According to the model, size scales linearly with frequency, but thrust only scales with increased power. IMO, a smaller device will have a more difficult time keeping cool and staying asymmetrical. My thoughts are toward larger devices running at MHz, so they can get higher power input and have the surface area to dissipate the heat.
So you're thinking that the asymetrical heat dissipation equates to asymmetrical energy dissipation, and the larger the asymmetry in energy dissipation, the greater the gravitational thrust the frustum generates to offset that asymmetry?
So, in addition to cooling fins on the large end, should the small end be thermally insulated?
Let the mud fly! 
"Performance also improves with the lowest order mode frequency"
So your theory predicts improved thrust for TM010, TE111, TM011, and TE011 over the often discussed TE013? Would TM010 have the greatest thrust since it is the lowest order mode?
It doesn't look like you've taken spherical end-caps into account. There is a significant difference in the internal volume when using spherical end-caps. I want to work up a FEKO model that incorporates your "ratio of the radii, Rb/Rs = 1.500." and "The length L should be no longer than Rs is wide, shorter is better and the performance improves as 1/L." Should I use flat or spherical end-caps?
My model uses a cylinder with flat end-caps. Spherical end caps should increase the Q and will increase the thrust, provided the differential dissipation is the same and favors the big end.
Regarding mode "shapes", I'm still mulling that over but the model says the lower the frequency and shorter the length, the better the performance, like a tapered pill-box.
Engineering reality says modes that have eddy currents crossing from end plate to side wall is a hard yakka build. Especially if the end plate needs to be removed to tune the coupler position. As Dave discovered, even what he thought was a good external solder seam around each end plate, had internally gaps and where the gaps were and eddy currents needed to flow, resulted in arching across the gap.
Exciting in TE01x mode eliminates end plate to side wall eddy currents and makes removable end plates possible.
According to the model, size scales linearly with frequency, but thrust only scales with increased power. IMO, a smaller device will have a more difficult time keeping cool and staying asymmetrical. My thoughts are toward larger devices running at MHz, so they can get higher power input and have the surface area to dissipate the heat.
Thrust also scales with Q as Dave discovered.
Lower freq means larger frustum, which also gives high Q, higher specific force and more surface area to radiate heat. Of course in space, with good thermal design, the frustum may be passively cooled to ~7K without needing cryo fluids.
According to the model, size scales linearly with frequency, but thrust only scales with increased power. IMO, a smaller device will have a more difficult time keeping cool and staying asymmetrical. My thoughts are toward larger devices running at MHz, so they can get higher power input and have the surface area to dissipate the heat.
Thrust also scales with Q as Dave discovered.
Lower freq means larger frustum, which also gives high Q, higher specific force and more surface area to radiate heat. Of course in space, with good thermal design, the frustum may be passively cooled to ~7K without needing cryo fluids.
How do you explain the "Q Conundrum". If the Q was infinite, meaning no RF energy was dissipated inside the fustrum where would the energy come from to create thrust? In all cases when energy is removed from a cavity the Q is reduced. What is it about the EM-Drive that makes this not the case? Isn't it another example where CoE is violated? Has anyone collected data from a functioning EM-Drive that shows this relation between Q and thrust?
According to the model, size scales linearly with frequency, but thrust only scales with increased power. IMO, a smaller device will have a more difficult time keeping cool and staying asymmetrical. My thoughts are toward larger devices running at MHz, so they can get higher power input and have the surface area to dissipate the heat.
Thrust also scales with Q as Dave discovered.
Lower freq means larger frustum, which also gives high Q, higher specific force and more surface area to radiate heat. Of course in space, with good thermal design, the frustum may be passively cooled to ~7K without needing cryo fluids.
Once we get to engineered devices (effect is proven, not trying to do super-high resolution experiments to prove the effect and tease out the exact nature of the physics driving it), we will have many more options to get the required high heat dissipation. For example, two-phase evaporation heat transfer on the frustum would produce extremely high heat transfer coefficients. Then you can move the heat rejection to space to other places on the body of the craft. Little to no new technology required, just a straightforward adaptation to a new application.
mh
Let the mud fly!
"Performance also improves with the lowest order mode frequency"
So your theory predicts improved thrust for TM010, TE111, TM011, and TE011 over the often discussed TE013? Would TM010 have the greatest thrust since it is the lowest order mode?
It doesn't look like you've taken spherical end-caps into account. There is a significant difference in the internal volume when using spherical end-caps. I want to work up a FEKO model that incorporates your "ratio of the radii, Rb/Rs = 1.500." and "The length L should be no longer than Rs is wide, shorter is better and the performance improves as 1/L." Should I use flat or spherical end-caps?
My model uses a cylinder with flat end-caps. Spherical end caps should increase the Q and will increase the thrust, provided the differential dissipation is the same and favors the big end.
Regarding mode "shapes", I'm still mulling that over but the model says the lower the frequency and shorter the length, the better the performance, like a tapered pill-box.
Here an example with dimensions for a relative flat frustum and TE011 at 2.45GHz.
Todd, is this kind of design what you are talking about?
Rb/Rs=1.5
L <Rs
According to the model, size scales linearly with frequency, but thrust only scales with increased power. IMO, a smaller device will have a more difficult time keeping cool and staying asymmetrical. My thoughts are toward larger devices running at MHz, so they can get higher power input and have the surface area to dissipate the heat.
Thrust also scales with Q as Dave discovered.
Lower freq means larger frustum, which also gives high Q, higher specific force and more surface area to radiate heat. Of course in space, with good thermal design, the frustum may be passively cooled to ~7K without needing cryo fluids.
How do you explain the "Q Conundrum". If the Q was infinite, meaning no RF energy was dissipated inside the fustrum where would the energy come from to create thrust? In all cases when energy is removed from a cavity the Q is reduced. What is it about the EM-Drive that makes this not the case? Isn't it another example where CoE is violated? Has anyone collected data from a functioning EM-Drive that shows this relation between Q and thrust?
There is no infinite Q as an anomalous skin depth effect results in losses even with superconducting cavities.
To accelerate, the small end directed reaction force generated as a result of unequal end plate radiation pressure needs to do work on the mass. The energy to do the work comes from the cavity energy, becoming another per cycle loss effect and reducing Q.
Let the mud fly!
"Performance also improves with the lowest order mode frequency"
So your theory predicts improved thrust for TM010, TE111, TM011, and TE011 over the often discussed TE013? Would TM010 have the greatest thrust since it is the lowest order mode?
It doesn't look like you've taken spherical end-caps into account. There is a significant difference in the internal volume when using spherical end-caps. I want to work up a FEKO model that incorporates your "ratio of the radii, Rb/Rs = 1.500." and "The length L should be no longer than Rs is wide, shorter is better and the performance improves as 1/L." Should I use flat or spherical end-caps?
My model uses a cylinder with flat end-caps. Spherical end caps should increase the Q and will increase the thrust, provided the differential dissipation is the same and favors the big end.
Regarding mode "shapes", I'm still mulling that over but the model says the lower the frequency and shorter the length, the better the performance, like a tapered pill-box.
Engineering reality says modes that have eddy currents crossing from end plate to side wall is a hard yakka build. Especially if the end plate needs to be removed to tune the coupler position. As Dave discovered, even what he thought was a good external solder seam around each end plate, had internally gaps and where the gaps were and eddy currents needed to flow, resulted in arching across the gap.
Exciting in TE01x mode eliminates end plate to side wall eddy currents and makes removable end plates possible.
Hi Todd,
Looking at your equation for T, am I correct in seeing the following geometric terms based on the radius? (1/L factor omitted below for clarity)
T ~ (R
b-R
s)*(R
s3/R
b3)
In your paper you mention that the optimal size ratio R
s/R
b=2/3.
Wouldn't a ratio of
Rs/Rb=3/4 result in a higher thrust? Or perhaps there are other factors not explicitly listed in the "T" approximation? (I'd reference an equation number, but I didn't see any
)
Let the mud fly!
"Performance also improves with the lowest order mode frequency"
So your theory predicts improved thrust for TM010, TE111, TM011, and TE011 over the often discussed TE013? Would TM010 have the greatest thrust since it is the lowest order mode?
It doesn't look like you've taken spherical end-caps into account. There is a significant difference in the internal volume when using spherical end-caps. I want to work up a FEKO model that incorporates your "ratio of the radii, Rb/Rs = 1.500." and "The length L should be no longer than Rs is wide, shorter is better and the performance improves as 1/L." Should I use flat or spherical end-caps?
My model uses a cylinder with flat end-caps. Spherical end caps should increase the Q and will increase the thrust, provided the differential dissipation is the same and favors the big end.
Regarding mode "shapes", I'm still mulling that over but the model says the lower the frequency and shorter the length, the better the performance, like a tapered pill-box.
Here an example with dimensions for a relative flat frustum and TE011 at 2.45GHz.
Todd, is this kind of design what you are talking about?
Rb/Rs=1.5
L <Rs
Exactly! Wow, that looks great. Thank you.
Edit: It reminds me of some UFO photos from the 70's. No?
Let the mud fly!
"Performance also improves with the lowest order mode frequency"
So your theory predicts improved thrust for TM010, TE111, TM011, and TE011 over the often discussed TE013? Would TM010 have the greatest thrust since it is the lowest order mode?
It doesn't look like you've taken spherical end-caps into account. There is a significant difference in the internal volume when using spherical end-caps. I want to work up a FEKO model that incorporates your "ratio of the radii, Rb/Rs = 1.500." and "The length L should be no longer than Rs is wide, shorter is better and the performance improves as 1/L." Should I use flat or spherical end-caps?
My model uses a cylinder with flat end-caps. Spherical end caps should increase the Q and will increase the thrust, provided the differential dissipation is the same and favors the big end.
Regarding mode "shapes", I'm still mulling that over but the model says the lower the frequency and shorter the length, the better the performance, like a tapered pill-box.
Engineering reality says modes that have eddy currents crossing from end plate to side wall is a hard yakka build. Especially if the end plate needs to be removed to tune the coupler position. As Dave discovered, even what he thought was a good external solder seam around each end plate, had internally gaps and where the gaps were and eddy currents needed to flow, resulted in arching across the gap.
Exciting in TE01x mode eliminates end plate to side wall eddy currents and makes removable end plates possible.
Hi Todd,
Looking at your equation for T, am I correct in seeing the following geometric terms based on the radius? (1/L factor omitted below for clarity)
T ~ (Rb-Rs)*(Rs3/Rb3)
In your paper you mention that the optimal size ratio Rs/Rb=2/3.
Wouldn't a ratio of Rs/Rb=3/4 result in a higher thrust? Or perhaps there are other factors not explicitly listed in the "T" approximation? (I'd reference an equation number, but I didn't see any )
Thanks, I know the paper needs work to be published. This feedback is what I'm looking for.
I ran a derivative optimization in MathCAD and the Maxima is at R
b/R
s = 1.5. 4/3 is smaller, and the thrust drops off quickly on the smaller side.
NOTE: I am still working on this. The equations are written "assuming" there is a frequency shift. However, Zeta could equally be interpreted as simply a loss of power at the same frequency. I don't see any means of distinguishing between them yet. All that is implied is that there is a gradient in the power dissipation, and Q helps to maximize the power dissipated AND the weight of the stored energy. My thinking is, that the power dissipated is going to balance the input power, and whatever the Loaded Q is under this condition, is what determines the steady state thrust.
Working on it...
Here an example with dimensions for a relative flat frustum and TE011 at 2.45GHz.
Todd, is this kind of design what you are talking about?
Rb/Rs=1.5
L <Rs
It seems notable that the geometries have been converging towards Shawyer's in more or less the same order, but we still lack cut and dry data that proves "yes, this works definitively and scales in this manner."
Hi Todd,
Looking at your equation for T, am I correct in seeing the following geometric terms based on the radius? (1/L factor omitted below for clarity)
T ~ (Rb-Rs)*(Rs3/Rb3)
In your paper you mention that the optimal size ratio Rs/Rb=2/3.
Wouldn't a ratio of Rs/Rb=3/4 result in a higher thrust? Or perhaps there are other factors not explicitly listed in the "T" approximation? (I'd reference an equation number, but I didn't see any )
https://www.researchgate.net/publication/308948407_EM_DRIVE_THEORY_-_GRAVITY_IN_A_CANYour equation goes like Co*
Rs^3*(Rb-Rs)/Rb^3/L where his equation goes: g~Co*
Rs^2*(Rb-Rs)/Rb^3/L
The difference would give you a different maximum when you take the df(Rs)/d(Rs)=0
Great work! Two more nitpicks inside the quotation marks, since my reader doesn't support more elaborate formatting...
1. Once again, simplify by "substituting", ωs~c0χm,nRs,
2. If the rate of decay at each end is asymmetrical, such that the big end absorbs and dissipates more power than the small end", t"he stored energy will have a tendency to "fall" toward the big end.
Since your model appears to rely on differential dissipation, could there be a double benefit by making the small side superconducting, and allowing the big side to do all of the dissipation?
Your 1/f relationship indicates the potential for more force in a smaller package by going to higher frequencies, holding the resonant mode shape constant. The trick is to keep the dissipating end cool through good heat transfer practices, and to produce the resonant mode at the smaller distance scale. Am I understanding your predictions correctly?
Once we have repeatable test setups with known error bounds, these predictions should be testable to confirm the validity of your model.
mh
I think you mean to use lower frequencies to maximize thrust/larger cavities. where g~1/f^2 or something like that. I think it seems similar to what Rodal was saying about using larger cavities to lower the frequency and maximize thrust. Both notsureofit's and WarpTech's math seem to have this.
I believe I may have been mistaken here. If I substitute 2/3*Rb=Rs in for Rs in Co^2*Rs^2*(Rb-Rs)/Rb^3/L then I get that the force isn't even dependent on the radius R and only 4*Co^2/(27*L) where L may determine resonant frequency. Smaller wavelengths leading to larger frequencies so your are correct I suppose. I am a little worried about the magnitude of force that could be present with the speed of light squared and wonder if it really applies.
Great work! Two more nitpicks inside the quotation marks, since my reader doesn't support more elaborate formatting...
1. Once again, simplify by "substituting", ωs~c0χm,nRs,
2. If the rate of decay at each end is asymmetrical, such that the big end absorbs and dissipates more power than the small end", t"he stored energy will have a tendency to "fall" toward the big end.
Since your model appears to rely on differential dissipation, could there be a double benefit by making the small side superconducting, and allowing the big side to do all of the dissipation?
Your 1/f relationship indicates the potential for more force in a smaller package by going to higher frequencies, holding the resonant mode shape constant. The trick is to keep the dissipating end cool through good heat transfer practices, and to produce the resonant mode at the smaller distance scale. Am I understanding your predictions correctly?
Once we have repeatable test setups with known error bounds, these predictions should be testable to confirm the validity of your model.
mh
I think you mean to use lower frequencies to maximize thrust/larger cavities. where g~1/f^2 or something like that. I think it seems similar to what Rodal was saying about using larger cavities to lower the frequency and maximize thrust. Both notsureofit's and WarpTech's math seem to have this.
I believe I may have been mistaken here. If I substitute 2/3*Rb=Rs in for Rs in Co^2*Rs^2*(Rb-Rs)/Rb^3/L then I get that the force isn't even dependent on the radius R and only 4*Co^2/(27*L) where L may determine resonant frequency. Smaller wavelengths leading to larger frequencies so your are correct I suppose. I am a little worried about the magnitude of force that could be present with the speed of light squared and wonder if it really applies.
When you compute the thrust, the c
2 cancels out the one in g, because we are using the weight of the energy as the mass, m = E/c
2, when multiplying m*g. So it's supposed to be there.
His paper being wrong is no more a matter of opinion than 1+1=2 being a matter of opinion.
I must admit that I've been skimming the thread a bit as of late due to the rate and volume of updates; have you gone into the specifics of the mistakes contained in the Woodward paper in prior posts?
Woodward's paper looks really bizarre. When he quite correctly arrives at a contradiction (even obviously wrong) with conservation of energy when he assumes constant thrust with constant power, he doesn't seem to even consider the possibility that it's because his theory just doesn't work.
It's not bizarre at all. Don't forget that the constant power is applied in the ship's frame where the velocity is always zero with respect to the instantaneous rest frame of concern. There is never an energy problem unless you wrongly and incoherently mix frames and demand the invariant input energy in the ship equals the kinetic energy in the observers frame which some here are doing.
...
And yes, doing it for a fixed 100W RF input would be best, since then I can estimate the gain in the cavity for a given input power.
Todd, there seems to be an issue regarding strong different energy density from big end to the other with such a design, at least for TE011. Using higher modes like TE012 or TE013 (or higher) the difference is much stronger as you can see if you take a look to my avatar pic.
This difference is even smaller when the frustum is flatter .
You can read the approx value for each region using the scale attached to the single field pics.
All other conditions like frequency, mode and so on is equal to
http://forum.nasaspaceflight.com/index.php?topic=40959.msg1596982#msg1596982
His paper being wrong is no more a matter of opinion than 1+1=2 being a matter of opinion.
I must admit that I've been skimming the thread a bit as of late due to the rate and volume of updates; have you gone into the specifics of the mistakes contained in the Woodward paper in prior posts?
Woodward's paper looks really bizarre. When he quite correctly arrives at a contradiction (even obviously wrong) with conservation of energy when he assumes constant thrust with constant power, he doesn't seem to even consider the possibility that it's because his theory just doesn't work.
Exactly.
I have specific criticisms scattered throughout a few posts, and Tellmeagain wrote a paper detailing the issues, which can be found here.
I'm sorry to have to say this but Tellmeagain's paper did not successfully deal with Woodward's paper in my opinion. I found errors and felt the conclusion was unduly harsh towards Woodward and his distinguished career.
...
And yes, doing it for a fixed 100W RF input would be best, since then I can estimate the gain in the cavity for a given input power.
Todd, there seems to be an issue regarding strong different energy density from big end to the other with such a design, at least for TE011. Using higher modes like TE012 or TE013 (or higher) the difference is much stronger as you can see if you take a look to my avatar pic.
This difference is even smaller when the frustum is flatter .
You can read the approx value for each region using the scale attached to the single field pics.
All other conditions like frequency, mode and so on is equal to http://forum.nasaspaceflight.com/index.php?topic=40959.msg1596982#msg1596982
Thanks for this! It's interesting none the less. @Rodal said that TM modes are easier to acquire, so maybe try a few of those. There is no magic sauce. The equation simply tells us that frequency is in the denominator. So the higher the frequency, the lower the thrust for a given set of dimensions. TE-011 is the lowest frequency mode, but other than a variable in the equation, there is nothing in my model that would predict the performance of each mode shape.
Great work! Two more nitpicks inside the quotation marks, since my reader doesn't support more elaborate formatting...
1. Once again, simplify by "substituting", ωs~c0χm,nRs,
2. If the rate of decay at each end is asymmetrical, such that the big end absorbs and dissipates more power than the small end", t"he stored energy will have a tendency to "fall" toward the big end.
Since your model appears to rely on differential dissipation, could there be a double benefit by making the small side superconducting, and allowing the big side to do all of the dissipation?
Your 1/f relationship indicates the potential for more force in a smaller package by going to higher frequencies, holding the resonant mode shape constant. The trick is to keep the dissipating end cool through good heat transfer practices, and to produce the resonant mode at the smaller distance scale. Am I understanding your predictions correctly?
Once we have repeatable test setups with known error bounds, these predictions should be testable to confirm the validity of your model.
mh
I think you mean to use lower frequencies to maximize thrust/larger cavities. where g~1/f^2 or something like that. I think it seems similar to what Rodal was saying about using larger cavities to lower the frequency and maximize thrust. Both notsureofit's and WarpTech's math seem to have this.
I believe I may have been mistaken here. If I substitute 2/3*Rb=Rs in for Rs in Co^2*Rs^2*(Rb-Rs)/Rb^3/L then I get that the force isn't even dependent on the radius R and only 4*Co^2/(27*L) where L may determine resonant frequency. Smaller wavelengths leading to larger frequencies so your are correct I suppose. I am a little worried about the magnitude of force that could be present with the speed of light squared and wonder if it really applies.
Has anyone built or proposed building a RF resonator using a higher frequency solid state source like a automotive radar Tx module? ( 77 GHz Transceiver, NXP Semiconductor PN MR2001-77) Power consumption is only 2.7 watts. Dimension and mass is small. It could be packaged on a custom PCB very precisely, & output measurement with integrated MEMS strain/force sensors for all non constrained axis. This lend itself to using very precise test & measurement equipment.
...
And yes, doing it for a fixed 100W RF input would be best, since then I can estimate the gain in the cavity for a given input power.
Todd, there seems to be an issue regarding strong different energy density from big end to the other with such a design, at least for TE011. Using higher modes like TE012 or TE013 (or higher) the difference is much stronger as you can see if you take a look to my avatar pic.
This difference is even smaller when the frustum is flatter .
You can read the approx value for each region using the scale attached to the single field pics.
All other conditions like frequency, mode and so on is equal to http://forum.nasaspaceflight.com/index.php?topic=40959.msg1596982#msg1596982
Thanks for this! It's interesting none the less. @Rodal said that TM modes are easier to acquire, so maybe try a few of those. There is no magic sauce. The equation simply tells us that frequency is in the denominator. So the higher the frequency, the lower the thrust for a given set of dimensions. TE-011 is the lowest frequency mode, but other than a variable in the equation, there is nothing in my model that would predict the performance of each mode shape.
Is there any way to combine your theory(equations) with
http://emdrive.wiki/@notsosureofit_Hypothesis ??
The mode shape/ field pattern should be considered because its essential for the energy density in the different regions of a truncated conical cavity with conductive walls.
OK to consider the energy density is more complicated than using this approximation formulas but it seems reasonable to involve this physical fact.
)