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#2280 by meberbs on 02 Nov, 2016 13:19
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Put me in the category of skeptic because that's my nature.
But I'm also desperately wanting EmDrive to be what Shawyer claims it is...because of course think of the fantastic ramifications! Although, I find it hard to believe that I can walk under a hovering space plane with a second generation emdrive producing tons of thrust and not feel any force pushing down on me.
It seems like most everybody agrees that Shawyer's explanation of why EmDrive works is wrong. Here is a link to his paper http://www.emdrive.com/theorypaper9-4.pdf. I've read it, and at first glance it appears logical and consistent. I cannot find any mathematical mistakes or contractions. (I have an EE degree, but it's been years since I've practiced.)
Has anybody written a paper that very simply explains where in Shawyer's theory paper he makes a mistake? Where is he wrong in his math. Or where is he wrong in his assumptions on what his equations represent in reality?
There is a whole list of issues, I am not sure how you could have missed them, unless you just skimmed through. (Some of the mistakes are so basic, that it took me a while to first notice them, because I never thought to check if he got the direction of the force consistent)
First, he takes an equation derived for a constant area cylindrical waveguide and applies it to a closed resonator with tapered sides. This is at best approximately correct.
Second, he ignores the force on the side walls, which balances whatever the difference is between the force on the end plates.
Third, at equation 8, he incorrectly applies the frame transformation equation for velocity to a random difference of velocities when he is not transforming reference frames.
Fourth, he states (correctly) that the force on the large end is larger than the force on the small end (forces directed outwards from the center of the drive. While he does not make it clear in that paper, the claim (and results of most experiments) is acceleration small end first, contrary to the direction his theory predicts if you ignore all of the other mistakes he made.
These are some of the basic issues, there are also statements in the paper where the words sound good, until you try to parse meaning from them. For example:QuoteThus the reactions at the end plates are not constrained within a closed system of waveguide and beam but are reactions between waveguide and beam, each operating within its own reference frame, in an open system.
This statement has about as much meaning as "colorless green dreams sleep furiously."
I'd appreciate if you could confirm if you understand these issues, since recent conversations on this thread have made me doubt my ability to explain simple physics concepts. -
#2281 by RotoSequence on 02 Nov, 2016 13:34
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I'd be thrilled it if the thread would take a break from debating Shawyer for a while. It's rarely been productive when its come up; it takes a lot of time to discuss and many a post is spent going back and forth in repetitive exchange, which distracts from the goal of figuring out if EM drives do anything, and how much of anything they might do.
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#2282 by Chris Bergin on 02 Nov, 2016 13:37
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This EM Drive topic has been incredibly well behaved (from what I can tell, lack of mod reports, etc.) over recent months, but I'll just remind members that there's clearly opposing camps on this subject. So remember, keep it civil (which I believe you all are) and avoid the trap of having to repeat yourself too many times, especially with the attachments *cough* TheTraveller,
Make your case and follow up questions, but understand some people are convinced this works and some people are convinced it doesn't...but as with all threads on here, 99.9 percent of the "views" are from people not actually posting (guests, people reading, etc.) So you're mainly aiming to convince them, not people posting the opposing view.
As you were
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#2283 by dustinthewind on 02 Nov, 2016 13:48
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Put me in the category of skeptic because that's my nature.
But I'm also desperately wanting EmDrive to be what Shawyer claims it is...because of course think of the fantastic ramifications! Although, I find it hard to believe that I can walk under a hovering space plane with a second generation emdrive producing tons of thrust and not feel any force pushing down on me.
It seems like most everybody agrees that Shawyer's explanation of why EmDrive works is wrong. Here is a link to his paper http://www.emdrive.com/theorypaper9-4.pdf. I've read it, and at first glance it appears logical and consistent. I cannot find any mathematical mistakes or contractions. (I have an EE degree, but it's been years since I've practiced.)
Has anybody written a paper that very simply explains where in Shawyer's theory paper he makes a mistake? Where is he wrong in his math. Or where is he wrong in his assumptions on what his equations represent in reality?
There is a whole list of issues, I am not sure how you could have missed them, unless you just skimmed through. (Some of the mistakes are so basic, that it took me a while to first notice them, because I never thought to check if he got the direction of the force consistent)
First, he takes an equation derived for a constant area cylindrical waveguide and applies it to a closed resonator with tapered sides. This is at best approximately correct.
Second, he ignores the force on the side walls, which balances whatever the difference is between the force on the end plates.Quote from: DustinthewindIf the effective mass of the light doesn't change then I would agree it should all balance out (no net force). However, if there is some "effective" change in mass of the light inside at one end of the cavity as opposed to the other then I suspect there may not be a balance.
Third, at equation 8, he incorrectly applies the frame transformation equation for velocity to a random difference of velocities when he is not transforming reference frames.
Fourth, he states (correctly) that the force on the large end is larger than the force on the small end (forces directed outwards from the center of the drive. While he does not make it clear in that paper, the claim (and results of most experiments) is acceleration small end first, contrary to the direction his theory predicts if you ignore all of the other mistakes he made.
These are some of the basic issues, there are also statements in the paper where the words sound good, until you try to parse meaning from them. For example:QuoteThus the reactions at the end plates are not constrained within a closed system of waveguide and beam but are reactions between waveguide and beam, each operating within its own reference frame, in an open system.
This statement has about as much meaning as "colorless green dreams sleep furiously."Quote from: DustinthewindI think what he may be trying to say here is that there is a force on the frustum, and an apparent force on the light. As the light loses momentum/energy the cavity appears to be gaining momentum. If I am correct in my speculation, he may be observing that while exciting the cavity at a shorter wavelength than needed for resonance, when freely accelerating, that there is an effect of attenuation on the light and a bandwidth of photons appears inside such that the light is rapidly losing energy by a change in wavelength.
I'd appreciate if you could confirm if you understand these issues, since recent conversations on this thread have made me doubt my ability to explain simple physics concepts.
I understand what bothers you. I am trying to approach it from what I feel I may understand. Hopefully I can help clarify a mutual understanding of what is being observed (supposed experimental observations), so we can all better tackle what might be going on by asking this question here: https://forum.nasaspaceflight.com/index.php?topic=40959.msg1605614#msg1605614 -
#2284 by meberbs on 02 Nov, 2016 13:52
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1) The EmDrive works.
1. You state this as absolute fact. You are the only one here who does not accept the possibility that emDrive is an experimental error.
2) It generates 2 very different force characteristics that can and have been measured.
If you can't accept that reality, there is not a lot of common ground for discussion.
Here maybe you need to start and accept the guide waves are formed inside the frustum, with a shorter wavelength than external and the guide wavelength varies as the diameter varies. If you can't even accept the microwave engineering reality, you claimed there is not phase not guide wavelength inside a frustum, then we can't even get to the 1st step in understanding the operational characteristics of a EmDrive and how those characteristics must guide us to a theory that can explain their existence.
So the 1st step in understand EmDrive engineering is understand how the guide wavelength is altered by diameter and how that diameter enforced change allows some integer number of 1/2 waves to fit, end to end, between the physical distance between the end plates.
Do you agree this is what happens? I mean it is shown on all the simulation modeling by COMSOL, FEKO and Meeps. It is where we need to start to find agreement.
2. Your description of these forces has been lacking in clarity, (see dustinthewind's post above)
I have already posted before that according to classical theories (which is what Shawyer claims to use) The force on the large end is larger than that on the small end, though this is exactly balanced by the force on the sidewalls.
I have asked you many times for a physcial definition of guide wavelength, and at best you just repost an equation, without defining the meaning of the variables. The standard definition (distance between surface of constant phase), as you have agreed before, does not apply to a resonator. The pictures in your post imply "distance between nodes in the standing wave," but this doesn't makes sense for all mode shapes, and gives a couple discrete values, rather than a continuously varying value as your equation gives. The only way I can think of to define this would be to somehow break the standing wave into travelling wave components that would each then allow the phrase "surface of constant phase" to have meaning. This is hard to do though.
To answer your question at the end, it depends on what you mean by "this." If you mean that a standing wave pattern is setup that generates different forces on each end, then yes, as this was also shown by Egan.
Rather than the complicated RF stuff, I think the first thing we need to agree on is the definition of force. You still haven't answered my 2 questions about a simple system that mimics the forces on the small and large end of the emDrive (ignoring as Shawyer does the sidewalls).
P.S. I find it rather rude that you continue ignoring my questions, and in case you forgot rudeness is not allowed on this forum. -
#2285 by TheTraveller on 02 Nov, 2016 13:54
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Second, he ignores the force on the side walls, which balances whatever the difference is between the force on the end plates.
If the forces balanced there would not be any Thrust force to measure, yet the Thrust force is there and measurable by using nothing more than a scale or torsion pendulum.
Repeatedly saying all the forces balance out is just ignoring all the experimental evidence that they do not balance out. -
#2286 by meberbs on 02 Nov, 2016 13:59
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I am speaking in terms of classical theory which Shawyer claims his theory is consistent with. If you read my other posts you would see that I acknowledge the possibility of mechanisms outside classical physics that would provide an actual unbalanced force.Second, he ignores the force on the side walls, which balances whatever the difference is between the force on the end plates.
If the forces balanced there would not be any Thrust force to measure, yet the Thrust force is there and measurable by using nothing more than a scale or torsion pendulum.
Repeatedly saying all the forces balance out is just ignoring all the experimental evidence that they do not balance out.
Now, I would appreciate it if you responded to the questions I asked. -
#2287 by TheTraveller on 02 Nov, 2016 14:04
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P.S. I find it rather rude that you continue ignoring my questions, and in case you forgot rudeness is not allowed on this forum.
I have repeatedly explained the direction and the characteristics of the 2 forces that a EmDrive generates and can be measured. The forces are real and many have measured them.
1) EmDrive generates a Thrust force, with a vector small to big, that doesn't cause device acceleration but can be measured on a scale or torsion pendulum. Equation F = (2 Qu Df Pwr) / c
2) EmDrive generates a equal but opposite Reaction force, vector big to small, that can't be measured on a scale or torsion pendulum but can be measured via A = F/M on a test rig that allows free acceleration to occur.
Yes these forces and their characterists are not what most here have ever experienced, yet they are real.
Claiming all the forces must balance out is just not correct as the experimental data has shown since 2002.
I do truly hope that when you read the EW vac peer review paper in Dec 2016, you will start to accept these very strange force and their strange characterists are real and then spend time trying to work out why they are happening, instead of repeatedly claiming all the forces balance out and denying the experimental evidence. -
#2288 by kaublezw on 02 Nov, 2016 14:04
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I'd be thrilled it if the thread would take a break from debating Shawyer for a while. It's rarely been productive when its come up; it takes a lot of time to discuss and many a post is spent going back and forth in repetitive exchange, which distracts from the goal of figuring out if EM drives do anything, and how much of anything they might do.
Sorry for beating a dead horse with my questions. I am new to this thread. You guys have given me enough to chew on. Carry on. -
#2289 by dustinthewind on 02 Nov, 2016 14:10
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P.S. I find it rather rude that you continue ignoring my questions, and in case you forgot rudeness is not allowed on this forum.
I have repeatedly explained the direction and the characteristics of the 2 forces that a EmDrive generates and can be measured. The forces are real and many have measured them.
1) EmDrive generates a Thrust force, with a vector small to big, that doesn't cause device acceleration but can be measured on a scale or torsion pendulum. Equation F = (2 Qu Df Pwr) / c
2) EmDrive generates a equal but opposite Reaction force, vector big to small, that can't be measured on a scale or torsion pendulum but can be measured via A = F/M on a test rig that allows free acceleration to occur.Quote from: DustinthewindYes this above #2. Please be specific about #2. This force can't be #1 so it can't be the frustum accelerating in the same direction as the force from #1. It should be in the opposite direction. Why do you think this force is in the opposite direction as #1 and what is the force acting on. Please clarify this by describing what your are observing that makes you come to this conclusion. https://forum.nasaspaceflight.com/index.php?topic=40959.msg1605614#msg1605614
Yes these forces and their characterists are not what most here have ever experienced, yet they are real.
Claiming all the forces must balance out is just not correct as the experimental data has shown since 2002.
I do truly hope that when you read the EW vac peer review paper in Dec 2016, you will start to accept these very strange force and their strange characterists are real and then spend time trying to work out why they are happening, instead of repeatedly claiming all the forces balance out and denying the experimental evidence. -
#2290 by TheTraveller on 02 Nov, 2016 14:13
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I am speaking in terms of classical theory which Shawyer claims his theory is consistent with. If you read my other posts you would see that I acknowledge the possibility of mechanisms outside classical physics that would provide an actual unbalanced force.
There are no unbalanced forces involved.
All that is happening is a new effect, well new to some, that causes momentum transfer from the declining momentum in the EmWave as it grows longer inside the cavity due to declining cavity diameter to the frustum.
Big end plate axial radiation pressure toward the big end
-
( Side Wall axial radiation pressure toward the small end
+
Small end plate axial radiation pressure toward the small end
+
Accelerative Reaction force toward the small end )
=
0.
What unbalanced Force? -
#2291 by dustinthewind on 02 Nov, 2016 14:20
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Ok thank you for clarifying. It appears he is saying is that there is a Force on the cavity in one direction and a force on the light in the cavity in the other direction such that the light appears to be losing energy and that energy is being transferred to the cavity.I am speaking in terms of classical theory which Shawyer claims his theory is consistent with. If you read my other posts you would see that I acknowledge the possibility of mechanisms outside classical physics that would provide an actual unbalanced force.
There are no unbalanced forces involved.
All that is happening is a new effect, well new to some, that causes momentum transfer from the declining momentum in the EmWave as it grows longer inside the cavity due to declining cavity diameter to the frustum.
Big end plate axial radiation pressure toward the big end
-
( Side Wall axial radiation pressure toward the small end
+
Small end plate axial radiation pressure toward the small end
+
Accelerative Reaction force toward the small end )
=
0.
What unbalanced Force?
There appears to be a loss of wavelength of the photons in the cavity as they recycle back and forth that they are losing wavelength.
Let me ask you Traveler, have you directly observed such a change in the wavelength of the light in the cavity (a broadening of the bandwidth) during free acceleration with something like a spectrum analyzer or a similar instrument?
There appears to be another issue with Travelers description of the behavior of the cavity producing a force toward the big end plate but accelerating from Big to small end plate. I can't yet understand this issue. -
#2292 by TheTraveller on 02 Nov, 2016 14:20
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P.S. I find it rather rude that you continue ignoring my questions, and in case you forgot rudeness is not allowed on this forum.
I have repeatedly explained the direction and the characteristics of the 2 forces that a EmDrive generates and can be measured. The forces are real and many have measured them.
1) EmDrive generates a Thrust force, with a vector small to big, that doesn't cause device acceleration but can be measured on a scale or torsion pendulum. Equation F = (2 Qu Df Pwr) / c
2) EmDrive generates a equal but opposite Reaction force, vector big to small, that can't be measured on a scale or torsion pendulum but can be measured via A = F/M on a test rig that allows free acceleration to occur.Quote from: DustinthewindYes this above #2. Please be specific about #2. This force can't be #1 so it can't be the frustum accelerating in the same direction as the force from #1. It should be in the opposite direction. Why do you think this force is in the opposite direction as #1 and what is the force acting on. Please clarify this by describing what your are observing that makes you come to this conclusion. https://forum.nasaspaceflight.com/index.php?topic=40959.msg1605614#msg1605614
Yes these forces and their characterists are not what most here have ever experienced, yet they are real.
Claiming all the forces must balance out is just not correct as the experimental data has shown since 2002.
I do truly hope that when you read the EW vac peer review paper in Dec 2016, you will start to accept these very strange force and their strange characterists are real and then spend time trying to work out why they are happening, instead of repeatedly claiming all the forces balance out and denying the experimental evidence.
Experimental data shows that Thrust force #1 can be measured on a virtually non moving scale or torsion pendulum, yet it can NOT support acceleration in the direction of the Thrust force vector (small to big).
Likewise experimental data shows the equal but opposite Reaction force will not produce any indication on a scale but will accelerate the EmDrive and associated mass.
The difference is when the EmDrive is setting on a scale it can't move so there are no internal Doppler shifts occurring.
When it is free to move as on a rotary test rig, and it starts moving, and there are internal Doppler shifts.
So yes the forces that an EmDrive generates are VERY strange, yet they are real and have been measured. -
#2293 by Bob012345 on 02 Nov, 2016 14:22
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Again same comment: Why is it important that the waves in the frustum resonate?
A resonant cavities stored energy = input power * Q. Without resonance the cavity can't receive Rf energy. Resonance enables both Rf energy to enter the cavity and high Q allows the stored energy to be much greater than the input power.
Think of a cavity as a funny kind of capacitor that can only store energy at the resonant freq of the capacitor. Q is then like Farad and then the higher the Q, like the higher the Farad, the higher the stored energy inside.
It should be noted that resonance for a cavity needs some number of 1/2 guide waves to fit, end to end, inside the cavity between the physical end plates. If you measure the length of the cavity and calculate the length of a 1/2 wave external to the cavity, the 1/2 waves would not fit between the end plates. This is because inside the cavity the wavelength is longer than outside. These internal waves are called guide wave and their length varies as to the excited mode and cavity diameter. These images show the effect, where you can easily see that the guide wavelength is longer at the small end than at the large end. This altering guide wavelength vs diameter is the key to the EmDrive.
A wheel is also a kind of resonance. I never got a good answer to whether or not circulating waves in a wave guide with the proper asymmetry might be just as good as "resonance" in a cavity and a whole lot easier.
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#2294 by meberbs on 02 Nov, 2016 14:24
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My question was about a system where you bounce high momentum balls off one side, and low momentum balls off the other side (tossing from in between the 2 sides). The first question was "which direction would it move in." So an answer would be of the form "Towards the large end that you are tossing the high momentum balls at" You have made no such response. The second question was about describing the forces in that situation, but you have not talked about forces on balls in your posts. The point is to agree on what force means in a similar situation to the emDrive.P.S. I find it rather rude that you continue ignoring my questions, and in case you forgot rudeness is not allowed on this forum.
I have repeatedly explained the direction and the characteristics of the 2 forces that a EmDrive generates and can be measured. The forces are real and many have measured them.
1) EmDrive generates a Thrust force, with a vector small to big, that doesn't cause device acceleration but can be measured on a scale or torsion pendulum. Equation F = (2 Qu Df Pwr) / c
2) EmDrive generates a equal but opposite Reaction force, vector big to small, that can't be measured on a scale or torsion pendulum but can be measured via A = F/M on a test rig that allows free acceleration to occur.
Yes these forces and their characterists are not what most here have ever experienced, yet they are real.
Claiming all the forces must balance out is just not correct as the experimental data has shown since 2002.
I do truly hope that when you read the EW vac peer review paper in Dec 2016, you will start to accept these very strange force and their strange characterists are real and then spend time trying to work out why they are happening, instead of repeatedly claiming all the forces balance out and denying the experimental evidence.
I think the original post was more referring to my ongoing discussions with TheTraveller, which just go in circles, where he usually responds to my questions by repeating his original statements, which prompt me to point out the same issues. The main reason I respond is so people like you don't come by and only see the one side, since he hasn't understood my points up until now.I'd be thrilled it if the thread would take a break from debating Shawyer for a while. It's rarely been productive when its come up; it takes a lot of time to discuss and many a post is spent going back and forth in repetitive exchange, which distracts from the goal of figuring out if EM drives do anything, and how much of anything they might do.
Sorry for beating a dead horse with my questions. I am new to this thread. You guys have given me enough to chew on. Carry on.
I'd gladly agree to stop talking about it if he stops posting self contradictory points about Shawyer's theory, and stick to experimental design discussions (flat/curved end plates, circulators etc.) -
#2295 by TheTraveller on 02 Nov, 2016 14:26
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Let me ask you Traveler, have you directly observed such a change in the wavelength of the light in the cavity during free acceleration with something like a spectrum analyzer or a similar instrument?
I have yet to conduct acceleration studies. the changes would be VERY small and I suggest very difficult to detect. Sort of like the 1st Laser Ring Gyros trying to detect the phase shift induced from differential path lengths due to rotation.
The change in the internal dual travelling waves is what would be expected from existing physics. It is like saying have you accelerated away from a star and seen the light Red shift, then accelerated toward the start and seen the light Blue shift. I suggest we both accept the Doppler shifting would occur, without ever seeing it happen. -
#2296 by meberbs on 02 Nov, 2016 14:28
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One more time, as I posted before: you just clearly said that F1 + F2 + F3 + ma = 0I am speaking in terms of classical theory which Shawyer claims his theory is consistent with. If you read my other posts you would see that I acknowledge the possibility of mechanisms outside classical physics that would provide an actual unbalanced force.
There are no unbalanced forces involved.
All that is happening is a new effect, well new to some, that causes momentum transfer from the declining momentum in the EmWave as it grows longer inside the cavity due to declining cavity diameter to the frustum.
Big end plate axial radiation pressure toward the big end
-
( Side Wall axial radiation pressure toward the small end
+
Small end plate axial radiation pressure toward the small end
+
Accelerative Reaction force toward the small end )
=
0.
What unbalanced Force?
According to Newtonian mechanics, F1 + F2 + F3 = ma. There is a fundamental difference in these equations that is an unresolvable contradiction. m*a is not a force, it is the result of an unbalanced force. -
#2297 by TheTraveller on 02 Nov, 2016 14:31
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I think the original post was more referring to my ongoing discussions with TheTraveller, which just go in circles, where he usually responds to my questions by repeating his original statements, which prompt me to point out the same issues. The main reason I respond is so people like you don't come by and only see the one side, since he hasn't understood my points up until now.
I did comment on the ball example saying that the example you presented did not represent what happens inside the cavity.
Eventually you will be forced to accept the 2 VERY strange forces I have described, that the EmDrive generates, are very real and any theory of operation needs to describe why they are generated and act in the VERY strange way they do. -
#2298 by TheTraveller on 02 Nov, 2016 14:34
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One more time, as I posted before: you just clearly said that F1 + F2 + F3 + ma = 0I am speaking in terms of classical theory which Shawyer claims his theory is consistent with. If you read my other posts you would see that I acknowledge the possibility of mechanisms outside classical physics that would provide an actual unbalanced force.
There are no unbalanced forces involved.
All that is happening is a new effect, well new to some, that causes momentum transfer from the declining momentum in the EmWave as it grows longer inside the cavity due to declining cavity diameter to the frustum.
Big end plate axial radiation pressure toward the big end
-
( Side Wall axial radiation pressure toward the small end
+
Small end plate axial radiation pressure toward the small end
+
Accelerative Reaction force toward the small end )
=
0.
What unbalanced Force?
According to Newtonian mechanics, F1 + F2 + F3 = ma. There is a fundamental difference in these equations that is an unresolvable contradiction. m*a is not a force, it is the result of an unbalanced force.
Yet the forces exist and have the characterists as claimed. Write what you will, the reality of the forces will not change.
BTW the last time I checked a Force can be a change in momentum, which is what happens inside the EmDrive. -
#2299 by meberbs on 02 Nov, 2016 14:43
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And I explained that it produces the same net effect, reflecting things of different momentum off 2 opposing surfaces. If we can't agree on the description of forces in this simple system, how can we agree on the description for the emDrive?I think the original post was more referring to my ongoing discussions with TheTraveller, which just go in circles, where he usually responds to my questions by repeating his original statements, which prompt me to point out the same issues. The main reason I respond is so people like you don't come by and only see the one side, since he hasn't understood my points up until now.
I did comment on the ball example saying that the example you presented did not represent what happens inside the cavity.
Eventually you will be forced to accept the 2 VERY strange forces I have described, that the EmDrive generates, are very real and any theory of operation needs to describe why they are generated and act in the VERY strange way they do.
You clearly still don't understand basic mechanics, which is why I want you to answer those 2 questions about a simple mechanical system. The only evidence for the contradictory forces I have seen is statements from you and Shawyer, and both you and Shawyer have demonstrated a lack of understanding of how to calculate forces.One more time, as I posted before: you just clearly said that F1 + F2 + F3 + ma = 0
According to Newtonian mechanics, F1 + F2 + F3 = ma. There is a fundamental difference in these equations that is an unresolvable contradiction. m*a is not a force, it is the result of an unbalanced force.
Yet the forces exist and have the characterists as claimed. Write what you will, the reality of the forces will not change.
BTW the last time I checked a Force can be a change in momentum, which is what happens inside the EmDrive.
But I'm also desperately wanting EmDrive to be what Shawyer claims it is...because of course think of the fantastic ramifications! Although, I find it hard to believe that I can walk under a hovering space plane with a second generation emdrive producing tons of thrust and not feel any force pushing down on me.
