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#2360 by Rodal on 14 May, 2016 16:14
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See here rfmyguy's spectrum analysis of one of his magnetrons. It starts very close to 2.45Ghz and then drifts to 2.445Ghz as the magnetron heats. I do not think the frequencies emitted by a magnetron are close enough to 2.4575Ghz to excite TM212, even when the dirty magnetron signal is accounted for.
Which shows that Shawyer could be more helpful to DIY builders by posting the exact internal dimensions of his DEMONSTRATOR EM Drive, instead of rehashing his "explanations" for EM Drive which according to him require only Newton, Maxwell and Special Relativity: nothing new beyond "Basic Science". -
#2361 by Monomorphic on 14 May, 2016 16:36
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Which shows that Shawyer could be more helpful to DIY builders by posting the exact internal dimensions of his DEMONSTRATOR EM Drive
Most definitely. It is no easy task to design an emdrive that resonates at a particular mode over the range of frequencies that a standard magnetron emits over a period of 1 minute.
This is in fact what I am working on right now. Different modes react differently. For example, the TE012 mode pattern stays intact over a longer frequency range than the TE013.
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#2362 by TheTraveller on 14 May, 2016 17:17
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See here rfmyguy's spectrum analysis of one of his magnetrons. It starts very close to 2.45Ghz and then drifts to 2.445Ghz as the magnetron heats. I do not think the frequencies emitted by a magnetron are close enough to 2.4575Ghz to excite TM212, even when the dirty magnetron signal is accounted for.
Which shows that Shawyer could be more helpful to DIY builders by posting the exact internal dimensions of his DEMONSTRATOR EM Drive, instead of rehashing his "explanations" for EM Drive which according to him require only Newton, Maxwell and Special Relativity: nothing new beyond "Basic Science".
Roger has assisted my DIY build efforts quite a lot. For both my 1st flat end plate build that recorded 8mN of thrust and for my 2nd professional machined build that should achieve a higher specific & peak thrust than his Flight Thruster as it can be driven by 250 to 2,500Wrf.
I have encountered nothing that causes me to doubt the validity of Roger's theory work, as using it generates data that matches real world results. I also know more than I can share on the multiple theory validation processes.
As my health is improving, I'll soon be able to restart work on finishing my 1st frustum build (currently it is gravity stacked as the end flanges are missing) & then plan to mount it on an Emmett Brown like rotary test rig:
http://forum.nasaspaceflight.com/index.php?topic=39772.msg1511554#msg1511554
Will then post the experimental data, photos & video.
The S band spherical end plate thruster is still in design & may change to Al with Ni, Ag & Au coatings as EW used for their Al frustum.
Commercially available EmDrives will happen in 2016. BTW I have no interest in sharing the industrial trade secrets I have developed. Of course other will try to reverse engineer what I have developed and they are welcome to try but it will cost them $50k per thruster. -
#2363 by TheTraveller on 14 May, 2016 17:21
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Which shows that Shawyer could be more helpful to DIY builders by posting the exact internal dimensions of his DEMONSTRATOR EM Drive
Most definitely. It is no easy task to design an emdrive that resonates at a particular mode over the range of frequencies that a standard magnetron emits over a period of 1 minute.
This is in fact what I am working on right now. Different modes react differently. For example, the TE012 mode pattern stays intact over a longer frequency range than the TE013.
Don't believe everything FEKO tells you. Like other analysis packages it gets cutoff wrong. I know as I found out the hard way. Have verified this with Roger. -
#2364 by meberbs on 14 May, 2016 17:27
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Thanks to Phil in Australia who found Paul Stansell's public science report he used with his ISEF science experiment. It is attached below.
Thanks Rfmw,
this is how an experimental report should be written. It is still scant on method and could benefit from more photos but it raises the bar for the rest of us. Clear and unreserved descriptions of what, how and why. Well done Mr Stansell, please keep up the good work. JMN..
PDF added because I couldn't make the link work
Overall this is well written, but there is some room for improvement as well. First one of the good points:QuoteThe proposition of such a technology comes with harsh skepticism from the scientific community because such a technology seems to violate two of the most fundamental principles of physics – conservation of momentum and conservation of energy.
It is standard to start a scientific paper with a review of background information, most of which is already known to people familiar with the field, but is useful for people new to the area of research. When investigating anomalies such as the EMDrive, it also lets people know that you understand that standard theories don't allow it to work, and that you do know how to do a force balance (if you don't know how to do a force balance, how can you measure a force correctly?).
...
However it has not yet been confirmed without doubt that this is a feasible form of propulsion and that detected thrusts are not due to experimental error. Thus there is no accepted mechanism of thrust production but rather a number of complex competing theories
One of the biggest issues in my opinion is that the conclusions are not supported by the evidence in the paper. While the conclusions all state that the hypothesis was confirmed, the real conclusion is stated in the future work section:QuoteThe biggest problem that was faced during the research campaign was the issue of thermal air currents causing buoyant forces three orders of magnitude greater than the EMDrive force. This meant that regardless of the frustum’s orientation the EMDrive force could not be detected above the air buoyancy force.
Sometimes in science the conclusion is that no conclusion can be made (see Tajmar for another example of this) This is still a useful result, as it supports the conclusions many in these threads have drawn that a knife edge balance is not an ideal setup for the measurement emDrives. This is an easy mistake to make, because experimenters naturally want to be able to state a clear conclusion.
The hypotheses were effectively 2 hypotheses each: that resonance would (or would not) be achieved and that the frustum would move (or not move). The non resonating ones were listed as confirmed despite the frustum moving. Also differences in the resonating and non-resonating motion were cited as proof of resonance, when no direct measurements of resonance were taken (unless I missed something).
Based on Monomorphic's analysis, it is not obvious that there was good resonance in either case, and that the observed differences weren't due to another uncontrolled for effect.FEKO run of Paul Stansell's frustum. In my humble opinion, his issue is the same as some DIYers I have seen. They used NASA's frustum dimensions with a ~2.45Ghz magnetron. Which may sound good, but NASA's frustum does not resonate at 2.445Ghz - 2.45Ghz - the operating frequency range of most household microwaves. I have not run a sim of his 5cm tuning add-on yet. Hope to do that soon.
Also, there is a fundamental problem with this statement:QuoteDue to the swinging of the knife-edge fulcrum negative values do occur and can be ignored to produce the following graph.
If the oscillations affected the measurement results, you have to account for it on both up and down directions. You don't get to truncate it to zero, and the best way to handle this is probably average the measurements (depending on the setup, other more advanced calibration could be used). Cutting off the numbers introduces an arbitrary bias. If the oscillations have that significant of an effect, they should have been added to the discussion of error sources. -
#2365 by meberbs on 14 May, 2016 17:34
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Which shows that Shawyer could be more helpful to DIY builders by posting the exact internal dimensions of his DEMONSTRATOR EM Drive
Most definitely. It is no easy task to design an emdrive that resonates at a particular mode over the range of frequencies that a standard magnetron emits over a period of 1 minute.
This is in fact what I am working on right now. Different modes react differently. For example, the TE012 mode pattern stays intact over a longer frequency range than the TE013.
Don't believe everything FEKO tells you. Like other analysis packages it gets cutoff wrong. I know as I found out the hard way. Have verified this with Roger.
There has been exactly zero experimental evidence to support your statement. All evidence has been that all of the analysis programs used in these threads have correctly predicted resonance when used correctly (unit mistakes and such have caused issues, but that is user error). I do not believe there has been a single case where the prediction was not accurate to within parameters such as the accuracy of the build geometry.
If you have an example shape where Maxwell's equations predict resonance, but an experiment shows no resonance due to some "cutoff," please share this geometry since this would be an incredible and revolutionary discovery of new physics.
Edit: I am glad to hear that you are feeling better. -
#2366 by Rodal on 14 May, 2016 17:37
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So, you post your $50k price promotion here:Which shows that Shawyer could be more helpful to DIY builders by posting the exact internal dimensions of his DEMONSTRATOR EM Drive
Most definitely. It is no easy task to design an emdrive that resonates at a particular mode over the range of frequencies that a standard magnetron emits over a period of 1 minute.
This is in fact what I am working on right now. Different modes react differently. For example, the TE012 mode pattern stays intact over a longer frequency range than the TE013.
Don't believe everything FEKO tells you. Like other analysis packages it gets cutoff wrong. I know as I found out the hard way. Have verified this with Roger....BTW I have no interest in sharing the industrial trade secrets I have developed. Of course other will try to reverse engineer what I have developed and they are welcome to try but it will cost them $50k per thruster.
while claiming that FEKO, a commercial package for which a number of well-known companies worldwide pay license fees for, gets a simple cut-off condition wrong, a cut-off condition which can be solved with a simple formula from introductory textbooks.
Can you please show your (or Shawyer's) FEKO's computer modeling for an open waveguide, comparing FEKO with the exact solution for cut-off and showing how FEKO gets it wrong?
______________
PS: The EM Drive is not an open waveguide (it has metallic end walls) and therefore that cut-off condition is the wrong equation to apply for a closed cavity like the EM Drive. -
#2367 by Monomorphic on 14 May, 2016 17:45
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Of course other will try to reverse engineer what I have developed and they are welcome to try but it will cost them $50k per thruster.
What do we get for $50,000? Just the frustum? Or will you include the RF source, test rig, and other RF test equipment? -
#2368 by rfmwguy on 14 May, 2016 17:47
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Non-commercial guys...just sayin'
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#2369 by rfmwguy on 14 May, 2016 17:56
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See here rfmyguy's spectrum analysis of one of his magnetrons. It starts very close to 2.45Ghz and then drifts to 2.445Ghz as the magnetron heats. I do not think the frequencies emitted by a magnetron are close enough to 2.4575Ghz to excite TM212, even when the dirty magnetron signal is accounted for.
This is the exact problem that plagues all of us. You have to be spot on with resonance. Like Doc said, its a shame we didn't have exact dimensions from original builders but suppose that's to be expected from a commercial entity. The original EW dimensions certainly were off 2450 even if an insert was introduced, which lowers resonance frequency.
I built a "dummy" frustum out of aluminum sheets and PC board to get my final dimensions and hopefully the old magnetron and the new frustum connect somewhere...my hope anyway. -
#2370 by X_RaY on 14 May, 2016 18:05
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Fine for you. I have real world experience in development for this type of cavities with one side below the cutoff diameter (usable for propagation calculations in circular waveguides!) using both approximating formulas as well as FEA. These calculations are well proven and verified experimentally (VNA). For calculation below this diameter the sin/cos term in the equations simply changes to its hyperbolic versions. And of course the resonant frequency with one end below cutoff is solveable(Like Dr.Rodal showed in his paper). FEA also gives correct value even in more complex situations such as with dielectric inserts. Believe what you want, field analyzes works well.Which shows that Shawyer could be more helpful to DIY builders by posting the exact internal dimensions of his DEMONSTRATOR EM Drive
Most definitely. It is no easy task to design an emdrive that resonates at a particular mode over the range of frequencies that a standard magnetron emits over a period of 1 minute.
This is in fact what I am working on right now. Different modes react differently. For example, the TE012 mode pattern stays intact over a longer frequency range than the TE013.
Don't believe everything FEKO tells you. Like other analysis packages it gets cutoff wrong. I know as I found out the hard way. Have verified this with Roger. -
#2371 by TheTraveller on 14 May, 2016 18:07
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Which shows that Shawyer could be more helpful to DIY builders by posting the exact internal dimensions of his DEMONSTRATOR EM Drive
Most definitely. It is no easy task to design an emdrive that resonates at a particular mode over the range of frequencies that a standard magnetron emits over a period of 1 minute.
This is in fact what I am working on right now. Different modes react differently. For example, the TE012 mode pattern stays intact over a longer frequency range than the TE013.
Don't believe everything FEKO tells you. Like other analysis packages it gets cutoff wrong. I know as I found out the hard way. Have verified this with Roger.
There has been exactly zero experimental evidence to support your statement. All evidence has been that all of the analysis programs used in these threads have correctly predicted resonance when used correctly (unit mistakes and such have caused issues, but that is user error). I do not believe there has been a single case where the prediction was not accurate to within parameters such as the accuracy of the build geometry.
If you have an example shape where Maxwell's equations predict resonance, but an experiment shows no resonance due to some "cutoff," please share this geometry since this would be an incredible and revolutionary discovery of new physics.
Edit: I am glad to hear that you are feeling better.
Thanks for the health mention. Yes it is good to be able to see a light at the end of a long tunnel.
BTW my 8mN is real. So something is happening that is outside currently accepted theory.
Roger advised me packages like FEKO & others do not properly model what happens in reality at the small end, near cutoff. Advised me to never go below diam in mtrs X 0.82 in TE013 expressed as drive freq despite what any analysis package indicated was not at cutoff.
As existing physics says the EmDrive should not work but it does work, just maybe the assumptions used in the modelers to determine small end cutoff in a tapered waveguide with reflecting end plates just might not be as accurate as you may assume. -
#2372 by TheTraveller on 14 May, 2016 18:18
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Fine for you. I have real world experience in development for this type of cavities with one side below the cutoff diameter (usable for propagation calculations in circular waveguides!) using both approximating formulas as well as FEA. These calculations are well proven and verified experimentally (VNA). For calculation below this diameter the sin/cos term in the equations simply changes to its hyperbolic versions. And of course the resonant frequency with one end below cutoff is solveable(Like Dr.Rodal showed in his paper). FEA also gives correct value even in more complex situations such as with dielectric inserts. Believe what you want, field analyzes works well.Which shows that Shawyer could be more helpful to DIY builders by posting the exact internal dimensions of his DEMONSTRATOR EM Drive
Most definitely. It is no easy task to design an emdrive that resonates at a particular mode over the range of frequencies that a standard magnetron emits over a period of 1 minute.
This is in fact what I am working on right now. Different modes react differently. For example, the TE012 mode pattern stays intact over a longer frequency range than the TE013.
Don't believe everything FEKO tells you. Like other analysis packages it gets cutoff wrong. I know as I found out the hard way. Have verified this with Roger.
Try building an EmDrive with too small a small end and see what happens. I know as I tried to push the small end dia down as the DF & thrust goes up very quickly. But I was below Roger's 0.82 rule & I learned a lesson that while packages like FEKO and others do a good job drawing nice graphics, for dealing with cutoff realities in an EmDrive, they don't generate a usable real world result.
So either respect Roger's 0.82 small end cutoff rule or not. Not my concern as my build works just fine. -
#2373 by Rodal on 14 May, 2016 18:22
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This prescription could be a valid prescription to ensure that the energy density is located as close as possible to the small end of the EM Drive. Instead of interpreting the prescription as "FEKO and other similar software packages cannot be believed", it may instead mean that FEKO and other packages are correct, but what matters is not only that the cavity is in resonance, but also how close is the energy density peak to the small end of the EM Drive.Which shows that Shawyer could be more helpful to DIY builders by posting the exact internal dimensions of his DEMONSTRATOR EM Drive
Most definitely. It is no easy task to design an emdrive that resonates at a particular mode over the range of frequencies that a standard magnetron emits over a period of 1 minute.
This is in fact what I am working on right now. Different modes react differently. For example, the TE012 mode pattern stays intact over a longer frequency range than the TE013.
Don't believe everything FEKO tells you. Like other analysis packages it gets cutoff wrong. I know as I found out the hard way. Have verified this with Roger.
There has been exactly zero experimental evidence to support your statement. All evidence has been that all of the analysis programs used in these threads have correctly predicted resonance when used correctly (unit mistakes and such have caused issues, but that is user error). I do not believe there has been a single case where the prediction was not accurate to within parameters such as the accuracy of the build geometry.
If you have an example shape where Maxwell's equations predict resonance, but an experiment shows no resonance due to some "cutoff," please share this geometry since this would be an incredible and revolutionary discovery of new physics.
Edit: I am glad to hear that you are feeling better.
Thanks for the health mention. Yes it is good to be able to see a light at the end of a long tunnel.
BTW my 8mN is real. So something is happening that is outside currently accepted theory.
Roger advised me packages like FEKO & others do not properly model what happens in reality at the small end, near cutoff. Advised me to never go below diam in mtrs X 0.82 in TE013 expressed as drive freq despite what any analysis package indicated was not at cutoff.
As existing physics says the EmDrive should not work but it does work, just maybe the assumptions used in the modelers to determine small end cutoff in a tapered waveguide with reflecting end plates just might not be as accurate as you may assume.
This prescription may be a simple rule of hand as to how to ensure that the energy density peak is located close to the small end, once one picks a given mode shape, like TE013.
Most of these packages do not have standard facility to plot the energy density, but as Monomorphic has shown one can visualize the energy density peak from the E and B fields. If one has the small diameter below the cutoff for an open waveguide, there maybe a region close to the small end without a significant intensity of the fields, which is not as good as having the energy density peak as close as possible to the small end. -
#2374 by TheTraveller on 14 May, 2016 18:25
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See here rfmyguy's spectrum analysis of one of his magnetrons. It starts very close to 2.45Ghz and then drifts to 2.445Ghz as the magnetron heats. I do not think the frequencies emitted by a magnetron are close enough to 2.4575Ghz to excite TM212, even when the dirty magnetron signal is accounted for.
This is the exact problem that plagues all of us. You have to be spot on with resonance. Like Doc said, its a shame we didn't have exact dimensions from original builders but suppose that's to be expected from a commercial entity. The original EW dimensions certainly were off 2450 even if an insert was introduced, which lowers resonance frequency.
I built a "dummy" frustum out of aluminum sheets and PC board to get my final dimensions and hopefully the old magnetron and the new frustum connect somewhere...my hope anyway.
It is very important the end plates are very highly parallel, like to better than 100um or better still 25um. You may not see much improvement on VNA numbers but it only tells a small part of the story. Tuning for max thrust, under power, tells a very different story, which I learned from experience. -
#2375 by X_RaY on 14 May, 2016 18:27
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The only reason is you believe unrestricted in R.Shawyer? Thanks for the conversation
Fine for you. I have real world experience in development for this type of cavities with one side below the cutoff diameter (usable for propagation calculations in circular waveguides!) using both approximating formulas as well as FEA. These calculations are well proven and verified experimentally (VNA). For calculation below this diameter the sin/cos term in the equations simply changes to its hyperbolic versions. And of course the resonant frequency with one end below cutoff is solveable(Like Dr.Rodal showed in his paper). FEA also gives correct value even in more complex situations such as with dielectric inserts. Believe what you want, field analyzes works well.Which shows that Shawyer could be more helpful to DIY builders by posting the exact internal dimensions of his DEMONSTRATOR EM Drive
Most definitely. It is no easy task to design an emdrive that resonates at a particular mode over the range of frequencies that a standard magnetron emits over a period of 1 minute.
This is in fact what I am working on right now. Different modes react differently. For example, the TE012 mode pattern stays intact over a longer frequency range than the TE013.
Don't believe everything FEKO tells you. Like other analysis packages it gets cutoff wrong. I know as I found out the hard way. Have verified this with Roger.
Try building an EmDrive with too small a small end and see what happens. I know as I tried to push the small end dia down as the DF & thrust goes up very quickly. But I was below Roger's 0.82 rule & I learned a lesson that while packages like FEKO and others do a good job drawing nice graphics, for dealing with cutoff realities in an EmDrive, they don't generate a usable real world result.
So either respect Roger's 0.82 small end cutoff rule or not. Not my concern as my build works just fine.
BTW did you know about any prefered reference frame for the emdrive related to general relativity? -
#2376 by TheTraveller on 14 May, 2016 18:30
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...Most of these packages do not have standard facility to plot the energy density, but as Monomorphic has shown one can visualize the energy density peak from the E and B fields. If one has the small diameter below the cutoff for an open waveguide, there maybe a region close to the small end without a significant intensity of the fields, which is not as good as having the energy density peak as close as possible to the small end.
Violate Roger's 0.82 rule and there will be no thrust. Don't need any software package to tell you that as none can. -
#2377 by Rodal on 14 May, 2016 18:35
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To put this in context:See here rfmyguy's spectrum analysis of one of his magnetrons. It starts very close to 2.45Ghz and then drifts to 2.445Ghz as the magnetron heats. I do not think the frequencies emitted by a magnetron are close enough to 2.4575Ghz to excite TM212, even when the dirty magnetron signal is accounted for.
This is the exact problem that plagues all of us. You have to be spot on with resonance. Like Doc said, its a shame we didn't have exact dimensions from original builders but suppose that's to be expected from a commercial entity. The original EW dimensions certainly were off 2450 even if an insert was introduced, which lowers resonance frequency.
I built a "dummy" frustum out of aluminum sheets and PC board to get my final dimensions and hopefully the old magnetron and the new frustum connect somewhere...my hope anyway.
It is very important the end plates are very highly parallel, like to better than 100um or better still 25um. You may not see much improvement on VNA numbers but it only tells a small part of the story. Tuning for max thrust, under power, tells a very different story, which I learned from experience.
100 um = 0.004 inches
25 um = 0.001 inches (one thousands of an inch)
some builders are using only 1 mm copper, some are using thicker
1 mm = 1000 um
1 mm = 0.039 inch
so this specification for parallelism is asking to be parallel within 1/10 or 1/40 of that thickness of the copper walls ! !
Since it is easy to deform a plate to a fraction of its thickness, the only way to ensure this parallelism is to have much thicker walls than 1 mm -
#2378 by TheTraveller on 14 May, 2016 18:37
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The only reason is you believe unrestricted in R.Shawyer? Thanks for the conversation
I built a working EmDrive following only Roger's advise. While 8mN at 95W forward power is not a lot of thrust, it is 80x what EW achieved and a long way above SnowFlake thrust levels.
Based on that result, I'll be making EmDrives commercially available in 2016. -
#2379 by X_RaY on 14 May, 2016 18:43
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I wish you good luck. Let's hope the thrust force is with you.The only reason is you believe unrestricted in R.Shawyer? Thanks for the conversation
I built a working EmDrive following only Roger's advise. While 8mN at 95W forward power is not a lot of thrust, it is 80x what EW achieved and a long way above SnowFlake thrust levels.
Based on that result, I'll be making EmDrives commercially available in 2016.
