Author Topic: EM Drive Developments - related to space flight applications - Thread 3  (Read 1875387 times)

Offline TheTraveller

I went outside for a walk and I found out that actually:


(Group velocity*Electric Permitivity of Free space)*(Phase velocity*Magnetic Permeability of Free space)  = 1

(all these multiplied together give exactly one)

How about that?

great, but not the least bit surprising as vg * vp = c2 and eo * muo = 1/c2

Of course, it was a contrived attempt at humor answering these posts concerning somebody posting several posts remaking the well known fact that it is not the least beat surprising that 2c is not the same thing as c^2 (unless c=2): :)

Have you considered going outside and walking around a bit? LOL
Phase velocity + group velocity = 2c.
Wrong

Group velocity X phase velocity = 2c.
Also wrong

Real issue is information, energy & momentum travels in a waveguide at group velocity, below 1c and not at phase velocity, above 1c as some have claimed. Would be nice if momentum travelled at phase velocity, above 1c, as it bounced off the end plate but it doesn't.
« Last Edit: 07/10/2015 11:52 AM by TheTraveller »
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Offline TheTraveller

Shawyer's theory of how cavity acceleration generates asymmetric Force is attached as an image:

Please review sections 1, 2 & 3 of the IAC 2013 paper as attached for more details.

Quote
The Q factor of the cavity is defined as the stored energy divided by the energy lost per cycle.

Thus as stored energy is transferred to kinetic energy, the decrease in stored energy results in a decrease in Q factor.

Thus as acceleration increases, Q decreases and thus thrust decreases.

The performance of superconducting thrusters was predicted using this simple energy theory, but without identifying the actual mechanism.

This paper corrects this situation by describing the Doppler shifts which cause a decrease in stored energy, but which, more importantly, cause the frequency of the propagating wave to move outside the narrow resonant bandwidth of the cavity.

Basically cavity acceleration causes asymmetric resonant wave path length variation that causes either MOTOR mode or GENERATOR mode operation. No acceleration, no asymmetric resonant wave path length variation and the cavity is in IDLE mode.
« Last Edit: 07/10/2015 12:31 PM by TheTraveller »
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.
Herman Melville, Moby Dick

Offline TheTraveller

Shawyer's theory of how cavity acceleration generates asymmetric Force is attached as an image:

Please review sections 1, 2 & 3 of the IAC 2013 paper as attached for more details.

...
I'm curious as to why you are attaching images of a text page of the report that you also attach as a pdf. Attaching an image of the text page takes more of your time, and more bandwidth, while the text information in the image is already in the pdf you attach.  If it is to call attention to a particular section, you already detail that in your message ("Please review sections 1, 2 & 3")

Simple.

People look at / read images more than they download and read the attached paper.
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.
Herman Melville, Moby Dick

Offline Rodal

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..
Basically cavity acceleration causes asymmetric resonant wave path length variation that causes either MOTOR mode or GENERATOR mode operation. No acceleration, no asymmetric resonant wave path length variation and the cavity is in IDLE mode.
So you are saying that the EM Drive needs to be accelerated by other means, in order to itself engage in "motor" mode and produce any acceleration.

But the EM Drive in Shawyer's and other researcher's experiments is located on a rotating Earth that is experiencing centripetal acceleration:  0.034 m/s^2 near the Equator , (and a centripetal acceleration around the Sun of  0.005928 m/s^2)

Why isn't the centripetal acceleration of the Earth enough to cause the "motor" mode to engage?

How much threshold acceleration is required for the "motor" mode to engage and what is this acceleration threshold value based on, or due to?
« Last Edit: 07/10/2015 01:11 PM by Rodal »

Offline TheTraveller

..
Basically cavity acceleration causes asymmetric resonant wave path length variation that causes either MOTOR mode or GENERATOR mode operation. No acceleration, no asymmetric resonant wave path length variation and the cavity is in IDLE mode.
So you are saying that the EM Drive needs to be accelerated by other means, in order to itself engage in "motor" mode and produce any acceleration.

But the EM Drive in Shawyer's and other researcher's experiments is located on a rotating Earth that is experiencing centripetal acceleration:  0.034 m/s^2 near the Equator , (and a centripetal acceleration around the Sun of  0.005928 m/s^2)

Why isn't the centripetal acceleration of the Earth enough to cause the "motor" mode to engage?

How much acceleration is required for the "motor" mode to engage and what is this acceleration value based on, or due to?

Could say the same thing about a can of Coke and the Coke fluid inside it.

Will the Coke can accelerate relative to the fluid inside it without an external accelerative Force being applied to the Can? Of course it will not.
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.
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Offline Rodal

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Neither a Coke can, nor the fluid inside it have a "motor" mode or a "generator" mode that are triggered by acceleration.  Nobody to my knowledge has posited to use a Coke can as a means of space propulsion.

The questions:

1) Why isn't the centripetal acceleration of the Earth enough to cause the conjectured "motor" mode of an EM Drive to engage?

2) How much threshold acceleration is required for the "motor" mode to engage and what is this acceleration threshold value based on, or due to?

are not answered by substituting an analogy of the EM Drive to a Coke can with a fluid inside it.

I guess that there is no answer to the above questions at the moment.
« Last Edit: 07/10/2015 01:22 PM by Rodal »

Offline ElizabethGreene

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Last night I read:
Wimmer, M., Regensburger, A., Bersch, C., Miri, M., Batz, S., Onishchukov, G., & ... Peschel, U. (2013). Optical diametric drive acceleration through action-reaction symmetry breaking. Nature Physics, 9(12), 780-784. doi:10.1038/nphys2777

Two sentence summary: Photon-Photon interactions in clever devices are predicted and observed to break Newton's third law Symmetry.  I.e. S1 collides with S2 and both end up traveling in the same direction and velocity as S1's original vector.

If S2 is trapped bouncing off of the end plate of your resonator and a steady stream of input energy S1, then it isn't difficult to imagine this broken symmetry leading to a violation of Conservation of Momentum.

If your library has ebscohost you can get the paper free.  If you don't have access, PM me.

Are there other examples of broken symmetries?

Offline TheTraveller

Neither a Coke can, nor the fluid inside it have a "motor" mode or a "generator" mode that are triggered by acceleration.  Nobody to my knowledge has posited to use a Coke can as a means of space propulsion.

The questions:

1) Why isn't the centripetal acceleration of the Earth enough to cause the conjectured "motor" mode of an EM Drive to engage?

2) How much threshold acceleration is required for the "motor" mode to engage and what is this acceleration threshold value based on, or due to?

are not answered by substituting an analogy of the EM Drive to a Coke can with a fluid inside it.

I guess that there is no answer to the above questions at the moment.

1) Both the EM energy inside the EMDrive and the cavity experience the same centripetal acceleration of the Earth, just as does the Coke can and the Coke fluid inside it.

2) I don't know how much initial acceleration is required to trigger MOTOR mode. Suggest it is not much as vibration can trigger it.
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Offline rfmwguy

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The extremely high Q claimed for the Chinese and other em-drive cavities is completely wrong.  I have already showed they are not calculating Q correctly.   The graph shown is not a photo taken from a network analyzer and so I believe it is just made up data.   These cavities are similar in most respects to cavity filters used for VHF and UHF repeaters.   A 145 MHz cavity typically has a Q = 350.   Scaling this up to 2.5 GHz and the Q may be as high as 1,000 - 2,000.  The skin effect and other factors increase the losses at higher frequencies.

So easy to claim the Chinese data has been made up, despite having no proof. Along with silly claims that would also say Eagleworks doesn't know how to measure Q either as per attached measured Q of 50,995.

I'll not bother to send you my data as you will claim it is also made up.
You guys are in my world when you talk Q, and yes, I've used $100K network analyzers and handhelds. Here's the deal...A Q of 10K is theoretically possible but highly unlikely. A 2.45 Ghz bandpass cavity would have to have a 3dB (half power BW) of 245 Khz...I've never seen such a beast. Here's the problem...center frequency drift of both the cavity and the source. You'd be chasing your tail trying to keep it centered.

I'm for projecting Qs of this design between 1 and 5K, meaning between about 2 & 5 Mhz 3dB BW. Even at this reduced Q, there will be drift concerns due to heating.

Bottom line, Qs are not 5 digits. On paper, yes...real world, no.

Offline birchoff

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Has anyone seen this paper yet. I am wondering if this is the paper @Traveller was talking about some pages back.

http://www.sciencedirect.com/science/article/pii/S0094576515002726


Offline Rodal

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Last night I read:
Wimmer, M., Regensburger, A., Bersch, C., Miri, M., Batz, S., Onishchukov, G., & ... Peschel, U. (2013). Optical diametric drive acceleration through action-reaction symmetry breaking. Nature Physics, 9(12), 780-784. doi:10.1038/nphys2777

Two sentence summary: Photon-Photon interactions in clever devices are predicted and observed to break Newton's third law Symmetry.  I.e. S1 collides with S2 and both end up traveling in the same direction and velocity as S1's original vector.

If S2 is trapped bouncing off of the end plate of your resonator and a steady stream of input energy S1, then it isn't difficult to imagine this broken symmetry leading to a violation of Conservation of Momentum.

If your library has ebscohost you can get the paper free.  If you don't have access, PM me.

Are there other examples of broken symmetries?

Here is a shorter Power Point presentation they made:

http://blogs.df.ufpe.br/~lightmatter3/files/presentation/Ulf_Peschel.pdf

And here is Regensburger's Ph.D. dissertation detailing his experiments:

http://www.opus4.kobv.de/opus4-fau/oai/container/index/docId/3954
« Last Edit: 07/10/2015 02:18 PM by Rodal »

Offline SeeShells

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Last night I read:
Wimmer, M., Regensburger, A., Bersch, C., Miri, M., Batz, S., Onishchukov, G., & ... Peschel, U. (2013). Optical diametric drive acceleration through action-reaction symmetry breaking. Nature Physics, 9(12), 780-784. doi:10.1038/nphys2777

Two sentence summary: Photon-Photon interactions in clever devices are predicted and observed to break Newton's third law Symmetry.  I.e. S1 collides with S2 and both end up traveling in the same direction and velocity as S1's original vector.

If S2 is trapped bouncing off of the end plate of your resonator and a steady stream of input energy S1, then it isn't difficult to imagine this broken symmetry leading to a violation of Conservation of Momentum.

If your library has ebscohost you can get the paper free.  If you don't have access, PM me.

Are there other examples of broken symmetries?
Kind of...broken
A good paper with some interesting ideas and recommended.
Shell

Online WarpTech

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In a way, you are correct. In the Newtonian approximation the break even happens for k=1/c when 2/3 of the initial rest mass has been converted into kinetic energy. That is a significant speed where relativity is no longer negligible.
You must have been reading someone else's posts, because I never wrote any of that (and nor do I plan to)!  In my simple Newtonian analysis, the value of 'k' is not specified at all. I have no clue where you get this stuff!

You said,

...
1. Writing 'u' for the phase velocity, you get
k = u/c2 Newton/Watt = 1/c when u=c,
or in other words a pure photon rocket. But experimental evidence suggests a much higher value for k, and so if your formula is correct, it is predicting a superluminal phase velocity.
Is that your intent? Do you think that this observation is important?
...

I used 1/c as an example to solve for a particular case where break even was < c. But then I had an "AH HA Moment". LOL! Here is the Newtonian version too, in this case, the velocity goes to infinity rather than c, when 100% of the initial rest-energy has been spent. I hope you realize what this is saying. That for whatever energy is available in the battery to use for thrust, there will be a limiting velocity because the battery will go dead. It will not suddenly start to recharge when the speed exceeds some limit.
Todd
Dude. Your Newtonian expression for kinetic energy is not 0.5*m*v2, so how can I take this seriously?

It is exactly that. The mass at any time after you start the engine is (m - Ein/c^2). It is the mass you started with minus the mass you are using to accelerate. In your derivation, you hand wave this part by saying Ein, when in fact, there is no input to the system. Then you ignore where the energy is coming from by assuming that what comes out of the battery has negligible mass, then claim over unity by counting the energy gained from that expenditure as gravy.

Paradox resolved, case closed. My job is not to convince you, but to make sure others don't buy into more of this paradox fantasy.
Todd

Offline Rodal

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...]Dude. Your Newtonian expression for kinetic energy is not 0.5*m*v2, so how can I take this seriously?

...
 you ignore where the energy is coming from by assuming that what comes out of the battery has negligible mass, then claim over unity by counting the energy gained from that expenditure as gravy.

Paradox resolved, case closed. My job is not to convince you, but to make sure others don't buy into more of this paradox fantasy.
Todd

Thanks for taking your valuable time to carefully address this, Todd.
« Last Edit: 07/10/2015 02:11 PM by Rodal »

Offline TheTraveller

The extremely high Q claimed for the Chinese and other em-drive cavities is completely wrong.  I have already showed they are not calculating Q correctly.   The graph shown is not a photo taken from a network analyzer and so I believe it is just made up data.   These cavities are similar in most respects to cavity filters used for VHF and UHF repeaters.   A 145 MHz cavity typically has a Q = 350.   Scaling this up to 2.5 GHz and the Q may be as high as 1,000 - 2,000.  The skin effect and other factors increase the losses at higher frequencies.

So easy to claim the Chinese data has been made up, despite having no proof. Along with silly claims that would also say Eagleworks doesn't know how to measure Q either as per attached measured Q of 50,995.

I'll not bother to send you my data as you will claim it is also made up.
You guys are in my world when you talk Q, and yes, I've used $100K network analyzers and handhelds. Here's the deal...A Q of 10K is theoretically possible but highly unlikely. A 2.45 Ghz bandpass cavity would have to have a 3dB (half power BW) of 245 Khz...I've never seen such a beast. Here's the problem...center frequency drift of both the cavity and the source. You'd be chasing your tail trying to keep it centered.

I'm for projecting Qs of this design between 1 and 5K, meaning between about 2 & 5 Mhz 3dB BW. Even at this reduced Q, there will be drift concerns due to heating.

Bottom line, Qs are not 5 digits. On paper, yes...real world, no.

Maybe you need to actually measure a EMDrive cavity, as Eagleworks did as per attached.

With the low power from the NA, there will not be any significant heating of the cavity, so the resonant frequency will not be shifting around. You will need to sweep very slowly as it will take time for the cavity to fully fill with energy.
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.
Herman Melville, Moby Dick

Offline TheTraveller

Has anyone seen this paper yet. I am wondering if this is the paper @Traveller was talking about some pages back.

http://www.sciencedirect.com/science/article/pii/S0094576515002726

That is the one.

Which makes 6 peer reviewed EMDrive papers, published in 5 different journals / publications.
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.
Herman Melville, Moby Dick

Offline rfcavity

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The extremely high Q claimed for the Chinese and other em-drive cavities is completely wrong.  I have already showed they are not calculating Q correctly.   The graph shown is not a photo taken from a network analyzer and so I believe it is just made up data.   These cavities are similar in most respects to cavity filters used for VHF and UHF repeaters.   A 145 MHz cavity typically has a Q = 350.   Scaling this up to 2.5 GHz and the Q may be as high as 1,000 - 2,000.  The skin effect and other factors increase the losses at higher frequencies.

So easy to claim the Chinese data has been made up, despite having no proof. Along with silly claims that would also say Eagleworks doesn't know how to measure Q either as per attached measured Q of 50,995.

I'll not bother to send you my data as you will claim it is also made up.
You guys are in my world when you talk Q, and yes, I've used $100K network analyzers and handhelds. Here's the deal...A Q of 10K is theoretically possible but highly unlikely. A 2.45 Ghz bandpass cavity would have to have a 3dB (half power BW) of 245 Khz...I've never seen such a beast. Here's the problem...center frequency drift of both the cavity and the source. You'd be chasing your tail trying to keep it centered.

I'm for projecting Qs of this design between 1 and 5K, meaning between about 2 & 5 Mhz 3dB BW. Even at this reduced Q, there will be drift concerns due to heating.

Bottom line, Qs are not 5 digits. On paper, yes...real world, no.

Maybe you need to actually measure a EMDrive cavity, as Eagleworks did as per attached.

With the low power from the NA, there will not be any significant heating of the cavity, so the resonant frequency will not be shifting around. You will need to sweep very slowly as it will take time for the cavity to fully fill with energy.

The shape of the emdrive cavity, just due to its nature, will have a lower Q than a cylindrical cavity. Any EM professional (or even just grad student) has done material characterization in a cylindrical cavity of high Q in a strict measurement environment. This is because it's a required course at most places. Large Q is tricky to get, and can vary wildly with tiny temperature variations. The higher the q, the larger the variations. Why you find it prudent to argue against multiple experts with a Chinese journal paper (notoriously low quality) will forever be beyond me.

Offline birchoff

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Has anyone seen this paper yet. I am wondering if this is the paper @Traveller was talking about some pages back.

http://www.sciencedirect.com/science/article/pii/S0094576515002726

That is the one.

Which makes 6 peer reviewed EMDrive papers, published in 5 different journals / publications.

I believe there were a bunch of questions about if there was new experimental evidence included in the paper. Assuming my recollection of the questions that were being asked is correct. I feel safe in answering that from "MY PERSPECTIVE" it looks to be another design study. I do not see any new experimental data being discussed in the paper. Granted I have only skimmed through it since I just got it about 30 minutes ago.

Offline Flyby

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Judging by the tuning mechanisms used, looks like they used a rectangular waveguide.
In my opinion, I don't think they would go through the effort of drawing their picture to scale.



thank you very much for the details...
you are correct of course that the drawings are most likely not to scale, i'm aware of that, but considering it is all we have...as Dr. Rodal indicated, it's a guesstimate... while being well aware it might be faulty, i might give some insights we otherwise could overlook...

Now,  the cavity dimensions of the detail do not fit very well with the cut, but I'm taking the cavity inside as a guideline. You then get a 38.6%x87.5% (proportional dimension to the interior height of the frustum. (drawing will follow)

Secondly, the "microwave coupling window" (metal piece with rectangular opening) doesn't fit on the waveguide at all, it its current position, which lets me assume it should be rotate 90...
From that translated text, I could extract the dimensions from the best working opening (they tried 15 versions) 43.34mm x 31.78mm

I'll try to put that all into a top-cut drawing when i got some time...
« Last Edit: 07/10/2015 02:26 PM by Flyby »

Offline TheTraveller

The extremely high Q claimed for the Chinese and other em-drive cavities is completely wrong.  I have already showed they are not calculating Q correctly.   The graph shown is not a photo taken from a network analyzer and so I believe it is just made up data.   These cavities are similar in most respects to cavity filters used for VHF and UHF repeaters.   A 145 MHz cavity typically has a Q = 350.   Scaling this up to 2.5 GHz and the Q may be as high as 1,000 - 2,000.  The skin effect and other factors increase the losses at higher frequencies.

So easy to claim the Chinese data has been made up, despite having no proof. Along with silly claims that would also say Eagleworks doesn't know how to measure Q either as per attached measured Q of 50,995.

I'll not bother to send you my data as you will claim it is also made up.
You guys are in my world when you talk Q, and yes, I've used $100K network analyzers and handhelds. Here's the deal...A Q of 10K is theoretically possible but highly unlikely. A 2.45 Ghz bandpass cavity would have to have a 3dB (half power BW) of 245 Khz...I've never seen such a beast. Here's the problem...center frequency drift of both the cavity and the source. You'd be chasing your tail trying to keep it centered.

I'm for projecting Qs of this design between 1 and 5K, meaning between about 2 & 5 Mhz 3dB BW. Even at this reduced Q, there will be drift concerns due to heating.

Bottom line, Qs are not 5 digits. On paper, yes...real world, no.

Maybe you need to actually measure a EMDrive cavity, as Eagleworks did as per attached.

With the low power from the NA, there will not be any significant heating of the cavity, so the resonant frequency will not be shifting around. You will need to sweep very slowly as it will take time for the cavity to fully fill with energy.

The shape of the emdrive cavity, just due to its nature, will have a lower Q than a cylindrical cavity. Any EM professional (or even just grad student) has done material characterization in a cylindrical cavity of high Q in a strict measurement environment. This is because it's a required course at most places. Large Q is tricky to get, and can vary wildly with tiny temperature variations. The higher the q, the larger the variations. Why you find it prudent to argue against multiple experts with a Chinese journal paper (notoriously low quality) will forever be beyond me.

Why you ignore the Eagleworks measured Q, attached, is beyond me?

For my build, length changes need to exceed +-0.04m for any significant resonance to change and even then it is small.

Both Shawyer and the Chinese have recognised this effect and designed variable Rf generators that automatically adjust their frequency to track cavity resonant changes, as have I.

You see when you give an engineer a problem, he/she designs a way to cope with it and makes a more robust system.

BWT for the 5 Chinese peer reviewed papers, there are 4 different Journals/Publications involved.
« Last Edit: 07/10/2015 02:39 PM by TheTraveller »
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.
Herman Melville, Moby Dick

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