Pilot Wave theory suggests Trumpet shaped
Emdrive would have more thrust:
"Researchers José Croca and Paulo Castro from the Centre for Philosophy of Sciences of
the University of Lisbon in Portugal suggest that not only could pilot wave theory explain
the mysterious behavior of the EM drive, it could help to make it even more powerful.
Applying a pilot wave theory to NASA’s EM drive frustum [or cone] could explain its
thrust without involving any external action applied to the system, as Newton’s third law
would require."
See:
https://www.nextbigfuture.com/2017/1...re-thrust.html