Would like to thank everyone for such diversified input on this since I have been silently following this topic since "thread one". Personally, I have a deep respect for each persons current thoughts on this.While I do realize that this is "Way out there!".Is it possible that whatever reactions/movements AKA "Thrust" could be being caused by the inverse of what's being done to slow down atoms using frequencies of light Atomic telescope brings atoms to standstill by using microwave frequencies to excite virtual particles, dark matter or even dark energy?I ask because this also seems to at least potentially show a classical to quantum transition taking place in some form. Unless it turns out that all prior experiments have had the same non discovered faults/flaws inside and outside a vacuum. Don
Quote from: Notsosureofit on 05/25/2015 07:29 pm@WarpTech raises a very good point. Any system which provides propellant-less acceleration should also work as an accelerometer. Photon resonators are already used as accelerometers. (and by extension, gravity wave detectors)Exactly, that's where Dr. McCulloch's work comes in, though I'm not well versed in his model yet. Accelerating a cavity full of energy, oscillating in modes will cause a doppler shift to propagate through. Here, that doppler shift is being caused by energy lost to the cavity.Momentum is being input to the cavity via the microwaves, dp_in/dt, and is stored in the oscillating modes, Q*dp_in/dt. The rate of dissipation of that momentum, -dp/dt = F, will determine the forces on each surface. If that rate is not simply a constant of the metal, but a variable of the geometry, there will be asymmetrical forces, velocities and doppler shifts. Agreed? Todd
@WarpTech raises a very good point. Any system which provides propellant-less acceleration should also work as an accelerometer. Photon resonators are already used as accelerometers. (and by extension, gravity wave detectors)
I did some more investigation into this paper by Yang Juan published 2014-01-09:http://wulixb.iphy.ac.cn/EN/abstract/abstract60316.shtml... It appears they use the aperture to minimize return loss and improve the Q by narrowing the bandwidth. [They still maintain that a higher Q factor in the frustum is more desirable. ]
...I think Yang is getting much better thrust values because she isn't sending the energy through coaxial cables and antennas as done by Shawyer. Maybe this allows the whole system to resonate together whereas the antennas and cables have some associated impedance and attenuation that increase losses.
...So now I'm thinking we should try to create a very thick cavity, we could forge one using aluminum pretty easily and clean it up with a CNC. [backyard casting: url:youtube.com/watch?v=sGr_XoFTKmc]
...Kurt
You should stick with Copper sheet. Cast Aluminum, even if it is pure Al will not have as good conductivity due to microcracks, slag inclusions, bubbles, etc. Aluminum is not forged because it cracks when heated and hit with hammers. A fine Silver cavity would have a higher Q than Copper, and would be much easier to form. Since there is not as much markup on Silver the cost would be about 5X the cost of Copper. A fusion weld can be done to close the cone with no discontinuity at the seam. For Copper you can get the cone crimped at the ends and use Be-Cu finger stock to bridge the flat ends (instead of solder) and adjustable slug with the cone. That would make it easy to disassemble. Later, when all is said and done it will make a good museum display.
Wiki/FAQ Threadhttp://emdrive.echothis.com/Main_PageCreated by R.W._KeyesCan this get added to the first post maybe?
Quote from: zen-in on 05/26/2015 05:05 amYou should stick with Copper sheet. Cast Aluminum, even if it is pure Al will not have as good conductivity due to microcracks, slag inclusions, bubbles, etc. Aluminum is not forged because it cracks when heated and hit with hammers. A fine Silver cavity would have a higher Q than Copper, and would be much easier to form. Since there is not as much markup on Silver the cost would be about 5X the cost of Copper. A fusion weld can be done to close the cone with no discontinuity at the seam. For Copper you can get the cone crimped at the ends and use Be-Cu finger stock to bridge the flat ends (instead of solder) and adjustable slug with the cone. That would make it easy to disassemble. Later, when all is said and done it will make a good museum display. Thanks for the advice.I think you misunderstood, we would cast the aluminum in a dye and then use a computer controlled mill to shave of the excess. I'd imagine a 1 inch thick frustum that is well polished on the inside would have a better Q factor than a 20 mil copper sheet after several tests because it will be able to absorb much more heat without deforming. NWPU doesn't publish their dimensions, but the pictures seem to indicate a very thick cavity. The flight thruster also seems quite thick. I think we are probably going to end up trying both.Why don't you believe the EM Drive is producing a thrust?Seems to me most of the spurious effects have been eliminated, or at least minimized. The results are certainly inconsistent, but so are the experiments. Whatever the cause of this anomalous thrust, it has definitely stumped a lot of great minds for quite a while...Kurt
Thought experiment: Can people please supply thoughts/feedback on the followingIf a suitable length of fiber optic cable was acquired and wound around a hollow cylinder that was just bigger than the diameter of a cavity, such that the fiber cylinder fitted over top of the cavity. The fiber is hooked up to a laser light source. Either a second laser light source (or a half silvered mirror is used to split the original beam into two paths) such that both paths end their journey at a single visual screen. Could we achieve interferometry with a setup like this and therefore a means to test for the potential presence of G waves emitting from an active cavity?.Realising that both the second beam and the visual display unit would need to be some distance away from the cavity such that any effect on the primary beam is potentially noticeable (eg emerging G waves will be at atmospheric C) ORCould a coiled length of fiber optic attached to one end of the cavity achieve the same sort of result?There is a type of fiber made of some sort of plastic? material that is used in server rooms for short haul data.... might be useful?
I believe more experiments, much of them performed competently and honestly, have happened without results being publicly reported. We know that Dr. Yang has retreated from publicity because of potential military applications of her work. It can be assumed that Roger Shawyer has a specific interest in keeping certain information confidential, so that he can make good economic benefit from his work. It is also known the Boeing has an EMdrive interest, and as they do, then it is likely that Lockheed-Martin has some project at their "skunkworks" as well. With Chinese and American defense organizations involved, I imagine that Russia, and perhaps India, and European interests, also have programs related to the EMdrive and similar developments. Because of the significant military uses of the EMDrive, in addition to the commercial advantages, who can blame these organizations for being tight-lipped? It is also conceivable that these organizations, being in great competition with each other, may attempt to sabotage each other's work by the means of false data releases. Such subterfuge has happened in the past, in other areas of science and engineering, and I see no reason why it EMdrive research should be exempt from such actions.In light of this, the lack of reported results from tests done in vacuum should not make one presume that such tests haven't been done. I've considered the idea that USAF's latest X-37B mission may have some EMdrive experiment on board.But please realize that most of this is semi-informed speculation, and I don't claim to know specifics. I merely think it's likely that much is occurring sub-rosa.
...Do you remember the video of the EmDrive test published by some russian guy on YouTube?It was published in this thread as well - unfortunately I was unable to find the particular post.Anyway, meanwhile this video got deleted from the YouTube. And also from all other social networks which repost usually such videos. Might support the above theory.
Quote from: supryin on 05/26/2015 11:29 am...I remember a video from Russia in a vertical set-up. The video I remember involved a waveguide having one end closed and the other end open. ...I don't recall something unusual in the video, as it is known that open microwave waveguides will have propulsion as photons leave the waveguide: it is essentially a photon rocket with photons at microwave frequencies. It satisfies conservation of momentum. It is an inefficient method of space propulsion.
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The Russian author also had written words to the effect that he didn't have much resources to conduct a better test.
If this is the same video you are referring to, I suggest that the video may have been deleted from YouTube as the author may have been made aware that an open waveguide is supposed to behave this way, and therefore it was not noteworthy and not directly related to Shawyer's EM Drive invention which is a completely closed cavity.
...1kW photon thrust makes for only about 3µN, unless it is efficiently recycled (like photonic laser thruster by BAE) which I doubt is the case, the setup looked open enough to leak microwaves copiously around. If this is the video in question, I recall the scale registering a gram force or so, from those values I doubt this was due to just EM beamed force...
Maybe I missed some information due to my delay on following these threads. What are the characteristics of the cavities used by NASA? I mean the physical dimensions, the input power (I know this is around tenth of W) and the relative dielectric constant of the material used as a dielectric (HDPE). Could the latter be similar to conjugate polymers or some ceramic material with this value ranging to some 10^5?