### Author Topic: EM Drive Developments - related to space flight applications - Thread 2  (Read 2519984 times)

#### Rodal

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##### Re: EM Drive Developments - related to space flight applications - Thread 2
« Reply #3540 on: 05/17/2015 02:17 PM »
....
Jose,

I am not arguing against my paper. You know may take. I am questioning your proof based on a functional form that has the mathematical properties I have shown. I know by myself, and I stated it in the draft, that here we are working with really small values. As you can see, I have not attempted any computation of a force, if any, or thrust. I am thinking about this and I am trying to work with real values. But please note also that this is a function of three independent variables: r1, r2 and U0.
Marco,

1) make a plot (you can sketch the geometry by hand with pencil and paper, scan it and post the image  ) of the geometry of the truncated cone you have in mind: clearly showing what you define to be r1, r2, h, and the z and r coordinates

2) explicitly show what is the optimal geometry of the truncated cone, as per your paper.

and then we can continue
« Last Edit: 05/17/2015 02:21 PM by Rodal »

#### StrongGR

##### Re: EM Drive Developments - related to space flight applications - Thread 2
« Reply #3541 on: 05/17/2015 02:28 PM »
....
Jose,

I am not arguing against my paper. You know may take. I am questioning your proof based on a functional form that has the mathematical properties I have shown. I know by myself, and I stated it in the draft, that here we are working with really small values. As you can see, I have not attempted any computation of a force, if any, or thrust. I am thinking about this and I am trying to work with real values. But please note also that this is a function of three independent variables: r1, r2 and U0.
Marco,

1) make a plot (you can sketch the geometry by hand with pencil and paper, scan it and post the image  ) of the geometry of the truncated cone you have in mind: clearly showing what you define to be r1, r2, h, and the z and r coordinates

2) explicitly show what is the optimal geometry of the truncated cone, as per your paper.

and then we can continue

I think you are completely off the target. What the heck we have to continue? You can choice r2>r1 and live happily with that or the other way around. Choose what you prefer and keep it. There is no claim to support here. It is also difficult for me to understand what you believe to have proven. There is no error there and you can do any computation you like with that. This is a real wasting of time.

#### txdrive

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##### Re: EM Drive Developments - related to space flight applications - Thread 2
« Reply #3542 on: 05/17/2015 02:33 PM »
We know from direct measurements that EM fields behave in a specific manner, down to parts per trillion. Momentum which is carried by an electromagnetic field can be measured directly as the field strength, with far greater precision. This knowledge puts a very low upper bound on the net momentum that EM fields can acquire and exchange with the cavity.

We also know that a high Q cavity of say 50,000 will do 50,000 bounces of the em field, each adding to the generated force. Shawyer's Force equation of (2 Po Df Q) / c clearly states Q is the way the EM Drive multiplies the very low force of one way to a much higher value.

Same effect used with laser thruster:
http://en.wikipedia.org/wiki/Photonic_laser_thruster
2/c, which is 6.6 uN/kW , times 50 000 , is 0.33 N/kW . Multiply by the bound on EM exchanging momentum with something unknown, a very small force (nanoNewtons). edit: typo.
« Last Edit: 05/17/2015 02:50 PM by txdrive »

#### Rodal

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##### Re: EM Drive Developments - related to space flight applications - Thread 2
« Reply #3543 on: 05/17/2015 02:38 PM »
...There is no claim to support here. It is also difficult for me to understand what you believe to have proven. There is no error there and you can do any computation you like with that. This is a real wasting of time.

Marco,

1) You wrote a very interesting paper, concluding that there is a geometry (I presume an optimal geometry) of a truncated cone that "comes to the rescue" which I assume it to mean that maximizes the General Relatvity effect in this cavity.

2) My proof, based on your paper shows that that optimal geometry is a cylinder with flat faces and negligible axial length.  The optimal geometry according to the equations in your paper being much closer to the Cannae cavity and the pillbox shape used by Dr. White than the geometry of a conical cavity.

3) What is the actual optimal geometry of the cavity to maximize the GR effect, according to your paper? I think that for you showing what is this optimal geometry would be great conclusion to your interesting paper.
« Last Edit: 05/17/2015 02:40 PM by Rodal »

#### StrongGR

##### Re: EM Drive Developments - related to space flight applications - Thread 2
« Reply #3544 on: 05/17/2015 02:42 PM »
....
Jose,

I am not arguing against my paper. You know may take. I am questioning your proof based on a functional form that has the mathematical properties I have shown. I know by myself, and I stated it in the draft, that here we are working with really small values. As you can see, I have not attempted any computation of a force, if any, or thrust. I am thinking about this and I am trying to work with real values. But please note also that this is a function of three independent variables: r1, r2 and U0.
Marco,

1) make a plot (you can sketch the geometry by hand with pencil and paper, scan it and post the image  ) of the geometry of the truncated cone you have in mind: clearly showing what you define to be r1, r2, h, and the z and r coordinates

2) explicitly show what is the optimal geometry of the truncated cone, as per your paper.

and then we can continue

I think you are completely off the target. What the heck we have to continue? You can choice r2>r1 and live happily with that or the other way around. Choose what you prefer and keep it. There is no claim to support here. It is also difficult for me to understand what you believe to have proven. There is no error there and you can do any computation you like with that. This is a real wasting of time.

Marco,

1) You wrote a very interesting paper, concluding that there is a geometry (I presume an optimal geometry) of a truncated cone that "comes to the rescue" which I assume it to mean that maximizes the General Relatvity effect in this cavity.

2) My proof, based on your paper shows that that optimal geometry is a cylinder with flat faces and negligible axial length.  The optimal geometry according to the equations in your paper being much closer to the Cannae cavity and the pillbox shape used by Dr. White than the geometry of a conical cavity.

3) What is the actual optimal geometry of the cavity to maximize the GR effect, according to your paper? I think that for you showing what is this optimal geometry would be great conclusion to your interesting paper.

But this is exactly what I am doing now to update my draft. Mathematica is running computing a realistic k with the values r1 and r2 taken from Minotti's paper. I need to estimate U0. In a few days I can give an answer to your question.

#### Notsosureofit

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##### Re: EM Drive Developments - related to space flight applications - Thread 2
« Reply #3545 on: 05/17/2015 02:47 PM »
Algebra aside, I believe what Eq. 37 should represent is the modification of L() such the terms w/ a and b give the amplitude of the observable sidebands outside of a frustum cavity as opposed to a cylindrical one. (I'm not yet to being able to comment on the correct expressions for a or b)

#### Rodal

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##### Re: EM Drive Developments - related to space flight applications - Thread 2
« Reply #3546 on: 05/17/2015 02:49 PM »
...
But this is exactly what I am doing now to update my draft. Mathematica is running computing a realistic k with the values r1 and r2 taken from Minotti's paper. I need to estimate U0. In a few days I can give an answer to your question.

Suggestion: to use the geometrical values used by Greg Egan  r1=2.5 cm, r2=10 cm, θw = 20° here: http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Cavity.html as Minotti quotes Egan's equations in Minotti's paper, and Egan shows explicit field solutions and the energy for those geometrical parameters.

#### TheTraveller

##### Re: EM Drive Developments - related to space flight applications - Thread 2
« Reply #3547 on: 05/17/2015 02:53 PM »
Does the Flight Thruster have a slightly concave top and convex bottom? Would appear so from the gaps.

Enhanced the photo as much as I can for those wishing to try to extract dimensions as this photo is better that the original as it has no distortion.

If we can find the dimension<M

The big end most certainly should be convex and the small end concave, relative from the outside of course. The big end and small end radii should not be coincidence but offset having the small end radius much larger than the big end. In fact, it might be better for the small end to be flat.

This is how Shawyer does it.

The end plate curve at each end should be the same radius as the curve of the em field as it expands outward. So not a flat wave front as some see but curved.

Which also means the curved wave front is always at right angles to the cone side walls as the wavelength increases as the cavity diameter increases, increasing the group velocity as well.

Shawyer did say the wave slides up and down the cavity walls and exerts no significant force on it. From this diagram, that seems to be the case. It does slide up and down the cavity walls, while always being at a right angle to it.

Then it hits one of the curved end plates and does a bounce back the other way.
It Is Time For The EmDrive To Come Out Of The Shadows

#### StrongGR

##### Re: EM Drive Developments - related to space flight applications - Thread 2
« Reply #3548 on: 05/17/2015 02:55 PM »
...
But this is exactly what I am doing now to update my draft. Mathematica is running computing a realistic k with the values r1 and r2 taken from Minotti's paper. I need to estimate U0. In a few days I can give an answer to your question.

Suggestion: to use the geometrical values used by Greg Egan  r1=2.5 cm, r2=10 cm, θw = 20° here: http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Cavity.html as Minotti quotes Egan's equations in Minotti's paper, and Egan shows explicit field solutions and the energy for those geometrical parameters.

I am using Minotti's values r1=18 cm and r2=36 cm and imposing boundary conditions one of which is P_n(cos(theta_0))=0.
« Last Edit: 05/17/2015 02:56 PM by StrongGR »

#### HypergolicSunrise

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##### Re: EM Drive Developments - related to space flight applications - Thread 2
« Reply #3549 on: 05/17/2015 02:59 PM »
I just want to throw this up here:
http://www.nature.com/ncomms/2014/140306/ncomms4300/full/ncomms4300.html
http://arxiv.org/ftp/arxiv/papers/1308/1308.0547.pdf

I think if you're looking in classical physics for answers, you won't find them.

#### TheTraveller

##### Re: EM Drive Developments - related to space flight applications - Thread 2
« Reply #3550 on: 05/17/2015 02:59 PM »
We know from direct measurements that EM fields behave in a specific manner, down to parts per trillion. Momentum which is carried by an electromagnetic field can be measured directly as the field strength, with far greater precision. This knowledge puts a very low upper bound on the net momentum that EM fields can acquire and exchange with the cavity.

We also know that a high Q cavity of say 50,000 will do 50,000 bounces of the em field, each adding to the generated force. Shawyer's Force equation of (2 Po Df Q) / c clearly states Q is the way the EM Drive multiplies the very low force of one way to a much higher value.

Same effect used with laser thruster:
http://en.wikipedia.org/wiki/Photonic_laser_thruster
2/c, which is 6.6 uN/kW , times 50 000 , is 0.33 N/kW . Multiply by the bound on EM exchanging momentum with something unknown, a very small force (nanoNewtons). edit: typo.

T = (2 * 100W * 50,000 Q * Df 0.5) / c = 16.6mN
It Is Time For The EmDrive To Come Out Of The Shadows

#### Rodal

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##### Re: EM Drive Developments - related to space flight applications - Thread 2
« Reply #3551 on: 05/17/2015 03:00 PM »
....

Shawyer did say the wave slides up and down the cavity walls and exerts no significant force on it. From this diagram, that seems to be the case. It does slide up and down the cavity walls, while always being at a right angle to it.
...
Greg Egan first considered the spherical ends, as a response to Shawyer's article with flat faces in the New Scientist article.

See http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Cavity.html where Greg Egan shows that the stresses on the inner conical surfaces are not negligible: following Maxwell's equations they exactly balance out the stresses on the spherical faces to end with zero net force on the EM Drive.

Did Shawyer publish a paper answering in detail the objections raised by Greg Egan's ?

#### StrongGR

##### Re: EM Drive Developments - related to space flight applications - Thread 2
« Reply #3552 on: 05/17/2015 03:07 PM »
....

Shawyer did say the wave slides up and down the cavity walls and exerts no significant force on it. From this diagram, that seems to be the case. It does slide up and down the cavity walls, while always being at a right angle to it.
...
Greg Egan first considered the spherical ends, as a response to Shawyer's article with flat faces in the New Scientist article.

See http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Cavity.html where Greg Egan shows that the stresses on the inner conical surfaces are not negligible: following Maxwell's equations they exactly balance out the stresses on the spherical faces to end with zero net force on the EM Drive.

Did Shawyer publish a paper answering in detail the objections raised by Greg Egan's ?

I have that link constantly open and all the results, well almost all, are in the Minotti's paper. The point is that Shawyer never answered a single question put out by the community, being Egan or whoever else. Most of them think he is a charlatan.

#### TheTraveller

##### Re: EM Drive Developments - related to space flight applications - Thread 2
« Reply #3553 on: 05/17/2015 03:12 PM »
....

Shawyer did say the wave slides up and down the cavity walls and exerts no significant force on it. From this diagram, that seems to be the case. It does slide up and down the cavity walls, while always being at a right angle to it.
...
Greg Egan first considered the spherical ends, as a response to Shawyer's article with flat faces in the New Scientist article.

See http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Cavity.html where Greg Egan shows that the stresses on the inner conical surfaces are not negligible: following Maxwell's equations they exactly balance out the stresses on the spherical faces to end with zero net force on the EM Drive.

Did Shawyer publish a paper answering in detail the objections raised by Greg Egan's ?

How can an EM wave, acting at a right angle with the surface it is in contact with, exert any force on it? Did Egan use a flat wave front or a curved wave front at 90 deg to the side cavity wall for the interaction force?

Why would Shawyer object to what Egan wrote? Shawyer is not a theoretical guy, not in the business of theory point scoring or needs to publish or die. He is working from measured data from a device that produces thrust and the level of that thrust matches the equations he created to model it.

Shawyer published this measured thrust as did the Chinese and why they think it does what it does. Someone who publishes a paper claiming it can't work because of their theory, just might be politely ignored as they get on with business.

« Last Edit: 05/17/2015 03:24 PM by TheTraveller »
It Is Time For The EmDrive To Come Out Of The Shadows

#### TheTraveller

##### Re: O09
« Reply #3554 on: 05/17/2015 03:21 PM »
Does the Flight Thruster have a slightly concave top and convex bottom? Would appear so from the gaps.

Enhanced the photo as much as I can for those wishing to try to extract dimensions as this photo is better that the original as it has no distortion.

If we can find the dimension<M

The big end most certainly should be convex and the small end concave, relative from the outside of course. The big end and small end radii should not be coincidence but offset having the small end radius much larger than the big end. In fact, it might be better for the small end to be flat.

If either end is flat, the bounce will introduce very significant phase distortion into the returning curved wave. For me it is hard to see that Shawyer ever used flat end plates INSIDE the cavity. As we never saw inside the cavity, what is to say he didn't use curved end plates inside and flat end covers outside? What he drew may not be what he built.
« Last Edit: 05/17/2015 03:27 PM by TheTraveller »
It Is Time For The EmDrive To Come Out Of The Shadows

#### Rodal

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##### Re: EM Drive Developments - related to space flight applications - Thread 2
« Reply #3555 on: 05/17/2015 03:25 PM »
...
Shawyer published this measured thrust as did the Chinese and why they think it does what it does. Someone who publishes a paper claiming it can't work because of their theory, just might be politely ignored as they get on with business.
Greg Egan did not claim  that the EM Drive cannot work because of a theory invented by Greg Egan.

It is not his theory.  Greg Egan is showing again a well-known result.

Instead, Greg Egan showed an already known-proof that the stresses due to standing waves on the inner walls of a resonating cavity of any arbitrary shape whatsoever perfectly balance, and therefore there is zero net force in any direction, according to Maxwell's equations.

There are some ways out of this that have been discussed in this thread.  The curious thing to me is that Shawyer appears to be the only one still stating that the EM Drive can accelerate by itself just using Maxwell's equations and Special Relativity.
« Last Edit: 05/17/2015 03:36 PM by Rodal »

#### StrongGR

##### Re: EM Drive Developments - related to space flight applications - Thread 2
« Reply #3556 on: 05/17/2015 03:31 PM »
...
Shawyer published this measured thrust as did the Chinese and why they think it does what it does. Someone who publishes a paper claiming it can't work because of their theory, just might be politely ignored as they get on with business.
Greg Egan did not claim  that the EM Drive cannot work because of a theory invented by Greg Egan.

It is not his theory.  Greg Egan is showing again a well-known result.

Instead, Greg Egan showed again, an already known-proof that the stresses due to standing waves on the inner walls of a resonating cavity of any arbitrary shape whatsoever perfectly balance, and therefore there is zero net force in any direction, according to Maxwell's equations.

Egan exploited the computations of what the community only stated: Momentum is not conserved and so this does not work. This is the reason why we are looking elsewhere than only Maxwell equations.

#### TheTraveller

##### Re: EM Drive Developments - related to space flight applications - Thread 2
« Reply #3557 on: 05/17/2015 03:31 PM »
...
Shawyer published this measured thrust as did the Chinese and why they think it does what it does. Someone who publishes a paper claiming it can't work because of their theory, just might be politely ignored as they get on with business.
Greg Egan did not claim  that the EM Drive cannot work because of a theory invented by Greg Egan.  Instead, Greg Egan showed again, a known-proof that the stresses on the inner walls of a resonating cavity of any arbitrary shape whatsoever (as long as it is closed) perfectly balance, and therefore there is zero net force in any direction, according to Maxwell's equations.

If you can, please answer my simple question:

How can a curved EM wave, as in the attachment, touching the cavity wall at right angles to the wall, cause any force to be generated on the wall?
It Is Time For The EmDrive To Come Out Of The Shadows

#### Rodal

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##### Re: EM Drive Developments - related to space flight applications - Thread 2
« Reply #3558 on: 05/17/2015 03:34 PM »
...
Shawyer published this measured thrust as did the Chinese and why they think it does what it does. Someone who publishes a paper claiming it can't work because of their theory, just might be politely ignored as they get on with business.
Greg Egan did not claim  that the EM Drive cannot work because of a theory invented by Greg Egan.  Instead, Greg Egan showed again, a known-proof that the stresses on the inner walls of a resonating cavity of any arbitrary shape whatsoever (as long as it is closed) perfectly balance, and therefore there is zero net force in any direction, according to Maxwell's equations.

If you can, please answer my simple question:

How can a curved EM wave, as in the attachment, touching the cavity wall at right angles to the wall, cause any force to be generated on the wall?

Because the solution of Maxwell's differential equations with the appropriate Boundary Conditions demand so.

An EM wave that causes no stresses on the conical inner surfaces does NOT satisfy the boundary conditions.
« Last Edit: 05/17/2015 03:36 PM by Rodal »

#### StrongGR

##### Re: EM Drive Developments - related to space flight applications - Thread 2
« Reply #3559 on: 05/17/2015 03:34 PM »
...
Shawyer published this measured thrust as did the Chinese and why they think it does what it does. Someone who publishes a paper claiming it can't work because of their theory, just might be politely ignored as they get on with business.
Greg Egan did not claim  that the EM Drive cannot work because of a theory invented by Greg Egan.  Instead, Greg Egan showed again, a known-proof that the stresses on the inner walls of a resonating cavity of any arbitrary shape whatsoever (as long as it is closed) perfectly balance, and therefore there is zero net force in any direction, according to Maxwell's equations.

If you can, please answer my simple question:

How can a curved EM wave, as in the attachment, touching the cavity wall at right angles to the wall, cause any force to be generated on the wall?

You cannot stare at a pictorial representation claiming something is there. Physics means mathematics and mathematics, through Maxwell equations, says no net momentum.

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