Please read Prof Yang's 2013 paper as attached for the electrodynamics equations that model the Forces generated on the side walls and end plates of a frustum with flat end plates. For spherical end plates, you should be able to virtually eliminate the side wall radiation pressure and generated Force reductions as per Roger's statement below.



As for what happens inside the frustum when you introduce vertex radiused end plates please refer to any of the graphics of such a frustum configuration as posted here. I have attached one such example produced by meep. A stated by Roger in his peer reviewed paper, this frustum configuration virtually eliminates radiation pressure on the side walls. Please note that this effect ONLY HAPPENS when the frustum has vertex radiused end plates.



If you wish I can easily show other examples that show flat end plates generate planar waves and spherical end plates generate spherical waves.



I do apologise for my crude drawing (lowest attachment) where I attempted to explain this effect of frustum vertex radiused spherical end plates on the Em wave fronts. It seems you may have read more into that diagram than I intended. I will not be using it anymore. Instead I will be using the meep example, which shows the effect so much better than my drawing.



I do ask you to note the modified meep image also shows the increasing guide wavelength toward the small end and the reducing guide wavelength toward the big end which drive the changes in the EM wave momentum. Exactly as Roger's theory predicts. Nice job Aero and Shell. I'm sure Roger is pleased.



The first issue with Yang's paper I can find is that Yang apparently struggles with addition and subtraction. Based on the graphs, in that paper for 200 W, they calculated forces of : 500 mN on the large plate, 270 mN on the small plate, and 520 mN on the side walls (in their normal direction). The final graph uses claims a net thrust of around 260 mN towards the small plateThe large plate minus the small plate is 230 mN before accounting for the sidewalls. If the sidewalls are at an angle of asin(230/520) or about 26 degrees, there is zero net force. (note I am using the angle of the sidewall from the axis of rotation). I can't find the actual angle in the paper, but this is seems more accurate than the 70 degrees required for their final graph to be consistent. The 26 degrees seems pretty consistent with the sketches they have.Their data contradicts their previous claim and your claim of low force on the sidewalls. It also contradicts the idea of significantly more force on the small plate than the large one. Link to post where I attached their previous claim, which also demonstrates a failure of using basic logic. You are displaying a lot of confirmation bias here, the picture does not support your claims. First, you are looking at a node in a standing wave, and claiming it is a wavefront. There is not a direct correlation between this and the directions of the underlying waves.Even if it was meaningful, there is no reason to then not look at the other surfaces that represent nodes of the standing wave. You will note that these are roughly orthogonal to the node surface you pointed out. Also, the distance between these surfaces (which you seem to be calling the "guide wavelength") decreases near the small end. (Again this paragraph is irrelevant is you understand the previous one, I am just reinforcing the point that looking at the nodes of the standing wave is not relevant in a straightforward way for understanding the motion of the underlying travelling waves, which are moving in different directions.)Traveller, you seem to be having trouble understanding the situation, so allow me to summarize:Shawyer has a hypothesis that he claims derives from standard EM theory. Me and others have pointed out multiple issues with his calculations. Only one issue is enough to sink his claims, so you even if you defend against one of the issues, the others still stand.On the other hand, the result of a lack of net force from EM theory has been demonstrated. If you manage to find multiple issues with those claims, then all of them would have to be defended against. So far, the only meaningful argument I have seen you put forth against these calculations is that it didn't account for momentum differences at different parts of the field, to which I pointed out that they used the definition of momentum stored in the fields, so your claim is incorrect.A partial summary of issues with Shawyer's (and your) claims:1. He uses results from a cylindrical waveguide for a conical resonator. Even if they do apply, a lot of math would be needed to demonstrate it.2. He claims low to no thrust on the sidewalls, This is demonstrably false (Egan's calculations) and even Yang shows large forces on the sidewalls. It demonstrates a fundamental failure to understand how the waves are propagating in the cavity.2.a. This claim combined with the (possibly correct) claim that the momentum in the fields changes from one end of the guide to the other contradicts conservation of momentum. This is because in order for the momentum in the fields to change, it would have to be transferred elsewhere (transferring momentum = applying a force), and the only other thing the waves could interact with is the sidewalls.3. He claims that the EM drive obeys conservation of momentum, and at the same time accelerates its center of energy without interacting with the external world. This is the definition of not obeying conservation of momentum.3.a. To show this he uses the special relativity velocity transformation in a completely incorrect way, and doesn't notice the issue where he creates a preferred reference frame, when the entire principle behind special relativity is that there aren't preferred reference frames.(Note this list is specifically in reference to Shawyer's claims, and most theories here bypass these issues, generally by suggesting a way that momentum is transferred elsewhere)As others have said, it is in your best interest to stop promoting theories that are clearly wrong. If you continue to make these claims it undermines your credibility, and will make people doubt any experiment that you perform. Unless you demonstrate a better understanding of physics even a rotary table demonstrator won't mean much, since angular momentum can be good at hiding and behaves non-intuitively if you aren't used to working with it.Doing an experiment and saying "I have no idea why this works" is many times better than doing an experiment and saying "this works because 1+1 = 3"