Frequently Asked Questions
- What are the experimental results regarding the EM Drives?
- See Experimental Results.
- Does the EM Drive violate momentum- or energy-conservation?
- See Energy Conservation and Momentum Conservation.
- How does an EM Drive work?
- This a graph showing how R. Shawyer describes the operation of the EM Drive.
deltaMass has shown that Shawyer does not even understand that momentum is governed by the phase velocity, not the group velocity. Therefore any explanations for thrust (like Shawyer's) which are based on a difference between group velocities, are just plain wrong.
deltaMass' assumption is just plain wrong as inside a waveguide, phase velocity is above c and momentum is governed by the group velocity or the guide waveguide:
Additionally Cullen has shown the reflection force generated on an endplate inside a waveguide is related to the guide wavelength or group velocity and not the phase velocity as claimed by deltaMass.
The researchers at NWPU also agree with the Cullen 15 equation and use it in their own calculations.
The EM Drive researchers at NASA Eagleworks and Prof. Yang's team at Northwestern Polytechnical University (NWPU) in Xi'anin, China, have different theories of its operation:
See the Theory page for a list of additional theories purporting to explain how the EmDrive works.