or whether it is a real propulsion effect that can be used for space applications, and if so, in discussing those possible space propulsion applications.
Objective skeptical inquiry is strongly welcome. Disagreements should be expressed politely, concentrating on the technical, engineering and scientific aspects, instead of focusing on people. As such, the use of experimental data, mathematics, physics, engineering, drawings, spreadsheets and computer simulations are strongly encouraged, while subjective wordy statements are discouraged. Peer-reviewed information from reputable journals is strongly encouraged. Please acknowledge the authors and respect copyrights.
Commercial advertisement is discouraged.
In order to minimize bandwidth and maximize information content, when quoting, one can use an ellipsis (...) to indicate the clipped material.
Only use the embed [img ]http://code when the image is small enough to fit within the page. Anything wider than the width of the page makes the page unreadable as it stretches it (we're working on auto reduction, but different browsers work different ways, etc.)
This link
http://math.typeit.org/
enables typing of mathematical symbols, including differentiation and integration, Greek letters, etc.
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Links to previous threads:
Thread 1:
http://forum.nasaspaceflight.com/index.php?topic=29276.0
Thread 2:
http://forum.nasaspaceflight.com/index.php?topic=36313.0
Thread 3:
http://forum.nasaspaceflight.com/index.php?topic=37642.0
Thread 4:
http://forum.nasaspaceflight.com/index.php?topic=38203.0
Thread 5:
http://forum.nasaspaceflight.com/index.php?topic=38577.0
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Entry level thread:
http://forum.nasaspaceflight.com/index.php?topic=37438.0
Baseline NSF Article:
http://www.nasaspaceflight.com/2015/04/evaluating-nasas-futuristic-em-drive/
This is the link to the EM Drive wiki that users are encouraged to contribute to, edit for accuracy, and build as a knowledge resource for the EM Drive:
http://emdrive.wiki
http://rfdriven.com
Chris note: Please note all posts need to be useful and worthwhile or they will be removed via moderation. This subject has large interest, with over 3.5 million thread reads and 850,000 article reads. Most people are reading and not posting, so when you post it is in front of a very large audience.
Also, and it should go without saying, amateur experiments are discouraged unless you have gained educated and/or professional advice for safety reasons.
(
)
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Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rfmwguy on 12/11/2015 02:51 PM -
Chris has removed the general moderator - by mutual agreement - for this section and assigned me, an EM Drive regular, as the new moderator.
However, unlike the general moderation of the overall forum, my role here is specific to EM Drive and my role is one of a caretaker.
My suggestions are to keep posts brief with current commentary on designs, builds, tests and theories. Its about as simple as that. Also, we should recognize this thread and the much larger NSF community is viewed by a large amount of people around the world. We should strive to be civil, respectful and relevant to the topics.
I look at these threads as an interactive RSS feed or news ticker on the EM Drive. People come here to read current news about designs, builds, tests and theories. It is not ideal for archiving data sets and there are a number of websites that have volunteered to do this.
Some could read any of my future posts on EM Drive as the ultimate authority, but I am not.
Have some fun and let's have at it.
- Dave (rfmwguy) -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: andygood on 12/11/2015 03:06 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1455933#msg1455933">Quote from: rfmwguy on 12/11/2015 02:51 PM</a>
Chris has removed the general moderator - by mutual agreement - for this section and assigned me, an EM Drive regular, as the new moderator.
- Dave (rfmwguy)
I, for one, welcome our new RF & microwave overlord! ;) -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/11/2015 03:08 PM -
Re: EM Drive Developments - related to space flight applications - Thread 5
« Reply #2538 on: Today at 02:54 PM »Quote from: ThereIWas3I did a little Googling and found that many meep users (not just here - everywhere) ran into the negative Q problem. It is an artifact of the way meep works, and is an indication that the simulation did not run long enough. Decreasing the bandwidth helps too.
After some other attempts, hunting around, I finally set BW to 0.015, set the center frequency to 2.4959 GHz where it wanted to resonate anyway, and increased the runtime by a factor of 1.25. (aero: I did this by increasing 'gc' from 8 to 10) Now I get a positive Q, that is closer to Rodal's earlier result. I got Q=99,938. Also absolute amplitude went up from 4.9 to 23.5. Error is 4.12E-7. Runtime was about 2 hours. Resonant frequncy came out 2.4959-1.248E-5i.
The equation I used for CU-D-conduct (which is the imaginary part of the relative complex permittivity (I should change the variable name) was posted earlier, -2*pi*2.4GHz*3.252698E+8i. That evaluates to -4.9083E+9. The "2.4GHz" term is actually in "meep units" so it is 2.4E+9 times 'a' divided by 'c'.
That's EXCELLENT work, @ThereIWas3, I also got Q's of ~90,000 using the exact solution for a (previous ?) geometry of the Shell Frustum (she has posted more than one geometrical shape for possible testing in the last year), depending on the input parameters (conductivity of copper, etc.).
Please let us know what mode shape is present in the EM Drive when you have a chance, or post some images of the fields when you have a chance.
It is great to have more people running Meep. Excellent work !
The MEEP input properties for the conductivity of copper ( MEEP:-2*pi*2.4GHz*3.252698E+8i) are very high, corresponding to a copper of practically 100% purity. Using impure copper, together with an imperfect geometry and surface reflectivity, will bring down the quality of resonance Q to a lower value in actual testing.
______
PS: Again: no negative mass/negative energy, no dark mass, no dark energy, no leaky fields, no strange quantum effects, no microwave black magic, were responsible for a negative Q. It was just a numerical artifact of the finite difference solution. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Star One on 12/11/2015 03:21 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1455940#msg1455940">Quote from: andygood on 12/11/2015 03:06 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1455933#msg1455933">Quote from: rfmwguy on 12/11/2015 02:51 PM</a>
Chris has removed the general moderator - by mutual agreement - for this section and assigned me, an EM Drive regular, as the new moderator.
- Dave (rfmwguy)
I, for one, welcome our new RF & microwave overlord! ;)
Seconded. Kind of biding my time at the moment over developments as I suspect that 2016 will bring a good degree of movement in that area. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: ThereIWas3 on 12/11/2015 03:29 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1455942#msg1455942">Quote from: Rodal on 12/11/2015 03:08 PM</a>
The MEEP input properties for the conductivity of copper ( MEEP:-2*pi*2.4GHz*3.252698E+8i) are very high, corresponding to a copper of practically 100% purity.
I think I got that number 3.252698E+8i from one of your own posts. I have looked around the web for reference materials on more realistic real-world values but have not found a good one yet. What units is that in? It does not look like Siemens/meter, which is 58.6E6 for Cu. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/11/2015 03:32 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1455948#msg1455948">Quote from: ThereIWas3 on 12/11/2015 03:29 PM</a>
The background of that number is in my previous posts, with luxury of details, including a discussion of units and a discussion of a conversion to usual units.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1455942#msg1455942">Quote from: Rodal on 12/11/2015 03:08 PM</a>The MEEP input properties for the conductivity of copper ( MEEP:-2*pi*2.4GHz*3.252698E+8i) are very high, corresponding to a copper of practically 100% purity.
I think I got that number 3.252698E+8i from one of your own posts. I have looked around the web for reference materials on more realistic real-world values but have not found a good one yet. What units is that in? It does not look like Siemens/meter, which is 58.6E6 for Cu.
My posts (as any user posts) can be searched by clicking on my NSF membership, and clicking "Show Posts"
For example (one of many posts on this subject):
http://forum.nasaspaceflight.com/index.php?topic=38577.msg1453316#msg1453316
Basically it is based on a model proposed, for pure copper, by @DeltaMass.
It corresponds to a conductivity in SI units of 4.342937 E+7
As I have explained in previous messages:
1) For other material conductivities you simply have to ratio this input by the material conductivities
2) The input to MEEP should be changed for different frequencies. The pure copper input is ONLY valid for 2.4 GHz. At other frequencies the input should be linearly ratioed by the frequency ratio, so that the conductivity stays constant
At resonating frequencies higher than 2.4 GHz, you should input a correspondingly LOWER number to keep the conductivity constant.
At lower frequencies than 2.4 GHz you should input a correspondingly HIGHER number, so that the conductivity stays at the correct constant value.
As I wrote in http://forum.nasaspaceflight.com/index.php?topic=38577.msg1453316#msg1453316:Quoteonly for f=2.4 E+09 Hertz one has
ε“/εo = 3.252698 E+08
while for f = 2.45 E+09 Hertz (for example) one has
ε“/εo = 3.186316 E+08Quote from: RodalThe conductivity in SI Units that corresponds to epsilon"=0.00288 is:
conductivity = omega * epsilon"
= 2 Pi frequency 0.00288
= 2 Pi 2.4E+9 * 0.00288
= 4.342937 E+7
which is almost 10 times smaller than 3.25E+8
Please also recall that DeltaMass was conscious that it is incorrect to take 0.00288 as a constant !
That value is a function of frequency.
What is approximately constant in this regime is the conductivity itself.
DeltaMass gave you explicit instructions to keep the conductivity constant, at other frequencies:
for example, the conductivity at 1 GHz is also 4.342937 E+7, so
at 1 GHz you should input into Meep (3.25...E+8 ) *2.4 = 7.8 E+8, for example
So, for pure Silver, for example (from the table in the link in your post),
Conductivity = 6.090E+07
So, instead of 3.25...E+8 for copper, you have to use ( 6.090E+07/4.342937 E+7 ) *3.25...E+8 at 2.4GHz
in other words, at 2.4 GHz, your input to Meep for pure Silver should be 1.402276 times higher than for the copper value given by DeltaMass. About 40% higher, whether in SI units or in Meep units.
In other words, everything else being the same, the quality of resonance (Q) should be about 40% higher with pure silver than with copper.
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Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SeeShells on 12/11/2015 03:33 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1455942#msg1455942">Quote from: Rodal on 12/11/2015 03:08 PM</a>
Re: EM Drive Developments - related to space flight applications - Thread 5
Top notch work to all!!!
« Reply #2538 on: Today at 02:54 PM »Quote from: ThereIWas3I did a little Googling and found that many meep users (not just here - everywhere) ran into the negative Q problem. It is an artifact of the way meep works, and is an indication that the simulation did not run long enough. Decreasing the bandwidth helps too.
After some other attempts, hunting around, I finally set BW to 0.015, set the center frequency to 2.4959 GHz where it wanted to resonate anyway, and increased the runtime by a factor of 1.25. (aero: I did this by increasing 'gc' from 8 to 10) Now I get a positive Q, that is closer to Rodal's earlier result. I got Q=99,938. Also absolute amplitude went up from 4.9 to 23.5. Error is 4.12E-7. Runtime was about 2 hours. Resonant frequncy came out 2.4959-1.248E-5i.
The equation I used for CU-D-conduct (which is the imaginary part of the relative complex permittivity (I should change the variable name) was posted earlier, -2*pi*2.4GHz*3.252698E+8i. That evaluates to -4.9083E+9. The "2.4GHz" term is actually in "meep units" so it is 2.4E+9 times 'a' divided by 'c'.
That's EXCELLENT work, @ThereIWas3, I also got Q's of ~90,000 using the exact solution for a (previous ?) geometry of the Shell Frustum (she has posted more than one geometrical shape for possible testing in the last year), depending on the input parameters (conductivity of copper, etc.).
Please let us know what mode shape is present in the EM Drive when you have a chance, or post some images of the fields when you have a chance.
It is great to have more people running Meep. Excellent work !
The MEEP input properties for the conductivity of copper ( MEEP:-2*pi*2.4GHz*3.252698E+8i) are very high, corresponding to a copper of practically 100% purity. Using impure copper, together with an imperfect geometry and surface reflectivity, will bring down the quality of resonance Q to a lower value in actual testing.
______
PS: Again: no negative mass/negative energy, no dark mass, no dark energy, no leaky fields, no strange quantum effects, no microwave black magic, were responsible for a negative Q. It was just a numerical artifact of the finite difference solution.
I am using the more costly O2 free copper.
https://www.onlinemetals.com/merchant.cfm?pid=15244&step=4&showunits=inches&id=966&top_cat=87
https://www.onlinemetals.com/productguides/copperguide.cfm
Also the waveguides and the endplates are electroplated with silver which will bring up the Q just a little.
Shell -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/11/2015 05:12 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1455949#msg1455949">Quote from: Rodal on 12/11/2015 03:32 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1455948#msg1455948">Quote from: ThereIWas3 on 12/11/2015 03:29 PM</a>
The background of that number is in my previous posts, with luxury of details, including a discussion of units and a discussion of a conversion to usual units.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1455942#msg1455942">Quote from: Rodal on 12/11/2015 03:08 PM</a>The MEEP input properties for the conductivity of copper ( MEEP:-2*pi*2.4GHz*3.252698E+8i) are very high, corresponding to a copper of practically 100% purity.
I think I got that number 3.252698E+8i from one of your own posts. I have looked around the web for reference materials on more realistic real-world values but have not found a good one yet. What units is that in? It does not look like Siemens/meter, which is 58.6E6 for Cu.
My posts (as any user posts) can be searched by clicking on my NSF membership, and clicking "Show Posts"
For example (one of many posts on this subject):
http://forum.nasaspaceflight.com/index.php?topic=38577.msg1453316#msg1453316
Basically it is based on a model proposed, for pure copper, by @DeltaMass.
It corresponds to a conductivity in SI units of 4.342937 E+7
As I have explained in previous messages:
1) For other material conductivities you simply have to ratio this input by the material conductivities
2) The input to MEEP should be changed for different frequencies. The pure copper input is ONLY valid for 2.4 GHz. At other frequencies the input should be linearly ratioed by the frequency ratio, so that the conductivity stays constant
At resonating frequencies higher than 2.4 GHz, you should input a correspondingly LOWER number to keep the conductivity constant.
At lower frequencies than 2.4 GHz you should input a correspondingly HIGHER number, so that the conductivity stays at the correct constant value.
As I wrote in http://forum.nasaspaceflight.com/index.php?topic=38577.msg1453316#msg1453316:Quoteonly for f=2.4 E+09 Hertz one has
ε“/εo = 3.252698 E+08
while for f = 2.45 E+09 Hertz (for example) one has
ε“/εo = 3.186316 E+08Quote from: RodalThe conductivity in SI Units that corresponds to epsilon"=0.00288 is:
conductivity = omega * epsilon"
= 2 Pi frequency 0.00288
= 2 Pi 2.4E+9 * 0.00288
= 4.342937 E+7
which is almost 10 times smaller than 3.25E+8
Please also recall that DeltaMass was conscious that it is incorrect to take 0.00288 as a constant !
That value is a function of frequency.
What is approximately constant in this regime is the conductivity itself.
DeltaMass gave you explicit instructions to keep the conductivity constant, at other frequencies:
for example, the conductivity at 1 GHz is also 4.342937 E+7, so
at 1 GHz you should input into Meep (3.25...E+8 ) *2.4 = 7.8 E+8, for example
So, for pure Silver, for example (from the table in the link in your post),
Conductivity = 6.090E+07
So, instead of 3.25...E+8 for copper, you have to use ( 6.090E+07/4.342937 E+7 ) *3.25...E+8 at 2.4GHz
in other words, at 2.4 GHz, your input to Meep for pure Silver should be 1.402276 times higher than for the copper value given by DeltaMass. About 40% higher, whether in SI units or in Meep units.
In other words, everything else being the same, the quality of resonance (Q) should be about 40% higher with pure silver than with copper.
OK, as an example, let's calculate some numbers:
1) Since the resonant frequency you calculated was 2.4959 GHz instead of 2.4 GHz, the input instead of 3.252698 E+08 should have been:
(2.4/2.4959)*3.252698 E+08 = 3.127719 E+08
Therefore, your MEEP run's output quality of resonance Q instead of Q=99,938, would have been, at 2.4959 GHz, for DeltaMass pure copper:
Q = (2.4/2.4959)*99,938
= 96,098
__________________________________________
2) If instead of copper's conductivity, as proposed by DeltaMass, you would have used the value for conductivity for Bronze, Commercial (Annealed) in (http://eddy-current.com/conductivity-of-metals-sorted-by-resistivity/): 2.552E+07, the Q output would have been:
Q = (2.4/2.4959)*99,938*(2.552E+07)/(4.342937 E+7)
=56,469
and the Meep input should have been:
(2.4/2.4959)*((2.552E+07)/(4.342937 E+7))*3.252698 E+08 = 1.837912 E+08
instead of 3.252698E+8
__________________________________________
3) If instead of copper's conductivity, as proposed by DeltaMass, you would have used the value for conductivity for Pure Silver in (http://eddy-current.com/conductivity-of-metals-sorted-by-resistivity/): 6.090E+07, the Q output would have been:
Q = (2.4/2.4959)*99,938*(6.090E+07)/(4.342937 E+7)
=134,756
and the Meep input should have been:
(2.4/2.4959)*((6.090E+07)/(4.342937 E+7))*3.252698 E+08 = 4.385928 E+08
instead of 3.252698E+8
__________________________________________
NOTE: See http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456018#msg1456018
(Radio-frequency) investigations have shown that the conductivity of much of the commercial silver-plating is about half of that of pure copper
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Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: OnlyMe on 12/11/2015 05:35 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1455988#msg1455988">Quote from: Rodal on 12/11/2015 05:12 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1455949#msg1455949">Quote from: Rodal on 12/11/2015 03:32 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1455948#msg1455948">Quote from: ThereIWas3 on 12/11/2015 03:29 PM</a>
The background of that number is in my previous posts, with luxury of details, including a discussion of units and a discussion of a conversion to usual units.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1455942#msg1455942">Quote from: Rodal on 12/11/2015 03:08 PM</a>The MEEP input properties for the conductivity of copper ( MEEP:-2*pi*2.4GHz*3.252698E+8i) are very high, corresponding to a copper of practically 100% purity.
I think I got that number 3.252698E+8i from one of your own posts. I have looked around the web for reference materials on more realistic real-world values but have not found a good one yet. What units is that in? It does not look like Siemens/meter, which is 58.6E6 for Cu.
My posts (as any user posts) can be searched by clicking on my NSF membership, and clicking "Show Posts"
For example (one of many posts on this subject):
http://forum.nasaspaceflight.com/index.php?topic=38577.msg1453316#msg1453316
Basically it is based on a model proposed, for pure copper, by @DeltaMass.
It corresponds to a conductivity in SI units of 4.342937 E+7
As I have explained in previous messages:
1) For other material conductivities you simply have to ratio this input by the material conductivities
2) The input to MEEP should be changed for different frequencies. The pure copper input is ONLY valid for 2.4 GHz. At other frequencies the input should be linearly ratioed by the frequency ratio, so that the conductivity stays constant
At resonating frequencies higher than 2.4 GHz, you should input a correspondingly LOWER number to keep the conductivity constant.
At lower frequencies than 2.4 GHz you should input a correspondingly HIGHER number, so that the conductivity stays at the correct constant value.
As I wrote in http://forum.nasaspaceflight.com/index.php?topic=38577.msg1453316#msg1453316:Quoteonly for f=2.4 E+09 Hertz one has
ε“/εo = 3.252698 E+08
while for f = 2.45 E+09 Hertz (for example) one has
ε“/εo = 3.186316 E+08Quote from: RodalThe conductivity in SI Units that corresponds to epsilon"=0.00288 is:
conductivity = omega * epsilon"
= 2 Pi frequency 0.00288
= 2 Pi 2.4E+9 * 0.00288
= 4.342937 E+7
which is almost 10 times smaller than 3.25E+8
Please also recall that DeltaMass was conscious that it is incorrect to take 0.00288 as a constant !
That value is a function of frequency.
What is approximately constant in this regime is the conductivity itself.
DeltaMass gave you explicit instructions to keep the conductivity constant, at other frequencies:
for example, the conductivity at 1 GHz is also 4.342937 E+7, so
at 1 GHz you should input into Meep (3.25...E+8 ) *2.4 = 7.8 E+8, for example
So, for pure Silver, for example (from the table in the link in your post),
Conductivity = 6.090E+07
So, instead of 3.25...E+8 for copper, you have to use ( 6.090E+07/4.342937 E+7 ) *3.25...E+8 at 2.4GHz
in other words, at 2.4 GHz, your input to Meep for pure Silver should be 1.402276 times higher than for the copper value given by DeltaMass. About 40% higher, whether in SI units or in Meep units.
In other words, everything else being the same, the quality of resonance (Q) should be about 40% higher with pure silver than with copper.
OK, as an example, let's calculate some numbers:
1) Since the resonant frequency you calculated was 2.4959 GHz instead of 2.4 GHz, the input instead of 3.252698 E+08 should have been:
(2.4/2.4959)*3.252698 E+08 = 3.127719 E+08
Therefore, your MEEP run's output quality of resonance Q instead of Q=99,938, would have been, at 2.4959 GHz, for DeltaMass pure copper:
Q = (2.4/2.4959)*99,938
= 96,098
__________________________________________
2) If instead of copper's conductivity, as proposed by DeltaMass, you would have used the value for conductivity for Bronze, Commercial (Annealed) in (http://eddy-current.com/conductivity-of-metals-sorted-by-resistivity/): 2.552E+07, the Q output would have been:
Q = (2.4/2.4959)*99,938*(2.552E+07)/(4.342937 E+7)
=56,469
and the input should have been:
(2.4/2.4959)*((2.552E+07)/(4.342937 E+7))*3.252698 E+08 = 1.837912 E+08
__________________________________________
3) If instead of copper's conductivity, as proposed by DeltaMass, you would have used the value for conductivity for Pure Silver in (http://eddy-current.com/conductivity-of-metals-sorted-by-resistivity/): 6.090E+07, the Q output would have been:
Q = (2.4/2.4959)*99,938*(6.090E+07)/(4.342937 E+7)
=134,756
and the input should have been:
(2.4/2.4959)*((6.090E+07)/(4.342937 E+7))*3.252698 E+08 =
How thick would the silver plating (over copper) need to be, to model the frustum as pure silver? And how might a thin plating of gold, to protect the silver plating affect things? -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/11/2015 05:37 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1455995#msg1455995">Quote from: OnlyMe on 12/11/2015 05:35 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1455988#msg1455988">Quote from: Rodal on 12/11/2015 05:12 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1455949#msg1455949">Quote from: Rodal on 12/11/2015 03:32 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1455948#msg1455948">Quote from: ThereIWas3 on 12/11/2015 03:29 PM</a>
The background of that number is in my previous posts, with luxury of details, including a discussion of units and a discussion of a conversion to usual units.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1455942#msg1455942">Quote from: Rodal on 12/11/2015 03:08 PM</a>The MEEP input properties for the conductivity of copper ( MEEP:-2*pi*2.4GHz*3.252698E+8i) are very high, corresponding to a copper of practically 100% purity.
I think I got that number 3.252698E+8i from one of your own posts. I have looked around the web for reference materials on more realistic real-world values but have not found a good one yet. What units is that in? It does not look like Siemens/meter, which is 58.6E6 for Cu.
My posts (as any user posts) can be searched by clicking on my NSF membership, and clicking "Show Posts"
For example (one of many posts on this subject):
http://forum.nasaspaceflight.com/index.php?topic=38577.msg1453316#msg1453316
Basically it is based on a model proposed, for pure copper, by @DeltaMass.
It corresponds to a conductivity in SI units of 4.342937 E+7
As I have explained in previous messages:
1) For other material conductivities you simply have to ratio this input by the material conductivities
2) The input to MEEP should be changed for different frequencies. The pure copper input is ONLY valid for 2.4 GHz. At other frequencies the input should be linearly ratioed by the frequency ratio, so that the conductivity stays constant
At resonating frequencies higher than 2.4 GHz, you should input a correspondingly LOWER number to keep the conductivity constant.
At lower frequencies than 2.4 GHz you should input a correspondingly HIGHER number, so that the conductivity stays at the correct constant value.
As I wrote in http://forum.nasaspaceflight.com/index.php?topic=38577.msg1453316#msg1453316:Quoteonly for f=2.4 E+09 Hertz one has
ε“/εo = 3.252698 E+08
while for f = 2.45 E+09 Hertz (for example) one has
ε“/εo = 3.186316 E+08Quote from: RodalThe conductivity in SI Units that corresponds to epsilon"=0.00288 is:
conductivity = omega * epsilon"
= 2 Pi frequency 0.00288
= 2 Pi 2.4E+9 * 0.00288
= 4.342937 E+7
which is almost 10 times smaller than 3.25E+8
Please also recall that DeltaMass was conscious that it is incorrect to take 0.00288 as a constant !
That value is a function of frequency.
What is approximately constant in this regime is the conductivity itself.
DeltaMass gave you explicit instructions to keep the conductivity constant, at other frequencies:
for example, the conductivity at 1 GHz is also 4.342937 E+7, so
at 1 GHz you should input into Meep (3.25...E+8 ) *2.4 = 7.8 E+8, for example
So, for pure Silver, for example (from the table in the link in your post),
Conductivity = 6.090E+07
So, instead of 3.25...E+8 for copper, you have to use ( 6.090E+07/4.342937 E+7 ) *3.25...E+8 at 2.4GHz
in other words, at 2.4 GHz, your input to Meep for pure Silver should be 1.402276 times higher than for the copper value given by DeltaMass. About 40% higher, whether in SI units or in Meep units.
In other words, everything else being the same, the quality of resonance (Q) should be about 40% higher with pure silver than with copper.
OK, as an example, let's calculate some numbers:
1) Since the resonant frequency you calculated was 2.4959 GHz instead of 2.4 GHz, the input instead of 3.252698 E+08 should have been:
(2.4/2.4959)*3.252698 E+08 = 3.127719 E+08
Therefore, your MEEP run's output quality of resonance Q instead of Q=99,938, would have been, at 2.4959 GHz, for DeltaMass pure copper:
Q = (2.4/2.4959)*99,938
= 96,098
__________________________________________
2) If instead of copper's conductivity, as proposed by DeltaMass, you would have used the value for conductivity for Bronze, Commercial (Annealed) in (http://eddy-current.com/conductivity-of-metals-sorted-by-resistivity/): 2.552E+07, the Q output would have been:
Q = (2.4/2.4959)*99,938*(2.552E+07)/(4.342937 E+7)
=56,469
and the input should have been:
(2.4/2.4959)*((2.552E+07)/(4.342937 E+7))*3.252698 E+08 = 1.837912 E+08
__________________________________________
3) If instead of copper's conductivity, as proposed by DeltaMass, you would have used the value for conductivity for Pure Silver in (http://eddy-current.com/conductivity-of-metals-sorted-by-resistivity/): 6.090E+07, the Q output would have been:
Q = (2.4/2.4959)*99,938*(6.090E+07)/(4.342937 E+7)
=134,756
and the input should have been:
(2.4/2.4959)*((6.090E+07)/(4.342937 E+7))*3.252698 E+08 =
How thick would the silver plating (over) need to be, to model the frustum as pure silver? And how might a thin playing of gold, to protect the silver plating affect things?
It would need to be thicker than the skin depth for Silver at 2.4959 GHz, which is:
1.291 micrometers = 50.82 microinches
______________
Pure gold, according to http://eddy-current.com/conductivity-of-metals-sorted-by-resistivity/, has a conductivity of 4.060E+07, which is less than Silver's 6.090E+07 and less than DeltaMass assumed conductivity for pure copper 4.342937 E+7
(Pure Silver Eddy Current Technology Incorporated)/(Pure copper DeltaMass) = 1.402
(Pure Gold Eddy Current Technology Incorporated)/(Pure copper DeltaMass) = 0.935
______________
So, for highest quality of resonance Q, best thing is Pure Silver, by far. Followed by Pure Copper and Pure Gold which are close to each other.
The advantage of Gold is that it does not corrode or stain, its disadvantage is ... price :)
Gold is the least reactive of all metals and is benign in all natural and industrial environments. Gold never reacts with oxygen (one of the most active elements), which means it will not rust or tarnish -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SeeShells on 12/11/2015 05:51 PM -
Ref long thread... http://forum.nasaspaceflight.com/index.php?topic=39004.msg1455988#msg1455988
From what I've read I'm around 40-50 um and may put another coat but I don't think it's needed as RF penetration is under 5um.
I think I'll keep silver for now.
1) it develops oxides quite slowly (takes sulfur around it) and it also cleans very easy.
2) To lay down a electroplated uniform layer of gold that remains under 1um is very hard to do with a hand method and it will need to wait for a professional plating shop specializing in waveguides.
Shell
modded, Stupiddd speeeling korector -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: ThereIWas3 on 12/11/2015 06:01 PM -
I will correct the computation of permittivity to use the actual signal frequency rather than the fixed 2.4 GHz it is now. I am trying to eliminate "magic constants" in the code as much as possible, so everything automatically tracks the input model data.
Edit: meep does not do well at simulating very thin layers, unless you set the lattice size really small, which increases computation time enormously. So I would keep the current thickish material specification and set the permitivity somewhere between Cu and Ag. The current thickness is greater than real life for the same reason. We do not need to simulate the escape of fields outside for the current purposes. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SteveD on 12/11/2015 06:04 PM - Stupid question: how does a spacecraft propelled by an EMDrive (if it works) slow down? The basic answer is by creating a force in the opposite direction. What happens to the energy that the drive has been loading into the spaceship? It can't simply be destroyed, it has to go somewhere. Where?
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: OnlyMe on 12/11/2015 06:07 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456002#msg1456002">Quote from: SeeShells on 12/11/2015 05:51 PM</a>
Ref long thread... http://forum.nasaspaceflight.com/index.php?topic=39004.msg1455988#msg1455988
From what I've read I'm around 40-50 um and may put another coat but I don't think it's needed as RF penetration is under 5um.
I think I'll keep silver for now.
1) it develops oxides quite slowly (takes sulfur around it) and it also cleans very easy.
2) To lay down a electroplated uniform layer of gold that remains under 1um is very hard to do with a hand method and it will need to wait for a professional plating shop specializing in waveguides.
Shell
modded, Stupiddd speeeling korector
I don't think from the information above, that gold plating would be worthwhile, funtionally or cost wise, as far as a test design is concerned. It would be good to know if silver electroplating can be modeled as pure silver or if it needs to be adjusted in some way. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: OnlyMe on 12/11/2015 06:14 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456011#msg1456011">Quote from: SteveD on 12/11/2015 06:04 PM</a>
Stupid question: how does a spacecraft propelled by an EMDrive (if it works) slow down? The basic answer is by creating a force in the opposite direction. What happens to the energy that the drive has been loading into the spaceship? It can't simply be destroyed, it has to go somewhere. Where?
Actually assuming that the EMDrive or another EMDrive on the same satellite is used for deceleration, wouldn't that amount to conservation of momentum, just over an extended time frame... Acceleration and deceleration both generated by a closed box thruster.
Aside from that, since unsing a constant thrust device of any kind would involve far different trajectories, some of the thrust would dissipated in overcoming gravitation.., but that leads back to the conservation of momentum issue -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/11/2015 06:18 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456012#msg1456012">Quote from: OnlyMe on 12/11/2015 06:07 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456002#msg1456002">Quote from: SeeShells on 12/11/2015 05:51 PM</a>
Ref long thread... http://forum.nasaspaceflight.com/index.php?topic=39004.msg1455988#msg1455988
From what I've read I'm around 40-50 um and may put another coat but I don't think it's needed as RF penetration is under 5um.
I think I'll keep silver for now.
1) it develops oxides quite slowly (takes sulfur around it) and it also cleans very easy.
2) To lay down a electroplated uniform layer of gold that remains under 1um is very hard to do with a hand method and it will need to wait for a professional plating shop specializing in waveguides.
Shell
modded, Stupiddd speeeling korector
I don't think from the information above, that gold plating would be worthwhile, funtionally or cost wise, as far as a test design is concerned. It would be good to know if silver electroplating can be modeled as pure silver or if it needs to be adjusted in some way.
That's correct, electroplating is detrimental to conductivity when compared to pure copper, to the point that rather than increasing the Q, electroplating silver may actually decrease Q drastically, by up to 50% according to this peer-reviewed article:
"It is often found that silver-plating a copper conductor increases the radio-frequency losses (reduces Q) instead of reducing them as expected"
(Radio-frequency) investigations have shown that the conductivity of much of the commercial silver-plating is about half of that of pure copper
So that silver-plating, rather than increasing the Q by 40%, according to this classic paper, apparently will reduce Q to half of the Q with pure copper
Radio Frequency Performance of Electro Plated Finishes
A.M. Fowler
Proceedings IREE Australia May 1970
http://k6mhe.com/n7ws/Plating.pdf
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: X_RaY on 12/11/2015 06:23 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456011#msg1456011">Quote from: SteveD on 12/11/2015 06:04 PM</a>
Stupid question: how does a spacecraft propelled by an EMDrive (if it works) slow down? The basic answer is by creating a force in the opposite direction. What happens to the energy that the drive has been loading into the spaceship? It can't simply be destroyed, it has to go somewhere. Where?
1. Yes turn the ship or the device by 180° what is generating the thrust to slow down.
2. The device have to generate thrust... Some work has to be done to slow the ship done, this will generate some heat/ thermal radiation. All of this will increase the entropy of the universe... such as in the acceleration case. There isn't a difference between the acceleration and the deceleration phase. Acceleration and the deceleration are equal in the light of Relativity.
https://en.wikipedia.org/wiki/Work_%28physics%29
https://en.wikipedia.org/wiki/Entropy
3. Conservation of energy is one of the fundamental statements of modern physics, energy don't will destroyed. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: aero on 12/11/2015 06:33 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456008#msg1456008">Quote from: ThereIWas3 on 12/11/2015 06:01 PM</a>
I will correct the computation of permittivity to use the actual signal frequency rather than the fixed 2.4 GHz it is now. I am trying to eliminate "magic constants" in the code as much as possible, so everything automatically tracks the input model data.
Please make a backup copy of your model before you refine it so that we can be sure to reconcile our models. The Shells model you are using was much different than mine, but I have made a model of what I think you are running. If the attached looks like what you have, I will run it with your input data to verify our models. I don't recall whether or not it is similar to the model that Dr. Rodal worked with. Maybe he does.
Edit: meep does not do well at simulating very thin layers, unless you set the lattice size really small, which increases computation time enormously. So I would keep the current thickish material specification and set the permitivity somewhere between Cu and Ag. The current thickness is greater than real life for the same reason. We do not need to simulate the escape of fields outside for the current purposes.
Edit add: Oh, and I suggest that you change your coordinate system to use the z-coordinate as the axis of rotation. I used x at the time the NSF-1701 model was uploaded but it did cause confusion among our physicists friends. That's why I changed it to the generally accepted convention that holds z as the direction of propagation of EM waves. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/11/2015 06:37 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456008#msg1456008">Quote from: ThereIWas3 on 12/11/2015 06:01 PM</a>
I will correct the computation of permittivity to use the actual signal frequency rather than the fixed 2.4 GHz it is now. I am trying to eliminate "magic constants" in the code as much as possible, so everything automatically tracks the input model data.
Edit: meep does not do well at simulating very thin layers, unless you set the lattice size really small, which increases computation time enormously. So I would keep the current thickish material specification and set the permitivity somewhere between Cu and Ag. The current thickness is greater than real life for the same reason. We do not need to simulate the escape of fields outside for the current purposes.
I agree, it does not make any sense (from a numerical solution viewpoint) to attempt to simulate with Meep the thin layer, at the same time that one is simulating the cavity. Incompatible meshing size, leading to numerical instability upon solution of the simultaneous equations. To simulate the thin layers would need to write a new separate code to couple the solution in the layer to the solution in the cavity, in order to eliminate the numerical instability that would unsue otherwise from trying to solve it within Meep in a single mesh.
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: zen-in on 12/11/2015 07:16 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456018#msg1456018">Quote from: Rodal on 12/11/2015 06:18 PM</a>
...
That's correct, electroplating is detrimental to conductivity when compared to pure copper, to the point that rather than increasing the Q, electroplating silver may actually decrease Q drastically, by up to 50% according to this peer-reviewed article:
"It is often found that silver-plating a copper conductor increases the radio-frequency losses (reduces Q) instead of reducing them as expected"
(Radio-frequency) investigations have shown that the conductivity of much of the commercial silver-plating is about half of that of pure copper
So that silver-plating, rather than increasing the Q by 40%, according to this classic paper, apparently will reduce Q to half of the Q with pure copper
Radio Frequency Performance of Electro Plated Finishes
A.M. Fowler
Proceedings IREE Australia May 1970
http://k6mhe.com/n7ws/Plating.pdf
I think a lot depends on how the Silver electroplate is done. The hobbyist brush method likely puts a porus coat of Silver down so it's conductivity would be reduced. I have only done Silver plating with a Silver Cyanide solution which may be unobtanium now. When the Silver plate sets it is a flat white color and I suspect that surface is also porus to a degree. Microwave cavities all seem to be made from brass and then are Silver plated. The companies that make these filters must be doing something to improve the surface conductivity of the Silver plate. I don't know if the home hobbiest can improve Silver plate to where its conductivity is better than Copper. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SteveD on 12/11/2015 07:34 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456020#msg1456020">Quote from: X_RaY on 12/11/2015 06:23 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456011#msg1456011">Quote from: SteveD on 12/11/2015 06:04 PM</a>
Stupid question: how does a spacecraft propelled by an EMDrive (if it works) slow down? The basic answer is by creating a force in the opposite direction. What happens to the energy that the drive has been loading into the spaceship? It can't simply be destroyed, it has to go somewhere. Where?
1. Yes turn the ship or the device by 180° what is generating the thrust to slow down.
2. The device have to generate thrust... Some work has to be done to slow the ship done, this will generate some heat/ thermal radiation. All of this will increase the entropy of the universe... such as in the acceleration case. There isn't a difference between the acceleration and the deceleration phase. Acceleration and the deceleration are equal in the light of Relativity.
https://en.wikipedia.org/wiki/Work_%28physics%29
https://en.wikipedia.org/wiki/Entropy
3. Conservation of energy is one of the fundamental statements of modern physics, energy don't will destroyed.
Seems like that's only rephrasing the question in formalized terms.QuoteIn thermodynamics, entropy (usual symbol S) is a measure of the number of specific realizations or microstates which may realize a thermodynamic system in a defined state specified by macroscopic observables. Entropy is commonly understood as a measure of disorder. According to the second law of thermodynamics the entropy of an isolated system never decreases; such a system will spontaneously proceed towards thermodynamic equilibrium, the configuration with maximum entropy. Systems that are not isolated may decrease in entropy, provided they increase the entropy of their environment by at least that same amount. Since entropy is a state function, the change in the entropy of a system is the same for any process that goes from a given initial state to a given final state, whether the process is reversible or irreversible. However, irreversible processes increase the combined entropy of the system and its environment.
A sealed box on a spaceship would seem like an isolated system. How is it increasing universal entropy as a way to shed energy and slow down? -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: R.W. Keyes on 12/11/2015 07:56 PM -
How important are computational resources in emdrive development? How much can be gained by more MEEP installations? What if we had some sort of web-based job management system for a distributed, volunteer computation system? I'd want to start simply, and not spread one job on multiple systems, but rather, have some sort of gatekeeper and dispatcher between emdrive developers and others who would donate computational time.
A few months ago, there was conversation about doing simulations on GPUs, which MEEP doesn't currently support, but there is a similar program for CUDA called B-CALM. Did anything ever come of this? Do we have some port of the MEEP simulation codes to B-CALM?
I don't want to go to the cloud for this, I want to take advantage of currently underutilized resources, specifically for emdrive development purposes. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SeeShells on 12/11/2015 07:59 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456041#msg1456041">Quote from: zen-in on 12/11/2015 07:16 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456018#msg1456018">Quote from: Rodal on 12/11/2015 06:18 PM</a>
...
That's correct, electroplating is detrimental to conductivity when compared to pure copper, to the point that rather than increasing the Q, electroplating silver may actually decrease Q drastically, by up to 50% according to this peer-reviewed article:
"It is often found that silver-plating a copper conductor increases the radio-frequency losses (reduces Q) instead of reducing them as expected"
(Radio-frequency) investigations have shown that the conductivity of much of the commercial silver-plating is about half of that of pure copper
So that silver-plating, rather than increasing the Q by 40%, according to this classic paper, apparently will reduce Q to half of the Q with pure copper
Radio Frequency Performance of Electro Plated Finishes
A.M. Fowler
Proceedings IREE Australia May 1970
http://k6mhe.com/n7ws/Plating.pdf
I think a lot epends on how the Silver electroplate is done. The hobbyist brush method likely puts a porus coat of Silver down so it's conductivity would be reduced. I have only done Silver plating with a Silver Cyanide solution which may be unobtanium now. When the Silver plate sets it is a flat white color and I suspect that surface is also porus to a degree. Microwave cavities all seem to be made from brass and then are Silver plated. The companies that make these filters must be doing something to improve the surface conductivity of the Silver plate. However for home hobbiest it is moot.
Ok you presented something that should be worried about if anyone is going to silver plate at home or even as a prototype in a lab.
This is how I addressed those concerns in the paper.
CasWell electroplating soultion lays down a 99.9% pure silver layer, no brighteners or any other additives.
Using the little wand they give you is very slow and very tedious and will only do a couple of microns per minute. The bottom of the frustum is sealed so I filled it with ~3-4 inches of plating fluid and used a Stainless Steel 316 rod that was ~ 3/8" or 10mm and inserted it into the captured bath. Slowly moved it around about 30-40mm from the bottom for a hour.
This gave a very thick 40-50 um electroplated silver coating. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: OnlyMe on 12/11/2015 07:59 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456046#msg1456046">Quote from: SteveD on 12/11/2015 07:34 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456020#msg1456020">Quote from: X_RaY on 12/11/2015 06:23 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456011#msg1456011">Quote from: SteveD on 12/11/2015 06:04 PM</a>
Stupid question: how does a spacecraft propelled by an EMDrive (if it works) slow down? The basic answer is by creating a force in the opposite direction. What happens to the energy that the drive has been loading into the spaceship? It can't simply be destroyed, it has to go somewhere. Where?
1. Yes turn the ship or the device by 180° what is generating the thrust to slow down.
2. The device have to generate thrust... Some work has to be done to slow the ship done, this will generate some heat/ thermal radiation. All of this will increase the entropy of the universe... such as in the acceleration case. There isn't a difference between the acceleration and the deceleration phase. Acceleration and the deceleration are equal in the light of Relativity.
https://en.wikipedia.org/wiki/Work_%28physics%29
https://en.wikipedia.org/wiki/Entropy
3. Conservation of energy is one of the fundamental statements of modern physics, energy don't will destroyed.
Seems like that's only rephrasing the question in formalized terms.QuoteIn thermodynamics, entropy (usual symbol S) is a measure of the number of specific realizations or microstates which may realize a thermodynamic system in a defined state specified by macroscopic observables. Entropy is commonly understood as a measure of disorder. According to the second law of thermodynamics the entropy of an isolated system never decreases; such a system will spontaneously proceed towards thermodynamic equilibrium, the configuration with maximum entropy. Systems that are not isolated may decrease in entropy, provided they increase the entropy of their environment by at least that same amount. Since entropy is a state function, the change in the entropy of a system is the same for any process that goes from a given initial state to a given final state, whether the process is reversible or irreversible. However, irreversible processes increase the combined entropy of the system and its environment.
A sealed box on a spaceship would seem like an isolated system. How is it increasing universal entropy as a way to shed energy and slow down?
The box is not entirely sealed relative to the exterior environment. Microwaves are being pumped in.
The problem is that everything we know about microwaves says the net forces on the inside walls should be zero. If the box does produce thrust unrelated to heat dissipation etc..., and we set aside any quantum vacuum speculations, there would have to be something new in the way the resonance of the microwaves inside the box interact with the walls that results in an asymmetric transfer of momentum.
Strictly speaking if what is happening is just a transfer of momentum from the microwaves to the frustum, while it would be something we have not seen before and thus new physics, it should not involve a violation of conservation of momentum until and unless the thrust produced out paces the energy pumped in...
First thing is reproduce the claims of thrust and then as many here have been saying all along meticulously account for all heat and magnetic/electromagnetic related affects... In the DIY builders domain, that really means a need for probably double or triple digit mN of force.., and repeatability. Preferably with an independent copy of the build.
EDIT - Something else that has been bothering me, is that if this is a direct transfer of momentum from microwaves to the frustum.., it seems to me that the frustum being grounded might be required. There has to be some kind of loop that may not be reproducible in space... Unless just grounding back to power supply is sufficient. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: X_RaY on 12/11/2015 08:00 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456046#msg1456046">Quote from: SteveD on 12/11/2015 07:34 PM</a>
In fact it is part of a closed system namely the universe. The device interats with the space around.(Complete isolated systems are not present at all since the total range of EM fields as well as G fields is unlimeted per definition)<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456020#msg1456020">Quote from: X_RaY on 12/11/2015 06:23 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456011#msg1456011">Quote from: SteveD on 12/11/2015 06:04 PM</a>Stupid question: how does a spacecraft propelled by an EMDrive (if it works) slow down? The basic answer is by creating a force in the opposite direction. What happens to the energy that the drive has been loading into the spaceship? It can't simply be destroyed, it has to go somewhere. Where?
1. Yes turn the ship or the device by 180° what is generating the thrust to slow down.
2. The device have to generate thrust... Some work has to be done to slow the ship done, this will generate some heat/ thermal radiation. All of this will increase the entropy of the universe... such as in the acceleration case. There isn't a difference between the acceleration and the deceleration phase. Acceleration and the deceleration are equal in the light of Relativity.
https://en.wikipedia.org/wiki/Work_%28physics%29
https://en.wikipedia.org/wiki/Entropy
3. Conservation of energy is one of the fundamental statements of modern physics, energy don't will destroyed.
Seems like that's only rephrasing the question in formalized terms.QuoteIn thermodynamics, entropy (usual symbol S) is a measure of the number of specific realizations or microstates which may realize a thermodynamic system in a defined state specified by macroscopic observables. Entropy is commonly understood as a measure of disorder. According to the second law of thermodynamics the entropy of an isolated system never decreases; such a system will spontaneously proceed towards thermodynamic equilibrium, the configuration with maximum entropy. Systems that are not isolated may decrease in entropy, provided they increase the entropy of their environment by at least that same amount. Since entropy is a state function, the change in the entropy of a system is the same for any process that goes from a given initial state to a given final state, whether the process is reversible or irreversible. However, irreversible processes increase the combined entropy of the system and its environment.
A sealed box on a spaceship would seem like an isolated system. How is it increasing universal entropy as a way to shed energy and slow down?
Microwave energie will heat the resonant cavity caused by the ohmic losses. The cavity will radiate in the IR spectrum also at its outer side.. Even if it is installed on a ship, the radiation will heating the ship. The ship radiates the thermal energy into the free space around it.
This process is irreversible. You can use a part of the heat to generate electrical energy but never all of it. I think its impossible to create a "perpetuum mobile" or any kind of "free energy harvesting machine". ;)
If the EM Drive works one need to put energy into it. Till now there is no closed and accepted theory that explains the observed thrust. As far as we know the HF to kinetic energy conversion is really bad, the biggest part of the energy will converted into heat.
And again, acceleration and deceleration (negative acceleration, sign is used per human agreement/convention in relation to the total speed of a second object like a planet) are equal. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: glennfish on 12/11/2015 08:11 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456053#msg1456053">Quote from: R.W. Keyes on 12/11/2015 07:56 PM</a>
How important are computational resources in emdrive development? How much can be gained by more MEEP installations? What if we had some sort of web-based job management system for a distributed, volunteer computation system? I'd want to start simply, and not spread one job on multiple systems, but rather, have some sort of gatekeeper and dispatcher between emdrive developers and others who would donate computational time.
A few months ago, there was conversation about doing simulations on GPUs, which MEEP doesn't currently support, but there is a similar program for CUDA called B-CALM. Did anything ever come of this? Do we have some port of the MEEP simulation codes to B-CALM?
I don't want to go to the cloud for this, I want to take advantage of currently underutilized resources, specifically for emdrive development purposes.
IMHO either not very or not much.
My thinking is that the only computational model that's being worked with at present is MEEP on the assumption that high Q is key to whatever is going on. To that end, those who need MEEP have it either in a linux box or a vmware linux emulator. It's slow slow slow, but it works.
However, if at some point there's a positive signal that won't go away, and the physics community agrees that it's real, then there would be a strong desire to characterize why it's there, and a need to build a simulator that matched real world results. If MEEP is still relevant at that point, then there would be a need for speed, and perhaps serious parallel processing efforts.
On the other hand, a positive signal that doesn't go away might have no design relationship to MEEP, since it probably wouldn't be something you could calculate with EM codes like MEEP. The new code EMEEP would evolve either through experiments that tie down the parameters, or a yet to be agreed upon theory as to what it should be simulating. How those calculations would be done is in the TBD domain. If things get there, let's collaborate on building an EMEEP engine. :) -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: zen-in on 12/11/2015 08:39 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456055#msg1456055">Quote from: SeeShells on 12/11/2015 07:59 PM</a>
...
Ok you presented something that should be worried about if anyone is going to silver plate at home or even as a prototype in a lab.
This is how I addressed those concerns in the paper.
CasWell electroplating soultion lays down a 99.9% pure silver layer, no brighteners or any other additives.
Using the little wand they give you is very slow and very tedious and will only do a couple of microns per minute. The bottom of the frustum is sealed so I filled it with ~3-4 inches of plating fluid and used a Stainless Steel 316 rod that was ~ 3/8" or 10mm and inserted it into the captured bath. Slowly moved it around about 30-40mm from the bottom for a hour.
This gave a very thick 40-50 um electroplated silver coating.
The one alternative for those who want the absolute best Q possible is to use Silver fill Copper. This is Copper with a thin (1 mil or less) layer of Fine Silver that is bonded to the Copper using a hot roll process. I haven't seen it available in large sheets though. The plating solution you are using is probably safe to use. I doubt it contains any cyanide. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Notsosureofit on 12/11/2015 08:53 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456058#msg1456058">Quote from: X_RaY on 12/11/2015 08:00 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456046#msg1456046">Quote from: SteveD on 12/11/2015 07:34 PM</a>
In fact it is part of a closed system namely the universe. The device interats with the space around.(Complete isolated systems are not present at all since the total range of EM fields as well as G fields is unlimeted per definition)<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456020#msg1456020">Quote from: X_RaY on 12/11/2015 06:23 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456011#msg1456011">Quote from: SteveD on 12/11/2015 06:04 PM</a>Stupid question: how does a spacecraft propelled by an EMDrive (if it works) slow down? The basic answer is by creating a force in the opposite direction. What happens to the energy that the drive has been loading into the spaceship? It can't simply be destroyed, it has to go somewhere. Where?
1. Yes turn the ship or the device by 180° what is generating the thrust to slow down.
2. The device have to generate thrust... Some work has to be done to slow the ship done, this will generate some heat/ thermal radiation. All of this will increase the entropy of the universe... such as in the acceleration case. There isn't a difference between the acceleration and the deceleration phase. Acceleration and the deceleration are equal in the light of Relativity.
https://en.wikipedia.org/wiki/Work_%28physics%29
https://en.wikipedia.org/wiki/Entropy
3. Conservation of energy is one of the fundamental statements of modern physics, energy don't will destroyed.
Seems like that's only rephrasing the question in formalized terms.QuoteIn thermodynamics, entropy (usual symbol S) is a measure of the number of specific realizations or microstates which may realize a thermodynamic system in a defined state specified by macroscopic observables. Entropy is commonly understood as a measure of disorder. According to the second law of thermodynamics the entropy of an isolated system never decreases; such a system will spontaneously proceed towards thermodynamic equilibrium, the configuration with maximum entropy. Systems that are not isolated may decrease in entropy, provided they increase the entropy of their environment by at least that same amount. Since entropy is a state function, the change in the entropy of a system is the same for any process that goes from a given initial state to a given final state, whether the process is reversible or irreversible. However, irreversible processes increase the combined entropy of the system and its environment.
A sealed box on a spaceship would seem like an isolated system. How is it increasing universal entropy as a way to shed energy and slow down?
Microwave energie will heat the resonant cavity caused by the ohmic losses. The cavity will radiate in the IR spectrum also at its outer side.. Even if it is installed on a ship, the radiation will heating the ship. The ship radiates the thermal energy into the free space around it.
This process is irreversible. You can use a part of the heat to generate electrical energy but never all of it. I think its impossible to create a "perpetuum mobile" or any kind of "free energy harvesting machine". ;)
If the EM Drive works one need to put energy into it. Till now there is no closed and accepted theory that explains the observed thrust. As far as we know the HF to kinetic energy conversion is really bad, the biggest part of the energy will converted into heat.
And again, acceleration and deceleration (negative acceleration, sign is used per human agreement/convention in relation to the total speed of a second object like a planet) are equal.
...or if you like the Sachs/Schwebel GR versions...into gravitational currents.
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: R.W. Keyes on 12/11/2015 09:03 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456064#msg1456064">Quote from: glennfish on 12/11/2015 08:11 PM</a>
OK. I've got a core i5 3470 3.2 ghz w/ 32gb of ram, running Debian. I don't know what's common in this community but I think of it as a decently fast machine, and want to do useful things with it while I am asleep.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456053#msg1456053">Quote from: R.W. Keyes on 12/11/2015 07:56 PM</a>How important are computational resources in emdrive development? How much can be gained by more MEEP installations? What if we had some sort of web-based job management system for a distributed, volunteer computation system? I'd want to start simply, and not spread one job on multiple systems, but rather, have some sort of gatekeeper and dispatcher between emdrive developers and others who would donate computational time.
A few months ago, there was conversation about doing simulations on GPUs, which MEEP doesn't currently support, but there is a similar program for CUDA called B-CALM. Did anything ever come of this? Do we have some port of the MEEP simulation codes to B-CALM?
I don't want to go to the cloud for this, I want to take advantage of currently underutilized resources, specifically for emdrive development purposes.
IMHO either not very or not much.
My thinking is that the only computational model that's being worked with at present is MEEP on the assumption that high Q is key to whatever is going on. To that end, those who need MEEP have it either in a linux box or a vmware linux emulator. It's slow slow slow, but it works.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456064#msg1456064">Quote from: glennfish on 12/11/2015 08:11 PM</a>However, if at some point there's a positive signal that won't go away, and the physics community agrees that it's real, then there would be a strong desire to characterize why it's there, and a need to build a simulator that matched real world results. If MEEP is still relevant at that point, then there would be a need for speed, and perhaps serious parallel processing efforts.
I am looking forward to that. Until I can actually equip a lab (funds are coming...someday), running simulations is about the only useful thing I can do.
On the other hand, a positive signal that doesn't go away might have no design relationship to MEEP, since it probably wouldn't be something you could calculate with EM codes like MEEP. The new code EMEEP would evolve either through experiments that tie down the parameters, or a yet to be agreed upon theory as to what it should be simulating. How those calculations would be done is in the TBD domain. If things get there, let's collaborate on building an EMEEP engine. :) -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SeeShells on 12/11/2015 09:14 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456076#msg1456076">Quote from: zen-in on 12/11/2015 08:39 PM</a>
Details<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456055#msg1456055">Quote from: SeeShells on 12/11/2015 07:59 PM</a>
...
Ok you presented something that should be worried about if anyone is going to silver plate at home or even as a prototype in a lab.
This is how I addressed those concerns in the paper.
CasWell electroplating soultion lays down a 99.9% pure silver layer, no brighteners or any other additives.
Using the little wand they give you is very slow and very tedious and will only do a couple of microns per minute. The bottom of the frustum is sealed so I filled it with ~3-4 inches of plating fluid and used a Stainless Steel 316 rod that was ~ 3/8" or 10mm and inserted it into the captured bath. Slowly moved it around about 30-40mm from the bottom for a hour.
This gave a very thick 40-50 um electroplated silver coating.
The one alternative for those who want the absolute best Q possible is to use Silver fill Copper. This is Copper with a thin (1 mil or less) layer of Fine Silver that is bonded to the Copper using a hot roll process. I haven't seen it available in large sheets though. The plating solution you are using is probably safe to use. I doubt it contains any cyanide.
Before I did this I wanted to make sure there wasn't any cyanide and I don't even think you can get that stuff anymore.
http://www.caswellplating.com/electroplating-anodizing/silver-plating-kits/silver-brush-plating-solution-1-pint.html
(Caswell Silver is a new type of alkaline cyanide free silver plating solution that will plate over nickel, sterling silver, gold, rhodium, copper, brass and bronze. The system will provide uniform color consistency and even coverage.)
Needed to prevent this...
X X
^
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: ThereIWas3 on 12/11/2015 09:40 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456023#msg1456023">Quote from: aero on 12/11/2015 06:33 PM</a>
Please make a backup copy of your model before you refine it so that we can be sure to reconcile our models.
It is all kept in a github repository that tracks every change and from which every past version can be recalled. I have been doing software development for 40 years and you quickly learn not to make the mistake of having only one copy.QuoteThe Shells model you are using was much different than mine, but I have made a model of what I think you are running. If the attached looks like what you have, I will run it with your input data to verify our models. I don't recall whether or not it is similar to the model that Dr. Rodal worked with. Maybe he does.
The dimension numbers I was using came directly from SeeShells herself, very recently. I have not done any image generation runs with it yet. That will come next.
QuoteEdit add: Oh, and I suggest that you change your coordinate system to use the z-coordinate as the axis of rotation. I used x at the time the NSF-1701 model was uploaded but it did cause confusion among our physicists friends. That's why I changed it to the generally accepted convention that holds z as the direction of propagation of EM waves.
Yes, I saw the comment about that in the code. I will change that so everyone follows the same convention.
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: glennfish on 12/11/2015 09:46 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456083#msg1456083">Quote from: R.W. Keyes on 12/11/2015 09:03 PM</a>
OK. I've got a core i5 3470 3.2 ghz w/ 32gb of ram, running Debian. I don't know what's common in this community but I think of it as a decently fast machine, and want to do useful things with it while I am asleep.
That's a sweet box. Uncommon in most home based communities.
ALL. This person is offering, I believe, MEEP processing services for this community. With those specs he can probably knock the socks off of any home PC and trim processing times.
Unless some of you folks are "borrowing" your boxes from your employers, this looks like a sweet offer. I'd recommend you PM him if you want to shave some time.
Gimme data, I'll give you stats.
Give him a problem, he'll give you a simulation.
At least that's how I read it. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: ThereIWas3 on 12/11/2015 09:51 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456064#msg1456064">Quote from: glennfish on 12/11/2015 08:11 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456053#msg1456053">Quote from: R.W. Keyes on 12/11/2015 07:56 PM</a>
How important are computational resources in emdrive development? How much can be gained by more MEEP installations?
...
However, if at some point there's a positive signal that won't go away, and the physics community agrees that it's real, then there would be a strong desire to characterize why it's there, and a need to build a simulator that matched real world results.
...
If the effect turns out to be real, I expect universities with supercomputers to fall all over themselves wanting to work on this. My own school has one. (https://www.osc.edu/supercomputing/hpc)
I see the contribution of simulation being in visualizing what is actually going on inside the frustrum, which leads toward a theory of why the thing works (if it works at all). The various DIY experimentors are working on does it work. Existing published results each present their own theory as to how it works, but I do not find any of them convincing. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: AG4D on 12/11/2015 10:15 PM -
Hi everyone
Sorry for this incursion, but do you think to use three magnetrons is better than one. And perhaps to refresh at -25° your EMdrive before dynamique test is better too ?
For example, dynamique test during ten seconds, to -25° at 100° ? -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SeeShells on 12/11/2015 10:24 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456111#msg1456111">Quote from: ThereIWas3 on 12/11/2015 09:51 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456064#msg1456064">Quote from: glennfish on 12/11/2015 08:11 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456053#msg1456053">Quote from: R.W. Keyes on 12/11/2015 07:56 PM</a>
How important are computational resources in emdrive development? How much can be gained by more MEEP installations?
...
However, if at some point there's a positive signal that won't go away, and the physics community agrees that it's real, then there would be a strong desire to characterize why it's there, and a need to build a simulator that matched real world results.
...
If the effect turns out to be real, I expect universities with supercomputers to fall all over themselves wanting to work on this. My own school has one. (https://www.osc.edu/supercomputing/hpc)
I see the contribution of simulation being in visualizing what is actually going on inside the frustrum, which leads toward a theory of why the thing works (if it works at all). The various DIY experimentors are working on does it work. Existing published results each present their own theory as to how it works, but I do not find any of them convincing.
Data, we need data. without data the theories are just theories and subject to hammering from the physics crowd. EagleWorks believes there is a anomalous thrust remaining even after quantifying any errors or other sources that could qualify as thrust. They have a peer paper being reviewed and you can bet it's going to be a very very rigorous review.
I don't have the heavy physics math to do a paper but I will provide data. This process is going to take sometime, but I hope in some small way to add to the growing plus side that there is thrust. Like EagleWorks I'm slowly going over absolutely everything and retesting, rerunning.
Hang in there, good data takes time.
Shell -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: ThereIWas3 on 12/11/2015 10:44 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456113#msg1456113">Quote from: AG4D on 12/11/2015 10:15 PM</a>
Hi everyone
Sorry for this incursion, but do you think to use three magnetrons is better than one.
My thought is it would be worse. There is little chance of keeping multiple magnetrons phase locked with each other in these types of setups. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: aero on 12/11/2015 11:48 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456128#msg1456128">Quote from: ThereIWas3 on 12/11/2015 10:44 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456113#msg1456113">Quote from: AG4D on 12/11/2015 10:15 PM</a>
Hi everyone
Sorry for this incursion, but do you think to use three magnetrons is better than one.
My thought is it would be worse. There is little chance of keeping multiple magnetrons phase locked with each other in these types of setups.
Yes, I know that Shell's gave you the numbers, I saw the post. I was just remarking that I needed to make that model in order to run comparisons. Which I have done, but the model I imaged and posted does not resonate at all with Hz excitation. What EM component or components did you use to excite your antenna?
Meep will calculate a different Q for each of the 6 EM components.
Oh, and if you insert this - (at-end output-hfield-y) right before your harminv statement, you can see what the fields look like. Actually you can do as much output there as you like, except that you need to know how many cycles the job will run in order to output time slices. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SteveD on 12/12/2015 12:40 AM -
Hi all. Busy, got to run, but got something stuck in my head.
The entropy of an isolated system cannot decrease.
Isn't Q factor a measure of entropy? I mean the classic definition is the number of cycles of a pendulum per unit of energy.
An EmDrive would seem like an isolated system.
But some of these simulations are suggesting the modes are unstable. Don't some of these simulations show instability even with a narrowband feed? If a mode fell apart -- lower Q -- and then another mode developed -- higher Q -- (or simply two modes of differing Qs fluctuated) that that would seem like a system moving to a higher degree of order. Which suggests the system is not isolated. For that matter, if you could redshift photons, couldn't you setup a situation where the photons where just above a resonant frequency and would be redshifted down into it (meaning that order would increase).
Or am I saying something wrong here. The first two things that come to mind are that 1. the redshift example would simply reflect a situation where the device hasn't reached a stable energy level yet (but isn't that what Shawyer is doing by injecting energy in bursts - completing whatever is going on before a stable energy level is reached). 2. Could the movement to a higher Q be reflected in heat feeding back into the external rf feed -- making the system not isolated (or perhaps its with heat exchange to the outside).
But I still can't help thinking that there might be some way to use fluctuation in Q or in the modes to show a decrease in entropy proving that a sealed tin can isn't a closed system -- its just exhausting into the QV, gravitational waves, or [insert your favorite theory here]. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Prunesquallor on 12/12/2015 01:10 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456011#msg1456011">Quote from: SteveD on 12/11/2015 06:04 PM</a>
Stupid question: how does a spacecraft propelled by an EMDrive (if it works) slow down? The basic answer is by creating a force in the opposite direction. What happens to the energy that the drive has been loading into the spaceship? It can't simply be destroyed, it has to go somewhere. Where?
Weeeelll, assuming a simplified interpretation of EMDrive thrust, you simply thrust in the opposite direction as the spacecraft's velocity vector.
Energy generally isn't "loaded" in this context. The EM Drive (theoretically) converts stored energy (e.g., from fissile material in a nuclear reactor) or external energy (e.g., solar) into kinetic energy. However, as we have debated ad nauseum, it leads to a paradox if you assume an EM Drive provides constant thrust at constant power with no propellant consumption. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: LasJayhawk on 12/12/2015 02:27 AM -
If a quantum tunneling diode can exhibit negative resistance, perhaps a quantum tunneling drive could exhibit negative Q? MEEP might be trying to tell us something.
My theory ( stolen from John Quick )
"Basically, the only new principle involved is that instead of power being generated by the relative motion of conductors and fluxes, it is produced by the modial interaction of magneto-reluctance and capacitive directance." ;D -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Kenjee on 12/12/2015 02:49 AM -
I wondered how fluids react in frustum so I did this just for fun.
This is non-scientific CGI fluid dynamics simulation.
https://vid.me/GYoK (https://vid.me/GYoK)
The Eye of Sauron :)
(SeeShells Dimensions) -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: ThereIWas3 on 12/12/2015 02:55 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456148#msg1456148">Quote from: aero on 12/11/2015 11:48 PM</a>
What EM component or components did you use to excite your antenna?
I don't think I changed any of that from the original NSF-1701.ctl file, other than changing the distance from the end to 55mm as you suggested.; Antenna is a half-wave dipole, 55mm from the small end.<br>; from the small end. The actual device injects with a coaxial feedline<br>; on the side.<br>(set! antSIx 0.055)<br>(set! antSIy 0)<br>(set! antSIz 0) <br>(set! antlongx 0) ; direction vector of dipole antenna SI units<br>(set! antlongy 0.058) ; Halfwave dipole is about 61 mm<br>(set! antlongz 0)<br>
And the source:(define drivesrc-Gaus (list <br>(make source (src (make gaussian-src (frequency fmeep) (fwidth BW) ))<br> (component Ez) <br> (center antx anty antz)<br> (size antsizex antsizey antsizez)<br> (axis axex axey axez) ) ; Components - Ex, Ey, Ez or Hx, Hy, Hz<br>))<br>
This is still with the original axes, X being the centerline.
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: ThereIWas3 on 12/12/2015 03:05 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1455949#msg1455949">Quote from: Rodal on 12/11/2015 03:32 PM</a>
The pure copper input is ONLY valid for 2.4 GHz. At other frequencies the input should be linearly ratioed by the frequency ratio, so that the conductivity stays constant. At resonating frequencies higher than 2.4 GHz, you should input a correspondingly LOWER number to keep the conductivity constant.
I changed the formula for permittivity to scale it by (2.4GHz/InputFreq), so as the frequency goes up, the permittivity goes down from its 2.4GHz reference value. With an input frequency of 2.4959 GHz, this shifted the Q only a small amount, from 99938 to 99943, but now that is one less thing to worry about for future cases. That change is down in the noise as far as I am concerned, for this particular case. (This is still with the 100% pure definition for Cu.) -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: VAXHeadroom on 12/12/2015 03:05 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456011#msg1456011">Quote from: SteveD on 12/11/2015 06:04 PM</a>
Stupid question: how does a spacecraft propelled by an EMDrive (if it works) slow down? The basic answer is by creating a force in the opposite direction. What happens to the energy that the drive has been loading into the spaceship? It can't simply be destroyed, it has to go somewhere. Where?
In practice a spacecraft only has Delta-V thrusters mounted in one direction anyway, so you just turn it around and jet the other way to slow down. How do you turn around? Using your tinyEM Drive attitude control thrusters mounted at oblique angles to the center of mass of course! ;) -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: aero on 12/12/2015 03:13 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456195#msg1456195">Quote from: ThereIWas3 on 12/12/2015 02:55 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456148#msg1456148">Quote from: aero on 12/11/2015 11:48 PM</a>
What EM component or components did you use to excite your antenna?
I don't think I changed any of that from the original NSF-1701.ctl file, other than changing the distance from the end to 55mm as you suggested.; Antenna is a half-wave dipole, 55mm from the small end.<br>; from the small end. The actual device injects with a coaxial feedline<br>; on the side.<br>(set! antSIx 0.055)<br>(set! antSIy 0)<br>(set! antSIz 0) <br>(set! antlongx 0) ; direction vector of dipole antenna SI units<br>(set! antlongy 0.058) ; Halfwave dipole is about 61 mm<br>(set! antlongz 0)<br>
And the source:(define drivesrc-Gaus (list <br>(make source (src (make gaussian-src (frequency fmeep) (fwidth BW) ))<br> (component Ez) <br> (center antx anty antz)<br> (size antsizex antsizey antsizez)<br> (axis axex axey axez) ) ; Components - Ex, Ey, Ez or Hx, Hy, Hz<br>))<br>
This is still with the original axes, X being the centerline.
Hmm - something strange is going on here. I just completed that run using Ez excitation and got nothing again. But this time the fields were formed, not like the Hz excitation which was just noise. See attached
I've been starting with your solution - I'll open the bandwidth and chase it down for my model. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SeeShells on 12/12/2015 03:23 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456199#msg1456199">Quote from: aero on 12/12/2015 03:13 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456195#msg1456195">Quote from: ThereIWas3 on 12/12/2015 02:55 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456148#msg1456148">Quote from: aero on 12/11/2015 11:48 PM</a>
What EM component or components did you use to excite your antenna?
I don't think I changed any of that from the original NSF-1701.ctl file, other than changing the distance from the end to 55mm as you suggested.; Antenna is a half-wave dipole, 55mm from the small end.<br>; from the small end. The actual device injects with a coaxial feedline<br>; on the side.<br>(set! antSIx 0.055)<br>(set! antSIy 0)<br>(set! antSIz 0) <br>(set! antlongx 0) ; direction vector of dipole antenna SI units<br>(set! antlongy 0.058) ; Halfwave dipole is about 61 mm<br>(set! antlongz 0)<br>
And the source:(define drivesrc-Gaus (list <br>(make source (src (make gaussian-src (frequency fmeep) (fwidth BW) ))<br> (component Ez) <br> (center antx anty antz)<br> (size antsizex antsizey antsizez)<br> (axis axex axey axez) ) ; Components - Ex, Ey, Ez or Hx, Hy, Hz<br>))<br>
This is still with the original axes, X being the centerline.
Hmm - something strange is going on here. I just completed that run using Ez excitation and got nothing again. But this time the fields were formed, not like the Hz excitation which was just noise. See attached
Do a 1/4 wave dipole. 1/4 Wl 30.36mm -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SeeShells on 12/12/2015 04:53 AM -
Named for its discoverer, who, 55 years ago, was trying to understand why fluids like mayonnaise move so slowly.
The Casimir effect some have been relating to the QV effects is related to work with Mayonnaise?
http://apod.nasa.gov/apod/ap151206.html -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: oliverio on 12/12/2015 08:19 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456221#msg1456221">Quote from: SeeShells on 12/12/2015 04:53 AM</a>
Named for its discoverer, who, 55 years ago, was trying to understand why fluids like mayonnaise move so slowly.
The Casimir effect some have been relating to the QV effects is related to work with Mayonnaise?
http://apod.nasa.gov/apod/ap151206.html
At the very least, the Casimir effect demonstrates the analytical possibility of Dr. White's theory. We could understand the EMdrive as a far-field high-energy asymmetric analogue to the Casimir effect. (One of my previous posts points to a peer-reviewed paper demonstrating just such an a asymmetric system; a single accelerated mirror radiates photons in a vacuum because [according to the Casimir effect] it is reflecting virtual photons it passes through while accelerating.) -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: OnlyMe on 12/12/2015 12:54 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456243#msg1456243">Quote from: oliverio on 12/12/2015 08:19 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456221#msg1456221">Quote from: SeeShells on 12/12/2015 04:53 AM</a>
Named for its discoverer, who, 55 years ago, was trying to understand why fluids like mayonnaise move so slowly.
The Casimir effect some have been relating to the QV effects is related to work with Mayonnaise?
http://apod.nasa.gov/apod/ap151206.html
At the very least, the Casimir effect demonstrates the analytical possibility of Dr. White's theory. We could understand the EMdrive as a far-field high-energy asymmetric analogue to the Casimir effect. (One of my previous posts points to a peer-reviewed paper demonstrating just such an a asymmetric system; a single accelerated mirror radiates photons in a vacuum because [according to the Casimir effect] it is reflecting virtual photons it passes through while accelerating.)
I don't believe this is what is happening with the EMDrive. In a simplistic way what the dynamical Casimir effect is suggesting is that the momentum of a relativistic mirror adds sufficient energy to the EM ground state of the vacuum to generate photons. The virtual photons in the most accepted concept of the quantum vacuum, which would be immutable or static, (because there is no real consensus), are just a minimal EM field potential.., no momentum until or unless they interact with a moving object and even then most theorists require the object to be accelerating. Even in Haisch's theory of inertia which tends to lead toward a dynamic or mutable ground state originating in a Machian manner, the background potential of the quantum vacuum remains isotropic from inertial frames, becoming anisotropic from an accelerating frame.
The one case immediately apparent departing from this is the Casimir effect but it requires two closely located uncharged conducting plates...
Whatever is going on with the EMDrive, it seems far more likely that the dynamics of the boundary conditions inside the drive, together with an asymmetry in the microwave field density, leads to a asymmetry in the transfer of momentum between the microwaves and the frustum. The issue of relativistic velocities from a constant classical thrust resulting in free energy, is a special relativity problem that should wait until we have some proof that relativistic velocities are even possible.
Once a build with a significant thrust is repeatable, very close evaluations of the heat signatures/losses relative to power in must be carried out. I am unsure some of that work could be accomplished by DIYs but then they have already done things I would have never thought they could. It seems there has been some suggestion that a close match of frequency in to resonance and perhaps pulsing the on/off cycle properly, reduces the heat build up and increases the thrust. If this is true it may be a balancing act that improves the amount of EM energy momentum transfer...
Whatever is happening it is new physics, but that does not mean it involves a violation of conservation of momentum as has been argued repeatedly. You have energy going in, in the form of microwaves and energy coming out as heat and kinetic energy or thrust/added momentum.
Something else that has bothered me about the quantum vacuum virtual particle speculations, is that the quantum field fluctuations that are being referred to as virtual particles can not from anything I have read, flow through a solid mass of matter. They would interact with the object, so a virtual particle thruster would have to then be interacting with the vacuum outside the frustum by essentially repelling or pushing off of those quantum field fluctuations. How this could be generated by something we have to believe is originating inside of the frustum is difficult...
And this all assumes that Eagleworks silence pending peer review and Shell's silence while she is double checking..., both suggests a confirmation of thrust. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: ThereIWas3 on 12/12/2015 12:57 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456199#msg1456199">Quote from: aero on 12/12/2015 03:13 AM</a>
Hmm - something strange is going on here. I just completed that run using Ez excitation and got nothing again. But this time the fields were formed, not like the Hz excitation which was just noise. See attached
I've been starting with your solution - I'll open the bandwidth and chase it down for my model.
Don't forget the other changes I mentioned earlier (http://forum.nasaspaceflight.com/index.php?topic=38577.msg1455937#msg1455937): BW=0.015 and gc=10
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Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rfmwguy on 12/12/2015 01:32 PM -
Well done! <a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456192#msg1456192">Quote from: Kenjee on 12/12/2015 02:49 AM</a>
I wondered how fluids react in frustum so I did this just for fun.
This is non-scientific CGI fluid dynamics simulation.
https://vid.me/GYoK (https://vid.me/GYoK)
The Eye of Sauron :)
(SeeShells Dimensions) -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: ThereIWas3 on 12/12/2015 01:51 PM -
If you look up "Luminiferous Aether (https://en.wikipedia.org/wiki/Luminiferous_aether)" you find some interesting things.
While the Michelson–Morley experiment (https://en.wikipedia.org/wiki/Michelson%E2%80%93Morley_experiment) did not prove that the "Aether" existed, neither did it prove that it did not exist, because Einstein came up with an explanation (the theory of relativity) for observations about the transmission of light that did not require the existence of an Aether to work. And furthermore, that the MM experiment could not have detected the Aether even if it did exist.
On that same Wiki page, if you scroll down to follow the link to Aether Therories (https://en.wikipedia.org/wiki/Aether_theories) you see a collection of other explanations as to what this "aether" might be. Among those listed is Quantum Vacuum (https://en.wikipedia.org/wiki/Aether_theories#Quantum_vacuum)!
Maybe MM's experiment could not have detected it, but the EmDrive effect can? -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: ThereIWas3 on 12/12/2015 02:09 PM -
Earlier SeeShells askedQuote
(Meepers, do we have the sidewalls correct and are we sure we are not leaking RF, if we don't use the tune chamber for the different tune points TE012 and TE013 and we just extend the Se top plate will leave a large gap.)
The meep model we are using does not actuallly model the end plates and walls separately, so it is continuous. The description is actually of two solid cones, one inside the other. The larger cone is made of copper, and the slightly smaller inner cone is made of "air". This is the way the meep documentation says to model things like waveguides, though in that case the lengths are infinite. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: glennfish on 12/12/2015 02:18 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456188#msg1456188">Quote from: LasJayhawk on 12/12/2015 02:27 AM</a>
If a quantum tunneling diode can exhibit negative resistance, perhaps a quantum tunneling drive could exhibit negative Q? MEEP might be trying to tell us something.
My theory ( stolen from John Quick )
"Basically, the only new principle involved is that instead of power being generated by the relative motion of conductors and fluxes, it is produced by the modial interaction of magneto-reluctance and capacitive directance." ;D
Negative resistance is not "passive" in the sense that getting more power out than in, happens with such a circuit. There is always an additional source of power which provides amplification which in the circuit results in negative R at one specific circuit element.
My guess is you could create a result that exhibited a negative Q, since Q can be formulated as a function of resistance, and if you can make R negative, you can make Q negative, however, it doesn't look to me like it would be anything new, novel, or fundamental to the Q calculations done here.
To me, it looks like an amplifier put in a circuit to make the sign flip for one component. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rfmwguy on 12/12/2015 03:28 PM - Couple of posts removed per request of staff...no biggie...carry on whilst I visit family in indy and follow some cool design thoughts here...negative meep thing peaked my non-meep brain
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Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: ThereIWas3 on 12/12/2015 03:40 PM - The negative Q values are a known artifact of the computational model used inside meep under certain conditions. It has nothing to do with physics.
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Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/12/2015 03:55 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456308#msg1456308">Quote from: ThereIWas3 on 12/12/2015 03:40 PM</a>
The negative Q values are a known artifact of the computational model used inside meep under certain conditions. It has nothing to do with physics.
Correct. It has nothing to do with physics.
It has nothing to do with reality.
Discussing this is similar to previous discussions incorrectly attaching physical significance to:
previous Meep models which included a Finite Difference mesh outside the EM Drive, which showed numerical magnitudes of the electromagnetic fields to be 24 orders of magnitude smaller than the fields inside the EM Drive. People (unfamiliar with numerical methods like Finite Difference solutions) were unaware that such numerical methods entail the solution of simultaneous equations and therefore that the magnitude of the fields outside the EM Drive instead of displaying a perfect zero will routinely display very small numbers (sometimes negative) associated with the numerical precision and ill-conditioning of inversion of matrices. Some posters started to discuss in these threads whether these extremely small numerical fields outside the EM Drive were revealing "negative energy". Nothing to do with reality. Everything to do with the numerical solution of simultaneous equations.
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Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SeeShells on 12/12/2015 04:18 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456315#msg1456315">Quote from: Rodal on 12/12/2015 03:55 PM</a>
Your correct Dr. Rodal, but it needed to be discussed and resolved even if it is a numerical hiccup.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456308#msg1456308">Quote from: ThereIWas3 on 12/12/2015 03:40 PM</a>The negative Q values are a known artifact of the computational model used inside meep under certain conditions. It has nothing to do with physics.
Correct. It has nothing to do with physics.
It has nothing to do with reality.
Discussing this is similar to previous discussions incorrectly attaching physical significance to:
previous Meep models which included a Finite Difference mesh outside the EM Drive, which showed numerical magnitudes of the electromagnetic fields to be 24 orders of magnitude smaller than the fields inside the EM Drive. People (unfamiliar with numerical methods like Finite Difference solutions) were unaware that such numerical methods entail the solution of simultaneous equations and therefore that the magnitude of the fields outside the EM Drive instead of displaying a perfect zero will routinely display very small numbers associated with the numerical precision and ill-conditioning of inversion of matrices. Some posters started to discuss in these threads whether these extremely small numerical fields outside the EM Drive were revealing "negative energy". Nothing to do with reality. Everything to do with the numerical solution of simultaneous equations.
I'm glad it's behind us and the fractals shown in the boundaries of some of the first meep models are as well. We have come a long way to making sure meep can model our models. When we get solid data from the drive and solid data from meep we can begin to compare and run cross checks between the two. I hope the combining of both data sets will give us some tools to dig a little deeper, answer some questions and open up better ones.
This is my hope.
Shell -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/12/2015 04:38 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456330#msg1456330">Quote from: SeeShells on 12/12/2015 04:18 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456315#msg1456315">Quote from: Rodal on 12/12/2015 03:55 PM</a>
Your correct Dr. Rodal, but it needed to be discussed and resolved even if it is a numerical hiccup.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456308#msg1456308">Quote from: ThereIWas3 on 12/12/2015 03:40 PM</a>The negative Q values are a known artifact of the computational model used inside meep under certain conditions. It has nothing to do with physics.
Correct. It has nothing to do with physics.
It has nothing to do with reality.
Discussing this is similar to previous discussions incorrectly attaching physical significance to:
previous Meep models which included a Finite Difference mesh outside the EM Drive, which showed numerical magnitudes of the electromagnetic fields to be 24 orders of magnitude smaller than the fields inside the EM Drive. People (unfamiliar with numerical methods like Finite Difference solutions) were unaware that such numerical methods entail the solution of simultaneous equations and therefore that the magnitude of the fields outside the EM Drive instead of displaying a perfect zero will routinely display very small numbers associated with the numerical precision and ill-conditioning of inversion of matrices. Some posters started to discuss in these threads whether these extremely small numerical fields outside the EM Drive were revealing "negative energy". Nothing to do with reality. Everything to do with the numerical solution of simultaneous equations.
I'm glad it's behind us and the fractals shown in the boundaries of some of the first meep models are as well. We have come a long way to making sure meep can model our models. When we get solid data from the drive and solid data from meep we can begin to compare and run cross checks between the two. I hope the combining of both data sets will give us some tools to dig a little deeper, answer some questions and open up better ones.
This is my hope.
Shell
Yeap, the "fractal" contour images associated with very small numerical magnitude of fields is another example.
Whenever electromagnetic fields are displayed, they should preferably be displayed with a numerical table identifying the numerical value of the contours (to prevent people from looking at nonsensical small values that are numerical artifacts and thinking that they are significant)
Another example are Meep Q's of 10 million (due to https://en.wikipedia.org/wiki/Garbage_in,_garbage_out ).
In numerical experiments, just as in physical experiments, everything needs to be double-checked over and over.
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Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/12/2015 05:03 PM -
It is an ongoing process where one has to continuously go back and check and double-check.
As the great mathematician George Polya wrote in his classical book "How to Solve it":
1) First, you have to understand the problem.
What are you asked to find or show?
Can you restate the problem in your own words?
Can you think of a picture or a diagram that might help you understand the problem?
Is there enough information to enable you to find a solution?
Do you understand all the words used in stating the problem?
Do you need to ask a question to get the answer?
2) After understanding, then make a plan.
Guess and check
Make an orderly list
Eliminate possibilities
Use symmetry
Consider special cases
Use direct reasoning
Solve an equation
Look for a pattern
Draw a picture
Solve a simpler problem
Use a model
Work backward
Use a formula
Be creative
Use your head/noggin
3) Carry out the plan.
4) Look back on your work. Check and double check everything !
5) How could it be better?
(
)
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Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: ThereIWas3 on 12/12/2015 05:23 PM -
At aero's suggestion, I had meep generate at image at the end of the resonance calculations. This is interesting because the large-end diameter is 2.4 wavelengths and that is about how many cycles of color I see.
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Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: aero on 12/12/2015 05:30 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456261#msg1456261">Quote from: ThereIWas3 on 12/12/2015 12:57 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456199#msg1456199">Quote from: aero on 12/12/2015 03:13 AM</a>
Hmm - something strange is going on here. I just completed that run using Ez excitation and got nothing again. But this time the fields were formed, not like the Hz excitation which was just noise. See attached
I've been starting with your solution - I'll open the bandwidth and chase it down for my model.
Don't forget the other changes I mentioned earlier (http://forum.nasaspaceflight.com/index.php?topic=38577.msg1455937#msg1455937): BW=0.015 and gc=10
I didn't forget. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/12/2015 05:40 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456378#msg1456378">Quote from: ThereIWas3 on 12/12/2015 05:23 PM</a>
At aero's suggestion, I had meep generate at image at the end of the resonance calculations. This is interesting because the large-end diameter is 2.4 wavelengths and that is about how many cycles of color I see.
Some questions
1) What view does the image represent? Why does the image have rectangular boundaries? (the cross sections of Shell's frustrum of a cone are circumferential, while the planar views should be trapezium-shaped instead of rectangular).
2) What field is being displayed ? The E (or D) field? The H (or B) field?
3) Is the image representing a contour plot of the field? If so what are the numerical magnitudes of the contours? -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: ThereIWas3 on 12/12/2015 05:48 PM -
1. The image is square because all PNG images are rectangular. I see a circular edge there, though there seem to be leaks in the upper left and right corners. It is very soft-focus, probably because the meep resolution is only 100 for this run, to speed it up.
2. It is the H field.
3. It is a contour plot. The basic 'h5topng' utility does not add a scale legend. There is another way to make the image that can do that. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: ThereIWas3 on 12/12/2015 06:03 PM -
Here it is using a different way to generate the image from the same raw data.
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Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/12/2015 06:14 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456398#msg1456398">Quote from: ThereIWas3 on 12/12/2015 06:03 PM</a>
Here it is using a different way to generate the image from the same raw data.
Thank you, I understand now that the image represents the H field, but I don't understand the following
1) the contour plot represents the scalar magnitude of what vector component of H?
2) the coordinate directions of the image.
To interpret the image, it would be helpful if you could define something like this (replace as needed)
magnitude of H vector component in the Z direction (Hz)
Frustrum of a cone geometry:
Longitudinal direction (height of the frustrum): coordinate Z
_________________
Coordinates of the two-dimensional planar image of H:
Vertical Direction: Y
Horizontal Direction: X
Out-of-plane Direction: Z ( image taken corresponds to Z = ?, or "Image corresponds to Z at the small end", or "Image corresponds to Z at the large end") -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/12/2015 06:52 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456398#msg1456398">Quote from: ThereIWas3 on 12/12/2015 06:03 PM</a>
Here it is using a different way to generate the image from the same raw data.
The image shows relatively low magnitude values of the H field (10^(-7)). Perhaps this field in this direction (whatever direction it is supposed to be in) has a low value and it is not relevant. Have you looked at all the fields in all directions: Ex, Ey, Ez, Hz, Hy, Hz and determined that this is a relevant field?
The fact that the plot shows lack of symmetry is either indicative of:
1) Not one of the relevant field directions
or
2) If this is the result of a time-marching solution, not enough time has gone by for the fields to be well-formed into a standing mode well developed pattern
or
3) Unsymmetric field distribution is due to unsymmetric excitation (assuming a symmetric geometry of the frustum) -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: John J Gallagher on 12/12/2015 07:03 PM - Non cyanide silver plating solutions are fairly toxic so I was thinking that the parts could be fabricated out of fine silver sheet. I looked up todays prices on the Rio Grande site and found that a .010" thick 6" X 24" sheet costs about $130. :D
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Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/12/2015 07:08 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456443#msg1456443">Quote from: John J Gallagher on 12/12/2015 07:03 PM</a>
Non cyanide silver plating solutions are fairly toxic so I was thinking that the parts could be fabricated out of fine silver sheet. I looked up todays prices on the Rio Grande site and found that a .010" thick 6" X 24" sheet costs about $130. :D
Welcome to the forum :)
Your suggestion would also address the possible problem of porosity leading to lower conductivity (assuming that the silver sheets are fabricated such as resulting in a non-porous sheet)
On the other hand, there maybe a possible problem of waviness/non-flatness of the sheet due to being so thin, as the surface needs to be smooth for reflection purposes. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: OnlyMe on 12/12/2015 07:39 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456446#msg1456446">Quote from: Rodal on 12/12/2015 07:08 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456443#msg1456443">Quote from: John J Gallagher on 12/12/2015 07:03 PM</a>
Non cyanide silver plating solutions are fairly toxic so I was thinking that the parts could be fabricated out of fine silver sheet. I looked up todays prices on the Rio Grande site and found that a .010" thick 6" X 24" sheet costs about $130. :D
Welcome to the forum :)
Your suggestion would also address the possible problem of porosity leading to lower conductivity (assuming that the silver sheets are fabricated such as resulting in a non-porous sheet)
On the other hand, there maybe a possible problem of waviness/non-flatness of the sheet due to being so thin, as the surface needs to be smooth for reflection purposes.
Dr. Rodal,
If the sliver plating is greater than skin deapth, shouldn't that avoid the problems in the earlier linked article on the affect of plating? It seems the only issue at that point should be the purity of the plating... -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/12/2015 07:48 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456457#msg1456457">Quote from: OnlyMe on 12/12/2015 07:39 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456446#msg1456446">Quote from: Rodal on 12/12/2015 07:08 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456443#msg1456443">Quote from: John J Gallagher on 12/12/2015 07:03 PM</a>
Non cyanide silver plating solutions are fairly toxic so I was thinking that the parts could be fabricated out of fine silver sheet. I looked up todays prices on the Rio Grande site and found that a .010" thick 6" X 24" sheet costs about $130. :D
Welcome to the forum :)
Your suggestion would also address the possible problem of porosity leading to lower conductivity (assuming that the silver sheets are fabricated such as resulting in a non-porous sheet)
On the other hand, there maybe a possible problem of waviness/non-flatness of the sheet due to being so thin, as the surface needs to be smooth for reflection purposes.
Dr. Rodal,
If the sliver plating is greater than skin deapth, shouldn't that avoid the problems in the earlier linked article on the affect of plating? It seems the only issue at that point should be the purity of the plating...
It depends on the porosity morphology and whether the features range from sub-micrometer to hundreds of micrometers. Difficult to say anything without knowledge of the actual structure of the porosity. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: zen-in on 12/12/2015 08:23 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456443#msg1456443">Quote from: John J Gallagher on 12/12/2015 07:03 PM</a>
Non cyanide silver plating solutions are fairly toxic so I was thinking that the parts could be fabricated out of fine silver sheet. I looked up todays prices on the Rio Grande site and found that a .010" thick 6" X 24" sheet costs about $130. :D
That would be one solution for achieving the highest Q possible, but the Fine Silver sheet would have to be mounted on some kind of backing. Alone it would be almost as flimsy as household Aluminum foil. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SeeShells on 12/12/2015 08:26 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456443#msg1456443">Quote from: John J Gallagher on 12/12/2015 07:03 PM</a>
Non cyanide silver plating solutions are fairly toxic so I was thinking that the parts could be fabricated out of fine silver sheet. I looked up todays prices on the Rio Grande site and found that a .010" thick 6" X 24" sheet costs about $130. :D
I wore gloves and a mask and in a well ventilated area just to be safe.
Here is their MSDS if you would like to read.
Shell -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SeeShells on 12/12/2015 08:35 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456457#msg1456457">Quote from: OnlyMe on 12/12/2015 07:39 PM</a>
I asked the Tech Support on the quality of deposited silver and he assured me it is 99.9% silver. How much silver you lay down is dependent of time plating. With the little wand that comes in the kit it's very slow but you can increase the time by using a SS 3/8" rod and making a bath for your part ~3=4" deep and drop the rod about 2" into the soultion and about 2" up from the bottom.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456446#msg1456446">Quote from: Rodal on 12/12/2015 07:08 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456443#msg1456443">Quote from: John J Gallagher on 12/12/2015 07:03 PM</a>Non cyanide silver plating solutions are fairly toxic so I was thinking that the parts could be fabricated out of fine silver sheet. I looked up todays prices on the Rio Grande site and found that a .010" thick 6" X 24" sheet costs about $130. :D
Welcome to the forum :)
Your suggestion would also address the possible problem of porosity leading to lower conductivity (assuming that the silver sheets are fabricated such as resulting in a non-porous sheet)
On the other hand, there maybe a possible problem of waviness/non-flatness of the sheet due to being so thin, as the surface needs to be smooth for reflection purposes.
Dr. Rodal,
If the sliver plating is greater than skin deapth, shouldn't that avoid the problems in the earlier linked article on the affect of plating? It seems the only issue at that point should be the purity of the plating... -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: OnlyMe on 12/12/2015 08:51 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456479#msg1456479">Quote from: SeeShells on 12/12/2015 08:35 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456457#msg1456457">Quote from: OnlyMe on 12/12/2015 07:39 PM</a>
I asked the Tech Support on the quality of deposited silver and he assured me it is 99.9% silver. How much silver you lay down is dependent of time plating. With the little wand that comes in the kit it's very slow but you can increase the time by using a SS 3/8" rod and making a bath for your part ~3=4" deep and drop the rod about 2" into the soultion and about 2" up from the bottom.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456446#msg1456446">Quote from: Rodal on 12/12/2015 07:08 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456443#msg1456443">Quote from: John J Gallagher on 12/12/2015 07:03 PM</a>Non cyanide silver plating solutions are fairly toxic so I was thinking that the parts could be fabricated out of fine silver sheet. I looked up todays prices on the Rio Grande site and found that a .010" thick 6" X 24" sheet costs about $130. :D
Welcome to the forum :)
Your suggestion would also address the possible problem of porosity leading to lower conductivity (assuming that the silver sheets are fabricated such as resulting in a non-porous sheet)
On the other hand, there maybe a possible problem of waviness/non-flatness of the sheet due to being so thin, as the surface needs to be smooth for reflection purposes.
Dr. Rodal,
If the sliver plating is greater than skin deapth, shouldn't that avoid the problems in the earlier linked article on the affect of plating? It seems the only issue at that point should be the purity of the plating...
I remember you mentioned this earlier and now I will do the forbidden and assume...., that when electroplating the silver is laid down as atoms or close to it. Using the stainless steel electrode there would be no possibility of eroding clumps of silver from the electrode. The question would be whether the stainless leaches any iron or ?? into solution. But stainless steel does seem to be one of the suggested materials. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SeeShells on 12/12/2015 08:52 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456476#msg1456476">Quote from: zen-in on 12/12/2015 08:23 PM</a>
There are many plating companies out there who will gladly take your frustum and electroplate it with a pure silver layer and even with a gold flash to protect. Make sure you research the ones that specialize in waveguides for the semi industry that maybe local for you.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456443#msg1456443">Quote from: John J Gallagher on 12/12/2015 07:03 PM</a>Non cyanide silver plating solutions are fairly toxic so I was thinking that the parts could be fabricated out of fine silver sheet. I looked up todays prices on the Rio Grande site and found that a .010" thick 6" X 24" sheet costs about $130. :D
That would be one solution for achieving the highest Q possible, but the Fine Silver sheet would have to be mounted on some kind of backing. Alone it would be almost as flimsy as household Aluminum foil.
I looked into it at the start of this project but decided that O2 free copper was good enough until I found I could inexpensively do my own silver electroplating.
Shell -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SeeShells on 12/12/2015 08:58 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456481#msg1456481">Quote from: OnlyMe on 12/12/2015 08:51 PM</a>
When I did my first antenna 1/4 WL antenna (simple copper solid 12g wire) it took a long time to lay down what I figured was a good layer. I went online with Caswell Tech support and gave me the directions on how to do it a little faster. They made sure I was using a 316 SS rod (need to double check my notes but I believe it was 316 SS), that way you do not contaminate your surface with other metals.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456479#msg1456479">Quote from: SeeShells on 12/12/2015 08:35 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456457#msg1456457">Quote from: OnlyMe on 12/12/2015 07:39 PM</a>
I asked the Tech Support on the quality of deposited silver and he assured me it is 99.9% silver. How much silver you lay down is dependent of time plating. With the little wand that comes in the kit it's very slow but you can increase the time by using a SS 3/8" rod and making a bath for your part ~3=4" deep and drop the rod about 2" into the soultion and about 2" up from the bottom.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456446#msg1456446">Quote from: Rodal on 12/12/2015 07:08 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456443#msg1456443">Quote from: John J Gallagher on 12/12/2015 07:03 PM</a>Non cyanide silver plating solutions are fairly toxic so I was thinking that the parts could be fabricated out of fine silver sheet. I looked up todays prices on the Rio Grande site and found that a .010" thick 6" X 24" sheet costs about $130. :D
Welcome to the forum :)
Your suggestion would also address the possible problem of porosity leading to lower conductivity (assuming that the silver sheets are fabricated such as resulting in a non-porous sheet)
On the other hand, there maybe a possible problem of waviness/non-flatness of the sheet due to being so thin, as the surface needs to be smooth for reflection purposes.
Dr. Rodal,
If the sliver plating is greater than skin deapth, shouldn't that avoid the problems in the earlier linked article on the affect of plating? It seems the only issue at that point should be the purity of the plating...
I remember you mentioned this earlier and now I will do the forbidden and assume...., that when electroplating the silver is laid down as atoms or close to it. Using the stainless steel electrode there would be no possibility of eroding clumps of silver from the electrode. The question would be whether the stainless leaches any iron or ?? into solution. But stainless steel does seem to be one of the suggested materials. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/12/2015 09:02 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456481#msg1456481">Quote from: OnlyMe on 12/12/2015 08:51 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456479#msg1456479">Quote from: SeeShells on 12/12/2015 08:35 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456457#msg1456457">Quote from: OnlyMe on 12/12/2015 07:39 PM</a>
I asked the Tech Support on the quality of deposited silver and he assured me it is 99.9% silver. How much silver you lay down is dependent of time plating. With the little wand that comes in the kit it's very slow but you can increase the time by using a SS 3/8" rod and making a bath for your part ~3=4" deep and drop the rod about 2" into the soultion and about 2" up from the bottom.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456446#msg1456446">Quote from: Rodal on 12/12/2015 07:08 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456443#msg1456443">Quote from: John J Gallagher on 12/12/2015 07:03 PM</a>Non cyanide silver plating solutions are fairly toxic so I was thinking that the parts could be fabricated out of fine silver sheet. I looked up todays prices on the Rio Grande site and found that a .010" thick 6" X 24" sheet costs about $130. :D
Welcome to the forum :)
Your suggestion would also address the possible problem of porosity leading to lower conductivity (assuming that the silver sheets are fabricated such as resulting in a non-porous sheet)
On the other hand, there maybe a possible problem of waviness/non-flatness of the sheet due to being so thin, as the surface needs to be smooth for reflection purposes.
Dr. Rodal,
If the sliver plating is greater than skin deapth, shouldn't that avoid the problems in the earlier linked article on the affect of plating? It seems the only issue at that point should be the purity of the plating...
I remember you mentioned this earlier and now I will do the forbidden and assume...., that when electroplating the silver is laid down as atoms or close to it. Using the stainless steel electrode there would be no possibility of eroding clumps of silver from the electrode. The question would be whether the stainless leaches any iron or ?? into solution. But stainless steel does seem to be one of the suggested materials.
Chapter on porosity (as well as micro-cracks and their effects) from a book, on the Internet. (I'm not responsible for the horrible highlighting :) which does not highlight anything in particular)
http://www.tau.ac.il/~chemlaba/Files/Electrodeposition/13208_08.pdf -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: LasJayhawk on 12/12/2015 09:38 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456349#msg1456349">Quote from: Rodal on 12/12/2015 04:38 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456330#msg1456330">Quote from: SeeShells on 12/12/2015 04:18 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456315#msg1456315">Quote from: Rodal on 12/12/2015 03:55 PM</a>
Your correct Dr. Rodal, but it needed to be discussed and resolved even if it is a numerical hiccup.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456308#msg1456308">Quote from: ThereIWas3 on 12/12/2015 03:40 PM</a>The negative Q values are a known artifact of the computational model used inside meep under certain conditions. It has nothing to do with physics.
Correct. It has nothing to do with physics.
It has nothing to do with reality.
Discussing this is similar to previous discussions incorrectly attaching physical significance to:
previous Meep models which included a Finite Difference mesh outside the EM Drive, which showed numerical magnitudes of the electromagnetic fields to be 24 orders of magnitude smaller than the fields inside the EM Drive. People (unfamiliar with numerical methods like Finite Difference solutions) were unaware that such numerical methods entail the solution of simultaneous equations and therefore that the magnitude of the fields outside the EM Drive instead of displaying a perfect zero will routinely display very small numbers associated with the numerical precision and ill-conditioning of inversion of matrices. Some posters started to discuss in these threads whether these extremely small numerical fields outside the EM Drive were revealing "negative energy". Nothing to do with reality. Everything to do with the numerical solution of simultaneous equations.
I'm glad it's behind us and the fractals shown in the boundaries of some of the first meep models are as well. We have come a long way to making sure meep can model our models. When we get solid data from the drive and solid data from meep we can begin to compare and run cross checks between the two. I hope the combining of both data sets will give us some tools to dig a little deeper, answer some questions and open up better ones.
This is my hope.
Shell
Yeap, the "fractal" contour images associated with very small numerical magnitude of fields is another example.
Whenever electromagnetic fields are displayed, they should preferably be displayed with a numerical table identifying the numerical value of the contours (to prevent people from looking at nonsensical small values that are numerical artifacts and thinking that they are significant)
Another example are Meep Q's of 10 million (due to https://en.wikipedia.org/wiki/Garbage_in,_garbage_out ).
In numerical experiments, just as in physical experiments, everything needs to be double-checked over and over.
I would be willing to ignore artifacts of a model if I had the foggiest notion of how the thing worked. Since I can't grasp why it seems to work, I'm not willing to ignore anything. Kind of the reason I put the TurboEncabulator reference in the post.
In my somewhat small mind ( compared to the group here) I can't help noticing aa parallel to the speaker in a 1929 Philco highboy, a device for turning electromagnetic energy into air movement. Not very efficient, but once something like that works, the room for improvement is massive.
I'm banking on Shell to make some thrust that is beyond the realm of noise so I can come in and make it sing. :) -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SeeShells on 12/12/2015 09:39 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456488#msg1456488">Quote from: Rodal on 12/12/2015 09:02 PM</a>
We had some real problems with porosity of multi-layered surfaces when separating the wafers into single dies with our equipment. This is only considering the mechanical stresses and the chipping of the materials from micro-seed fracturing caused by voids in the materials by the sometimes multiple bonding techniques.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456481#msg1456481">Quote from: OnlyMe on 12/12/2015 08:51 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456479#msg1456479">Quote from: SeeShells on 12/12/2015 08:35 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456457#msg1456457">Quote from: OnlyMe on 12/12/2015 07:39 PM</a>
I asked the Tech Support on the quality of deposited silver and he assured me it is 99.9% silver. How much silver you lay down is dependent of time plating. With the little wand that comes in the kit it's very slow but you can increase the time by using a SS 3/8" rod and making a bath for your part ~3=4" deep and drop the rod about 2" into the soultion and about 2" up from the bottom.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456446#msg1456446">Quote from: Rodal on 12/12/2015 07:08 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456443#msg1456443">Quote from: John J Gallagher on 12/12/2015 07:03 PM</a>Non cyanide silver plating solutions are fairly toxic so I was thinking that the parts could be fabricated out of fine silver sheet. I looked up todays prices on the Rio Grande site and found that a .010" thick 6" X 24" sheet costs about $130. :D
Welcome to the forum :)
Your suggestion would also address the possible problem of porosity leading to lower conductivity (assuming that the silver sheets are fabricated such as resulting in a non-porous sheet)
On the other hand, there maybe a possible problem of waviness/non-flatness of the sheet due to being so thin, as the surface needs to be smooth for reflection purposes.
Dr. Rodal,
If the sliver plating is greater than skin deapth, shouldn't that avoid the problems in the earlier linked article on the affect of plating? It seems the only issue at that point should be the purity of the plating...
I remember you mentioned this earlier and now I will do the forbidden and assume...., that when electroplating the silver is laid down as atoms or close to it. Using the stainless steel electrode there would be no possibility of eroding clumps of silver from the electrode. The question would be whether the stainless leaches any iron or ?? into solution. But stainless steel does seem to be one of the suggested materials.
Chapter from a book, on the Internet. (I'm not responsible for the horrible highlighting :) which does not highlight anything in particular)
http://www.tau.ac.il/~chemlaba/Files/Electrodeposition/13208_08.pdf
It's not a great leap of faith to see where porosity of a electroplated material could effect the electrical properties by increasing porosity and thereby the conductivity or permeability at higher frequencies.
A couple of points in laying down >40um of silver. Most of your defects in materials with porosity occurs at the boundary layers between the two metals. The Cu can have voids and oxidation, contaminates that are not removed in the pre-process or from simple grubby fingers touching it. Preparing the surface is critical.
The first .1 to maybe 10um of silver you lay down will contain the most defects from you simply not being in a cleanroom fab to prepare the copper, although after you lay your first layers the voids and holes decrease to a level that should not effect the characteristics of the silver on the final 20um. This is why I wanted to at least lay down >40um of silver to build out of that area of first bond.
Now any RF actions will be under 5um and not effected by the first bond of silver onto the copper.
That said it will be interesting when we nail down meep to compare let's say Q in the real world to what meep says and how close the two are.
Just my 2 cents and back to getting some more work done.
Shell
Added: on second thought I think a short snowy afternoon nap is in order. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: TheTraveller on 12/12/2015 10:11 PM -
Update on my latest build.
Cutting copper next week. Using a 1.2kW Panasonic maggie, driven by a modified Panasonic maggie inverter power supply. Will be using a 5kv vac switch to remove filament power once the maggie is generating microwaves. Expect 1st Force measurements early Jan 2016.
Report back then. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: John J Gallagher on 12/12/2015 10:40 PM - Fine and sterling silver sheets are available in thicknesses of .010" to .102" The thinner gauges could be bonded to copper with soft solder to enable a more robust build. Prices range depending on the market but are $1.24 per square inch for the .010" material and $10.96 for the .102" The resistivity of fine silver is 1.67 where as the sterling silvers range from 2.0 to 2.5 . These materials are cast and rolled to thickness so I would think that they will exhibit bulk values. Fine silver will stay soft and can be worked using leather hammers and turned hard wood molds so domed sections can be fabricated with relative ease.
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SeeShells on 12/12/2015 10:57 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456511#msg1456511">Quote from: John J Gallagher on 12/12/2015 10:40 PM</a>
Fine and sterling silver sheets are available in thicknesses of .010" to .102" The thinner gauges could be bonded to copper with soft solder to enable a more robust build. Prices range depending on the market but are $1.24 per square inch for the .010" material and $10.96 for the .102" The resistivity of fine silver is 1.67 where as the sterling silvers range from 2.0 to 2.5 . These materials are cast and rolled to thickness so I would think that they will exhibit bulk values. Fine silver will stay soft and can be worked using leather hammers and turned hard wood molds so domed sections can be fabricated with relative ease.
The resistivity of O2 free copper is 1.72 Ohms cm 10-6 (10.371 Ohms cir-mil/ft) are your figures in cm?
This copper is a little tough to work with. .032" or 0.8mm
Shell -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: aero on 12/13/2015 12:37 AM - Seems to me that if you can get a reproducible signal with silver, you should get one using copper, too. I would think that any more silver will just detract from the effort, and the cost would certainly discourage other DYI'er from entering the fray. I mean, if you use silver and get positive results, everyone will think silver is needed, hence they will be discouraged by the cost.
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: OnlyMe on 12/13/2015 12:51 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456546#msg1456546">Quote from: aero on 12/13/2015 12:37 AM</a>
Seems to me that if you can get a reproducible signal with silver, you should get one using copper, too. I would think that any more silver will just detract from the effort, and the cost would certainly discourage other DYI'er from entering the fray. I mean, if you use silver and get positive results, everyone will think silver is needed, hence they will be discouraged by the cost.
I thought something Dr. Rodal said earlier was that at microwave frequencies there was little difference between silver and copper? -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/13/2015 01:00 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456552#msg1456552">Quote from: OnlyMe on 12/13/2015 12:51 AM</a>
Nope, take another gander at http://forum.nasaspaceflight.com/index.php?topic=39004.msg1455988#msg1455988 (pure silver should result in 40% higher Q than pure copper if both are non-porous and free of defects).<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456546#msg1456546">Quote from: aero on 12/13/2015 12:37 AM</a>Seems to me that if you can get a reproducible signal with silver, you should get one using copper, too. I would think that any more silver will just detract from the effort, and the cost would certainly discourage other DYI'er from entering the fray. I mean, if you use silver and get positive results, everyone will think silver is needed, hence they will be discouraged by the cost.
I thought something Dr. Rodal said earlier was that at microwave frequencies there was little difference between silver and copper?
On the other hand, according to
Radio Frequency Performance of Electro Plated Finishes
A.M. Fowler
Proceedings IREE Australia May 1970
http://k6mhe.com/n7ws/Plating.pdf
, a porous silver coating can give you a much lower Q of only half as much as pure solid copper. (http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456018#msg1456018) -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: OnlyMe on 12/13/2015 01:07 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456553#msg1456553">Quote from: Rodal on 12/13/2015 01:00 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456552#msg1456552">Quote from: OnlyMe on 12/13/2015 12:51 AM</a>
Nope, take another gander at http://forum.nasaspaceflight.com/index.php?topic=39004.msg1455988#msg1455988 (pure silver should result in 40% higher Q than pure copper if both are non-porous and free of defects).<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456546#msg1456546">Quote from: aero on 12/13/2015 12:37 AM</a>Seems to me that if you can get a reproducible signal with silver, you should get one using copper, too. I would think that any more silver will just detract from the effort, and the cost would certainly discourage other DYI'er from entering the fray. I mean, if you use silver and get positive results, everyone will think silver is needed, hence they will be discouraged by the cost.
I thought something Dr. Rodal said earlier was that at microwave frequencies there was little difference between silver and copper?
On the other hand, according to
Radio Frequency Performance of Electro Plated Finishes
A.M. Fowler
Proceedings IREE Australia May 1970
http://k6mhe.com/n7ws/Plating.pdf
, a porous silver coating can give you a much lower Q of only half as much as pure solid copper. (http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456018#msg1456018)
Yes, I remember now. Have to think what I was confusing... -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SeeShells on 12/13/2015 01:08 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456553#msg1456553">Quote from: Rodal on 12/13/2015 01:00 AM</a>
If your not sure go with just plain copper and it helps to keep the cost down.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456552#msg1456552">Quote from: OnlyMe on 12/13/2015 12:51 AM</a>
Nope, take another gander at http://forum.nasaspaceflight.com/index.php?topic=39004.msg1455988#msg1455988 (pure silver should result in 40% higher Q than pure copper if both are non-porous and free of defects).<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456546#msg1456546">Quote from: aero on 12/13/2015 12:37 AM</a>Seems to me that if you can get a reproducible signal with silver, you should get one using copper, too. I would think that any more silver will just detract from the effort, and the cost would certainly discourage other DYI'er from entering the fray. I mean, if you use silver and get positive results, everyone will think silver is needed, hence they will be discouraged by the cost.
I thought something Dr. Rodal said earlier was that at microwave frequencies there was little difference between silver and copper?
On the other hand, according to
Radio Frequency Performance of Electro Plated Finishes
A.M. Fowler
Proceedings IREE Australia May 1970
http://k6mhe.com/n7ws/Plating.pdf
, a porous silver coating can give you a much lower Q of only half as much as pure solid copper. (http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456018#msg1456018)
Next is O2 free copper
Next copper with silver electroplating and can be plain copper.
Next O2 Copper with silver electroplating with gold flash <1um
Next pure silver for a trophy EMDrive. ;)
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SeeShells on 12/13/2015 01:11 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456546#msg1456546">Quote from: aero on 12/13/2015 12:37 AM</a>
Seems to me that if you can get a reproducible signal with silver, you should get one using copper, too. I would think that any more silver will just detract from the effort, and the cost would certainly discourage other DYI'er from entering the fray. I mean, if you use silver and get positive results, everyone will think silver is needed, hence they will be discouraged by the cost.
If you do the silver correctly and avoid the pitfalls of holes and defects you can get up to a 40% boost in just Q. It did cost some but not that much. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: OnlyMe on 12/13/2015 01:22 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456559#msg1456559">Quote from: Rodal on 12/13/2015 01:17 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456555#msg1456555">Quote from: OnlyMe on 12/13/2015 01:07 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456553#msg1456553">Quote from: Rodal on 12/13/2015 01:00 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456552#msg1456552">Quote from: OnlyMe on 12/13/2015 12:51 AM</a>
Nope, take another gander at http://forum.nasaspaceflight.com/index.php?topic=39004.msg1455988#msg1455988 (pure silver should result in 40% higher Q than pure copper if both are non-porous and free of defects).<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456546#msg1456546">Quote from: aero on 12/13/2015 12:37 AM</a>Seems to me that if you can get a reproducible signal with silver, you should get one using copper, too. I would think that any more silver will just detract from the effort, and the cost would certainly discourage other DYI'er from entering the fray. I mean, if you use silver and get positive results, everyone will think silver is needed, hence they will be discouraged by the cost.
I thought something Dr. Rodal said earlier was that at microwave frequencies there was little difference between silver and copper?
On the other hand, according to
Radio Frequency Performance of Electro Plated Finishes
A.M. Fowler
Proceedings IREE Australia May 1970
http://k6mhe.com/n7ws/Plating.pdf
, a porous silver coating can give you a much lower Q of only half as much as pure solid copper. (http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456018#msg1456018)
Yes, I remember now. Have to think what I was confusing...
Probably thinking of gold (which is closer to copper in conductivity), just a little lower than pure copper, but gold does not corrode.
I think I was confusing electrical conductivity. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SeeShells on 12/13/2015 01:51 AM -
43 years ago I was watching them walk on the moon... for the last time.
I'll never forget them driving around in their very cool looking lunar rover, when that baby pealed out and threw moon dust into the vacuum of space I cheered. I never thought 43 years later we would never be back. It saddened me then and it saddens me now. I always believed we were good enough to go back, claim what was in our neighborhood, our birthright, but we didn't. We should have.
I don't know if this Drive will give us the keys to the neighborhood of space, but it eases the sadness these last 43 years have wrought by me trying and giving what I can to build and test this drive.
Who would have thought a feather of thrust could carry so much weight?
Shell
http://io9.com/the-real-story-of-apollo-17-and-why-we-never-went-ba-1670503448 -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: OnlyMe on 12/13/2015 02:03 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456566#msg1456566">Quote from: SeeShells on 12/13/2015 01:51 AM</a>
43 years ago I was watching them walk on the moon... for the last time.
I'll never forget them driving around in their very cool looking lunar rover, when that baby pealed out and threw moon dust into the vacuum of space I cheered. I never thought 43 years later we would never be back. It saddened me then and it saddens me now. I always believed we were good enough to go back, claim what was in our neighborhood, our birthright, but we didn't. We should have.
I don't know if this Drive will give us the keys to the neighborhood of space, but it eases the sadness these last 43 years have wrought by me trying and giving what I can to build and test this drive.
Who would have thought a feather of thrust could carry so much weight?
Shell
http://io9.com/the-real-story-of-apollo-17-and-why-we-never-went-ba-1670503448
You know I don't remember the last trip, but I do remember that first step. All gathered around round the TV and the excitement when.., and then my grandfather who had seen gunfights in the streets of Saint Louis broke in to tell us all it was just a Hollywood movie. He never did believe it. And I'll never forget...
How big a the feather? :) -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SteveD on 12/13/2015 05:27 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456260#msg1456260">Quote from: OnlyMe on 12/12/2015 12:54 PM</a>
Whatever is going on with the EMDrive, it seems far more likely that the dynamics of the boundary conditions inside the drive, together with an asymmetry in the microwave field density, leads to a asymmetry in the transfer of momentum between the microwaves and the frustum. The issue of relativistic velocities from a constant classical thrust resulting in free energy, is a special relativity problem that should wait until we have some proof that relativistic velocities are even possible.
Personally, I've just been looking at what little data we have and been trying to use it to assign a ballpark probability of how this thing works at a pseudocode level (which risks ending up in pseudoscience pretty quickly). My take is that the drive is a speaker in space. The rf is generating some kind of spacetime wave that has a frequency and can be doppler shifted. The answer to the question of how does a spaceship powered by an EMDrive slow down is the same as how does a photon rocket slow down.
That would explain why the dielectric experiments report so much less thrust. If you have two dielectric disks and a endplate you've got three surfaces that are producing these waves. The waves are interfering with each other, killing the thrust generation. Need to look more at Woodwards work. Wonder if he might be basically right on theory, but having the thrust in his tests killed due to construction issues. (I suppose the next crackpot question is -- if these doppler shifted waves exist -- can they be used to build an Alcubierre Drive). -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SteveD on 12/13/2015 05:39 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456476#msg1456476">Quote from: zen-in on 12/12/2015 08:23 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456443#msg1456443">Quote from: John J Gallagher on 12/12/2015 07:03 PM</a>
Non cyanide silver plating solutions are fairly toxic so I was thinking that the parts could be fabricated out of fine silver sheet. I looked up todays prices on the Rio Grande site and found that a .010" thick 6" X 24" sheet costs about $130. :D
That would be one solution for achieving the highest Q possible, but the Fine Silver sheet would have to be mounted on some kind of backing. Alone it would be almost as flimsy as household Aluminum foil.
Hum, posterboard/cardboard with the fine sheet over it for the frustum and the two endplates in a self-supporting configuration of something sturdier based on the NSF-1701 design?
Actually, don't try this with posterboard if it's anything but a very low power solid state design. I worry that it simply won't be ablet to handle the heat involved. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SteveD on 12/13/2015 05:41 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456479#msg1456479">Quote from: SeeShells on 12/12/2015 08:35 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456457#msg1456457">Quote from: OnlyMe on 12/12/2015 07:39 PM</a>
I asked the Tech Support on the quality of deposited silver and he assured me it is 99.9% silver. How much silver you lay down is dependent of time plating. With the little wand that comes in the kit it's very slow but you can increase the time by using a SS 3/8" rod and making a bath for your part ~3=4" deep and drop the rod about 2" into the soultion and about 2" up from the bottom.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456446#msg1456446">Quote from: Rodal on 12/12/2015 07:08 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456443#msg1456443">Quote from: John J Gallagher on 12/12/2015 07:03 PM</a>Non cyanide silver plating solutions are fairly toxic so I was thinking that the parts could be fabricated out of fine silver sheet. I looked up todays prices on the Rio Grande site and found that a .010" thick 6" X 24" sheet costs about $130. :D
Welcome to the forum :)
Your suggestion would also address the possible problem of porosity leading to lower conductivity (assuming that the silver sheets are fabricated such as resulting in a non-porous sheet)
On the other hand, there maybe a possible problem of waviness/non-flatness of the sheet due to being so thin, as the surface needs to be smooth for reflection purposes.
Dr. Rodal,
If the sliver plating is greater than skin deapth, shouldn't that avoid the problems in the earlier linked article on the affect of plating? It seems the only issue at that point should be the purity of the plating...
Urm, isn't the question the conductivity of the plating. Would it be possible to grab one of the scraps you practiced on and check the conductivity against a scrap of the raw copper? -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SteveD on 12/13/2015 06:41 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456505#msg1456505">Quote from: TheTraveller on 12/12/2015 10:11 PM</a>
Update on my latest build.
Cutting copper next week. Using a 1.2kW Panasonic maggie, driven by a modified Panasonic maggie inverter power supply. Will be using a 5kv vac switch to remove filament power once the maggie is generating microwaves. Expect 1st Force measurements early Jan 2016.
Report back then.
Am I reading that right that you are using a magnetron feeding directly from a waveguide on top of the frustum. Not sure you arent' being overly optimistic on your Q.
In any event, here's a spreadsheet that I think might help calculate the thermal lift from the air inside the frustum. While the figures on the bottom, energy to heat the air inside the frustum one degree, are still a work in progress -- if you dump 1200watts in there you've got a good chance that things get hot as hell.
BTW welcome back. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: TheTraveller on 12/13/2015 08:09 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456611#msg1456611">Quote from: SteveD on 12/13/2015 06:41 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456505#msg1456505">Quote from: TheTraveller on 12/12/2015 10:11 PM</a>
Update on my latest build.
Cutting copper next week. Using a 1.2kW Panasonic maggie, driven by a modified Panasonic maggie inverter power supply. Will be using a 5kv vac switch to remove filament power once the maggie is generating microwaves. Expect 1st Force measurements early Jan 2016.
Report back then.
Am I reading that right that you are using a magnetron feeding directly from a waveguide on top of the frustum. Not sure you arent' being overly optimistic on your Q.
In any event, here's a spreadsheet that I think might help calculate the thermal lift from the air inside the frustum. While the figures on the bottom, energy to heat the air inside the frustum one degree, are still a work in progress -- if you dump 1200watts in there you've got a good chance that things get hot as hell.
BTW welcome back.
Thanks for the feedback. Will have a look at it.
No waveguide used.
Magnetron bolts directly to big end plate launcher with the antenna inside the frustum at the centre of the big end plate to excite TM113 mode. Mounts like Dave's magneton in NSF-1701 as attached.
Magnetron output power is adjustable from around 100W to 1,200W as the full wave voltage doubler inverter power supply control circuits adjust and regulate magnetron current to be constant. This also helps to reduce maggie freq splatter below that measured with simple 1/2 wave voltage doubler power supplies.
Once my spectrum scanner arrives, will be able to measure the freq splatter width generated by both types of maggie & power supplies. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SeeShells on 12/13/2015 12:41 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456569#msg1456569">Quote from: OnlyMe on 12/13/2015 02:03 AM</a>
How big a the feather? :)<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456566#msg1456566">Quote from: SeeShells on 12/13/2015 01:51 AM</a>43 years ago I was watching them walk on the moon... for the last time.
I'll never forget them driving around in their very cool looking lunar rover, when that baby pealed out and threw moon dust into the vacuum of space I cheered. I never thought 43 years later we would never be back. It saddened me then and it saddens me now. I always believed we were good enough to go back, claim what was in our neighborhood, our birthright, but we didn't. We should have.
I don't know if this Drive will give us the keys to the neighborhood of space, but it eases the sadness these last 43 years have wrought by me trying and giving what I can to build and test this drive.
Who would have thought a feather of thrust could carry so much weight?
Shell
http://io9.com/the-real-story-of-apollo-17-and-why-we-never-went-ba-1670503448
You know I don't remember the last trip, but I do remember that first step. All gathered around round the TV and the excitement when.., and then my grandfather who had seen gunfights in the streets of Saint Louis broke in to tell us all it was just a Hollywood movie. He never did believe it. And I'll never forget...
How big a the feather? :)
Depends on if it's in a vacuum or air, doesn't it? Not ready yet Doc.
Shell -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/13/2015 03:29 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456624#msg1456624">Quote from: TheTraveller on 12/13/2015 08:09 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456611#msg1456611">Quote from: SteveD on 12/13/2015 06:41 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456505#msg1456505">Quote from: TheTraveller on 12/12/2015 10:11 PM</a>
Update on my latest build.
Cutting copper next week. Using a 1.2kW Panasonic maggie, driven by a modified Panasonic maggie inverter power supply. Will be using a 5kv vac switch to remove filament power once the maggie is generating microwaves. Expect 1st Force measurements early Jan 2016.
Report back then.
Am I reading that right that you are using a magnetron feeding directly from a waveguide on top of the frustum. Not sure you arent' being overly optimistic on your Q.
In any event, here's a spreadsheet that I think might help calculate the thermal lift from the air inside the frustum. While the figures on the bottom, energy to heat the air inside the frustum one degree, are still a work in progress -- if you dump 1200watts in there you've got a good chance that things get hot as hell.
BTW welcome back.
Thanks for the feedback. Will have a look at it.
No waveguide used.
Magnetron bolts directly to big end plate launcher with the antenna inside the frustum at the centre of the big end plate to excite TM113 mode. Mounts like Dave's magneton in NSF-1701 as attached.
Magnetron output power is adjustable from around 100W to 1,200W as the full wave voltage doubler inverter power supply control circuits adjust and regulate magnetron current to be constant. This also helps to reduce maggie freq splatter below that measured with simple 1/2 wave voltage doubler power supplies.
Once my spectrum scanner arrives, will be able to measure the freq splatter width generated by both types of maggie & power supplies.
On your post http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456624#msg1456624 you state that the Magnetron will excite a transverse MAGNETIC CYLINDRICAL cavity mode TM113
<<Magnetron bolts directly to big end plate launcher with the antenna inside the frustum at the centre of the big end plate to excite TM113 mode>>
while the image for your post http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456505#msg1456505
(http://forum.nasaspaceflight.com/xindex.php,qaction=dlattach,3Btopic=39004.0,3Battach=1085234,3Bimage.pagespeed.ic.ypRnCOoAMA.webp)
states that the Magnetron will excite resonance via a transverse ELECTRIC CYLINDRICAL cavity mode TE013
Completely different modes, and the fact is that the cavity in your proposed experiment is NOT a cylindrical cavity, but it is a frustum of a cone, a truncated cone, excited by a magnetron. A Magnetron can excite modes in a truncated cone that have no equivalence in a cylindrical cavity. Many of the Meep runs discussed in these threads show modes that are asymmetric and have no equivalence in cylindrical cavities. (Your spreadsheet cannot excite such asymmetric modes that do not exist in cylindrical cavities so your spreadsheet will be unable to predict whether such an asymmetric mode will be excited in the actual experiment.)
We look forward to discussion of actual experimental data to determine what actual mode shape will be excited. Looking forward to actual experimental verification of the mode shape (using a thermal camera as done by NASA).
__________________________
(*) Neither Yang nor Shawyer have ever published actual experimental data (with a thermal camera) proving what actual mode shapes were excited in their experiments. NASA verified their mode shape in one of their experiments, as per Paul March discussion in previous threads. More experimental data is needed that verifies actual mode shapes excited in EM Drive experiments, to understand what is going on in these experiments.
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: TheTraveller on 12/13/2015 03:52 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456747#msg1456747">Quote from: Rodal on 12/13/2015 03:29 PM</a>
states that the Magnetron will excite a transverse ELECTRIC mode for a CYLINDRICAL cavity TE013
The drawing states nothing about the excited mode, only that the frustum has a TE013 resonance at 2.449 GHz as per my EmDrive Design spreadsheet, which has it's resonance predictions match with those of SPR's in house system to +-0.5%
As TE013 and TM113 have the same guide wavelength and frustum resonance in this model, using the magnetron's 1/4 wave stub antenna in the centre of the big end plate will excite the TM113 resonant mode and not the TE013 mode.
Cullen 15 makes it clear that radiation pressure on a end plate in a waveguide is not directly dependent on excited mode but instead is dependent on guide wavelength, which can be effected by excited mode.
If you wish to continue this conversation please join the EmDriveResearch forum as the next comment I make on this subject on this forum will be my final test result report, which I expect to complete in Jan 2016. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SeeShells on 12/13/2015 04:11 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456747#msg1456747">Quote from: Rodal on 12/13/2015 03:29 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456624#msg1456624">Quote from: TheTraveller on 12/13/2015 08:09 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456611#msg1456611">Quote from: SteveD on 12/13/2015 06:41 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456505#msg1456505">Quote from: TheTraveller on 12/12/2015 10:11 PM</a>
Update on my latest build.
Cutting copper next week. Using a 1.2kW Panasonic maggie, driven by a modified Panasonic maggie inverter power supply. Will be using a 5kv vac switch to remove filament power once the maggie is generating microwaves. Expect 1st Force measurements early Jan 2016.
Report back then.
Am I reading that right that you are using a magnetron feeding directly from a waveguide on top of the frustum. Not sure you arent' being overly optimistic on your Q.
In any event, here's a spreadsheet that I think might help calculate the thermal lift from the air inside the frustum. While the figures on the bottom, energy to heat the air inside the frustum one degree, are still a work in progress -- if you dump 1200watts in there you've got a good chance that things get hot as hell.
BTW welcome back.
Thanks for the feedback. Will have a look at it.
No waveguide used.
Magnetron bolts directly to big end plate launcher with the antenna inside the frustum at the centre of the big end plate to excite TM113 mode. Mounts like Dave's magneton in NSF-1701 as attached.
Magnetron output power is adjustable from around 100W to 1,200W as the full wave voltage doubler inverter power supply control circuits adjust and regulate magnetron current to be constant. This also helps to reduce maggie freq splatter below that measured with simple 1/2 wave voltage doubler power supplies.
Once my spectrum scanner arrives, will be able to measure the freq splatter width generated by both types of maggie & power supplies.
On your post http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456624#msg1456624 you state that the Magnetron will excite a transverse MAGNETIC CYLINDRICAL cavity mode TM113
<<Magnetron bolts directly to big end plate launcher with the antenna inside the frustum at the centre of the big end plate to excite TM113 mode>>
while the image for your post http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456505#msg1456505
(http://forum.nasaspaceflight.com/xindex.php,qaction=dlattach,3Btopic=39004.0,3Battach=1085234,3Bimage.pagespeed.ic.ypRnCOoAMA.webp)
states that the Magnetron will excite resonance via a transverse ELECTRIC CYLINDRICAL cavity mode TE013
Completely different modes, and the fact is that the cavity in your proposed experiment is NOT a cylindrical cavity, but it is a frustum of a cone, a truncated cone, excited by a magnetron. A Magnetron can excite modes in a truncated cone that have no equivalence in a cylindrical cavity. Many of the Meep runs discussed in these threads show modes that are asymmetric and have no equivalence in cylindrical cavities. (Your spreadsheet cannot excite such asymmetric modes that do not exist in cylindrical cavities so your spreadsheet will be unable to predict whether such an asymmetric mode will be excited in the actual experiment.)
We look forward to discussion of actual experimental data to determine what actual mode shape will be excited. Looking forward to actual experimental verification of the mode shape (using a thermal camera as done by NASA).
__________________________
(*) Neither Yang nor Shawyer have ever published actual experimental data (with a thermal camera) proving what actual mode shapes were excited in their experiments. NASA verified their mode shape in one of their experiments, as per Paul March discussion in previous threads. More experimental data is needed that verifies actual mode shapes excited in EM Drive experiments, to understand what is going on in these experiments.
I agree with this a lot. The one way to show the mode generated is by a thermal camera. When we got what we thought was the copper defined for the drude model in meep aero ran a series of meep animations.
https://drive.google.com/drive/folders/0B1XizxEfB23tbVYwc1Nsa29yZlk
I need to compare this meep to what we will see in the real world, I didn't get a chance to do the camera before I fried one of my waveguide antennas and re-doing it with a couple minor changes to the antennas that should help from turning my antenna into a match like object. ;)
Shell -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/13/2015 04:29 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456770#msg1456770">Quote from: TheTraveller on 12/13/2015 03:52 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456747#msg1456747">Quote from: Rodal on 12/13/2015 03:29 PM</a>
states that the Magnetron will excite a transverse ELECTRIC mode for a CYLINDRICAL cavity TE013
The drawing states nothing about the excited mode, only that the frustum has a TE013 resonance at 2.449 GHz as per my EmDrive Design spreadsheet, which has it's resonance predictions match with those of SPR's in house system to +-0.5%
As TE013 and TM113 have the same guide wavelength and frustum resonance in this model, using the magnetron's 1/4 wave stub antenna in the centre of the big end plate will excite the TM113 resonant mode and not the TE013 mode.
Cullen 15 makes it clear that radiation pressure on a end plate in a waveguide is not directly dependent on excited mode but instead is dependent on guide wavelength, which can be effected by excited mode.
If you wish to continue this conversation please join the EmDriveResearch forum as the next comment I make on this subject on this forum will be my final test result report, which I expect to complete in Jan 2016.
Cullen's paper concerning radiation pressure measurements on the end plate of a waveguide are not directly relevant to the EM Drive because the EM Drive is a completely closed resonant cavity (as per Shawyer's "theory"). Cullen's statement pertains to a waveguide that is closed at one end and open at the other end. The resonance of a closed cavity is different from the resonance of an open waveguide. See a number of undergraduate textbooks: Balanis, Collin, Fano, etc.
If you wish to apply Cullen's paper methodology to the EM Drive, you would need to open one end of the EM Drive (but if you do so, you will have to be even more concerned with safety, as the microwave field will be open to escape at the open end -see my previous message regarding the death of monkeys exposed to 100 watts of microwave power).
Also, the whole controversy with Shawyer's EM Drive has to do with the violation of the principle of conservation of momentum if a closed resonating cavity were capable of self-acceleration (without using any external fields) as proposed by Shawyer's "theory".
Cullen's experimental measurements on open waveguides (unlike Shawyer's EM Drive "theory") do NOT violate the principle of conservation of momentum. Cullen became a Professor at a University, Cullen's experiments were wholly consistent with Maxwell's equations and with classical physics.
_______
PS: thank you for your kind invitation to that other forum, but I think it is best to have these discussions at NASA SpaceFlight forum, the home of the free and the brave. NSF's very wide viewership is a counterbalance to the "groupthink" https://en.wikipedia.org/wiki/Groupthink that small forums are prone to have because they lack the "critical mass" of large viewership. :) -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: X_RaY on 12/13/2015 04:54 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456770#msg1456770">Quote from: TheTraveller on 12/13/2015 03:52 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456747#msg1456747">Quote from: Rodal on 12/13/2015 03:29 PM</a>
states that the Magnetron will excite a transverse ELECTRIC mode for a CYLINDRICAL cavity TE013
The drawing states nothing about the excited mode, only that the frustum has a TE013 resonance at 2.449 GHz as per my EmDrive Design spreadsheet, which has it's resonance predictions match with those of SPR's in house system to +-0.5%
As TE013 and TM113 have the same guide wavelength and frustum resonance in this model, using the magnetron's 1/4 wave stub antenna in the centre of the big end plate will excite the TM113 resonant mode and not the TE013 mode.
Cullen 15 makes it clear that radiation pressure on a end plate in a waveguide is not directly dependent on excited mode but instead is dependent on guide wavelength, which can be effected by excited mode.
If you wish to continue this conversation please join the EmDriveResearch forum as the next comment I make on this subject on this forum will be my final test result report, which I expect to complete in Jan 2016.
@TT
The degenerated state of the TE01p/TM11p is only true for cylindrical cavities (based on the same value of the corresponding Bessel value). If my memory is correct, EMPro showed a mode seperation of these two shapes in a frustrum like cavity resonator. I will recheck this next days if I find the time to do this.
EDIT:
Frank Davies file show what I mean. Please look especially to TE012 and TM112. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: X_RaY on 12/13/2015 05:36 PM -
"... to that other forum, but I think it is best to have these discussions at NASA SpaceFlight forum, the home of the free and the brave. "
Glad you stay here Doc :) don't switch to the dark side of the force ;D ;) -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/13/2015 05:37 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456795#msg1456795">Quote from: X_RaY on 12/13/2015 04:54 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456770#msg1456770">Quote from: TheTraveller on 12/13/2015 03:52 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456747#msg1456747">Quote from: Rodal on 12/13/2015 03:29 PM</a>
states that the Magnetron will excite a transverse ELECTRIC mode for a CYLINDRICAL cavity TE013
The drawing states nothing about the excited mode, only that the frustum has a TE013 resonance at 2.449 GHz as per my EmDrive Design spreadsheet, which has it's resonance predictions match with those of SPR's in house system to +-0.5%
As TE013 and TM113 have the same guide wavelength and frustum resonance in this model, using the magnetron's 1/4 wave stub antenna in the centre of the big end plate will excite the TM113 resonant mode and not the TE013 mode.
Cullen 15 makes it clear that radiation pressure on a end plate in a waveguide is not directly dependent on excited mode but instead is dependent on guide wavelength, which can be effected by excited mode.
If you wish to continue this conversation please join the EmDriveResearch forum as the next comment I make on this subject on this forum will be my final test result report, which I expect to complete in Jan 2016.
The degenerate state of the TE01p/TM11p is true for cylindrical cavities (based on the same value of the corresponding Bessel value). I my memory is correct, EMPro showed a mode seperation of these two shapes in a frustrum like cavity resonator. I will recheck this next days if I find the time to do this.
EDIT:
Frank Davies file show what I mean. Please look especially to TE012 and TM112.
Frank Davis shows in his frustum of a cone analysis, on page 12, for what he labels as TM112 mode shape ( 1.9355 GHz ):
RED vectors= Electric field
BLUE vectors= Electric fieldQuote"TM112" Note: like TM110 at top, and TM111 at bottom
where he is referring to what mode shapes TM110 and TM111 look like for a cylindrical cavity.
______________
TE012 mode shape (2.1794 GHz) on page 18 looks close to what mode shape TE012 looks like in a cylindrical cavity
______________
What is labeled as TM113 (2.2730 GHz) on page 20 has a little complicated Electric field (red) near the top.QuoteNote: intense fields at top
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: X_RaY on 12/13/2015 05:49 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456812#msg1456812">Quote from: Rodal on 12/13/2015 05:37 PM</a>
Jep I got the same indication problems while specify the right shape for some of the modes. Also my spreadsheet is not able to predict all of them correctly in comparison with FEM since it is based on formula for cylindrical cavities. That's why I switched to FEM analysis.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456795#msg1456795">Quote from: X_RaY on 12/13/2015 04:54 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456770#msg1456770">Quote from: TheTraveller on 12/13/2015 03:52 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456747#msg1456747">Quote from: Rodal on 12/13/2015 03:29 PM</a>states that the Magnetron will excite a transverse ELECTRIC mode for a CYLINDRICAL cavity TE013
The drawing states nothing about the excited mode, only that the frustum has a TE013 resonance at 2.449 GHz as per my EmDrive Design spreadsheet, which has it's resonance predictions match with those of SPR's in house system to +-0.5%
As TE013 and TM113 have the same guide wavelength and frustum resonance in this model, using the magnetron's 1/4 wave stub antenna in the centre of the big end plate will excite the TM113 resonant mode and not the TE013 mode.
Cullen 15 makes it clear that radiation pressure on a end plate in a waveguide is not directly dependent on excited mode but instead is dependent on guide wavelength, which can be effected by excited mode.
If you wish to continue this conversation please join the EmDriveResearch forum as the next comment I make on this subject on this forum will be my final test result report, which I expect to complete in Jan 2016.
The degenerate state of the TE01p/TM11p is true for cylindrical cavities (based on the same value of the corresponding Bessel value). I my memory is correct, EMPro showed a mode seperation of these two shapes in a frustrum like cavity resonator. I will recheck this next days if I find the time to do this.
EDIT:
Frank Davies file show what I mean. Please look especially to TE012 and TM112.
Frank Davis shows in his frustum of a cone analysis, on page 12, for what he labels as TM112 mode shape ( 1.9355 GHz ):Quote"TM112" Note: like TM110 at top, and TM111 at bottom
where he is referring to what mode shapes TM110 and TM111 look like for a cylindrical cavity.
______________
TE012 mode shape (2.1794 GHz) on page 18 looks close to what mode shape TE012 looks like in a cylindrical cavity
______________
What is labeled as TM113 (2.2730 GHz) on page 20 looks a little complicated.QuoteNote: intense fields at top
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SeeShells on 12/13/2015 05:52 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456811#msg1456811">Quote from: X_RaY on 12/13/2015 05:36 PM</a>
"... to that other forum, but I think it is best to have these discussions at NASA SpaceFlight forum, the home of the free and the brave. "
Glad you stay here Doc :) don't switch to the dark side of the force ;D ;)
He stays here because we have cookies. ;D
Shell -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/13/2015 05:55 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456816#msg1456816">Quote from: SeeShells on 12/13/2015 05:52 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456811#msg1456811">Quote from: X_RaY on 12/13/2015 05:36 PM</a>
"... to that other forum, but I think it is best to have these discussions at NASA SpaceFlight forum, the home of the free and the brave. "
Glad you stay here Doc :) don't switch to the dark side of the force ;D ;)
He stays here because we have cookies. ;D
Shell
and Shell :) -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: OnlyMe on 12/13/2015 05:57 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456795#msg1456795">Quote from: X_RaY on 12/13/2015 04:54 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456770#msg1456770">Quote from: TheTraveller on 12/13/2015 03:52 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456747#msg1456747">Quote from: Rodal on 12/13/2015 03:29 PM</a>
states that the Magnetron will excite a transverse ELECTRIC mode for a CYLINDRICAL cavity TE013
The drawing states nothing about the excited mode, only that the frustum has a TE013 resonance at 2.449 GHz as per my EmDrive Design spreadsheet, which has it's resonance predictions match with those of SPR's in house system to +-0.5%
As TE013 and TM113 have the same guide wavelength and frustum resonance in this model, using the magnetron's 1/4 wave stub antenna in the centre of the big end plate will excite the TM113 resonant mode and not the TE013 mode.
Cullen 15 makes it clear that radiation pressure on a end plate in a waveguide is not directly dependent on excited mode but instead is dependent on guide wavelength, which can be effected by excited mode.
If you wish to continue this conversation please join the EmDriveResearch forum as the next comment I make on this subject on this forum will be my final test result report, which I expect to complete in Jan 2016.
The degenerate state of the TE01p/TM11p is true for cylindrical cavities (based on the same value of the corresponding Bessel value). I my memory is correct, EMPro showed a mode seperation of these two shapes in a frustrum like cavity resonator. I will recheck this next days if I find the time to do this.
EDIT:
Frank Davies file show what I mean. Please look especially to TE012 and TM112.
Don't the actual dimensions of the frustum affect how the different modes are manifest in a particular frustum?
If so, how does this information have any direct connection to a frustum of different dimensions?
I guess what I am asking is, if you cannot use conclusions drawn from a cylindrical cavity to determine modes in a tapered cavity, how can you expect results from one tapered cavity to apply to another tapered cavity of very different dimensions?
It seems to me that before any conclusions drawn from Davies file could be used as general reference, it would need to include a series of different cavity dimensions and just how those dimensional changes affect mode distribution... -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: X_RaY on 12/13/2015 06:01 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456818#msg1456818">Quote from: OnlyMe on 12/13/2015 05:57 PM</a>
We have done a lot of FEM simulations with different cone dimensions...<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456795#msg1456795">Quote from: X_RaY on 12/13/2015 04:54 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456770#msg1456770">Quote from: TheTraveller on 12/13/2015 03:52 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456747#msg1456747">Quote from: Rodal on 12/13/2015 03:29 PM</a>states that the Magnetron will excite a transverse ELECTRIC mode for a CYLINDRICAL cavity TE013
The drawing states nothing about the excited mode, only that the frustum has a TE013 resonance at 2.449 GHz as per my EmDrive Design spreadsheet, which has it's resonance predictions match with those of SPR's in house system to +-0.5%
As TE013 and TM113 have the same guide wavelength and frustum resonance in this model, using the magnetron's 1/4 wave stub antenna in the centre of the big end plate will excite the TM113 resonant mode and not the TE013 mode.
Cullen 15 makes it clear that radiation pressure on a end plate in a waveguide is not directly dependent on excited mode but instead is dependent on guide wavelength, which can be effected by excited mode.
If you wish to continue this conversation please join the EmDriveResearch forum as the next comment I make on this subject on this forum will be my final test result report, which I expect to complete in Jan 2016.
The degenerate state of the TE01p/TM11p is true for cylindrical cavities (based on the same value of the corresponding Bessel value). I my memory is correct, EMPro showed a mode seperation of these two shapes in a frustrum like cavity resonator. I will recheck this next days if I find the time to do this.
EDIT:
Frank Davies file show what I mean. Please look especially to TE012 and TM112.
Don't the actual dimensions of the frustum affect how the different modes are manifest in a particular frustum?
If so, how does this information have any direct connection to a frustum of different dimensions?
I guess what I am asking is, if you cannot use conclusions drawn from a cylindrical cavity to determine modes in a tapered cavity, how can you expect results from one tapered cavity to apply to another tapered cavity of very different dimensions?
It seems to me that before any conclusions drawn from Davies file could be used as general reference, it would need to include a series of different cavity dimensions and just how those dimensional changes affect mode distribution...
The NASA also.
And at least I have build and studied a large number of different conical cavities inclusive measurements via VNA (K-Band ~24 GHz).
Follow the curves of TE011 and TM111
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/13/2015 06:05 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456818#msg1456818">Quote from: OnlyMe on 12/13/2015 05:57 PM</a>
Not following the general norm for experimental reports (where geometrical dimensions of tested objects are usually provided by the authors), Shawyer failed to report all the geometrical dimensions of the Demonstrator EM Drive (and of other EM Drives he has reported).<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456795#msg1456795">Quote from: X_RaY on 12/13/2015 04:54 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456770#msg1456770">Quote from: TheTraveller on 12/13/2015 03:52 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456747#msg1456747">Quote from: Rodal on 12/13/2015 03:29 PM</a>states that the Magnetron will excite a transverse ELECTRIC mode for a CYLINDRICAL cavity TE013
The drawing states nothing about the excited mode, only that the frustum has a TE013 resonance at 2.449 GHz as per my EmDrive Design spreadsheet, which has it's resonance predictions match with those of SPR's in house system to +-0.5%
As TE013 and TM113 have the same guide wavelength and frustum resonance in this model, using the magnetron's 1/4 wave stub antenna in the centre of the big end plate will excite the TM113 resonant mode and not the TE013 mode.
Cullen 15 makes it clear that radiation pressure on a end plate in a waveguide is not directly dependent on excited mode but instead is dependent on guide wavelength, which can be effected by excited mode.
If you wish to continue this conversation please join the EmDriveResearch forum as the next comment I make on this subject on this forum will be my final test result report, which I expect to complete in Jan 2016.
The degenerate state of the TE01p/TM11p is true for cylindrical cavities (based on the same value of the corresponding Bessel value). I my memory is correct, EMPro showed a mode seperation of these two shapes in a frustrum like cavity resonator. I will recheck this next days if I find the time to do this.
EDIT:
Frank Davies file show what I mean. Please look especially to TE012 and TM112.
Don't the actual dimensions of the frustum affect how the different modes are manifest in a particular frustum?
If so, how does this information have any direct connection to a frustum of different dimensions?
I guess what I am asking is, if you cannot use conclusions drawn from a cylindrical cavity to determine modes in a tapered cavity, how can you expect results from one tapered cavity to apply to another tapered cavity of very different dimensions?
It seems to me that before any conclusions drawn from Davies file could be used as general reference, it would need to include a series of different cavity dimensions and just how those dimensional changes affect mode distribution...
As shown in the post by X-Ray (immediately above this post), Frank Davis did such an analysis to try to ascertain the geometry (given two dimensions, exploring the whole range of dimensions for the missing dimension) and mode shape present in Shawyer's purported Demonstration EM Drive experiments (since Mr. Shawyer did not either provide experimental confirmation of what mode shape -if any- was excited in his reported experiments, nor did he provide all of the geometrical dimensions).
Frank Davis (NASA) analysis in this regard is outstanding (way superior to anything ever reported by Shawyer or Yang). However, the graphical analysis (discussed in previous threads) was limited to frequency, as a discussion of different mode shapes electromagnetic vector fields (including images for all of them) for different geometries would entail a huge amount of data to publish. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rq3 on 12/13/2015 06:20 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456505#msg1456505">Quote from: TheTraveller on 12/12/2015 10:11 PM</a>
Update on my latest build.
Cutting copper next week. Using a 1.2kW Panasonic maggie, driven by a modified Panasonic maggie inverter power supply. Will be using a 5kv vac switch to remove filament power once the maggie is generating microwaves. Expect 1st Force measurements early Jan 2016.
Report back then.
The filament runs at only a few volts, (usually 3 to5) which "floats" on the high voltage, but many (usually 10-20) amps. Also, unless your "inverter" is actually tightly regulated, the peak voltage may be pushing 10,000 volts prior to the magnetron starting.
Ya'll be safe out there. You're allowed exactly one mistake with a magnetron power supply. There are no second chances, only a funeral. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: ThereIWas3 on 12/13/2015 06:29 PM -
My previous report on the meep analysis of SeeShell's project turns out to have a tiny error in the resonant frequency. Through an accident of math, the number printed out by the 'harminv' function of meep looks an awful lot like a frequency in GHz, but it is not. It is the frequency in "meep frequency units", which are scaled by a/c where 'a' is an arbitarary scale factor to make units convenient (consistent throughout all runs) and 'c' is the speed of light in m/s. Since in this case a=0.3 and c is just a hair under 300,000,000, the scaled number comes out looking resonable, until you notice that it in the wrong range by a factor of almost exactly 1E9.
So the corrected figure is 2.494 GHz, not 2.4959 GHz.
I am adding code to the meep program to automatically correct for this and print out the resonance analysis in real-world units. Edit: though a small error now, if we should later choose to change the 'a' scale factor for some reason, results could be considerably off without this correction. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SteveD on 12/13/2015 07:03 PM - I might be able to spend some time over the holidays putting together the library section of the rfdriven website, if anyone is interested.
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SeeShells on 12/13/2015 07:51 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456836#msg1456836">Quote from: SteveD on 12/13/2015 07:03 PM</a>
I might be able to spend some time over the holidays putting together the library section of the rfdriven website, if anyone is interested.
You're welcome to link or use my images of the build. I'll have more to post.
http://s1039.photobucket.com/user/shells2bells2002/library/CE%20Electromagnetic%20Reaction%20Thruster?sort=3&page=1
Shell -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: ThinkerX on 12/13/2015 09:43 PM -
Quote
I might be able to spend some time over the holidays putting together the library section of the rfdriven website, if anyone is interested.
Perhaps a link to the 'rfdriven' site on page 1, post 1 of this thread is in order? Or will be soon?
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: aero on 12/13/2015 11:26 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456827#msg1456827">Quote from: ThereIWas3 on 12/13/2015 06:29 PM</a>
My previous report on the meep analysis of SeeShell's project turns out to have a tiny error in the resonant frequency. Through an accident of math, the number printed out by the 'harminv' function of meep looks an awful lot like a frequency in GHz, but it is not. It is the frequency in "meep frequency units", which are scaled by a/c where 'a' is an arbitarary scale factor to make units convenient (consistent throughout all runs) and 'c' is the speed of light in m/s. Since in this case a=0.3 and c is just a hair under 300,000,000, the scaled number comes out looking resonable, until you notice that it in the wrong range by a factor of almost exactly 1E9.
So the corrected figure is 2.494 GHz, not 2.4959 GHz.
I am adding code to the meep program to automatically correct for this and print out the resonance analysis in real-world units. Edit: though a small error now, if we should later choose to change the 'a' scale factor for some reason, results could be considerably off without this correction.
The Harminv output is produced, separated by commas, so you can simply copy and paste it from the terminal into your spreadsheet as csv, then add a column to convert by (c/a). Then your spreadsheet maintains a readable record of all of your resonance runs which is quite handy when you need to refer back to a run you made last week. Just make sure that you annotate each run data set so that you can properly identify it after you've forgotten all about it next week. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: aero on 12/14/2015 12:38 AM -
Question for you antenna experts out there: "How wide is the gap between the close ends of the 1/4 wavelength dipoles used to construct a 1/2 wavelength antenna in the T configuration?"
See .gif attached. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rfmwguy on 12/14/2015 01:10 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456890#msg1456890">Quote from: ThinkerX on 12/13/2015 09:43 PM</a>
Good idea...doneQuote
I might be able to spend some time over the holidays putting together the library section of the rfdriven website, if anyone is interested.
Perhaps a link to the 'rfdriven' site on page 1, post 1 of this thread is in order? Or will be soon? -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SeeShells on 12/14/2015 01:22 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456957#msg1456957">Quote from: aero on 12/14/2015 12:38 AM</a>
Question for you antenna experts out there: "How wide is the gap between the close ends of the 1/4 wavelength dipoles used to construct a 1/2 wavelength antenna in the T configuration?"
see gif attached
See .gif attached.
(
)
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: aero on 12/14/2015 01:42 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456967#msg1456967">Quote from: SeeShells on 12/14/2015 01:22 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456957#msg1456957">Quote from: aero on 12/14/2015 12:38 AM</a>
Question for you antenna experts out there: "How wide is the gap between the close ends of the 1/4 wavelength dipoles used to construct a 1/2 wavelength antenna in the T configuration?"
see gif attached
See .gif attached.
()
Thanks Shell - but in the real world of hardware, how far apart are the two vertical feeds leading to the close ends of the 1/4 wl dipoles? Is it really just a half wl wire fed in the center so in reality there is no gap? The graphic doesn't appear to imply that. What is shown in the pink and blue? voltage and current? certainly not RF fields. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SteveD on 12/14/2015 01:44 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456967#msg1456967">Quote from: SeeShells on 12/14/2015 01:22 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456957#msg1456957">Quote from: aero on 12/14/2015 12:38 AM</a>
Question for you antenna experts out there: "How wide is the gap between the close ends of the 1/4 wavelength dipoles used to construct a 1/2 wavelength antenna in the T configuration?"
see gif attached
See .gif attached.
()
That's showing the total length. I think what Aero was asking is how large the gap in the middle should be. Could you, for example, make the dipoles of the T 1/16 of a wavelength long and have a large gap of empty space between the two ends? -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SeeShells on 12/14/2015 02:29 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456971#msg1456971">Quote from: SteveD on 12/14/2015 01:44 AM</a>
I remember tuning a Dipole when I was in school (yes we had electricity then) and made the area between the two tunable with a pair of screws. I remember that a 1/10 WL worked the best. I did a search on the net to find something and there was nothing that jumped out at me to answer the question.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456967#msg1456967">Quote from: SeeShells on 12/14/2015 01:22 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456957#msg1456957">Quote from: aero on 12/14/2015 12:38 AM</a>Question for you antenna experts out there: "How wide is the gap between the close ends of the 1/4 wavelength dipoles used to construct a 1/2 wavelength antenna in the T configuration?"
see gif attached
See .gif attached.
()
That's showing the total length. I think what Aero was asking is how large the gap in the middle should be. Could you, for example, make the dipoles of the T 1/16 of a wavelength long and have a large gap of empty space between the two ends?
Shell
BTW it the Magnetic and electrical field you're looking at. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rfmwguy on 12/14/2015 02:39 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456971#msg1456971">Quote from: SteveD on 12/14/2015 01:44 AM</a>
Not sure this 1/2 wave dipole will work in a cavity. Normally this would only be used when an rf ground plane were not present. Think of the ham operator stringing up a dipole between a couple of trees.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456967#msg1456967">Quote from: SeeShells on 12/14/2015 01:22 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456957#msg1456957">Quote from: aero on 12/14/2015 12:38 AM</a>Question for you antenna experts out there: "How wide is the gap between the close ends of the 1/4 wavelength dipoles used to construct a 1/2 wavelength antenna in the T configuration?"
see gif attached
See .gif attached.
()
That's showing the total length. I think what Aero was asking is how large the gap in the middle should be. Could you, for example, make the dipoles of the T 1/16 of a wavelength long and have a large gap of empty space between the two ends?
In our case, the frustum cavity is the ground plane, only a quarter wave resonator need be present...just like in a magnetron.
To your question of spacing, in a 50 ohm system, the spacing is determined by the dielectric material of the transmission line...whatever the distance is from the center conductor to the braid (in the case of common coax) is all that is needed.
Here's a bunch of stuff related to a center fed dipole:
https://en.m.wikipedia.org/wiki/Dipole_antenna -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SeeShells on 12/14/2015 03:00 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456985#msg1456985">Quote from: rfmwguy on 12/14/2015 02:39 AM</a>
That's like 75 ohm?<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456971#msg1456971">Quote from: SteveD on 12/14/2015 01:44 AM</a>
Not sure this 1/2 wave dipole will work in a cavity. Normally this would only be used when an rf ground plane were not present. Think of the ham operator stringing up a dipole between a couple of trees.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456967#msg1456967">Quote from: SeeShells on 12/14/2015 01:22 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456957#msg1456957">Quote from: aero on 12/14/2015 12:38 AM</a>Question for you antenna experts out there: "How wide is the gap between the close ends of the 1/4 wavelength dipoles used to construct a 1/2 wavelength antenna in the T configuration?"
see gif attached
See .gif attached.
()
That's showing the total length. I think what Aero was asking is how large the gap in the middle should be. Could you, for example, make the dipoles of the T 1/16 of a wavelength long and have a large gap of empty space between the two ends?
In our case, the frustum cavity is the ground plane, only a quarter wave resonator need be present...just like in a magnetron.
To your question of spacing, in a 50 ohm system, the spacing is determined by the dielectric material of the transmission line...whatever the distance is from the center conductor to the braid (in the case of common coax) is all that is needed.
http://www.csgnetwork.com/antennaedcalc.html -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SeeShells on 12/14/2015 03:04 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456985#msg1456985">Quote from: rfmwguy on 12/14/2015 02:39 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456971#msg1456971">Quote from: SteveD on 12/14/2015 01:44 AM</a>
Not sure this 1/2 wave dipole will work in a cavity. Normally this would only be used when an rf ground plane were not present. Think of the ham operator stringing up a dipole between a couple of trees.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456967#msg1456967">Quote from: SeeShells on 12/14/2015 01:22 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456957#msg1456957">Quote from: aero on 12/14/2015 12:38 AM</a>Question for you antenna experts out there: "How wide is the gap between the close ends of the 1/4 wavelength dipoles used to construct a 1/2 wavelength antenna in the T configuration?"
see gif attached
See .gif attached.
()
That's showing the total length. I think what Aero was asking is how large the gap in the middle should be. Could you, for example, make the dipoles of the T 1/16 of a wavelength long and have a large gap of empty space between the two ends?
In our case, the frustum cavity is the ground plane, only a quarter wave resonator need be present...just like in a magnetron.
To your question of spacing, in a 50 ohm system, the spacing is determined by the dielectric material of the transmission line...whatever the distance is from the center conductor to the braid (in the case of common coax) is all that is needed.
Here's a bunch of stuff related to a center fed dipole:
https://en.m.wikipedia.org/wiki/Dipole_antenna
The kicker is the frustum shouldn't be acting like a ground plane for the antenna as the mode generation nodes are different. This is what Dr. Rodal was talking about many pages ago and I'd agree with him. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rfmwguy on 12/14/2015 03:07 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456990#msg1456990">Quote from: SeeShells on 12/14/2015 03:00 AM</a>
If you have parallel wires leading towards the dipole launch, air would be the dielectric and used to calculate spacing to maintain 50 ohms match.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456985#msg1456985">Quote from: rfmwguy on 12/14/2015 02:39 AM</a>
That's like 75 ohm?<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456971#msg1456971">Quote from: SteveD on 12/14/2015 01:44 AM</a>
Not sure this 1/2 wave dipole will work in a cavity. Normally this would only be used when an rf ground plane were not present. Think of the ham operator stringing up a dipole between a couple of trees.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456967#msg1456967">Quote from: SeeShells on 12/14/2015 01:22 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456957#msg1456957">Quote from: aero on 12/14/2015 12:38 AM</a>Question for you antenna experts out there: "How wide is the gap between the close ends of the 1/4 wavelength dipoles used to construct a 1/2 wavelength antenna in the T configuration?"
see gif attached
See .gif attached.
()
That's showing the total length. I think what Aero was asking is how large the gap in the middle should be. Could you, for example, make the dipoles of the T 1/16 of a wavelength long and have a large gap of empty space between the two ends?
In our case, the frustum cavity is the ground plane, only a quarter wave resonator need be present...just like in a magnetron.
To your question of spacing, in a 50 ohm system, the spacing is determined by the dielectric material of the transmission line...whatever the distance is from the center conductor to the braid (in the case of common coax) is all that is needed.
http://www.csgnetwork.com/antennaedcalc.html
My thought here is the cavity is already at rf ground potential, so another radiator in the can would not be useful...dead weight so to speak -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rfmwguy on 12/14/2015 03:11 AM -
Interesting thought about frustum not being at rf ground potential. Are you planning to isolate signal source ground and frustum ground?
If you are, this will be very interesting. Im not sure I've ever read about a cavity being above rf ground potential...just another example of trying something new...no problem with that -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: aero on 12/14/2015 03:20 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456982#msg1456982">Quote from: SeeShells on 12/14/2015 02:29 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456971#msg1456971">Quote from: SteveD on 12/14/2015 01:44 AM</a>
I remember tuning a Dipole when I was in school (yes we had electricity then) and made the area between the two tunable with a pair of screws. I remember that a 1/10 WL worked the best. I did a search on the net to find something and there was nothing that jumped out at me to answer the question.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456967#msg1456967">Quote from: SeeShells on 12/14/2015 01:22 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456957#msg1456957">Quote from: aero on 12/14/2015 12:38 AM</a>Question for you antenna experts out there: "How wide is the gap between the close ends of the 1/4 wavelength dipoles used to construct a 1/2 wavelength antenna in the T configuration?"
see gif attached
See .gif attached.
()
That's showing the total length. I think what Aero was asking is how large the gap in the middle should be. Could you, for example, make the dipoles of the T 1/16 of a wavelength long and have a large gap of empty space between the two ends?
Shell
BTW it the Magnetic and electrical field you're looking at.
hmm 1/10 wl is 1.2 cm isn't it? That seems like a pretty large gap but I'll run it and see. I've been running 1 - 2 mm which is more like the radius of a common coax. But then, what is the diameter of the coax used for 2.5 GHz? Wikipedia gives a range from very small to over 6 inches in diameter. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SeeShells on 12/14/2015 03:22 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456996#msg1456996">Quote from: rfmwguy on 12/14/2015 03:07 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456990#msg1456990">Quote from: SeeShells on 12/14/2015 03:00 AM</a>
If you have parallel wires leading towards the dipole launch, air would be the dielectric and used to calculate spacing to maintain 50 ohms match.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456985#msg1456985">Quote from: rfmwguy on 12/14/2015 02:39 AM</a>
That's like 75 ohm?<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456971#msg1456971">Quote from: SteveD on 12/14/2015 01:44 AM</a>
Not sure this 1/2 wave dipole will work in a cavity. Normally this would only be used when an rf ground plane were not present. Think of the ham operator stringing up a dipole between a couple of trees.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456967#msg1456967">Quote from: SeeShells on 12/14/2015 01:22 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456957#msg1456957">Quote from: aero on 12/14/2015 12:38 AM</a>Question for you antenna experts out there: "How wide is the gap between the close ends of the 1/4 wavelength dipoles used to construct a 1/2 wavelength antenna in the T configuration?"
see gif attached
See .gif attached.
()
That's showing the total length. I think what Aero was asking is how large the gap in the middle should be. Could you, for example, make the dipoles of the T 1/16 of a wavelength long and have a large gap of empty space between the two ends?
In our case, the frustum cavity is the ground plane, only a quarter wave resonator need be present...just like in a magnetron.
To your question of spacing, in a 50 ohm system, the spacing is determined by the dielectric material of the transmission line...whatever the distance is from the center conductor to the braid (in the case of common coax) is all that is needed.
http://www.csgnetwork.com/antennaedcalc.html
My thought here is the cavity is already at rf ground potential, so another radiator in the can would not be useful...dead weight so to speak
Also in this image look at the mode generation. https://drive.google.com/file/d/0B1XizxEfB23tYVNDalhQel9tZ3c/view
If we put an antenna 1/4 from the top or bottom the cavity natural resonance mode generation will not be at the same place as the antenna and cause inter-modal actions decreasing the Q as they build and collapse.
It makes sense to place the antenna center frustum parallel to the bottom in this mode TE013 and for other modes you need to know the mode pattern to properly place if your going to use a dipole.
This way you're adding to the Q not causing a degradation.
Make sense?
Shell
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rfmwguy on 12/14/2015 03:28 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457003#msg1457003">Quote from: SeeShells on 12/14/2015 03:22 AM</a>
Yes...in the meep sims, is the frustum an isolated element, a pure reflector not having an electrical connection to the radiation source? Pardon my meepneptitude ;)<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456996#msg1456996">Quote from: rfmwguy on 12/14/2015 03:07 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456990#msg1456990">Quote from: SeeShells on 12/14/2015 03:00 AM</a>
If you have parallel wires leading towards the dipole launch, air would be the dielectric and used to calculate spacing to maintain 50 ohms match.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456985#msg1456985">Quote from: rfmwguy on 12/14/2015 02:39 AM</a>
That's like 75 ohm?<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456971#msg1456971">Quote from: SteveD on 12/14/2015 01:44 AM</a>
Not sure this 1/2 wave dipole will work in a cavity. Normally this would only be used when an rf ground plane were not present. Think of the ham operator stringing up a dipole between a couple of trees.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456967#msg1456967">Quote from: SeeShells on 12/14/2015 01:22 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456957#msg1456957">Quote from: aero on 12/14/2015 12:38 AM</a>Question for you antenna experts out there: "How wide is the gap between the close ends of the 1/4 wavelength dipoles used to construct a 1/2 wavelength antenna in the T configuration?"
see gif attached
See .gif attached.
()
That's showing the total length. I think what Aero was asking is how large the gap in the middle should be. Could you, for example, make the dipoles of the T 1/16 of a wavelength long and have a large gap of empty space between the two ends?
In our case, the frustum cavity is the ground plane, only a quarter wave resonator need be present...just like in a magnetron.
To your question of spacing, in a 50 ohm system, the spacing is determined by the dielectric material of the transmission line...whatever the distance is from the center conductor to the braid (in the case of common coax) is all that is needed.
http://www.csgnetwork.com/antennaedcalc.html
My thought here is the cavity is already at rf ground potential, so another radiator in the can would not be useful...dead weight so to speak
Also in this image look at the mode generation. https://drive.google.com/file/d/0B1XizxEfB23tYVNDalhQel9tZ3c/view
If we put an antenna 1/4 from the top or bottom the cavity natural resonance mode generation will not be at the same place as the antenna and cause inter-modal actions decreasing the Q as they build and collapse.
It makes sense to place the antenna center frustum parallel to the bottom in this mode TE013 and for other modes you need to know the mode pattern to properly place if your going to use a dipole.
This way you're adding to the Q not causing a degradation.
Make sense?
Shell
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SeeShells on 12/14/2015 03:38 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457005#msg1457005">Quote from: rfmwguy on 12/14/2015 03:28 AM</a>
I believe that is the case in meep, it was one of the issues in modeling the loops.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457003#msg1457003">Quote from: SeeShells on 12/14/2015 03:22 AM</a>
Yes...in the meep sims, is the frustum an isolated element, a pure reflector not having an electrical connection to the radiation source? Pardon my meepneptitude ;)<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456996#msg1456996">Quote from: rfmwguy on 12/14/2015 03:07 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456990#msg1456990">Quote from: SeeShells on 12/14/2015 03:00 AM</a>
If you have parallel wires leading towards the dipole launch, air would be the dielectric and used to calculate spacing to maintain 50 ohms match.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456985#msg1456985">Quote from: rfmwguy on 12/14/2015 02:39 AM</a>
That's like 75 ohm?<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456971#msg1456971">Quote from: SteveD on 12/14/2015 01:44 AM</a>
Not sure this 1/2 wave dipole will work in a cavity. Normally this would only be used when an rf ground plane were not present. Think of the ham operator stringing up a dipole between a couple of trees.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456967#msg1456967">Quote from: SeeShells on 12/14/2015 01:22 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456957#msg1456957">Quote from: aero on 12/14/2015 12:38 AM</a>Question for you antenna experts out there: "How wide is the gap between the close ends of the 1/4 wavelength dipoles used to construct a 1/2 wavelength antenna in the T configuration?"
see gif attached
See .gif attached.
()
That's showing the total length. I think what Aero was asking is how large the gap in the middle should be. Could you, for example, make the dipoles of the T 1/16 of a wavelength long and have a large gap of empty space between the two ends?
In our case, the frustum cavity is the ground plane, only a quarter wave resonator need be present...just like in a magnetron.
To your question of spacing, in a 50 ohm system, the spacing is determined by the dielectric material of the transmission line...whatever the distance is from the center conductor to the braid (in the case of common coax) is all that is needed.
http://www.csgnetwork.com/antennaedcalc.html
My thought here is the cavity is already at rf ground potential, so another radiator in the can would not be useful...dead weight so to speak
Also in this image look at the mode generation. https://drive.google.com/file/d/0B1XizxEfB23tYVNDalhQel9tZ3c/view
If we put an antenna 1/4 from the top or bottom the cavity natural resonance mode generation will not be at the same place as the antenna and cause inter-modal actions decreasing the Q as they build and collapse.
It makes sense to place the antenna center frustum parallel to the bottom in this mode TE013 and for other modes you need to know the mode pattern to properly place if your going to use a dipole.
This way you're adding to the Q not causing a degradation.
Make sense?
Shell
In the real world I'd slap a connector right through the bottom center and feed a coax up to the antenna then branch out horizontally and parallel to the bottom plate with the antenna.
added I'm not a Ham like some here are and antennas are not my cup of tea. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rfmwguy on 12/14/2015 03:53 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457007#msg1457007">Quote from: SeeShells on 12/14/2015 03:38 AM</a>
Got my extra class in 1981 but inactive since the 90s. Trouble is, a connector will make frustum at rf ground potential with a single center conductor. To isolate frustum from signal source, you'll need a triax connector or a dual center conductor if you want rf ground isolation.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457005#msg1457005">Quote from: rfmwguy on 12/14/2015 03:28 AM</a>
I believe that is the case in meep, it was one of the issues in modeling the loops.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457003#msg1457003">Quote from: SeeShells on 12/14/2015 03:22 AM</a>
Yes...in the meep sims, is the frustum an isolated element, a pure reflector not having an electrical connection to the radiation source? Pardon my meepneptitude ;)<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456996#msg1456996">Quote from: rfmwguy on 12/14/2015 03:07 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456990#msg1456990">Quote from: SeeShells on 12/14/2015 03:00 AM</a>
If you have parallel wires leading towards the dipole launch, air would be the dielectric and used to calculate spacing to maintain 50 ohms match.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456985#msg1456985">Quote from: rfmwguy on 12/14/2015 02:39 AM</a>
That's like 75 ohm?<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456971#msg1456971">Quote from: SteveD on 12/14/2015 01:44 AM</a>
Not sure this 1/2 wave dipole will work in a cavity. Normally this would only be used when an rf ground plane were not present. Think of the ham operator stringing up a dipole between a couple of trees.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456967#msg1456967">Quote from: SeeShells on 12/14/2015 01:22 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456957#msg1456957">Quote from: aero on 12/14/2015 12:38 AM</a>Question for you antenna experts out there: "How wide is the gap between the close ends of the 1/4 wavelength dipoles used to construct a 1/2 wavelength antenna in the T configuration?"
see gif attached
See .gif attached.
()
That's showing the total length. I think what Aero was asking is how large the gap in the middle should be. Could you, for example, make the dipoles of the T 1/16 of a wavelength long and have a large gap of empty space between the two ends?
In our case, the frustum cavity is the ground plane, only a quarter wave resonator need be present...just like in a magnetron.
To your question of spacing, in a 50 ohm system, the spacing is determined by the dielectric material of the transmission line...whatever the distance is from the center conductor to the braid (in the case of common coax) is all that is needed.
http://www.csgnetwork.com/antennaedcalc.html
My thought here is the cavity is already at rf ground potential, so another radiator in the can would not be useful...dead weight so to speak
Also in this image look at the mode generation. https://drive.google.com/file/d/0B1XizxEfB23tYVNDalhQel9tZ3c/view
If we put an antenna 1/4 from the top or bottom the cavity natural resonance mode generation will not be at the same place as the antenna and cause inter-modal actions decreasing the Q as they build and collapse.
It makes sense to place the antenna center frustum parallel to the bottom in this mode TE013 and for other modes you need to know the mode pattern to properly place if your going to use a dipole.
This way you're adding to the Q not causing a degradation.
Make sense?
Shell
In the real world I'd slap a connector right through the bottom center and feed a coax up to the antenna then branch out horizontally and parallel to the bottom plate with the antenna.
added I'm not a Ham like some here are and antennas are not my cup of tea.
Watch out for these and make sure they can handle the power and freq. Also, the triax will need a metal case on the outside of the frustum to minimize rf leakage. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SeeShells on 12/14/2015 03:57 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457008#msg1457008">Quote from: rfmwguy on 12/14/2015 03:53 AM</a>
I'm not going with this design hanging the dipole in the center. You are very correct in the mess it could cause. I may end up with a dual loop modified in the small end but haven't made my mind up yet. So far I like the Q and mode generation a waveguide can provide.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457007#msg1457007">Quote from: SeeShells on 12/14/2015 03:38 AM</a>
Got my extra class in 1981 but inactive since the 90s. Trouble is, a connector will make frustum at rf ground potential with a single center conductor. To isolate frustum from signal source, you'll need a triax connector or a dual center conductor if you want rf ground isolation.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457005#msg1457005">Quote from: rfmwguy on 12/14/2015 03:28 AM</a>
I believe that is the case in meep, it was one of the issues in modeling the loops.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457003#msg1457003">Quote from: SeeShells on 12/14/2015 03:22 AM</a>
Yes...in the meep sims, is the frustum an isolated element, a pure reflector not having an electrical connection to the radiation source? Pardon my meepneptitude ;)<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456996#msg1456996">Quote from: rfmwguy on 12/14/2015 03:07 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456990#msg1456990">Quote from: SeeShells on 12/14/2015 03:00 AM</a>
If you have parallel wires leading towards the dipole launch, air would be the dielectric and used to calculate spacing to maintain 50 ohms match.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456985#msg1456985">Quote from: rfmwguy on 12/14/2015 02:39 AM</a>
That's like 75 ohm?<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456971#msg1456971">Quote from: SteveD on 12/14/2015 01:44 AM</a>
Not sure this 1/2 wave dipole will work in a cavity. Normally this would only be used when an rf ground plane were not present. Think of the ham operator stringing up a dipole between a couple of trees.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456967#msg1456967">Quote from: SeeShells on 12/14/2015 01:22 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456957#msg1456957">Quote from: aero on 12/14/2015 12:38 AM</a>Question for you antenna experts out there: "How wide is the gap between the close ends of the 1/4 wavelength dipoles used to construct a 1/2 wavelength antenna in the T configuration?"
see gif attached
See .gif attached.
()
That's showing the total length. I think what Aero was asking is how large the gap in the middle should be. Could you, for example, make the dipoles of the T 1/16 of a wavelength long and have a large gap of empty space between the two ends?
In our case, the frustum cavity is the ground plane, only a quarter wave resonator need be present...just like in a magnetron.
To your question of spacing, in a 50 ohm system, the spacing is determined by the dielectric material of the transmission line...whatever the distance is from the center conductor to the braid (in the case of common coax) is all that is needed.
http://www.csgnetwork.com/antennaedcalc.html
My thought here is the cavity is already at rf ground potential, so another radiator in the can would not be useful...dead weight so to speak
Also in this image look at the mode generation. https://drive.google.com/file/d/0B1XizxEfB23tYVNDalhQel9tZ3c/view
If we put an antenna 1/4 from the top or bottom the cavity natural resonance mode generation will not be at the same place as the antenna and cause inter-modal actions decreasing the Q as they build and collapse.
It makes sense to place the antenna center frustum parallel to the bottom in this mode TE013 and for other modes you need to know the mode pattern to properly place if your going to use a dipole.
This way you're adding to the Q not causing a degradation.
Make sense?
Shell
In the real world I'd slap a connector right through the bottom center and feed a coax up to the antenna then branch out horizontally and parallel to the bottom plate with the antenna.
added I'm not a Ham like some here are and antennas are not my cup of tea.
Watch out for these and make sure they can handle the power and freq. Also, the triax will need a metal case on the ojtside of the frustum to minimize rf leakage.
added
The reason I like the symmetrical waveguide is that you precondition the wave before it hits the frustum cavity instead of letting the asymmetrical cavity determine the radiating pattern from the maggie's antenna or an antenna stuck into the sidewalls or end. ( I've just found it's tough listening to the Best of Nickleback, typing and thinking at the same time. :) )
Shell -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: zen-in on 12/14/2015 04:12 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457008#msg1457008">Quote from: rfmwguy on 12/14/2015 03:53 AM</a>
...pretend there is a gif here
Got my extra class in 1981 but inactive since the 90s. Trouble is, a connector will make frustum at rf ground potential with a single center conductor. To isolate frustum from signal source, you'll need a triax connector or a dual center conductor if you want rf ground isolation.
Watch out for these and make sure they can handle the power and freq. Also, the triax will need a metal case on the outside of the frustum to minimize rf leakage.
Since the body of the magnetron is live with RF any balanced drive would need a balun (to drive the fustrum with a dipole). It would have to be pretty beefy and maybe fed coaxially from the magnetron. This intuitively seem wrong because you really want the fustrum to be at ground potential instead of floating. The magnetron already has a very good 1/4 λ drive (or maybe smaller) sticking out of the business end. The problem is one of matching the impedance of the magnetron drive with the fustrum, no matter what drive is used -balanced or unbalanced. But I think the balanced drive is a lot of trouble and would not work. It should be possible to calculate the impedance of the magnetron drive then design an inline matching network that would match the cavity impedance when 1/4 λ driven. Similar idea as calculating stripline impedances. For example reducing the diameter of the feed increases the impedance. The dielectric surrounding the center conductor would also be a factor. There of course has to be a very good gap-free shield around the center conductor and connecting the magnetron body with the Copper shell of the fustrum.
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SeeShells on 12/14/2015 04:24 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457012#msg1457012">Quote from: zen-in on 12/14/2015 04:12 AM</a>
It is a 1/4 wave out of the maggie, I measured it after pulling one totally apart (DON'T DO THIS IF YOU DON'T KNOW WHAT YOUR DOING ... BIO-HAZARDS) You can attach directly to the antenna right out of the maggie which will give you the maxim power down a coax into a 1/4 wave in a wavegiude on the frustum.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457008#msg1457008">Quote from: rfmwguy on 12/14/2015 03:53 AM</a>
...pretend there is a gif here
Got my extra class in 1981 but inactive since the 90s. Trouble is, a connector will make frustum at rf ground potential with a single center conductor. To isolate frustum from signal source, you'll need a triax connector or a dual center conductor if you want rf ground isolation.
Watch out for these and make sure they can handle the power and freq. Also, the triax will need a metal case on the outside of the frustum to minimize rf leakage.
Since the body of the magnetron is live with RF any balanced drive would need a balun (to drive the fustrum with a dipole). It would have to be pretty beefy and maybe fed coaxially from the magnetron. This intuitively seem wrong because you really want the fustrum to be at ground potential instead of floating. The magnetron already has a very good 1/4 λ drive (or maybe smaller) sticking out of the business end. The problem is one of matching the impedance of the magnetron drive with the fustrum, no matter what drive is used -balanced or unbalanced. But I think the balanced drive is a lot of trouble and would not work. It should be possible to calculate the impedance of the magnetron drive then design an inline matching network that would match the cavity impedance when 1/4 λ driven. Similar idea as calculating stripline impedances. For example reducing the diameter of the feed increases the impedance. The dielectric surrounding the center conductor would also be a factor. There of course has to be a very good gap-free shield around the center conductor and connecting the magnetron body with the Copper shell of the fustrum. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: zen-in on 12/14/2015 04:40 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457016#msg1457016">Quote from: SeeShells on 12/14/2015 04:24 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457012#msg1457012">Quote from: zen-in on 12/14/2015 04:12 AM</a>
It is a 1/4 wave out of the maggie, I measured it after pulling one totally apart (DON'T DO THIS IF YOU DON'T KNOW WHAT YOUR DOING ... BIO-HAZARDS) You can attach directly to the antenna right out of the maggie which will give you the maxim power down a coax into a 1/4 wave in a wavegiude on the frustum.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457008#msg1457008">Quote from: rfmwguy on 12/14/2015 03:53 AM</a>
...pretend there is a gif here
Got my extra class in 1981 but inactive since the 90s. Trouble is, a connector will make frustum at rf ground potential with a single center conductor. To isolate frustum from signal source, you'll need a triax connector or a dual center conductor if you want rf ground isolation.
Watch out for these and make sure they can handle the power and freq. Also, the triax will need a metal case on the outside of the frustum to minimize rf leakage.
Since the body of the magnetron is live with RF any balanced drive would need a balun (to drive the fustrum with a dipole). It would have to be pretty beefy and maybe fed coaxially from the magnetron. This intuitively seem wrong because you really want the fustrum to be at ground potential instead of floating. The magnetron already has a very good 1/4 λ drive (or maybe smaller) sticking out of the business end. The problem is one of matching the impedance of the magnetron drive with the fustrum, no matter what drive is used -balanced or unbalanced. But I think the balanced drive is a lot of trouble and would not work. It should be possible to calculate the impedance of the magnetron drive then design an inline matching network that would match the cavity impedance when 1/4 λ driven. Similar idea as calculating stripline impedances. For example reducing the diameter of the feed increases the impedance. The dielectric surrounding the center conductor would also be a factor. There of course has to be a very good gap-free shield around the center conductor and connecting the magnetron body with the Copper shell of the fustrum.
The problem remains is that going to be a good impedance match. I don't know what impedance the magnetron is suppose to drive. Maybe the tech manuals will say. Using a network analyzer you can measure the input impedance of the fustrum at 2500 MHz when there is a 1/4 λ drive connected to coax. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: ThereIWas3 on 12/14/2015 05:21 AM -
Those GIFs show the traditional balanced feedlline going to a dipole, which is itself balanced. Neither side is grounded. If your signal source is unbalanced (Like most ham transmitters with a coaxial antenna connector, then you need a balanced-to-unbalanced converter, a sort of transformer. This is abbreviated balun. You typically run unbalanced feedline (coaxial cable) out to the antenna, where the balan converts it to a balanced feed at the appropriate impedance to match the dipole at the frequency of interest. If you do not get the impedances correct, you get a reflection, power goes back to the magnetron, heating it.
Cable TV cable is 75 ohms impedance at TV frequencies (100-1000MHz). Ham antennas are usually for HF (3-30MHz) and you use 50 ohm cable. 50 ohms does a better match to the sorts of antennas hams use. (There are other kinds than dipoles.)
Any magnetron taken from an oven is not going to have a coaxial feed on it, nor a balanced connection. Instead it will have an unbalanced probe sticking right out of it which is perhaps coupled by some sort of short waveguide to the oven cavity.
(
)
Shell proposes to use a coaxial connection from the magnetron to the frustrum. For any given type of coax, power loss increases with distance and with frequency. (see chart (http://www.w4rp.com/ref/coax.html)) This coax will basically need a tiny antenna at each end - one to pick up the signal from a small cavity that the magnetron's probe sticks into, and the other one to reradiate the signal into the frustrum. It would be more efficient to use a hard waveguide for this, but at only 2.4 GHz it would be large (3.5" by 1.7" (http://www.microwaves101.com/encyclopedias/rectangular-waveguide-dimensions)) and unwieldly. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: dustinthewind on 12/14/2015 07:12 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457003#msg1457003">Quote from: SeeShells on 12/14/2015 03:22 AM</a>
Also in this image look at the mode generation. https://drive.google.com/file/d/0B1XizxEfB23tYVNDalhQel9tZ3c/view
If we put an antenna 1/4 from the top or bottom the cavity natural resonance mode generation will not be at the same place as the antenna and cause inter-modal actions decreasing the Q as they build and collapse.
It makes sense to place the antenna center frustum parallel to the bottom in this mode TE013 and for other modes you need to know the mode pattern to properly place if your going to use a dipole.
This way you're adding to the Q not causing a degradation.
Make sense?
Shell
I wanted to point out that this image is of the group B-field and not the E-field because the maximum touches the metal walls. This paper here: http://cas.web.cern.ch/cas/Denmark-2010/Lectures/Wolski-2.pdf page 25 they point out that at the metal walls E_tangent=0 and but B_tan doesn't have to be zero. The group electric maximum of light inside the cavity should be at the magnetic nodes which look to be at about 1/4 wavelength (or the empty spots between the magnetic fields).
The antenna then does work against this electric field to store energy in the cavity. I think at mid cavity it might do negative work when trying to inject a signal and store energy in the current in the antenna instead of the cavity. Hopefully I am not too far off here.
P.S. I think it is supposed to be desirable to have the shape of the antenna in the shape of the current flow desired to be generated. Transverse electric/TE being a loop or loops parallel to the plate and TM being vertically orientated loops. This appears to be TM.
I guess your antenna looks about right but I am not sure what it should look like in 3 dimensions. Also to match the magnetic field the current would have to be going in at the same time on both antenna ends unlike in the animated video of the antenna. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/14/2015 02:32 PM -
It is known that
1) the impedance of an antenna in a cavity is significantly different from the impedance of an antenna located in free space. The analysis of antennas in a cavity involves: Green functions, problematic integration of logarithmic singularities, and Galerkin solution methods; and hence more difficult to analyze.
2) it is simpler to couple waveguides by using one or more apertures in the common wall than by coupling waveguides by means of a probe or by means of a loop antenna, or a combination of the two.
3) the theory of coupling waveguides by small apertures was developed by Nobel Prize winner Hans Bethe (his patent: https://docs.google.com/viewer?url=patentimages.storage.googleapis.com/pdfs/US2519734.pdf and his video discussing joining MIT's Radiation Laboratory: http://www.webofstories.com/play/hans.bethe/86;jsessionid=04D1B0A62DF1EE041BBB172D5420BB82 on propagation in waveguides ). The theory is more amenable than the theory of coupling with probes or loops, which entail Galerkin solutions, for example.
4) a number of Meep simulation runs discussed in previous threads show the complications engendered by using a dipole antenna excitation (mainly excitation of very unsymmetric modes and malformed modes) to excite TM modes and even worse for loops trying to excite TE modes (which Meep has shown to be very difficult to excite using loops).
5) Meep simulation runs discussed in previous threads were successful in exciting TE modes by coupling of symmetrically placed waveguides (while Meep excitation of well-formed symmetric TE modes in the frustum of a cone cavity was NOT feasible using loops).
Therefore, why is there so much emphasis on dipoles and direct excitation via magnetrons (the cavity excitation is much more difficult to analyze with them), as opposed to coupling through symmetrically placed waveguides which are easier to analyze and more successful in producing the TE modes that have been promoted by Shawyer and Yang ?
(I am not sympathetic with Shawyer and Yang's "theories", but I don't understand the apparent divergence between Shawyer and Yang's predilection for TE modes vis-a-vis the DIY discussion regarding magnetrons or dipoles or loops which are difficult to analyze and therefore will result in more difficult to predict excitation mode shape of the cavity). Yang (who claims the highest thrust force per input power) has been using coupling through waveguides and Shawyer in his latest papers has also been suggesting coupling through waveguides.
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rfmwguy on 12/14/2015 02:42 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457121#msg1457121">Quote from: Rodal on 12/14/2015 02:32 PM</a>
Cost probably, Doc. Also the rectangular slot(s) are side-injected meaning a new frustum would have to be made if injection point needed to be changed. Hole plugging would be...uhhhh...not cool.
(...)
Therefore, why is there so much emphasis on dipoles and direct excitation via magnetrons, which are much more difficult to analyze, as opposed to coupling through symmetrically placed waveguides which are easier to analyze and more successful in producing the TE modes that have been promoted by Shawyer and Yang ?
(...)
This is coming from an experimenter who didn't spend much time trying to design with a specific mode in mind...mainly because I'm not yet convinced any mode is better than another. It very well MAY be, it wasn't in my game plan to fire off one mode or another.
Part of the process we're going thru is to play around with different techniques and see which one launches thru the roof 8) -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: ThereIWas3 on 12/14/2015 03:21 PM -
I also wonder about the efficacy of trying to inject linearly polarized energy into a cavity that has a circular cross section. That may make sense in a rectangular waveguide, but not a frustrum. Squirting RF in from the sides would seem to me to excite all sorts of wierd patterns within the cavity as well. Did any of the loop excitation attempts put the plane of the loop parallel to the end-plates?
Dipoles are easy to describe in meep, but I would be eager to see what people have come up with for meep models of waveguide injection. Especially since that is what Shawyer used.
Frustrum geometry would make calculation of the impedance very "interesting".
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/14/2015 03:34 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457134#msg1457134">Quote from: ThereIWas3 on 12/14/2015 03:21 PM</a>
... Did any of the loop excitation attempts put the plane of the loop parallel to the end-plates?...
Yes (Meep runs were conducted with the loop parallel to the end-plates, at different locations) -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rfmwguy on 12/14/2015 03:40 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457134#msg1457134">Quote from: ThereIWas3 on 12/14/2015 03:21 PM</a>
I also wonder about the efficacy of trying to inject linearly polarized energy into a cavity that has a circular cross section. That may make sense in a rectangular waveguide, but not a frustrum. Squirting RF in from the sides would seem to me to excite all sorts of wierd patterns within the cavity as well. Did any of the loop excitation attempts put the plane of the loop parallel to the end-plates?
Yes, EW did this...pardon the repeat of an old pic:
Dipoles are easy to describe in meep, but I would be eager to see what people have come up with for meep models of waveguide injection. Especially since that is what Shawyer used.
Frustrum geometry would make calculation of the impedance very "interesting".
https://forum.nasaspaceflight.com/index.php?action=dlattach;topic=38577.0;attach=1080448 -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/14/2015 03:52 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457134#msg1457134">Quote from: ThereIWas3 on 12/14/2015 03:21 PM</a>
I also wonder about the efficacy of trying to inject linearly polarized energy into a cavity that has a circular cross section. That may make sense in a rectangular waveguide, but not a frustrum. Squirting RF in from the sides would seem to me to excite all sorts of wierd patterns within the cavity as well. ...
A bad example that illustrates that problem is Tajmar's experiments at TU Dresden under advice from Shawyer (according to Tajmar's paper), coupling to their small EM Drive with a waveguide with a very large opening (relative to the size of the EM Drive), and furthermore coupling asymmetrically through only one side. This may have resulted in side forces measured in Tajmar's experiments.
(http://forum.nasaspaceflight.com/x478x358xindex.php,,qaction=dlattach,,3Btopic=37642.0,,3Battach=1049935,,3Bimage,Mic.8TrzQQfnoY.webp.pagespeed.ic.40_M5wuK21.webp)
The successful Meep simulation runs were performed using two waveguides coupling symmetrically from opposite sides of the EM Drive, as suggested by Shell. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: oliverio on 12/14/2015 04:08 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457124#msg1457124">Quote from: rfmwguy on 12/14/2015 02:42 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457121#msg1457121">Quote from: Rodal on 12/14/2015 02:32 PM</a>
Cost probably, Doc. Also the rectangular slot(s) are side-injected meaning a new frustum would have to be made if injection point needed to be changed. Hole plugging would be...uhhhh...not cool.
(...)
Therefore, why is there so much emphasis on dipoles and direct excitation via magnetrons, which are much more difficult to analyze, as opposed to coupling through symmetrically placed waveguides which are easier to analyze and more successful in producing the TE modes that have been promoted by Shawyer and Yang ?
(...)
This is coming from an experimenter who didn't spend much time trying to design with a specific mode in mind...mainly because I'm not yet convinced any mode is better than another. It very well MAY be, it wasn't in my game plan to fire off one mode or another.
Part of the process we're going thru is to play around with different techniques and see which one launches thru the roof 8)
I'm throwing my featherlike weight in with your argument that mode generation may indeed not be the most important thing-- at least, stable singular mode generation. I don't have a lot of experience with electromagnetism but I have a decent amount with acoustics; generally, the thing you want out of an acoustic system is high Q, so-to-speak, and resonance is one way to achieve that, but even a high-Q and high-resonance approach will not make for a proper-sounding acoustic system. Much of that is in the details of how the energy in resonance is directed by its container, and if the EMDrive effect thus observed is real, it seems more like that kind of a situation (i.e. "where and what shape should we put the sound-holes on this violin to guarantee stable tones and loud volume?" There is not going to be one vibrational mode generated in a violin, its resonance changes quite tangibly depending on the tone being played, but a nice violin will always play a bright tone with the proper undertones and overtones, which is the combination we want, not necessarily just power reflection and a certain resonance pattern.) -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rfmwguy on 12/14/2015 04:35 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457156#msg1457156">Quote from: oliverio on 12/14/2015 04:08 PM</a>
Good points, Doc and Shell are a step ahead of me regarding why the emdrive has results over the years. Its a bit into the theoretical realm with pointing vectors and the like...for me, it was a brute force thing, an attempt to match impedance and get a resonance set up...sort of an EM "ringing" without knowing what mode forms up.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457124#msg1457124">Quote from: rfmwguy on 12/14/2015 02:42 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457121#msg1457121">Quote from: Rodal on 12/14/2015 02:32 PM</a>
Cost probably, Doc. Also the rectangular slot(s) are side-injected meaning a new frustum would have to be made if injection point needed to be changed. Hole plugging would be...uhhhh...not cool.
(...)
Therefore, why is there so much emphasis on dipoles and direct excitation via magnetrons, which are much more difficult to analyze, as opposed to coupling through symmetrically placed waveguides which are easier to analyze and more successful in producing the TE modes that have been promoted by Shawyer and Yang ?
(...)
This is coming from an experimenter who didn't spend much time trying to design with a specific mode in mind...mainly because I'm not yet convinced any mode is better than another. It very well MAY be, it wasn't in my game plan to fire off one mode or another.
Part of the process we're going thru is to play around with different techniques and see which one launches thru the roof 8)
I'm throwing my featherlike weight in with your argument that mode generation may indeed not be the most important thing-- at least, stable singular mode generation. I don't have a lot of experience with electromagnetism but I have a decent amount with acoustics; generally, the thing you want out of an acoustic system is high Q, so-to-speak, and resonance is one way to achieve that, but even a high-Q and high-resonance approach will not make for a proper-sounding acoustic system. Much of that is in the details of how the energy in resonance is directed by its container, and if the EMDrive effect thus observed is real, it seems more like that kind of a situation (i.e. "where and what shape should we put the sound-holes on this violin to guarantee stable tones and loud volume?" There is not going to be one vibrational mode generated in a violin, its resonance changes quite tangibly depending on the tone being played, but a nice violin will always play a bright tone with the proper undertones and overtones, which is the combination we want, not necessarily just power reflection and a certain resonance pattern.)
Acoustic analysis is related. Parts of a speaker enclosure as well as parts of a musical instrument itself starts complex resonance patterns...you are absolutely correct. Doc and shell might be closing in on something with the modeling. If their thoughts are correct, it will be a great step towards upscaling the effect. We hope... -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Chrochne on 12/14/2015 04:36 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457156#msg1457156">Quote from: oliverio on 12/14/2015 04:08 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457124#msg1457124">Quote from: rfmwguy on 12/14/2015 02:42 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457121#msg1457121">Quote from: Rodal on 12/14/2015 02:32 PM</a>
Cost probably, Doc. Also the rectangular slot(s) are side-injected meaning a new frustum would have to be made if injection point needed to be changed. Hole plugging would be...uhhhh...not cool.
(...)
Therefore, why is there so much emphasis on dipoles and direct excitation via magnetrons, which are much more difficult to analyze, as opposed to coupling through symmerically placed waveguides which are easier to analyze and more successful in producing the TE modes that have been promoted by Shawyer and Yang ?
(...)
This is coming from an experimenter who didn't spend much time trying to design with a specific mode in mind...mainly because I'm not yet convinced any mode is better than another. It very well MAY be, it wasn't in my game plan to fire off one mode or another.
Part of the process we're going thru is to play around with different techniques and see which one launches thru the roof 8)
I'm throwing my featherlike weight in with your argument that mode generation may indeed not be the most important thing-- at least, stable singular mode generation. I don't have a lot of experience with electromagnetism but I have a decent amount with acoustics; generally, the thing you want out of an acoustic system is high Q, so-to-speak, and resonance is one way to achieve that, but even a high-Q and high-resonance approach will not make for a proper-sounding acoustic system. Much of that is in the details of how the energy in resonance is directed by its container, and if the EMDrive effect thus observed is real, it seems more like that kind of a situation (i.e. "where and what shape should we put the sound-holes on this violin to guarantee stable tones and loud volume?" There is not going to be one vibrational mode generated in a violin, its resonance changes quite tangibly depending on the tone being played, but a nice violin will always play a bright tone with the proper undertones and overtones, which is the combination we want, not necessarily just power reflection and a certain resonance pattern.)
Basicaly what you say is that we may need a musician and a scientist that understand music waves and instrument manufacture and also understands all kinds of waves in science to try to understand the emdrive. However, we know from EW tests that they observed thrust in vacuum as well. Still interesting idea :) -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rfmwguy on 12/14/2015 05:00 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457171#msg1457171">Quote from: Chrochne on 12/14/2015 04:36 PM</a>
That's one of the key differences between sound and RF. Sound is a vibration of a medium, such as air. RF only needs a vacuum. Any other medium can attenuate the RF, moist air, liquids, buildings etc.,<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457156#msg1457156">Quote from: oliverio on 12/14/2015 04:08 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457124#msg1457124">Quote from: rfmwguy on 12/14/2015 02:42 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457121#msg1457121">Quote from: Rodal on 12/14/2015 02:32 PM</a>
Cost probably, Doc. Also the rectangular slot(s) are side-injected meaning a new frustum would have to be made if injection point needed to be changed. Hole plugging would be...uhhhh...not cool.
(...)
Therefore, why is there so much emphasis on dipoles and direct excitation via magnetrons, which are much more difficult to analyze, as opposed to coupling through symmerically placed waveguides which are easier to analyze and more successful in producing the TE modes that have been promoted by Shawyer and Yang ?
(...)
This is coming from an experimenter who didn't spend much time trying to design with a specific mode in mind...mainly because I'm not yet convinced any mode is better than another. It very well MAY be, it wasn't in my game plan to fire off one mode or another.
Part of the process we're going thru is to play around with different techniques and see which one launches thru the roof 8)
I'm throwing my featherlike weight in with your argument that mode generation may indeed not be the most important thing-- at least, stable singular mode generation. I don't have a lot of experience with electromagnetism but I have a decent amount with acoustics; generally, the thing you want out of an acoustic system is high Q, so-to-speak, and resonance is one way to achieve that, but even a high-Q and high-resonance approach will not make for a proper-sounding acoustic system. Much of that is in the details of how the energy in resonance is directed by its container, and if the EMDrive effect thus observed is real, it seems more like that kind of a situation (i.e. "where and what shape should we put the sound-holes on this violin to guarantee stable tones and loud volume?" There is not going to be one vibrational mode generated in a violin, its resonance changes quite tangibly depending on the tone being played, but a nice violin will always play a bright tone with the proper undertones and overtones, which is the combination we want, not necessarily just power reflection and a certain resonance pattern.)
Basicaly what you say is that we may need a musician and a scientist that understand music waves and instrument manufacture and also understands all kinds of waves in science to try to understand the emdrive. However, we know from EW tests that they observed thrust in vacuum as well. Still interesting idea :)
Now, the big questions is what does the vacuum consist of to be able to be a "perfect" medium for electromagnetic waves? Aether or empty? Now, that gets a lot of discussions started. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SeeShells on 12/14/2015 05:17 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457034#msg1457034">Quote from: dustinthewind on 12/14/2015 07:12 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457003#msg1457003">Quote from: SeeShells on 12/14/2015 03:22 AM</a>
Also in this image look at the mode generation. https://drive.google.com/file/d/0B1XizxEfB23tYVNDalhQel9tZ3c/view
If we put an antenna 1/4 from the top or bottom the cavity natural resonance mode generation will not be at the same place as the antenna and cause inter-modal actions decreasing the Q as they build and collapse.
It makes sense to place the antenna center frustum parallel to the bottom in this mode TE013 and for other modes you need to know the mode pattern to properly place if your going to use a dipole.
This way you're adding to the Q not causing a degradation.
Make sense?
Shell
I wanted to point out that this image is of the group B-field and not the E-field because the maximum touches the metal walls. This paper here: http://cas.web.cern.ch/cas/Denmark-2010/Lectures/Wolski-2.pdf page 25 they point out that at the metal walls E_tangent=0 and but B_tan doesn't have to be zero. The group electric maximum of light inside the cavity should be at the magnetic nodes which look to be at about 1/4 wavelength (or the empty spots between the magnetic fields).
The antenna then does work against this electric field to store energy in the cavity. I think at mid cavity it might do negative work when trying to inject a signal and store energy in the current in the antenna instead of the cavity. Hopefully I am not too far off here.
P.S. I think it is supposed to be desirable to have the shape of the antenna in the shape of the current flow desired to be generated. Transverse electric/TE being a loop or loops parallel to the plate and TM being vertically orientated loops. This appears to be TM.
I guess your antenna looks about right but I am not sure what it should look like in 3 dimensions. Also to match the magnetic field the current would have to be going in at the same time on both antenna ends unlike in the animated video of the antenna.
One of my fav songs Dustinthewind... 8) I would agree with you but to see what is really happening you need to look at the frustum in X,Y and Z slices and tell me how many modes of operation do you see. https://drive.google.com/drive/folders/0B1XizxEfB23tbVYwc1Nsa29yZlk
I think it's a good time to quickly summarize some of what we have done in the last 6 months inserting RF energy into the frustum.
Loops and antennas inside if the frustum can be problematic in the placing, we have seen it with meep and some real world tests. Even if you consider magnetron direct injection it's a 1/4 wave snub antenna into the bottom or top or sides. What your asking the asymmetrical cavity to do is act as the launcher and produce high energy, high Q modes.
TE modes which have shown by some evidence to produce the greatest thrusts are hard to produce with a single dipole, snub or even a loop antenna. I believe this is one reason the Chinese, Shawyer, NASA EagleWorks, Tajmar have elected to go to a waveguide insertion. Late this summer after hundreds of hours of aero and others running simulations and Dr. Rodal offering his unparalleled expertise it became clear that the placement of antennas was problematic to sustain a good Q and a non-interactive decaying modes within the frustum.
Dipoles when placed 1/4 WL, parallel to the endplates will tend to want to excite a TM mode and if the cavity for the frequency was designed for a TE mode for the frequency you could get 2+ interacting modes TEs and TMs or a combination of both. Now this depends on the cavity dimensions (look at Davies's mode chart and this is for just one base size and one set length) and incoming frequency and where the resonate modes cross paths.
https://drive.google.com/drive/folders/0B1XizxEfB23tbVYwc1Nsa29yZlk was done with a 30MHz bandwidth and even then you can see multi mode generations in the frustum. The interesting thin is when aero reduced the bandwidth ~200 hz the Q dropped to very little and the energy inside of the frustum was quite small. For some reason and I'm still looking into the why the extra modes when driven by a relatively non-interfering waveguide into the frustum increased the Q several orders of magnitude.
I wished I knew what Davies used for his modeling of the resonate wavechart. Then we could match the best preforming frustums (at this time it's waveguide insertion) to the different sizes. One thing I gleaned from looking at the chart is the frustum being injected with a 2.45GHz (top yellow oval Band Width oval) and how many modes interacted. Interesting to note here why did Davies only plot out and label the TE modes?
Need another cup of coffee and will write more later.
Shell -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/14/2015 05:19 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457180#msg1457180">Quote from: rfmwguy on 12/14/2015 05:00 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457171#msg1457171">Quote from: Chrochne on 12/14/2015 04:36 PM</a>
That's one of the key differences between sound and RF. Sound is a vibration of a medium, such as air. RF only needs a vacuum. Any other medium can attenuate the RF, moist air, liquids, buildings etc.,<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457156#msg1457156">Quote from: oliverio on 12/14/2015 04:08 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457124#msg1457124">Quote from: rfmwguy on 12/14/2015 02:42 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457121#msg1457121">Quote from: Rodal on 12/14/2015 02:32 PM</a>
Cost probably, Doc. Also the rectangular slot(s) are side-injected meaning a new frustum would have to be made if injection point needed to be changed. Hole plugging would be...uhhhh...not cool.
(...)
Therefore, why is there so much emphasis on dipoles and direct excitation via magnetrons, which are much more difficult to analyze, as opposed to coupling through symmerically placed waveguides which are easier to analyze and more successful in producing the TE modes that have been promoted by Shawyer and Yang ?
(...)
This is coming from an experimenter who didn't spend much time trying to design with a specific mode in mind...mainly because I'm not yet convinced any mode is better than another. It very well MAY be, it wasn't in my game plan to fire off one mode or another.
Part of the process we're going thru is to play around with different techniques and see which one launches thru the roof 8)
I'm throwing my featherlike weight in with your argument that mode generation may indeed not be the most important thing-- at least, stable singular mode generation. I don't have a lot of experience with electromagnetism but I have a decent amount with acoustics; generally, the thing you want out of an acoustic system is high Q, so-to-speak, and resonance is one way to achieve that, but even a high-Q and high-resonance approach will not make for a proper-sounding acoustic system. Much of that is in the details of how the energy in resonance is directed by its container, and if the EMDrive effect thus observed is real, it seems more like that kind of a situation (i.e. "where and what shape should we put the sound-holes on this violin to guarantee stable tones and loud volume?" There is not going to be one vibrational mode generated in a violin, its resonance changes quite tangibly depending on the tone being played, but a nice violin will always play a bright tone with the proper undertones and overtones, which is the combination we want, not necessarily just power reflection and a certain resonance pattern.)
Basicaly what you say is that we may need a musician and a scientist that understand music waves and instrument manufacture and also understands all kinds of waves in science to try to understand the emdrive. However, we know from EW tests that they observed thrust in vacuum as well. Still interesting idea :)
Now, the big questions is what does the vacuum consist of to be able to be a "perfect" medium for electromagnetic waves? Aether or empty? Now, that gets a lot of discussions started.
Well, we may start by someone giving an example of a completely closed acoustic cavity that can experience self-acceleration (as claimed for the EM Drive). I don't know of any such case. Acoustic tapered cavities don't experience self acceleration, one can show that the momentum in such a completely enclosed cavity is self-cancelling.
The trombone and other wind instruments selected as examples in previous discussions are akin to open waveguides, not to completely closed cavities.
Ditto for a loudspeaker: you will not be able to to hear a loudspeaker located inside a completely enclosed cavity that does not let any air in and out of the enclosure, if you are outside the enclosure. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Flyby on 12/14/2015 05:20 PM -
Somewhat related to the waveguide topic...
As I was trying to figure out the schematics of the tubing and plumbing on Shawyer's rotating rig, I noticed the waveguide feeding the frustum has either a strange extension to it, or enters the frustum at a different spot i first thought...
My initial thought was that the waveguide fed into the frustum at the top.... now I'm not so sure anymore.
and what are those shiny connectors doing on the black waveguide just above the frustum (pic1)?
also, notice the strange brass knobs at the bottom of pic2, on/in the waveguide. They make me think of Yang's adjusting screws....
any thoughts on all that???
Both pictures show a slightly different version. I suspect the rig of pic1 is a further evolution of the one we see in pic2, because it has additional plumbing and cooling radiators. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/14/2015 05:32 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457185#msg1457185">Quote from: SeeShells on 12/14/2015 05:17 PM</a>
...
I wished I knew what Davies used for his modeling of the resonate wavechart. Then we could match the best preforming frustums (at this time it's waveguide insertion) to the different sizes. One thing I gleaned from looking at the chart is the frustum being injected with a 2.45GHz (top yellow oval Band Width oval) and how many modes interacted. Interesting to note here why did Davies only plot out and label the TE modes?
Need another cup of coffee and will write more later.
Shell
I think that Frank Davis' analysis (at NASA, using COMSOL Finite Element analysis) is an eigenvalue analysis, it is not a transient response analysis due to a particular excitation (*). No excitation of any kind is modeled in an eigenvalue analysis. As such, the eigenvalue analysis just gives the eigenvalues at which resonance occurs.
Think, for example, of the resonance of a string (clamped at both ends). One can perform an eigenvalue analysis (for a given length of the string, knowing its modulus of elasticity and its density, and the cross-sectional area of the string) which will give the resonant response of the string. Such eigenvalue analysis for the resonant response of the string tells you just that: the eigenvalues at which resonance can occur.
(
)
It does not say what will happen if you play the string instrument by plucking the string at a particular place with a particular excitation. To know that one has to perform a force-response analysis (either using mode analysis for linear problems or using a transient response analysis for general problems).
__________
(*) The Meep analyses run by aero have been transient response analyses. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SeeShells on 12/14/2015 05:32 PM -
CLIPPED down...<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457121#msg1457121">Quote from: Rodal on 12/14/2015 02:32 PM</a>It is known that
Much better said than what I rambled on about but the same conclusions can be drawn.
(I am not sympathetic with Shawyer and Yang's "theories", but I don't understand the apparent divergence between Shawyer and Yang's predilection for TE modes vis-a-vis the DIY discussion regarding magnetrons or dipoles or loops which are difficult to analyze and therefore will result in more difficult to predict excitation mode shape of the cavity). Yang (who claims the highest thrust force per input power) has been using coupling through waveguides and Shawyer in his latest papers has also been suggesting coupling through waveguides.
Well said Dr. Rodal, well said.
Shell -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: oliverio on 12/14/2015 05:34 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457189#msg1457189">Quote from: Rodal on 12/14/2015 05:19 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457180#msg1457180">Quote from: rfmwguy on 12/14/2015 05:00 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457171#msg1457171">Quote from: Chrochne on 12/14/2015 04:36 PM</a>
That's one of the key differences between sound and RF. Sound is a vibration of a medium, such as air. RF only needs a vacuum. Any other medium can attenuate the RF, moist air, liquids, buildings etc.,<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457156#msg1457156">Quote from: oliverio on 12/14/2015 04:08 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457124#msg1457124">Quote from: rfmwguy on 12/14/2015 02:42 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457121#msg1457121">Quote from: Rodal on 12/14/2015 02:32 PM</a>
Cost probably, Doc. Also the rectangular slot(s) are side-injected meaning a new frustum would have to be made if injection point needed to be changed. Hole plugging would be...uhhhh...not cool.
(...)
Therefore, why is there so much emphasis on dipoles and direct excitation via magnetrons, which are much more difficult to analyze, as opposed to coupling through symmerically placed waveguides which are easier to analyze and more successful in producing the TE modes that have been promoted by Shawyer and Yang ?
(...)
This is coming from an experimenter who didn't spend much time trying to design with a specific mode in mind...mainly because I'm not yet convinced any mode is better than another. It very well MAY be, it wasn't in my game plan to fire off one mode or another.
Part of the process we're going thru is to play around with different techniques and see which one launches thru the roof 8)
I'm throwing my featherlike weight in with your argument that mode generation may indeed not be the most important thing-- at least, stable singular mode generation. I don't have a lot of experience with electromagnetism but I have a decent amount with acoustics; generally, the thing you want out of an acoustic system is high Q, so-to-speak, and resonance is one way to achieve that, but even a high-Q and high-resonance approach will not make for a proper-sounding acoustic system. Much of that is in the details of how the energy in resonance is directed by its container, and if the EMDrive effect thus observed is real, it seems more like that kind of a situation (i.e. "where and what shape should we put the sound-holes on this violin to guarantee stable tones and loud volume?" There is not going to be one vibrational mode generated in a violin, its resonance changes quite tangibly depending on the tone being played, but a nice violin will always play a bright tone with the proper undertones and overtones, which is the combination we want, not necessarily just power reflection and a certain resonance pattern.)
Basicaly what you say is that we may need a musician and a scientist that understand music waves and instrument manufacture and also understands all kinds of waves in science to try to understand the emdrive. However, we know from EW tests that they observed thrust in vacuum as well. Still interesting idea :)
Now, the big questions is what does the vacuum consist of to be able to be a "perfect" medium for electromagnetic waves? Aether or empty? Now, that gets a lot of discussions started.
Well, we may start by someone giving an example of a completely closed acoustic cavity that can experience self-acceleration (as claimed for the EM Drive). I don't know of any such case. Acoustic tapered cavities don't experience self acceleration, one can show that the momentum in such a completely enclosed cavity is self-cancelling.
The trombone and other wind instruments selected as examples in previous discussions are akin to open waveguides, not to completely closed cavities.
Ditto for a loudspeaker: you will not be able to to hear a loudspeaker located inside a completely enclosed cavity that does not let any air in and out of the enclosure, if you are outside the enclosure.
On the contrary, my fine doctor friend, I think I can point out a clear example that is unfortunately just a bit too close to some hackneyed theories that have been thrown about on this thread, but I'll suggest it anyway.
Say that you took a very light cavity of resonant wood, and enclose within it an acoustic speaker; this cavity is shaped like a very short, wide rectangle, but perhaps with one sideplate shorter than the other sideplate. (A rectangular frustrum?) Place this object against a surface.
I contend that due to doppler shift, given the right dimensions, one side of the rectangle will clearly vibrate at a higher frequency as is the case when one hears a loud noise in an enclosed room (it sounds higher pitched than if you had been in a larger room). I contend as well that this object would slide across a surface with the right frictional coefficient, with an orientation dependent upon the rectangular frustrum's orientation, the pitch, and mode excited within.
Correct me on the thought experiment but I'm pretty sure that is all within the confines of well-understood physics (it's a vibrational motor, right? An oscillator or something is what I seem to recall the terminology being.) Is it not the case that this might work as a vague analogue (read: very vague, for I am not trying to say that the vibrational friction of an EMDrive propels it anywhere) for the way that an EMDrive might "push" against space without propelling itself? -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/14/2015 05:40 PM -
The motion on a frictional surface is well-understood (through both experiments, theoretical and numerical analysis). It is due to stick-slip friction and the nonlinear characteristic of the frictional law (multilinear if you want, including the fact that the slding frictional coefficient is usually smaller than the static friction coefficient) .
In this case what is proposed for the EM Drive (by Shawyer and others) is that it can result in self-acceleration in space without the influence of any fields or outside forces. (No friction between the EM Drive spaceship and the vacuum).
Do you know of any self-enclosed acoustic cavity that can experience self-acceleration in space, without the influence of any fields or outside forces ? -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SeeShells on 12/14/2015 05:49 PM -
That says it very clear to me. The only thing that is in a frustum cavity that also is on the outside is Spacetime. If we are to assume that nothing can get out to produce thrust it has to be something that permeates inside of the frustum fro the outside. That's the QV of space, that is even present in a black hole, nothing escapes QV and Spacetime. The question is simple how do we interact with it inside of this can of microwaves? The answer is the tough part.
Shell
added: I once said give me a hole and I'll give you thrust but I've finally settled on that this is truly a enclosed frame and there is no hole. It is the one thing that permeates through the drive and that is the QV of spacetime. I can see why Dr. White is pushing his theories of the production of Virtual Particles from the device but that has several things in it's theory that have come under question (better people than me at QED theories). I'm left with the stinging question of why has EagleWorks seen a time differential in their laser inferometer test and even in the hackaday mini drive seems to show something weird.
Shell
Corrected missspellings sorry someone chatting at me and a cat on my keyboard saying love me, way to much input for good output. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: ThereIWas3 on 12/14/2015 06:24 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457208#msg1457208">Quote from: SeeShells on 12/14/2015 05:49 PM</a>
added: I once said give me a hole and I'll give you thrust but I've finally settled on that this is truly a enclosed frame and there is no hole.
There is no hole in the 3 dimensions you can see. Perhaps the hole is where you are not looking? Gee, I hope this does not involve m-branes. All we need is string-theorists getting involved. :) -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: oliverio on 12/14/2015 06:28 PM -
Yes. I think you and the rest of us are all on to some part of the theory but there's no way that we're going to actually solve the problem without more experimental results (nudge nudge hint hint [I kid, take your time ;p]).
If I had a stronger background in the required maths I would be trying to do some work figuring out some of the more burning questions, but I have to content myself with armchair analytics for now. Personally I think Bohmian mechanics could mathematically model an EMDrive just fine, but in that regard I really lack on the background maths, but without the maths, I am content to say that I think you're barking up the right tree. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: oliverio on 12/14/2015 06:31 PM - This somewhat disingenuously ignores the several well-formulated descriptions of a spacetime medium which can receive and impart momentum (see any number of superfluidic theories about spacetime with which we are all familiar; I'm not saying any of these are correct but they are reasonable given further evidence, which is enough to lend them credibility for discussion in speculative physics).
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rfmwguy on 12/14/2015 06:40 PM -
OK, Aether, the immutable vacuum of space, the zero point field, quantum vacuum, the ground state...all these terms are floating around. However, the LHC discovery of the higgs-boson is regenerating some Aether talk...this one mathematician calls it "Electron Jelly" and puts it in layman's terms. Log this hypothesis as a 21st century Aether discussion:
"In the parts of space where the jelly is calm, we measure a vacuum. But where there are ripples in the jelly, we measure an electron."
https://plus.maths.org/content/particle-hunting-lhc-particles
Perhaps a "ghostly" medium (quantum fields) exists all around us as a natural part of nature. Perhaps the LHC is the best experimental platform to provide this evidence. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SeeShells on 12/14/2015 06:47 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457221#msg1457221">Quote from: ThereIWas3 on 12/14/2015 06:24 PM</a>
The only thing from the outside that's also inside of the frustum is...<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457208#msg1457208">Quote from: SeeShells on 12/14/2015 05:49 PM</a>added: I once said give me a hole and I'll give you thrust but I've finally settled on that this is truly a enclosed frame and there is no hole.
There is no hole in the 3 dimensions you can see. Perhaps the hole is where you are not looking? Gee, I hope this does not involve m-branes. All we need is string-theorists getting involved. :) -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/14/2015 06:49 PM -
You have not provided any experimental evidence that any object (particularly a self-enclosed acoustic cavity) can experience self-acceleration in contradiction with the principle of conservation of momentum (without relying on external fields, forces or expelling mass or energy).
Astrophysical observations have not revealed any object in the Cosmos who experience such self-acceleration in contradiction to the principle of conservation of momentum (particularly a self-enclosed acoustic cavity).
________
PS: Your accusation of being "somewhat disingeneous" is out of place. Characterizing somebody else's remarks is uncalled for. Just discussion of the facts will do. ;)
I was simply answering rfmwguy's call for discussion. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: OnlyMe on 12/14/2015 06:58 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457235#msg1457235">Quote from: SeeShells on 12/14/2015 06:47 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457221#msg1457221">Quote from: ThereIWas3 on 12/14/2015 06:24 PM</a>
The only thing from the outside that's also inside of the frustum is...<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457208#msg1457208">Quote from: SeeShells on 12/14/2015 05:49 PM</a>added: I once said give me a hole and I'll give you thrust but I've finally settled on that this is truly a enclosed frame and there is no hole.
There is no hole in the 3 dimensions you can see. Perhaps the hole is where you are not looking? Gee, I hope this does not involve m-branes. All we need is string-theorists getting involved. :)
Gravity... Because the ground state of the vacuum inside is not determined by the ground state outside, just as the EM modes between two plates is not determined by the modes outside the gap.
PS. Once you turn the EMDrive on there is no longer a vacuum ground state inside.
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/14/2015 06:59 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457242#msg1457242">Quote from: OnlyMe on 12/14/2015 06:58 PM</a>
That is one of the possibilities (using a particular version of GR) discussed by Notsosureofit who is Ph.D. in physics that has worked in this domain some time ago (and we are lucky to have in these threads from time to time). :)<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457235#msg1457235">Quote from: SeeShells on 12/14/2015 06:47 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457221#msg1457221">Quote from: ThereIWas3 on 12/14/2015 06:24 PM</a>
The only thing from the outside that's also inside of the frustum is...<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457208#msg1457208">Quote from: SeeShells on 12/14/2015 05:49 PM</a>added: I once said give me a hole and I'll give you thrust but I've finally settled on that this is truly a enclosed frame and there is no hole.
There is no hole in the 3 dimensions you can see. Perhaps the hole is where you are not looking? Gee, I hope this does not involve m-branes. All we need is string-theorists getting involved. :)
Gravity... Because the ground state of the vacuum inside is not determined by the ground state outside, just as the EM modes between two plates is not determined by the modes outside the gap.
Analysis of the EM Drive using standard General Relativity (GR) (not the version discussed by Notsosureofit) in a previous thread revealed effects that are several orders of magnitude smaller than what is claimed by EM Drive experimenters -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: OnlyMe on 12/14/2015 07:05 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457244#msg1457244">Quote from: Rodal on 12/14/2015 06:59 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457242#msg1457242">Quote from: OnlyMe on 12/14/2015 06:58 PM</a>
That is one of the possibilities (using a particular version of GR) discussed by Notsosureofit who is Ph.D. in physics that has worked in this domain (and we are lucky to have in these threads from time to time). :)<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457235#msg1457235">Quote from: SeeShells on 12/14/2015 06:47 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457221#msg1457221">Quote from: ThereIWas3 on 12/14/2015 06:24 PM</a>
The only thing from the outside that's also inside of the frustum is...<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457208#msg1457208">Quote from: SeeShells on 12/14/2015 05:49 PM</a>added: I once said give me a hole and I'll give you thrust but I've finally settled on that this is truly a enclosed frame and there is no hole.
There is no hole in the 3 dimensions you can see. Perhaps the hole is where you are not looking? Gee, I hope this does not involve m-branes. All we need is string-theorists getting involved. :)
Gravity... Because the ground state of the vacuum inside is not determined by the ground state outside, just as the EM modes between two plates is not determined by the modes outside the gap.
Analysis of the EM Drive using standard General Relativity (GR) (not the version discussed by Notsosureofit) in a previous thread revealed effects that are several orders of magnitude smaller than what is claimed by EM Drive experimenters
Even if gravity or inertia is involved, I see no way that it can begin from the macroscopic approach of GR. It really seems to me that if there is a persistently confirmed thrust, it has to originate as a quantum effect, or quasi-classical quantum effect. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: oliverio on 12/14/2015 07:06 PM -
I'm not sure why you're hammering this in. My point goes like this:
Acoustic resonance can, steady-state-like, push against a solid medium and accelerate.
There may be a spacetime continuum against which objects can push.
Therefore there may be an EMDrive that, in similar steadystate fashion, pushes against some spacetime.
(If you disagree with the validity of this argument, you're plainly mistaken. If you disagree with its content, I agree with you on some levels. I'm skeptical.)
I'm not saying that's what the EMDrive does or that any acoustic resonating chamber violates the conservation of momentum. I think you might have me confused with someone whose posts don't need to be read, because I clearly specified that I wasn't suggesting any such thing. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: dustinthewind on 12/14/2015 07:09 PM -
I found particularly interesting one mode posted by Shell before that had what appeared to be a traveling mode. It had dual input wave-guides and a mode that appeared at the bottom and then traveled up. I was wondering if a mode such as that might be difficult to generate with an antenna. I am not sure if it was but I suspected an asymmetry. What would be desired is an asymmetry of force on the cavity. Warptech pointed out to me in a video https://www.youtube.com/watch?v=ZqC3AVcuFaE that David states if they used a dielectric between the elements that it wouldn't get propulsion unless it was water. If water would be pushed in the opposite direction as propulsion via the electro-magnetic fields and water has a dielectric constant then I believe space also has a permittivity. One could then possibly think of space as being the water and it is being pushed in the opposite direction as propulsion. If space as a dielectric was indeed being pushed one would have to ask if it could be pushed through the cavity walls. I also question if a stable mode is what is really desired to be generated. Maybe that is why some success has been achieved with magnetrons. I think one can think of a gradient in the dielectric constant of free space as an effect of gravity leading to gravitational lensing. A gap between two plates with the casimir force, where radiation is lacking, may also possibly be thought of as differences in the dielectric constant of space between and outside the plates which would correspond to energy density.
Some ideas that come to mind are the Dynamical Casimir Effect: https://goo.gl/A5jUd6
Something interesting I found on the effect of gravity on the dielectric constant of space and gravity slowing down light and or dragging space: https://goo.gl/oZxyvB P.S. I don't think we can detect locally this change in the speed of light because distance contracts with light slowing down so effectively it dosn't change speed locally, only non-locally). One of the reasons why I am not sure LIGO will be able to detect gravity waves but maybe I don't know enough about it.
Here is a paper I found on (asymmetric, anti-symmetric, symmetric modes) generated by light on cavities: https://goo.gl/tTf0Ap
I'll attach an image of one of my hope in generating such an asymmetry. The idea behind it is normally the electric and magnetic force oppose each other in a phased array antenna but with counter-winding of the phased array antennas the interaction of the magnetic field can be reversed so that the effect of charge separation works with the magnetic effects. The only problem being how to achieve such currents in wires at microwave wavelengths. Maybe why Transverse electric effects are so successful in the frustum is because (if it works) it avoids charge separation in the frustum so that the magnetic effects don't work against the electric charge separation in the cavity walls.
If we can say the cavity is some how pushing on space time then maybe we can avoid the whole CoM issue. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SeeShells on 12/14/2015 07:09 PM -
Let's think about it differently (you know me... kinda of weird thinking) from a different perspective.
What would it take to move a object from one point in space to another without changing it's mass by increasing or decreasing it. I can't do it? Why not? Nature did it very easy during the inflationary period of the universe. (
)
Yes this is like the Alcubierre warp drive.
If we take away everything that doesn't make sense in this being a very closed system and what your left with is this thought. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SeeShells on 12/14/2015 07:49 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457257#msg1457257">Quote from: rfmwguy on 12/14/2015 07:20 PM</a>
Where EW got themselves hammered last year was a claim made in the press that their thruster violated newton's laws (of conservation). For us regular folk, this is akin to saying there is no supreme being. A lot of people will come after you frothing at the mouth with pitchforks and torches.
This is no theory but just looking at things that stand out from some simple questions and facts we know.
As best we know right now, there has been no experimental evidence of CoM violations...ever. On the other hand, there is no evidence that all of the emdrive tests are system-wide measurement errors. Its speculation from afar...rather safe and mundane analysis.
For me personally, tho I cannot yet put forward a theory, I think there is something being repulsed or expelled (or a combination of both). Non-detectable matter or fields are the usual suspects, and that's fine, but somewhere down the road we're going to have to call it what we think it is.
p.s. There "ain't no way" I'm going to speculate on what it is...not yet. We either believe it works or we don't...or better yet...keep our minds open.
I'm moving operations into the area I've set aside in my home. I'll post more later.
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/14/2015 08:02 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457249#msg1457249">Quote from: oliverio on 12/14/2015 07:06 PM</a>
...
I'm not sure why you're hammering this in. My point goes like this:
Acoustic resonance can, steady-state-like, push against a solid medium and accelerate.
There may be a spacetime continuum against which objects can push.
Therefore there may be an EMDrive that, in similar steadystate fashion, pushes against some spacetime.
(If you disagree with the validity of this argument, you're plainly mistaken. If you disagree with its content, I agree with you on some levels. I'm skeptical.)
I'm not saying that's what the EMDrive does or that any acoustic resonating chamber violates the conservation of momentum. I think you might have me confused with someone whose posts don't need to be read, because I clearly specified that I wasn't suggesting any such thing.
OK, point well taken . If the argument is "pushing against spacetime", the counter-arguments, instead, then deal with frame-indifference and conservation of energy, previously discussed by Frobnicat and DeltaMass. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/14/2015 08:10 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457250#msg1457250">Quote from: dustinthewind on 12/14/2015 07:09 PM</a>
...I found particularly interesting one mode posted by Shell before that had what appeared to be a traveling mode. It had dual input wave-guides and a mode that appeared at the bottom and then traveled up. I was wondering if a mode such as that might be difficult to generate with an antenna. I am not sure if it was but I suspected an asymmetry. What would be desired is an asymmetry of force on the cavity. Warptech pointed out to me in a video https://www.youtube.com/watch?v=ZqC3AVcuFaE that David states if they used a dielectric between the elements that it wouldn't get propulsion unless it was water. If water would be pushed in the opposite direction as propulsion via the electro-magnetic fields and water has a dielectric constant then I believe space also has a permittivity. One could then possibly think of space as being the water and it is being pushed in the opposite direction as propulsion. If space as a dielectric was indeed being pushed one would have to ask if it could be pushed through the cavity walls. I also question if a stable mode is what is really desired to be generated. Maybe that is why some success has been achieved with magnetrons. I think one can think of a gradient in the dielectric constant of free space as an effect of gravity leading to gravitational lensing. A gap between two plates with the casimir force, where radiation is lacking, may also possibly be thought of as differences in the dielectric constant of space between and outside the plates which would correspond to energy density.
Some ideas that come to mind are the Dynamical Casimir Effect: https://goo.gl/A5jUd6
Something interesting I found on the effect of gravity on the dielectric constant of space and gravity slowing down light and or dragging space: https://goo.gl/oZxyvB P.S. I don't think we can detect locally this change in the speed of light because distance contracts with light slowing down so effectively it dosn't change speed locally, only non-locally). One of the reasons why I am not sure LIGO will be able to detect gravity waves but maybe I don't know enough about it.
Here is a paper I found on (asymmetric, anti-symmetric, symmetric modes) generated by light on cavities: https://goo.gl/tTf0Ap
I'll attach an image of one of my hope in generating such an asymmetry. The idea behind it is normally the electric and magnetic force oppose each other in a phased array antenna but with counter-winding of the phased array antennas the interaction of the magnetic field can be reversed so that the effect of charge separation works with the magnetic effects. The only problem being how to achieve such currents in wires at microwave wavelengths. Maybe why Transverse electric effects are so successful in the frustum is because (if it works) it avoids charge separation in the frustum so that the magnetic effects don't work against the electric charge separation in the cavity walls.
If we can say the cavity is some how pushing on space time then maybe we can avoid the whole CoM issue.
OK, but then the proponents need to address the objections based on frame-indifference (is there a privileged frame? which frame? and why?) and conservation of energy, previously discussed by Frobnicat and DeltaMass. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: qraal on 12/14/2015 08:46 PM - The question of how the Drive works is interesting, but there's one concern I have. If the EM-Drive or Q-Thruster works as Sonny White imagines, as a vacuum plasma thruster, then it's a "space propeller" or "space-jet", which treats the vacuum as a propulsive medium. When the medium is water or air, both have speed limitations because of drag against the medium they're interacting with. What's the equivalent for a space-time propeller/jet? What kind of drag will such a drive encounter?
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: oliverio on 12/14/2015 08:52 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457275#msg1457275">Quote from: Rodal on 12/14/2015 08:10 PM</a>
...
OK, but then the proponents need to address the objections based on frame-indifference (is there a privileged frame? which frame? and why?) and conservation of energy, previously discussed by Frobnicat and DeltaMass.
We already know that frame-dragging exists, and it is a very small effect (i.e. if spacetime is a fluid of some sort, it is necessarily very slippery), but famous experiments like the GP-B give a lot of weight to the idea that spacetime can be warped in more ways than we yet quite understand, given that the hypothetical medium is fundamentally difficult to quantify and observe.
As far as a privileged frame of reference goes, I think Bohmian mechanics does a good job of biting that bullet. You can reconstruct relativistic physics just fine inside of a system that does have a privileged frame of reference, and if this is the case, Einstein still wasn't wrong. He didn't deny the idea that there could be a privileged frame of reference, actually.
"The aether of the general theory of relativity is a medium without mechanical and kinematic properties, but which codetermines mechanical and electromagnetic events." - Einstein (Source, Pais, "Subtle is the Lord" p 313.)
Reference https://www.physicsforums.com/threads/did-einstein-accept-the-ether.4021/ -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: oliverio on 12/14/2015 08:53 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457295#msg1457295">Quote from: qraal on 12/14/2015 08:46 PM</a>
The question of how the Drive works is interesting, but there's one concern I have. If the EM-Drive or Q-Thruster works as Sonny White imagines, as a vacuum plasma thruster, then it's a "space propeller" or "space-jet", which treats the vacuum as a propulsive medium. When the medium is water or air, both have speed limitations because of drag against the medium they're interacting with. What's the equivalent for a space-time propeller/jet? What kind of drag will such a drive encounter?
It will encounter drag against spacetime just the same. There's a number of possible results I think. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: dustinthewind on 12/14/2015 09:01 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457275#msg1457275">Quote from: Rodal on 12/14/2015 08:10 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457250#msg1457250">Quote from: dustinthewind on 12/14/2015 07:09 PM</a>
...I found particularly interesting one mode posted by Shell before that had what appeared to be a traveling mode. It had dual input wave-guides and a mode that appeared at the bottom and then traveled up. I was wondering if a mode such as that might be difficult to generate with an antenna. I am not sure if it was but I suspected an asymmetry. What would be desired is an asymmetry of force on the cavity. Warptech pointed out to me in a video https://www.youtube.com/watch?v=ZqC3AVcuFaE that David states if they used a dielectric between the elements that it wouldn't get propulsion unless it was water. If water would be pushed in the opposite direction as propulsion via the electro-magnetic fields and water has a dielectric constant then I believe space also has a permittivity. One could then possibly think of space as being the water and it is being pushed in the opposite direction as propulsion. If space as a dielectric was indeed being pushed one would have to ask if it could be pushed through the cavity walls. I also question if a stable mode is what is really desired to be generated. Maybe that is why some success has been achieved with magnetrons. I think one can think of a gradient in the dielectric constant of free space as an effect of gravity leading to gravitational lensing. A gap between two plates with the casimir force, where radiation is lacking, may also possibly be thought of as differences in the dielectric constant of space between and outside the plates which would correspond to energy density.
Some ideas that come to mind are the Dynamical Casimir Effect: https://goo.gl/A5jUd6
Something interesting I found on the effect of gravity on the dielectric constant of space and gravity slowing down light and or dragging space: https://goo.gl/oZxyvB P.S. I don't think we can detect locally this change in the speed of light because distance contracts with light slowing down so effectively it dosn't change speed locally, only non-locally). One of the reasons why I am not sure LIGO will be able to detect gravity waves but maybe I don't know enough about it.
Here is a paper I found on (asymmetric, anti-symmetric, symmetric modes) generated by light on cavities: https://goo.gl/tTf0Ap
I'll attach an image of one of my hope in generating such an asymmetry. The idea behind it is normally the electric and magnetic force oppose each other in a phased array antenna but with counter-winding of the phased array antennas the interaction of the magnetic field can be reversed so that the effect of charge separation works with the magnetic effects. The only problem being how to achieve such currents in wires at microwave wavelengths. Maybe why Transverse electric effects are so successful in the frustum is because (if it works) it avoids charge separation in the frustum so that the magnetic effects don't work against the electric charge separation in the cavity walls.
If we can say the cavity is some how pushing on space time then maybe we can avoid the whole CoM issue.
OK, but then the proponents need to address the objections based on frame-indifference (is there a privileged frame? which frame? and why?) and conservation of energy, previously discussed by Frobnicat and DeltaMass.
I am not sure it would work but one might consider the preferred frame at the edge of an event horzion as moving at the speed of light and as such light can't escape. That is if gravity actually drags space time for some reason. Problem is that suggests light going into the black hole could non-locally exceed the speed of light. I would think rather light should slow down near the event horizon till it comes to a stand-still. Maybe this makes sense if the non-local space is moving at the speed of light into the event horizon and that the light in that space, as a result, is time dilated and there fore, stands still. Maybe then away from gravity the space time is at rest with respect to the universe as a whole and contained in our sphere of the CMB? I am just guessing here. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: glennfish on 12/14/2015 09:22 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1456836#msg1456836">Quote from: SteveD on 12/13/2015 07:03 PM</a>
I might be able to spend some time over the holidays putting together the library section of the rfdriven website, if anyone is interested.
YES Please. Let me know what you need. I'll be in somewhat computer brain damaged mode from the 21st thru 3rd, so needs / demands prior please. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: glennfish on 12/14/2015 09:39 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457221#msg1457221">Quote from: ThereIWas3 on 12/14/2015 06:24 PM</a>
All we need is string-theorists getting involved. :)
Well I'll be a Calibi-Yau...
You know, falling off the cusps of manifolds was one of my favorite pass-times in grad school.
Whilst I'm in no position to propose a theory, you got my brain thinking about cascading bifurcations and wondering if any of the current accepted EM physics could be accurately described in a cusp catastrophe equivalent form... IF so, then there would be some interesting instabilities.
Challenge for those less impaired than I: Convert Maxwell's Equations to an ADS manifold, then identify boundary conditions and look for cases where they no longer result in the same solution. I see one master's thesis that almost got there...
http://researchcommons.waikato.ac.nz/bitstream/handle/10289/6526/thesis.pdf?sequence=3&isAllowed=y -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rq3 on 12/14/2015 09:40 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457012#msg1457012">Quote from: zen-in on 12/14/2015 04:12 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457008#msg1457008">Quote from: rfmwguy on 12/14/2015 03:53 AM</a>
...pretend there is a gif here
Got my extra class in 1981 but inactive since the 90s. Trouble is, a connector will make frustum at rf ground potential with a single center conductor. To isolate frustum from signal source, you'll need a triax connector or a dual center conductor if you want rf ground isolation.
Watch out for these and make sure they can handle the power and freq. Also, the triax will need a metal case on the outside of the frustum to minimize rf leakage.
Since the body of the magnetron is live with RF any balanced drive would need a balun (to drive the fustrum with a dipole). It would have to be pretty beefy and maybe fed coaxially from the magnetron. This intuitively seem wrong because you really want the fustrum to be at ground potential instead of floating. The magnetron already has a very good 1/4 λ drive (or maybe smaller) sticking out of the business end. The problem is one of matching the impedance of the magnetron drive with the fustrum, no matter what drive is used -balanced or unbalanced. But I think the balanced drive is a lot of trouble and would not work. It should be possible to calculate the impedance of the magnetron drive then design an inline matching network that would match the cavity impedance when 1/4 λ driven. Similar idea as calculating stripline impedances. For example reducing the diameter of the feed increases the impedance. The dielectric surrounding the center conductor would also be a factor. There of course has to be a very good gap-free shield around the center conductor and connecting the magnetron body with the Copper shell of the fustrum.
zen-in, I suspect you're right on. A kitchen magnetron is very grossly "matched" via primitive wavequide transitions from the magnetron antenna (very roughly 10 ohms) to free space (roughly 370 ohms) in the cooking chamber. The mismatch provided by the introduction of a load (food) is reponsible for "tuning" the entire assembly towards a best power match. The match can only be an approximation at best. Modern magnetrons can tolerate an infinite VSWR, with all of the emitted radio frequency (RF) being reflected back into the tube, but this is only due to modern materials and manufacturing techniques, and they can't do it indefinitely.
Those attempting to tune frustums should also note that extreme Q is only attainable with the very lightest possible coupling between the energy source and the filter. In the case of a quartz oscillator, the quartz crystal is driven at a level just barely above the level necessary to sustain oscillation. It may take them many seconds to start and settle on frequency. In the case of a dielectic resonant oscillator (DRO), probably more comparable to an EM drive frustum, the input and output coupling loops are extremely high impedance antennas designed to load the resonant cavity as little as possible. It is the resonant cavity that provides the high Q filter function, and the dielectric puck that provides low Q energy storage to sustain oscillation.
The EMdrive tries to achieve both high power level while maintaining high Q. The two are not necessarily mutually exclusive, but doing it with a splattering and noisy source like a magnetron may be problematic.
As an analogy, imagine striking a tuning fork near a guitar. IF the tuning fork AND one of the guitar strings are at the same frequency, the fork will drive the string into resonance. If you add an audio amplifier and speaker between the tuning fork and the guitar, you could probably destroy both the fork and the guitar. Think Ella Fitzgerald breaking a wine glass with a pure note.
Now try the same thing with a white noise source instead of a tuning fork. You'd have to create many watts of white noise before the guitar string would respond. A magnetron is pretty darn close to a radio frequency (RF) white noise source. Not as good as a noise diode, but pretty damn close. Think Ella Fitzgerald trying to break the wine glass by hissing at it. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: VAXHeadroom on 12/14/2015 10:03 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457302#msg1457302">Quote from: dustinthewind on 12/14/2015 09:01 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457275#msg1457275">Quote from: Rodal on 12/14/2015 08:10 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457250#msg1457250">Quote from: dustinthewind on 12/14/2015 07:09 PM</a>
...I found particularly interesting one mode posted by Shell before that had what appeared to be a traveling mode. It had dual input wave-guides and a mode that appeared at the bottom and then traveled up. I was wondering if a mode such as that might be difficult to generate with an antenna. I am not sure if it was but I suspected an asymmetry. What would be desired is an asymmetry of force on the cavity. Warptech pointed out to me in a video https://www.youtube.com/watch?v=ZqC3AVcuFaE that David states if they used a dielectric between the elements that it wouldn't get propulsion unless it was water. If water would be pushed in the opposite direction as propulsion via the electro-magnetic fields and water has a dielectric constant then I believe space also has a permittivity. One could then possibly think of space as being the water and it is being pushed in the opposite direction as propulsion. If space as a dielectric was indeed being pushed one would have to ask if it could be pushed through the cavity walls. I also question if a stable mode is what is really desired to be generated. Maybe that is why some success has been achieved with magnetrons. I think one can think of a gradient in the dielectric constant of free space as an effect of gravity leading to gravitational lensing. A gap between two plates with the casimir force, where radiation is lacking, may also possibly be thought of as differences in the dielectric constant of space between and outside the plates which would correspond to energy density.
Some ideas that come to mind are the Dynamical Casimir Effect: https://goo.gl/A5jUd6
Something interesting I found on the effect of gravity on the dielectric constant of space and gravity slowing down light and or dragging space: https://goo.gl/oZxyvB P.S. I don't think we can detect locally this change in the speed of light because distance contracts with light slowing down so effectively it dosn't change speed locally, only non-locally). One of the reasons why I am not sure LIGO will be able to detect gravity waves but maybe I don't know enough about it.
Here is a paper I found on (asymmetric, anti-symmetric, symmetric modes) generated by light on cavities: https://goo.gl/tTf0Ap
I'll attach an image of one of my hope in generating such an asymmetry. The idea behind it is normally the electric and magnetic force oppose each other in a phased array antenna but with counter-winding of the phased array antennas the interaction of the magnetic field can be reversed so that the effect of charge separation works with the magnetic effects. The only problem being how to achieve such currents in wires at microwave wavelengths. Maybe why Transverse electric effects are so successful in the frustum is because (if it works) it avoids charge separation in the frustum so that the magnetic effects don't work against the electric charge separation in the cavity walls.
If we can say the cavity is some how pushing on space time then maybe we can avoid the whole CoM issue.
OK, but then the proponents need to address the objections based on frame-indifference (is there a privileged frame? which frame? and why?) and conservation of energy, previously discussed by Frobnicat and DeltaMass.
I am not sure it would work but one might consider the preferred frame at the edge of an event horzion as moving at the speed of light and as such light can't escape. That is if gravity actually drags space time for some reason. Problem is that suggests light going into the black hole could non-locally exceed the speed of light. I would think rather light should slow down near the event horizon till it comes to a stand-still. Maybe this makes sense if the non-local space is moving at the speed of light into the event horizon and that the light in that space, as a result, is time dilated and there fore, stands still. Maybe then away from gravity the space time is at rest with respect to the universe as a whole and contained in our sphere of the CMB? I am just guessing here.
I saw that video when it was first shared. Fascinating concept. What strikes me here is that electricity in copper travels at just about exactly 0.5c (~6ns/ft). In a frustum with the antennas in the back, any electric field that gets induced into the copper will essentially be out of phase at the small end since the waves in the cavity travel at c. Won't this create an opposing magnetic field on the small end while generating an in-phase magnetic field on the big end? I'm sure that's WAY too simple a description - (my defense is I'm a software engineer, not a physicist ;) )
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rfmwguy on 12/14/2015 10:12 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457264#msg1457264">Quote from: SeeShells on 12/14/2015 07:49 PM</a>
I agree shell...that's the best way to look at it...unfortunately for me, I've ready only a few papers recently and they took me down several rabbit-holes. One of them today was a quantum vacuum photon paper here:<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457257#msg1457257">Quote from: rfmwguy on 12/14/2015 07:20 PM</a>(...)
This is no theory but just looking at things that stand out from some simple questions and facts we know.
p.s. There "ain't no way" I'm going to speculate on what it is...not yet. We either believe it works or we don't...or better yet...keep our minds open.
I'm moving operations into the area I've set aside in my home. I'll post more later.
http://arxiv.org/abs/1511.07849
Seems to be a credible theory for nanometer-scale reference frames, but practical at macro-scale? I doubt it. Face it Shell, there just isn't anything that jumps out at you and me...no "aha" type paper.
There are brain trusts here that are taking mental notes on our musings...something will break through soon, I hope.
Good luck on your home remodeling project! You've been busy, I know, but I'm going to send you some coal for your stocking if we don't see some pics soon ;) -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SeeShells on 12/14/2015 10:59 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457321#msg1457321">Quote from: rfmwguy on 12/14/2015 10:12 PM</a>
Oh my mess I just made??!!! Pictures??? I get some after I put the mess back together. We have several days of cold temps hitting and snow so I can work on getting it up to snuff.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457264#msg1457264">Quote from: SeeShells on 12/14/2015 07:49 PM</a>
I agree shell...that's the best way to look at it...unfortunately for me, I've ready only a few papers recently and they took me down several rabbit-holes. One of them today was a quantum vacuum photon paper here:<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457257#msg1457257">Quote from: rfmwguy on 12/14/2015 07:20 PM</a>(...)
This is no theory but just looking at things that stand out from some simple questions and facts we know.
p.s. There "ain't no way" I'm going to speculate on what it is...not yet. We either believe it works or we don't...or better yet...keep our minds open.
I'm moving operations into the area I've set aside in my home. I'll post more later.
http://arxiv.org/abs/1511.07849
Seems to be a credible theory for nanometer-scale reference frames, but practical at macro-scale? I doubt it. Face it Shell, there just isn't anything that jumps out at you and me...no "aha" type paper.
There are brain trusts here that are taking mental notes on our musings...something will break through soon, I hope.
Good luck on your home remodeling project! You've been busy, I know, but I'm going to send you some coal for your stocking if we don't see some pics soon ;)
I'm currently digging my way through a paper that is hitting hard and ringing many bells, but we'll see.
Shell
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Davinator on 12/14/2015 11:27 PM -
Stepping it to note that any uncivil posts will be removed. This thread is not above the site rules.
New people should check out the opening post, and perhaps use the entry level thread, because jumping into this thread because you read that joke of an article on Wired does not give you the right to jump into this ongoing update thread saying "There's no warp drive??? Fake!!"
Also, please do not "multiquote" to the post you have lots and lots of quotes in a response. It makes it all very hard to read the thread. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rfmwguy on 12/14/2015 11:59 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457358#msg1457358">Quote from: Davinator on 12/14/2015 11:27 PM</a>
Stepping it to note that any uncivil posts will be removed. This thread is not above the site rules.
Well, I was asleep at the switch on this one...just reviewed my notices (yeah I am not always online)...Thanks for stepping in. Understand the cleanup, thanks...whomever you are 8)
New people should check out the opening post, and perhaps use the entry level thread, because jumping into this thread because you read that joke of an article on Wired does not give you the right to jump into this ongoing update thread saying "There's no warp drive??? Fake!!"
Also, please do not "multiquote" to the post you have lots and lots of quotes in a response. It makes it all very hard to read the thread. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rfmwguy on 12/15/2015 12:13 AM -
Slight diversion here...I'd like to plug the L2 section and membership to this overall site. Even if you sign up for a couple of months as a trial, you'll get more info than you can handle...trust me...I can't even begin to scratch the surface.
Specifically, what I found is a very clean, almost precision level of no-nonsense posting regarding upcoming launches and ongoing missions. I was surprised to find NSF exclusive videos in there are well. Historic pics, etc.,
Think we all here on this thread need to support the overall site and L2 it for the latest and greatest. Who knows, perhaps someday emdrive might have their own L2 thread discussing insider info and mission status should the thing become scaleable and useable for space exploration.
In the meantime, we'll do our humble best here...but consider supporting NSF.
<Nope, I know what you're thinking - I made this post without any pressure from NSF, they don't play that way> :) -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: TheTraveller on 12/15/2015 01:08 AM -
Shell,
There is a reliable and lab proven way to excite TE01x mode in a resonant cavity without worrying about exciting other degenerative modes nor being concerned where to put the coupler nor it's effect on Q. Is coax Rf only. Excited loaded Q looks good.
This method uses 2 or 3 or 4 1/2 loop coupler placed in the centre of the end plate. I suggest for EmDrive use to use centre of the big end plate.
Have attached paper on the 2 and 3 loop couplers.
There are 2 more papers on this subject that are paywalled, which I did pay for and downloaded but can't' share. Will say the printed 4 loop/arc coupler is very clever.
http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=6616803&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Farnumber%3D6616803
http://search.proquest.com/openview/80573fccae41c61bba415fabc8554114/1?pq-origsite=gscholar&cbl=1936364
The attached image of the printed 4 arc coupler is public domain.
Maybe Aero can model this coupler in MEEP and share the results?
Will be testing this coupler as part of my EmDrive experimental program. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: dustinthewind on 12/15/2015 01:36 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457302#msg1457302">Quote from: dustinthewind on 12/14/2015 09:01 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457275#msg1457275">Quote from: Rodal on 12/14/2015 08:10 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457250#msg1457250">Quote from: dustinthewind on 12/14/2015 07:09 PM</a>
...
If we can say the cavity is some how pushing on space time then maybe we can avoid the whole CoM issue.
OK, but then the proponents need to address the objections based on frame-indifference (is there a privileged frame? which frame? and why?) and conservation of energy, previously discussed by Frobnicat and DeltaMass.
I am not sure it would work but one might consider the preferred frame at the edge of an event horzion as moving at the speed of light and as such light can't escape. That is if gravity actually drags space time for some reason. Problem is that suggests light going into the black hole could non-locally exceed the speed of light. I would think rather light should slow down near the event horizon till it comes to a stand-still. Maybe this makes sense if the non-local space is moving at the speed of light into the event horizon and that the light in that space, as a result, is time dilated and there fore, stands still. Maybe then away from gravity the space time is at rest with respect to the universe as a whole and contained in our sphere of the CMB? I am just guessing here.
Some possible support for the CMB as an absolute reference frame for space time. http://physics.stackexchange.com/questions/25928/is-the-cmb-rest-frame-special-where-does-it-come-from
I think this guy is also arguing the same. I can't suggest it is 100% accurate but it looks legit at first glance. https://scholar.google.com/scholar?cluster=11591112244843703577&hl=en&as_sdt=5,48&sciodt=0,48
If our space in a gravity well is flowing into the earth with respect to the space of the universe then as we rotate through our gravity well we may observe a slight shift in the dipole of the CMB as the earth rotates but I would have no idea if it would be something that would be observable or not with our weak gravity well compared to that of a large one.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457185#msg1457185">Quote from: SeeShells on 12/14/2015 05:17 PM</a>
One of my fav songs Dustinthewind... 8) I would agree with you but to see what is really happening you need to look at the frustum in X,Y and Z slices and tell me how many modes of operation do you see. https://drive.google.com/drive/folders/0B1XizxEfB23tbVYwc1Nsa29yZlk
Thanks, my dad used to sing that too me as a small one and it had similarity to my name. Some people think of the song as depressing and suggestive of our limited time but I like to think of it as us being the children of stars. Star children who are made of the dust of stars caught up in the solar winds of space and time. It gives it sort of an exotic feel.
I agree on the need to see more dimensions as I was wondering about the 3D nature. Thanks for the link. It looks complicated but it is apparent the simulation was run with a wave-guide included. I guess I would try and use a wave-guide as simulated to reproduce the modes. It almost looks like you might be able to excite it with an X shaped antenna through the bottom plate which is made of two T's. The current would be moving out on one T and current moving in on the other T but I can't say for sure. Possibly confirmed by SEZ_vu-ez.gif but the bottom plate (Bez_vu_ez.gif) looks a bit different.
I would guess there are others that know more about this than I would. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SeeShells on 12/15/2015 02:00 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457391#msg1457391">Quote from: dustinthewind on 12/15/2015 01:36 AM</a>
We don't know more trust me, you're very sharp and it's refreshing. It's always intrigues me, here we are star stuff, contemplating star stuff. That's heavy.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457302#msg1457302">Quote from: dustinthewind on 12/14/2015 09:01 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457275#msg1457275">Quote from: Rodal on 12/14/2015 08:10 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457250#msg1457250">Quote from: dustinthewind on 12/14/2015 07:09 PM</a>...
If we can say the cavity is some how pushing on space time then maybe we can avoid the whole CoM issue.
OK, but then the proponents need to address the objections based on frame-indifference (is there a privileged frame? which frame? and why?) and conservation of energy, previously discussed by Frobnicat and DeltaMass.
I am not sure it would work but one might consider the preferred frame at the edge of an event horzion as moving at the speed of light and as such light can't escape. That is if gravity actually drags space time for some reason. Problem is that suggests light going into the black hole could non-locally exceed the speed of light. I would think rather light should slow down near the event horizon till it comes to a stand-still. Maybe this makes sense if the non-local space is moving at the speed of light into the event horizon and that the light in that space, as a result, is time dilated and there fore, stands still. Maybe then away from gravity the space time is at rest with respect to the universe as a whole and contained in our sphere of the CMB? I am just guessing here.
Some possible support for the CMB as an absolute reference frame for space time. http://physics.stackexchange.com/questions/25928/is-the-cmb-rest-frame-special-where-does-it-come-from
I think this guy is also arguing the same. I can't suggest it is 100% accurate but it looks legit at first glance. https://scholar.google.com/scholar?cluster=11591112244843703577&hl=en&as_sdt=5,48&sciodt=0,48
If our space in a gravity well is flowing into the earth with respect to the space of the universe then as we rotate through our gravity well we may observe a slight shift in the dipole of the CMB as the earth rotates but I would have no idea if it would be something that would be observable or not with our weak gravity well compared to that of a large one.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457185#msg1457185">Quote from: SeeShells on 12/14/2015 05:17 PM</a>
One of my fav songs Dustinthewind... 8) I would agree with you but to see what is really happening you need to look at the frustum in X,Y and Z slices and tell me how many modes of operation do you see. https://drive.google.com/drive/folders/0B1XizxEfB23tbVYwc1Nsa29yZlk
Thanks, my dad used to sing that too me as a small one and it had similarity to my name. Some people think of the song as depressing and suggestive of our limited time but I like to think of it as us being the children of stars. Star children who are made of the dust of stars caught up in the solar winds of space and time. It gives it sort of an exotic feel.
I agree on the need to see more dimensions as I was wondering about the 3D nature. Thanks for the link. It looks complicated but it is apparent the simulation was run with a wave-guide included. I guess I would try and use a wave-guide as simulated to reproduce the modes. It almost looks like you might be able to excite it with an X shaped antenna through the bottom plate which is made of two T's. The current would be moving out on one T and current moving in on the other T but I can't say for sure. Possibly confirmed by SEZ_vu-ez.gif but the bottom plate (Bez_vu_ez.gif) looks a bit different.
I would guess there are others that know more about this than I would.
You are seeing my build with the dual opposing waveguides. The reason it differs from other builds that we have seen with waveguides is because off the top section I have a tuning chamber that allows me to run through multiple modes and even the effects they can have on one another as the tune progresses from one to the other. The waveguides will allow the multiplicity of modes through the tuning. I was pretty jazzed it gives me the ability to do that, antennas can't do that. Not sure what I'll find in generated thrust profiles and it progresses through tuning but it will be good data.
Shell -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: VAXHeadroom on 12/15/2015 02:03 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457391#msg1457391">Quote from: dustinthewind on 12/15/2015 01:36 AM</a>
...
I did a 3D animation of this data...
I agree on the need to see more dimensions as I was wondering about the 3D nature. Thanks for the link. It looks complicated but it is apparent the simulation was run with a wave-guide included. I guess I would try and use a wave-guide as simulated to reproduce the modes. It almost looks like you might be able to excite it with an X shaped antenna through the bottom plate which is made of two T's. The current would be moving out on one T and current moving in on the other T but I can't say for sure. Possibly confirmed by SEZ_vu-ez.gif but the bottom plate (Bez_vu_ez.gif) looks a bit different.
I would guess there are others that know more about this than I would.
https://www.youtube.com/watch?v=ScbsAdGHz3Q
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: RERT on 12/15/2015 10:40 AM -
Hi. Dr. Rodal at post 163: 'nothing in the cosmos...self-accelerating...'. You were discussing something completely different, but reminded me of this thought.
Shells almost said it at post 169, but Galaxies are accelerating away from each other now. If I understand right, Dark Energy is the name of the invisible and undetected thing we invented to balance the books to preserve our conservation laws in the face of this observation.
This may rank as a blindingly obvious remark, but if the EMDrive effect turns out to be real there will be a scramble to identify the balancing item, and CoM and CoE will remain intact, just slightly modified. This has happened before in other contexts, and most likely will happen again.
Cheers,
R. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/15/2015 11:55 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457654#msg1457654">Quote from: RERT on 12/15/2015 10:40 AM</a>
Hi. Dr. Rodal at post 163: 'nothing in the cosmos...self-accelerating...'. You were discussing something completely different, but reminded me of this thought.
Yes, in the end the big difference is that the evidence for acceleration of the expansion of the Universe is well accepted by scientists as evidenced by observations of supernovae, reconciliation of the measured geometry of space with the total amount of matter in the universe (cosmic microwave background) , analysis of large-scale structure, and of observational Hubble constant data. All of this has been published in excellent peer-reviewed journals and professionally analyzed.
Shells almost said it at post 169, but Galaxies are accelerating away from each other now. If I understand right, Dark Energy is the name of the invisible and undetected thing we invented to balance the books to preserve our conservation laws in the face of this observation.
This may rank as a blindingly obvious remark, but if the EMDrive effect turns out to be real there will be a scramble to identify the balancing item, and CoM and CoE will remain intact, just slightly modified. This has happened before in other contexts, and most likely will happen again.
Cheers,
R.
On the other hand, evidence for self-acceleration of the EM Drive is very weak and objectionable: thermal effects have insufficiently been accounted for in most EM Drive experiments. Thermal effects have not been analyzed in the published reports: no one has conducted Computational Fluid Dynamics analysis to analyze natural thermal convection, no one has published thermal expansion analysis and measurements. Only two experimenters (and very recently) have performed tests in vacuum: NASA and Tajmar. Yang and Shawyer have failed to conduct a single experiment in vacuum. Shawyer has stated words to the effect that unless there is some vibration or nudging, experiments give zero forces. NASA has not yet published their experiments in peer-reviewed journals and NASA has not yet published their experiments in vacuum in any form (we only know of them through these NSF thread communications). NASA's experimental force measurements in vacuum (communicated to these threads) are orders of magnitude smaller than what was claimed by Shawyer and Yang: they could be the result of forces created by thermal expansion, due to microwave induction heating. Tajmar's experimental measurements in vacuum at TU Dresden are even smaller and Tajmar concludes "our test campaign can not confirm or refute in any way the claims of the EMDrive".
So, the bottom line is that the test campaigns conducted so far have failed to demonstrate the claims of anomalous EM Drive forces (they have failed to demonstrate that they cannot be explained by classical conventional effects that render it of no use for space travel) . To make things worse, the initial claims for anomalous EM Drive forces (Shawyer's "theory") were based on serious misunderstandings (conflation of open waveguides with closed cavities, ignoring the balancing radiation pressure on the side walls of the EM Drive, etc.), and there is no compelling theory showing why a closed, geometrically asymmetric cavity excited by microwave radiation should result in self-acceleration useful for spaceflight. (Prof. Woodward thinks that if the NASA experiments show an anomalous force, that it must be due to NASA's use of a dielectric insert and Woodward's Mach Effect. Dr. White rejects Shawyer's and Yang's "theories" and instead proposes a Quantum Vacuum theory that has met opposition from others based on the immutability of the quantum vacuum.)
There were some very interesting (experimental and theoretical) discussions with Paul March (NASA) in previous threads but those exchanges, unfortunately, have stopped some time ago. Fifteen years after formation of SPR Ltd., scientific confirmation of anomalous forces from the EM Drive remains unfulfilled. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rfmwguy on 12/15/2015 12:41 PM -
Computational Fluid Dynamics analysis to analyze natural thermal convection, no one has published thermal expansion analysis and measurements that can be reviewed. - doc
Ok doc, nice points but we need more specifics...what software is needed for these tests and can you help us calculate a vertical lift component for balance beam measurements?
We've already determined lorentz is minimal in horizontal measurements in ambient atmosphere, would you agree that these two elements would be the last pieces of the puzzle?
Shell and I would need your help with the fluid dynamics and thermal expansion calcs...sound like fun? -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/15/2015 12:54 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457688#msg1457688">Quote from: rfmwguy on 12/15/2015 12:41 PM</a>
Computational Fluid Dynamics analysis to analyze natural thermal convection, no one has published thermal expansion analysis and measurements that can be reviewed. - doc
Ok doc, nice points but we need more specifics...what software is needed for these tests and can you help us calculate a vertical lift component for balance beam measurements?
We've already determined lorentz is minimal in horizontal measurements in ambient atmosphere, would you agree that these two elements would be the last pieces of the puzzle?
Shell and I would need your help with the fluid dynamics and thermal expansion calcs...sound like fun?
There are several software packages for computational fluid dynamics that I specifically discussed: for example ANSYS CFX and ANSYS FLUENT CFD. The hardware computational resources and professional expertise for such analysis make the Meep analysis discussed here pale in comparison. The Navier Stokes equations are nonlinear while Maxwell's equations are linear.
Closed-form solution of the Navier Stokes equations is out of the question (except for some very simplistic cases not applicable to these experiments). Just making progress towards a mathematical theory that will give insight into these equations is so difficult that it constitutes an (unachieved) Millenium Prize Problem, with a 1 million dollar prize ! (https://en.wikipedia.org/wiki/Millennium_Prize_Problems).
As previously discussed the most effective way to deal with thermal convection effects is either by testing in vacuum (as done by Tajmar and NASA) or by testing EM Drive forces large enough that they clearly stand above any thermal effects (as proposed by the Canadian team). Several people in these threads have proposed interesting ideas to at least quantify and minimize thermal convection effects, that have not yet been addressed (identical magnetron heated EM Drives at both ends of a balanced beam, with only one exciting the interior of the cavity, etc.)
Testing in a vacuum (or performing computational fluid mechanics analysis) only addresses the thermal convection effects, it does not address thermal expansion effects due to microwave induction heating.
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: ThereIWas3 on 12/15/2015 12:56 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457314#msg1457314">Quote from: rq3 on 12/14/2015 09:40 PM</a>
A magnetron is pretty darn close to a radio frequency (RF) white noise source. Not as good as a noise diode, but pretty damn close. Think Ella Fitzgerald trying to break the wine glass by hissing at it.
Especially a "free running" magnetron with no frequency-control feedback. Nobody uses vacuum-tube osciallators any more for good reason. All modern radio transmitters use synthesizers locked to a temperature-controlled reference crystal. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rfmwguy on 12/15/2015 01:10 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457691#msg1457691">Quote from: Rodal on 12/15/2015 12:54 PM</a>
Yikes...not for diyers...ok let's boil this down abit.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457688#msg1457688">Quote from: rfmwguy on 12/15/2015 12:41 PM</a>(...)Computational Fluid Dynamics analysis to analyze natural thermal convection, no one has published thermal expansion analysis and measurements that can be reviewed. - doc(...)
There are several software packages for computational fluid dynamics that I specifically discussed: for example ANSYS CFX and ANSYS FLUENT CFD. The hardware computational resources and professional expertise for such analysis make the Meep analysis discussed here pale in comparison. The Navier Stokes equation are nonlinear while Maxwell's equations are linear.
As previously discussed the most effective way to deal with thermal convection effects is either by testing in vacuum (as done by Tajmar and NASA) or by testing EM Drive forces large enough that they clearly stand above any thermal effects (as proposed by the Canadian team). Several people in these threads have proposed interesting ideas to at least quantify and minimize thermal convection effects, that have not yet been addressed (EM Drives at both ends of a balanced beam, only one exciting the cavity, etc.)
Testing in a vacuum (or performing computational fluid mechanics analysis) only addresses the thermal convection effects, it does not address thermal expansion effects due to microwave induction heating.
Would you agree that the Li's paper positing lorentz force describing a torsional (rotary) force of up to a few micronewtons is irrelevant for horizontal beam measurements?
If so, would you agree that experimenters using horizontal beams without a vacuum only have fluid dynamics or thermal expansion analysis to overcome? -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: OnlyMe on 12/15/2015 01:42 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457654#msg1457654">Quote from: RERT on 12/15/2015 10:40 AM</a>
Hi. Dr. Rodal at post 163: 'nothing in the cosmos...self-accelerating...'. You were discussing something completely different, but reminded me of this thought.
Shells almost said it at post 169, but Galaxies are accelerating away from each other now. If I understand right, Dark Energy is the name of the invisible and undetected thing we invented to balance the books to preserve our conservation laws in the face of this observation.
This may rank as a blindingly obvious remark, but if the EMDrive effect turns out to be real there will be a scramble to identify the balancing item, and CoM and CoE will remain intact, just slightly modified. This has happened before in other contexts, and most likely will happen again.
Cheers,
R.
Dark energy as an unknown variable, is not to preserve conservation laws, it is an adjustment intended to preserve the validity of general relativity at the scales of the observed acceleration.
The terms dark energy and dark matter have become so common, the reason they are called dark is not always clear. They are names assigned to unknown variables, whose purpose is to compensate for the fact that without them, our best model of gravitation general relativity, fails to accurately describe what we observe...
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/15/2015 01:49 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457701#msg1457701">Quote from: rfmwguy on 12/15/2015 01:10 PM</a>
I am not familiar with a paper from Li on Lorentz forces for torsional pendulums. I recall that Frobnicat discussed electromagnetic forces on NASA's torsional pendulum in very early threads, and we discussed the effects of the magnetic damper early on (in thread #2 or earlier), including several discussions with Paul March (NASA) in earlier threads.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457691#msg1457691">Quote from: Rodal on 12/15/2015 12:54 PM</a>
Yikes...not for diyers...ok let's boil this down abit.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457688#msg1457688">Quote from: rfmwguy on 12/15/2015 12:41 PM</a>(...)Computational Fluid Dynamics analysis to analyze natural thermal convection, no one has published thermal expansion analysis and measurements that can be reviewed. - doc(...)
There are several software packages for computational fluid dynamics that I specifically discussed: for example ANSYS CFX and ANSYS FLUENT CFD. The hardware computational resources and professional expertise for such analysis make the Meep analysis discussed here pale in comparison. The Navier Stokes equation are nonlinear while Maxwell's equations are linear.
As previously discussed the most effective way to deal with thermal convection effects is either by testing in vacuum (as done by Tajmar and NASA) or by testing EM Drive forces large enough that they clearly stand above any thermal effects (as proposed by the Canadian team). Several people in these threads have proposed interesting ideas to at least quantify and minimize thermal convection effects, that have not yet been addressed (EM Drives at both ends of a balanced beam, only one exciting the cavity, etc.)
Testing in a vacuum (or performing computational fluid mechanics analysis) only addresses the thermal convection effects, it does not address thermal expansion effects due to microwave induction heating.
Would you agree that the Li's paper positing lorentz force describing a torsional (rotary) force of up to a few micronewtons is irrelevant for horizontal beam measurements?
If so, would you agree that experimenters using horizontal beams without a vacuum only have fluid dynamics or thermal expansion analysis to overcome? -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rfmwguy on 12/15/2015 01:55 PM - Worth a read...mr li is a poster here but forgot nick: http://arxiv.org/abs/1510.07752
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Tellmeagain on 12/15/2015 01:55 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457701#msg1457701">Quote from: rfmwguy on 12/15/2015 01:10 PM</a>
Would you agree that the Li's paper positing lorentz force describing a torsional (rotary) force of up to a few micronewtons is irrelevant for horizontal beam measurements?
rfmwgy, I appreciate your doing your own experiment. I read NFS occasionally, and happen to see your question when I am having a sick leave today. Actually our paper (the Li's paper) had shown Lorentz force up to 41 micro-Newtons (see fig 4 of the paper), and that was with the NASA style second generation damper. If we use NASA's first generation damper, that number can be easily doubled or even tripled. Yes, I believe all NASA saw in their 2014 paper were Lorentz force. The ball is now in NASA's court. They need to address this issue in their next paper. Are there ways to eliminate/control for Lorentz force in an experiment? Yes, there are, but they missed that in their 2014 paper. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/15/2015 02:06 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457718#msg1457718">Quote from: rfmwguy on 12/15/2015 01:55 PM</a>
Worth a read...mr li is a poster here but forgot nick: http://arxiv.org/abs/1510.07752
Was that (Li) the paper that motivated a short-lived return by Paul March (NASA) to these threads? If that is the case, did Paul March address the paper vis-a-vis the NASA experiments in his short-lived return to these NASA threads?
(I was not active in these threads at the time of those exchanges.) -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rfmwguy on 12/15/2015 02:07 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457719#msg1457719">Quote from: Tellmeagain on 12/15/2015 01:55 PM</a>
There you are! Sorry mr li, bad memory. For us horizontal balance beam types, were wondering if you measured any non- torsional or y axis lorentz forces? - dave<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457701#msg1457701">Quote from: rfmwguy on 12/15/2015 01:10 PM</a>
Would you agree that the Li's paper positing lorentz force describing a torsional (rotary) force of up to a few micronewtons is irrelevant for horizontal beam measurements?
rfmwgy, I appreciate your doing your own experiment. I read NFS occasionally, and happen to see your question when I am having a sick leave today. Actually our paper (the Li's paper) had shown Lorentz force up to 41 micro-Newtons (see fig 4 of the paper), and that was with the NASA style second generation damper. If we use NASA's first generation damper, that number can be easily doubled or even tripled. Yes, I believe all NASA saw in their 2014 paper were Lorentz force. The ball is now in NASA's court. They need to address this issue in their next paper. Are there ways to eliminate/control for Lorentz force in an experiment? Yes, there are, but they missed that in their 2014 paper. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rfmwguy on 12/15/2015 02:09 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457723#msg1457723">Quote from: Rodal on 12/15/2015 02:06 PM</a>
Yes, and mr li would be best to comment on pauls response...it was a very interesting topic.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457718#msg1457718">Quote from: rfmwguy on 12/15/2015 01:55 PM</a>Worth a read...mr li is a poster here but forgot nick: http://arxiv.org/abs/1510.07752
Was that (Li) the paper that motivated a short-lived return by Paul March (NASA) to these threads? If that is the case, did Paul March address the paper vis-a-vis the NASA experiments in his short-lived return to these NASA threads?
(I was not active in these threads at the time of those exchanges.) -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rfmwguy on 12/15/2015 02:19 PM -
Doc, here is pauls reply from T5:
http://forum.nasaspaceflight.com/index.php?topic=38577.msg1440938#msg1440938
Seems they've moved to a balance beam -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Tellmeagain on 12/15/2015 02:21 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457724#msg1457724">Quote from: rfmwguy on 12/15/2015 02:07 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457719#msg1457719">Quote from: Tellmeagain on 12/15/2015 01:55 PM</a>
There you are! Sorry mr li, bad memory. For us horizontal balance beam types, were wondering if you measured any non- torsional or y axis lorentz forces? - dave<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457701#msg1457701">Quote from: rfmwguy on 12/15/2015 01:10 PM</a>
Would you agree that the Li's paper positing lorentz force describing a torsional (rotary) force of up to a few micronewtons is irrelevant for horizontal beam measurements?
rfmwgy, I appreciate your doing your own experiment. I read NFS occasionally, and happen to see your question when I am having a sick leave today. Actually our paper (the Li's paper) had shown Lorentz force up to 41 micro-Newtons (see fig 4 of the paper), and that was with the NASA style second generation damper. If we use NASA's first generation damper, that number can be easily doubled or even tripled. Yes, I believe all NASA saw in their 2014 paper were Lorentz force. The ball is now in NASA's court. They need to address this issue in their next paper. Are there ways to eliminate/control for Lorentz force in an experiment? Yes, there are, but they missed that in their 2014 paper.
We didn't measure the Lorentz force on the y axis (meaning vertical?). This is because the current loops in our experiment were vertical, so the Lorentz forces we saw would be confined in the horizontal direction. Remember that The Lorentz force is perpendicular both to the magnet field and to the current.
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/15/2015 02:30 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457733#msg1457733">Quote from: rfmwguy on 12/15/2015 02:19 PM</a>
Doc, here is pauls reply from T5:
Oh, I see. Has Li answered and addressed the following statement by Paul March ? (Bold added for emphasis)
http://forum.nasaspaceflight.com/index.php?topic=38577.msg1440938#msg1440938
Seems they've moved to a balance beamQuote from: Star-DriveI will tell you that we first built and installed a 2nd generation, closed face magnetic damper that reduced the stray magnetic fields in the vacuum chamber by at least an order of magnitude and any Lorentz force interactions it could produce. I also changed up the torque pendulum's grounding wire scheme and single point ground location to minimize ground loop current interactions with the remaining stray magnetic fields and unbalanced dc currents from the RF amplifier when its turned on. This reduced the Lorentz force interaction to less than 2 micro-Newton (uN) for the dummy load test.
that seems to be in conflict (again I was not active in the thread at that time, so I am not clearly following this) with this latest statement (are Li and Paul March referring to the same "2nd generation" damper when Li states "that was with the NASA style second generation damper" ?):<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457719#msg1457719">Quote from: Tellmeagain on 12/15/2015 01:55 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457701#msg1457701">Quote from: rfmwguy on 12/15/2015 01:10 PM</a>
Would you agree that the Li's paper positing lorentz force describing a torsional (rotary) force of up to a few micronewtons is irrelevant for horizontal beam measurements?
rfmwgy, I appreciate your doing your own experiment. I read NFS occasionally, and happen to see your question when I am having a sick leave today. Actually our paper (the Li's paper) had shown Lorentz force up to 41 micro-Newtons (see fig 4 of the paper), and that was with the NASA style second generation damper. If we use NASA's first generation damper, that number can be easily doubled or even tripled. Yes, I believe all NASA saw in their 2014 paper were Lorentz force. The ball is now in NASA's court. They need to address this issue in their next paper. Are there ways to eliminate/control for Lorentz force in an experiment? Yes, there are, but they missed that in their 2014 paper.
(Bold added for emphasis) -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Tellmeagain on 12/15/2015 02:35 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457733#msg1457733">Quote from: rfmwguy on 12/15/2015 02:19 PM</a>
Doc, here is pauls reply from T5:
http://forum.nasaspaceflight.com/index.php?topic=38577.msg1440938#msg1440938
Seems they've moved to a balance beam
They have been using balance beam (torsion balance) since day one. Instead of a hanging string, they used the hinge-like torsion bearing. An google image search pointed back to Dr. Rodal's NFS post, http://forum.nasaspaceflight.com/index.php?topic=29276.msg1286631#msg1286631 -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/15/2015 02:38 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457740#msg1457740">Quote from: Tellmeagain on 12/15/2015 02:35 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457733#msg1457733">Quote from: rfmwguy on 12/15/2015 02:19 PM</a>
Doc, here is pauls reply from T5:
http://forum.nasaspaceflight.com/index.php?topic=38577.msg1440938#msg1440938
Seems they've moved to a balance beam
They have been using balance beam (torsion balance) since day one. Instead of a hanging string, they used the hinge-like torsion bearing. An google image search pointed back to Dr. Rodal's NFS post, http://forum.nasaspaceflight.com/index.php?topic=29276.msg1286631#msg1286631
In some posts Paul March discussed "additional", independent tests with a magnetron exciting another EM Drive cavity to be conducted (in addition to the torsional pendulum tests) in a separate NASA "teeter-totter" arrangement. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Tellmeagain on 12/15/2015 02:43 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457739#msg1457739">Quote from: Rodal on 12/15/2015 02:30 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457733#msg1457733">Quote from: rfmwguy on 12/15/2015 02:19 PM</a>
Doc, here is pauls reply from T5:
Oh, I see. Has Li answered and addressed the following statement by Paul March ? (Bold added for emphasis)
http://forum.nasaspaceflight.com/index.php?topic=38577.msg1440938#msg1440938
Seems they've moved to a balance beamQuote from: Star-DriveI will tell you that we first built and installed a 2nd generation, closed face magnetic damper that reduced the stray magnetic fields in the vacuum chamber by at least an order of magnitude and any Lorentz force interactions it could produce. I also changed up the torque pendulum's grounding wire scheme and single point ground location to minimize ground loop current interactions with the remaining stray magnetic fields and unbalanced dc currents from the RF amplifier when its turned on. This reduced the Lorentz force interaction to less than 2 micro-Newton (uN) for the dummy load test.
that seems to contradict this latest statement (are Li and Paul March referring to the same "2nd generation" damper when Li states "that was with the NASA style second generation damper" ?):<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457719#msg1457719">Quote from: Tellmeagain on 12/15/2015 01:55 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457701#msg1457701">Quote from: rfmwguy on 12/15/2015 01:10 PM</a>
Would you agree that the Li's paper positing lorentz force describing a torsional (rotary) force of up to a few micronewtons is irrelevant for horizontal beam measurements?
rfmwgy, I appreciate your doing your own experiment. I read NFS occasionally, and happen to see your question when I am having a sick leave today. Actually our paper (the Li's paper) had shown Lorentz force up to 41 micro-Newtons (see fig 4 of the paper), and that was with the NASA style second generation damper. If we use NASA's first generation damper, that number can be easily doubled or even tripled. Yes, I believe all NASA saw in their 2014 paper were Lorentz force. The ball is now in NASA's court. They need to address this issue in their next paper. Are there ways to eliminate/control for Lorentz force in an experiment? Yes, there are, but they missed that in their 2014 paper.
(Bold added for emphasis)
I didn't comment on Paul's statement. Yes we mimicked their second generation damper, but it was not emphasized enough in the paper. It is shown in fig 1 of our paper, where the damper is enclosed. We also have photos in supplemental materials, which is available with request. I attach them here so you can see that we used the closed face magnet damper. As it always happens, nothing is perfect in engineering, so there is still leaked magnetic field, as we have shown in the first two attached photos. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Tellmeagain on 12/15/2015 02:48 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457744#msg1457744">Quote from: Tellmeagain on 12/15/2015 02:43 PM</a>
I didn't comment on Paul's statement. Yes we mimicked their second generation damper, but it was not emphasized enough in the paper. It is shown in fig 1 of our paper, where the damper is enclosed. We also have photos in supplemental materials, which is available with request. I attach them here so you can see that we used the closed face magnet damper. As it always happens, nothing is perfect in engineering, so there is still leaked magnetic field, as we have shown in the first two attached photos.
It was not very different from NASA's second generation damper, seen at
http://nextbigfuture.com/2014/09/paul-march-is-providing-more.html -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/15/2015 03:04 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457746#msg1457746">Quote from: Tellmeagain on 12/15/2015 02:48 PM</a>
In early threads, I advocated the use of a simple oil damper (as used in classical physics experiments to measure gravitational forces a long time ago) instead of any magnetic damper.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457744#msg1457744">Quote from: Tellmeagain on 12/15/2015 02:43 PM</a>I didn't comment on Paul's statement. Yes we mimicked their second generation damper, but it was not emphasized enough in the paper. It is shown in fig 1 of our paper, where the damper is enclosed. We also have photos in supplemental materials, which is available with request. I attach them here so you can see that we used the closed face magnet damper. As it always happens, nothing is perfect in engineering, so there is still leaked magnetic field, as we have shown in the first two attached photos.
It was not very different from NASA's second generation damper, seen at
http://nextbigfuture.com/2014/09/paul-march-is-providing-more.html
Brito Marini and Galian (and later on Marini and Galian) nullified the claims of propellant-less thrust from a Mach-Lorentz Woodward effect thruster using a simple pendulum with the thruster all self-contained and using oil damping:
http://arc.aiaa.org/doi/abs/10.2514/6.2009-5070
http://arc.aiaa.org/doi/abs/10.2514/1.46541?journalCode=jpp
https://www.researchgate.net/profile/Ricardo_Marini -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Tellmeagain on 12/15/2015 03:18 PM -
I now comment on Paul's other statements. He said:
"I also changed up the torque pendulum's grounding wire scheme and single point ground location to minimize ground loop current interactions with the remaining stray magnetic fields and unbalanced dc currents from the RF amplifier when its turned on. This reduced the Lorentz force interaction to less than 2 micro-Newton (uN) for the dummy load test."
I need to see their next paper to comment on their new grounding scheme. However, the 2 uN dummy load test could not imply a successful grounding scheme. Remember that their dummy load was not grounded to the beam (see our paper for this point). If their frustum was grounded to the beam, then the dummy load test and frustum test were with different DC distribution. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Tellmeagain on 12/15/2015 03:26 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457749#msg1457749">Quote from: Rodal on 12/15/2015 03:04 PM</a>
In early threads, I advocated the use of a simple oil damper (as used in classical physics experiments to measure gravitational forces a long time ago) instead of any magnetic damper.
Brito Marini and Galian (and later on Marini and Galian) nullified the claims of propellant-less thrust from a Mach-Lorentz Woodward effect thruster using a simple pendulum with the thruster all self-contained and using oil damping:
http://arc.aiaa.org/doi/abs/10.2514/6.2009-5070
http://arc.aiaa.org/doi/abs/10.2514/1.46541?journalCode=jpp
https://www.researchgate.net/profile/Ricardo_Marini
Good points. NASA should try the oil damper, as Tajmar did. They should also rotate their test bed and measure thrusts with different directions relative to the earth magnetic field. A better grounding scheme ,such as the star grounding scheme see-shell mentioned, will help. With that, the grounding of the frustum should be only through the shield of the RF cable. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rfmwguy on 12/15/2015 03:31 PM -
Now, this is just weird...a vna sweep of an unmodified baritone bell...36dB return loss(!) centering about 2.14 GHz. Simple copper board clamped on end, no other modifications, mag antenna probe I've been usin for NSF-1701 sweeps.
Will try closing off narrow end and see where it tunes up in frequency. Can I tune it to 2.45 GHz? Maybe...
1st tune (steel wool in bore - don't be a hater) resulted in 2.74 GHz resonance and 20dB RL. Yep, I can tune it. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/15/2015 04:15 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457766#msg1457766">Quote from: rfmwguy on 12/15/2015 03:31 PM</a>
Now, this is just weird...a vna sweep of an unmodified baritone bell...36dB return loss(!) centering about 2.14 GHz. Simple copper board clamped on end, no other modifications, mag antenna probe I've been usin for NSF-1701 sweeps.
Will try closing off narrow end and see where it tunes up in frequency. Can I tune it to 2.45 GHz? Maybe...
1st tune (steel wool in bore - don't be a hater) resulted in 2.74 GHz resonance and 20dB RL. Yep, I can tune it.
This is a Do-It-Yourself-at-home experimental confirmation by RFMWGUY of what I have been stating for a long time in these threads: that Shawyer's claim that there is a cut-off frequency for electromagnetic cavity resonance is incorrect (as was already known from undergraduate textbooks).
It is easy to show that the small throat end of the tested wind instrument has a dimension smaller than corresponding to the so-called cut-off frequency.
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: OnlyMe on 12/15/2015 04:32 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457823#msg1457823">Quote from: Rodal on 12/15/2015 04:15 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457766#msg1457766">Quote from: rfmwguy on 12/15/2015 03:31 PM</a>
Now, this is just weird...a vna sweep of an unmodified baritone bell...36dB return loss(!) centering about 2.14 GHz. Simple copper board clamped on end, no other modifications, mag antenna probe I've been usin for NSF-1701 sweeps.
Will try closing off narrow end and see where it tunes up in frequency. Can I tune it to 2.45 GHz? Maybe...
1st tune (steel wool in bore - don't be a hater) resulted in 2.74 GHz resonance and 20dB RL. Yep, I can tune it.
This is a Do-It-Yourself-at-home experimental confirmation by RFMWGUY of what I have been stating for a long time in these threads: that Shawyer's claim that there is a cut-off frequency for electromagnetic cavity resonance is incorrect (as was already known from undergraduate textbooks).
It is easy to show that the small throat end of the tested wind instrument has a dimension much smaller than corresponding to the so-called cut-off frequency.
I believe the only way this is applicable to Shawyer's cutoff statement is if you begin with the assumption that there is no thrust. His statement seems tied to a cutoff frequency associated with generating thrust.
Separately...
Something that might be interesting is if rfmwguy were to rerun the initial test (without the steel wool) and instead of closing the mouth piece end with a plate, terminate it into a faraday cage with ground isolated from the baritone. Maybe even try to set up some means of determining if any microwaves in the range produced by the magnetron even escape through the mouth piece end. The diameter and geometry of the instrument may wind up grounding out all microwaves before they reach a open mouth piece. This would experimentally confirm the last comment above. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: CraigPichach on 12/15/2015 04:36 PM -
An update on our 100kW test project. Model using HFSS using eigenmode solver, TE013 mode 914.85MHz Q=133526. Loop coupled design for ease of build, cost and stress concerns.
As we are planning to use a high power coax line and are designing as a pressure vessel, one recommendation is to use copper cladded stainless steel... does anyone see any objections to the use of this material so long as we clad the internals with copper? This would help us with vessel integrity and cooling; while I do think we will achieve resonance is there any EM-Drive Q thruster theories that say not to do this (i.e. impacting the quantum vacuum??).
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/15/2015 04:37 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457864#msg1457864">Quote from: OnlyMe on 12/15/2015 04:32 PM</a>
There is no statement in Shaywer's papers (that I have seen) stating that his cut-off equations are only applicable to anomalous thrust effects. Shawyer makes the statements about cut-off frequency without any such "thrust dependence" justification in his papers. Actually, Shawyer conflates open waveguides and resonating cavities in his papers and presents his equations (including quoting Prof. Cullen's Ph.D. thesis out of context for a resonating cavity) without such modifiers in his papers.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457823#msg1457823">Quote from: Rodal on 12/15/2015 04:15 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457766#msg1457766">Quote from: rfmwguy on 12/15/2015 03:31 PM</a>Now, this is just weird...a vna sweep of an unmodified baritone bell...36dB return loss(!) centering about 2.14 GHz. Simple copper board clamped on end, no other modifications, mag antenna probe I've been usin for NSF-1701 sweeps.
Will try closing off narrow end and see where it tunes up in frequency. Can I tune it to 2.45 GHz? Maybe...
1st tune (steel wool in bore - don't be a hater) resulted in 2.74 GHz resonance and 20dB RL. Yep, I can tune it.
This is a Do-It-Yourself-at-home experimental confirmation by RFMWGUY of what I have been stating for a long time in these threads: that Shawyer's claim that there is a cut-off frequency for electromagnetic cavity resonance is incorrect (as was already known from undergraduate textbooks).
It is easy to show that the small throat end of the tested wind instrument has a dimension much smaller than corresponding to the so-called cut-off frequency.
I believe the only way this is applicable to Shawyer's cutoff statement is if you begin with the assumption that there is no thrust. His statement seems tied to a cutoff frequency associated with generating thrust.
Separately...
Something that might be interesting is if rfmwguy were to rerun the initial test (without the steel wool) and instead of closing the mouth piece end with a plate, terminate it into a faraday cage with ground isolated from the baritone. Maybe even try to set up some means of determining if any microwaves in the range produced by the magnetron even escape through the mouth piece end. The diameter and geometry of the instrument may wind up grounding out all microwaves before they reach a open mouth piece. This would experimentally confirm the last comment above.
If anyone is to interpret Shawyer's equations (including his strange special relativity modifications) as only applicable to thrust, such "thrust dependent" constraint on special relativity and "thrust dependent" constraint on resonance should be proven (or at least discussed) by Shawyer, rather than assumed ab ibnitio by the reader of his papers.
There is no explanation as to why resonance above cut-off would result in anomalous thrust while resonance below cut-off would result in no thrust. Shawyer does not even state that his cut-off equations are only applicable to anomalous thrust effects.
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/15/2015 04:39 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457874#msg1457874">Quote from: CraigPichach on 12/15/2015 04:36 PM</a>
An update on our 100kW test project. Model using HFSS using eigenmode solver, TE013 mode 914.85MHz Q=133526. Loop coupled design for ease of build, cost and stress concerns.
As we are planning to use a high power coax line and are designing as a pressure vessel, one recommendation is to use copper cladded stainless steel... does anyone see any objections to the use of this material so long as we clad the internals with copper? This would help us with vessel integrity and cooling; while I do think we will achieve resonance is there any EM-Drive Q thruster theories that say not to do this (i.e. impacting the quantum vacuum??).
It is noteworthy to remark that this is the ONLY test by anyone (as far as I know) where there is a deliberate attempt to test for anomalous thrust forces that are way beyond the forces produced by thermal effects. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Tellmeagain on 12/15/2015 04:49 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457877#msg1457877">Quote from: Rodal on 12/15/2015 04:39 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457874#msg1457874">Quote from: CraigPichach on 12/15/2015 04:36 PM</a>
An update on our 100kW test project. Model using HFSS using eigenmode solver, TE013 mode 914.85MHz Q=133526. Loop coupled design for ease of build, cost and stress concerns.
As we are planning to use a high power coax line and are designing as a pressure vessel, one recommendation is to use copper cladded stainless steel... does anyone see any objections to the use of this material so long as we clad the internals with copper? This would help us with vessel integrity and cooling; while I do think we will achieve resonance is there any EM-Drive Q thruster theories that say not to do this (i.e. impacting the quantum vacuum??).
It is noteworthy to remark that this is the ONLY test by anyone (as far as I know) where there is a deliberate attempt to test for anomalous thrust forces that are way beyond the forces produced by thermal effects.
Assuming the frustum is resonating with 100KW input, won't we see 100KW of heat generated by the furstum? If we see 100W heat only, we can only assume that 99.9% power are reflected back and this test is no better than a 100W test. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: zen-in on 12/15/2015 04:49 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457864#msg1457864">Quote from: OnlyMe on 12/15/2015 04:32 PM</a>
...
I believe the only way this is applicable to Shawyer's cutoff statement is if you begin with the assumption that there is no thrust. His statement seems tied to a cutoff frequency associated with generating thrust.
Separately...
Something that might be interesting is if rfmwguy were to rerun the initial test (without the steel wool) and instead of closing the mouth piece end with a plate, terminate it into a faraday cage with ground isolated from the baritone. Maybe even try to set up some means of determining if any microwaves in the range produced by the magnetron even escape through the mouth piece end. The diameter and geometry of the instrument may wind up grounding out all microwaves before they reach a open mouth piece. This would experimentally confirm the last comment above.
The valves are missing so there is not an unbroken path from the bell to the mouthpiece fitting. He could try detecting RF in the valve tubes. Earlier I thought that was an E♭ tuba. I stand corrected it is a baritone. A BB♭ tuba would have an appropriate sized bell for these experiments and sometimes they are Silver plated. My personal opinion however, as a former BB♭ tuba player, is it would be a sin to destroy such a melodious instrument. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rfmwguy on 12/15/2015 05:12 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457891#msg1457891">Quote from: zen-in on 12/15/2015 04:49 PM</a>
This one is in bad shape zen...I was going to desolder but its already well beyond repair. I will saw the bell at its longest, straightest length and get rid of the silly steel wool. I was able to plug the bore and get tuning from abt 2.1 to 2.7 GHz. A simple plate to close it off is the next step.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457864#msg1457864">Quote from: OnlyMe on 12/15/2015 04:32 PM</a>
...
I believe the only way this is applicable to Shawyer's cutoff statement is if you begin with the assumption that there is no thrust. His statement seems tied to a cutoff frequency associated with generating thrust.
Separately...
Something that might be interesting is if rfmwguy were to rerun the initial test (without the steel wool) and instead of closing the mouth piece end with a plate, terminate it into a faraday cage with ground isolated from the baritone. Maybe even try to set up some means of determining if any microwaves in the range produced by the magnetron even escape through the mouth piece end. The diameter and geometry of the instrument may wind up grounding out all microwaves before they reach a open mouth piece. This would experimentally confirm the last comment above.
The valves are missing so there is not an unbroken path from the bell to the mouthpiece fitting. He could try detecting RF in the valve tubes. Earlier I thought that was an E♭ tuba. I stand corrected it is a baritone. A BB♭ tuba would have an appropriate sized bell for these experiments and sometimes they are Silver plated. My personal opinion however, as a former BB♭ tuba player, is it would be a sin to destroy such a melodious instrument.
I did trombone, so we're in the same mindset about not destroying perfectly good instruments. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: OnlyMe on 12/15/2015 05:15 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457875#msg1457875">Quote from: Rodal on 12/15/2015 04:37 PM</a>
There is no statement in Shaywer's papers (that I have seen) stating that his cut-off equations are only applicable to anomalous thrust effects. Shawyer makes the statements about cut-off frequency without any such "thrust dependence" justification in his papers. Actually, Shawyer conflates open waveguides and resonating cavities in his papers and presents his equations (including quoting Prof. Cullen's Ph.D. thesis out of context for a resonating cavity) without such modifiers in his papers.
If anyone is to interpret Shawyer's equations (including his strange special relativity modifications) as only applicable to thrust, such "thrust dependent" constraint on special relativity and "thrust dependent" constraint on resonance should be proven (or at least discussed) by Shawyer, rather than assumed ab ibnitio by the reader of his papers.
There is no disagreement that Shawyer does not seem to me to have ever provided sufficient detail to support his claims... And his theory paper was enough for me to dismiss his EMDrive, long before I was ever aware of these discussions.
Personally I am not yet convinced there is any thrust that will not be explainable or that this will lead to a functional drive system component.., but I am hopeful that My skepticism is misplaced and that some truly significant New Physics may be discovered in the experimental process, currently underway.
So, I am skeptical... Still the very basis of Shawyer's claims, establishes a baseline from which any of his statements should be evaluated, whether he makes the claims explicitly or not. Since he is claiming that thrust is developed, any statement declaring that a cutoff frequency is important, has to be associated with the fundamental claim. The connection is implied. Even if I agree that the information he has shared publicly, is shoddy, at best. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/15/2015 05:26 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457909#msg1457909">Quote from: OnlyMe on 12/15/2015 05:15 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457875#msg1457875">Quote from: Rodal on 12/15/2015 04:37 PM</a>
There is no statement in Shaywer's papers (that I have seen) stating that his cut-off equations are only applicable to anomalous thrust effects. Shawyer makes the statements about cut-off frequency without any such "thrust dependence" justification in his papers. Actually, Shawyer conflates open waveguides and resonating cavities in his papers and presents his equations (including quoting Prof. Cullen's Ph.D. thesis out of context for a resonating cavity) without such modifiers in his papers.
If anyone is to interpret Shawyer's equations (including his strange special relativity modifications) as only applicable to thrust, such "thrust dependent" constraint on special relativity and "thrust dependent" constraint on resonance should be proven (or at least discussed) by Shawyer, rather than assumed ab ibnitio by the reader of his papers.
There is no disagreement that Shawyer does not seem to me to have ever provided sufficient detail to support his claims... And his theory paper was enough for me to dismiss his EMDrive, long before I was ever aware of these discussions.
Personally I am not yet convinced there is any thrust that will not be explainable or that this will lead to a functional drive system component.., but I am hopeful that My skepticism is misplaced and that some truly significant New Physics may be discovered in the experimental process, currently underway.
So, I am skeptical... Still the very basis of Shawyer's claims, establishes a baseline from which any of his statements should be evaluated, whether he makes the claims explicitly or not. Since he is claiming that thrust is developed, any statement declaring that a cutoff frequency is important, has to be associated with the fundamental claim. The connection is implied. Even if I agree that the information he has shared publicly, is shoddy, at best.
OK.
To me it sounds like Shawyer is engaged in a contradiction in his papers, whenever he invokes equations for open waveguides (for example: 1) equations for cut-off, 2) quoting, out of context, equations from Prof. Cullen's PhD thesis or 3) quoting radiation pressure equations that are only applicable to waveguides with one end open and the other end closed).
I don't see any way out of Shawyer's contradiction unless someone would be able to explain in what sense is a closed cavity like an open waveguide that is open at one end.
NASA has attempted to differentiate the ends by asymmetric placement of a dielectric inside the EM Drive and has reported in its 2014 report that no thrust force measurements were measurable without the dielectric.
Notsosureofit has addressed the possible asymmetry from a different perspective than Shawyer (Notsosureofit present an interesting mode dependence that is not discussed by Shawyer).
Aquino made a valiant theoretical effort in this regard: differentiating both ends of the EM Drive, suggesting the use of a ferromagnetic end at one of the ends of the EM Drive.
Why is it that no institutional tester, or DIY tester has yet attempted to conduct measurements with one EM Drive end made of a ferromagnetic coating to test Aquino's conjecture ?
Isn't it simple enough to just replace one of the diamagnetic (copper) ends with a ferromagnetic end (or a ferromagnetic coated end, to save weight) and measure the force (to compare both cases) ??? -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/15/2015 05:40 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457891#msg1457891">Quote from: zen-in on 12/15/2015 04:49 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457864#msg1457864">Quote from: OnlyMe on 12/15/2015 04:32 PM</a>
...
I believe the only way this is applicable to Shawyer's cutoff statement is if you begin with the assumption that there is no thrust. His statement seems tied to a cutoff frequency associated with generating thrust.
Separately...
Something that might be interesting is if rfmwguy were to rerun the initial test (without the steel wool) and instead of closing the mouth piece end with a plate, terminate it into a faraday cage with ground isolated from the baritone. Maybe even try to set up some means of determining if any microwaves in the range produced by the magnetron even escape through the mouth piece end. The diameter and geometry of the instrument may wind up grounding out all microwaves before they reach a open mouth piece. This would experimentally confirm the last comment above.
The valves are missing so there is not an unbroken path from the bell to the mouthpiece fitting. He could try detecting RF in the valve tubes. Earlier I thought that was an E♭ tuba. I stand corrected it is a baritone. A BB♭ tuba would have an appropriate sized bell for these experiments and sometimes they are Silver plated. My personal opinion however, as a former BB♭ tuba player, is it would be a sin to destroy such a melodious instrument.
and Merry Christmas to you all:
https://www.youtube.com/watch?v=uy26H7oMGZg
(E flat tuba from approximately 1900, purchased on ebay for $20 )
Gustav Holst's "Cranham", also known as the Christmas carol "In the Bleak Midwinter"
(I love Holst's "The Planets" Op. 32 :) )
https://www.youtube.com/watch?v=nkOFol_V-rM -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SeeShells on 12/15/2015 06:25 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457749#msg1457749">Quote from: Rodal on 12/15/2015 03:04 PM</a>
I went one step futher in the dampening and instead of oil which can change it's viscosity over temperature I went with a antifreeze glycerol mix in the water which doesn't.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457746#msg1457746">Quote from: Tellmeagain on 12/15/2015 02:48 PM</a>
In early threads, I advocated the use of a simple oil damper (as used in classical physics experiments to measure gravitational forces a long time ago) instead of any magnetic damper.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457744#msg1457744">Quote from: Tellmeagain on 12/15/2015 02:43 PM</a>I didn't comment on Paul's statement. Yes we mimicked their second generation damper, but it was not emphasized enough in the paper. It is shown in fig 1 of our paper, where the damper is enclosed. We also have photos in supplemental materials, which is available with request. I attach them here so you can see that we used the closed face magnet damper. As it always happens, nothing is perfect in engineering, so there is still leaked magnetic field, as we have shown in the first two attached photos.
It was not very different from NASA's second generation damper, seen at
http://nextbigfuture.com/2014/09/paul-march-is-providing-more.html
Brito Marini and Galian (and later on Marini and Galian) nullified the claims of propellant-less thrust from a Mach-Lorentz Woodward effect thruster using a simple pendulum with the thruster all self-contained and using oil damping:
http://arc.aiaa.org/doi/abs/10.2514/6.2009-5070
http://arc.aiaa.org/doi/abs/10.2514/1.46541?journalCode=jpp
https://www.researchgate.net/profile/Ricardo_Marini
back to work...
Shell -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: OnlyMe on 12/15/2015 06:38 PM -
"I went with a antifreeze glycerol mix in the water which doesn't."
At 20 degrees in the shop, probably a good idea! -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SeeShells on 12/15/2015 06:52 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457960#msg1457960">Quote from: OnlyMe on 12/15/2015 06:38 PM</a>
"I went with a antifreeze glycerol mix in the water which doesn't."
Was a win win.
At 20 degrees in the shop, probably a good idea!
I'm moving virtually the entire shop minus the Faraday cage into the house. I can't get the dang thing through the double doors and it weighs a bunch. I'll be building another not as big.
Anyway back to work. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/15/2015 07:47 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457911#msg1457911">Quote from: Rodal on 12/15/2015 05:26 PM</a>
...
X_Ray was kind enough to remember another example
OK.
To me it sounds like Shawyer is engaged in a contradiction in his papers, whenever he invokes equations for open waveguides (for example: 1) equations for cut-off, 2) quoting, out of context, equations from Prof. Cullen's PhD thesis or 3) quoting radiation pressure equations that are only applicable to waveguides with one end open and the other end closed).
I don't see any way out of Shawyer's contradiction unless someone would be able to explain in what sense is a closed cavity like an open waveguide that is open at one end.
NASA has attempted to differentiate the ends by asymmetric placement of a dielectric inside the EM Drive and has reported in its 2014 report that no thrust force measurements were measurable without the dielectric.
Notsosureofit has addressed the possible asymmetry from a different perspective than Shawyer (Notsosureofit present an interesting mode dependence that is not discussed by Shawyer).
Aquino made a valiant theoretical effort in this regard: differentiating both ends of the EM Drive, suggesting the use of a ferromagnetic end at one of the ends of the EM Drive.
Why is it that no institutional tester, or DIY tester has yet attempted to conduct measurements with one EM Drive end made of a ferromagnetic coating to test Aquino's conjecture ?
Isn't it simple enough to just replace one of the diamagnetic (copper) ends with a ferromagnetic end (or a ferromagnetic coated end, to save weight) and measure the force (to compare both cases) ???Quote from: X_RayIt can be shown that there are reflections at the open end of a waveguide back into the direction of the source because of the different i.e. discontinuity of the impedance between waveguide and free space. Of course this reflection is very small. ::) A horn antenna makes this transition into free space much smoother...
Yes, the reflection (and transmission) at that boundary is indeed a function of the impedance, and of the angle at which the incident wave hits that boundary (and of the loss factors, if tan delta is not zero).
One can also show (I think this was first done by Einstein) the reflection for a moving boundary, which introduces Doppler shifts in the frequencies of the reflected and transmitted waves. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rfmwguy on 12/15/2015 10:08 PM -
Spent a good chunk of the day playing around with baritone bell tuning. Its natural resonance is 2.14 ghz. I can tune to 2.7 ghz but return loss (match) suffers greatly.
Here's what I've determined...a seamless brass frustum without much exponential taper would be ideal. RL is above 30db is achievable This is significantly better than my copper mesh. Q and Qr are impressive. Soooo...I'm about ready to contact musical instrument makers...locally...and see if they might whip something up for me in non-laquered brass using my original dimensions plus factoring in the tuning bands...will be slightly exponential and I'll give them the dimensions.
Seems like a good way to go for next year...NSF-1701 was a great homebrew project...time to take it to the next level...NSF-1701A in honor of all the peeps here that have supported and encouraged me: Doc, michelle, phil, glenn, deltamass, paul, chris b., roy, don and so many more.
Onwards and upwards... -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SeeShells on 12/15/2015 10:37 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458085#msg1458085">Quote from: rfmwguy on 12/15/2015 10:08 PM</a>
Spent a good chunk of the day playing around with baritone bell tuning. Its natural resonance is 2.14 ghz. I can tune to 2.7 ghz but return loss (match) suffers greatly.
Here is a tip, looked once at gutter people to do your copper.
Here's what I've determined...a seamless brass frustum without much exponential taper would be ideal. RL is above 30db is achievable This is significantly better than my copper mesh. Q and Qr are impressive. Soooo...I'm about ready to contact musical instrument makers...locally...and see if they might whip something up for me in non-laquered brass using my original dimensions plus factoring in the tuning bands...will be slightly exponential and I'll give them the dimensions.
Seems like a good way to go for next year...NSF-1701 was a great homebrew project...time to take it to the next level...NSF-1701A in honor of all the peeps here that have supported and encouraged me: Doc, michelle, phil, glenn, deltamass, paul, chris b., roy, don and so many more.
Onwards and upwards...
http://www.rutlandguttersupply.com/finials/Finial_Cones.asp -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: RFPlumber on 12/15/2015 11:02 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457712#msg1457712">Quote from: OnlyMe on 12/15/2015 01:42 PM</a>
The terms dark energy and dark matter have become so common, the reason they are called dark is not always clear...
I thought the reason they call dark matter 'dark' is because it does not interact in any way with electro-magnetic spectrum (which is what gives us a sense of 'light' :) ). Basically, for certain gravitational lens effects the gravitational force required is a lot more than can be accounted for by all the matter visible in the region. Hence the theory that there must also be some non-visible, aka dark, matter which produces gravity but does not interact with EM.
Yes, the same dark matter concept also helps explain certain observed anomalies with rotation of galaxies, etc. but for those anomalies there at least exist a few alternative theories. IMHO, the gravitational lens is the most compelling case for dark matter. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: OnlyMe on 12/15/2015 11:27 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458103#msg1458103">Quote from: RFPlumber on 12/15/2015 11:02 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457712#msg1457712">Quote from: OnlyMe on 12/15/2015 01:42 PM</a>
The terms dark energy and dark matter have become so common, the reason they are called dark is not always clear...
I thought the reason they call dark matter 'dark' is because it does not interact in any way with electro-magnetic spectrum (which is what gives us a sense of 'light' :) ). Basically, for certain gravitational lens effects the gravitational force required is a lot more than can be accounted for by all the matter visible in the region. Hence the theory that there must also be some non-visible, aka dark, matter which produces gravity but does not interact with EM.
Yes, the same dark matter concept also helps explain certain observed anomalies with rotation of galaxies, etc. but for those anomalies there at least exist a few alternative theories. IMHO, the gravitational lens is the most compelling case for dark matter.
They are unknown variables, which cannot be directly observed. What they are depends entirely on assumptions, that GR as we currently understand it, applies universally and some unobservable form of matter and energy exists, required such that GR remains valid in all cases.
Don't get me wrong I am not saying either does not exist. Just that they must remain placeholders until proven.
We (or others on this thread) can actually build frustums with the intent to prove or disprove thrust. Any tests we can conduct to determine the nature or even the existence of dark matter and dark energy will remain dependent on unprovable assumptions. At least for the present.
but my original point or intent was just to correct the misunderstanding that either originated to resolve conservation issues. Though in some respects the accelerating expansion of space, rather than an accelerating recession velocity of things in space, could be thought of as an attempt to preserve the speed of light as a universal speed limit. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: masonke on 12/16/2015 12:09 AM -
As of 12/15/2015, 8:00 PM/EST.
Is there any (NEW) news on the EM DRIVE testing? -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: MazonDel on 12/16/2015 12:09 AM - Heh, my favorite passtime at work while walking through the catwalks of the megawatt+ radar we are building is to try and imagine how I might convert the test chamber into a rather sizable frustum....Would I be fired? Yes. Might the building launch itself halfway across the state? Probably not, but if it did....so worth it. >:D
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: aero on 12/16/2015 12:19 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458110#msg1458110">Quote from: OnlyMe on 12/15/2015 11:27 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458103#msg1458103">Quote from: RFPlumber on 12/15/2015 11:02 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457712#msg1457712">Quote from: OnlyMe on 12/15/2015 01:42 PM</a>
The terms dark energy and dark matter have become so common, the reason they are called dark is not always clear...
I thought the reason they call dark matter 'dark' is because it does not interact in any way with electro-magnetic spectrum (which is what gives us a sense of 'light' :) ). Basically, for certain gravitational lens effects the gravitational force required is a lot more than can be accounted for by all the matter visible in the region. Hence the theory that there must also be some non-visible, aka dark, matter which produces gravity but does not interact with EM.
Yes, the same dark matter concept also helps explain certain observed anomalies with rotation of galaxies, etc. but for those anomalies there at least exist a few alternative theories. IMHO, the gravitational lens is the most compelling case for dark matter.
They are unknown variables, which cannot be directly observed. What they are depends entirely on assumptions, that GR as we currently understand it, applies universally and some unobservable form of matter and energy exists, required such that GR remains valid in all cases.
Don't get me wrong I am not saying either does not exist. Just that they must remain placeholders until proven.
We (or others on this thread) can actually build frustums with the intent to prove or disprove thrust. Any tests we can conduct to determine the nature or even the existence of dark matter and dark energy will remain dependent on unprovable assumptions. At least for the present.
but my original point or intent was just to correct the misunderstanding that either originated to resolve conservation issues. Though in some respects the accelerating expansion of space, rather than an accelerating recession velocity of things in space, could be thought of as an attempt to preserve the speed of light as a universal speed limit.
Something that might interest you all.
http://phys.org/news/2015-12-results-world-sensitive-dark-detector.html (http://phys.org/news/2015-12-results-world-sensitive-dark-detector.html)
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SeeShells on 12/16/2015 12:36 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457874#msg1457874">Quote from: CraigPichach on 12/15/2015 04:36 PM</a>
An update on our 100kW test project. Model using HFSS using eigenmode solver, TE013 mode 914.85MHz Q=133526. Loop coupled design for ease of build, cost and stress concerns.
Wow, I wondered what happened to you guys. I'm so waiting for your results and with a TE013 mode. Do you have any images from your HFSS run?
As we are planning to use a high power coax line and are designing as a pressure vessel, one recommendation is to use copper cladded stainless steel... does anyone see any objections to the use of this material so long as we clad the internals with copper? This would help us with vessel integrity and cooling; while I do think we will achieve resonance is there any EM-Drive Q thruster theories that say not to do this (i.e. impacting the quantum vacuum??).
Big Thumbs up for you guys!!!
Shell -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: dustinthewind on 12/16/2015 01:05 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457391#msg1457391">Quote from: dustinthewind on 12/15/2015 01:36 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457302#msg1457302">Quote from: dustinthewind on 12/14/2015 09:01 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457275#msg1457275">Quote from: Rodal on 12/14/2015 08:10 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457250#msg1457250">Quote from: dustinthewind on 12/14/2015 07:09 PM</a>
...
If we can say the cavity is some how pushing on space time then maybe we can avoid the whole CoM issue.
OK, but then the proponents need to address the objections based on frame-indifference (is there a privileged frame? which frame? and why?) and conservation of energy, previously discussed by Frobnicat and DeltaMass.
I am not sure it would work but one might consider the preferred frame at the edge of an event horzion as moving at the speed of light and as such light can't escape. That is if gravity actually drags space time for some reason. Problem is that suggests light going into the black hole could non-locally exceed the speed of light. I would think rather light should slow down near the event horizon till it comes to a stand-still. Maybe this makes sense if the non-local space is moving at the speed of light into the event horizon and that the light in that space, as a result, is time dilated and there fore, stands still. Maybe then away from gravity the space time is at rest with respect to the universe as a whole and contained in our sphere of the CMB? I am just guessing here.
Some possible support for the CMB as an absolute reference frame for space time. http://physics.stackexchange.com/questions/25928/is-the-cmb-rest-frame-special-where-does-it-come-from
I think this guy is also arguing the same. I can't suggest it is 100% accurate but it looks legit at first glance. https://scholar.google.com/scholar?cluster=11591112244843703577&hl=en&as_sdt=5,48&sciodt=0,48
If our space in a gravity well is flowing into the earth with respect to the space of the universe then as we rotate through our gravity well we may observe a slight shift in the dipole of the CMB as the earth rotates but I would have no idea if it would be something that would be observable or not with our weak gravity well compared to that of a large one.
...
I think these guys are barking up the same tree as I. It may also relate to, I think his name is, "White's" paper about quantum virtual particles being pushed out the back of the frustum, maybe.
"DOES THE QUANTUM VACUUM FALL NEAR THE EARTH?"
by: Tom Ostoma and Mike Trushyk
1999
https://goo.gl/pmDepK
no citations unfortunately but lots of material. also hosted at cern. More can be found on this I believe by searching "EMQG" theory or "electro-magnetic quantum gravity". I am not finding much on it though. More found on normal google than scholar.google.com . Maybe it was integrated or superseded by quantum gravity in general. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rogo on 12/16/2015 08:33 AM -
Could the following note maybe explain why the EMDrive could work?
Professor of Physics, A. P. French, has a relevant note in his very informative book, Special
Relativity (1968), p. 242-243; 267 "Relativity and electricity":
"Now the electric field due to a stationary source charge is radial and, of course, spherically
symmetrical; that is, it is the same in all directions. It is simply the Coulomb field . . . . If the
source charge is moving uniformly, the electric field is no longer spherically symmetrical. Its
strength is different in different directions. But, at each instant, the direction of the electric field
is still radial with respect to the position of the source charge at that same instant.
If you think about this last result a bit—that at each instant the electric field due to a uniformly
moving source charge is directed radially away from the position of the source charge at that
same instant—you may begin to realize that this is a very surprising result."
I found this paper very tought provoking and tackling all sorts of problems with curreny theories out of the box.
http://scripturalphysics.org/4v4a/BeyondEinstein.pdf (http://scripturalphysics.org/4v4a/BeyondEinstein.pdf) -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: oliverio on 12/16/2015 08:53 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458211#msg1458211">Quote from: Rogo on 12/16/2015 08:33 AM</a>
Could the following note maybe explain why the EMDrive could work?
Professor of Physics, A. P. French, has a relevant note in his very informative book, Special
Relativity (1968), p. 242-243; 267 "Relativity and electricity":
"Now the electric field due to a stationary source charge is radial and, of course, spherically
symmetrical; that is, it is the same in all directions. It is simply the Coulomb field . . . . If the
source charge is moving uniformly, the electric field is no longer spherically symmetrical. Its
strength is different in different directions. But, at each instant, the direction of the electric field
is still radial with respect to the position of the source charge at that same instant.
If you think about this last result a bit—that at each instant the electric field due to a uniformly
moving source charge is directed radially away from the position of the source charge at that
same instant—you may begin to realize that this is a very surprising result."
I think this just speaks to the unity of source and field. There is a temptation to believe that when you push on the source of a charge, the source of the charge is "dragging" in some respect its electric field along with it.
On the contrary; when you push on the source of a field, you are moving the field itself as well as the matter that generates it (there is no particularly useful distinction in this thought experiment). -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: OnlyMe on 12/16/2015 01:07 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458211#msg1458211">Quote from: Rogo on 12/16/2015 08:33 AM</a>
Could the following note maybe explain why the EMDrive could work?
Professor of Physics, A. P. French, has a relevant note in his very informative book, Special
Relativity (1968), p. 242-243; 267 "Relativity and electricity":
"Now the electric field due to a stationary source charge is radial and, of course, spherically
symmetrical; that is, it is the same in all directions. It is simply the Coulomb field . . . . If the
source charge is moving uniformly, the electric field is no longer spherically symmetrical. Its
strength is different in different directions. But, at each instant, the direction of the electric field
is still radial with respect to the position of the source charge at that same instant.
If you think about this last result a bit—that at each instant the electric field due to a uniformly
moving source charge is directed radially away from the position of the source charge at that
same instant—you may begin to realize that this is a very surprising result."
I found this paper very tought provoking and tackling all sorts of problems with curreny theories out of the box.
http://scripturalphysics.org/4v4a/BeyondEinstein.pdf (http://scripturalphysics.org/4v4a/BeyondEinstein.pdf)
This really isn't something new. An analog is often discussed with respect to the gravitational field of a uniformly moving object. Something that is important to remember is that almost always these are essentially vacuum solution hypotheticals. Meaning they only involve how the field and its source are affected by either a uniform or in some cases accelerating motion. Nothing else exists in these hypotheticals other than the charge and its electric field in this case.., and the important thing to remember, when thinking of the effect relative to a resonating frustum, or any object is, that the field electric or gravitational propagates at the speed of light, while any realistic uniform motion will be classical. Only when the uniform mortion becomes relativistic or should the motion involve some significant acceleration and distances, would there be any detectable asymmetry in the field, relative to its source.
In the case of gravitational fields, there has been a lot of work to develope models that account for how the acceleration of an object affects the field, because we have many objects in the solar system which are accelerating relative to our preferred frame, the earth.... And yet the results remain for the most part insignificant, since even the accelerations are small compared to the propagation speed of the field.
In a way some of the attempts to detect gravitational waves are based on this same principle, the affect of accelerations on the way a gravitational field propagates... Think binary massive objects, rapidly orbiting one anther. Their velocities relative to our detection devices are significant and changing, which should result in detectable changes in the propagation of the field... Changes we have yet to confirm, but based on the same fundamental concepts presented in your post. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: dustinthewind on 12/16/2015 01:32 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458211#msg1458211">Quote from: Rogo on 12/16/2015 08:33 AM</a>
Could the following note maybe explain why the EMDrive could work?
Professor of Physics, A. P. French, has a relevant note in his very informative book, Special
Relativity (1968), p. 242-243; 267 "Relativity and electricity":
"Now the electric field due to a stationary source charge is radial and, of course, spherically
symmetrical; that is, it is the same in all directions. It is simply the Coulomb field . . . . If the
source charge is moving uniformly, the electric field is no longer spherically symmetrical. Its
strength is different in different directions. But, at each instant, the direction of the electric field
is still radial with respect to the position of the source charge at that same instant.
If you think about this last result a bit—that at each instant the electric field due to a uniformly
moving source charge is directed radially away from the position of the source charge at that
same instant—you may begin to realize that this is a very surprising result."
I found this paper very tought provoking and tackling all sorts of problems with curreny theories out of the box.
http://scripturalphysics.org/4v4a/BeyondEinstein.pdf (http://scripturalphysics.org/4v4a/BeyondEinstein.pdf)
I think Edward Purcell in his book called it electric field pancaking which happens when observing the charge in a relative moving frame. He insisted that the electric flux was conserved as the charge field pancaked so as to conserve charge. I think electric field pancaking is why objects tend to flatten when moving at relativistic speed with respect to an observer. It's also why a velocity dependent dipole potential is represented by the magnetic field (charge bunches up on the side of the current loop with higher relative velocity with respect to a moving observer. It can be thought it is because the E-fields are flattened on one side of the current loop or that time is slowed down on one side. I think Maxwell's equations take pancaking into account. Edit: Curl E =-dB/dt, curl B = ... , divergence of B=0, divergence E = rho/epsilon_o take into account the relativistic behavior of the charge electric fields so that the charges can be modeled as simple spherical electric fields and then have the magnetic effects superimposed over it. It was likely easier than modeling relativistic electric fields.
There are some interesting effects where if you accelerate the charge in a solenoid, it pushes more flux out the open ends of the solenoid (via pancaking). Flux is pushed perpendicular to the direction of travel. If you have a low capacitance capacitor that is concentric around the solenoid (two large concentric sheets) and you accelerate the current the flux through the capacitor changes and holds giving a voltage. It is such a small amount of charge for a small capacitance that you can only observe it with a high resistance volt meter (across the two sheets) and not long before the current bleeds through but when you shut off the solenoid the voltage reverses so the pressure was there the whole time. Of course I was worried other effects might be contributing to that but I suspected that is what it was. I had to use Styrofoam to hold the capacitor sheets. If you use wood the charge will bleed off through the wood, to return the capacitor back to zero volts, because the wood is too low of a resistance. Even Styrofoam could only hold it for a bit. It took a high resistance volt-meter as well. I am not sure how exactly that effect fits into Maxwell's equations. A changing magnetic field should be like light (induce an impulse) but it wouldn't induce a constant pressure at constant current I would think. It was an interesting experiment.
@sghill xD ya I get it barking up the same tree and that tree is falling. Tree falls in the forest and no one is around does it make any sound. Especially dealing with what might be imaginary particles. clever. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: sghill on 12/16/2015 02:49 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458141#msg1458141">Quote from: dustinthewind on 12/16/2015 01:05 AM</a>
"DOES THE QUANTUM VACUUM FALL NEAR THE EARTH?"
by: Tom Ostoma and Mike Trushyk
1999
What if no one hears it? -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rfmwguy on 12/16/2015 05:12 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458368#msg1458368">Quote from: sghill on 12/16/2015 02:49 PM</a>
Physics/science discussions can be dry and tedious...we all need a little laugh every once in a while.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458141#msg1458141">Quote from: dustinthewind on 12/16/2015 01:05 AM</a>"DOES THE QUANTUM VACUUM FALL NEAR THE EARTH?"
by: Tom Ostoma and Mike Trushyk
1999
What if no one hears it? -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/16/2015 06:05 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458125#msg1458125">Quote from: masonke on 12/16/2015 12:09 AM</a>
As of 12/15/2015, 8:00 PM/EST.
The last institutional published experimental report was by Tajmar at the Technische Universität Dresden in Germany.
Is there any (NEW) news on the EM DRIVE testing?
We are waiting to hear news from NASA regarding:
1) Publication of NASA's Eagleworks EM Drive tests performed in vacuum, including discussion/analysis of thermal expansion effects and effects from forces resulting from the magnetic damper.
2) Confirmation of whether or not a new testing campaign will commence at NASA Glenn to replicate the tests at NASA Johnson (Eagleworks), and if so when are the NASA Glenn results expected to be announced/reported.
Remarkably, Yang (in China) has not published any new results for a considerable amount of time, and her last publication dealt with the considerable thermal effects on her experiments (her paper on temperature vs. time measurements throughout a heated EM Drive using embedded thermocouples).
Concerning Do-It-Yourself experiments, the last experimental report was by RFMWGUY. We are waiting to hear from Shell on her meticulously and thoroughly designed testing program. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: sghill on 12/16/2015 07:45 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458478#msg1458478">Quote from: Rodal on 12/16/2015 06:05 PM</a>
Confirmation of whether or not a new testing campaign will commence at NASA Glenn to replicate the tests at NASA Johnson (Eagleworks), and if so when are the NASA Glenn results expected to be announced/reported.
Remarkably, Yang (in China) has not published any new results for a considerable amount of time, and her last publication dealt with the considerable thermal effects on her experiments (her paper on temperature vs. time measurements throughout a heated EM Drive using embedded thermocouples).
Any announcement that EW is going to Glenn would be wildly major news IMHO because it has to mean that they've seen thrust levels above the noise floor that the Glenn equipment requires before testing there, and also the thrust isn't already attributable to anomalous thrust.
The lack of publishing from Yang may be because she's discovered that her reported thrust was anomalous as she tightens up her testing methods. Or not. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/16/2015 07:50 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458535#msg1458535">Quote from: sghill on 12/16/2015 07:45 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458478#msg1458478">Quote from: Rodal on 12/16/2015 06:05 PM</a>
Confirmation of whether or not a new testing campaign will commence at NASA Glenn to replicate the tests at NASA Johnson (Eagleworks), and if so when are the NASA Glenn results expected to be announced/reported.
Remarkably, Yang (in China) has not published any new results for a considerable amount of time, and her last publication dealt with the considerable thermal effects on her experiments (her paper on temperature vs. time measurements throughout a heated EM Drive using embedded thermocouples).
Any announcement that EW is going to Glenn would be wildly major news IMHO because it has to mean that they've seen thrust levels above the noise floor that the Glenn equipment requires before testing there, and also the thrust isn't already attributable to anomalous thrust.
The lack of publishing from Yang may be because she's discovered that her reported thrust was anomalous as she tightens up her testing methods. Or not.
I'll be surprised if NASA Glenn does not proceed to replication testing (to confirm or nullify the Eagleworks tests) . I expect that they will. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rfmwguy on 12/16/2015 08:52 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458540#msg1458540">Quote from: Rodal on 12/16/2015 07:50 PM</a>
Think this is a good supposition, Doc. Hope it happens next year. Been kinda quiet. I can't even get our pal Shell to posts pics...her excuse is she's moving her entire test stand because of the cold...likely story, Doc. She lives in Hawaii, doesn't she? ;)<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458535#msg1458535">Quote from: sghill on 12/16/2015 07:45 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458478#msg1458478">Quote from: Rodal on 12/16/2015 06:05 PM</a>
Confirmation of whether or not a new testing campaign will commence at NASA Glenn to replicate the tests at NASA Johnson (Eagleworks), and if so when are the NASA Glenn results expected to be announced/reported.
Remarkably, Yang (in China) has not published any new results for a considerable amount of time, and her last publication dealt with the considerable thermal effects on her experiments (her paper on temperature vs. time measurements throughout a heated EM Drive using embedded thermocouples).
Any announcement that EW is going to Glenn would be wildly major news IMHO because it has to mean that they've seen thrust levels above the noise floor that the Glenn equipment requires before testing there, and also the thrust isn't already attributable to anomalous thrust.
The lack of publishing from Yang may be because she's discovered that her reported thrust was anomalous as she tightens up her testing methods. Or not.
I'll be surprised if NASA Glenn does not proceed to replication testing (to confirm or nullify the Eagleworks tests) . I expect that they will. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SeeShells on 12/16/2015 10:33 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458576#msg1458576">Quote from: rfmwguy on 12/16/2015 08:52 PM</a>
HA! 2oF this morning going to the doctors. Got back a bit ago, gave a "like" and took a nap. No work done today sorry.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458540#msg1458540">Quote from: Rodal on 12/16/2015 07:50 PM</a>
Think this is a good supposition, Doc. Hope it happens next year. Been kinda quiet. I can't even get our pal Shell to posts pics...her excuse is she's moving her entire test stand because of the cold...likely story, Doc. She lives in Hawaii, doesn't she? ;)<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458535#msg1458535">Quote from: sghill on 12/16/2015 07:45 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458478#msg1458478">Quote from: Rodal on 12/16/2015 06:05 PM</a>
Confirmation of whether or not a new testing campaign will commence at NASA Glenn to replicate the tests at NASA Johnson (Eagleworks), and if so when are the NASA Glenn results expected to be announced/reported.
Remarkably, Yang (in China) has not published any new results for a considerable amount of time, and her last publication dealt with the considerable thermal effects on her experiments (her paper on temperature vs. time measurements throughout a heated EM Drive using embedded thermocouples).
Any announcement that EW is going to Glenn would be wildly major news IMHO because it has to mean that they've seen thrust levels above the noise floor that the Glenn equipment requires before testing there, and also the thrust isn't already attributable to anomalous thrust.
The lack of publishing from Yang may be because she's discovered that her reported thrust was anomalous as she tightens up her testing methods. Or not.
I'll be surprised if NASA Glenn does not proceed to replication testing (to confirm or nullify the Eagleworks tests) . I expect that they will.
The reason it's also taking me a longer time to "get it all back together" is the frustum. I built the drive like Fort Knox. Main reason was to simply to vent the heat from the frustum down a tube to the center of the beam and I had to seal the frustum air tight. As it heats the internal air in the drive can equalize pressures without adding a large thermal ballooning effect right down to the center of the beam. You'll see it in pictures after I get it back together and the mess cleaned up a little. Thought it was time to post this little gem in how to stabilize a thermally expanding frustum balloon.
Shell
PS: The air line comes from the top end seal not the side.
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rfmwguy on 12/16/2015 10:46 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458646#msg1458646">Quote from: SeeShells on 12/16/2015 10:33 PM</a>
Wow, you've taken it up a notch shell...just like we've all suspected...thermal mitigation without a copper mesh...hard to do, but looks like you're onto something...well conceived imho.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458576#msg1458576">Quote from: rfmwguy on 12/16/2015 08:52 PM</a>
HA! 2oF this morning going to the doctors. Got back a bit ago, gave a "like" and took a nap. No work done today sorry.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458540#msg1458540">Quote from: Rodal on 12/16/2015 07:50 PM</a>
Think this is a good supposition, Doc. Hope it happens next year. Been kinda quiet. I can't even get our pal Shell to posts pics...her excuse is she's moving her entire test stand because of the cold...likely story, Doc. She lives in Hawaii, doesn't she? ;)<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458535#msg1458535">Quote from: sghill on 12/16/2015 07:45 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458478#msg1458478">Quote from: Rodal on 12/16/2015 06:05 PM</a>
Confirmation of whether or not a new testing campaign will commence at NASA Glenn to replicate the tests at NASA Johnson (Eagleworks), and if so when are the NASA Glenn results expected to be announced/reported.
Remarkably, Yang (in China) has not published any new results for a considerable amount of time, and her last publication dealt with the considerable thermal effects on her experiments (her paper on temperature vs. time measurements throughout a heated EM Drive using embedded thermocouples).
Any announcement that EW is going to Glenn would be wildly major news IMHO because it has to mean that they've seen thrust levels above the noise floor that the Glenn equipment requires before testing there, and also the thrust isn't already attributable to anomalous thrust.
The lack of publishing from Yang may be because she's discovered that her reported thrust was anomalous as she tightens up her testing methods. Or not.
I'll be surprised if NASA Glenn does not proceed to replication testing (to confirm or nullify the Eagleworks tests) . I expect that they will.
The reason it's also taking me a longer time to "get it all back together" is the frustum. I built the drive like Fort Knox. Main reason was to simply to vent the heat from the frustum down a tube to the center of the beam and I had to seal the frustum air tight. As it heats the internal air in the drive can equalize pressures without adding a large thermal ballooning effect right down to the center of the beam. You'll see it in pictures after I get it back together and the mess cleaned up a little. Thought it was time to post this little gem in how to stabilize a thermally expanding frustum balloon.
Shell
PS: The air line comes from the top end seal not the side. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SeeShells on 12/16/2015 10:59 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458652#msg1458652">Quote from: rfmwguy on 12/16/2015 10:46 PM</a>
Thanks rfmwguy. Got the idea when we were all discussing how to mitigate the balloon heating and thermal rise effect here a couple months ago. It just worked out. Of course I had to seal the very top plate by soldering it on. That was dumb. "Finally" got it apart and I've had to redesign it so I take it apart with some screws from now on.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458646#msg1458646">Quote from: SeeShells on 12/16/2015 10:33 PM</a>
Wow, you've taken it up a notch shell...just like we've all suspected...thermal mitigation without a copper mesh...hard to do, but looks like you're onto something...well conceived imho.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458576#msg1458576">Quote from: rfmwguy on 12/16/2015 08:52 PM</a>
HA! 2oF this morning going to the doctors. Got back a bit ago, gave a "like" and took a nap. No work done today sorry.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458540#msg1458540">Quote from: Rodal on 12/16/2015 07:50 PM</a>
Think this is a good supposition, Doc. Hope it happens next year. Been kinda quiet. I can't even get our pal Shell to posts pics...her excuse is she's moving her entire test stand because of the cold...likely story, Doc. She lives in Hawaii, doesn't she? ;)<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458535#msg1458535">Quote from: sghill on 12/16/2015 07:45 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458478#msg1458478">Quote from: Rodal on 12/16/2015 06:05 PM</a>
Confirmation of whether or not a new testing campaign will commence at NASA Glenn to replicate the tests at NASA Johnson (Eagleworks), and if so when are the NASA Glenn results expected to be announced/reported.
Remarkably, Yang (in China) has not published any new results for a considerable amount of time, and her last publication dealt with the considerable thermal effects on her experiments (her paper on temperature vs. time measurements throughout a heated EM Drive using embedded thermocouples).
Any announcement that EW is going to Glenn would be wildly major news IMHO because it has to mean that they've seen thrust levels above the noise floor that the Glenn equipment requires before testing there, and also the thrust isn't already attributable to anomalous thrust.
The lack of publishing from Yang may be because she's discovered that her reported thrust was anomalous as she tightens up her testing methods. Or not.
I'll be surprised if NASA Glenn does not proceed to replication testing (to confirm or nullify the Eagleworks tests) . I expect that they will.
The reason it's also taking me a longer time to "get it all back together" is the frustum. I built the drive like Fort Knox. Main reason was to simply to vent the heat from the frustum down a tube to the center of the beam and I had to seal the frustum air tight. As it heats the internal air in the drive can equalize pressures without adding a large thermal ballooning effect right down to the center of the beam. You'll see it in pictures after I get it back together and the mess cleaned up a little. Thought it was time to post this little gem in how to stabilize a thermally expanding frustum balloon.
Shell
PS: The air line comes from the top end seal not the side.
I thought about if thermally it wasn't going to do the trick to pipe in another cooling line but so far releasing the pressures in a controlled way where they wouldn't impact by creating a jet of air from the frustum works.
Shell -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rfmwguy on 12/16/2015 11:08 PM -
Been reading the L2 threads a lot, learning all I can as I think Level 2 style and substance will benefit our topic threads. Just some 40,000 foot observations:
1. Posters are well versed in their topics.
2. Posters are well versed in their thread history.
3. I see respectful challenges and equally respectful rebuttals.
4. Info is really fresh, new stuff and little repetition...helpful links posted in that case.
5. "Insider" info where permitted by law. (extra impressed about this)
Obviously L2 is focused on traditional topics where much more is known, but still, there is a lot to aspire towards. Generally though, our speculative topic seems to be keeping the high ground and does mirror some L2 threads...if Doc is right, 2016 testing could bring many here for info...seems we've got a lot of people here that already know how to do the right thing.
/end stream of consciousness since I've not posted much lately. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: glennfish on 12/16/2015 11:47 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458646#msg1458646">Quote from: SeeShells on 12/16/2015 10:33 PM</a>
Main reason was to simply to vent the heat from the frustum down a tube to the center of the beam and I had to seal the frustum air tight. As it heats the internal air in the drive can equalize pressures without adding a large thermal ballooning effect right down to the center of the beam.
Shell,
Granted that you can vector airflow from expansion to where-ever, which should control one thermal effect, what are your thoughts / approach to eliminate lift, i.e. the heated air per volume inside the frustum will weigh less than the cooler air per volume outside? Also, since you will have a variable radius radiator which will create directional airflow on the outside surface, have you control thoughts for that? Your pure thermal source becomes your control for those two thermal factors which you characterize & model before turning on a tuned frustum mag? -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rfmwguy on 12/17/2015 12:14 AM -
Housekeeping note:
Post without commentary and link removed regarding david pares and his experimentation with a warp drive...is not an emdrive, sorry. Also, all offsite links should have commentary preceding them to avoid misunderstanding or misdirection....just a safeguard.
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SeeShells on 12/17/2015 01:05 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458675#msg1458675">Quote from: glennfish on 12/16/2015 11:47 PM</a>
Glen,<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458646#msg1458646">Quote from: SeeShells on 12/16/2015 10:33 PM</a>Main reason was to simply to vent the heat from the frustum down a tube to the center of the beam and I had to seal the frustum air tight. As it heats the internal air in the drive can equalize pressures without adding a large thermal ballooning effect right down to the center of the beam.
Shell,
Granted that you can vector airflow from expansion to where-ever, which should control one thermal effect, what are your thoughts / approach to eliminate lift, i.e. the heated air per volume inside the frustum will weigh less than the cooler air per volume outside? Also, since you will have a variable radius radiator which will create directional airflow on the outside surface, have you control thoughts for that? Your pure thermal source becomes your control for those two thermal factors which you characterize & model before turning on a tuned frustum mag?
The magnetron isn't on the frustum, but in a separate area in it's own Faraday cage cooled by a fan. I'm running the RF power to the waveguides on the frustum with a coax feed down the balance beam. The only heat in the frustum is produced from the RF inside the frustum from the waveguide insertion and heating from the modes. That is much easier to profile. I have a small thermal plume from the frustum but the heated pressure diff (balloon effect) is vented out and down the air line.
I threw together a rough drawing as it can show better than my bad writing.
Shell -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: LancerSolurus on 12/17/2015 01:48 AM - Has anyone tested graphene coated copper test chambers?
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/17/2015 01:58 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458741#msg1458741">Quote from: LancerSolurus on 12/17/2015 01:48 AM</a>
Has anyone tested graphene coated copper test chambers?
No, nobody has reported testing with inner graphene coating.
Prior to that, the first order of business should be to test a ferromagnetic material at one end, as suggested by Fran De Aquino in his paper, who predicts a major improvement:
https://forum.nasaspaceflight.com/index.php?topic=36313.msg1328541#msg1328541
Nobody has reported testing with a ferromagnetic end instead of diamagnetic (copper). -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: ThinkerX on 12/17/2015 02:54 AM -
Ok, we have a number of DIY projects currently underway. The builders are making progress, or at least attempting to deal with the major artifact issues with this device.
Same story with the MEEP modelers.
But, all this means little without a theory of some sort to incorporate/explain the results of these experiments that does not provoke automatic, justifiable dismissal from the mainstream physics community. In my view, of the physicists publically willing to admit to looking into the EM Drive, our own Doctor Rodal is closest to such a theory.
In the past, there have been multiple piecemeal suggestions for the DIY types and MEEP modelers. However, this is a scattershot approach at best.
Therefor, I suggest that Doctor Rodal - or another qualified physicist - put forth a list of experiments he would like to see the DIY and MEEP types attempt, keeping in mind the restrictions these people are working under. A sort of 'checklist' that might at least establish a bit of uniformity between the different designs and models.
I would suggest this list, once compiled, be added to the Wiki and our new EM Driven site. Something to provide a bit of guidance for the experimenters.
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: OnlyMe on 12/17/2015 03:15 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458773#msg1458773">Quote from: ThinkerX on 12/17/2015 02:54 AM</a>
Ok, we have a number of DIY projects currently underway. The builders are making progress, or at least attempting to deal with the major artifact issues with this device.
Same story with the MEEP modelers.
But, all this means little without a theory of some sort to incorporate/explain the results of these experiments that does not provoke automatic, justifiable dismissal from the mainstream physics community. In my view, of the physicists publically willing to admit to looking into the EM Drive, our own Doctor Rodal is closest to such a theory.
In the past, there have been multiple piecemeal suggestions for the DIY types and MEEP modelers. However, this is a scattershot approach at best.
Therefor, I suggest that Doctor Rodal - or another qualified physicist - put forth a list of experiments he would like to see the DIY and MEEP types attempt, keeping in mind the restrictions these people are working under. A sort of 'checklist' that might at least establish a bit of uniformity between the different designs and models.
I would suggest this list, once compiled, be added to the Wiki and our new EM Driven site. Something to provide a bit of guidance for the experimenters.
This is a good long game plan, but as an observer on the sidelines, it seems to me that the best approach would be to first work out just what is required to reproduce thrust at the levels claimed by Shawyer and Yang. Since everyone including Eagleworks is really starting from scratch, neither Shawyer or Yang provide enough detail to reproduce their frustums and microwave sources, having an idea how to deal with the systemic and heat related issues is good, but it is a waste of time and money until you have a decent frustum that does produce enough thrust that it is even possible to try and rule out noise.
As a separate issue, it really seems from what limited information I have gone through at present, that until someone is able to scale up the delivered power to several hundred watts resononating, you may not get the kind of thrust in either of the earlier claims.
Basically I guess what I am saying is that because the DIYs are working in atmosphere and with limited resources, it will require a thrust in at least tens of mNs before any practical elimination of thermal and systemic effects will be practical.
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: zen-in on 12/17/2015 06:14 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458780#msg1458780">Quote from: OnlyMe on 12/17/2015 03:15 AM</a>
...
This is a good long game plan, but as an observer on the sidelines, it seems to me that the best approach would be to first work out just what is required to reproduce thrust at the levels claimed by Shawyer and Yang. Since everyone including Eagleworks is really starting from scratch, neither Shawyer or Yang provide enough detail to reproduce their frustums and microwave sources, having an idea how to deal with the systemic and heat related issues is good, but it is a waste of time and money until you have a decent frustum that does produce enough thrust that it is even possible to try and rule out noise.
As a separate issue, it really seems from what limited information I have gone through at present, that until someone is able to scale up the delivered power to several hundred watts resononating, you may not get the kind of thrust in either of the earlier claims.
Basically I guess what I am saying is that because the DIYs are working in atmosphere and with limited resources, it will require a thrust in at least tens of mNs before any practical elimination of thermal and systemic effects will be practical.
This has been discussed before. Using several hundred Watts does not make the thermal response any less significant. It appears that at every power level thermal effects are greater than any indication of thrust. In the absence of any information from Yang or Shawyer that could be used to replicate their apparatus and independently confirm their results, the best that can be done is to build something close and test it. If this em-drive force does exist it would eventually be seen by some other experimenter even without knowing exactly what Shawyer or Yang did. Science has been down this path before. If the phenomena cannot be demonstrated, it doesn't exist.
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: ThinkerX on 12/17/2015 07:41 AM -
Quote
This has been discussed before. Using several hundred Watts does not make the thermal response any less significant. It appears that at every power level thermal effects are greater than any indication of thrust. In the absence of any information from Yang or Shawyer that could be used to replicate their apparatus and independently confirm their results, the best that can be done is to build something close and test it. If this em-drive force does exist it would eventually be seen by some other experimenter even without knowing exactly what Shawyer or Yang did. Science has been down this path before. If the phenomena cannot be demonstrated, it doesn't exist.
Hence my proposal: a set of standardized experiments to be performed, if possible by the DIY types. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: ZhixianLin on 12/17/2015 08:28 AM -
Hey, why not try my design. I think it is easier to understand.
Here it is:
http://forum.nasaspaceflight.com/index.php?topic=38996.0 -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/17/2015 11:49 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457889#msg1457889">Quote from: Tellmeagain on 12/15/2015 04:49 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457877#msg1457877">Quote from: Rodal on 12/15/2015 04:39 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1457874#msg1457874">Quote from: CraigPichach on 12/15/2015 04:36 PM</a>
An update on our 100kW test project. Model using HFSS using eigenmode solver, TE013 mode 914.85MHz Q=133526. Loop coupled design for ease of build, cost and stress concerns.
As we are planning to use a high power coax line and are designing as a pressure vessel, one recommendation is to use copper cladded stainless steel... does anyone see any objections to the use of this material so long as we clad the internals with copper? This would help us with vessel integrity and cooling; while I do think we will achieve resonance is there any EM-Drive Q thruster theories that say not to do this (i.e. impacting the quantum vacuum??).
It is noteworthy to remark that this is the ONLY test by anyone (as far as I know) where there is a deliberate attempt to test for anomalous thrust forces that are way beyond the forces produced by thermal effects.
Assuming the frustum is resonating with 100KW input, won't we see 100KW of heat generated by the furstum? If we see 100W heat only, we can only assume that 99.9% power are reflected back and this test is no better than a 100W test.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458814#msg1458814">Quote from: zen-in on 12/17/2015 06:14 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458780#msg1458780">Quote from: OnlyMe on 12/17/2015 03:15 AM</a>
...
This is a good long game plan, but as an observer on the sidelines, it seems to me that the best approach would be to first work out just what is required to reproduce thrust at the levels claimed by Shawyer and Yang. Since everyone including Eagleworks is really starting from scratch, neither Shawyer or Yang provide enough detail to reproduce their frustums and microwave sources, having an idea how to deal with the systemic and heat related issues is good, but it is a waste of time and money until you have a decent frustum that does produce enough thrust that it is even possible to try and rule out noise.
As a separate issue, it really seems from what limited information I have gone through at present, that until someone is able to scale up the delivered power to several hundred watts resononating, you may not get the kind of thrust in either of the earlier claims.
Basically I guess what I am saying is that because the DIYs are working in atmosphere and with limited resources, it will require a thrust in at least tens of mNs before any practical elimination of thermal and systemic effects will be practical.
This has been discussed before. Using several hundred Watts does not make the thermal response any less significant. It appears that at every power level thermal effects are greater than any indication of thrust. In the absence of any information from Yang or Shawyer that could be used to replicate their apparatus and independently confirm their results, the best that can be done is to build something close and test it. If this em-drive force does exist it would eventually be seen by some other experimenter even without knowing exactly what Shawyer or Yang did. Science has been down this path before. If the phenomena cannot be demonstrated, it doesn't exist.
It should not be assumed that the thermal effects will scale linearly with input power, on the contrary:
1) While Maxwell's equations are linear, the Navier Stokes equations of fluid dynamics governing thermal natural convection (lift and drag effect due to air heating) are nonlinear. The tendency of the naturally convective thermal system towards turbulence relies on the Grashof number, which goes like the cube of the characteristic length and the inverse of the square of the kinematic viscosity. It can be thought of as Reynolds number with the velocity of natural convection replacing the velocity in Reynolds number's formula. Natural convection is highly dependent on the geometry of the hot surface, a general correlation that applies for a variety of geometries shows the Nusselt number to be a nonlinear function of the Prandtl number and a nonlinear function of the Reynolds number.
2) The experimental results of Prof. Yang showed strong nonlinearity between the measured force and the input power (see attached chart). Prof. Yang's experiments show diminishing returns (actually slight decrease in measured forces for input power exceeding 300 Watts and general flat response) for increasing input power.
Hence it does not follow that the thermal artifacts will scale linearly in experiments conducted at much higher input power. On the contrary, Prof. Yang's experimental results show strong nonlinearity, with the touted "EM Drive" force dependence on input power effectively dissappearing after about 300 watts, the dependence looks practically flat at input powers greater than 300 W. The nonlinearity of the "force" vs. input power experimental relation of Prof. Yang has not yet been scientifically modeled hence its nature can only be speculated until a verifiable model is demonstrated.
This shows that if anything, experiments conducted at ambient conditions with low power may be highly misleading and NOT linearly scalable to higher powers, just as it would be highly misleading to conflate the flight of an insect with the flight of an airplane (the aerodynamics are completely different at very low Reynolds numbers).(The range of Reynolds number in insect flight is about 10 to 10^4, which lies in between the two limits that are convenient for theories that try to simplify the nonlinearity of Navier Stokes fluid dynamics: inviscid steady flows around an airplane's airfoil and Stokes flow experienced by a swimming bacterium. For this reason, this intermediate Reynolds number range used by insects in their flight is not as well understood as the high Reynolds number regime for airplanes. )
Before the Wright Brothers flying machine, there were lots of experimenters trying to make flying machines fly similarly to the way insects or small birds fly. Those experiments resulted in utter failure.
https://www.youtube.com/watch?v=gN-ZktmjIfE
Instead of trying to model the flight of an insect, the Wright Brothers built their own wind tunnel and addressed the problems associated with flight of machines that could carry people rather than insects. In that sense, the Wright Brothers understood that the Navier-Stokes equations describing fluid dynamics are nonlinear equations.
Of course, the best way to eliminate this pesky influence of the surrounding air is to conduct the tests in a vacuum chamber, as done by Tajmar at TU Dresden and NASA Eagleworks, which resulted in measured "EM Drive forces" that are orders of magnitude smaller than the forces claimed by Shawyer and Yang in their experiments (all of them conducted in air).
It is very noteworthy that neither Yang nor Shawyer have reported a single EM Drive experiment in vacuum. Instead of asking Boeing whether they are still working with Shawyer, (which we know from both Boeing and Shawyer, no longer working with each other), I would ask Boeing what were Boeing results of the EM Drive tests in vacuum, as the Boeing/Shawyer arrangement was supposed to eventually lead to testing of a satellite in the vacuum of space, and Boeing had ready availability of vacuum chambers to conduct such a test -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Tellmeagain on 12/17/2015 12:33 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458535#msg1458535">Quote from: sghill on 12/16/2015 07:45 PM</a>
Any announcement that EW is going to Glenn would be wildly major news IMHO because it has to mean that they've seen thrust levels above the noise floor that the Glenn equipment requires before testing there, and also the thrust isn't already attributable to anomalous thrust.
The lack of publishing from Yang may be because she's discovered that her reported thrust was anomalous as she tightens up her testing methods. Or not.
I think your understanding of "anomalous thrust" is different from the majority of people here. Only those that can not be explained by existing physics are anomalous. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Tellmeagain on 12/17/2015 12:40 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458478#msg1458478">Quote from: Rodal on 12/16/2015 06:05 PM</a>
The last institutional published experimental report was by Tajmar at the Technische Universität Dresden in Germany.
We are waiting to hear news from NASA regarding:
1) Publication of NASA's Eagleworks EM Drive tests performed in vacuum, including discussion/analysis of thermal expansion effects and effects from forces resulting from the magnetic damper.
2) Confirmation of whether or not a new testing campaign will commence at NASA Glenn to replicate the tests at NASA Johnson (Eagleworks), and if so when are the NASA Glenn results expected to be announced/reported.
Remarkably, Yang (in China) has not published any new results for a considerable amount of time, and her last publication dealt with the considerable thermal effects on her experiments (her paper on temperature vs. time measurements throughout a heated EM Drive using embedded thermocouples).
Concerning Do-It-Yourself experiments, the last experimental report was by RFMWGUY. We are waiting to hear from Shell on her meticulously and thoroughly designed testing program.
The abstract deadline for 52nd AIAA/SAE/ASEE Joint Propulsion Conference http://www.aiaa-propulsionenergy.org/JPC/ is Jan 12th, 2016. Hurry up NASA!
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: glennfish on 12/17/2015 12:42 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458721#msg1458721">Quote from: SeeShells on 12/17/2015 01:05 AM</a>
I have a small thermal plume from the frustum but the heated pressure diff (balloon effect) is vented out and down the air line.
Shell
Shell,
I'm following you, but perhaps I'm not explaining myself. I see three thermal effects.
1. Air venting from the frustum, which you're managing
2. Air density within the frustum, which cannot be vented. Hot air is lighter than cold air at the same pressure (no venting changes that)
3. The conical exterior wall heating will set up different air flow rates between the narrow and wide ends, effects dependent upon frustum orientation.
I don't know how to design out the latter two.
I just want to be sure I understand your constraints.
if I'm right, it doesn't matter, provided you incorporate those effects into your test protocol. I'm pretty convinced that any thrust greater than zero can be observed statistically with the right protocol even if these effects aren't compensated for in the physical design.
Just want to be sure I understand what you can and can't do, have and haven't done. Once you start grabbing data, I expect to be tossing test methods over the wall like a whirling dervish. Having a list of what's not compensated for leads to tests to characterize those items, which makes anomalous effects easier to see. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/17/2015 12:51 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458941#msg1458941">Quote from: glennfish on 12/17/2015 12:42 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458721#msg1458721">Quote from: SeeShells on 12/17/2015 01:05 AM</a>
I have a small thermal plume from the frustum but the heated pressure diff (balloon effect) is vented out and down the air line.
Shell
Shell,
I'm following you, but perhaps I'm not explaining myself. I see three thermal effects.
1. Air venting from the frustum, which you're managing
2. Air density within the frustum, which cannot be vented. Hot air is lighter than cold air at the same pressure (no venting changes that)
3. The conical exterior wall heating will set up different air flow rates between the narrow and wide ends, effects dependent upon frustum orientation.
I don't know how to design out the latter two.
I just want to be sure I understand your constraints.
if I'm right, it doesn't matter, provided you incorporate those effects into your test protocol. I'm pretty convinced that any thrust greater than zero can be observed statistically with the right protocol even if these effects aren't compensated for in the physical design.
Just want to be sure I understand what you can and can't do, have and haven't done. Once you start grabbing data, I expect to be tossing test methods over the wall like a whirling dervish. Having a list of what's not compensated for leads to tests to characterize those items, which makes anomalous effects easier to see.
Statistical correlation does not imply causation. This is particularly so when the sample size of the statistical population is so small as in RFMWGUY's experiments. The results of the statistical tests may just be governed and explained by classical physics, as per transient thermal convection lift and drag effects of the heated magnetron in RFMWGUY's experiment. Therefore mathematical physics analysis cannot be substituted by statistical analysis and your point is well taken that these issues need to be analyzed with mathematical physics. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: OnlyMe on 12/17/2015 01:04 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458814#msg1458814">Quote from: zen-in on 12/17/2015 06:14 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458780#msg1458780">Quote from: OnlyMe on 12/17/2015 03:15 AM</a>
.....
Basically I guess what I am saying is that because the DIYs are working in atmosphere and with limited resources, it will require a thrust in at least tens of mNs before any practical elimination of thermal and systemic effects will be practical.
This has been discussed before. Using several hundred Watts does not make the thermal response any less significant. It appears that at every power level thermal effects are greater than any indication of thrust. In the absence of any information from Yang or Shawyer that could be used to replicate their apparatus and independently confirm their results, the best that can be done is to build something close and test it. If this em-drive force does exist it would eventually be seen by some other experimenter even without knowing exactly what Shawyer or Yang did. Science has been down this path before. If the phenomena cannot be demonstrated, it doesn't exist.
I believe that was essentially my point. Build a frustum/microwave source that generates a thrust sufficient, that it is even practical to try and start eliminating.... Spending too much time and money to eliminate systemic and thermal effects before you have a system that generates enough thrust to work with, does not seem a good use of resources.
With unlimited funding and/or a vacuum chamber, chasing the noise before you have demonstrated thrust is wasteful. It would be different if you were duplicating something Shawyer or Yang already constructed, but if that were possible you would not see everyone, starting out with different system designs. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rfmwguy on 12/17/2015 01:19 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458943#msg1458943">Quote from: Rodal on 12/17/2015 12:51 PM</a>
We have 2 approaches for thermal mitigation; statistical and mathematical physics. I think this is excellent. Statistical is more straight forward, but the latter is not. We have several possible ways to look at the latter and I have heard fluid dynamics proposed, but I don't see a way mere mortals (DIYers) can do this.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458941#msg1458941">Quote from: glennfish on 12/17/2015 12:42 PM</a>
(...) Therefore mathematical physics analysis cannot be substituted by statistical analysis and your point is well taken that these issues need to be analyzed with mathematical physics.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458721#msg1458721">Quote from: SeeShells on 12/17/2015 01:05 AM</a>I have a small thermal plume from the frustum but the heated pressure diff (balloon effect) is vented out and down the air line.
Shell
(...)Just want to be sure I understand what you can and can't do, have and haven't done. Once you start grabbing data, I expect to be tossing test methods over the wall like a whirling dervish. Having a list of what's not compensated for leads to tests to characterize those items, which makes anomalous effects easier to see.
So, I propose if statistical AND the latter are going to be required moving forward for ambient air testing, we need a concensus and a pathway with specifics. Anything you brain trusts can do to set up standards, I propose that Shell tries these out (sorry, pal)...or wait for me sometime in June of next year. The sooner the better IMHO.
If fluid dynamics modeling is out of the picture, what is possible? -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: glennfish on 12/17/2015 01:20 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458943#msg1458943">Quote from: Rodal on 12/17/2015 12:51 PM</a>
Statistical correlation does not imply causation. This is particularly so when the sample size of the statistical population is small, as in RFMWGUY's experiments. The results of the statistical tests may just be governed and explained by classical physics, as per transient thermal convection lift and drag effects of the heated magnetron. Therefore mathematical physics analysis cannot be substituted by statistical analysis and your point is well taken that these issues need to be analyzed with mathematical physics.
Absolutely agree.
From my point of view, there is a universe of noise sources that has to be characterized.
There may be a signal in the noise.
If the noise is understood, then we can set up a trials methodology that will indicate signal if the signal is > than some threshold. The # of trials to achieve statistical significance depends on the amplitude of the noise, the amplitude of the signal, the random variations in both and a list of other things that need to be itemized.
Attached is a simulation I provided Shell earlier of how visible a signal would be under various constraints. For now, I want to be sure I understand her constraints so the simulation can be adapted accordingly, which will lead to a trials methodology. Cells in yellow can be changed to suit various assumptions.
Right now, it looks like the simulation is missing some factors for consideration, hence my questions to her.
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: OnlyMe on 12/17/2015 01:22 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458943#msg1458943">Quote from: Rodal on 12/17/2015 12:51 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458941#msg1458941">Quote from: glennfish on 12/17/2015 12:42 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458721#msg1458721">Quote from: SeeShells on 12/17/2015 01:05 AM</a>
I have a small thermal plume from the frustum but the heated pressure diff (balloon effect) is vented out and down the air line.
Shell
Shell,
I'm following you, but perhaps I'm not explaining myself. I see three thermal effects.
1. Air venting from the frustum, which you're managing
2. Air density within the frustum, which cannot be vented. Hot air is lighter than cold air at the same pressure (no venting changes that)
3. The conical exterior wall heating will set up different air flow rates between the narrow and wide ends, effects dependent upon frustum orientation.
I don't know how to design out the latter two.
I just want to be sure I understand your constraints.
if I'm right, it doesn't matter, provided you incorporate those effects into your test protocol. I'm pretty convinced that any thrust greater than zero can be observed statistically with the right protocol even if these effects aren't compensated for in the physical design.
Just want to be sure I understand what you can and can't do, have and haven't done. Once you start grabbing data, I expect to be tossing test methods over the wall like a whirling dervish. Having a list of what's not compensated for leads to tests to characterize those items, which makes anomalous effects easier to see.
Statistical correlation does not imply causation. This is particularly so when the sample size of the statistical population is small, as in RFMWGUY's experiments. The results of the statistical tests may just be governed and explained by classical physics, as per transient thermal convection lift and drag effects of the heated magnetron. Therefore mathematical physics analysis cannot be substituted by statistical analysis and your point is well taken that these issues need to be analyzed with mathematical physics.
The portion in my bold emphasis above is just what I was referring too. If you don't have enough anomalous thrust to work with.., or a vacuum chanmber.., you don't have enough to work with.
There have been some good ideas on just how some of the thermal effect might be handled. Most of the time they would require additional engineering, which requires funding.., and may introduce other systemic issues.
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: OnlyMe on 12/17/2015 01:34 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458954#msg1458954">Quote from: rfmwguy on 12/17/2015 01:19 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458943#msg1458943">Quote from: Rodal on 12/17/2015 12:51 PM</a>
We have 2 approaches for thermal mitigation; statistical and mathematical physics. I think this is excellent. Statistical is more straight forward, but the latter is not. We have several possible ways to look at the latter and I have heard fluid dynamics proposed, but I don't see a way mere mortals (DIYers) can do this.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458941#msg1458941">Quote from: glennfish on 12/17/2015 12:42 PM</a>
(...) Therefore mathematical physics analysis cannot be substituted by statistical analysis and your point is well taken that these issues need to be analyzed with mathematical physics.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458721#msg1458721">Quote from: SeeShells on 12/17/2015 01:05 AM</a>I have a small thermal plume from the frustum but the heated pressure diff (balloon effect) is vented out and down the air line.
Shell
(...)Just want to be sure I understand what you can and can't do, have and haven't done. Once you start grabbing data, I expect to be tossing test methods over the wall like a whirling dervish. Having a list of what's not compensated for leads to tests to characterize those items, which makes anomalous effects easier to see.
So, I propose if statistical AND the latter are going to be required moving forward for ambient air testing, we need a concensus and a pathway with specifics. Anything you brain trusts can do to set up standards, I propose that Shell tries these out (sorry, pal)...or wait for me sometime in June of next year. The sooner the better IMHO.
If fluid dynamics modeling is out of the picture, what is possible?
Didn't Tajmar put the frustum in a box filled with fiberglass to reduce or eliminate thermal convection effects? That should be doable with Shell's design.., if she has enough raw thrust to make it worth the effort.
Another approach, potentially possible with a fully sealed frustum, might be to evacuate the frustum itself. As long as the frustum is ridged enough in design, that should eliminate or at least significantly reduce ballooning... And might be possible with a less expensive vacuum pump than required for a vacuum chamber.
There are many things that might be possible for a DIY experiment.., IF the thrust seen is enough to warrant the investment in additional time and money. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/17/2015 01:41 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458960#msg1458960">Quote from: OnlyMe on 12/17/2015 01:34 PM</a>
Yes, but when Tajmar performed the experiments in vacuum he measured much smaller forces, therefore this showed that the box did not solve the thermal artifacts caused by air.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458954#msg1458954">Quote from: rfmwguy on 12/17/2015 01:19 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458943#msg1458943">Quote from: Rodal on 12/17/2015 12:51 PM</a>
We have 2 approaches for thermal mitigation; statistical and mathematical physics. I think this is excellent. Statistical is more straight forward, but the latter is not. We have several possible ways to look at the latter and I have heard fluid dynamics proposed, but I don't see a way mere mortals (DIYers) can do this.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458941#msg1458941">Quote from: glennfish on 12/17/2015 12:42 PM</a>
(...) Therefore mathematical physics analysis cannot be substituted by statistical analysis and your point is well taken that these issues need to be analyzed with mathematical physics.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458721#msg1458721">Quote from: SeeShells on 12/17/2015 01:05 AM</a>I have a small thermal plume from the frustum but the heated pressure diff (balloon effect) is vented out and down the air line.
Shell
(...)Just want to be sure I understand what you can and can't do, have and haven't done. Once you start grabbing data, I expect to be tossing test methods over the wall like a whirling dervish. Having a list of what's not compensated for leads to tests to characterize those items, which makes anomalous effects easier to see.
So, I propose if statistical AND the latter are going to be required moving forward for ambient air testing, we need a concensus and a pathway with specifics. Anything you brain trusts can do to set up standards, I propose that Shell tries these out (sorry, pal)...or wait for me sometime in June of next year. The sooner the better IMHO.
If fluid dynamics modeling is out of the picture, what is possible?
Didn't Tajmar put the frustum in a box filled with fiberglass to reduce or eliminate thermal convection effects? That should be doable with Shell's design.., if she has enough raw thrust to make it worth the effort.
Another approach, potentially possible with a fully sealed frustum, might be to evacuate the frustum itself. As long as the frustum is ridged enough in design, that should eliminate or at least significantly reduce ballooning... And might be possible with a less expensive vacuum pump than required for a vacuum chamber.
There are many things that might be possible for a DIY experiment.., IF the thrust seen is enough to warrant the investment in additional time and money.
As usual with all these experimenters, Tajmar did NOT conduct a Computational Fluid Dynamics simulation, so the "box" concept was not scientifically analyzed, and his vacuum experiments showed the "box" to not have effectively addressed the air convection effects.
Such "solutions" as the "box" are based on intuition rather than analysis. Hence it is not too surprising that actual experiments show them to be ineffective. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rfmwguy on 12/17/2015 01:55 PM -
OK, here's something from left field...a visualization of fluid dynamics, or:
https://en.wikipedia.org/wiki/Schlieren_photography
Lets say we video a static frustum using Schlieren lenses, get a proper scale reference, temperature, humidity and plume velocity...could we effectively predict thermal-dynamic forces? -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/17/2015 02:12 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458975#msg1458975">Quote from: rfmwguy on 12/17/2015 01:55 PM</a>
OK, here's something from left field...a visualization of fluid dynamics, or:
Not enough for a quantitative prediction (it would not eliminate the need for a Computational Fluid Dynamics simulation), but it would elucidate what is going on more than present experiments conducted in air based on intuition rather than fluid dynamics analysis:
https://en.wikipedia.org/wiki/Schlieren_photography
Lets say we video a static frustum using Schlieren lenses, get a proper scale reference, temperature, humidity and plume velocity...could we effectively predict thermal-dynamic forces?
https://www.youtube.com/watch?v=gE9Omyg6gIE
It would be particularly useful if it could be accurately monitored with accurate clock timing (or some other means to show the magnetron going ON and OFF in the Schlieren movie) to show what happens for example, whenever the magnetron is turned ON and OFF (rather than assuming without computational fluid dynamics analysis that turning the magnetron on will result in lift rather than drag under an existing thermal lift force) -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rfmwguy on 12/17/2015 02:17 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458983#msg1458983">Quote from: Rodal on 12/17/2015 02:12 PM</a>
I can do this, but it is a moderate cost to get the 2 lenses. I'd prefer not doing it if there is no quantitative value. IOW, it might be nice to see, but if it cannot be used as a predictor for thermodynamic movement, not sure the expense is warranted. This is what stopped me from doing this recently...I could not justify the expense if it wouldn't contribute to the dataset...if that makes sense...<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458975#msg1458975">Quote from: rfmwguy on 12/17/2015 01:55 PM</a>OK, here's something from left field...a visualization of fluid dynamics, or:
Not enough for a quantitative prediction, but it would elucidate what is going on more than present experiments
https://en.wikipedia.org/wiki/Schlieren_photography
Lets say we video a static frustum using Schlieren lenses, get a proper scale reference, temperature, humidity and plume velocity...could we effectively predict thermal-dynamic forces?
https://www.youtube.com/watch?v=gE9Omyg6gIE
It would be particularly useful if it could be accurately monitored with accurate clock timing to show what happens for example, whenever the magnetron is turned ON and OFF (rather than assuming without analysis that turning the magnetron on will result in lift rather than drag under an existing thermal lift force) -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/17/2015 02:19 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458984#msg1458984">Quote from: rfmwguy on 12/17/2015 02:17 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458983#msg1458983">Quote from: Rodal on 12/17/2015 02:12 PM</a>
I can do this, but it is a moderate cost to get the 2 lenses. I'd prefer not doing it if there is no quantitative value. IOW, it might be nice to see, but if it cannot be used as a predictor for thermodynamic movement, not sure the expense is warranted. This is what stopped me from doing this recently...I could not justify the expense if it wouldn't contribute to the dataset...if that makes sense...<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458975#msg1458975">Quote from: rfmwguy on 12/17/2015 01:55 PM</a>OK, here's something from left field...a visualization of fluid dynamics, or:
Not enough for a quantitative prediction, but it would elucidate what is going on more than present experiments
https://en.wikipedia.org/wiki/Schlieren_photography
Lets say we video a static frustum using Schlieren lenses, get a proper scale reference, temperature, humidity and plume velocity...could we effectively predict thermal-dynamic forces?
https://www.youtube.com/watch?v=gE9Omyg6gIE
It would be particularly useful if it could be accurately monitored with accurate clock timing to show what happens for example, whenever the magnetron is turned ON and OFF (rather than assuming without analysis that turning the magnetron on will result in lift rather than drag under an existing thermal lift force)
Would you be able to accurately tie what is shown in the Schlieren movie to the actual timing of the turning ON and OFF of the magnetron ? -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rfmwguy on 12/17/2015 02:27 PM -
Doc,
Yes, a video would both have a timer and contain audio to denote mag on (xformer hum).
Also, I could embed a spectrum analyzer display in the corner to show freq locking, which would probably be a better indication of start.
Plume temp would be hard to measure with my IR thermometer...can get a case temp or sync a thermal vid. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/17/2015 02:29 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458992#msg1458992">Quote from: rfmwguy on 12/17/2015 02:27 PM</a>
Doc,
Yes, a video would both have a timer and contain audio to denote mag on (xformer hum).
Also, I could imbed a spectrum analyzer display in the corner to show freq locking, which would probably be a better indication of start.
Plume temp would be hard to measure with my IR thermometer...can get a case temp or sync a thermal vid.
Accurately synchronizing the Schlieren movie to the turning on and off the magnetron is the big issue...
Maybe readers can point out what would be the most accurate synchronization between a movie and actual timing of the Magnetron turning ON and OFF...
It seems to me that the best way would be to have a signal showing the magnetron going ON and OFF in the movie itself (this would eliminate any errors due to the movie marching in time at a different, or non-monotonic rate than an external accurate clock). -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: VAXHeadroom on 12/17/2015 03:03 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458997#msg1458997">Quote from: Rodal on 12/17/2015 02:29 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458992#msg1458992">Quote from: rfmwguy on 12/17/2015 02:27 PM</a>
Doc,
Yes, a video would both have a timer and contain audio to denote mag on (xformer hum).
Also, I could imbed a spectrum analyzer display in the corner to show freq locking, which would probably be a better indication of start.
Plume temp would be hard to measure with my IR thermometer...can get a case temp or sync a thermal vid.
Accurately synchronizing the Schlieren movie to the turning on and off the magnetron is the big issue...
Maybe readers can point out what would be the most accurate synchronization between a movie and actual timing of the Magnetron turning ON and OFF...
It seems to me that the best way would be to have a signal showing the magnetron going ON and OFF in the movie itself (this would eliminate any errors due to the movie marching in time at a different, or non-monotonic rate than an external accurate clock).
Tap a current sensor off the magnetron's electronic feed circuit and either turn a light on or just put an ammeter in the video. This would show when there's actually power going to the magnetron. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rfmwguy on 12/17/2015 03:15 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459023#msg1459023">Quote from: VAXHeadroom on 12/17/2015 03:03 PM</a>
Good ideas, but a spectrum spike of RF would show when the power was locked into a stable output...think this would do it. The Schlieren vid could have a small window on the same screen showing the spectrum...I would do a simple screen record of both videos simultaneously...<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458997#msg1458997">Quote from: Rodal on 12/17/2015 02:29 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458992#msg1458992">Quote from: rfmwguy on 12/17/2015 02:27 PM</a>Doc,
Yes, a video would both have a timer and contain audio to denote mag on (xformer hum).
Also, I could imbed a spectrum analyzer display in the corner to show freq locking, which would probably be a better indication of start.
Plume temp would be hard to measure with my IR thermometer...can get a case temp or sync a thermal vid.
Accurately synchronizing the Schlieren movie to the turning on and off the magnetron is the big issue...
Maybe readers can point out what would be the most accurate synchronization between a movie and actual timing of the Magnetron turning ON and OFF...
It seems to me that the best way would be to have a signal showing the magnetron going ON and OFF in the movie itself (this would eliminate any errors due to the movie marching in time at a different, or non-monotonic rate than an external accurate clock).
Tap a current sensor off the magnetron's electronic feed circuit and either turn a light on or just put an ammeter in the video. This would show when there's actually power going to the magnetron. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/17/2015 03:35 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459023#msg1459023">Quote from: VAXHeadroom on 12/17/2015 03:03 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458997#msg1458997">Quote from: Rodal on 12/17/2015 02:29 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458992#msg1458992">Quote from: rfmwguy on 12/17/2015 02:27 PM</a>
Doc,
Yes, a video would both have a timer and contain audio to denote mag on (xformer hum).
Also, I could imbed a spectrum analyzer display in the corner to show freq locking, which would probably be a better indication of start.
Plume temp would be hard to measure with my IR thermometer...can get a case temp or sync a thermal vid.
Accurately synchronizing the Schlieren movie to the turning on and off the magnetron is the big issue...
Maybe readers can point out what would be the most accurate synchronization between a movie and actual timing of the Magnetron turning ON and OFF...
It seems to me that the best way would be to have a signal showing the magnetron going ON and OFF in the movie itself (this would eliminate any errors due to the movie marching in time at a different, or non-monotonic rate than an external accurate clock).
Tap a current sensor off the magnetron's electronic feed circuit and either turn a light on or just put an ammeter in the video. This would show when there's actually power going to the magnetron.
Is the proposal thatQuoteThe Schlieren vid could have a small window on the same screen showing the spectrum
just as concurrently synchronized as showing the ammeter in one and the same same Schlieren video? or does windowing of separate videos (one video for the spectrum and another video for the Shlieren optical view) introduce synchronization issues between the windowed videos?
(Separate window processes on a computer do not necessarily run concurrently, so is just a practical issue of whether the timing differences (and their accumulated effect) between the windows are or are not negligible for the experimental purposes) -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rfmwguy on 12/17/2015 03:40 PM -
Current would be OK, but the mag does not necessarily "lock" until it comes up to temp and stabilizes. This is why I proposed a spec an spike to show its lock mode rather than a current sampling. Anytime the RF peaks, it would show lock and it would be synchronized with the Schlieren video...simply overlaid on top and a screen recorder would make the combined video.
Sooo, Schlieren video runs on laptop, overlaid with a small spec analyzer display (also running in real time). Screen record video captures both in real time...make sense? -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rfmwguy on 12/17/2015 03:52 PM -
OK, Doc, CEJ posted this on T5 and I forgot about it:
http://forum.nasaspaceflight.com/index.php?topic=38577.msg1441327;topicseen#msg1441327
http://people.csail.mit.edu/tfxue/proj/fluidflow/
You're an MIT guy...give me your thoughts about their software! -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/17/2015 04:02 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459052#msg1459052">Quote from: rfmwguy on 12/17/2015 03:52 PM</a>
OK, Doc, CEJ posted this on T5 and I forgot about it:
The author was in the Electrical Engineering Department Course Vi, and just concludes
http://forum.nasaspaceflight.com/index.php?topic=38577.msg1441327;topicseen#msg1441327
http://people.csail.mit.edu/tfxue/proj/fluidflow/
You're an MIT guy...give me your thoughts about their software!Quoteprovide promising evidence that refractive fluids can be analyzed in natural settings, which can make fluid flow measurement cheaper and more accessible
So, I trust that it is indeed "promising" which is what the author concludes.
The next step would be to verify whether these new algorithms and method have been embraced by the Fluid Mechanics community (in the Aeronautics and Astronautics Course XVI and Mechanical Engineering Course II departments at MIT) or by the academic fluid mechanics community in general that have been using other methods. Everything in science and engineering is a question of independent duplication of experiments and peer review to verify how robust and precise are such cheaper techniques.
Of course Schleiren optical methods have been embraced by the Fluid Mechanics community for a century. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rfmwguy on 12/17/2015 04:11 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459057#msg1459057">Quote from: Rodal on 12/17/2015 04:02 PM</a>
So Doc, can I count on you to take the next step? ::) I'll volunteer to get the gear and do the test IF you think its worthwhile.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459052#msg1459052">Quote from: rfmwguy on 12/17/2015 03:52 PM</a>OK, Doc, CEJ posted this on T5 and I forgot about it:
The author was in the Electrical Engineering Department Course Vi, and just concludes
http://forum.nasaspaceflight.com/index.php?topic=38577.msg1441327;topicseen#msg1441327
http://people.csail.mit.edu/tfxue/proj/fluidflow/
You're an MIT guy...give me your thoughts about their software!Quoteprovide promising evidence that refractive fluids can be analyzed in natural settings, which can make fluid flow measurement cheaper and more accessible
So, I trust that it is indeed "promising" which is what the author concludes.
The next step would be to verify whether these new algorithms and method have been embraced by the Fluid Mechanics community (in the Aeronautics and Astronautics Course XVI and Mechanical Engineering Course II departments at MIT) or by the academic fluid mechanics community in general. Everything in science and engineering is a question of independent duplication of experiments and peer review to verify how robust and precise are such cheaper techniques.
Of course Schleiren optical methods have been embraced by the Fluid Mechanics community for a century. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: jmossman on 12/17/2015 04:20 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459046#msg1459046">Quote from: rfmwguy on 12/17/2015 03:40 PM</a>
Current would be OK, but the mag does not necessarily "lock" until it comes up to temp and stabilizes. This is why I proposed a spec an spike to show its lock mode rather than a current sampling. Anytime the RF peaks, it would show lock and it would be synchronized with the Schlieren video...simply overlaid on top and a screen recorder would make the combined video.
Sooo, Schlieren video runs on laptop, overlaid with a small spec analyzer display (also running in real time). Screen record video captures both in real time...make sense?
RF peaks would help determine if a "lock" correlates with any measured anomalies. However, I think having a "Magnetron On/Off" visual indicator would also be useful (using just "hum" from audio creates another unknown variable; if visual indicator and "hum" have a constant time offset, that would also be useful to know).
Being able to compare, whether a "lock" or "Magnetron On/Off" provides the stronger correlation with any measured anomalies, could be a hugely important data point.
EDIT: typo correction -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/17/2015 04:23 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459061#msg1459061">Quote from: rfmwguy on 12/17/2015 04:11 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459057#msg1459057">Quote from: Rodal on 12/17/2015 04:02 PM</a>
So Doc, can I count on you to take the next step? ::) I'll volunteer to get the gear and do the test IF you think its worthwhile.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459052#msg1459052">Quote from: rfmwguy on 12/17/2015 03:52 PM</a>OK, Doc, CEJ posted this on T5 and I forgot about it:
The author was in the Electrical Engineering Department Course Vi, and just concludes
http://forum.nasaspaceflight.com/index.php?topic=38577.msg1441327;topicseen#msg1441327
http://people.csail.mit.edu/tfxue/proj/fluidflow/
You're an MIT guy...give me your thoughts about their software!Quoteprovide promising evidence that refractive fluids can be analyzed in natural settings, which can make fluid flow measurement cheaper and more accessible
So, I trust that it is indeed "promising" which is what the author concludes.
The next step would be to verify whether these new algorithms and method have been embraced by the Fluid Mechanics community (in the Aeronautics and Astronautics Course XVI and Mechanical Engineering Course II departments at MIT) or by the academic fluid mechanics community in general. Everything in science and engineering is a question of independent duplication of experiments and peer review to verify how robust and precise are such cheaper techniques.
Of course Schleiren optical methods have been embraced by the Fluid Mechanics community for a century.
The solution involves a mathematical inversion.
The mathematical problem of inverting random refracted dynamic distortions is difficult, particularly when the objects in the field of view are moving as it is the case in fluid dynamics.
Whenever you invert a mathematical expression you encounter issues. Elementary examples are inversion of the square function (resulting in the square root which has two possible values for a given value of input). In this case the algorithms imply numerical inversion of matrices that may be ill-conditioned under a-priori unknown conditions
Can't give you a good answer as far as how robust this technique is, and can't volunteer the time to explore it. sorry. The author (who spent a considerable amount of time on it) writes that the technique is promising.
On the other hand if you go with Schlerein photography you would be using a technique that is known to be robust and does not have mathematical inversion issues.
It may be easier to use an infrared thermometer to measure the temperature of a turkey, but when cooking a Thanksgiving or Christmas dinner I rather use the old well-known technique of inserting a thermometer inside the turkey as it eliminates the problem of thermal conduction (the temperature inside the turkey is different from the surface temperature) and it eliminates the calibration of unknwon emissivity of the turkey exterior surface. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: lmbfan on 12/17/2015 05:13 PM -
Just FYI, there exists OpenFOAM, a computational fluid dynamics (CFD) suite, which appears to be fairly mature. I don't know enough about CFD to comment on whether or not OpenFOAM has the requisite solvers for modeling whichever thermal effects are present in/around a frustum.
http://openfoam.org/
https://en.wikipedia.org/wiki/OpenFOAM
Existing solvers:
http://openfoam.org/features/standard-solvers.php
I would be willing to create IGES, STEP, or STL (or a limited number of other, less common formats) files of frustums and/or experimental setups. I the software I use has the capability to "develop" solids for finite element analysis (FEA) and export it as ANSYS PREP7, and so therefore I may be able to help with that (if that is even necessary for CFD). Caveat - I have never "developed" a model for FEA analysis. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rq3 on 12/17/2015 05:34 PM -
Good ideas, but a spectrum spike of RF would show when the power was locked into a stable output...think this would do it. The Schlieren vid could have a small window on the same screen showing the spectrum...I would do a simple screen record of both videos simultaneously...
[/quote]
Shlieren systems are pretty straightforward if you decide to go ahead with this. Having built a few, a
couple of suggestions:
1) You'll need a reasonably collimated light source, like an old slide projector ;)
2) Rather than use the ubiquitous knife edges, try a pair of ronchi rulings. MUCH easier to align, larger test area, and immensely larger contrast ratio.
3) For a large test area, Fresnel lenses are cheap and useable. The image will suffer, but it will be viewable.
Also a few thoughts on thermal issues.
1) IF the frustum is reasonable rigid, hermetically sealed, and auto-tuned to the drive RF, it won't show any balloon effect from heating. The interior gas will pressurize as it gets hotter, but the gas MASS won't change. Pulling a vacuum on a waveguide (frustum) as others have suggested is begging for interior arcing.
2) If the frustum were placed inside a cylindrical "chimney" that travels with it, one would think that the heat plume would be identical with the "big end up", or the "big end down". For the same number of dissipated watts, the air flow should be identical regardless of frustum vertical orientation. The delta would be...thrust? -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: OnlyMe on 12/17/2015 05:44 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459099#msg1459099">Quote from: rq3 on 12/17/2015 05:34 PM</a>
....
Shlieren systems are pretty straightforward if you decide to go ahead with this. Having built a few, a
couple of suggestions:
1) You'll need a reasonably collimated light source, like an old slide projector ;)
2) Rather than use the ubiquitous knife edges, try a pair of ronchi rulings. MUCH easier to align, larger test area, and immensely larger contrast ratio.
3) For a large test area, Fresnel lenses are cheap and useable. The image will suffer, but it will be viewable.
Also a few thoughts on thermal issues.
1) IF the frustum is reasonable rigid, hermetically sealed, and auto-tuned to the drive RF, it won't show any balloon effect from heating. The interior gas will pressurize as it gets hotter, but the gas MASS won't change. Pulling a vacuum on a waveguide (frustum) as others have suggested is begging for interior arcing.
2) If the frustum were placed inside a cylindrical "chimney" that travels with it, one would think that the heat plume would be identical with the "big end up", or the "big end down". For the same number of dissipated watts, the air flow should be identical regardless of frustum vertical orientation. The delta would be...thrust?
Is the arcing mentioned at #1 above dependent on vacuum quality? Ultimately the thing would need to function in vacuum. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: robus on 12/17/2015 05:48 PM -
A small plea from the peanut gallery.
With all due respect, is it possible to limit discussion of tests and results to those that are actively participating in the forum? Given how vaguely the tests have been described by Shawyer and Yang it seems fruitless to continue to debate their results?
EW, Shell, rfmwguy, et al are all actively engaging (as they can) and thus answers about approaches, artifacts etc are readily available. But I, for one, don't see the point of reading the tea leaves of those other tests? Extraordinary results require extraordinary evidence and that is definitely in short supply from them. Why do we continue to debate their tests and results?
Am I missing something? -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rq3 on 12/17/2015 05:50 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459107#msg1459107">Quote from: OnlyMe on 12/17/2015 05:44 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459099#msg1459099">Quote from: rq3 on 12/17/2015 05:34 PM</a>
....
Shlieren systems are pretty straightforward if you decide to go ahead with this. Having built a few, a
couple of suggestions:
1) You'll need a reasonably collimated light source, like an old slide projector ;)
2) Rather than use the ubiquitous knife edges, try a pair of ronchi rulings. MUCH easier to align, larger test area, and immensely larger contrast ratio.
3) For a large test area, Fresnel lenses are cheap and useable. The image will suffer, but it will be viewable.
Also a few thoughts on thermal issues.
1) IF the frustum is reasonable rigid, hermetically sealed, and auto-tuned to the drive RF, it won't show any balloon effect from heating. The interior gas will pressurize as it gets hotter, but the gas MASS won't change. Pulling a vacuum on a waveguide (frustum) as others have suggested is begging for interior arcing.
2) If the frustum were placed inside a cylindrical "chimney" that travels with it, one would think that the heat plume would be identical with the "big end up", or the "big end down". For the same number of dissipated watts, the air flow should be identical regardless of frustum vertical orientation. The delta would be...thrust?
Is the arcing mentioned at #1 above dependent on vacuum quality? Ultimately the thing would need to function in vacuum.
If you're referring to a potential Emdrive is space, vacuum external to the wavequide is not relevant. Only vacuum within the wavequide counts. High power wavequide systems are often internally pressurized with dry gas. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: OnlyMe on 12/17/2015 05:54 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459114#msg1459114">Quote from: rq3 on 12/17/2015 05:50 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459107#msg1459107">Quote from: OnlyMe on 12/17/2015 05:44 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459099#msg1459099">Quote from: rq3 on 12/17/2015 05:34 PM</a>
....
Shlieren systems are pretty straightforward if you decide to go ahead with this. Having built a few, a
couple of suggestions:
1) You'll need a reasonably collimated light source, like an old slide projector ;)
2) Rather than use the ubiquitous knife edges, try a pair of ronchi rulings. MUCH easier to align, larger test area, and immensely larger contrast ratio.
3) For a large test area, Fresnel lenses are cheap and useable. The image will suffer, but it will be viewable.
Also a few thoughts on thermal issues.
1) IF the frustum is reasonable rigid, hermetically sealed, and auto-tuned to the drive RF, it won't show any balloon effect from heating. The interior gas will pressurize as it gets hotter, but the gas MASS won't change. Pulling a vacuum on a waveguide (frustum) as others have suggested is begging for interior arcing.
2) If the frustum were placed inside a cylindrical "chimney" that travels with it, one would think that the heat plume would be identical with the "big end up", or the "big end down". For the same number of dissipated watts, the air flow should be identical regardless of frustum vertical orientation. The delta would be...thrust?
Is the arcing mentioned at #1 above dependent on vacuum quality? Ultimately the thing would need to function in vacuum.
If you're referring to a potential Emdrive is space, vacuum external to the wavequide is not relevant. Only vacuum within the wavequide counts. High power wavequide systems are often internally pressurized with dry gas.
With a sealed frustum such as it appears Shell has, how difficult would it be to do just that then pressurize with a dry gas, or would simple pressurization be enough at this point.., and practical?
PS. Didn't Paul March earlier mention that due to leaks their frustum did equalize in vacuum? -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rq3 on 12/17/2015 05:59 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459115#msg1459115">Quote from: OnlyMe on 12/17/2015 05:54 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459114#msg1459114">Quote from: rq3 on 12/17/2015 05:50 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459107#msg1459107">Quote from: OnlyMe on 12/17/2015 05:44 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459099#msg1459099">Quote from: rq3 on 12/17/2015 05:34 PM</a>
....
Shlieren systems are pretty straightforward if you decide to go ahead with this. Having built a few, a
couple of suggestions:
1) You'll need a reasonably collimated light source, like an old slide projector ;)
2) Rather than use the ubiquitous knife edges, try a pair of ronchi rulings. MUCH easier to align, larger test area, and immensely larger contrast ratio.
3) For a large test area, Fresnel lenses are cheap and useable. The image will suffer, but it will be viewable.
Also a few thoughts on thermal issues.
1) IF the frustum is reasonable rigid, hermetically sealed, and auto-tuned to the drive RF, it won't show any balloon effect from heating. The interior gas will pressurize as it gets hotter, but the gas MASS won't change. Pulling a vacuum on a waveguide (frustum) as others have suggested is begging for interior arcing.
2) If the frustum were placed inside a cylindrical "chimney" that travels with it, one would think that the heat plume would be identical with the "big end up", or the "big end down". For the same number of dissipated watts, the air flow should be identical regardless of frustum vertical orientation. The delta would be...thrust?
Is the arcing mentioned at #1 above dependent on vacuum quality? Ultimately the thing would need to function in vacuum.
If you're referring to a potential Emdrive is space, vacuum external to the wavequide is not relevant. Only vacuum within the wavequide counts. High power wavequide systems are often internally pressurized with dry gas.
With a sealed frustum such as it appears Shell has, how difficult would it be to do just that then pressurize with a dry gas, or would simple pressurization be enough at this point.., and practical?
PS. Didn't Paul March earlier mention that due to leaks their frustum did equalize in vacuum?
From what I understand, Shell's frustum is not gas tight, and I think she has enough on her plate without introducing hermetic sealing and pressurization. But, given that it's Shell, you never know! -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: OnlyMe on 12/17/2015 06:04 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459116#msg1459116">Quote from: rq3 on 12/17/2015 05:59 PM</a>
....
From what I understand, Shell's frustum is not gas tight.
Shell, would have to confirm but,
From her pictures, it appears that once she has tuned, i.e. Adjusted with the micrometer, the bottom might also be sealable. The top is already sealed which would only leave sealing penetration points for waveguides, antennas and the venting line. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/17/2015 06:11 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459111#msg1459111">Quote from: robus on 12/17/2015 05:48 PM</a>
A small plea from the peanut gallery.
With all due respect, is it possible to limit discussion of tests and results to those that are actively participating in the forum? Given how vaguely the tests have been described by Shawyer and Yang it seems fruitless to continue to debate their results?
EW, Shell, rfmwguy, et al are all actively engaging (as they can) and thus answers about approaches, artifacts etc are readily available. But I, for one, don't see the point of reading the tea leaves of those other tests? Extraordinary results require extraordinary evidence and that is definitely in short supply from them. Why do we continue to debate their tests and results?
Am I missing something?
Yes, you are missing a lot if you limit your reading in this forum to just EW, RFMWGUY and Shell's testing/proposed testing.
The limited discussion that you propose has not been the purpose of these threads, starting from EM Drive thread 1 . For limited discussions of the EM Drive you can access other forums.
To see what you are missing by limiting the discussion, it is advisable to read threads 1 through 5. For a discussion of what this thread's discussion is about, please see the introduction to this thread:
http://forum.nasaspaceflight.com/index.php?topic=39004.msg1455930#msg1455930
There are myriads of examples that show the relevance of discussion of Yang's and Shawyer's tests, but just to mention a recent post, please refer to the recent discussion pointing out the fallacy of assuming that measured forces will scale linearly with input power:
http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458920#msg1458920
showing the strong nonlinearity of Yang's results. There is something to be learned from each published report.
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: robus on 12/17/2015 06:21 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459122#msg1459122">Quote from: Rodal on 12/17/2015 06:11 PM</a>
Yes, you are missing a lot if you limit discussion in this forum to just EW, RFMWGUY and Shell's testing/proposed testing.
The limited discussion that you propose has not been the purpose of these threads, starting from EM Drive thread 1 .
To see what you are missing by limiting the discussion, it is advisable to read threads 1 through 5, and the introduction to this thread:
http://forum.nasaspaceflight.com/index.php?topic=39004.msg1455930#msg1455930
No problem, I've been a long time lurker. It just seems like their tests and results have been argued to death and seem to generate a lot of heat and they're not participating to shed light on some of the murkier parts.
But I'm certainly in no position to argue against your judgement! Forgive the intrusion and please carry on :) -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: aero on 12/17/2015 06:28 PM -
Earlier there was a point made about buoyancy lift from the heated frustum. I did some calculations in an attempt to characterize buoyancy for Shell's EM drive configuration, (frustum, tuning cylinder, and two wave guides) since I do have the needed dimensional data in my meep model.
I calculate the volume to be less than 4.490367E-02 m3. Less than because the wave guides are cut at an angle by the frustum but I simply used the length of the long side. So there are two small wedges that are each counted twice.
So I found standard atmosphere data in the engineering toolbox and calculated the air density at constant volume and pressure using the Ideal gas law. I used the calculator here:
http://www.ajdesigner.com/idealgas/ideal_gas_law_density.php#ajscroll (http://www.ajdesigner.com/idealgas/ideal_gas_law_density.php#ajscroll)
I did this calculation at both standard temperature and 100 degrees C above standard. That is pretty hot, the temperature of boiling water. Oh, out of deference for Shells' high altitude in the mountains, I used 2000 meter data from the standard atmosphere.
With the above, I calculated buoyancy force = 0.1181471225 newtons, that's 118 mn and certainly not something that can be neglected. If someone is up to the task of checking my numbers, I'm sure it would be appreciated.
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/17/2015 06:29 PM -
Observe time dependent transient thermal convection from a cup of coffee. Transient pulsing and spiking bursts from the cup of coffee have nothing to do with the coffee being turned ON and OFF (the coffee cup in this video is not being turned on and off), but they are due to the fluid dynamics (periodic vortex shedding due to natural thermal convection) of the problem. You can imagine how complicated the problem would be if the cup of coffee would be on a burner that would be periodically turned ON and OFF as well, as the turning ON and OFF of the burner would interact with the transient fluid dynamics (vortex shedding) of natural convection.
Imagine the cup of coffee being RFMWGUY's magnetron sitting on top of his EM Drive !!!!
https://www.youtube.com/watch?v=Db4UOHC8WEc -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Space Ghost 1962 on 12/17/2015 06:37 PM -
A few notes about Schlieren systems, near/far field video analysis, and other means to monitor heating.
These systems all have different benefits/issues. The above mentioned optical systems are actually looking at refraction due to air density causing different refraction of transmitted light. So what you can get is a pattern of heating (likely corresponding to nodes impedance heating), but getting actual temps and integratable flux maps will take considerable calibration. Half (or more) the battle with getting such results are proving the accuracy of your measurement, so its not a "code" thing quite so much as a details/apparatus thing.
If what you are going for is total flux, calorimetry is likely what you are after. If point flux is the question, some kind of absorber on a low/non interacting support can allow a means to probe it.
Schlieren systems are scaled by cross sectional area with the optical system on a stiff optical bench with no vibration. It takes effort to collimate the system, damp out vibrations, and to have an ambient temperature stable room before test. High humidity affects measurement and dewing of the optics scatters the beam reducing contrast.
If you google "microwave", "heating", and "schlieren" you'll find some interesting papers. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: OnlyMe on 12/17/2015 06:38 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459127#msg1459127">Quote from: aero on 12/17/2015 06:28 PM</a>
Earlier there was a point made about buoyancy lift from the heated frustum. I did some calculations in an attempt to characterize buoyancy for Shell's EM drive configuration, (frustum, tuning cylinder, and two wave guides) since I do have the needed dimensional data in my meep model.
I calculate the volume to be less than 4.490367E-02 m3. Less than because the wave guides are cut at an angle by the frustum but I simply used the length of the long side. So there are two small wedges that are each counted twice.
So I found standard atmosphere data in the engineering toolbox and calculated the air density at constant volume and pressure using the Ideal gas law. I used the calculator here:
http://www.ajdesigner.com/idealgas/ideal_gas_law_density.php#ajscroll (http://www.ajdesigner.com/idealgas/ideal_gas_law_density.php#ajscroll)
I did this calculation at both standard temperature and 100 degrees C above standard. That is pretty hot, the temperature of boiling water. Oh, out of deference for Shells' high altitude in the mountains, I used 2000 meter data from the standard atmosphere.
With the above, I calculated buoyancy force = 0.1181471225 newtons, that's 118 mn and certainly not something that can be neglected. If someone is up to the task of checking my numbers, I'm sure it would be appreciated.
Now just need some actual heat data from Shell.
Rfmwguy, had the magnetron itself at around 150 degrees C, if I remember correctly, and much less the frustum itself, but that was a mesh frustum.
Once Shell has some actual data, it will start to get interesting for sure.
BTW Shell, since you moved inside, both room temperature and humidity, may be important. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: glennfish on 12/17/2015 06:39 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459127#msg1459127">Quote from: aero on 12/17/2015 06:28 PM</a>
With the above, I calculated buoyancy force = 0.1181471225 newtons, that's 118 mn and certainly not something that can be neglected. If someone is up to the task of checking my numbers, I'm sure it would be appreciated.
That's in the range of comparable calcs done previously for similar designs. Definitely a # to throw into the simulator I have.
While you're in a buoyant mood, can you look over HVAC calculators and see what the expected chimney airflow should look like for the same dimensions, depending on orientation, up, down, sideways?
The model I'm trying to work out assumes thermal effects in your order of magnitude that would differ slightly depending upon orientation.
These thermal effects are not bad. They are to be assumed present. What I'm trying to work out is a model that would show what kind of test protocol is required to statistically demonstrate thrust given that thrust may be a small percentage of thermal effects. i.e. it is possible to create a test protocol where the thrust is 10 mn and the boyancy is 118 mn, and you can at some point declare thrust is real. See attached simulator. If you can help produce initial estimated values and propose other error sources, that's double plus good. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/17/2015 06:42 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459084#msg1459084">Quote from: lmbfan on 12/17/2015 05:13 PM</a>
Just FYI, there exists OpenFOAM, a computational fluid dynamics (CFD) suite, which appears to be fairly mature. I don't know enough about CFD to comment on whether or not OpenFOAM has the requisite solvers for modeling whichever thermal effects are present in/around a frustum.
http://openfoam.org/
https://en.wikipedia.org/wiki/OpenFOAM
Existing solvers:
http://openfoam.org/features/standard-solvers.php
I would be willing to create IGES, STEP, or STL (or a limited number of other, less common formats) files of frustums and/or experimental setups. I the software I use has the capability to "develop" solids for finite element analysis (FEA) and export it as ANSYS PREP7, and so therefore I may be able to help with that (if that is even necessary for CFD). Caveat - I have never "developed" a model for FEA analysis.
Thank you, but CFD (computer fluid dynamics) analysis would, by comparison, make the Meep analysis pale by comparison. CFD analysis would entail running millions of cycles (hence much longer computational time), iteration sub-cycles (for nonlinear Navier Stokes equation solution), and dealing with numerical relaxation and numerical convergence settings (in addition to dealing with convergence of the mesh). Couple to that the analyst's time to analyze the input and output of these numerical solutions. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/17/2015 06:47 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459134#msg1459134">Quote from: glennfish on 12/17/2015 06:39 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459127#msg1459127">Quote from: aero on 12/17/2015 06:28 PM</a>
With the above, I calculated buoyancy force = 0.1181471225 newtons, that's 118 mn and certainly not something that can be neglected. If someone is up to the task of checking my numbers, I'm sure it would be appreciated.
That's in the range of comparable calcs done previously for similar designs. Definitely a # to throw into the simulator I have.
While you're in a buoyant mood, can you look over HVAC calculators and see what the expected chimney airflow should look like for the same dimensions, depending on orientation, up, down, sideways?
The model I'm trying to work out assumes thermal effects in your order of magnitude that would differ slightly depending upon orientation.
These thermal effects are not bad. They are to be assumed present. What I'm trying to work out is a model that would show what kind of test protocol is required to statistically demonstrate thrust given that thrust may be a small percentage of thermal effects. i.e. it is possible to create a test protocol where the thrust is 10 mn and the boyancy is 118 mn, and you can at some point declare thrust is real. See attached simulator. If you can help produce initial estimated values and propose other error sources, that's double plus good.
The bigger problem is the transient vortex shedding due to fluid dynamics, interacting with the ON/OFF timing of the magnetron (http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459128#msg1459128 ).
The lift force due to natural convection (with the magnetron constantly OFF) is time-dependent and not a steady constant.
The constant bouyancy calculations do not address the timing of the transient natural convection (not yet taken into account), and yet the statistical analysis is predicated on statistical analysis of the ON/OFF timing of the magnetron. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: aero on 12/17/2015 06:54 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459134#msg1459134">Quote from: glennfish on 12/17/2015 06:39 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459127#msg1459127">Quote from: aero on 12/17/2015 06:28 PM</a>
With the above, I calculated buoyancy force = 0.1181471225 newtons, that's 118 mn and certainly not something that can be neglected. If someone is up to the task of checking my numbers, I'm sure it would be appreciated.
That's in the range of comparable calcs done previously for similar designs. Definitely a # to throw into the simulator I have.
While you're in a buoyant mood, can you look over HVAC calculators and see what the expected chimney airflow should look like for the same dimensions, depending on orientation, up, down, sideways?
The model I'm trying to work out assumes thermal effects in your order of magnitude that would differ slightly depending upon orientation.
These thermal effects are not bad. They are to be assumed present. What I'm trying to work out is a model that would show what kind of test protocol is required to statistically demonstrate thrust given that thrust may be a small percentage of thermal effects. i.e. it is possible to create a test protocol where the thrust is 10 mn and the boyancy is 118 mn, and you can at some point declare thrust is real. See attached simulator. If you can help produce initial estimated values and propose other error sources, that's double plus good.
I found this:
http://www.engineeringtoolbox.com/natural-draught-ventilation-d_122.html (http://www.engineeringtoolbox.com/natural-draught-ventilation-d_122.html)
but I don't see how to apply it to this problem. We don't have a chimney, rather just a heat source with air flow entering from both the bottom and the 4 sides. More like the air flow around a suspended light bulb. Maybe I'll look further. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rfmwguy on 12/17/2015 07:05 PM -
Great discussions...yes, my mag temp idled between 150 and 170 degrees C depending on whether it was 30% or 50% power cycle respectively. 100% power for long duration was not measured on the original mag, but another pullout mag I tested got to 200 deg C quickly at 100% power. Thus confirmed my concern that getting a "matched" set of mags (one on each side of the balance beam) would be difficult...they're just not built precise enough.
Here's a simple test somebody can plug into some software...imagine a 4 inch square metallic box with 2 opposite sides open (vertical sides).
Heat the thing to 170 degrees C from a CENTRAL point within the box, conducting heat to the remaining walls via air convection and direct mechanical attachment.
Ambient air was 28 degrees C and humidity was about 56% in the tests I ran within a few days of each other.
The metal was galvanized steel. It is safe to assume 14 gauge steel or 0.0677 inches thick on 4 sides (5 & 6 are open). The weight was 750 mg (magnetron alone).
For those wishing to dig deeper, the non-hermetic box on top is about 3 inches tall and 3.75 inches square...made of the same material.
Below is a cropped image someone sent me of my mag, suggesting a heatsink idea.
These simple details should be enough to quantify the amount of vertical lift component (perhaps not turbulence).
Are we talking millinewtons? micronewtons? How similar is this to the 40 or so micronewtons of horizontal (torsional) Lorentz force? Remember vertical Lorentz force was not measured nor estimated in Mr Li's paper.
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: aero on 12/17/2015 07:15 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459137#msg1459137">Quote from: Rodal on 12/17/2015 06:47 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459134#msg1459134">Quote from: glennfish on 12/17/2015 06:39 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459127#msg1459127">Quote from: aero on 12/17/2015 06:28 PM</a>
With the above, I calculated buoyancy force = 0.1181471225 newtons, that's 118 mn and certainly not something that can be neglected. If someone is up to the task of checking my numbers, I'm sure it would be appreciated.
That's in the range of comparable calcs done previously for similar designs. Definitely a # to throw into the simulator I have.
While you're in a buoyant mood, can you look over HVAC calculators and see what the expected chimney airflow should look like for the same dimensions, depending on orientation, up, down, sideways?
The model I'm trying to work out assumes thermal effects in your order of magnitude that would differ slightly depending upon orientation.
These thermal effects are not bad. They are to be assumed present. What I'm trying to work out is a model that would show what kind of test protocol is required to statistically demonstrate thrust given that thrust may be a small percentage of thermal effects. i.e. it is possible to create a test protocol where the thrust is 10 mn and the boyancy is 118 mn, and you can at some point declare thrust is real. See attached simulator. If you can help produce initial estimated values and propose other error sources, that's double plus good.
The bigger problem is the transient vortex shedding due to fluid dynamics, interacting with the ON/OFF timing of the magnetron (http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459128#msg1459128 ).
The lift force due to natural convection is time-dependent and not a steady constant.
The constant bouyancy calculations do not address the timing of the transient natural convection (not yet taken into account), and yet the statistical analysis is predicated on statistical analysis of the ON/OFF timing of the magnetron.
The problem of buoyancy lift and natural convection lift (drag) forces are separable. Buoyancy is an effect from inside the EM drive while convection occurs outside the drive.
Under the conditions that I assume operation, buoyancy is a function of internal temperature only. Yes, temperature will change as the magnetron (heat source) is turned on and off. Characterizing the internal temperature of the drive as a function of time seems difficult to me, perhaps you have some ideas?
Natural convection is also a function of temperature, in this case, the temperature of the copper. Characterizing this temperature would be easier given the internal temperature as a function of time. The problem then arises, given the temperature of the copper as a function of time (power on/off) what do we do with it? I am not ready to solve the Navier-Stokes equations, I had enough of them while in college. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/17/2015 07:25 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459157#msg1459157">Quote from: aero on 12/17/2015 07:15 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459137#msg1459137">Quote from: Rodal on 12/17/2015 06:47 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459134#msg1459134">Quote from: glennfish on 12/17/2015 06:39 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459127#msg1459127">Quote from: aero on 12/17/2015 06:28 PM</a>
With the above, I calculated buoyancy force = 0.1181471225 newtons, that's 118 mn and certainly not something that can be neglected. If someone is up to the task of checking my numbers, I'm sure it would be appreciated.
That's in the range of comparable calcs done previously for similar designs. Definitely a # to throw into the simulator I have.
While you're in a buoyant mood, can you look over HVAC calculators and see what the expected chimney airflow should look like for the same dimensions, depending on orientation, up, down, sideways?
The model I'm trying to work out assumes thermal effects in your order of magnitude that would differ slightly depending upon orientation.
These thermal effects are not bad. They are to be assumed present. What I'm trying to work out is a model that would show what kind of test protocol is required to statistically demonstrate thrust given that thrust may be a small percentage of thermal effects. i.e. it is possible to create a test protocol where the thrust is 10 mn and the boyancy is 118 mn, and you can at some point declare thrust is real. See attached simulator. If you can help produce initial estimated values and propose other error sources, that's double plus good.
The bigger problem is the transient vortex shedding due to fluid dynamics, interacting with the ON/OFF timing of the magnetron (http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459128#msg1459128 ).
The lift force due to natural convection is time-dependent and not a steady constant.
The constant bouyancy calculations do not address the timing of the transient natural convection (not yet taken into account), and yet the statistical analysis is predicated on statistical analysis of the ON/OFF timing of the magnetron.
The problem of buoyancy lift and natural convection lift (drag) forces are separable. Buoyancy is an effect from inside the EM drive while convection occurs outside the drive.
Under the conditions that I assume operation, buoyancy is a function of internal temperature only. Yes, temperature will change as the magnetron (heat source) is turned on and off. Characterizing the internal temperature of the drive as a function of time seems difficult to me, perhaps you have some ideas?
Natural convection is also a function of temperature, in this case, the temperature of the copper. Characterizing this temperature would be easier given the internal temperature as a function of time. The problem then arises, given the temperature of the copper as a function of time (power on/off) what do we do with it? I am not ready to solve the Navier-Stokes equations, I had enough of them while in college.
If I understand you correctly you have been addressing only the buoyancy of the EM Drive cavity per se, as if it would be a hot air balloon.
But even a piece of burning paper will experience buoyancy due to the natural convection lift forces on it.
And in essence natural thermal convection is due to fluid dynamics where hotter air molecules experience buoyancy as compared to colder air molecules. (No need for a cavity to discuss buoyancy).
I am calling buoyancy the lift force due to natural thermal convection.
The magnetron on RFMWGUY's EM Drive was sitting on top of the EM Drive cavity. The EM Drive cavity had perforated mesh walls. The thermal camera showed that what got really hot was the magnetron sitting on top of the EM Drive and not the EM Drive cavity.
So I was referring to bouyancy of the magnetron. The magnetron is also a partially closed cavity, that experiences buoyancy effects.
(http://forum.nasaspaceflight.com/xindex.php,qaction=dlattach,3Btopic=39004.0,3Battach=1087271,3Bimage.pagespeed.ic.DCMo8RbjVq.webp)
Also the top plate of the EM Drive, under the magnetron, experiences a lift effect due to the natural convection flow. So I was also discussing buoyancy of that plate under the magnetron, as well.
These buoyancy forces (on the magnetron, and on the plate under the magnetron) are not constant (even with the magnetron constantly ON, or thereafter constantly OFF), but are a function of time, transient, due to vortex shedding and fluid dynamics transport of the natural convection of air molecules with different temperature.(http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459128#msg1459128) -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: glennfish on 12/17/2015 07:44 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459152#msg1459152">Quote from: rfmwguy on 12/17/2015 07:05 PM</a>
Are we talking millinewtons? micronewtons? How similar is this to the 40 or so micronewtons of horizontal (torsional) Lorentz force? Remember vertical Lorentz force was not measured nor estimated in Mr Li's paper.
Hundred(s) of milli newtons in the baseline frustums so far. Your mesh meshed things up since it was porous.
Here's where my brain is going and hopefully Aero or someone can plug in some more calcs for modeling.
Aero has provided a 1st approximation of the hot-air balloon effect for Shell's design. If her mag is rock solid and she flips orientation frequently, a 5-10mn thrust signal will emerge quickly. If it's in the micro N range, it will emerge very slowly. If the mag output is wobbly (new technical term), the wobblies could drown out any signal.
Statistically, a physics type likes a 6 sigma, separation between noise and signal.
For the DIY domain, I'd be ecstatic with a 3 sigma.
The issue is separating out thrust signals from thermal and other error sources. If the thrust is small, the number of required samples required becomes large. If the thrust is large, the number of samples required becomes small.
A rule of thumb for a 3 sigma finding. If the thrust is 10% of the other error sources, the number of samples required would be about 50. It's not a linear relationship, but a good mental model is, for every factor of 10 reduction in thrust as a percentage of other error source, the number of samples required to claim detection increases by a factor of 10.
If errors can be characterized, and their Standard Deviation minimized there's a reduction in the number of samples required.
I dream of a nice quiet stable magnetron, miminal airflow, stable ambient air temperature, and even if Lorenz is in the room hiding behind Elvis, he shouldn't matter much because there isn't going to be any noticeable shift in where the magnetic poles are during the runs.
Imagine it this way:
Assume thermal is 800 mn
Assume Lorenz is 5 mn
Assume other stuff is 10 mn
You have net junk thrust of 815 mn.
If your actual thrust is 5 mn and you can flip the frustum up or down and the only change is the direction of the thrust, then
If up you would see total thrust of 820 mn and down you would see 810 mn. If the thermal, Lorenz and stuff are rock solid, you'll see that 5 mn clearly and soon.
The key in my mind is very clean very stable unvarying sources of error. If their SDs are small, they simply go away from a statistics point of view. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Space Ghost 1962 on 12/17/2015 07:47 PM - Take a dead magnetron, core it out, stuff it with resistors or a electric dryer's heating element, and replace for the active one. If you dissipate the same heat, the same way, you've got a adequate "heat dummy" to do a difference with.
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/17/2015 07:50 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459173#msg1459173">Quote from: Space Ghost 1962 on 12/17/2015 07:47 PM</a>
Take a dead magnetron, core it out, stuff it with resistors or a electric dryer's heating element, and replace for the active one. If you dissipate the same heat, the same way, you've got a adequate "heat dummy" to do a difference with.
Or how about conducting two tests?
PURPOSE: Test whether the "effect" is purely thermal.
Vary the magnetron power vs. time for both cases so that the temperature of the magnetron is similar in both tests.
1) Magnetron RF exciting the EM Drive cavity (as already done by RFMWGUY)
2)Close the RF entrance into the EM Drive. Magnetron RF NOT exciting the EM Drive cavity.
_________
After that, another test;
3) Put one magnetron at one end of the balanced beam and the other magnetron at the other end of the balanced beam. One magnetron's RF is exciting the EM Drive cavity and the other one is not. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Space Ghost 1962 on 12/17/2015 07:57 PM -
Much more practical, but then what happens is that the magnetics of the magnetron are still in play, and you don't want to start "red herring" theories about the influence of them and the cavity.
By having a non microwave source, it's just about heat. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: aero on 12/17/2015 07:58 PM -
Quote
But even a piece of burning paper will experience buoyancy due to the natural convection lift forces on it.
No, that is not buoyancy. It is a matter of terminology. It is a lift force due to the natural convection currents created by the heat of burning paper. As I wrote above, buoyancy and convection are separable problems.
The magnetron itself will experience natural convection lift forces, but not buoyancy, because it is a sealed unit. It does not out-gas hence it's mass is constant. Perhaps there is a very small buoyancy due to the expansion of the metal of the magnetron with temperature but the expansion is small and the mass of the air displaced by that expansion is very, very small, I think negligible, when compared to the natural convection lift forces it experiences.
In my post, I was considering SeaShells' test rig and cavity. She has placed the magnetron at the pivot so that lift forces off the hot magnetron itself will be negated, be they buoyancy or natural convection lift forces.
I suggest we focus uniquely on a test set-up for our posts because the error sources are different for different test set-ups. Heat from the magnetron was definitely a factor with rfmwguy's test rig, but should not be a factor with Shells' rig. Similarly, buoyancy of the cavity will be a definite factor with Shells' rig but should not have been as much of a factor, if any, with rfmwguy's mesh cavity design. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/17/2015 07:59 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459180#msg1459180">Quote from: Space Ghost 1962 on 12/17/2015 07:57 PM</a>
Much more practical, but then what happens is that the magnetics of the magnetron are still in play, and you don't want to start "red herring" theories about the influence of them and the cavity.
By having a non microwave source, it's just about heat.
Good point. That is sort of what Yang reported in her last series of tests (she just heated her EM Drive).
She appears to not have reported anything else after that... (and it has been a long time) -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/17/2015 08:01 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459181#msg1459181">Quote from: aero on 12/17/2015 07:58 PM</a>Quote
But even a piece of burning paper will experience buoyancy due to the natural convection lift forces on it.
No, that is not buoyancy. It is a matter of terminology. It is a lift force due to the natural convection currents created by the heat of burning paper. As I wrote above, buoyancy and convection are separable problems.
The magnetron itself will experience natural convection lift forces, but not buoyancy, because it is a sealed unit. It does not out-gas hence it's mass is constant. Perhaps there is a very small buoyancy due to the expansion of the metal of the magnetron with temperature but the expansion is small and the mass of the air displaced by that expansion is very, very small, I think negligible, when compared to the natural convection lift forces it experiences.
In my post, I was considering SeaShells' test rig and cavity. She has placed the magnetron at the pivot so that lift forces off the hot magnetron itself will be negated, be they buoyancy or natural convection lift forces.
I suggest we focus uniquely on a test set-up for our posts because the error sources are different for different test set-ups. Heat from the magnetron was definitely a factor with rfmwguy's test rig, but should not be a factor with Shells' rig. Similarly, buoyancy of the cavity will be a definite factor with Shells' rig but should not have been as much of a factor, if any, with rfmwguy's mesh cavity design.
That may not be buoyancy according to you, but it is according to what I learnt,
Buoyancy is a force resulting from differences in fluid density
and also according to:
http://www.merriam-webster.com/dictionary/buoyancyQuotea : the tendency of a body to float or to rise when submerged in a fluid
b : the power of a fluid to exert an upward force on a body placed in it; also : the upward force exerted
https://en.wikipedia.org/wiki/BuoyancyQuoteIn science, buoyancy also known as upthrust) is an upward force exerted by a fluid that opposes the weight of an immersed object. In a column of fluid, pressure increases with depth as a result of the weight of the overlying fluid. Thus the pressure at the bottom of a column of fluid is greater than at the top of the column. Similarly, the pressure at the bottom of an object submerged in a fluid is greater than at the top of the object. This pressure difference results in a net upwards force on the object. The magnitude of that force exerted is proportional to that pressure difference, and (as explained by Archimedes' principle) is equivalent to the weight of the fluid that would otherwise occupy the volume of the object, i.e. the displaced fluid.
For this reason, an object whose density is greater than that of the fluid in which it is submerged tends to sink. If the object is either less dense than the liquid or is shaped appropriately (as in a boat), the force can keep the object afloat. This can occur only in a reference frame which either has a gravitational field or is accelerating due to a force other than gravity defining a "downward" direction (that is, a non-inertial reference frame). In a situation of fluid statics, the net upward buoyancy force is equal to the magnitude of the weight of fluid displaced by the body
https://en.wikipedia.org/wiki/Natural_convectionQuoteNatural convection is a mechanism, or type of heat transport, in which the fluid motion is not generated by any external source (like a pump, fan, suction device, etc.) but only by density differences in the fluid occurring due to temperature gradients. In natural convection, fluid surrounding a heat source receives heat, becomes less dense and rises. The surrounding, cooler fluid then moves to replace it. This cooler fluid is then heated and the process continues, forming a convection current; this process transfers heat energy from the bottom of the convection cell to top. The driving force for natural convection is buoyancy, a result of differences in fluid density.
////////////
The "body" experiencing buoyancy does not need to have metal walls or be a balloon, to experience buoyancy. It can be a hot gas molecule, or group of molecules. It can be a differential volume element in Continuum Mechanics. That is why the driving force for natural convection is buoyancy, a result of differences in fluid density. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rfmwguy on 12/17/2015 08:21 PM -
Whatever we work out, I'm at a point where DIY experimentation may not be worthwhile unless we can figure a way to characterize thermal dynamics.
From my perspective, I knew there was lift, what I was looking for was an interruption of it during mag on conditions. I believe I saw this clearly as either attenuation, reversal or a hold of the lift progression.
Remember, the thermal mass of the magnetron assembly does not permit instantaneous heating or cooling. If you look at the thermal videos, you see it is quite gradual...much slower than the instantaneous changes to the thermal lift profile I observed when mag switched between on and off, so my posit is that quick changes to a lift profile CANNOT be due to instantaneous heating or cooling at mag transition.
Where am I off base here? -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: aero on 12/17/2015 08:21 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459183#msg1459183">Quote from: Rodal on 12/17/2015 08:01 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459181#msg1459181">Quote from: aero on 12/17/2015 07:58 PM</a>Quote
But even a piece of burning paper will experience buoyancy due to the natural convection lift forces on it.
No, that is not buoyancy. It is a matter of terminology. It is a lift force due to the natural convection currents created by the heat of burning paper. As I wrote above, buoyancy and convection are separable problems.
The magnetron itself will experience natural convection lift forces, but not buoyancy, because it is a sealed unit. It does not out-gas hence it's mass is constant. Perhaps there is a very small buoyancy due to the expansion of the metal of the magnetron with temperature but the expansion is small and the mass of the air displaced by that expansion is very, very small, I think negligible, when compared to the natural convection lift forces it experiences.
In my post, I was considering SeaShells' test rig and cavity. She has placed the magnetron at the pivot so that lift forces off the hot magnetron itself will be negated, be they buoyancy or natural convection lift forces.
I suggest we focus uniquely on a test set-up for our posts because the error sources are different for different test set-ups. Heat from the magnetron was definitely a factor with rfmwguy's test rig, but should not be a factor with Shells' rig. Similarly, buoyancy of the cavity will be a definite factor with Shells' rig but should not have been as much of a factor, if any, with rfmwguy's mesh cavity design.
That may not be buoyancy according to you, but it is according to what I learnt, and also according to:
https://en.wikipedia.org/wiki/Buoyancy
From your reference, the applicable definition is "Buoyancy = weight of displaced fluid." In Shells' cavity, air is displaced by the added heat causing lower density as the pressure is equalized by displaced air flow out the relief tube.QuoteQuoteIn science, buoyancy also known as upthrust) is an upward force exerted by a fluid that opposes the weight of an immersed object. In a column of fluid, pressure increases with depth as a result of the weight of the overlying fluid. Thus the pressure at the bottom of a column of fluid is greater than at the top of the column. Similarly, the pressure at the bottom of an object submerged in a fluid is greater than at the top of the object. This pressure difference results in a net upwards force on the object. The magnitude of that force exerted is proportional to that pressure difference, and (as explained by Archimedes' principle) is equivalent to the weight of the fluid that would otherwise occupy the volume of the object, i.e. the displaced fluid.
For this reason, an object whose density is greater than that of the fluid in which it is submerged tends to sink. If the object is either less dense than the liquid or is shaped appropriately (as in a boat), the force can keep the object afloat. This can occur only in a reference frame which either has a gravitational field or is accelerating due to a force other than gravity defining a "downward" direction (that is, a non-inertial reference frame). In a situation of fluid statics, the net upward buoyancy force is equal to the magnitude of the weight of fluid displaced by the body
https://en.wikipedia.org/wiki/Natural_convectionQuoteNatural convection is a mechanism, or type of heat transport, in which the fluid motion is not generated by any external source (like a pump, fan, suction device, etc.) but only by density differences in the fluid occurring due to temperature gradients. In natural convection, fluid surrounding a heat source receives heat, becomes less dense and rises. The surrounding, cooler fluid then moves to replace it. This cooler fluid is then heated and the process continues, forming a convection current; this process transfers heat energy from the bottom of the convection cell to top. The driving force for natural convection is buoyancy, a result of differences in fluid density.
The driving force is buoyancy of the warm air, due to its lower density. That is the cause of natural convection. From your reference quoted above. "In natural convection, fluid surrounding a heat source receives heat, becomes less dense and rises."
As I wrote above, it is a misunderstanding of the terminology. Attempting to model buoyancy forces using the equations for natural convection, or alternatively, attempting to model natural convection using equations for buoyancy forces is a lost cause. Neither is applicable to the other. They are separable issues. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/17/2015 08:34 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459191#msg1459191">Quote from: rfmwguy on 12/17/2015 08:21 PM</a>
Whatever we work out, I'm at a point where DIY experimentation may not be worthwhile unless we can figure a way to characterize thermal dynamics.
From my perspective, I knew there was lift, what I was looking for was an interruption of it during mag on conditions. I believe I saw this clearly as either attenuation, reversal or a hold of the lift progression.
Remember, the thermal mass of the magnetron assembly does not permit instantaneous heating or cooling. If you look at the thermal videos, you see it is quite gradual...much slower than the instantaneous changes to the thermal lift profile I observed when mag switched between on and off, so my posit is that quick changes to a lift profile CANNOT be due to instantaneous heating or cooling at mag transition.
Where am I off base here?
Your experiments do NOT show that effect consistently with every ON and OFF turning of the magnetron: the thermal lift profile observed when magnetron was switched on and off was not the same through time You had to appeal to statistics to arrive at a conclusion. The statistics are based on a small sample population hence questionable from a statistical viewpoint.
Physically, the effect you observed may be due to transient thermal natural convection. There was no analysis of the transient thermal natural convection effect in your experiment (due to the hot magnetron sitting on top of the upper plate of the EM Drive). Transient thermal natural convection effects will result in statistical-looking effects like the one you measured. If the sample population was representative of the true statistical population (which was NOT shown), the statistical test may be only showing the effect of transient thermal natural convection effects.
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/17/2015 08:46 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459191#msg1459191">Quote from: rfmwguy on 12/17/2015 08:21 PM</a>
Whatever we work out, I'm at a point where DIY experimentation may not be worthwhile unless we can figure a way to characterize thermal dynamics.
From my perspective, I knew there was lift, what I was looking for was an interruption of it during mag on conditions. I believe I saw this clearly as either attenuation, reversal or a hold of the lift progression.
Remember, the thermal mass of the magnetron assembly does not permit instantaneous heating or cooling. If you look at the thermal videos, you see it is quite gradual...much slower than the instantaneous changes to the thermal lift profile I observed when mag switched between on and off, so my posit is that quick changes to a lift profile CANNOT be due to instantaneous heating or cooling at mag transition.
Where am I off base here?
To be "on base" you would have to follow with these tests:
http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459176#msg1459176
http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459173#msg1459173
to show that there is an anomalous force in your tests that cannot be explained by transient thermal convection effects. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rfmwguy on 12/17/2015 08:54 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459207#msg1459207">Quote from: Rodal on 12/17/2015 08:34 PM</a>
Doc, while it was not consistent each time, its easy to see from the video of the mag spectrum that its own rf stability is more likely the cause rather than a transient thermal natural convection effect, which I am trying to understand what you mean here.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459191#msg1459191">Quote from: rfmwguy on 12/17/2015 08:21 PM</a>Whatever we work out, I'm at a point where DIY experimentation may not be worthwhile unless we can figure a way to characterize thermal dynamics.
From my perspective, I knew there was lift, what I was looking for was an interruption of it during mag on conditions. I believe I saw this clearly as either attenuation, reversal or a hold of the lift progression.
Remember, the thermal mass of the magnetron assembly does not permit instantaneous heating or cooling. If you look at the thermal videos, you see it is quite gradual...much slower than the instantaneous changes to the thermal lift profile I observed when mag switched between on and off, so my posit is that quick changes to a lift profile CANNOT be due to instantaneous heating or cooling at mag transition.
Where am I off base here?
Your experiments do NOT show that effect consistently with every ON and OFF turning of the magnetron: the thermal lift profile observed when magnetron was switched on and off was not the same through time You had to appeal to statistics to arrive at a conclusion. The statistics are based on a small sample population hence questionable from a statistical viewpoint.
Physically, the effect you observed may be due to transient thermal natural convection. There was no analysis of the transient thermal natural convectin effect in your experiment (due to the hot magnetron sitting on top of the upper plate of the EM Drive). Transient thermal natural convection effects will result in statistical-looking effects like the one you measured.
Remember, the displacement was downward (against lift), not upwards during mag-on at a higher occurance over the 2000 or so data points. Your suggestion seems to imply vertical (upward) jetting which I cannot visualize in my test. The rising plume of thermals should (if I understand basic fluid dynamics) impose an upwards lift, not a downward force.
Is there something you can point me to help me understand an opposite effect of what I am thinking? i.e. a rising, thermal plume causing a downwards force? -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: glennfish on 12/17/2015 08:55 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459191#msg1459191">Quote from: rfmwguy on 12/17/2015 08:21 PM</a>
Whatever we work out, I'm at a point where DIY experimentation may not be worthwhile unless we can figure a way to characterize thermal dynamics.
From my perspective, I knew there was lift, what I was looking for was an interruption of it during mag on conditions. I believe I saw this clearly as either attenuation, reversal or a hold of the lift progression.
Remember, the thermal mass of the magnetron assembly does not permit instantaneous heating or cooling. If you look at the thermal videos, you see it is quite gradual...much slower than the instantaneous changes to the thermal lift profile I observed when mag switched between on and off, so my posit is that quick changes to a lift profile CANNOT be due to instantaneous heating or cooling at mag transition.
Where am I off base here?
To me it's an issue of, given a frustum mag orientation, we need to develop a model of the thrust behavior which includes all the balloons, lorenz forces, air flows, and maybe a modicum of EMDrive. Get enough data to derive a function that looks like:
displacementaka thrust = function(power on time)orientation
Wrap some standard deviations around that for orientation up and orientation down
It's a numbers game statistically. Run enough samples until either the standard deviations no longer overlap, or until you realize you don't have time to do enough runs.
To me, it doesn't matter how many confounding error sources there are, as long as they are always there and consistent. Thrust with orientation up will be the same as thrust with orientation down if and only if there is no thrust, all other things being equal. If there is thrust within the limits of your measurement devices, it will emerge statistically at some point. If there isn't, or it isn't within the limits of your measurement devices, it will not.
The debate then would become, were all other things equal. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: lmbfan on 12/17/2015 09:05 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459152#msg1459152">Quote from: rfmwguy on 12/17/2015 07:05 PM</a>
Great discussions...yes, my mag temp idled between 150 and 170 degrees C depending on whether it was 30% or 50% power cycle respectively. 100% power for long duration was not measured on the original mag, but another pullout mag I tested got to 200 deg C quickly at 100% power. Thus confirmed my concern that getting a "matched" set of mags (one on each side of the balance beam) would be difficult...they're just not built precise enough.
Here's a simple test somebody can plug into some software...imagine a 4 inch square metallic box with 2 opposite sides open (vertical sides).
Heat the thing to 170 degrees C from a CENTRAL point within the box, conducting heat to the remaining walls via air convection and direct mechanical attachment.
Ambient air was 28 degrees C and humidity was about 56% in the tests I ran within a few days of each other.
The metal was galvanized steel. It is safe to assume 14 gauge steel or 0.0677 inches thick on 4 sides (5 & 6 are open). The weight was 750 mg (magnetron alone).
For those wishing to dig deeper, the non-hermetic box on top is about 3 inches tall and 3.75 inches square...made of the same material.
Below is a cropped image someone sent me of my mag, suggesting a heatsink idea.
These simple details should be enough to quantify the amount of vertical lift component (perhaps not turbulence).
Are we talking millinewtons? micronewtons? How similar is this to the 40 or so micronewtons of horizontal (torsional) Lorentz force? Remember vertical Lorentz force was not measured nor estimated in Mr Li's paper.
Please find attached a simple model of the above in the common IGES format. I'd think that adding some type of thermal mass to the center of the housing would be advisable, seeing as how there is a lot more geometry here than the outer housing. This is NOT a simulation of any kind, this is just a model I make available to anyone who has the knowhow to do a simulation. If I have some spare time later, I might be able to run an extremely simple thermal analysis, but as I have never attempted one before, I would not know if it was set up properly.
Added: 2" hole on the bottom of the top piece, .5"X1.5" hole on the side of the top piece for connector.
If these are harmful to the model, I can remove them easily, I can also add any other simple features. I can also export the model in STEP or STL format if necessary. Rename "mag_asm.txt" to "mag_asm.igs" (IGES files are plain text). -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SeeShells on 12/17/2015 09:09 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459207#msg1459207">Quote from: Rodal on 12/17/2015 08:34 PM</a>
Throwing this out there for discussion.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459191#msg1459191">Quote from: rfmwguy on 12/17/2015 08:21 PM</a>Whatever we work out, I'm at a point where DIY experimentation may not be worthwhile unless we can figure a way to characterize thermal dynamics.
From my perspective, I knew there was lift, what I was looking for was an interruption of it during mag on conditions. I believe I saw this clearly as either attenuation, reversal or a hold of the lift progression.
Remember, the thermal mass of the magnetron assembly does not permit instantaneous heating or cooling. If you look at the thermal videos, you see it is quite gradual...much slower than the instantaneous changes to the thermal lift profile I observed when mag switched between on and off, so my posit is that quick changes to a lift profile CANNOT be due to instantaneous heating or cooling at mag transition.
Where am I off base here?
Your experiments do NOT show that effect consistently with every ON and OFF turning of the magnetron: the thermal lift profile observed when magnetron was switched on and off was not the same through time You had to appeal to statistics to arrive at a conclusion. The statistics are based on a small sample population hence questionable from a statistical viewpoint.
Physically, the effect you observed may be due to transient thermal natural convection. There was no analysis of the transient thermal natural convection effect in your experiment (due to the hot magnetron sitting on top of the upper plate of the EM Drive). Transient thermal natural convection effects will result in statistical-looking effects like the one you measured. If the sample population was representative of the true statistical population (which was NOT shown), the statistical test may be only showing the effect of transient thermal natural convection effects.
rfmwguy I'd consider a heat lamp ~250w http://www.acehardware.com/product/index.jsp?productId=35077376
Mount it pointing down a couple of inches from where your magnetron would be facing the frustum endplate. Monitor the thermal rise in temp, and the lift over time with your digital distance hardware and plot it.
I'm down for a few days... Dr's orders so I'll not be posting much but HAD to reply to this.
Shell -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/17/2015 09:11 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459215#msg1459215">Quote from: rfmwguy on 12/17/2015 08:54 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459207#msg1459207">Quote from: Rodal on 12/17/2015 08:34 PM</a>
Doc, while it was not consistent each time, its easy to see from the video of the mag spectrum that its own rf stability is more likely the cause rather than a transient thermal natural convection effect, which I am trying to understand what you mean here.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459191#msg1459191">Quote from: rfmwguy on 12/17/2015 08:21 PM</a>Whatever we work out, I'm at a point where DIY experimentation may not be worthwhile unless we can figure a way to characterize thermal dynamics.
From my perspective, I knew there was lift, what I was looking for was an interruption of it during mag on conditions. I believe I saw this clearly as either attenuation, reversal or a hold of the lift progression.
Remember, the thermal mass of the magnetron assembly does not permit instantaneous heating or cooling. If you look at the thermal videos, you see it is quite gradual...much slower than the instantaneous changes to the thermal lift profile I observed when mag switched between on and off, so my posit is that quick changes to a lift profile CANNOT be due to instantaneous heating or cooling at mag transition.
Where am I off base here?
Your experiments do NOT show that effect consistently with every ON and OFF turning of the magnetron: the thermal lift profile observed when magnetron was switched on and off was not the same through time You had to appeal to statistics to arrive at a conclusion. The statistics are based on a small sample population hence questionable from a statistical viewpoint.
Physically, the effect you observed may be due to transient thermal natural convection. There was no analysis of the transient thermal natural convectin effect in your experiment (due to the hot magnetron sitting on top of the upper plate of the EM Drive). Transient thermal natural convection effects will result in statistical-looking effects like the one you measured.
Remember, the displacement was downward (against lift), not upwards during mag-on at a higher occurance over the 2000 or so data points. Your suggestion seems to imply vertical (upward) jetting which I cannot visualize in my test. The rising plume of thermals should (if I understand basic fluid dynamics) impose an upwards lift, not a downward force.
Is there something you can point me to help me understand an opposite effect of what I am thinking? i.e. a rising, thermal plume causing a downwards force?
Take a gander at this: http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459128#msg1459128
There is no constant, rising plume of thermal lift from a hot cup of coffee. There is no constant, rising plume of thermal lift from your test either. It is time dependent, due to vortex shedding fluid dynamics effects.
When you turn the magnetron on and off you superimpose additional transient thermal convection effects that disturb a damped balance that was previously subject to transient thermal convection. One cannot account for the additional effects of turning the magnetron ON and OFF, simply linearly, because the problem you are dealing with (thermal convection) is nonlinear. The effect of turning the magnetron ON may be counterintuitive, if one does not visualize what is happening to the air flow when you are turning the magnetron ON.
I find it noteworthy that the effect you are showing is statistical: it is NOT present every time the magnetron goes on. This statistical nature leads to me to think that it is due to natural convection air flow.
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/17/2015 09:48 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459215#msg1459215">Quote from: rfmwguy on 12/17/2015 08:54 PM</a>
I answered your question. Now a QUESTION for you :) :<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459207#msg1459207">Quote from: Rodal on 12/17/2015 08:34 PM</a>
Doc, while it was not consistent each time, its easy to see from the video of the mag spectrum that its own rf stability is more likely the cause rather than a transient thermal natural convection effect, which I am trying to understand what you mean here.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459191#msg1459191">Quote from: rfmwguy on 12/17/2015 08:21 PM</a>Whatever we work out, I'm at a point where DIY experimentation may not be worthwhile unless we can figure a way to characterize thermal dynamics.
From my perspective, I knew there was lift, what I was looking for was an interruption of it during mag on conditions. I believe I saw this clearly as either attenuation, reversal or a hold of the lift progression.
Remember, the thermal mass of the magnetron assembly does not permit instantaneous heating or cooling. If you look at the thermal videos, you see it is quite gradual...much slower than the instantaneous changes to the thermal lift profile I observed when mag switched between on and off, so my posit is that quick changes to a lift profile CANNOT be due to instantaneous heating or cooling at mag transition.
Where am I off base here?
Your experiments do NOT show that effect consistently with every ON and OFF turning of the magnetron: the thermal lift profile observed when magnetron was switched on and off was not the same through time You had to appeal to statistics to arrive at a conclusion. The statistics are based on a small sample population hence questionable from a statistical viewpoint.
Physically, the effect you observed may be due to transient thermal natural convection. There was no analysis of the transient thermal natural convectin effect in your experiment (due to the hot magnetron sitting on top of the upper plate of the EM Drive). Transient thermal natural convection effects will result in statistical-looking effects like the one you measured.
Remember, the displacement was downward (against lift), not upwards during mag-on at a higher occurance over the 2000 or so data points. Your suggestion seems to imply vertical (upward) jetting which I cannot visualize in my test. The rising plume of thermals should (if I understand basic fluid dynamics) impose an upwards lift, not a downward force.
Is there something you can point me to help me understand an opposite effect of what I am thinking? i.e. a rising, thermal plume causing a downwards force?
Why is yours the first (and only) EM Drive test I know of that has to appeal to statistics to show an EM Drive force, under the same identical test configuration, during the same overall test?
Am I correct that all the other tests (by Shawyer, Yang, NASA, Tajmar, Berca, etc.) claim that the EM Drive thrust in their tests is a reproducible effect, every time that the RF is turned on?
What (in your opinion) is responsible for the statistical nature of your tests, such that sometimes turning the magnetron ON had no measurable effect?
(my answer is that this is due to transient thermal convection effects on the teeter totter balance)
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Flyby on 12/17/2015 10:29 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458920#msg1458920">Quote from: Rodal on 12/17/2015 11:49 AM</a>
.....
A few weeks ago, I used those Yang plots to determine the efficiency of her EMdrive while the input power increased.
2) The experimental results of Prof. Yang showed strong nonlinearity between the measured force and the input power (see attached chart). Prof. Yang's experiments show diminishing returns (actually slight decrease in measured forces for input power exceeding 300 Watts and general flat response) for increasing input power.
Hence it does not follow that the thermal artifacts will scale linearly in experiments conducted at much higher input power. On the contrary, Prof. Yang's experimental results show strong nonlinearity, with the touted "EM Drive" force dependence on input power effectively dissappearing after about 300 watts, the dependence looks practically flat at input powers greater than 300 W. The nonlinearity of the "force" vs. input power experimental relation of Prof. Yang has not yet been scientifically modeled hence its nature can only be speculated until a verifiable model is demonstrated.
This shows that if anything, experiments conducted at ambient conditions with low power may be highly misleading and NOT linearly scalable to higher powers, just as it would be highly misleading to conflate the flight of an insect with the flight of an airplane (the aerodynamics are completely different at very low Reynolds numbers).(The range of Reynolds number in insect flight is about 10 to 10^4, which lies in between the two limits that are convenient for theories that try to simplify the nonlinearity of Navier Stokes fluid dynamics: inviscid steady flows around an airplane's airfoil and Stokes flow experienced by a swimming bacterium. For this reason, this intermediate Reynolds number range used by insects in their flight is not as well understood as the high Reynolds number regime for airplanes. )
What I did is to bring all generated forces back to 1kW of power to get an idea how her frustum performed while she gradually increased the power...
It didn't show a straight linear relation, but a steep decline in efficiency at first, then leveled out for a long period and at the end showed improvement again, which might hint that a drastic increase in power "might" yield better then expected results.
I find it puzzling to why it stayed almost completely level from around 800W up to 2200W...
The performance degrading from 300W to 700W is probably due to thermal effects?
added:
to eliminate yang's individual test variations I averaged the force results (blue line) to get a single value. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: OnlyMe on 12/17/2015 10:31 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459246#msg1459246">Quote from: Rodal on 12/17/2015 09:48 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459215#msg1459215">Quote from: rfmwguy on 12/17/2015 08:54 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459207#msg1459207">Quote from: Rodal on 12/17/2015 08:34 PM</a>
Doc, while it was not consistent each time, its easy to see from the video of the mag spectrum that its own rf stability is more likely the cause rather than a transient thermal natural convection effect, which I am trying to understand what you mean here.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459191#msg1459191">Quote from: rfmwguy on 12/17/2015 08:21 PM</a>Whatever we work out, I'm at a point where DIY experimentation may not be worthwhile unless we can figure a way to characterize thermal dynamics.
From my perspective, I knew there was lift, what I was looking for was an interruption of it during mag on conditions. I believe I saw this clearly as either attenuation, reversal or a hold of the lift progression.
Remember, the thermal mass of the magnetron assembly does not permit instantaneous heating or cooling. If you look at the thermal videos, you see it is quite gradual...much slower than the instantaneous changes to the thermal lift profile I observed when mag switched between on and off, so my posit is that quick changes to a lift profile CANNOT be due to instantaneous heating or cooling at mag transition.
Where am I off base here?
Your experiments do NOT show that effect consistently with every ON and OFF turning of the magnetron: the thermal lift profile observed when magnetron was switched on and off was not the same through time You had to appeal to statistics to arrive at a conclusion. The statistics are based on a small sample population hence questionable from a statistical viewpoint.
Physically, the effect you observed may be due to transient thermal natural convection. There was no analysis of the transient thermal natural convectin effect in your experiment (due to the hot magnetron sitting on top of the upper plate of the EM Drive). Transient thermal natural convection effects will result in statistical-looking effects like the one you measured.
Remember, the displacement was downward (against lift), not upwards during mag-on at a higher occurance over the 2000 or so data points. Your suggestion seems to imply vertical (upward) jetting which I cannot visualize in my test. The rising plume of thermals should (if I understand basic fluid dynamics) impose an upwards lift, not a downward force.
Is there something you can point me to help me understand an opposite effect of what I am thinking? i.e. a rising, thermal plume causing a downwards force?
A QUESTION for you:
Why is yours the first (and only) EM Drive test I know of that has to appeal to statistics to show an EM Drive force?
Am I correct that all the other tests (by Shawyer, Yang, NASA, Tajmar, Berca, etc.) claim that the EM Drive thrust in their tests is a reproducible effect, every time that the RF is turned on?
What (in your opinion) is responsible for the statistical nature of your tests, such that sometimes turning the magnetron ON had no measurable effect?
The EMDrive wiki says Berca had at least two inconclusive tests before a successful test. So not every time.
Shawyer, I am sure did not always get results he published and has been at it for how many decades?
Yang had a lab and working group and it seems funding, but it doesn't really say how many failures might have Preceded the success she claims.
Eagleworks also played around a bit. How many frustums? Seems Paul implied more than one which would seem to suggest not all were successful.
Why did rfmwguy's experiment fall on the low side of repeatable results? A very low Q? To start and novel approach with the mesh.., and did he not mention that when he added the tuning rings the resonance or Q improved by, what double? But I don't think he reran the tests at that point.
Tajmar, for one seems inconclusive based on design and was not looking for thrust. "Direct Thrust Measurements of an EM Drive and Evaluation of Possible Side-Effects". I could very well be mistaken but I understood his purpose was to try and find ways to address thermal and systemic issues... Hence putting the frustum in an insulated boxe filled with fiber glass to reduce or eliminate thermally induced convection noise.
I believe you are attempting to hold DIY low budget projects to standards even some labs would have difficulty with.
Was what rfmwguy saw thrust that cannot be accounted for as thermal, impossible to say from where either of us sit.., without independently retesting his whole system. As I have said a few times to get out of the noise I believe the DIY experiments are going to need at least double digit mN of thrust... I thought that is essentially where rfmwguy said he was aiming for in 2016. Low double digits.
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/17/2015 10:49 PM -
Berca's previous null tests had a different configuration, and experimental setup.
Berca's tests with identical test configuration were reproducible.
Paul March already addressed in previous threads that he had no test (with a dielectric, and mode shape TM212) resulting in no thrust. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: oliverio on 12/17/2015 11:12 PM - Might I ask why no one has suggested just putting the frustrum in a sealed box, then heating the box to very high heats. If my understanding is correct, the sorts of flow dynamics discussed here should be gone in a closed system heated to 200 degrees Celsius. There is no way the frustrum could heat the air enough (relatively speaking) to cause significant thermal lift.
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Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SeeShells on 12/17/2015 11:36 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459287#msg1459287">Quote from: Rodal on 12/17/2015 10:49 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459278#msg1459278">Quote from: OnlyMe on 12/17/2015 10:31 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459246#msg1459246">Quote from: Rodal on 12/17/2015 09:48 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459215#msg1459215">Quote from: rfmwguy on 12/17/2015 08:54 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459207#msg1459207">Quote from: Rodal on 12/17/2015 08:34 PM</a>
Doc, while it was not consistent each time, its easy to see from the video of the mag spectrum that its own rf stability is more likely the cause rather than a transient thermal natural convection effect, which I am trying to understand what you mean here.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459191#msg1459191">Quote from: rfmwguy on 12/17/2015 08:21 PM</a>Whatever we work out, I'm at a point where DIY experimentation may not be worthwhile unless we can figure a way to characterize thermal dynamics.
From my perspective, I knew there was lift, what I was looking for was an interruption of it during mag on conditions. I believe I saw this clearly as either attenuation, reversal or a hold of the lift progression.
Remember, the thermal mass of the magnetron assembly does not permit instantaneous heating or cooling. If you look at the thermal videos, you see it is quite gradual...much slower than the instantaneous changes to the thermal lift profile I observed when mag switched between on and off, so my posit is that quick changes to a lift profile CANNOT be due to instantaneous heating or cooling at mag transition.
Where am I off base here?
Your experiments do NOT show that effect consistently with every ON and OFF turning of the magnetron: the thermal lift profile observed when magnetron was switched on and off was not the same through time You had to appeal to statistics to arrive at a conclusion. The statistics are based on a small sample population hence questionable from a statistical viewpoint.
Physically, the effect you observed may be due to transient thermal natural convection. There was no analysis of the transient thermal natural convectin effect in your experiment (due to the hot magnetron sitting on top of the upper plate of the EM Drive). Transient thermal natural convection effects will result in statistical-looking effects like the one you measured.
Remember, the displacement was downward (against lift), not upwards during mag-on at a higher occurance over the 2000 or so data points. Your suggestion seems to imply vertical (upward) jetting which I cannot visualize in my test. The rising plume of thermals should (if I understand basic fluid dynamics) impose an upwards lift, not a downward force.
Is there something you can point me to help me understand an opposite effect of what I am thinking? i.e. a rising, thermal plume causing a downwards force?
A QUESTION for you:
Why is yours the first (and only) EM Drive test I know of that has to appeal to statistics to show an EM Drive force?
Am I correct that all the other tests (by Shawyer, Yang, NASA, Tajmar, Berca, etc.) claim that the EM Drive thrust in their tests is a reproducible effect, every time that the RF is turned on?
What (in your opinion) is responsible for the statistical nature of your tests, such that sometimes turning the magnetron ON had no measurable effect?
The EMDrive wiki says Berca had at least two inconclusive tests before a successful test. So not every time.
Shawyer, I am sure did not always get results he published and has been at it for how many decades?
Yang had a lab and working group and it seems funding, but it doesn't really say how many failures might have Preceded the success she claims.
Eagleworks also played around a bit. How many frustums? Seems Paul implied more than one which would seem to suggest not all were successful.
Why did rfmwguy's experiment fall on the low side of repeatable results? A very low Q? To start and novel approach with the mesh.., and did he not mention that when he added the tuning rings the resonance or Q improved by, what double? But I don't think he reran the tests at that point.
Tajmar, for one seems inconclusive based on design and was not looking for thrust. "Direct Thrust Measurements of an EM Drive and Evaluation of Possible Side-Effects". I could very well be mistaken but I understood his purpose was to try and find ways to address thermal and systemic issues... Hence putting the frustum in an insulated boxe filled with fiber glass to reduce or eliminate thermally induced convection noise.
I believe you are attempting to hold DIY low budget projects to standards even some labs would have difficulty with.
Was what rfmwguy saw thrust that cannot be accounted for as thermal, impossible to say from where either of us sit.., without independently retesting his whole system. As I have said a few times to get out of the noise I believe the DIY experiments are going to need at least double digit mN of thrust... I thought that is essentially where rfmwguy said he was aiming for in 2016. Low double digits.
Berca's previous null tests had a different configuration, and experimental setup.
Berca's tests with identical test configuration were reproducible.
Paul March already addressed in previous threads that he had no test (with a dielectric, and mode shape TM212) resulting in no thrust.
What we are discussing about RFMGUY's test is not that he had different results with different tests. What we are discussing is that he measured different results during the same identical test, when turning the magnetron on at different times.
Paul March has many tests were he shows the experimental measurement vs time. There is not a single such trace showing Paul March's results during the same test where he would get no experimental force when turning the RF on. The issue with NASA's test was one of drift of the baseline, but never one of showing no force when the RF was turned on. NASA's measurements showed that an experimental force trace measurement every time that the RF was turned on during the same test.
I would propose that due to the nature of rfmwguy's magnetron setup and his power supply driving it he could be unsure if the output of the magnetron was exciting anything in the frustum from run to run.
http://forum.nasaspaceflight.com/index.php?topic=38577.msg1449178#msg1449178
Even after he did a modification to the magnetron to increase stability the Spectrum Analyzer still showed splatter and AM modulation all around the center tune frequency of the frustum.
Simply because of the splatter and AM modulation of the RF from the magnetron you could never be sure of a "lock" into a mode that might lead to thrust.
Shell -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rfmwguy on 12/18/2015 12:13 AM -
Q) Why is yours the first (and only) EM Drive test I know of that has to appeal to statistics to show an EM Drive force?
A) 1) Simplicity. Comparison between displacement track of beam with mag ON versus mag OFF. Lift track upwards was smooth/relatively linear and without stickiness during mag OFF (as heating started). 2) Lack of anyone willing to perform an analysis of thermal plumes or other potential error sources, including Lorentz force other than the horizontal vector; not applicable my tests imho.
Q) Am I correct that all the other tests (by Shawyer, Yang, NASA, Tajmar, Berca, etc.) claim that the EM Drive thrust in their tests is a reproducible effect, every time that the RF is turned on?
A) Not to my knowledge. All had several tests without measureable results.
Q) What (in your opinion) is responsible for the statistical nature of your tests, such that sometimes turning the magnetron ON had no measurable effect?
A) The use of a standard magnetron and (poorly filtered) power supply (in which I demonstrated afterwards with a spec an) did not always provide an instant, stable lock or frequency in comparison to lower power solid state sources or filtered power supplies. In addition, my VNA sweep of the frustum afterwards showed that frustum resonance was below average mag frequency.
As someone else said, I had planned to move to Phase II testing in 2016 with a goal of double-digit millinewton displacement numbers as compared to 177 micronewtons. This was also discussed here while you were away.
Unless someone demonstrates or points out a potential error source that approaches a triple-digit micronewton level, I will not chase those phantoms. Lorentz force in the horizontal axis falls into this category as does thermal plume turbulence (fluid analysis), imho. Show me a non-jet down force test result or example and I may take that off of my phantom list. There were no jets identified on the top plate emanating from the mag per my thermal scans, nor was there uneven heating of any of the outer surfaces; a clear sign of air jets.
So, statistics are most straight-forward way to analyze beam displacement variances between mag on and mag off cycles. No other error source hypothesis approaches the force level needed to interrupt the thermal lift track; Lorentz, air jets, plume turbulence, thermal expansion, etc., etc.
If anyone has other ideas...I'm all ears and will test for them if funding allows next year. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: oliverio on 12/18/2015 12:13 AM -
One question for you theoretical physicists, since my intuitions break down at the level of particle-wave duality.
I know it to be the case analytically that inside a resonant cavity, there exists a standing wave that will sometimes migrate too. Of course it cannot be the case that the energy itself is moving with the same velocity as the wavefront, because it would imply nearly stationary photons. Instead I assume I should conceive of this resonant cavity as containing an oscillating field rather than a set of bouncing quasiparticles.
However, that said, I have a new question: if one were measuring discrete points of this resonant field, would the energy density of the oscillating field be varying at the speed of light still? I.e. should I conceive of the resonant waveform as "one big phota" (pardon the pun) bouncing back and forth? Pardon the crude analogy, but a bit like a piece of jell-o being oscillated? -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/18/2015 12:19 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459316#msg1459316">Quote from: rfmwguy on 12/18/2015 12:13 AM</a>
Q) Am I correct that all the other tests (by Shawyer, Yang, NASA, Tajmar, Berca, etc.) claim that the EM Drive thrust in their tests is a reproducible effect, every time that the RF is turned on?
A) Not to my knowledge. All had several tests without measureable results.
What we are discussing is not that there were different results with different tests. What we are discussing is that it shows different results (including NO "anomalous force") , when turning the magnetron on at different times, during the same identical test.
Paul March has many tests were he shows the experimental measurement vs time. There is not a single such trace showing Paul March's results during the same test where he would get no experimental force when turning the RF on. The issue with NASA's test was one of drift of the baseline, and different shapes of the force trace, but never one of showing no force when the RF was turned on. NASA's measurements showed an experimental force trace measurement every time that the RF was turned on during the same test.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459316#msg1459316">Quote from: rfmwguy on 12/18/2015 12:13 AM</a>So, statistics are most straight-forward way to analyze beam displacement variances between mag on and mag off cycles.
A statistical analysis is unconvincing (and therefore not straightforward) for your tests because the sample population in your tests is way too small to arrive at a conclusion that your sample population is representative of the true statistical population, nor is the sample population large enough to determine what is the appropriate statistical distribution for a parametric test.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459316#msg1459316">Quote from: rfmwguy on 12/18/2015 12:13 AM</a>If anyone has other ideas...I'm all ears and will test for them if funding allows next year.
The following tests were suggested:
http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459176#msg1459176
http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459173#msg1459173
to show that there is an anomalous force in your tests that cannot be explained by transient thermal convection effects.
If interested in this you have to attempt to carry out the tests previously described, with the magnetron heated (ON and OFF) but not having RF going into the cavity.
If interested in understanding the fluid dynamic and lifting effects you have to take Schlerein optical videos to see what is actually happening when you are turning the magnetron on,and off, instead of assuming what is going on, based on intuition.
Either that or:
1) test in a vacuum, and hence eliminate all thermal convection effects
2) move the magnetron out of the way, and have RF coming into the cavity symmetrically as proposed by Shell.
I understand that you are saying that the effect is due to RF going into the cavity. I find that evidence lacking when you don't have tests conducted with the magnetron heated (ON and OFF) and no RF going into the cavity.
If you have the interest, it would be revealing at least to do the tests proposed with a heated magnetron (ON and OFF) without RF going into the cavity, to show that the effect is related to RF going into the cavity.
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rfmwguy on 12/18/2015 12:44 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459324#msg1459324">Quote from: Rodal on 12/18/2015 12:19 AM</a>
I left that determination up to a professional statistician. I did not get that pronouncement from them.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459316#msg1459316">Quote from: rfmwguy on 12/18/2015 12:13 AM</a>
Q) Am I correct that all the other tests (by Shawyer, Yang, NASA, Tajmar, Berca, etc.) claim that the EM Drive thrust in their tests is a reproducible effect, every time that the RF is turned on?
A) Not to my knowledge. All had several tests without measureable results.
What we are discussing about your test is not that it had different results with different tests. What we are discussing is that it shows different results (including NO "anomalous force") , when turning the magnetron on at different times, during the same identical test.
Paul March has many tests were he shows the experimental measurement vs time. There is not a single such trace showing Paul March's results during the same test where he would get no experimental force when turning the RF on. The issue with NASA's test was one of drift of the baseline, and different shapes of the force trace, but never one of showing no force when the RF was turned on. NASA's measurements showed an experimental force trace measurement every time that the RF was turned on during the same test.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459316#msg1459316">Quote from: rfmwguy on 12/18/2015 12:13 AM</a>So, statistics are most straight-forward way to analyze beam displacement variances between mag on and mag off cycles.
A statistical analysis is unconvincing (and therefore not straightforward) for your tests because the sample population in your tests is way too small to arrive at a conclusion that your sample population is representative of the true statistical population, nor is the sample population large enough to determine what is the appropriate statistical distribution for a parametric test.
We have a disagreement here. I have no problem with that. To convince me otherwise, I will need data that demonstrates the possibility of triple digit micronewton force generation in a vertical axis. Lorentz is out. If you have another specific error source in mind, lets hear it. Point me to some examples. My eyes and mind are open. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/18/2015 12:50 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459338#msg1459338">Quote from: rfmwguy on 12/18/2015 12:44 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459324#msg1459324">Quote from: Rodal on 12/18/2015 12:19 AM</a>
...A statistical analysis is unconvincing (and therefore not straightforward) for your tests because the sample population in your tests is way too small to arrive at a conclusion that your sample population is representative of the true statistical population, nor is the sample population large enough to determine what is the appropriate statistical distribution for a parametric test.
I left that determination up to a professional statistician. I did not get that pronouncement from them.
We have a disagreement here. I have no problem with that. ...
I have not seen a statistical argument in these threads disagreeing with the fact that the sample population in your tests is way too small (to arrive at a conclusion that your sample population is representative of the true statistical population). Therefore I have not seen a justification that you can use only statistical tests to arrive at a robust statistical conclusion based on your test results.
PS: I am a member of the American Statistical Association, and use statistical models (as well as information theory) to make a living.
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Tetrakis on 12/18/2015 12:56 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459316#msg1459316">Quote from: rfmwguy on 12/18/2015 12:13 AM</a>
As someone else said, I had planned to move to Phase II testing in 2016 with a goal of double-digit millinewton displacement numbers as compared to 177 micronewtons. This was also discussed here while you were away.
Unless someone demonstrates or points out a potential error source that approaches a triple-digit micronewton level, I will not chase those phantoms. Lorentz force in the horizontal axis falls into this category as does thermal plume turbulence (fluid analysis), imho. Show me a non-jet down force test result or example and I may take that off of my phantom list. There were no jets identified on the top plate emanating from the mag per my thermal scans, nor was there uneven heating of any of the outer surfaces; a clear sign of air jets.
So, statistics are most straight-forward way to analyze beam displacement variances between mag on and mag off cycles. No other error source hypothesis approaches the force level needed to interrupt the thermal lift track; Lorentz, air jets, plume turbulence, thermal expansion, etc., etc.
If anyone has other ideas...I'm all ears and will test for them if funding allows next year.
I think 100mg in such a large, hot setup in air is at least in the ballpark of thermal convection forces. Simply opening the doors of a milligram balance can throw it off by about ten milligrams. As I said about 150 pages ago in this thread, such a small force can't really be considered a positive result. You have two effects, poorly characterized air currents and "the EMDrive effect" (Or, as some troublingly refer to it, "Thrust"), but without either high vacuum or, as you aim to achieve, large forces, you can't convincingly disentangle them. You are right that characterizing these thermal effects would be like chasing phantoms, and this is exactly why any statistically significant values you obtain are suspect.
If you want to answer your question about whether or not the EMdrive works, you should do what you propose: design a better, more robust experiment with a higher expected S/N ratio. But just as importantly, you need to define a null hypothesis before you carry out that experiment. If you continue your tests with this better device, what evidence would indicate that it doesn't work? -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: OnlyMe on 12/18/2015 01:04 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459316#msg1459316">Quote from: rfmwguy on 12/18/2015 12:13 AM</a>
Q) Why is yours the first (and only) EM Drive test I know of that has to appeal to statistics to show an EM Drive force?
A) 1) Simplicity. Comparison between displacement track of beam with mag ON versus mag OFF. Lift track upwards was smooth/relatively linear and without stickiness during mag OFF (as heating started). 2) Lack of anyone willing to perform an analysis of thermal plumes or other potential error sources, including Lorentz force other than the horizontal vector; not applicable my tests imho.
Q) Am I correct that all the other tests (by Shawyer, Yang, NASA, Tajmar, Berca, etc.) claim that the EM Drive thrust in their tests is a reproducible effect, every time that the RF is turned on?
A) Not to my knowledge. All had several tests without measureable results.
Q) What (in your opinion) is responsible for the statistical nature of your tests, such that sometimes turning the magnetron ON had no measurable effect?
A) The use of a standard magnetron and (poorly filtered) power supply (in which I demonstrated afterwards with a spec an) did not always provide an instant, stable lock or frequency in comparison to lower power solid state sources or filtered power supplies. In addition, my VNA sweep of the frustum afterwards showed that frustum resonance was below average mag frequency.
As someone else said, I had planned to move to Phase II testing in 2016 with a goal of double-digit millinewton displacement numbers as compared to 177 micronewtons. This was also discussed here while you were away.
Unless someone demonstrates or points out a potential error source that approaches a triple-digit micronewton level, I will not chase those phantoms. Lorentz force in the horizontal axis falls into this category as does thermal plume turbulence (fluid analysis), imho. Show me a non-jet down force test result or example and I may take that off of my phantom list. There were no jets identified on the top plate emanating from the mag per my thermal scans, nor was there uneven heating of any of the outer surfaces; a clear sign of air jets.
So, statistics are most straight-forward way to analyze beam displacement variances between mag on and mag off cycles. No other error source hypothesis approaches the force level needed to interrupt the thermal lift track; Lorentz, air jets, plume turbulence, thermal expansion, etc., etc.
If anyone has other ideas...I'm all ears and will test for them if funding allows next year.
If you can isolate the current frustum in a outer can essentially, the whole device could be encased in a cast high temperature resistant material. Preferably in separate sections so it could be disassembled without destruction. Weight should not real be a problem for the balance beam. The outer thermally resistant casting should slow down any exterior convection based thermal effects and by controlling the shape make modeling what exterior thermal effects there are easier to model. The outer cast material can also be sealed to eliminate out gassing and any ballooning, and being ridged resolve ballooning.
Casting material that can stand 2600-3000 degrees F is available.
You would have to tune the frustum and then seal the final portion of the casing..., preventing any additional tuning.
The material I was thinking of is normally used in making forges. It is ridged and depending on how thick the casting is would act as a thermal barrier and heat sink initially and provide more uniform heat dispation as it heats up. This material should be able to handle even the magnetron at 100%... No warrantee how long the magnetron could handle it.
PS it would probably work better for a solid copper frustum where each of the three pieces could have a separately cast part and there would hopefully be a larger thrust signal to work with. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: oliverio on 12/18/2015 01:13 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459356#msg1459356">Quote from: OnlyMe on 12/18/2015 01:04 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459316#msg1459316">Quote from: rfmwguy on 12/18/2015 12:13 AM</a>
Q) Why is yours the first (and only) EM Drive test I know of that has to appeal to statistics to show an EM Drive force?
A) 1) Simplicity. Comparison between displacement track of beam with mag ON versus mag OFF. Lift track upwards was smooth/relatively linear and without stickiness during mag OFF (as heating started). 2) Lack of anyone willing to perform an analysis of thermal plumes or other potential error sources, including Lorentz force other than the horizontal vector; not applicable my tests imho.
Q) Am I correct that all the other tests (by Shawyer, Yang, NASA, Tajmar, Berca, etc.) claim that the EM Drive thrust in their tests is a reproducible effect, every time that the RF is turned on?
A) Not to my knowledge. All had several tests without measureable results.
Q) What (in your opinion) is responsible for the statistical nature of your tests, such that sometimes turning the magnetron ON had no measurable effect?
A) The use of a standard magnetron and (poorly filtered) power supply (in which I demonstrated afterwards with a spec an) did not always provide an instant, stable lock or frequency in comparison to lower power solid state sources or filtered power supplies. In addition, my VNA sweep of the frustum afterwards showed that frustum resonance was below average mag frequency.
As someone else said, I had planned to move to Phase II testing in 2016 with a goal of double-digit millinewton displacement numbers as compared to 177 micronewtons. This was also discussed here while you were away.
Unless someone demonstrates or points out a potential error source that approaches a triple-digit micronewton level, I will not chase those phantoms. Lorentz force in the horizontal axis falls into this category as does thermal plume turbulence (fluid analysis), imho. Show me a non-jet down force test result or example and I may take that off of my phantom list. There were no jets identified on the top plate emanating from the mag per my thermal scans, nor was there uneven heating of any of the outer surfaces; a clear sign of air jets.
So, statistics are most straight-forward way to analyze beam displacement variances between mag on and mag off cycles. No other error source hypothesis approaches the force level needed to interrupt the thermal lift track; Lorentz, air jets, plume turbulence, thermal expansion, etc., etc.
If anyone has other ideas...I'm all ears and will test for them if funding allows next year.
If you can isolate the current frustum in a outer can essentially, the whole device could be encased in a cast high temperature resistant material. Preferably in separate sections so it could be disassembled without destruction. Weight should not real be a problem for the balance beam. The outer thermally resistant casting should slow down any exterior convection based thermal effects and by controlling the shape make modeling what exterior thermal effects there are easier to model. The outer cast material can also be sealed to eliminate out gassing and any ballooning, and being ridged resolve ballooning.
Casting material that can stand 2600-3000 degrees F is available.
You would have to tune the frustum and then seal the final portion of the casing..., preventing any additional tuning.
The material I was thinking of is normally used in making forges. It is ridged and depending on how thick the casting is would act as a thermal barrier and heat sink initially and a provide more uniform heat dispation as it heats up. This material should be able to handle even the magnetron at 100%... Not warrantee how long the magnetron could handle it.
At this rate why not just pack the box with sand? Its specific heat is large I believe, and intuition tells me that a very hot object inside a box of sand will be cool to the touch after some massive internal heat flux. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: OnlyMe on 12/18/2015 01:15 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459360#msg1459360">Quote from: oliverio on 12/18/2015 01:13 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459356#msg1459356">Quote from: OnlyMe on 12/18/2015 01:04 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459316#msg1459316">Quote from: rfmwguy on 12/18/2015 12:13 AM</a>
Q) Why is yours the first (and only) EM Drive test I know of that has to appeal to statistics to show an EM Drive force?
A) 1) Simplicity. Comparison between displacement track of beam with mag ON versus mag OFF. Lift track upwards was smooth/relatively linear and without stickiness during mag OFF (as heating started). 2) Lack of anyone willing to perform an analysis of thermal plumes or other potential error sources, including Lorentz force other than the horizontal vector; not applicable my tests imho.
Q) Am I correct that all the other tests (by Shawyer, Yang, NASA, Tajmar, Berca, etc.) claim that the EM Drive thrust in their tests is a reproducible effect, every time that the RF is turned on?
A) Not to my knowledge. All had several tests without measureable results.
Q) What (in your opinion) is responsible for the statistical nature of your tests, such that sometimes turning the magnetron ON had no measurable effect?
A) The use of a standard magnetron and (poorly filtered) power supply (in which I demonstrated afterwards with a spec an) did not always provide an instant, stable lock or frequency in comparison to lower power solid state sources or filtered power supplies. In addition, my VNA sweep of the frustum afterwards showed that frustum resonance was below average mag frequency.
As someone else said, I had planned to move to Phase II testing in 2016 with a goal of double-digit millinewton displacement numbers as compared to 177 micronewtons. This was also discussed here while you were away.
Unless someone demonstrates or points out a potential error source that approaches a triple-digit micronewton level, I will not chase those phantoms. Lorentz force in the horizontal axis falls into this category as does thermal plume turbulence (fluid analysis), imho. Show me a non-jet down force test result or example and I may take that off of my phantom list. There were no jets identified on the top plate emanating from the mag per my thermal scans, nor was there uneven heating of any of the outer surfaces; a clear sign of air jets.
So, statistics are most straight-forward way to analyze beam displacement variances between mag on and mag off cycles. No other error source hypothesis approaches the force level needed to interrupt the thermal lift track; Lorentz, air jets, plume turbulence, thermal expansion, etc., etc.
If anyone has other ideas...I'm all ears and will test for them if funding allows next year.
If you can isolate the current frustum in a outer can essentially, the whole device could be encased in a cast high temperature resistant material. Preferably in separate sections so it could be disassembled without destruction. Weight should not real be a problem for the balance beam. The outer thermally resistant casting should slow down any exterior convection based thermal effects and by controlling the shape make modeling what exterior thermal effects there are easier to model. The outer cast material can also be sealed to eliminate out gassing and any ballooning, and being ridged resolve ballooning.
Casting material that can stand 2600-3000 degrees F is available.
You would have to tune the frustum and then seal the final portion of the casing..., preventing any additional tuning.
The material I was thinking of is normally used in making forges. It is ridged and depending on how thick the casting is would act as a thermal barrier and heat sink initially and a provide more uniform heat dispation as it heats up. This material should be able to handle even the magnetron at 100%... Not warrantee how long the magnetron could handle it.
At this rate why not just pack the box with sand? Its specific heat is large I believe, and intuition tells me that a very hot object inside a box of sand will be cool to the touch after some massive internal heat flux.
The current frustum is made of a wire mesh.
... And I am unsure how the magnetron would react to being packed in sand. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: ThereIWas3 on 12/18/2015 01:31 AM - Another way to eliminate air around the frustum, besides a vacuum, is to fill the space with expanding plastic foam. Put frustrum in a 30cm cubic box. Attach wires. Blow expanding plastic foam like used for insulation into the box. Allow to harden. Scrape off excess. Attach lid. Place on scale apparatus. Apply power. Repeat in all possible orientations.
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: OnlyMe on 12/18/2015 01:50 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459371#msg1459371">Quote from: ThereIWas3 on 12/18/2015 01:31 AM</a>
Another way to eliminate air around the frustum, besides a vacuum, is to fill the space with expanding plastic foam. Put frustrum in a 30cm cubic box. Attach wires. Blow expanding plastic foam like used for insulation into the box. Allow to harden. Scrape off excess. Attach lid. Place on scale apparatus. Apply power. Repeat in all possible orientations.
In the case of rfmwguy's current frustum the magnetron is on top and heats up to between 150 and 200 degrees C. The foam is flamible. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rq3 on 12/18/2015 02:08 AM -
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SeeShells on 12/18/2015 02:11 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459277#msg1459277">Quote from: Flyby on 12/17/2015 10:29 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458920#msg1458920">Quote from: Rodal on 12/17/2015 11:49 AM</a>
.....
A few weeks ago, I used those Yang plots to determine the efficiency of her EMdrive while the input power increased.
2) The experimental results of Prof. Yang showed strong nonlinearity between the measured force and the input power (see attached chart). Prof. Yang's experiments show diminishing returns (actually slight decrease in measured forces for input power exceeding 300 Watts and general flat response) for increasing input power.
Hence it does not follow that the thermal artifacts will scale linearly in experiments conducted at much higher input power. On the contrary, Prof. Yang's experimental results show strong nonlinearity, with the touted "EM Drive" force dependence on input power effectively dissappearing after about 300 watts, the dependence looks practically flat at input powers greater than 300 W. The nonlinearity of the "force" vs. input power experimental relation of Prof. Yang has not yet been scientifically modeled hence its nature can only be speculated until a verifiable model is demonstrated.
This shows that if anything, experiments conducted at ambient conditions with low power may be highly misleading and NOT linearly scalable to higher powers, just as it would be highly misleading to conflate the flight of an insect with the flight of an airplane (the aerodynamics are completely different at very low Reynolds numbers).(The range of Reynolds number in insect flight is about 10 to 10^4, which lies in between the two limits that are convenient for theories that try to simplify the nonlinearity of Navier Stokes fluid dynamics: inviscid steady flows around an airplane's airfoil and Stokes flow experienced by a swimming bacterium. For this reason, this intermediate Reynolds number range used by insects in their flight is not as well understood as the high Reynolds number regime for airplanes. )
What I did is to bring all generated forces back to 1kW of power to get an idea how her frustum performed while she gradually increased the power...
It didn't show a straight linear relation, but a steep decline in efficiency at first, then leveled out for a long period and at the end showed improvement again, which might hint that a drastic increase in power "might" yield better then expected results.
I find it puzzling to why it stayed almost completely level from around 800W up to 2200W...
The performance degrading from 300W to 700W is probably due to thermal effects?
Nice workup, looking forward to comparing step mode in my tests to see how well I've mitigated thermal issues in keeping the tune for a mode.
Shell
PS: The data and the way they built their frustum does seem to point to a thermal deformation mode resonance shifting until the power slope band width starts to run into more resonance.
This isn't Yang's Spectrum but just one I picked for show and tell. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Flyby on 12/18/2015 08:26 AM -
Well, what I take out of it is that in order to get a better, clear signal out of the (thermal) noise zone, you either should go for a 200-300W input power or further increase beyond 2500W...
As power is directly related to the thermal effects( buoyancy, material deformation, etc) the ratio of produced force/power needs to be as big as possible to get the best results with the least negative effects.
Too bad we don't have the relation of power/buoyancy (causing additional forces) or power/material deformation (causing frequency shifting, hence less force generation?). That would be interesting to pit those 3 graphs against each other.
Again, although I do play along as if it works, there is certainly no evidence it does. I remain a skeptic until proven otherwise...
Only, one has to engage into it, to investigate the possible effect. So for the sake of investigation and experimenting, one can not do anything else then pretend... :)
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Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: RERT on 12/18/2015 09:45 AM -
Forgive me for using a single post to respond to multiple others, but hopefully this won't be too confusing.
1. I thought I heard RFMWGUY a few posts back saying indirectly he might give up without perfect isolation of thermal effects. Don't!
You can essentially eliminate thermal effects: as I've suggested before (and I think Space Ghost 1962 was thinking along similar lines) use electric heaters and thermostats to keep the rig at a constant temperature irrespective of whether or not the frustrum is powered. Run tests long enough for the system to generate numbers while at thermal equilibrium. Run control tests without frustrum power. Do both with the frustrum in different up/down/left/right orientations.
Yes, the fact that the whole thing is above ambient temp will create airflow and 'vortex shedding', but this will be the same with and without thrust, if any exists. You don't need to calculate the effects precisely if that is true. With enough runs I'm sure you will find a signal if it's there and is large enough.
If you do this and find an effect, then you can worry about residual errors.
2. Number of repetitions required to identify signal
I think it is profitable to consider every on/off cycle of frustrum power, while at thermal equilibrium, as a separate event. Dynamic response over hundreds of power cycles may reveal more than the gross averages of one or two experiments.
3. OnlyMe at post 196 on dark matter/energy
The courses I took on general relativity and cosmology are now over 34 years ago, so it's fair to say I'm eager to avoid a detailed debate with someone more current!
I acknowledge what you say about dark energy being an extra term in GR equations, not a balancing item for conservation of energy. However, consider this: dark energy implies (so I read) an energy density for the vacuum, and a total energy which changes as the universe expands. If the theory including dark energy has the total energy of the universe conserved, it's very hard to see how the same observed dynamical behaviour is consistent with the conservation of energy in the Universe absent dark energy. In that sense, dark energy is a balancing item for CoE.
I realize the topic might be conceptually slippery, and I may be wrong. I'd be interested in any response.
R.
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Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: glennfish on 12/18/2015 01:01 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459343#msg1459343">Quote from: Rodal on 12/18/2015 12:50 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459338#msg1459338">Quote from: rfmwguy on 12/18/2015 12:44 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459324#msg1459324">Quote from: Rodal on 12/18/2015 12:19 AM</a>
...A statistical analysis is unconvincing (and therefore not straightforward) for your tests because the sample population in your tests is way too small to arrive at a conclusion that your sample population is representative of the true statistical population, nor is the sample population large enough to determine what is the appropriate statistical distribution for a parametric test.
I left that determination up to a professional statistician. I did not get that pronouncement from them.
We have a disagreement here. I have no problem with that. ...
I have not seen a statistical argument in these threads disagreeing with the fact that the sample population in your tests is way too small (to arrive at a conclusion that your sample population is representative of the true statistical population). Therefore I have not seen a justification that you can use only statistical tests to arrive at a robust statistical conclusion based on your test results.
PS: I am a member of the American Statistical Association, and use statistical models (as well as information theory) to make a living.
Dr. Rodal,
On the statistical analysis, I'm the target, not RFMWGUY. Any faults in that analysis are mine, not his.
1st. I agree on the sample size issues. My first request after that run were replication runs to characterize things more fully. Unfortunately he had disassembled his setup at that point and was unable to comply.
2nd. The data collection was not designed with a statistical analysis in mind. It required "post-hoc" data mining to pull about 40 mag on / mag off sample sub-sets out of a single run. The data resolution only permitted between 10 and 15 data points per on or off cycle, which in itself is a small sample. Ideally, the data would have been sampled at a much higher rate permitting higher resolution, but it was what it was.
3rd. The analysis that indicated anomalous behavior was based on a suggestion that there would be a difference in the mag-on behavior vs the mag-off behavior, specifically, that the mag on behavior would change during the mag-on cycle. That was not an a-prior assumption. Given that suggestion, it was possible to establish that for this one run, of about 40 cycles, of 10-15 data points per cycle, that the slope behavior for mag-on was statistically significantly different than the mag-off behavior, for the 40 odd sub-sets of that single run. That analysis with raw data was provided in this forum and is referenced in RFMWGUYs report. The algorithms that extracted the data for analysis are included in those uploads and include live VBA code if anyone wants to replicate/critique.
4th. The analysis could not confirm or deny any hypothesis beyond the slope behavior was different given these constraints. As to the cause, the magnitude, the why, post-hoc analysis with a post-hoc experimental design as we both know is the worst possible world. However, the data is indicative of some kind of signal in the noise, which is different from no signal in the noise.
5th. If you review my commentaries in this forum on methods, sampling, experimental design, etc. you see that I'm a fellow traveler on getting this right and up front.
IMHO, RFMWGUY's data shows a signal of some kind in that one run of 40 odd sub-samples. I don't know what that means, and even if it's statistically significant for that one run, which it is, I am in no position to state if it was thrust, delayed thermals, or unicorn dust.
IMHO, the next round of tests requires multiple runs under multiple criteria pre-defined carefully before the power is turned on. I'd be pleased to exchange methodology suggestions with you and if you have specific critiques of the actual data reduction techniques and analysis, I'd love the debate. At that time, the only statistical feedback I got in the forum was "so you have statistically proven that the EMDrive produces thrust?" That was most unhelpful feedback. :)
Finally, the ideal model would state something like "when I turn the power on I will see x micro-newtons of thrust" and you design the experiment to see if you get x or something else. In this case, since there is no accepted theory, and hence no means of calculating x in advance, the first question to me is simply, can you find x > 0. From my point of view, that pushes the DIY testing into the domain of statistical analysis, and if x is greater than 0, statistically, then maybe we can come up with something that says x = f(stuff). From an engineering and physics point of view, stuff is a lot of possible things that hopefully the DIY folks can gradually reduce from known items like thermals, airflow, Lorenz, etc., until there is either no residual to account for, or there is. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/18/2015 01:06 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459512#msg1459512">Quote from: glennfish on 12/18/2015 01:01 PM</a>
Thank you for your nicely written, objective reply. There is no debate between us. Great, sound suggestions.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459343#msg1459343">Quote from: Rodal on 12/18/2015 12:50 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459338#msg1459338">Quote from: rfmwguy on 12/18/2015 12:44 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459324#msg1459324">Quote from: Rodal on 12/18/2015 12:19 AM</a>...A statistical analysis is unconvincing (and therefore not straightforward) for your tests because the sample population in your tests is way too small to arrive at a conclusion that your sample population is representative of the true statistical population, nor is the sample population large enough to determine what is the appropriate statistical distribution for a parametric test.
I left that determination up to a professional statistician. I did not get that pronouncement from them.
We have a disagreement here. I have no problem with that. ...
I have not seen a statistical argument in these threads disagreeing with the fact that the sample population in your tests is way too small (to arrive at a conclusion that your sample population is representative of the true statistical population). Therefore I have not seen a justification that you can use only statistical tests to arrive at a robust statistical conclusion based on your test results.
PS: I am a member of the American Statistical Association, and use statistical models (as well as information theory) to make a living.
Dr. Rodal,
On the statistical analysis, I'm the target, not RFMWGUY. Any faults in that analysis are mine, not his.
1st. I agree on the sample size issues. My first request after that run were replication runs to characterize things more fully. Unfortunately he had disassembled his setup at that point and was unable to comply.
2nd. The data collection was not designed with a statistical analysis in mind. It required "post-hoc" data mining to pull about 40 mag on / mag off sample sub-sets out of a single run. The data resolution only permitted between 10 and 15 data points per on or off cycle, which in itself is a small sample. Ideally, the data would have been sampled at a much higher rate permitting higher resolution, but it was what it was.
3rd. The analysis that indicated anomalous behavior was based on a suggestion that there would be a difference in the mag-on behavior vs the mag-off behavior, specifically, that the mag on behavior would change during the mag-on cycle. That was not an a-prior assumption. Given that suggestion, it was possible to establish that for this one run, of about 40 cycles, of 10-15 data points per cycle, that the slope behavior for mag-on was statistically significantly different than the mag-off behavior, for the 40 odd sub-sets of that single run. That analysis with raw data was provided in this forum and is referenced in RFMWGUYs report. The algorithms that extracted the data for analysis are included in those uploads and include live VBA code if anyone wants to replicate/critique.
4th. The analysis could not confirm or deny any hypothesis beyond the slope behavior was different given these constraints. As to the cause, the magnitude, the why, post-hoc analysis with a post-hoc experimental design as we both know is the worst possible world. However, the data is indicative of some kind of signal in the noise, which is different from no signal in the noise.
5th. If you review my commentaries in this forum on methods, sampling, experimental design, etc. you see that I'm a fellow traveler on getting this right and up front.
IMHO, RFMWGUY's data shows a signal of some kind in that one run of 40 odd sub-samples. I don't know what that means, and even if it's statistically significant for that one run, which it is, I am in no position to state if it was thrust, delayed thermals, or unicorn dust.
IMHO, the next round of tests requires multiple runs under multiple criteria pre-defined carefully before the power is turned on. I'd be pleased to exchange methodology suggestions with you and if you have specific critiques of the actual data reduction techniques and analysis, I'd love the debate. At that time, the only statistical feedback I got in the forum was "so you have statistically proven that the EMDrive produces thrust?" That was most unhelpful feedback. :)
Finally, the ideal model would state something like "when I turn the power on I will see x micro-newtons of thrust" and you design the experiment to see if you get x or something else. In this case, since there is no accepted theory, and hence no means of calculating x in advance, the first question to me is simply, can you find x > 0. From my point of view, that pushes the DIY testing into the domain of statistical analysis, and if x is greater than 0, statistically, then maybe we can come up with something that says x = f(stuff). From an engineering and physics point of view, stuff is a lot of possible things that hopefully the DIY folks can gradually reduce from known items like thermals, airflow, Lorenz, etc., until there is either no residual to account for, or there is.
It is unfortunate that the experimental setup was disassembled at the point of your involvement, as the scientific method is a continuous loop, ongoing process, and it is better not halted:
()
Other experiments are ongoing and being planned, which will clarify what is going on.
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: OnlyMe on 12/18/2015 01:49 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459452#msg1459452">Quote from: Flyby on 12/18/2015 08:26 AM</a>
Well, what I take out of it is that in order to get a better, clear signal out of the (thermal) noise zone, you either should go for a 200-300W input power or further increase beyond 2500W...
As power is directly related to the thermal effects( buoyancy, material deformation, etc) the ratio of produced force/power needs to be as big as possible to get the best results with the least negative effects.
.....
Initially I had a similar thought. The problem is Yang never provided enough information about her microwave generation setup aside from mentioning it involved a magnetron. Add.....
Yang provided the following in her 2013 paper,
"... the practical maximum microwave output power is 13 W, 120 W, 85 W, 65 W, 45 W, and 48 W respectively at the nominal output power 200 W, 300 W, 400 W, 500 W, 600 W, and 700 W."
The practical maximums above fit well with the thrust mN in the graph linked below.
http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=39004.0;attach=1087396 (http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=39004.0;attach=1087396)
Without better specifics from Yang the nominal output - raw power-in figures are of little real value, since it is unknown why there is a better practical output at 300 watts, that falls until at 700 watts it has returned to nearly an identical efficiency as it began at 200. It would be better to use the practical maximums of 13 W, 120 W, 85 W, 65 W, 45 W, and 48.
This might suggest that a cleaner initial microwave source would be better... But even that is guesswork without specific information from Yang and Shawyer.., or a great deal more independent test results... So we wait now for Shell to feel better. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: glennfish on 12/18/2015 01:55 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459465#msg1459465">Quote from: RERT on 12/18/2015 09:45 AM</a>
1. I thought I heard RFMWGUY a few posts back saying indirectly he might give up without perfect isolation of thermal effects. Don't!
Stating agreement.
There are many ways to isolate thermal effects. The harder ways and the easier ways. The harder ways are to spend a gazillion hours designing and building so that the physical device has no thermals. IMHO you can never succeed in that approach.
The easy way is to get the thermal behavior to become highly repeatable to the point where you can calculate it exactly with a tiny error confidence interval. When thermals become a calculable function, with a tiny Standard Deviation, you literally subtract out the thermals and start looking for a signal. Lots of ways to do that mathematically & statistically.
IMHO thermals are almost certainly an exact function of total joules per second, frustum temperature & ambient air temperature and ambient air pressure and you can almost certainly come up with an exact equation for a given frustum design that accurately predicts thermal effects. A few trials focused on the thermals only, will quickly produce an equation that can be subtracted from runs where you're trying to see thrust. To get the standard deviation to its minimum will require a modest number of thermal only runs, but once you have that equation for that frustum/mag combination, anything that deviates from that equation is a signal of some kind.
I would invest in a thermocouple or two rather than design a thermally controlled frustum. :) -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/18/2015 01:57 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1458834#msg1458834">Quote from: ZhixianLin on 12/17/2015 08:28 AM</a>
Hey, why not try my design. I think it is easier to understand.
Thank you for your contribution and welcome to the EM Drive thread :)
Here it is:
http://forum.nasaspaceflight.com/index.php?topic=38996.0
There are many issues for discussion on your report, for example, to pick one:
If a force were to be produced, then work would be done when the electromagnetic engine moves in space (Work = Force * displacement). If the force is produced without energy radiation (or mass outflow), the work is performed without spending energy. Then, the proposed electromagnetic device would be a perpetual-motion machine.
As (I think it was first aptly remarked by Frobnicat in these threads) it is curious that proponents of propellant-less electromagnetic space propulsion that don't rely on external fields for propulsion, like electromagnetic tethers, etc., seem to avoid the consequence of their device being a perpetual motion machine. If the device is a perpetual motion machine, it could be used for energy purposes here on Earth, which prompts the question as to why such discussions (of using their electromagnetic self-accelerators for energy production on Earth instead of for transportation purposes) not addressed. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Flyby on 12/18/2015 02:07 PM -
After refreshing my knowledge about angular momentum and gyroscope behavior and combining that with a detailed study of pictures of Shawyer's "EMdrive on a rotating table", I'm inclined to say that zen-in was (partially) right...
Although I differ from opinion with him that it is not_so_much the sloshing of the water,because much of the directions cancel each other out (tubing in all directions) but the angular momentum of pump motor that is at cause.
I'm kinda perplexed that for an engineer, Shawyer did not think about that.
The more that the problem could have been easily solved simply by re-aligning the pump 90° and let the plane cross the axis of the air-bearing. I'll add some pictures later on.
to illustrate more visually what i mean :
https://www.youtube.com/watch?v=NeXIV-wMVUk
It is not hard to see the very same setup on the EMdrive test rig, except, instead of hanging it on a rope, it floats on an air-bearing spindle, but the rotation of the pump is in exact the same position as the wheel in the video.. and will consequently most likely also make the table turn.
Bottom line is that the credibility of that test entirely depends on the rotation direction of that pump...sad and somewhat disappointing...but true...
I'd say there is a very high probability (50%, depending on the direction the pump motor turns) that the table turns, not due to an EMdrive effect, but simply because of a gyroscopic effect...
not to say...but my confidence in this type of EMtest has been seriously dented. If anything should be replicated it will first, and before anything else, need to solve the torque issue.
added:
From the video Shawyer posted it is impossible to see when the pump was activated. Was the pump already running BEFORE the magnetron was turned on? If not, if it was turned on at the same moment the magnetron was turned on, what direction does it spin?
Does the rig still exists and is it possible to do just a dry run with only the pump running?
Those are legitimate questions that only Shawyer can answer.
If he wants to keep his credibility i think it would be in his best interest to answer these. This is not bullying or hand waving... just some credible engineering questions...
Maybe TT could slip these questions through to him and hope for an answer? -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: RotoSequence on 12/18/2015 03:09 PM -
http://i.imgur.com/DUnuPMF.gifv
Always fun to watch wave propagation in other mediums and wonder how this stuff might all be connected. :) -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: lmbfan on 12/18/2015 03:57 PM -
I attempted to do a software analysis of the simple geometry in my last post (based on dimensions and picture provided by rmfwguy), and I ran into a few issues. One is purely software related and I will research that one on my own, however, the following will need to be answered to a reasonable degree of certainty before any accurate analysis is done:
1) Please verify for the galvanized steel housings, specific heat of 490 J/(kg K)
2) Please verify thermal conductivity - engineeringtoolbox.com specifies a range of 6-26 W/(m K)
3) Wattage of the magnetron that is converted to heat (i.e. how many Watts is the heat source?)
4) Please verify density of housing is 7.85 g/cm^3
5) Convection coefficient for convection (I found something that said it was ~10.45 kg/(sec^3 C) for air at 0 m/s)
I may have more questions as I delve further into this. I will, of course, do my best to answer any issues myself, however, if someone can verify with a minimum of effort and save me hours of research time, assistance would be greatly appreciated. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rfmwguy on 12/18/2015 04:36 PM -
1) Please verify for the galvanized steel housings, specific heat of 490 J/(kg K)
a) It is galvanized steel.
2) Please verify thermal conductivity - engineeringtoolbox.com specifies a range of 6-26 W/(m K)
a) Cannot help here
3) Wattage of the magnetron that is converted to heat (i.e. how many Watts is the heat source?)
a) 900 watts
4) Please verify density of housing is 7.85 g/cm^3
a) cannot help here
5) Convection coefficient for convection (I found something that said it was ~10.45 kg/(sec^3 C) for air at 0 m/s)
a) cannot help here
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: zen-in on 12/18/2015 05:08 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459549#msg1459549">Quote from: Flyby on 12/18/2015 02:07 PM</a>
After refreshing my knowledge about angular momentum and gyroscope behavior and combining that with a detailed study of pictures of Shawyer's "EMdrive on a rotating table", I'm inclined to say that zen-in was (partially) right...
Although I differ from opinion with him that it is not_so_much the sloshing of the water,because much of the directions cancel each other out (tubing in all directions) but the angular momentum of pump motor that is at cause.
I'm kinda perplexed that for an engineer, Shawyer did not think about that.
The more that the problem could have been easily solved simply by re-aligning the pump 90° and let the plane cross the axis of the air-bearing. I'll add some pictures later on.
U-toob was here
It is not hard to see the very same setup on the EMdrive test rig, except, instead of hanging it on a rope, it floats on an air-bearing spindle, but the rotation of the pump is in exact the same position as the wheel in the video.. and will consequently most likely also make the table turn.
Bottom line is that the credibility of that test entirely depends on the rotation direction of that pump...sad and somewhat disappointing...but true...
I'd say there is a very high probability (50%, depending on the direction the pump motor turns) that the table turns, not due to an EMdrive effect, but simply because of a gyroscopic effect...
not to say...but my confidence in this type of EMtest has been seriously dented. If anything should be replicated it will first, and before anything else, need to solve the torque issue.
added:
From the video Shawyer posted it is impossible to see when the pump was activated. Was the pump already running BEFORE the magnetron was turned on? If not, if it was turned on at the same moment the magnetron was turned on, what direction does it spin?
Does the rig still exists and is it possible to do just a dry run with only the pump running?
Those are legitimate questions that only Shawyer can answer.
If he wants to keep his credibility i think it would be in his best interest to answer these. This is not bullying or hand waving... just some credible engineering questions...
Maybe TT could slip these questions through to him and hope for an answer?
I don't believe gyroscopic precession can be used to explain Shawyer's video. The pump is not spinning fast enough for gyroscopic effects. But just having a motor mounted with its shaft parallel to the rotational axis of the apparatus is enough to start it rotating. Several years ago I mounted a motor on a rotating table. When the motor was spun up the table rotated. When the motor was switched off the table rotated back to its original position. We don't now enough about Shawyers apparatus to be able to analyze what is happening. That's why the focus has been on DIY experiments. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SteveD on 12/18/2015 05:09 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459316#msg1459316">Quote from: rfmwguy on 12/18/2015 12:13 AM</a>
Unless someone demonstrates or points out a potential error source that approaches a triple-digit micronewton level, I will not chase those phantoms. Lorentz force in the horizontal axis falls into this category as does thermal plume turbulence (fluid analysis), imho. Show me a non-jet down force test result or example and I may take that off of my phantom list. There were no jets identified on the top plate emanating from the mag per my thermal scans, nor was there uneven heating of any of the outer surfaces; a clear sign of air jets.
So, statistics are most straight-forward way to analyze beam displacement variances between mag on and mag off cycles. No other error source hypothesis approaches the force level needed to interrupt the thermal lift track; Lorentz, air jets, plume turbulence, thermal expansion, etc., etc.
If anyone has other ideas...I'm all ears and will test for them if funding allows next year.
Well I had thought that the transformer hum might have vibrated the hot air trapped in the heat sink chamber, causing more of it to spill out, reducing lift. Would think that this would have shown up clearly on the thermal camera though. Best was I can think of to test for this would be simply proceeding as planned. If you remove the magnetron from the top of the thing and it goes down more with higher Q . . . well that's interesting.
I think the big problem with mangetrons are that their outputs can take a random walk. Sometimes you get very little in resonance and sometimes you get more. Statistics would seem to be an excellent way of dealing with an rf source given to random walks.
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: zen-in on 12/18/2015 05:19 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459215#msg1459215">Quote from: rfmwguy on 12/17/2015 08:54 PM</a>
...
Doc, while it was not consistent each time, its easy to see from the video of the mag spectrum that its own rf stability is more likely the cause rather than a transient thermal natural convection effect, which I am trying to understand what you mean here.
Remember, the displacement was downward (against lift), not upwards during mag-on at a higher occurance over the 2000 or so data points. Your suggestion seems to imply vertical (upward) jetting which I cannot visualize in my test. The rising plume of thermals should (if I understand basic fluid dynamics) impose an upwards lift, not a downward force.
Is there something you can point me to help me understand an opposite effect of what I am thinking? i.e. a rising, thermal plume causing a downwards force?
You used a wire mesh construction in the hopes of eliminating bouyancy and jetting effects. However I believe the parts of your apparatus that do promote thermal effects are the Copper tray shapes above and below the wire mesh fustrum. It doesn't matter if the fustrum is pointed up or down, there will always be one tray that is positioned to trap hot air and supply lift. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rfmwguy on 12/18/2015 05:31 PM - Except therm vids show little heating below mag
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/18/2015 05:47 PM -
It is explained by thermal convection on a plate that is heated above the plate (by the magnetron). Convection currents are generated whereby the hotter air above the plate experiences a buoyancy force going upwards. As a result of this the plate is virtually "sucked up" experiencing a lift force and the colder air above the hot air goes downward to occupy the space previously occupied by the hotter air. This convection is time-dependent, the fluid flow is not laminar, but it involves vortices above and below the plate. Vortex shedding takes place intermittently. The lift experienced by the plate and by the hot magnetron partially open cavity (due to their own buoyancy) is a chaotic function of time (due to the nonlinear nature, time dependent nature of the Navier-Stokes equation, particularly in this low Reynolds number regime). Due to the low Reynolds number regime being above Stokes flow, in an intermediate region of the Navier-Stokes flow which is difficult to model (unless done numerically) the time dependence of the convection and vortex shedding is complicated, involving chaotic fluctuations with time. The turning ON and OFF the magnetron further complicates the time-dependent nature of these fluctuations.
The chaotic time dependence of the lift force, and its direction is not subject to intuition any more than you can intuit the time dependence and direction of lift of a wing in the region of stall, beyond the critical angle of attack. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rfmwguy on 12/18/2015 06:00 PM - The top plate is 12 square inches in case anyone wants to put solid number together
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SteveD on 12/18/2015 06:01 PM - Urm, can we establish a floor above which it becomes unlikely that a device not specifically engineered to produce thrust will be able to reach. Seems like there should be a point, on a N/kw basis where you need some kind of propeller or rocket nozzle. An efficiency beyond that point, and something is happening.
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rfmwguy on 12/18/2015 06:07 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459632#msg1459632">Quote from: SteveD on 12/18/2015 05:09 PM</a>
The transformer is in a separate box several feet away, not on the frustum. The small box on top is simple RLC circuitry, tapping the 4kV line to help power the filament. No transformers there.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459316#msg1459316">Quote from: rfmwguy on 12/18/2015 12:13 AM</a>
Unless someone demonstrates or points out a potential error source that approaches a triple-digit micronewton level, I will not chase those phantoms. Lorentz force in the horizontal axis falls into this category as does thermal plume turbulence (fluid analysis), imho. Show me a non-jet down force test result or example and I may take that off of my phantom list. There were no jets identified on the top plate emanating from the mag per my thermal scans, nor was there uneven heating of any of the outer surfaces; a clear sign of air jets.
So, statistics are most straight-forward way to analyze beam displacement variances between mag on and mag off cycles. No other error source hypothesis approaches the force level needed to interrupt the thermal lift track; Lorentz, air jets, plume turbulence, thermal expansion, etc., etc.
If anyone has other ideas...I'm all ears and will test for them if funding allows next year.
Well I had thought that the transformer hum might have vibrated the hot air trapped in the heat sink chamber, causing more of it to spill out, reducing lift. Would think that this would have shown up clearly on the thermal camera though. Best was I can think of to test for this would be simply proceeding as planned. If you remove the magnetron from the top of the thing and it goes down more with higher Q . . . well that's interesting.
I think the big problem with mangetrons are that their outputs can take a random walk. Sometimes you get very little in resonance and sometimes you get more. Statistics would seem to be an excellent way of dealing with an rf source given to random walks.
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SteveD on 12/18/2015 06:08 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459631#msg1459631">Quote from: zen-in on 12/18/2015 05:08 PM</a>
I don't believe gyroscopic precession can be used to explain Shawyer's video. The pump is not spinning fast enough for gyroscopic effects. But just having a motor mounted with its shaft parallel to the rotational axis of the apparatus is enough to start it rotating. Several years ago I mounted a motor on a rotating table. When the motor was spun up the table rotated. When the motor was switched off the table rotated back to its original position. We don't now enough about Shawyers apparatus to be able to analyze what is happening. That's why the focus has been on DIY experiments.
Hum, didn't the rotation start like 20 minutes into the test? Would think the fans on the laptop would be a more likely cause. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SeeShells on 12/18/2015 06:14 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459643#msg1459643">Quote from: rfmwguy on 12/18/2015 05:31 PM</a>
Except therm vids show little heating below mag
One thing that's important that I didn't do the first time in my post testing prior to a full scale run was monitor the spectrum of the magnetron with my Spectrum Analyzer. It can show when the magnetron powers on, reaches lock or not and even shifting out of lock during a run.
I will be doing so in the next tests because that time stamp data can be used to overlay any thrust or lack of thrust data from the digital acceleration or digital force profiles.
Shell -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rfmwguy on 12/18/2015 06:57 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459673#msg1459673">Quote from: SeeShells on 12/18/2015 06:14 PM</a>
Couple of pages back, I mentioned overlapping windows on the laptop screen with the smaller window being the spec an trace. Screen recording software can then lock these 2 together output one avi file. Worked well for me.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459643#msg1459643">Quote from: rfmwguy on 12/18/2015 05:31 PM</a>Except therm vids show little heating below mag
One thing that's important that I didn't do the first time in my post testing prior to a full scale run was monitor the spectrum of the magnetron with my Spectrum Analyzer. It can show when the magnetron powers on, reaches lock or not and even shifting out of lock during a run.
I will be doing so in the next tests because that time stamp data can be used to overlay any thrust or lack of thrust data from the digital acceleration or digital force profiles.
Shell -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Kenjee on 12/18/2015 07:05 PM -
(
)
Maybe? -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: aero on 12/18/2015 07:10 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459654#msg1459654">Quote from: Rodal on 12/18/2015 05:47 PM</a>
It is explained by thermal convection on a plate that is heated above the plate (by the magnetron). Convection currents are generated whereby the hotter air above the plate experiences a buoyancy force going upwards. As a result of this the plate is virtually "sucked up" experiencing a lift force and the colder air above the hot air goes downward to occupy the space previously occupied by the hotter air. This convection is time-dependent, the fluid flow is not laminar, but it involves vortices above and below the plate. Vortex shedding takes place intermittently. The lift experienced by the plate and by the hot magnetron partially open cavity (due to their own buoyancy) is a chaotic function of time (due to the nonlinear nature, time dependent nature of the Navier-Stokes equation, particularly in this low Reynolds number regime). Due to the low Reynolds number regime being above Stokes flow, in an intermediate region of the Navier-Stokes flow which is difficult to model (unless done numerically) the time dependence of the convection and vortex shedding is complicated, involving chaotic fluctuations with time. The turning ON and OFF the magnetron further complicates the time-dependent nature of these fluctuations.
The chaotic time dependence of the lift force, and its direction is not subject to intuition any more than you can intuit the time dependence and direction of lift of a wing in the region of stall, beyond the critical angle of attack.
Just a thought - It is well understood that turbulent flow is very difficult to model in detail. However, streamlining is a proven technique to minimize turbulence in airflow around high speed vehicles, cars and aircraft, resulting in near total laminar flow. Laminar flow is much more amenable to mathematical modelling.
Is it within the reach of a DYI'ers to construct a very low mass attachment for each end of the frustum to streamline the apparatus and thereby significantly reducing or eliminating turbulence?
@Kenjee - cross posted, we're thinking along the same lines. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/18/2015 07:26 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459708#msg1459708">Quote from: aero on 12/18/2015 07:10 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459654#msg1459654">Quote from: Rodal on 12/18/2015 05:47 PM</a>
It is explained by thermal convection on a plate that is heated above the plate (by the magnetron). Convection currents are generated whereby the hotter air above the plate experiences a buoyancy force going upwards. As a result of this the plate is virtually "sucked up" experiencing a lift force and the colder air above the hot air goes downward to occupy the space previously occupied by the hotter air. This convection is time-dependent, the fluid flow is not laminar, but it involves vortices above and below the plate. Vortex shedding takes place intermittently. The lift experienced by the plate and by the hot magnetron partially open cavity (due to their own buoyancy) is a chaotic function of time (due to the nonlinear nature, time dependent nature of the Navier-Stokes equation, particularly in this low Reynolds number regime). Due to the low Reynolds number regime being above Stokes flow, in an intermediate region of the Navier-Stokes flow which is difficult to model (unless done numerically) the time dependence of the convection and vortex shedding is complicated, involving chaotic fluctuations with time. The turning ON and OFF the magnetron further complicates the time-dependent nature of these fluctuations.
The chaotic time dependence of the lift force, and its direction is not subject to intuition any more than you can intuit the time dependence and direction of lift of a wing in the region of stall, beyond the critical angle of attack.
Just a thought - It is well understood that turbulent flow is very difficult to model in detail. However, streamlining is a proven technique to minimize turbulence in airflow around high speed vehicles, cars and aircraft, resulting in near total laminar flow. Laminar flow is much more amenable to mathematical modelling.
Is it within the reach of a DYI'ers to construct a very low mass attachment for each end of the frustum to streamline the apparatus and thereby significantly reducing or eliminating turbulence?
@Kenjee - cross posted, we're thinking along the same lines.
If people insist on using a magnetron...
Yes any of these ideas are better than the NSF-1701 test configuration (the naked magnetron on top of the plate).
Berca had it on the side of the EM Drive (that eliminates the lift from the EM Drive end-plate but still gives lift from the hot magnetron, and it is unsymmetric on Berca's case).
But even better is Shell's idea to remove the magnetron from the top of the EM Drive all together, have the magnetron far away, and feed the EM Drive with dual symmetric waveguides. Using waveguides has been the proven technique in Meep to excite TE modes.
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: X_RaY on 12/18/2015 07:40 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459702#msg1459702">Quote from: Kenjee on 12/18/2015 07:05 PM</a>
(
This would reinforce the balloon effect...)
Maybe?
I think to separate the magnetron from the cavity (like Shells design) is on of the best possibilities, especially at ambient pressure. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SeeShells on 12/18/2015 08:26 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459662#msg1459662">Quote from: SteveD on 12/18/2015 06:01 PM</a>
Urm, can we establish a floor above which it becomes unlikely that a device not specifically engineered to produce thrust will be able to reach. Seems like there should be a point, on a N/kw basis where you need some kind of propeller or rocket nozzle. An efficiency beyond that point, and something is happening.
Anything beyond the thrust of a photon rocket or on par with a ion engine is a game changer in many many ways.
But here is the kicker, we not even sure if what we're seeing is thrust, maybe masses are being changed somehow, maybe it can't accelerate, just somehow reduce mass? This is why I'm doing acceleration profiles with a moving beam and static pressure readings on the same DUT and test stand. Is there a difference? I don't honestly know.
Shell -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Possibles on 12/18/2015 09:07 PM -
Hi Guys...
Been a long time since I have posted here. The place seems to have "Thinned out" somewhat... and gotten down to grass roots. :)
Can someone put a quick summary up? Got to admit I'm a bit fearful of reading through it all. And I'm worn out.
I did have a thought though. And probably the only one that makes sense to me. And its to do with our understanding of space-time. The topic here is "Potential" and how we see it. Let me try to explain, and please remember I'm not Einstein.
Visualize for a moment a Black Hole. Mathematics breaks down beyond the event horizon, but we can still infer things. The main problem is that everything becomes indistinct. And that is EXACTLY the point. Space and Time become "Potential" They become free of the shackles that our Universe imposes on them.
There is a very interesting viewpoint I have come up with. And there is NO way of testing it. Boiling it down to the absolute core, we as humans perceiving the Universe cannot equate the concept of "Nothingness" unless we have an opposition. Our brains simply cannot and will not do that. Take the logical path of this sentence for example: "Nothingness nothings itself out of existence" It cannot exist without a human definition, so, like God in the Hitchhikers, he gives up and goes away. Because we are the human observers, and we are the problem.
Ergo, we are screwed.
Unless the Universe works the same way we do? Now that would be weird eh? Now. Im going to stop right here, as Chris might get a bit miffed with off topic stuff. And I don't want to interrupt the progress here. Im not sure what to do in this regard. (Perhaps some guidance...some pills?)
But I do believe we might just be disrupting the POTENTIAL of space-time but not space-time itself. They are two very, very different things. The former is Timeless, and the latter is that instant of creation where our Universe sprung into existence and instantly tried to spring out of it again.
We are the guys and gals stuck in that lattice of instant confusion.
I hope that wasn't too foolish.
Quick mod for clarity. You don't need black hole energies to do things like this. Maybe the best way of looking at the EmDrive is as a "Filter"
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: OnlyMe on 12/18/2015 09:08 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459809#msg1459809">Quote from: Blaine on 12/18/2015 08:48 PM</a>
Could this effect, in any way, start causing superconductivity in the copper? Is their any possible way that this could happen? I'm not thinking along the lines of Roger Shaywer. I'm think maybe if their is super conductivity then gravitons could be reflecting off the surface of the copper.
Super conductors of theirselves don't react differently to gravity than anything else.
Drop an apple and a super conductor rock and they fall at the same rate. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Blaine on 12/18/2015 09:14 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459833#msg1459833">Quote from: OnlyMe on 12/18/2015 09:08 PM</a>
Thank you for the reply. I was actually just taking an idea from this article: http://www.livescience.com/50119-superconductors-physicists-gravity-particles.html<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459809#msg1459809">Quote from: Blaine on 12/18/2015 08:48 PM</a>Could this effect, in any way, start causing superconductivity in the copper? Is their any possible way that this could happen? I'm not thinking along the lines of Roger Shaywer. I'm think maybe if their is super conductivity then gravitons could be reflecting off the surface of the copper.
Super conductors of theirselves don't react differently to gravity than anything else.
Drop an apple and a super conductor rock and they fall at the same rate.
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: glennfish on 12/18/2015 09:48 PM -
RE: calculating thermals.
Given any of the DIY designs under consideration...
Assuming resonance is the path ...
Given the magnetrons in play today, what is the easiest way to take a DIY design and just dump heat AND destroy any meaningful resonance? I have a vision of stuffing steel wool into the frustum as a first approximation, but there might be a simpler way to totally detune a frustum. Bring the Q as close to zero (one?) as possible.
To me, that would be the cheap and dirty way to get a thermal lift measurement as a baseline data set.
Then, if you tuned for optimal resonance, highest possible Q, you'd have a baseline thermal for comparison.
Critiques? Ideas? -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/18/2015 09:53 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459831#msg1459831">Quote from: Possibles on 12/18/2015 09:07 PM</a>
Hi Guys...
Been a long time since I have posted here. The place seems to have "Thinned out" somewhat... and gotten down to grass roots. :)
Can someone put a quick summary up? Got to admit I'm a bit fearful of reading through it all. And I'm worn out.
....
The last institutional published experimental report was by Tajmar at the Technische Universität Dresden in Germany.
We are waiting to hear news from NASA regarding:
1) Publication of NASA's Eagleworks EM Drive tests performed in vacuum, including discussion/analysis of thermal expansion effects and effects from forces resulting from the magnetic damper.
2) Confirmation of whether or not a new testing campaign will commence at NASA Glenn to replicate the tests at NASA Johnson (Eagleworks), and if so when are the NASA Glenn results expected to be announced/reported.
Remarkably, Yang (in China) has not published any new results for a considerable amount of time, and her last publication dealt with the considerable thermal effects on her experiments (her paper on temperature vs. time measurements throughout a heated EM Drive using embedded thermocouples).
Concerning Do-It-Yourself experiments, the last experimental report was by RFMWGUY (NSF-1701 test). We are waiting to hear from Shell on her meticulously and thoroughly designed testing program. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SteveD on 12/18/2015 10:44 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459738#msg1459738">Quote from: X_RaY on 12/18/2015 07:40 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459702#msg1459702">Quote from: Kenjee on 12/18/2015 07:05 PM</a>
(
This would reinforce the balloon effect...)
Maybe?
I think to separate the magnetron from the cavity (like Shells design) is on of the best possibilities, especially at ambient pressure.
I thought the issue was thermal effects creating the illusion of movement against lift? -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SteveD on 12/18/2015 10:55 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459778#msg1459778">Quote from: SeeShells on 12/18/2015 08:26 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459662#msg1459662">Quote from: SteveD on 12/18/2015 06:01 PM</a>
Urm, can we establish a floor above which it becomes unlikely that a device not specifically engineered to produce thrust will be able to reach. Seems like there should be a point, on a N/kw basis where you need some kind of propeller or rocket nozzle. An efficiency beyond that point, and something is happening.
Anything beyond the thrust of a photon rocket or on par with a ion engine is a game changer in many many ways.
But here is the kicker, we not even sure if what we're seeing is thrust, maybe masses are being changed somehow, maybe it can't accelerate, just somehow reduce mass? This is why I'm doing acceleration profiles with a moving beam and static pressure readings on the same DUT and test stand. Is there a difference? I don't honestly know.
Shell
Well if the thing can produce thrust at the same N/kw as a Cesna engine, then it would seem to have clear terrestrial applications even as a thermal effect.
Reduced mass shouldn't be a downward movement. If this thing really is playing with mass then I'm pretty sure the implications for physics are mind blowing. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SeeShells on 12/18/2015 11:15 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459928#msg1459928">Quote from: SteveD on 12/18/2015 10:55 PM</a>
ANY thrust or deviation from nothing happening is going to upset the apple cart SteveD.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459778#msg1459778">Quote from: SeeShells on 12/18/2015 08:26 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459662#msg1459662">Quote from: SteveD on 12/18/2015 06:01 PM</a>Urm, can we establish a floor above which it becomes unlikely that a device not specifically engineered to produce thrust will be able to reach. Seems like there should be a point, on a N/kw basis where you need some kind of propeller or rocket nozzle. An efficiency beyond that point, and something is happening.
Anything beyond the thrust of a photon rocket or on par with a ion engine is a game changer in many many ways.
But here is the kicker, we not even sure if what we're seeing is thrust, maybe masses are being changed somehow, maybe it can't accelerate, just somehow reduce mass? This is why I'm doing acceleration profiles with a moving beam and static pressure readings on the same DUT and test stand. Is there a difference? I don't honestly know.
Shell
Well if the thing can produce thrust at the same N/kw as a Cesna engine, then it would seem to have clear terrestrial applications even as a thermal effect.
Reduced mass shouldn't be a downward movement. If this thing really is playing with mass then I'm pretty sure the implications for physics are mind blowing.
Shell -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: OnlyMe on 12/18/2015 11:32 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459944#msg1459944">Quote from: SeeShells on 12/18/2015 11:15 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459928#msg1459928">Quote from: SteveD on 12/18/2015 10:55 PM</a>
ANY thrust or deviation from nothing happening is going to upset the apple cart SteveD.<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459778#msg1459778">Quote from: SeeShells on 12/18/2015 08:26 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459662#msg1459662">Quote from: SteveD on 12/18/2015 06:01 PM</a>Urm, can we establish a floor above which it becomes unlikely that a device not specifically engineered to produce thrust will be able to reach. Seems like there should be a point, on a N/kw basis where you need some kind of propeller or rocket nozzle. An efficiency beyond that point, and something is happening.
Anything beyond the thrust of a photon rocket or on par with a ion engine is a game changer in many many ways.
But here is the kicker, we not even sure if what we're seeing is thrust, maybe masses are being changed somehow, maybe it can't accelerate, just somehow reduce mass? This is why I'm doing acceleration profiles with a moving beam and static pressure readings on the same DUT and test stand. Is there a difference? I don't honestly know.
Shell
Well if the thing can produce thrust at the same N/kw as a Cesna engine, then it would seem to have clear terrestrial applications even as a thermal effect.
Reduced mass shouldn't be a downward movement. If this thing really is playing with mass then I'm pretty sure the implications for physics are mind blowing.
Shell
Well you stepped into this one... Should get ready to pick up apples? -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SteveD on 12/18/2015 11:40 PM - Well it runs a gamut. On one end you have the thing clearly moving while the accelerometers read stationary (Alcubierre Drive) and on the other you've got a new take on an electric aircraft engine. Making mass dissappear would tend towards the Alcubierre end of the spectrum.
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: oliverio on 12/18/2015 11:48 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459958#msg1459958">Quote from: SteveD on 12/18/2015 11:40 PM</a>
Well it runs a gamut. On one end you have the thing clearly moving while the accelerometers read stationary (Alcubierre Drive) and on the other you've got a new take on an electric aircraft engine. Making mass dissappear would tend towards the Alcubierre end of the spectrum.
For any object in motion, though, a reduction in its mass (ceteris paribus) would read as acceleration on an accelerometer, no spacetime bending necessary. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: R.W. Keyes on 12/18/2015 11:50 PM - Do you think there's any chance we could have a convention, or if that sounds too ambitious, meeting of people interested in emdrive-related research? I'd really like to meet some of you in person, to put a voice to the words, so to speak.
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: TheTraveller on 12/19/2015 12:16 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459883#msg1459883">Quote from: glennfish on 12/18/2015 09:48 PM</a>
RE: calculating thermals.
Given any of the DIY designs under consideration...
Assuming resonance is the path ...
Given the magnetrons in play today, what is the easiest way to take a DIY design and just dump heat AND destroy any meaningful resonance? I have a vision of stuffing steel wool into the frustum as a first approximation, but there might be a simpler way to totally detune a frustum. Bring the Q as close to zero (one?) as possible.
To me, that would be the cheap and dirty way to get a thermal lift measurement as a baseline data set.
Then, if you tuned for optimal resonance, highest possible Q, you'd have a baseline thermal for comparison.
Critiques? Ideas?
With a frustum Q of 1, very little Rf energy will enter the frustum. Almost all the energy will be reflected and will be thermalised elsewhere.
The only way to heat up the frustum is to excite it at resonance.
The higher the frustum Q, the higher the stored energy in the frustum, that will eventually be converted into heat, plus hopefully a little kinetic.
During the fill process, the frustum impedance changes quite a lot, with initially almost all the energy being reflected. The pulse length of a magnetron burst may alter the amount of energy delivered into the frustum from that burst by both freq of the burst in relationship to frustum resonance and the duration in relationship to the TC 5 fill time versus the pulse length. Frustums can be tricky beasts.
It takes 5 x TC to fill the frustum to peak energy, with 1 TC = Q unloaded / ( 2 Pi freq). 5 TC fill time for a 50k loaded Q (100k unloaded Q) frustum would be around 32 usec at 2.45 GHz.
Have started to build my 1st copper frustum. Expect data end Jan 2016. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: rfmwguy on 12/19/2015 01:03 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459961#msg1459961">Quote from: R.W. Keyes on 12/18/2015 11:50 PM</a>
Do you think there's any chance we could have a convention, or if that sounds too ambitious, meeting of people interested in emdrive-related research? I'd really like to meet some of you in person, to put a voice to the words, so to speak.
Have sponsor will travel ;) -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: Rodal on 12/19/2015 01:20 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459961#msg1459961">Quote from: R.W. Keyes on 12/18/2015 11:50 PM</a>
Do you think there's any chance we could have a convention, or if that sounds too ambitious, meeting of people interested in emdrive-related research? I'd really like to meet some of you in person, to put a voice to the words, so to speak.
That sounds like a great idea.
Would you like to meet in Las Vegas or in New York City? -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: ThereIWas3 on 12/19/2015 01:23 AM -
Google Hangouts?
-
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: OnlyMe on 12/19/2015 01:36 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1460003#msg1460003">Quote from: Rodal on 12/19/2015 01:20 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459961#msg1459961">Quote from: R.W. Keyes on 12/18/2015 11:50 PM</a>
Do you think there's any chance we could have a convention, or if that sounds too ambitious, meeting of people interested in emdrive-related research? I'd really like to meet some of you in person, to put a voice to the words, so to speak.
That sounds like a great idea.
Would you like to meet in Las Vegas or in New York City?
What's the weather like in New York? Doesn't matter in Vegas! -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: zellerium on 12/19/2015 02:15 AM -
If we meet in LA, I'll be there!
I'm curious: what would happen to the output of the magnetron if the power were reduced?
I'm wondering if reducing the power output might "clean-up" the spectrum and concentrate more of the energy within the resonance bandwidth. This might lead to less magnetron heating.
Also, is reducing the output power as simple as this guy claims?
Link: http://danyk.cz/magn2_en.html
To minimize thermal effects, is there any way to conduct more heat through the balance beam?
Or what if the frustum were insulated, and heat was conducted to radiators positioned in opposite directions that wouldn't effect thrust?
edit:
On second thought, the radiators would probably still produce convective effects. But maybe they would help to minimize the convective effects in the thrust direction.
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Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: ThereIWas3 on 12/19/2015 03:46 AM -
Reducing mass. Hmm. If you eliminate mass, you eliminate inertia. If you do that, various effects as you approach the speed of light no longer happen. The spacecraft in the E.E. Doc Smith books worked on this principle. Somehow I doubt that is what is going on here. :(
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Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: JonathanD on 12/19/2015 05:09 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1460045#msg1460045">Quote from: ThereIWas3 on 12/19/2015 03:46 AM</a>
Reducing mass. Hmm. If you eliminate mass, you eliminate inertia.
So I suck at this stuff. But in my understanding photons don't have mass, but they are influenced by gravity only because they are just traversing curved space-time in the most direct way. So photons do not have any inertia then, correct? Just making sure, sorry for the Physics 101 diversion :) -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SeeShells on 12/19/2015 05:18 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1460045#msg1460045">Quote from: ThereIWas3 on 12/19/2015 03:46 AM</a>
Reducing mass. Hmm. If you eliminate mass, you eliminate inertia. If you do that, various effects as you approach the speed of light no longer happen. The spacecraft in the E.E. Doc Smith books worked on this principle. Somehow I doubt that is what is going on here. :(
Let's see, we have copper, right?
It was a simple rhetorical statement that I simply have no clue what is going on... yet.
Shell
PS: Read them all. 8) -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: R.W. Keyes on 12/19/2015 11:08 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1460005#msg1460005">Quote from: OnlyMe on 12/19/2015 01:36 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1460003#msg1460003">Quote from: Rodal on 12/19/2015 01:20 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459961#msg1459961">Quote from: R.W. Keyes on 12/18/2015 11:50 PM</a>
Do you think there's any chance we could have a convention, or if that sounds too ambitious, meeting of people interested in emdrive-related research? I'd really like to meet some of you in person, to put a voice to the words, so to speak.
That sounds like a great idea.
Would you like to meet in Las Vegas or in New York City?
What's the weather like in New York? Doesn't matter in Vegas!
If it were up to me, I'd want it in Boston. But that's not practical. Las Vegas is probably the best place to have it. Oh, the weather? Last time I was in LV it was 112 degrees. The time before that, there was thunderstorms, and floods. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: TheTraveller on 12/19/2015 11:18 AM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1460115#msg1460115">Quote from: R.W. Keyes on 12/19/2015 11:08 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1460005#msg1460005">Quote from: OnlyMe on 12/19/2015 01:36 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1460003#msg1460003">Quote from: Rodal on 12/19/2015 01:20 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459961#msg1459961">Quote from: R.W. Keyes on 12/18/2015 11:50 PM</a>
Do you think there's any chance we could have a convention, or if that sounds too ambitious, meeting of people interested in emdrive-related research? I'd really like to meet some of you in person, to put a voice to the words, so to speak.
That sounds like a great idea.
Would you like to meet in Las Vegas or in New York City?
What's the weather like in New York? Doesn't matter in Vegas!
If it were up to me, I'd want it in Boston. But that's not practical. Las Vegas is probably the best place to have it. Oh, the weather? Last time I was in LV it was 112 degrees. The time before that, there was thunderstorms, and floods.
Always liked Caesar's Palace. Wife likes the shopping.
Make it March 2016 or later & I'll bring along my S band spherical end plate thruster on the rotary test rig. It is designed to travel.
Phil -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: R.W. Keyes on 12/19/2015 12:42 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1460120#msg1460120">Quote from: TheTraveller on 12/19/2015 11:18 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1460115#msg1460115">Quote from: R.W. Keyes on 12/19/2015 11:08 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1460005#msg1460005">Quote from: OnlyMe on 12/19/2015 01:36 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1460003#msg1460003">Quote from: Rodal on 12/19/2015 01:20 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459961#msg1459961">Quote from: R.W. Keyes on 12/18/2015 11:50 PM</a>
Do you think there's any chance we could have a convention, or if that sounds too ambitious, meeting of people interested in emdrive-related research? I'd really like to meet some of you in person, to put a voice to the words, so to speak.
That sounds like a great idea.
Would you like to meet in Las Vegas or in New York City?
What's the weather like in New York? Doesn't matter in Vegas!
If it were up to me, I'd want it in Boston. But that's not practical. Las Vegas is probably the best place to have it. Oh, the weather? Last time I was in LV it was 112 degrees. The time before that, there was thunderstorms, and floods.
Always liked Caesar's Palace. Wife likes the shopping.
Make it March 2016 or later & I'll bring along my S band spherical end plate thruster on the rotary test rig. It is designed to travel.
Phil
I liked Caesar's as well.I think March is a bit soon...these things take planning and coordination. It's not something I've done before, but I have a friend who has put on several, whom I can ask for hints.
I'd like to see actual Frustums, and put them under test with some appropriate thrust measuring devices, such as your rotary test rig.
We could have scheduled presentations, but I am wary of too much structure.
Thoughts on this?
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Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: OnlyMe on 12/19/2015 12:52 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1460120#msg1460120">Quote from: TheTraveller on 12/19/2015 11:18 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1460115#msg1460115">Quote from: R.W. Keyes on 12/19/2015 11:08 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1460005#msg1460005">Quote from: OnlyMe on 12/19/2015 01:36 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1460003#msg1460003">Quote from: Rodal on 12/19/2015 01:20 AM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459961#msg1459961">Quote from: R.W. Keyes on 12/18/2015 11:50 PM</a>
Do you think there's any chance we could have a convention, or if that sounds too ambitious, meeting of people interested in emdrive-related research? I'd really like to meet some of you in person, to put a voice to the words, so to speak.
That sounds like a great idea.
Would you like to meet in Las Vegas or in New York City?
What's the weather like in New York? Doesn't matter in Vegas!
If it were up to me, I'd want it in Boston. But that's not practical. Las Vegas is probably the best place to have it. Oh, the weather? Last time I was in LV it was 112 degrees. The time before that, there was thunderstorms, and floods.
Always liked Caesar's Palace. Wife likes the shopping.
Make it March 2016 or later & I'll bring along my S band spherical end plate thruster on the rotary test rig. It is designed to travel.
Phil
I am not far from Vegas here in SoCal, but barring someone actually showing up with a functional.., even marginally functional EMDrive, I would more likely forgo the trip and just put the money into someone's efforts...
The weather in Vegas is seldom an issue, no matter what it is. Most of the time you wouldn't even know what time of day it is.
Another thing, it might be possible to get a group rate.., if there were enough notice and a drive that could be displayed working at one of the casinos. -
Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: OnlyMe on 12/19/2015 01:41 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1460017#msg1460017">Quote from: zellerium on 12/19/2015 02:15 AM</a>
If we meet in LA, I'll be there!
I'm curious: what would happen to the output of the magnetron if the power were reduced?
I'm wondering if reducing the power output might "clean-up" the spectrum and concentrate more of the energy within the resonance bandwidth. This might lead to less magnetron heating.
Also, is reducing the output power as simple as this guy claims?
Link: http://danyk.cz/magn2_en.html
To minimize thermal effects, is there any way to conduct more heat through the balance beam?
Or what if the frustum were insulated, and heat was conducted to radiators positioned in opposite directions that wouldn't effect thrust?
edit:
On second thought, the radiators would probably still produce convective effects. But maybe they would help to minimize the convective effects in the thrust direction.
Yang provided the following in her 2013 paper,
"the practical maximum microwave output power is 13 W, 120 W, 85 W, 65 W, 45 W, and 48 W respectively at the nominal output power 200 W, 300 W, 400 W, 500 W, 600 W, and 700 W."
The graph at the link below uses the nominal output power and extends that all of the way to Yangs maximum of 2500 watts. But if you were to use the practical maximum output from the above it would look a bit different... And might suggest that she was getting a better percentage of practical microwave output at the higher nominal powers.
http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=39004.0;attach=1087396
I expect that much of that would depend on the magnetron and exactly what frequencies you are trying to lock resonance at..., and how you are trying to control the magnetron output.... Not enough detail on any of that...
... I believe Shell has or is in the process of addressing some of the heat issues you raise. Her magnetron is located remotely from the frustum and her balance beam is non metallic, I think it was a carbon fiber of some sort, with lower thermal expansion.
Magnetrons seem to be a dirty power source for the frustum, but they are the cheap and readily accessible starting point... They are also what Yang and Shawyer were using to make their claims. Ultimately, unless the fact that they are a dirty source is part of what generates the effect, I suspect that a cleaner microwave source like a tunable signal generator and amplifier, or maybe even eventually a fully solid state microwave source, either of which could provide a cleaner signal, at a far greater expense, would be the next step and reduce some of the heat issues.
I think there has been mention back in Thread 5 about the possibility of using a used or surplus signal generaotor/amp system, with a couple of links to sources for used equipement. Budgets and a need for some practical experience with the designs stand in the way of jumping right into that kind of setup and expense.
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Title: Re: EM Drive Developments - related to space flight applications - Thread 6
Post by: SeeShells on 12/19/2015 03:12 PM -
<a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1460156#msg1460156">Quote from: OnlyMe on 12/19/2015 01:41 PM</a><a href="http://forum.nasaspaceflight.com/index.php?topic=39004.msg1460017#msg1460017">Quote from: zellerium on 12/19/2015 02:15 AM</a>
If we meet in LA, I'll be there!
I'm curious: what would happen to the output of the magnetron if the power were reduced?
I'm wondering if reducing the power output might "clean-up" the spectrum and concentrate more of the energy within the resonance bandwidth. This might lead to less magnetron heating.
Also, is reducing the output power as simple as this guy claims?
Link: http://danyk.cz/magn2_en.html
To minimize thermal effects, is there any way to conduct more heat through the balance beam?
Or what if the frustum were insulated, and heat was conducted to radiators positioned in opposite directions that wouldn't effect thrust?
edit:
On second thought, the radiators would probably still produce convective effects. But maybe they would help to minimize the convective effects in the thrust direction.
Yang provided the following in her 2013 paper,
"the practical maximum microwave output power is 13 W, 120 W, 85 W, 65 W, 45 W, and 48 W respectively at the nominal output power 200 W, 300 W, 400 W, 500 W, 600 W, and 700 W."
The graph at the link below uses the nominal output power and extends that all of the way to Yangs maximum of 2500 watts. But if you were to use the practical maximum output from the above it would look a bit different... And might suggest that she was getting a better percentage of practical microwave output at the higher nominal powers.
http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=39004.0;attach=1087396
I expect that much of that would depend on the magnetron and exactly what frequencies you are trying to lock resonance at..., and how you are trying to control the magnetron output.... Not enough detail on any of that...
... I believe Shell has or is in the process of addressing some of the heat issues you raise. Her magnetron is located remotely from the frustum and her balance beam is non metallic, I think it was a carbon fiber of some sort, with lower thermal expansion.
Magnetrons seem to be a dirty power source for the frustum, but they are the cheap and readily accessible starting point... They are also what Yang and Shawyer were using to make their claims. Ultimately, unless the fact that they are a dirty source is part of what generates the effect, I suspect that a cleaner microwave source like a tunable signal generator and amplifier, or maybe even eventually a fully solid state mi
