Author Topic: EM Drive Developments Thread 1  (Read 765670 times)

Online Rodal

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Re: EM Drive Developments
« Reply #1840 on: 10/09/2014 09:51 PM »
The dielectric is clearly visible as a small flat douhgnut (a disk with a central hole) in these pictures of the Electric Field for their future truncated cone.  The NASA researchers think that it is best located at the small flat surface.
« Last Edit: 10/09/2014 09:57 PM by Rodal »

Offline RotoSequence

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Re: EM Drive Developments
« Reply #1841 on: 10/09/2014 09:59 PM »
The dielectric is clearly visible as a small flat douhgnut (a disk with a central hole) in these pictures of the Electric Field for their future truncated cone.  The NASA researchers think that it is best located at the small flat surface.

All the more reason to try to break it and see if it breaks as anticipated. :)

Offline Mulletron

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Re: EM Drive Developments
« Reply #1842 on: 10/09/2014 10:00 PM »
The dielectric is clearly visible as a small flat douhgnut (a disk with a central hole) in these pictures of the Electric Field for their future truncated cone.  The NASA researchers think that it is best located at the small flat surface.

Given what we (think) we know now. That is the worst place to put it. I'm drawing a pic now. Using this guy's info as a ref in transverse E and the right hand rule.

http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Cavity.html


Edit:

I don't even need to draw it. Just scroll down where you see the three TE modes. Place imaginary dielectric in the right places (max H) and with the right orientation. Then cross fingers.
« Last Edit: 10/09/2014 10:05 PM by Mulletron »
Challenge your preconceptions, or they will challenge you. - Velik

Online Rodal

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Re: EM Drive Developments
« Reply #1843 on: 10/09/2014 10:02 PM »
The magnetic field in the truncated cone is in blue  Observe that the magnetic field is directed along the axis of revolution of the truncated cone, while the electric field is in red and it circulates along two main cells of different rotational sign, clockwise and counterclockwise:
« Last Edit: 10/09/2014 10:04 PM by Rodal »

Offline Mulletron

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Re: EM Drive Developments
« Reply #1844 on: 10/09/2014 10:06 PM »
The magnetic field in the truncated cone is in blue  Observe that the magnetic field is directed along the axis of revolution of the truncated cone, while the electric field is in red and it circulates along two main cells of different rotational sign, clockwise and counterclockwise:

Yep you got it. There's your differences in angular and linear momentum too.


Given the placement of the dielectric between Cannae and Shawyer, Cannae got it more correct. Guess that's why they are pretty close. Shawyer had a better shape, Cannae had a better dielectric setup.
« Last Edit: 10/09/2014 10:11 PM by Mulletron »
Challenge your preconceptions, or they will challenge you. - Velik

Online Rodal

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Re: EM Drive Developments
« Reply #1845 on: 10/09/2014 10:11 PM »
The magnetic field in the truncated cone is in blue  Observe that the magnetic field is directed along the axis of revolution of the truncated cone, while the electric field is in red and it circulates along two main cells of different rotational sign, clockwise and counterclockwise:

Yep you got it. There's your differences in angular and linear momentum too.

Observe that the magnetic field arrows point away from both surfaces, towards the middle of the truncated cone, but it is stronger emanating from the larger surface, so the neutral point is closer towards the small surface
« Last Edit: 10/09/2014 10:13 PM by Rodal »

Offline Mulletron

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Re: EM Drive Developments
« Reply #1846 on: 10/09/2014 10:14 PM »
The magnetic field in the truncated cone is in blue  Observe that the magnetic field is directed along the axis of revolution of the truncated cone, while the electric field is in red and it circulates along two main cells of different rotational sign, clockwise and counterclockwise:

Yep you got it. There's your differences in angular and linear momentum too.

Observe that the magnetic field arrows point away from both surfaces, towards the center of the truncated cone.

They are counter rotation circles in the vertical axis, meeting in the center. The magnetic flux flows like water down a drain, because the whole rf field has a rotation, and the direction of the poynting vector.
« Last Edit: 10/09/2014 10:31 PM by Mulletron »
Challenge your preconceptions, or they will challenge you. - Velik

Online Rodal

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Re: EM Drive Developments
« Reply #1847 on: 10/09/2014 10:27 PM »
The magnetic field in the truncated cone is in blue  Observe that the magnetic field is directed along the axis of revolution of the truncated cone, while the electric field is in red and it circulates along two main cells of different rotational sign, clockwise and counterclockwise:

Yep you got it. There's your differences in angular and linear momentum too.

Observe that the magnetic field arrows point away from both surfaces, towards the center of the truncated cone.

They are counter rotation circles in the vertical axis, meeting in the center. The magnetic flux flows like water down a drain, because the whole rf field has a rotation.

but it is stronger emanating from the larger surface, so the neutral point is closer towards the small surface

Offline Mulletron

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Re: EM Drive Developments
« Reply #1848 on: 10/09/2014 10:41 PM »
Areas of max H flow in poynting vector. Wonder which one would be best?

A separate issue just realized is if this resolves the Q discrepancy on page 18 for the TM mode, the dielectric was probably in a magnetic null zone.

Sure hope that arxiv paper http://arxiv-web3.library.cornell.edu/abs/1404.5990 on momentum is correct and applicable.

I still haven't gotten around to looking at how chiral PTFE is along x, y, z axis.
« Last Edit: 10/09/2014 11:48 PM by Mulletron »
Challenge your preconceptions, or they will challenge you. - Velik

Online Rodal

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Re: EM Drive Developments
« Reply #1849 on: 10/09/2014 10:42 PM »
Diamagnetism calculations
MIT Course 6.763 2003 Lecture 8

http://web.mit.edu/6.763/www/FT03/Lectures/Lecture8.pdf

Offline Mulletron

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Re: EM Drive Developments
« Reply #1850 on: 10/09/2014 11:27 PM »
This is important:
Please fact check me on this but of the three TM modes on this http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Cavity.html page; the one closest resembling TM211 would be this one right? At least good enough for a rough model? I think so. Not exactly but close enough because what I'm really interested in are the position of transverse H with respect to Z. The view is of the Z axis running vertically so the blue magnetic X, and Y are just dots and crosses.

I can see how highly frequency dependent and sensitive this mode is, which accounts for the big difference in Q and thrust with just a small change in frequency. Given the small size of the dielectric slug in the vertical axis at the small end, the resonant mode would very easily dip into and out of the dielectric with very small freq changes. Hence the loss of thrust. A COMSOL plot is needed for 1932.6 and 1936.7 to see this. I need to see if the magnetic field lines were in the dielectric more or less with both freqs.

At 1932.6, Q was down but thrust was up. Very telling indeed.

If I'm right, then eureka!
« Last Edit: 10/18/2014 10:30 AM by Mulletron »
Challenge your preconceptions, or they will challenge you. - Velik

Online Rodal

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Re: EM Drive Developments
« Reply #1851 on: 10/09/2014 11:43 PM »
This is important:
Please fact check me on this but of the three TM modes on this http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Cavity.html page; the one closest resembling TM211 would be this one right? At least good enough for a rough model? I think so. Not exactly but close enough because what I'm really interested in are the position of transverse H with respect to Z. The view is of the Z axis running vertically so the blue magnetic X, and Y are just dots and crosses.

I can see how highly frequency dependent and sensitive this mode is, which accounts for the big difference in Q and thrust with just a small change in frequency. Given the small size of the dielectric slug in the vertical axis at the small end, the resonant mode would very easily dip into and out of the dielectric with very small freq changes. Hence the loss of thrust. A COSMOL plot is needed for 1932.6 and 1936.7 to see this. I need to see if the magnetic field lines were in the dielectric more or less with both freqs.

At 1932.6, Q was down but thrust was up. Very telling indeed.

If I'm right, then eureka!

Answer: none of the modes calculated in the closed-form solution by Greg Egan here: http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Cavity.html



agree with the modes calculated by COMSOL Finite Element analysis as presented by Brady et.al. (shown with red arrows in the attachment below).

The first Transverse Electric mode shown by Egan has a single cell along the cone's axis of revolution.
The mode calculated by COMSOL Brady et.al. has two cells along the cone's axis of revolution.

The second Transverse Electric mode shown by Egan has two cells, but they are distributed in a completely different fashion: the smaller cell is closest to the large transverse surface while the mode calculated by COMSOL shows the smaller cell closest to the smaller transverse surface.

It is not clear why this is so.  It could be because of the boundary conditions.  I have a strong suspicion that the reason is due to the cylinder inside the truncated cone shown in pink red here:

When I have time I may model it with Mathematica and see what's going on but I don't have free time to do that during the next couple of weeks.

 
« Last Edit: 10/09/2014 11:53 PM by Rodal »

Offline DIYFAN

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Re: EM Drive Developments
« Reply #1852 on: 10/09/2014 11:50 PM »
This is important:
Please fact check me on this but of the three TM modes on this http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Cavity.html page; the one closest resembling TM211 would be this one right? At least good enough for a rough model? I think so. Not exactly but close enough because what I'm really interested in are the position of transverse H with respect to Z. The view is of the Z axis running vertically so the blue magnetic X, and Y are just dots and crosses.

Without speaking specifically to your observation, the shape matches fairly closely the cavity in Shawyer's most recent patent disclosure (with parabolic ends):
http://worldwide.espacenet.com/publicationDetails/biblio?DB=EPODOC&II=0&ND=3&adjacent=true&locale=en_EP&FT=D&date=20130206&CC=GB&NR=2493361A&KC=A

Offline Mulletron

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Re: EM Drive Developments
« Reply #1853 on: 10/09/2014 11:51 PM »
Yeah Egan's modes are being used as generic representations. I only care about the last number here. TM211, TMXYZ. I only care about Z because X and Y follow Z. Do you see how increasing and decreasing the frequency fills the void of the cavity more or less? That's what I'm getting at. The cells get smaller with higher frequency and change shape. At a critical point when increasing frequency, you get a brand new mode by adding a cell. This is pretty intuitive. Mostly because I know radars really well. You can't see it exactly without a plot.
« Last Edit: 10/09/2014 11:57 PM by Mulletron »
Challenge your preconceptions, or they will challenge you. - Velik

Offline Notsosureofit

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Re: EM Drive Developments
« Reply #1854 on: 10/09/2014 11:55 PM »
This is important:
Please fact check me on this but of the three TM modes on this http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Cavity.html page; the one closest resembling TM211 would be this one right? At least good enough for a rough model? I think so. Not exactly but close enough because what I'm really interested in are the position of transverse H with respect to Z. The view is of the Z axis running vertically so the blue magnetic X, and Y are just dots and crosses.

I can see how highly frequency dependent and sensitive this mode is, which accounts for the big difference in Q and thrust with just a small change in frequency. Given the small size of the dielectric slug in the vertical axis at the small end, the resonant mode would very easily dip into and out of the dielectric with very small freq changes. Hence the loss of thrust. A COSMOL plot is needed for 1932.6 and 1936.7 to see this. I need to see if the magnetic field lines were in the dielectric more or less with both freqs.

At 1932.6, Q was down but thrust was up. Very telling indeed.

If I'm right, then eureka!

Answer: none of the modes calculated in the closed-form solution by Greg Egan here: http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Cavity.html



agree with the modes calculated by COMSOL Finite Element analysis as presented by Brady et.al. (shown with red arrows in the attachment below).

The first Transverse Electric mode shown by Egan has a single cell along the cone's axis of revolution.
The mode calculated by COMSOL Brady et.al. has two cells along the cone's axis of revolution.

The second Transverse Electric mode shown by Egan has two cells, but they are distributed in a completely different fashion: the smaller cell is closest to the large transverse surface while the mode calculated by COMSOL shows the smaller cell closest to the smaller transverse surface.

It is not clear why this is so.  It could be because of the boundary conditions.  I have a strong suspicion that the reason is due to the cylinder inside the truncated cone shown in pink red here:

When I have time I may model it with Mathematica and see what's going on but I don't have free time to do that during the next couple of weeks.

 

If the small end is filled w/ dielectric that would make the difference, the optical length is greater for the same physical length.  Teflon n ~ 2
« Last Edit: 10/09/2014 11:56 PM by Notsosureofit »

Online Rodal

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Re: EM Drive Developments
« Reply #1855 on: 10/09/2014 11:55 PM »
Yeah Egan's modes are being used as generic representations. I only care about the last number here. Do you see how increasing and decreasing the frequency fills the void of the cavity more or less? That's what I'm getting at. The cells get smaller with higher frequency and change shape. You can't see it exactly without a plot.
Sorry, to me they are completely different mode shapes, as I wrote above.  Again, I think that the Egan solution is inapplicable mainly because of the pink-red cylinder inside the truncated cone and to a much lesser extent because of the flat surfaces.

Online Rodal

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Re: EM Drive Developments
« Reply #1856 on: 10/09/2014 11:57 PM »
This is important:
Please fact check me on this but of the three TM modes on this http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Cavity.html page; the one closest resembling TM211 would be this one right? At least good enough for a rough model? I think so. Not exactly but close enough because what I'm really interested in are the position of transverse H with respect to Z. The view is of the Z axis running vertically so the blue magnetic X, and Y are just dots and crosses.

I can see how highly frequency dependent and sensitive this mode is, which accounts for the big difference in Q and thrust with just a small change in frequency. Given the small size of the dielectric slug in the vertical axis at the small end, the resonant mode would very easily dip into and out of the dielectric with very small freq changes. Hence the loss of thrust. A COSMOL plot is needed for 1932.6 and 1936.7 to see this. I need to see if the magnetic field lines were in the dielectric more or less with both freqs.

At 1932.6, Q was down but thrust was up. Very telling indeed.

If I'm right, then eureka!

Answer: none of the modes calculated in the closed-form solution by Greg Egan here: http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Cavity.html



agree with the modes calculated by COMSOL Finite Element analysis as presented by Brady et.al. (shown with red arrows in the attachment below).

The first Transverse Electric mode shown by Egan has a single cell along the cone's axis of revolution.
The mode calculated by COMSOL Brady et.al. has two cells along the cone's axis of revolution.

The second Transverse Electric mode shown by Egan has two cells, but they are distributed in a completely different fashion: the smaller cell is closest to the large transverse surface while the mode calculated by COMSOL shows the smaller cell closest to the smaller transverse surface.

It is not clear why this is so.  It could be because of the boundary conditions.  I have a strong suspicion that the reason is due to the cylinder inside the truncated cone shown in pink red here:

When I have time I may model it with Mathematica and see what's going on but I don't have free time to do that during the next couple of weeks.

 

If the smll end is filled w/ dielectric that would make the difference, the optical length is greater for the same physical length

No, I don't think that it is the dielectric.  The mode shapes are due to the geometrical boundary conditions, and the boundary condition inside is of a cylinder 

Online Rodal

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Re: EM Drive Developments
« Reply #1857 on: 10/09/2014 11:58 PM »
It is incorrect to think that it is a truncated cone on the inside.  Everything shows that it is a cylinder on one end joined to a truncated cone on the other end.  The mode shapes for such a geometric body are different than the mode shapes for a truncated cone as modeled by Egan.

And I don't think that the cylinder is there by accident. Somebody thought this through.
« Last Edit: 10/10/2014 12:00 AM by Rodal »

Offline aero

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Re: EM Drive Developments
« Reply #1858 on: 10/10/2014 12:00 AM »
I made up an illustration showing the general character of dark matter thrust resulting from the varying inertia within the cavity. I need to have some data before putting numbers to the thrust, maybe someone else is curious enough to do that. I'm happy that the thrust points in the right direction. See the text on my drawing for my explanation.
Retired, working interesting problems

Offline Mulletron

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Re: EM Drive Developments
« Reply #1859 on: 10/10/2014 12:04 AM »
It is incorrect to think that it is a truncated cone on the inside.  Everything shows that it is a cylinder on one end joined to a truncated cone on the other end.  The mode shapes for such a geometric body are different than the mode shapes for a truncated cone as modeled by Egan.

And I don't think that the cylinder is there by accident. Somebody thought this through.


Yeah it looks like they put a can inside the cone for some reason. Good eye. Still I wanna see those modes.
« Last Edit: 10/10/2014 12:05 AM by Mulletron »
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