Quick note on Iulian's test; this was his third attempt. Unless I'm missing something, wouldn't have any thermal effects have shown up on those earlier tests at least in some form or was his measurements not accurate enough to measure that small of an effect?Not as quick note on the Internet. With all due respect to Dr. Rodal- his characterization of the Internet (http://forum.nasaspaceflight.com/index.php?topic=36313.msg1375139#msg1375139) is a bit inaccurate. Yes, there are plenty of distractions to be had, but to those with developed critical thinking skills, the Internet can be a fantastic tool.In fact, the Internet was invented *for discussions just like this one*. Scientists getting together to share information and collaborate in new ways across distance and experience. This discussion has been an amazing example of social science application of this tool. Besides Dr. Rodal and the EW team's contributions, there's been several DIYers, mathematicians, skeptics, and scientists of all strips all tossing in ideas. But then, out of that, there's been WarpTech's now known 'Todd Conjecture'. SeeShell's waveform expertise, seeing microwaves in hot tubs. Iulian's new much-debated video. Contributions from around the world. All the people working together here that have been pushing the literal boundaries of human understanding. Having watched the Internet grow from it's ARPA/DARPA days in the 70's and 80's through to the ubiquitous tool that it is today, seeing exploration like this happening is an amazing experience; no matter *what* comes of this EM drive experimentation. Yes, it's a bit like the Tower of Babel come to life, millions of voices all reaching out at once. But the Internet is a tool. And like any tool used in the hands of those with critical thinking skills, it becomes a powerful tool indeed.Keep up the good work! This is an amazing time in human history to be doing science.
The picture of the wire frame end plate of a frustum got me to thinking a little out of the box. If a frustum were constructed of screen wire, like a window screen - wire, not that plastic stuff, wouldn't it resonate, too? At very low power it could keep its shape but at higher power mightn't it measurably deform from the internal optical pressure? And since we know the strength of the screen wire and the optical pressure from plane waves, couldn't we determine whether or not there was excess force being generated? Perhaps a more simple construction would be from a solid copper conic section and copper screens on the ends attached in such a way as to encourage the deformation.My point being that so far, all of the experiments have been constructed to serve as a rocket engine, but no one has made an experiment to look at the forces directly. Might there not be a more suitable configuration to look at the cavity forces than the frustum? And if we knew for sure that strange forces existed wouldn't that help the effort?
Quote from: aero on 05/19/2015 02:51 amThe picture of the wire frame end plate of a frustum got me to thinking a little out of the box. If a frustum were constructed of screen wire, like a window screen - wire, not that plastic stuff, wouldn't it resonate, too? At very low power it could keep its shape but at higher power mightn't it measurably deform from the internal optical pressure? And since we know the strength of the screen wire and the optical pressure from plane waves, couldn't we determine whether or not there was excess force being generated? Perhaps a more simple construction would be from a solid copper conic section and copper screens on the ends attached in such a way as to encourage the deformation.My point being that so far, all of the experiments have been constructed to serve as a rocket engine, but no one has made an experiment to look at the forces directly. Might there not be a more suitable configuration to look at the cavity forces than the frustum? And if we knew for sure that strange forces existed wouldn't that help the effort?That's a great way to conduct research on optimization and to understand something complicated. It reminds me of how the first human powered plane design came about. The Gossamer Condor beat the MIT design (that was based on analysis) by evolutionary refinement of the design based on a large number of tests.
Quote from: TheTraveller on 05/19/2015 01:54 amI wonder what, if anything would result if there were a perfectly cylindrical 1/4 wave stub on one side of the source emitter and a frustum at 3/4 wavelength long on the other side of the emitter. The 1/4 wave stub side on the big end would resonate, and the frustum would attenuate. Engineered asymmetry with a much simpler resonant cavity.Todd D.Is this the psychic blog? Great idea! I had a similar thought and have been mulling it over on how to apply it still using the EM snow cone shape. I asked if anyone had thought of using 2 insertion sites into the cavity and the answer I got, it might be considered this next go around of tests. I'm not sure a perfect cylinder would get the effects we're looking for. I think first is finding out what we are seeing that's causing this CoE and CoM abnormality, but it sure would be quite inexpensive to design, build and test so you could just to plug in and see. It would also give you some very solid baseline data from very well known formulas.
I wonder what, if anything would result if there were a perfectly cylindrical 1/4 wave stub on one side of the source emitter and a frustum at 3/4 wavelength long on the other side of the emitter. The 1/4 wave stub side on the big end would resonate, and the frustum would attenuate. Engineered asymmetry with a much simpler resonant cavity.Todd D.
Quote from: WarpTech on 05/19/2015 02:33 amQuote from: TheTraveller on 05/19/2015 01:54 amI wonder what, if anything would result if there were a perfectly cylindrical 1/4 wave stub on one side of the source emitter and a frustum at 3/4 wavelength long on the other side of the emitter. The 1/4 wave stub side on the big end would resonate, and the frustum would attenuate. Engineered asymmetry with a much simpler resonant cavity.Todd D.Is this the psychic blog? Great idea! I had a similar thought and have been mulling it over on how to apply it still using the EM snow cone shape. I asked if anyone had thought of using 2 insertion sites into the cavity and the answer I got, it might be considered this next go around of tests. I'm not sure a perfect cylinder would get the effects we're looking for. I think first is finding out what we are seeing that's causing this CoE and CoM abnormality, but it sure would be quite inexpensive to design, build and test so you could just to plug in and see. It would also give you some very solid baseline data from very well known formulas.I get the impression the current in the 1/4 wave stub moves with the electric field of the incoming radiation for constructive interference and the 3/4 frustum I am guessing would be working against the radiation and be attenuated. Is this similar to a directional antenna array? I am not quite seeing the picture but I think I might understand the concept.
Quote from: TheTraveller on 05/19/2015 01:54 amI have read the 3 papers many times. Where did she state that? In what table? The 2010 paper I linked and the attached table makes it VERY clear the highest thrust came with the highest Q.BTW I doubt you can get a good frustum Q measurement using a broadband microwave source as the frequency is all over the place and not at 2.45GHz. So the observed bandwidth would be as wide as a barn door because the wide band magnetron output is as wide as a barn door.I see now this was your assumption and not from the paper.Again I state that if you read the 2010 paper, it is VERY clear the higher the Q, the higher the thrust. Nothing the Chinese nor Shawyer has presented goes against that.As to how to get a frustum that has constantly varying internal wavelengths to resonate at each end plate, from a different applied Rf wavelength, well I'm working on that. Might be my secret squirrel secret sauce.The only way the frustum can gain momentum from the EM waves inside is if those waves are attenuated on each cycle, asymmetrically.
I have read the 3 papers many times. Where did she state that? In what table? The 2010 paper I linked and the attached table makes it VERY clear the highest thrust came with the highest Q.BTW I doubt you can get a good frustum Q measurement using a broadband microwave source as the frequency is all over the place and not at 2.45GHz. So the observed bandwidth would be as wide as a barn door because the wide band magnetron output is as wide as a barn door.I see now this was your assumption and not from the paper.Again I state that if you read the 2010 paper, it is VERY clear the higher the Q, the higher the thrust. Nothing the Chinese nor Shawyer has presented goes against that.As to how to get a frustum that has constantly varying internal wavelengths to resonate at each end plate, from a different applied Rf wavelength, well I'm working on that. Might be my secret squirrel secret sauce.
Frustum movement (increased Kinetic energy of the frustum from stored cavity energy) causes the cavity to detune, increasing Q energy losses,dropping Q, dropping impedance, causing more microwave energy to enter the cavity, causing increased energy draw from the primary electrical source. Conserving CofE.
..I was the one that said that optimizing for a higher Q is counterproductive for generating thrust, not Yang. Here is my logic;The only way the frustum can gain momentum from the EM waves inside is if those waves are attenuated on each cycle, asymmetrically. The Q is the energy stored/loss per cycle. So increasing Q by decreasing the loss per cycle, effectively it MUST reduce the amount of attenuation such that there is less thrust transferred to the frustum. Alternatively, if you increase Q by storing more energy, without altering the amount of power attenuated, then there is more energy in reserve to draw from. If the system used PWM, it could sustain a longer duty cycle.So there are advantages to higher Q that can produce a higher thrust, but optimizing Q at the expense of reducing the attenuation, will lower the thrust, IMO....
...I wonder what, if anything would result if there were a perfectly cylindrical 1/4 wave stub on one side of the source emitter and a frustum at 3/4 wavelength long on the other side of the emitter. The 1/4 wave stub side on the big end would resonate, and the frustum would attenuate. Engineered asymmetry with a much simpler resonant cavity.Todd D.
Probably wouldn't need to use screen, just ultra thin copper bases. They should deform in one direction or the other. The direction of the deformation would say a lot about the force. ...
Quote from: Einstein79 on 05/17/2015 02:10 pmQuote from: TheTraveller on 05/15/2015 07:36 amDoes the Flight Thruster have a slightly concave top and convex bottom? Would appear so from the gaps.Enhanced the photo as much as I can for those wishing to try to extract dimensions as this photo is better that the original as it has no distortion.If we can find the dimension<M The big end most certainly should be convex and the small end concave, relative from the outside of course. The big end and small end radii should not be coincidence but offset having the small end radius much larger than the big end. In fact, it might be better for the small end to be flat. If either end is flat, the bounce will introduce very significant phase distortion into the returning curved wave. For me it is hard to see that Shawyer ever used flat end plates INSIDE the cavity. As we never saw inside the cavity, what is to say he didn't use curved end plates inside and flat end covers outside? What he drew may not be what he built.
Quote from: TheTraveller on 05/15/2015 07:36 amDoes the Flight Thruster have a slightly concave top and convex bottom? Would appear so from the gaps.Enhanced the photo as much as I can for those wishing to try to extract dimensions as this photo is better that the original as it has no distortion.If we can find the dimension<M The big end most certainly should be convex and the small end concave, relative from the outside of course. The big end and small end radii should not be coincidence but offset having the small end radius much larger than the big end. In fact, it might be better for the small end to be flat.
Does the Flight Thruster have a slightly concave top and convex bottom? Would appear so from the gaps.Enhanced the photo as much as I can for those wishing to try to extract dimensions as this photo is better that the original as it has no distortion.If we can find the dimension<M
QuoteFrustum movement (increased Kinetic energy of the frustum from stored cavity energy) causes the cavity to detune, increasing Q energy losses,dropping Q, dropping impedance, causing more microwave energy to enter the cavity, causing increased energy draw from the primary electrical source. Conserving CofE.I'm afraid electrical circuits don't work quite like that, although it must be said that it's indeed a valiant attempt at rationality. Typically, you see, anything that causes a source and a load to transition away from a matched state will result in less power being transferred from source to load, not more.
Ultimately what Shawyer's and White's theories amount to, is that there is a radiation pressure imbalance on the inside of the cavity, resulting in a net force, which is a non small fraction of the total radiation pressure on the inside of the cavity (more than 1%). Shawyer says it is in accordance with Maxwell's equations, which is flat out wrong.
Quote from: deltaMass on 05/19/2015 09:29 amQuoteFrustum movement (increased Kinetic energy of the frustum from stored cavity energy) causes the cavity to detune, increasing Q energy losses,dropping Q, dropping impedance, causing more microwave energy to enter the cavity, causing increased energy draw from the primary electrical source. Conserving CofE.I'm afraid electrical circuits don't work quite like that, although it must be said that it's indeed a valiant attempt at rationality. Typically, you see, anything that causes a source and a load to transition away from a matched state will result in less power being transferred from source to load, not more.So an easy way to test if the EMdrive works, would be to build a low power unit (1 watt or less). Then with the system powered and tuned move it! Any movement along the thrust axis should have a corresponding effect on the cavity resonance. This may be far easier to detect and confirm than the very small forces developed so far.Mike