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#3200 by LasJayhawk on 13 May, 2015 02:48
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...
Best Regards,
Todd
Barely able to keep pace Todd...its a good thing. maximizing asymmetry in attenuation different from absorption like the stuff I used to work with?
http://www.westernrubber.com/products/himag-microwave-absorbers/himag-cavity-resonance-absorbers/
It is getting pretty hot and heavy in here and I'm not sure I am keeping up either. Love it though.
I've been mulling around the ideas of harmonics and wondered if anyone has considered injecting 2 RF sources into the cavity,
One set and the other variable in frequency? I've been slowly working my way through this but like I said it's been slow. I welcome and inputs and thoughts.
I've been wondering about that, and also it looks like this has a high reflected, so feeding it with a 4 port circulator and running the reflected back into antenna 2, and it's reflected into antenna 3. -
#3201 by deltaMass on 13 May, 2015 03:06
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A comment from http://www.masinaelectrica.com/emdrive-independent-test/Quote
I was hoping to build a mini EmDrive using modified intruder alarm (22 GHz) modules as these can be tuned by simply adjusting the voltage and physical dimensions of the Gunn diodes resonant cavity.
On reflection, not so hot. Only about 200 mW from these things.
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#3202 by WarpTech on 13 May, 2015 03:18
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...
@WarpTech or other proponents of "dependence of the effect on acceleration", please run the numbers. What would be the acceleration of frustum needed to really drift out of bandwidth for Q around 10000 or otherwise reach a magnitude significant to behaviour of waves inside ?
I read it in Shawyer's recent paper, he simulated it on a computer. I don't have that type of software. I've been wishing I did for decades. Since the system moves by attenuation and dissipation, the photons lose momentum and are red-shifted, while the frustum either gains momentum or gains heat from them.
You're correct, that the momentum it gains from the photons is in the direction of the photons, but results from the difference in the attenuation in each direction. The photons lose more momentum moving inward than moving outward, because they become evanescent waves. They do not increase their energy, except what they can take away from the frustum.
So I see it like ringing a bell. It is the exponential decay from a higher energy state that is giving the thrust. Attempting to make the Q very high to sustain resonance requires reducing the losses, but it is the losses that give it thrust. So... Shawyer increases the angle to make it more like a pill box. Anything over pi/6 is very close to a pill box. Then it should have a higher Q, but it should also have less efficient use of it.
If a photon rocket is: F/P = 1/c
and the Frustum is: F/P ~ Q/c x pulse width
Design efficiency should then target: (F*c)/(P*Q) = 1 but in practice < 1
This would imply maximizing thrust with a lower value of Q, i.e., we do not want to maximize Q, we want to maximize asymmetry in the attenuation, which is what I'm working on at the moment.
Best Regards,
Todd
Barely able to keep pace Todd...its a good thing. maximizing asymmetry in attenuation different from absorption like the stuff I used to work with?
http://www.westernrubber.com/products/himag-microwave-absorbers/himag-cavity-resonance-absorbers/
Well, that would appear to "fit" my conjecture and equations nicely. I would assume, if the frustum walls where partially lined with this stuff except for the big end plate, which needs to be highly reflective. Then even more losses would be in the forward direction. The design would need to strike a balance between reflection and absorption. Perhaps only line the frustum walls near the big end, but leave most of the walls reflective to allow a relatively high Q?
IMO, this might do the trick simply because if more momentum is absorbed here, it's less absorbed somewhere else, and it can take the heat. One thing I didn't see on their data sheet is; what is the difference in absorption as a function of angle?
I'll caveat this by adding, it could also very well just add to the heat generation and not add to the momentum transfer. I think it is worth looking into further.
Todd D.
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#3203 by Notsosureofit on 13 May, 2015 03:24
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Entropy is keeping me out of bed....I'm too old for this (etc. etc.)
Force is dependent on the rate of change of entropy, (need to get to a thermo book tomorrow), so depends on Power. Degree of change depends on ratio of order to disorder, so Q as representing the difference between a highly monochromatic frequency distribution and the Boltzman distribution of the dissipated power as heat IN AN ASYMMETRICAL FORM DEPENDENT ON THE CAVITY SHAPE AND THE MODE !
Good Night ! (I hope ??)
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#3204 by WarpTech on 13 May, 2015 05:42
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Entropy is keeping me out of bed....I'm too old for this (etc. etc.)
Force is dependent on the rate of change of entropy, (need to get to a thermo book tomorrow), so depends on Power. Degree of change depends on ratio of order to disorder, so Q as representing the difference between a highly monochromatic frequency distribution and the Boltzman distribution of the dissipated power as heat IN AN ASYMMETRICAL FORM DEPENDENT ON THE CAVITY SHAPE AND THE MODE !
Good Night ! (I hope ??)
Oh I get it! EM Drive = Entropy Maximization Drive !
Good night!
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#3205 by SeeShells on 13 May, 2015 06:04
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I'm not looking at that dirty, more a controlled dirty in the harmonics and sub-harmonics. I remember looking at the spectrum of a magnetron years ago and was appalled at the wild mixture spewing out of it. I don't think a magnetron will do unless a notch filters are used. Still working my way through it, but time for bed....
Best Regards,
Todd
Barely able to keep pace Todd...its a good thing. maximizing asymmetry in attenuation different from absorption like the stuff I used to work with?
http://www.westernrubber.com/products/himag-microwave-absorbers/himag-cavity-resonance-absorbers/
It is getting pretty hot and heavy in here and I'm not sure I am keeping up either. Love it though.
I've been mulling around the ideas of harmonics and wondered if anyone has considered injecting 2 RF sources into the cavity,
One set and the other variable in frequency? I've been slowly working my way through this but like I said it's been slow. I welcome and inputs and thoughts.
From what I gather a magnetron source is full of harmonics and subharmonics...one called it "dirty" which is a good visual... spectrum-wise. -
#3206 by TheTraveller on 13 May, 2015 08:28
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Email received from Roger Shawyer in regard to a question to verify if Dr. Rodal's Df excel equation is correct.
Shawyer also cautions, very strongly, on the dangers of working with high power microwave systems.
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#3207 by deltaMass on 13 May, 2015 09:50
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The mapping Shawyer defines can be modelled by
DF = 1 - c-d
where d = difference in diameters >=0
and c is some constant >=1; c=e for example -
#3208 by frobnicat on 13 May, 2015 10:10
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...
Best Regards,
Todd
Barely able to keep pace Todd...its a good thing. maximizing asymmetry in attenuation different from absorption like the stuff I used to work with?
http://www.westernrubber.com/products/himag-microwave-absorbers/himag-cavity-resonance-absorbers/
It is getting pretty hot and heavy in here and I'm not sure I am keeping up either. Love it though.
I've been mulling around the ideas of harmonics and wondered if anyone has considered injecting 2 RF sources into the cavity,
One set and the other variable in frequency? I've been slowly working my way through this but like I said it's been slow. I welcome and inputs and thoughts.
Maybe first try to state what kind of nonlinear coupling effects could be at play to make a difference ? Linear system => result(wave1+wave2)=result(wave1)+result(wave2) so doing wave1+wave2 would bring nothing new, qualitatively, without a mechanism to explain result(single wave)!=0 in the first place...
Side note : no harm but you are skipping some quote closing, that mixes up citations.
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#3209 by deltaMass on 13 May, 2015 11:31
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I don't know if anyone's tried to minimise the all-up mass budget, but with batteries I can't see it going much below 50 Kg. There should be no rotating components like fans in the equipment. There will be heat but try to arrange to exhaust it orthogonal to the expected motion. Perhaps use a Teflon-on-Teflon channel for motion. It must be carefully levelled. Air must be still (smoke sticks!). Stiction may be an issue. Then let's compare EW to Juan, assuming 50 Kg all-up mass, assuming (at least initially) constant acceleration:
F=100 uN: a = 2*10-6 m/s2; t(1 cm) = 100 secs; t(10 cm) = 316 secs
F = 0.7 N: a = 0.014 m/s2; t(1 cm) = 1.2 secs; t(10 cm) = 3.8 secs
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#3210 by Notsosureofit on 13 May, 2015 12:55
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Entropy is keeping me out of bed....I'm too old for this (etc. etc.)
Force is dependent on the rate of change of entropy, (need to get to a thermo book tomorrow), so depends on Power. Degree of change depends on ratio of order to disorder, so Q as representing the difference between a highly monochromatic frequency distribution and the Boltzman distribution of the dissipated power as heat IN AN ASYMMETRICAL FORM DEPENDENT ON THE CAVITY SHAPE AND THE MODE !
Good Night ! (I hope ??)
Oh I get it! EM Drive = Entropy Maximization Drive !
Good night!
Well, yes, in that sense. The entropy is one more condition, like the Equivalence Principle, that the EM drive has to satisfy. The interesting point is that the entropy change can be related to a force vector. Think back to the semi-permeable membrane example in Thermodynamics 1. -
#3211 by Rodal on 13 May, 2015 12:57
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Email received from Roger Shawyer in regard to a question to verify if Dr. Rodal's Df excel equation is correct.
...
http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=829894
The equation that you refer to was derived by me as an honest effort to elucidate variables, "reading tea leaves", that Shawyer had not explicitly defined (originally with @aero and others to compare numerical predictions with experimental measurements).
You repeatedly asked me for Shaywer's Design Factor equation. Obviously, if you had been given the Design Factor equation by Shawyer, or if this expression was obvious to you from reading Shawyer's writings, there was no point in asking me for Shaywer's Design Factor (I hope and fully expect that in that case you would have made Shawyer's Design Factor available to the forum).
What was expected from Shawyer, the author of the equation, is to produce his equation: to answer "this is my equation:..." (defining the Design Factor and its variables, and not resorting to references where the variables are not explicitly defined). Instead, his response, relayed through you as a messenger, communicating behind a curtain, is an unconstructive response: Shawyer's Design Factor equation is never provided. Certainly not provided to this forum (was his equation provided instead to you in private?). Not a response one would expect in an Engineering or a Scientific journal, where the editors expect disclosure (and hence a definition) of what is being discussed (in this case what is Shawyer's Design Factor equation ?) before asserting that somebody's interpretation is wrong.
This response stands in direct contrast to the direct, constructve responses of others: Paul March (NASA) who consistently provided geometrical dimensions, defined variables, and provided honest answers to honest questions. Same for Prof. McCulloch who answered questions directly (not using messengers) both in this forum and in his blog, instead of keeping obscure what are his equations.
I look forward to your providing to this forum what is Shawyer's Design Factor equation (and then we can have a discussion of my effort to ascertain Shawyer's Design Factor, vis-ŕ-vis Shawyer's previous papers that I had to rely on).
I also look forward to Shawyer providing the big and small diameters and the length of the truncated cones used in his experiments, so that this forum can verify the claims being made in his papers regarding the validity of his Design Factor (instead of having to rely on assessing dimensions from photographs, or resorting to parametrization of variables over a whole range, as NASA had to do to guess Shawyer's dimensions). -
#3212 by RegMaster on 13 May, 2015 13:18
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Hi, I'm new in this forum. I'm from Spain, and my english is not perfect.
I have been reading this "infinite" thread several days, but here are too many technical concepts that are in some cases dificult to understand when I read it (due lenguage translation limitations).
I was thinking very much about this EM Drive technology, their physics principies and other many advanced physics concepts.
IMHO, EM Drive would be related to this:
http://en.wikipedia.org/wiki/Ronald_Mallett#Time_travel_research
Where microwaves are too photons like láser, but in other frequencies... I think that truncated cone works as a type of "well", but in a very inneficient form. I think that the reflectivity is not the main problem, but the angle of microwaves injected in the chamber and their relation between diameter and microwave frequency....
You can see that this path, with microwaves reflected in a shape of "well" can generate a "spiral" resonance o s-wave inside the chamber, raising the efficient of EM Drive joint it with Mallett article.
Is this posible?
sorry for my english. -
#3213 by Rodal on 13 May, 2015 13:51
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The mapping Shawyer defines can be modelled by
Yes, what you state would be a possible (one of several) valid interpretation(s) of Shawyer's latest message relayed here: http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=829894.
DF = 1 - c-d
where d = difference in diameters >=0
and c is some constant >=1; c=e for example
However, that's not the mapping defined in Shawyer's previous published papers. -
#3214 by Rodal on 13 May, 2015 14:01
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Entropy is keeping me out of bed....I'm too old for this (etc. etc.)
Force is dependent on the rate of change of entropy, (need to get to a thermo book tomorrow), so depends on Power. Degree of change depends on ratio of order to disorder, so Q as representing the difference between a highly monochromatic frequency distribution and the Boltzman distribution of the dissipated power as heat IN AN ASYMMETRICAL FORM DEPENDENT ON THE CAVITY SHAPE AND THE MODE !
Good Night ! (I hope ??)
Oh I get it! EM Drive = Entropy Maximization Drive !
Good night!
Well, yes, in that sense. The entropy is one more condition, like the Equivalence Principle, that the EM drive has to satisfy. The interesting point is that the entropy change can be related to a force vector. Think back to the semi-permeable membrane example in Thermodynamics 1.
It is also interesting because the 2nd law of Thermodynamics is an emergent law: it is not intrinsically (*) present in Einstein's General Relativity, and not intrinsically present in Quantum Mechanics. Yet a lot of effort has been devoted here and elsewhere (**) in analyzing the EM Drive (including energy paradoxes) without taking into account entropy.
___________
(*) Of course there are multiple papers considering entropy as an add-on to Einstein's GR, e.g. entropy considerations in Black Holes, etc.
(**) A general statement, as Shawyer's, Prof. Yang's and Dr. White's considerations (or those of their critics, to the extent I can recall) have not explicitly considered the 2nd Law of thermodynamics in their published papers.Quote from: Sir Arthur Stanley Eddington,The law that entropy always increases holds, I think, the supreme position among the laws of Nature. If someone points out to you that your pet theory of the universe is in disagreement with Maxwell's equations — then so much the worse for Maxwell's equations. If it is found to be contradicted by observation — well, these experimentalists do bungle things sometimes. But if your theory is found to be against the second law of thermodynamics I can give you no hope; there is nothing for it but to collapse in deepest humiliation.
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#3215 by rrb6699 on 13 May, 2015 14:11
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I have a belief concept of the universe and dark energy. perhaps I don't know the term, but I believe since everything from the atom to the solar system to galaxies and beyond follow a specific atom-like pattern, AND because we cannot identify the smallest particle or the largest "particle", then everything taps into the same place. since there can be no smallest particle, otherwise it has to be comprised of something smaller, then it must be a passage to or through to negative or dark energy. I believe we are about to tap into this energy and it will be the key to everything including distant travel in short times, but, it may not be like we imagine in science fiction. it may be we can pass through at an atomic level. I believe space travel as a whole body may be possible this way, but, will be limited distance until we find the key to the universe at the atomic level. but possibly both will be discovered simultaneously if we can just recognize it. Just a thought of many roaming around my mind. -
#3216 by WarpTech on 13 May, 2015 14:37
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...
...
Todd and Notsosureofit:
I found a textbook that is in Google Books that has some formulas (including calculating the Q) for (slabs and also for coaxial) dielectric inserts in a cylindrical cavity. See this:
The Google URL is huge, I hope this URL shortener works:
start at page 111 on this link http://bit.ly/1FiKoz6
Propagation, Scattering and Dissipation of Electromagnetic Waves
By A. S. Ilʹinskiĭ, A. Ya Slepyan
Series: IEEE Electromagnetic Waves Series (Book 36)
Publisher: The Institution of Engineering and Technology; First Edition edition (December 2, 1993)
ISBN-10: 0863412831
ISBN-13: 978-0863412837
Hopefully this can help you further in analyzing the thrust of a cylindrical EM Drive with a dielectric insert
That is a really good book! I wish I owned it. The previous sections before pg. 111 cover modes in a cylinder, sphere and cone. Very good read!
I also found this one last night, regarding attenuation in a lossy waveguide. It's elementary, and I like that!
http://www.radioeng.cz/fulltexts/2011/11_02_472_478.pdf
Todd
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#3217 by Rodal on 13 May, 2015 14:43
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...
Best Regards,
Todd
Barely able to keep pace Todd...its a good thing. maximizing asymmetry in attenuation different from absorption like the stuff I used to work with?
http://www.westernrubber.com/products/himag-microwave-absorbers/himag-cavity-resonance-absorbers/
It is getting pretty hot and heavy in here and I'm not sure I am keeping up either. Love it though.
I've been mulling around the ideas of harmonics and wondered if anyone has considered injecting 2 RF sources into the cavity,
One set and the other variable in frequency? I've been slowly working my way through this but like I said it's been slow. I welcome and inputs and thoughts.
Maybe first try to state what kind of nonlinear coupling effects could be at play to make a difference ? Linear system => result(wave1+wave2)=result(wave1)+result(wave2) so doing wave1+wave2 would bring nothing new, qualitatively, without a mechanism to explain result(single wave)!=0 in the first place...
Kudos to SeeShells !!!!! (do we need more hot and heavy weather to keep producing these great suggestions )
This from this paper recently brought up by Todd (hat tip to WarpTech), which confirms the validity of SeeShells suggestion:
http://www.radioeng.cz/fulltexts/2011/11_02_472_478.pdf
Attenuation in Rectangular Waveguides with Finite Conductivity Walls
Kim Ho YEAP, Choy Yoong THAM, Ghassan YASSIN, Kee Choon YEONG
RADIOENGINEERING, VOL. 20, NO. 2, JUNE 2011Quote from: Kim Ho YEAP, Choy Yoong THAM, Ghassan YASSIN, Kee Choon YEONGAn important consequence of this
work is the demonstration that the loss computed for degenerate
modes propagating simultaneously is not simply
additive. In other words, the combined loss of two co-existing
modes is higher than adding the losses of two modes
propagating independently. This can be explained by the
mode coupling effects, which is significant when the phase
constants of two propagating modes are different yet very
close. -
#3218 by Notsosureofit on 13 May, 2015 14:53
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Quote
An important consequence of this
work is the demonstration that the loss computed for degenerate
modes propagating simultaneously is not simply
additive. In other words, the combined loss of two co-existing
modes is higher than adding the losses of two modes
propagating independently. This can be explained by the
mode coupling effects, which is significant when the phase
constants of two propagating modes are different yet very
close.
Yes, this is the condition for a resonant cavity in an accelerating frame, and a limit on EM type drives. -
#3219 by TheTraveller on 13 May, 2015 15:01
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Email received from Roger Shawyer in regard to a question to verify if Dr. Rodal's Df excel equation is correct.
...
http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=829894
The equation that you refer to was derived by me as an honest effort to elucidate variables, "reading tea leaves", that Shawyer had not explicitly defined (originally with @aero and others to compare numerical predictions with experimental measurements).
You repeatedly asked me for Shaywer's Design Factor equation. Obviously, if you had been given the Design Factor equation by Shawyer, or if this expression was obvious to you from reading Shawyer's writings, there was no point in asking me for Shaywer's Design Factor (I hope and fully expect that in that case you would have made Shawyer's Design Factor available to the forum).
What was expected from Shawyer, the author of the equation, is to produce his equation: to answer "this is my equation:..." (defining the Design Factor and its variables, and not resorting to references where the variables are not explicitly defined). Instead, his response, relayed through you as a messenger, communicating behind a curtain, is an unconstructive response: Shawyer's Design Factor equation is never provided. Certainly not provided to this forum (was his equation provided instead to you in private?). Not a response one would expect in an Engineering or a Scientific journal, where the editors expect disclosure (and hence a definition) of what is being discussed (in this case what is Shawyer's Design Factor equation ?) before asserting that somebody's interpretation is wrong.
This response stands in direct contrast to the direct, constructve responses of others: Paul March (NASA) who consistently provided geometrical dimensions, defined variables, and provided honest answers to honest questions. Same for Prof. McCulloch who answered questions directly (not using messengers) both in this forum and in his blog, instead of keeping obscure what are his equations.
I look forward to your providing to this forum what is Shawyer's Design Factor equation (and then we can have a discussion of my effort to ascertain Shawyer's Design Factor, vis-ŕ-vis Shawyer's previous papers that I had to rely on).
I also look forward to Shawyer providing the big and small diameters and the length of the truncated cones used in his experiments, so that this forum can verify the claims being made in his papers regarding the validity of his Design Factor (instead of having to rely on assessing dimensions from photographs, or resorting to parametrization of variables over a whole range, as NASA had to do to guess Shawyer's dimensions).
Here is my latest email to Roger Shawyer, where I asked him to please provide me his Df equation in either Excel format or to modify your shared Df equation:QuoteHi Roger,
I have posted your email to the forum and agree working with high power anything can be dangerous. Your warning is very timely as others are buying magnetrons and screwing them to homemade cavities.
My approach is to use a programmable Rf generator (with programmable output level), connected to a max 20W Rf amp and SLOWLY increase the power applied as I vary the Rf frequency to parametrise the cavities characteristics. My cavity and Rf amplifier will be inside a tight Alum mesh 6 sided Faraday Cage (FC) to ensure no energy gets out to cause any problems. Even with the FC in place, I don't plan on getting any closer than 2 meters when it is powered on. Like you I have seen what high power and high voltage in high Q circuits can do.
As I really don't like working with bad data nor reinventing the wheel, would you please send me your Df equation in either excel or just as a corrected formula in the form below.
This would really help me understand the dynamics occurring inside a cavity as the applied Rf versus the Df derived from that frequency and cavity dimensions vary.
If I understand you correctly, no matter what the frequency nor cavity dimensions, the calculated Df should always be in the range 0 - 1 even if the small end diameter is below the cutoff frequency? In the Rodal version, if I set a really large big diameter, a really large length, small diameter to 0.299705m, the Df does = 1.0000 at 1GHz but will go above 1 if the small end diameter is less than the frequency wavelength (less than 0.299705m at 1GHz). Should that not happen?
Cl = cavity length
Cb = cavity big end diameter
Cs = cavity small end diameter
f = applied frequency
c = light speed in selected medium
Df = 2c * (Cl^2) * SQRT(4 + (c / (Cl * f))^2) * f * (Cb - Cs) /
(4 * Cb * Cs * (Cl * f)^2 + (c^2) * (Cb * Cs - (2 * Cl)^2))
My intention has been made clear, to openly share everything I learn and experience during my journey to replicate the Shawyer Teeter-Totter balance beam test rig and the Flight Thruster.
When given a new equation for the EM Drive, I will write an Excel spreadsheet to allow all variables to be varied, observe the results and try to learn about how this device works. Which is what I did with your equation, and discovered there appears to be a optional frequency that gives the highest Df for a fixed set of cavity dimensions.
Further to what I learned from Shawyer, I have verified your equation does conditionally match what Shawyer claims for his Df.
Big diameter matches small diameter, Df = 0. Frequency and length variation have no effect.
Very large big diameter AND very long length, Df = 1, when small diameter matches frequency wavelength. When small diameter is larger than wavelength Df < 1, when small diameter is less than wavelength Df > 1. I note Shawyer did not mention than cavity length would have an effect on Df at this boundary condition but it does.
I'm not here to score points nor take sides. I will follow the data to where it leads me, will safely replicate the Flight Thruster and openly share that journey. I do appreciate your assistance in providing your Df equation and further thoughts.
Peace.
