EM Drive - User contributions [en]

Useful EMDrive Design and Test Tools

2015-08-22T21:31:02Z

Flux capacitor: New version of the picture explaining how to use the spreadsheet

== Simulations ==

See details of using [[MEEP]] for simulations.

== Roger Shawyer's EMDrive Design ==

TheTraveller's [https://www.dropbox.com/s/u6v90c5yb050u52/EMDriveCalc20150809a.xlsx?dl=1 EMDrive design tool] (last updated 8/11/15), developed in cooperation with Roger Shawyer.

[[File:how_to_use_the_spreadsheet.png]]

* '''Testing an EMDrive''' <ref>[http://www.emdrive.com/EmDriveForceMeasurement.pdf Measuring Thrust of an EmDrive]</ref>

Shawyer ''claims'' to have successfully measured EMDrive thrust by:

'''1) Using a scale directly under or offset to one side of the EMDrive.'''

[[File:ShawyerOffsetScale.jpg]]

'''2) Using an overhead spring to offset some of the EMDrive weight on a scale under the EmDrive.'''

[[File:ShawyerSpringOverAScale.jpg]]

'''3) Using a knife edge Teeter Totter Balance Beam.'''

[[File:ShawyerBalanceBeam.jpg]]

'''4) Using a rotary air bearing setup to directly measure acceleration and deceleration.'''

[[File:ShawyerRotaryTestRig.jpg]]

None of Shawyer's publications have been ever published in peer-reviewed journals. What Shawyer claims to be EM Drive force measurements could be the result of experimental artifacts. According to the scientific method, replication of his experiments need to be performed at many scientific institutions to confirm or nullify his claims.

== References ==

File:How to use the spreadsheet.png

2015-08-22T21:29:09Z

Flux capacitor: Flux capacitor uploaded a new version of File:How to use the spreadsheet.png

File:How to use the spreadsheet.png

2015-08-22T21:20:40Z

Flux capacitor:

Useful EMDrive Design and Test Tools

2015-08-22T20:31:42Z

Flux capacitor: working link replacing broken one

== Simulations ==

See details of using [[MEEP]] for simulations.

== Roger Shawyer's EMDrive Design ==

TheTraveller's [https://www.dropbox.com/s/u6v90c5yb050u52/EMDriveCalc20150809a.xlsx?dl=1 EMDrive design tool] (last updated 8/11/15), developed in cooperation with Roger Shawyer.

[[File:SSSmall.jpg]]

* '''Testing an EMDrive''' <ref>[http://www.emdrive.com/EmDriveForceMeasurement.pdf Measuring Thrust of an EmDrive]</ref>

Shawyer ''claims'' to have successfully measured EMDrive thrust by:

'''1) Using a scale directly under or offset to one side of the EMDrive.'''

[[File:ShawyerOffsetScale.jpg]]

'''2) Using an overhead spring to offset some of the EMDrive weight on a scale under the EmDrive.'''

[[File:ShawyerSpringOverAScale.jpg]]

'''3) Using a knife edge Teeter Totter Balance Beam.'''

[[File:ShawyerBalanceBeam.jpg]]

'''4) Using a rotary air bearing setup to directly measure acceleration and deceleration.'''

[[File:ShawyerRotaryTestRig.jpg]]

None of Shawyer's publications have been ever published in peer-reviewed journals. What Shawyer claims to be EM Drive force measurements could be the result of experimental artifacts. According to the scientific method, replication of his experiments need to be performed at many scientific institutions to confirm or nullify his claims.

== References ==

Evanescent waves

2015-08-09T21:02:15Z

Flux capacitor: Link to Zneg and Fan paper

Two different evanescent wave theories have been proposed at NSF, one for evanescent waves leaking to the exterior of the EM Drive and one for evanescent waves strictly confined to its interior:

@Aero first proposed that evanescent waves ''leaked'' from the interior of the EM Drive through small gaps and produced an ''external'' evanescent wave near-field. @Aero studied (with a MEEP 2-D model) the interaction of these evanescent waves with the environment around the EM Drive, for example the stainless steel vacuum chamber at NASA Eagleworks. Shortly after this, Paul March reported at NSF conducting a test at NASA Eagleworks with the EM Drive outside the stainless steel vacuum chamber that exhibited measured thrust and thus may have nullified this hypothesis (several tests conducted by R. Shawyer and by Prof. Juan Yang may have also been conducted in environments were such interaction may have been nullified). @Aero also proposed another hypothesis involving evanescent waves and tachyons (hypothetical particles travelling faster than photons).

Later Desiato (@WarpTech) and Rodal proposed at the NSF forum that the EmDrive's tapered conical design causes a gradient in the electromagnetic field such that travelling waves (from the RF source) propagating towards the small end of the truncated cone are attenuated by the tapering geometry, producing evanescent waves that carry momentum. The EM Drive must then accelerate to satisfy conservation of momentum. The standing waves inside the EM Drive (responsible for the high Q resonance) are comprised of travelling waves propagating in opposite directions. (How the evanescent waves travelling toward the small end may benefit from the high Q stored energy density from the standing waves remains to be analyzed.) <ref>[http://forum.nasaspaceflight.com/index.php?topic=37642.msg1382031#msg1382031 Forum post by Rodal]</ref>

== Status ==

== Numerical Analysis==

@Aero performed calculations for evanescent waves leaking from the EM Drive and producing an external near-field. He used a two-dimensional MEEP Finite Difference model that modeled the EM Drive truncated cone as a flat trapezium. Maxwell's equations were solved in the 2-D domain, thus the transverse electromagnetic vector could only be represented as a scalar. The 2-D model was due to the enormous amount of memory and computer time required by the Finite Difference method, which made a 3-D model in a home PC impractical. The results from the 2-D analysis showed a thrust force/input-power multiple of 2-3 times that of a perfectly collimated photon drive, which is significantly beneath the reported measurements of EM Drive by NASA Eagleworks, Shawyer's SPR and Prof. Juan Yang's team at NWPU.<ref>[http://forum.nasaspaceflight.com/index.php?topic=36313.msg1313876#msg1313876 Initial calculations by aero.]</ref>

Utilizing [http://ab-initio.mit.edu/wiki/index.php/Meep MEEP] 2-D model, the conclusion was that due to rapid dropoff at the frustum surface, evanescent waves were of insufficient magnitude to explain the observed thrust.<ref>[http://forum.nasaspaceflight.com/index.php?topic=36313.msg1330521#msg1330521 this post by @aero on modeled evanescent waves]</ref>. See details about @aero's [http://forum.nasaspaceflight.com/index.php?topic=37642.msg1382078#msg1382078 MEEP control file].

== Relevant Papers ==

* [https://www.osapublishing.org/view_article.cfm?gotourl=https%3A%2F%2Fwww%2Eosapublishing%2Eorg%2FDirectPDFAccess%2FCAAD3BE7%2DB96D%2D5276%2D041FDBDB0A54A3B5%5F175583%2Foe%2D17%2D1%2D34%2Epdf%3Fda%3D1%26id%3D175583%26seq%3D0%26mobile%3Dno&org= "Electromagnetic fields and transmission properties in tapered hollow metallic waveguides"] by Xiahui Zeng and Dianyuan Fan. Optics Express Vol. 17, Issue 1, pp. 34-45 (2009) •doi: 10.1364/OE.17.000034
* [http://arxiv.org/pdf/1308.0547.pdf "Extraordinary momentum and spin in evanescent waves"] by Konstantin Y. Bliokh, Aleksandr Y. Bekshaev, and Franco Nori - See Supplementary Table 1.
* https://en.wikipedia.org/wiki/Mie_scattering
* http://thermopedia.com/content/137/
* http://www.orc.soton.ac.uk/publications/theses/1460T_lnn/1460T_lnn_03.pdf
* [http://arxiv.org/pdf/0712.0347.pdf "Superluminal propagation of evanescent modes as a quantum effect"] by Zhi-Yong Wang, Cai-Dong Xiong, Bing He.
* http://wwwsis.lnf.infn.it/pub/INFN-FM-00-04.pdf - I like Appendix B
* http://arxiv.org/pdf/1211.0530v2.pdf - This one just hints at our situation.
* http://bit.ly/1Ja6QLV - Again, hints
* http://tuttle.merc.iastate.edu/ee439/topics/tunneling.pdf - Tunneling and evanescent wave math are very similar.
* http://en.wikipedia.org/wiki/Maxwell_stress_tensor - Not quite sure why this is here, maybe the stress-energy tensor derivation?

== References ==
<references />

Useful EMDrive Design and Test Tools

2015-08-09T14:45:49Z

Flux capacitor: Link to updated spreadsheet

== Simulations ==

See details of using [[MEEP]] for simulations.

== Roger Shawyer's EMDrive Design ==

TheTraveller's [https://drive.google.com/file/d/0B7kgKijo-p0iNjlZSmtuMHBzY28/view?usp=sharing Excel-based EMDrive design tool], developed in cooperation with Roger Shawyer.

[[File:SSSmall.jpg]]

* '''Testing an EMDrive''' <ref>[http://www.emdrive.com/EmDriveForceMeasurement.pdf Measuring Thrust of an EmDrive]</ref>

Shawyer ''claims'' to have successfully measured EMDrive thrust by:

'''1) Using a scale directly under or offset to one side of the EMDrive.'''

[[File:ShawyerOffsetScale.jpg]]

'''2) Using an overhead spring to offset some of the EMDrive weight on a scale under the EmDrive.'''

[[File:ShawyerSpringOverAScale.jpg]]

'''3) Using a knife edge Teeter Totter Balance Beam.'''

[[File:ShawyerBalanceBeam.jpg]]

'''4) Using a rotary air bearing setup to directly measure acceleration and deceleration.'''

[[File:ShawyerRotaryTestRig.jpg]]

None of Shawyer's publications have been ever published in peer-reviewed journals. What Shawyer claims to be EM Drive force measurements could be the result of experimental artifacts. According to the scientific method, replication of his experiments need to be performed at many scientific institutions to confirm or nullify his claims.

== References ==

Building

2015-07-01T21:07:17Z

Flux capacitor: Found the original post

This page will collect any photos, plans, and instructions for do-it-yourselfers. Efforts with enough documentation will be provided their own pages.

# [[Mulletron's Build]]
# Kurt Zeller (@zellerium) and Brian Kraft from Cal Poly are starting a build as well, using a constant cross-section cavity containing a polymer dielectric.<ref>[https://forum.nasaspaceflight.com/index.php?topic=36313.msg1368153#msg1368153 Forum post by @zellerium]</ref>
# @DIYFan - TBD
# [[@Notsosureofit is planning testing with a Gunn diode]].<ref>[http://forum.nasaspaceflight.com/index.php?topic=36313.msg1336344#msg1336344 Forum post by @Notsosureofit]</ref>
# [[TheTraveller]]
# [[Iulian Berca|@Iulian Berca]]<ref>[http://forum.nasaspaceflight.com/index.php?topic=36313.msg1371164#msg1371164 Forum post by @Iulian Berca]</ref> - Fabricated a drive in May 2015 and was posting videos at [http://www.masinaelectrica.com/emdrive-independent-test/ his website]. In [https://www.youtube.com/watch?v=Rbf7735o3hQ Test 3] he reported a force measurement toward "the small end" and later a smaller measurement in the [https://www.youtube.com/watch?v=KAMttfMC8PI reverse orientation in test 3.1]. As of 5/21/15 the magnitude and significance of these measurements were discussed on the [http://forum.nasaspaceflight.com/index.php?topic=36313.msg1377695#msg1377695 NSF forum].
# @SeeShells plans to build a hexagonal frustum out of copper mesh. The small end plate will be adjustable via a stepper motor.<ref>[http://forum.nasaspaceflight.com/index.php?topic=37642.msg1385165#msg1385165 Forum post by @SeeShells]</ref>
# @R. W. Keyes / Andromeda Research - high power, 1-20KW magnetron, superconductor Magnesium diboride on silicon carbide, to start summer 2015
# [[hackaday.io project|@movax (Paul Kocyla) and Jo Hinchliffe]]<ref>[http://forum.nasaspaceflight.com/index.php?topic=36313.msg1372073#msg1372073 Forum post by Hackaday.io]</ref> - Building the original 2.45 GHz thruster according to the Chinese paper and their own 24 GHz design simultaneously, with estimated completion date of July 2015. See [https://hackaday.io/project/5596-em-drive Hackaday project] for more details, as well as [http://n-o-d-e.net/post/119343131451/building-a-diy-emdrive an interview with Paul].
# Dave (@rmfwguy) plans to use a wifi band exciter board as Rf source, wifi booster amp, copper mesh for the frustum body, and no dielectric in the frustum.<ref>[http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=37642.0;attach=978733 @rfmwguy's updated test paper on NasaSpaceFlight forum, now includes bill of materials] </ref>. Starting in July 2015, this will be live-streamed on [http://www.ustream.tv/channel/em-drive-experiment Ustream].<ref>[http://forum.nasaspaceflight.com/index.php?topic=37642.msg1390220#msg1390220 Post by @rfmwguy]</ref>
# @DrBagelBites posted on reddit that he was planning on starting a build <ref>[https://www.reddit.com/r/EmDrive/comments/38q7m9/going_to_build_an_emdrive_update/ Post by @DrBagelBites on reddit]</ref> and provided a PDF <ref>[https://drive.google.com/file/d/0BzttGV8gaI61MGIwZUF6clh5TjA/view?pli=1 PDF by Ian Lasky on Google Drive]</ref>
# @kml Testing a non-tapered rectangular waveguide with various dielectrics inserted at one end.<ref>[http://forum.nasaspaceflight.com/index.php?topic=37642.msg1380174#msg1380174 post by @kml]</ref>

If anyone is missing, please add them here.

== Modelling ==
@phaseshift has built a SketchUp model<ref>[http://forum.nasaspaceflight.com/index.php?topic=37642.msg1380107#msg1380107 post by @phaseshift]</ref> ([[File:EM_Thruster.skp]]) of a frustum based on the estimated Shawyer Flight Thruster dimensions.

@TheTraveller constructed a [http://s000.tinyupload.com/index.php?file_id=91209150771293536709 EMDrive Calculator spreadsheet] to model thrust given various design parameters.<ref>[http://forum.nasaspaceflight.com/index.php?topic=37642.msg1382349#msg1382349 Forum post by @TheTraveller]</ref> This model was built with some input from Roger Shawyer directly.

== References ==
<references />