### Author Topic: EM Drive Developments - related to space flight applications - Thread 3  (Read 2277525 times)

#### MyronQG

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##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #3880 on: 07/10/2015 02:35 PM »
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

It seems something is wrong with your derivation of the relativistic breakeven velocity equation. In the limiting case Ein=0 (no on board source of propulsive energy) the solution turns out to be imaginary!

Besides, your Newtonian approximation lacks the rest mass equivalent energy in the Eout calculation; you only took into account the total battery energy.
« Last Edit: 07/10/2015 02:41 PM by MyronQG »

#### SeeShells

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##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #3881 on: 07/10/2015 02:40 PM »
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.
Wonderful! Real world vs paper ideas. On paper and software >meeps the Q of my build is quite high but in the real world I'll be happy with anything under 10k. Just too many variables that effect it and a increased input bandwidth from the magnetron might not be a bad thing as the tuned system fluctuates due to every major component in the system.

You all have a good day, I'm off to get more pieces and parts.

Shell

#### Rodal

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##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #3882 on: 07/10/2015 02:45 PM »
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.

But to make rfcavity's point, if we are going to quote NASA, these are the reported Q's for NASA's experiments:

NASA Brady, White, March, Lawrence, and Davies, a 7320
NASA Brady, White, March, Lawrence, and Davies, b 18100
NASA Brady, White, March, Lawrence, and Davies, c 22000
NASA March et.al. Partial vacuum   6726

Minimum Q = 6726 (vacuum experiment)
Maximum Q = 22 000 (experiment with TE012 that they were NOT able to replicate)

Mean Q = 13500

Most of the latest experiments reported by NASA were in vacuum, with Q's of about 7,000

All these experimental reports make the point that the Q=50,000 in the image you quote is not representative of the actual Q's of the EM Drive during NASA's EM Drive experiments.
« Last Edit: 07/10/2015 02:52 PM by Rodal »

#### TheTraveller

##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #3883 on: 07/10/2015 02:54 PM »
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.

But to make rfcavity's point, if we are going to quote NASA, these are the published Q's for their experiments:

NASA Brady, White, March, Lawrence, and Davies, a 7320
NASA Brady, White, March, Lawrence, and Davies, b 18100
NASA Brady, White, March, Lawrence, and Davies, c 22000
NASA March et.al. Partial vacuum   6726

Minimum Q = 6726 (vacuum experiment)
Maximum Q = 22 000 (experiment with TE012 that they were NOT able to replicate)

Mean Q = 13500

Please stop with the one sided half truths. You know very well those cavities had a big dielectric inside then and dielectrics inside the cavity increase losses and reduce Q, yet you failed to mention that very important fact.

I will attach again the Eagleworks measured Q of their copper cavity WITHOUT A DIELECTRIC. As I assume you can read, if you ignore it again, well that is your loss.

You need to understand I have every image and document Paul March attached to his many years of NSF posts.
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 3
« Reply #3884 on: 07/10/2015 02:58 PM »
...
Please stop with the one sided half truths. You know very well those cavities had a big dielectric inside then and dielectrics inside the cavity increase losses and reduce Q, yet you failed to mention that very important fact.

I will attach again the Eagleworks measured Q of their copper cavity WITHOUT A DIELECTRIC. As I assume you can read, if you ignore it again, well that is your loss.

You need to understand I have every image and document Paul March attached to his many years of NSF posts.
My post listed correct facts: I listed all of NASA's experimental reports for Q where they reported thrust from an EM Drive.

I even took the time to list the authors, the reported Q, and to calculate the Min, Max, and Mean of the measurements.

You instead are reporting the Q of an EM Drive sitting on a surface, not involved in any experimental thrust measurement ! , made by @Star-Drive at the NSF forum with the explicit quote that he didn't know what mode shape it was being excited or whether it would result in any thrust measurement.  Then you follow that with an unfair accusation.

My point was, and continues to be, that NASA has not reported any thrust measurement with an EM Drive where the Q was higher than 22000, and the latest reports in a vacuum have  a Q of only about 7,000.
« Last Edit: 07/10/2015 03:12 PM by Rodal »

#### sghill

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##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #3885 on: 07/10/2015 02:59 PM »
Keep it civil please gents.  This 3rd thread has over half a million views on it.  Perhaps it's time for a fourth.
« Last Edit: 07/10/2015 02:59 PM by sghill »
Bring the thunder Elon!

#### rfmwguy

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##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #3886 on: 07/10/2015 03:09 PM »
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.

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.
I have to say Mr. T. if there was anything that singlehandedly caused me to doubt EW's testing, it was their staggering claims of 50K Q and 1.1 VSWR. I've refrained from beeing too disbelieving, but the topic has come up too many times. I was not there and don't feel the right to hammer them, just want to make the point that in 30+ years of working with similar stuff (all symetrical cans and boxes designed for max Q) I have never seen anything like it. Consider this a rare hand-wave.

#### TheTraveller

##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #3887 on: 07/10/2015 03:12 PM »
...
Please stop with the one sided half truths. You know very well those cavities had a big dielectric inside then and dielectrics inside the cavity increase losses and reduce Q, yet you failed to mention that very important fact.

I will attach again the Eagleworks measured Q of their copper cavity WITHOUT A DIELECTRIC. As I assume you can read, if you ignore it again, well that is your loss.

You need to understand I have every image and document Paul March attached to his many years of NSF posts.
My post was correct: I listed all of NASA's experimental reports for Q where they reported thrust from an EM Drive.

I even took the time to list the authors, the reported Q, and to calculate the Min, Max, and Mean of the measurements.

You instead are reporting the Q of an EM Drive sitting on a surface, not involved in any experimental thrust measurement ! , and with an accusation.

You listed a selected subset of the available data. Plus now and then you failed to mention an important fact:

All those measured cavity Qs you listed had an internal dielectric that increases losses and reduced the Q.

So you can't compare those dielectric cavity Qs to a cavity that has no dielectric.

This is the data you selected to not mention:

Shawyer's 1st Experimental EMDrive used a dielectric, reported Q 5,900.
Shawyer's 2nd Demonstrator EMDrive did not use a dielectric, reported Q 45,000.
Shawyer's 3rd Flight Thruster EMDrive did not use a dielectric, reported Q 50,000.
« Last Edit: 07/10/2015 03:13 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 3
« Reply #3888 on: 07/10/2015 03:19 PM »
..

You listed a selected subset of the available data. Plus now and then you failed to mention an important fact:

All those measured cavity Qs you listed had an internal dielectric that increases losses and reduced the Q.

So you can't compare those dielectric cavity Qs to a cavity that has no dielectric.

This is the data you selected to not mention:

Shawyer's 1st Experimental EMDrive used a dielectric, reported Q 5,900.
Shawyer's 2nd Demonstrator EMDrive did not use a dielectric, reported Q 45,000.
Shawyer's 3rd Flight Thruster EMDrive did not use a dielectric, reported Q 50,000.
Of course not.

This is what I posted:

<<But to make rfcavity's point, if we are going to quote NASA, these are the reported Q's for NASA's experiments>>

It explicitly refers to NASA's experiments, the point being to bring in the reported Q's for experiments involved in thrust measurements, so as to not to miss-characterized them based  on the measurement of an EM Drive sitting on a surface that was never tested for thrust, and where the author warns that he doesn't know the mode shape and warns that he doesn't now whether it could result in a thrust measurement.

Of course I didn't list Shawyer's Q, neither Yang's or Prof. Tajmar's. No post is meant to be a complete compilation of all the data that has ever been reported by everybody in the world.

I understand that Prof. Tajmar is going to be reporting extremely low Q's

You should not be unfairly accusing people. We are having a conversation to find out what's going on.  If you have other data to bring up to the conversation, great, please do it in a positive manner, without accusing others.
« Last Edit: 07/12/2015 03:10 PM by Rodal »

#### rfcavity

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##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #3889 on: 07/10/2015 03:20 PM »
...
Please stop with the one sided half truths. You know very well those cavities had a big dielectric inside then and dielectrics inside the cavity increase losses and reduce Q, yet you failed to mention that very important fact.

I will attach again the Eagleworks measured Q of their copper cavity WITHOUT A DIELECTRIC. As I assume you can read, if you ignore it again, well that is your loss.

You need to understand I have every image and document Paul March attached to his many years of NSF posts.
My post was correct: I listed all of NASA's experimental reports for Q where they reported thrust from an EM Drive.

I even took the time to list the authors, the reported Q, and to calculate the Min, Max, and Mean of the measurements.

You instead are reporting the Q of an EM Drive sitting on a surface, not involved in any experimental thrust measurement ! , and with an accusation.

You listed a selected subset of the available data. Plus now and then you failed to mention an important fact:

All those measured cavity Qs you listed had an internal dielectric that increases losses and reduced the Q.

So you can't compare those dielectric cavity Qs to a cavity that has no dielectric.

This is the data you selected to not mention:

Shawyer's 1st Experimental EMDrive used a dielectric, reported Q 5,900.
Shawyer's 2nd Demonstrator EMDrive did not use a dielectric, reported Q 45,000.
Shawyer's 3rd Flight Thruster EMDrive did not use a dielectric, reported Q 50,000.

Can you demonstrate the calculation method of these q and the calibration method to move the analyzers reference plane to the cavity?

#### wallofwolfstreet

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##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #3890 on: 07/10/2015 03:22 PM »
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

No, the paradox is not at all "resolved".  I honestly did my best to just stay out of this whole conversation, but there is no other way around it.  I read through all your posts, none of them offer any resolution to this issue.  I pray people reading this aren't taken in.  I feel like I'm taking crazy pills.

First of all, energy conservation when the drive is on a ship that is accelerating is a red herring.  It's been stated and shown so many times that I'm not going to bother to link it, but a COE paradox exists if the drive is just attached to a wheel and spun at a great enough velocity.  No tangential acceleration.  The energy source need not be attached to the wheel itself, so your expression for Eout doesn't hold.  Even if what you posted previously worked, which it doesn't, you wouldn't have resolved the COE issue.

Come back to the Newtonian version you posted here.  This time, instead of assuming COE by equating Ein and Eout, let Ein=Pin*t.  Now let k=F/Pin and solve for v.  You can do this the hard way with integral of F/m(t), where m(t)=mo-Pin*t/c2 or do it the easy way by realizing you underestimate v (and consequently Eout) if you just set m(t)=mo (v=(Pin*k*t)/mo).  Thus this simplification sets a lower Eout then in actuality,

Go through that procedure as I just did with a k greater than 1/c.  See if Ein<Eout for some v<c.

Quote
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.

Out of all the things involving the EMdrive, the COE paradox is one of the least fantasy of them all.

#### TheTraveller

##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #3891 on: 07/10/2015 03:27 PM »
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.

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.
I have to say Mr. T. if there was anything that singlehandedly caused me to doubt EW's testing, it was their staggering claims of 50K Q and 1.1 VSWR. I've refrained from beeing too disbelieving, but the topic has come up too many times. I was not there and don't feel the right to hammer them, just want to make the point that in 30+ years of working with similar stuff (all symetrical cans and boxes designed for max Q) I have never seen anything like it. Consider this a rare hand-wave.

Have you ever tested a cylindrical tapered cavity resonator?

You see here is what I read:

1) Shawyer reports non dielectric cavity Qs of 45,000 and 50,000.

2) The Chinese report non dielectric cavity Qs of 117,500 in a very unusual cavity design that minick's spherical end plates using flat end plates.

3) Eagleworks reports a non dielectric cavity Q of 50,955.

Just maybe there is something going on here that is outside your experience base?
It Is Time For The EmDrive To Come Out Of The Shadows

#### TheTraveller

##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #3892 on: 07/10/2015 03:34 PM »
...
Please stop with the one sided half truths. You know very well those cavities had a big dielectric inside then and dielectrics inside the cavity increase losses and reduce Q, yet you failed to mention that very important fact.

I will attach again the Eagleworks measured Q of their copper cavity WITHOUT A DIELECTRIC. As I assume you can read, if you ignore it again, well that is your loss.

You need to understand I have every image and document Paul March attached to his many years of NSF posts.
My post was correct: I listed all of NASA's experimental reports for Q where they reported thrust from an EM Drive.

I even took the time to list the authors, the reported Q, and to calculate the Min, Max, and Mean of the measurements.

You instead are reporting the Q of an EM Drive sitting on a surface, not involved in any experimental thrust measurement ! , and with an accusation.

You listed a selected subset of the available data. Plus now and then you failed to mention an important fact:

All those measured cavity Qs you listed had an internal dielectric that increases losses and reduced the Q.

So you can't compare those dielectric cavity Qs to a cavity that has no dielectric.

This is the data you selected to not mention:

Shawyer's 1st Experimental EMDrive used a dielectric, reported Q 5,900.
Shawyer's 2nd Demonstrator EMDrive did not use a dielectric, reported Q 45,000.
Shawyer's 3rd Flight Thruster EMDrive did not use a dielectric, reported Q 50,000.

Can you demonstrate the calculation method of these q and the calibration method to move the analyzers reference plane to the cavity?

What nonsense.

The data I have is what you have. Anything not published that Roger Shawyer has shared with me was posted on NSF.

Shawyer has been working with microwave systems most of his professional life. I'm sure he knows how to measure Q.

Both the results of the Experimental EMDrive and of the Demonstrator EMDrive were checked by a group of UK aerospace experts, under control of the UK Dept of Defense.
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 3
« Reply #3893 on: 07/10/2015 03:40 PM »
Please let's don't answer others by replying that what they are asking or writing is nonsense, referring to them as "Dude", making toes curl, writing about crazy pills, or accusing them.  It stops the conversation.  Let's have a conversation by using facts and analysis and let's avoid writing about any negative personal feelings.

« Last Edit: 07/10/2015 03:47 PM by Rodal »

#### Rodal

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##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #3894 on: 07/10/2015 04:02 PM »
QUESTIONS:

1) Is there an IEEE or other organization's standard for how to properly measure and report loaded Q's ?

2)  Is there an IEEE or other organization's standard for how to establish the zero dB reference plane for an S11 plot, for how to measure the S11 VNA return loss? (*)

_________________________________
(*) Apparently, the Agilent VNA manual all it says on this S11 topic is that first perform an open & short calibration of the VNA, then use resulting zero dB reference plane as your S11 zero energy standard.
« Last Edit: 07/10/2015 04:07 PM by Rodal »

#### Notsosureofit

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##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #3895 on: 07/10/2015 04:07 PM »
For what it's worth we always used the phase shift rather than loss measurements (old time stuff)

#### rfmwguy

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##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #3896 on: 07/10/2015 04:22 PM »
For those serious students of filters, there is only one reference:

http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=6323867

The Handbook of Filter Systhesis written in 1967 stands unchallenged as THE definitive reference; highpass, bandpass, lowpass and bandstop (notch). Chebychev, Gaussian, Bessel, Linear Phase, Elliptical functions; its all there. If Zverev were alive today, he would no doubt vigorously challenge 5 digit Qs, as I think we all should in non-optical systems.

I cannot refute any claim, as I did not witness the test procedure...its simply a red flag based on my personal experience.

#### mittelhauser

##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #3897 on: 07/10/2015 04:24 PM »
Both the results of the Experimental EMDrive and of the Demonstrator EMDrive were checked by a group of UK aerospace experts, under control of the UK Dept of Defense.

I'm a very interested lurker who I believe represents a large number of folks who follow along with these debates and form our own opinions on who is credible and who is not.

Traveller, you often throw out this tidbit as proof.  However, I have not seen or found reference to this beyond your repeated statement.  I agree that such a validation would be very valuable.

My (very specific) question for you is...

How do I verify that statement ("Both the results of the Experimental EMDrive and of the Demonstrator EMDrive were checked by a group of UK aerospace experts, under control of the UK Dept of Defense.") as being accurate?

Can you point me to a report produced by those experts which validated the data?

Having read every post for the last 6 months, I don't believe that I have seen that.  I'd love to see something written by somebody besides you which actually validated the data.  It would be a major credibility boost.

Thanks,

-Jon

#### hhexo

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##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #3898 on: 07/10/2015 04:31 PM »
...
Initially, when power on energy front just left the antenna and is coasting to destination, we see thrust. The energy front doesn't even know yet that the other end of the cavity is closed, if it were open this initial thrust would be gained "for good". But since it is closed, it is absorbed and opposite thrust compensate the initial kick. We have reached live steady state, a constant flow of energy from places A (battery) to places B (cavity walls, some patches more, some less). During this phase, the process is not thrusting, but it is coasting, at (very small) constant velocity that was given by the (very short lived) initial transient kick. We would like to continue on this acquired velocity at no ongoing energetic flow (constant power) cost, but switching off the process we will see the energy tail leave the antenna a little bit before it reaches the walls : during this transient the kick is opposite to the initial one, and we are back at the same inertial rest frame as initially (albeit a little bit translated). Overall, on the on/off cycle we have gained a delta X but not a delta V.
...

@frobnicat's excellent analysis of the initial (and final) transient of the on/off cycle got me thinking...

It's true that the on/off transitory is too quick (a microsecond or so, somebody calculated) and doesn't affect the experiments much.
However, it occurs to me that it should be possible, by modulating Pin with a Low Frequency Oscillation (i.e. very low compared to the resonant frequency, fLFO << fresonance), to induce a corresponding LFO in the frustum's position.

The amplitude modulation of the power constitutes a "signal" carried over the "carrier" which is the EM wave at the resonance frequency (hah! My little knowledge of signal theory is finally useful! Well, sort of...).
This signal propagates at the group velocity vg, so if the resonant signal "bounces" a lot of times there is a very small but significant delay between the power issued at the RF feed and the power eventually dissipated at some point in the frustum.

If the RF feed is positioned so that the radiation emitted by the RF feed hits one plate with less delay than the other, there will be a difference in the power hitting each plate, but not in the power emitted in any direction at the RF feed. So the instantaneous momentum transfer from the RF feed to the body of the device is zero, but the instantaneous momentum transfer to the device from the power modulation hitting the plates is non-zero.
Of course, it all integrates to zero on an integer number of LFO periods. I'm not claiming average thrust, only oscillation.

Basically, if the power is modulated, the "delayed" version on one plate is always at a phase offset compared to the "delayed" version on the other plate. The "bouncing" only exasperates this effect as the phase offset situation repeats at every "bounce" and at each plate we have a composition of a large number of phase-shifted copies of the modulation. If the power modulation is a sinusoid, the sum of these phase-delayed sinusoids produces, again, a sinusoid (as it is well known).
And so the difference of the power hitting each plate is again a sinusoid at fLFO.

The net effect is that there will be a swing towards one side, and then a swing towards the other side, following the LFO modulation of Pin, and the total net effect averaged over an integer number of periods will still be zero. Nil.

However, fLFO can be made arbitrarily low. The lower it is, the longer the oscillation will be, although at the same time the entity of the oscillation force reduces. Still, the oscillation force is amplified by the "bouncing" (i.e. by the Q?) because of the constructive composition of all the phase-shifted sinusoids and might end up being measurable.

Why is this important?
If our experiments only bother to measure thrust for a few seconds (e.g. Iulian's), and the power supply to the RF feed has some LFO we don't know about, with a frequency low enough, we could erroneously believe to have measured genuine thrust when we have measured only a portion of a transient oscillation.

Any EmDrive experiment should run for a long time, or alternatively carefully check Pin for LFOs.

Don't just "wub" the frustum!

#### rfmwguy

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##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #3899 on: 07/10/2015 04:47 PM »
...
Initially, when power on energy front just left the antenna and is coasting to destination, we see thrust. The energy front doesn't even know yet that the other end of the cavity is closed, if it were open this initial thrust would be gained "for good". But since it is closed, it is absorbed and opposite thrust compensate the initial kick. We have reached live steady state, a constant flow of energy from places A (battery) to places B (cavity walls, some patches more, some less). During this phase, the process is not thrusting, but it is coasting, at (very small) constant velocity that was given by the (very short lived) initial transient kick. We would like to continue on this acquired velocity at no ongoing energetic flow (constant power) cost, but switching off the process we will see the energy tail leave the antenna a little bit before it reaches the walls : during this transient the kick is opposite to the initial one, and we are back at the same inertial rest frame as initially (albeit a little bit translated). Overall, on the on/off cycle we have gained a delta X but not a delta V.
...

@frobnicat's excellent analysis of the initial (and final) transient of the on/off cycle got me thinking...

It's true that the on/off transitory is too quick (a microsecond or so, somebody calculated) and doesn't affect the experiments much.
However, it occurs to me that it should be possible, by modulating Pin with a Low Frequency Oscillation (i.e. very low compared to the resonant frequency, fLFO << fresonance), to induce a corresponding LFO in the frustum's position.

The amplitude modulation of the power constitutes a "signal" carried over the "carrier" which is the EM wave at the resonance frequency (hah! My little knowledge of signal theory is finally useful! Well, sort of...).
This signal propagates at the group velocity vg, so if the resonant signal "bounces" a lot of times there is a very small but significant delay between the power issued at the RF feed and the power eventually dissipated at some point in the frustum.

If the RF feed is positioned so that the radiation emitted by the RF feed hits one plate with less delay than the other, there will be a difference in the power hitting each plate, but not in the power emitted in any direction at the RF feed. So the instantaneous momentum transfer from the RF feed to the body of the device is zero, but the instantaneous momentum transfer to the device from the power modulation hitting the plates is non-zero.
Of course, it all integrates to zero on an integer number of LFO periods. I'm not claiming average thrust, only oscillation.

Basically, if the power is modulated, the "delayed" version on one plate is always at a phase offset compared to the "delayed" version on the other plate. The "bouncing" only exasperates this effect as the phase offset situation repeats at every "bounce" and at each plate we have a composition of a large number of phase-shifted copies of the modulation. If the power modulation is a sinusoid, the sum of these phase-delayed sinusoids produces, again, a sinusoid (as it is well known).
And so the difference of the power hitting each plate is again a sinusoid at fLFO.

The net effect is that there will be a swing towards one side, and then a swing towards the other side, following the LFO modulation of Pin, and the total net effect averaged over an integer number of periods will still be zero. Nil.

However, fLFO can be made arbitrarily low. The lower it is, the longer the oscillation will be, although at the same time the entity of the oscillation force reduces. Still, the oscillation force is amplified by the "bouncing" (i.e. by the Q?) because of the constructive composition of all the phase-shifted sinusoids and might end up being measurable.

Why is this important?
If our experiments only bother to measure thrust for a few seconds (e.g. Iulian's), and the power supply to the RF feed has some LFO we don't know about, with a frequency low enough, we could erroneously believe to have measured genuine thrust when we have measured only a portion of a transient oscillation.

Any EmDrive experiment should run for a long time, or alternatively carefully check Pin for LFOs.

Don't just "wub" the frustum!
Waskly Wabbit, you...very obvious you're thinking. I've skirted this also, but not as thoroughly. If this were true, why the different end plate diameters? These bad boys should also show force, but to my knowledge never have: http://www.eham.net/data/classifieds/images/332154.jpg

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