My understanding, and I could be wrong, is that the thrust Shawyer calculates and measures from his devices is several orders of magnitude higher than what could be obtained from photon radiation recoil - even if all of the generated RF were radiated unidirectionally. A small leak of RF would provide an undetectable thrust. That's what makes his devices interesting.
Other notes ... superconductors have been discussed for their effects on Shawyer cavities. One thing that can be said is that in space, if shielded from the sun, getting stuff really cold is not a problem. Also, superconductors (even Type I) have a finite RF resistance and so don't produce infinite Q cavities. Ordinary conductors like Cu and Ag have their surface resistance continuously declining with temperature, extrapolated to 0 resistance at 0K. For *RF* purposes, just cold copper is approaching the performance of a Type 1 superconductor at the low temperatures that would be needed for Type I superconductivity. But, Cu and Ag have the advantage that they do not have a critical temperature where everything falls apart. As I recall, the Shawyer thrust is proportional to cavity Q and power. If the Q of the cavity goes up because of cold temperature improvement in the resistivity of the cavity metal in space, the thrust will go up too. On Tue, Mar 15, 2016 at 9:41 AM, Eric Walker <eric.wal...@gmail.com> wrote: > On Tue, Mar 15, 2016 at 10:24 AM, David Roberson <dlrober...@aol.com> > wrote: > > I would assume that the guys working on these devices have the expertise >> to ensure that a very minimum amount of RF is escaping from their shielded >> cavity. This is not too difficult to achieve in real life with highly >> conductive cavities. >> > > What if ensuring that a minimum of RF escaped made the thrust go away, and > it was found that RF in the radio and infrared was benign and correlated > with the thrust? > > >> Also, the actual thrust due to photons being emitted is extremely tiny >> due to their low mass when compared to the overall device. >> > > The common understanding is that photons have no mass at all. But it is > easy to see how they can carry significant momentum in the case of the > recoil of an atom when a gamma photon is emitted during a transition from > an excited state. Radio and infrared photons do not have this kind of > momentum. But perhaps if you have a high intensity, and the beam is > focused, there will be some thrust. Has anyone attempted to measure the > thrust from a powerful flashlight, one wonders. > > Eric > >
