[Snip] > The only way that the thrust could vary with velocity would be if it > depends on velocity through a material or velocity through a field of > some kind.[end snip]
What if it only "shields" vacuum flux such that inside the cavity appears relativistically to have a higher ratio of short to long vacuum flux than outside the cavity- effectively dragging the cavity behind the Present in seeming opposition to the ambient gravitational axis. So that relative motion of the local g field through the cavity might indeed determine the thrust as a proportion of the ambient field? Best Regards Fran -----Original Message----- From: Horace Heffner [mailto:hheff...@mtaonline.net] Sent: Wednesday, November 04, 2009 12:51 AM To: vortex-l@eskimo.com Subject: Re: [Vo]:Reactionless drive claim: Emdrive On Nov 3, 2009, at 7:59 PM, Abd ul-Rahman Lomax wrote: > At 07:01 PM 11/3/2009, Horace Heffner wrote: > >> The model by which the device is said to work looks bogus. I think if >> they knew why and how it actually works they could produce a much >> better W/a ratio. The device applies force to vacuum elements. >> Their theory predicts a change in acceleration with velocity. I think >> this is nonsense. Either the device doesn't work at all in space or >> its thrust, as perceived by the occupants, does not vary with >> velocity. > > The only way that the thrust could vary with velocity would be if > it depends on velocity through a material or velocity through a > field of some kind. I didn't make the claims. See: http://www.emdrive.com/theorypaper9-4.pdf for the theory, http://www.emdrive.com/ for the company. They show a curve of acceleration vs velocity. It has nothing to do with anything external. Therefore I think it is bogus. I've done enough work in this area to believe it is possible to couple to vacuum inertia though, and that means the possibility of reactionless EM drives. > > >> A 1 g device should be able to accelerate right on beyond c, and thus >> go anywhere in the universe. > >> The occupants would feel the 1 g >> acceleration though, and that is a good thing. >> >> The time to light speed T2 at 1 g is: >> >> T2 = c/g = 3.057x10^7 s = 0.968735 years = about 11 months 20 days > > Eh? No, "g" is a measure of acceleration, Well duh. > but the acceleration produced in a reference frame by a constant > force reduces as the velocity approaches c, while, at the same > time, that acceleration is experienced as the same by the occupants > of the ship, who are now experiencing time dilation and the other > nifty effects of approaching light speed. They never get to light > speed, just closer and closer and closer. The accumulated potential > energy keeps rising. I'm totally familiar with that pablum. You don't understand. This is from the reference frame of the ship, which accelerates at a constant rate g, from the passenger point of view, with no reaction mass. We have v = a*t, so t = v/a = c/g from their point of view. > >> I have no idea what this might mean in terms of what would happen if >> they should hit some atoms along the way though, as the atom apparent >> mass might be infinite. Also, the mass presented to the incoming >> atoms would be infinite. A practical case of the irresistible force >> and the immovable object paradox? > > They would become more and more irresistible, but, unfortunately, > so would anything they hit as their velocity approaches c, and with > time dilation, they will cover a lot of space in cross-section > where there might be something. In any case, the fuel that must be > consumed to continue to accelerate like that .... how big are they, > including fuel? Read the reference if you have any serious interest. The emdrive.com page has a branch to a theory page and FAQ I think. > And then how much force is exerted by the drive? The bigger they > are the lower the acceleration for a constant fuel consumption... > Getting significant mass close to c ... forget about it. Not in the passenger reference frame. They experience constant acceleration. It is the universe that starts acting weird from their perspective. > > Ah, I wasted a few perfectly good minutes on this. This is actually a valid line of inquiry. There is a fun book on the subject, titled "Unconventional Flying Objects, a scientific analysis", Paul Hill, ISBN 1-57174-027-9. Paul Hill was an ex NASA Scientist. The book is forwarded by Edgar Mitchell, Apollo 14 Astronaut. Best regards, Horace Heffner http://www.mtaonline.net/~hheffner/
