Author Topic: EM Drive Developments - related to space flight applications - Thread 3  (Read 1800571 times)

Offline Star One

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You were quite happy to lecture a poster on here about doing further research. So I'll turn that around and suggest if you want to know the people with alternatives to dark matter theory that you do some research on the matter.

It's not my job to justify your statements for you.

If you feel their is some exodus of scientists away from dark matter or dark energy, prove it.  I'm not going on some wild goose chase to learn about some fact I couldn't care less about.  As a "fringe" man yourself (and I don't mean that in a disparaging way, just that you are interested in alternative theories), you know how many people believe a theory has no impact on whether or not it's true.  I know this likewise, and so
Quote
There are an increasing number of scientists who are having doubts about the whole concept of Dark Matter/Energy.
is irrelevant. 

But I figured I'd ask to see if you could rustle up the source you got that from, or if you just made it up on the spot.

Such sources are easy to find should you have the mind to look.

Study finds possible alternative explanation for dark energy

Here's the article.

http://m.phys.org/news/2014-12-alternative-explanation-dark-energy.html

Here's the paper.

http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0115550

Here's one relating to Dark Matter.

Its crunch time for dark matter if WIMPs dont show

https://www.newscientist.com/article/mg22229712.600-its-crunch-time-for-dark-matter-if-wimps-dont-show

C'mon.  That wasn't an answer to my question and you know it.  I know alternative explanations are out there.  You can just read the wikipedia page for a brief introduction, simple as that.

You wrote:
Quote
There are an increasing number of scientists who are having doubts about the whole concept of Dark Matter/Energy.
Citing alternative theories doesn't justify that statement.  You need to show a source that demonstrates more and more scientists are abandoning dark matter and energy for alternative theories, not just that alternative theories exist, which is self evident.   

As your going to shift the goal posts on this and because I don't want to derail this thread any further that's all your going to get. We are clearly not going to agree on this so I'm not going to keep taking the thread off topic just to debate unrelated topics with you.
« Last Edit: 07/31/2015 07:37 PM by Star One »

Online Rodal

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Is there an exact solution for 915MHz though? Are you able to calculate dimensions for a copper frustrum?
yes

PS: when referring to "resonance (TM010)" I presume you are referring to the degenerate mode that roughly corresponds to TM010 in a cylinder, as strictly speaking there is no TM010 in a truncated cone since p=0 means constant field in the longitudinal direction and there is no mode in a truncated cone that has constant field in the longitudinal direction.
« Last Edit: 07/31/2015 07:41 PM by Rodal »

Offline zen-in

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I seem to be operating in Blurt Mode today. Here's another blurt:

If they can take an espresso machine to ISS, why not an EmDrive for microgee testing?

No doubt the expresso machine had to pass a complete battery of tests to certify it as spaceflight hardware.  An EM-Drive would fail the emi tests for starters.   Maybe a new improved expresso machine could be designed that used a magnetron to heat the beans and could double as a clandestine EM-Drive test. 

Offline X_RaY

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@zellerium: the "cardboard-like square part" is a thin piece made of mica which covers the end of the waveguide in a microwave oven. Mica (as well as white Teflon) is indeed transparent to microwaves. It lets the EM waves pass through it but protects the food from being impregnated by some undesirable substance that may be emitted from the magnetron cavity, like oil or metallic particles.

This is a thought to EmDrive DIYers: maybe it is a good idea to insert a Teflon or Mica sheet in the waveguide to protect the interior of the cavity from those substances, in the same manner as food is protected in the oven.

@Rodal, flux capacitor and all other experts:
I was thinking about the glimmer plate inside the microwave cooking oven and MW sputtering technique. Without such a plate how many metal ions would enter the cavity? Is it possible that the ions (with high velocity a.k. relativistic mass times rest mass) cause the trust while the EM-field inside the cavity give them preferred direction to a single(? or unsymmetrical ion impact) end plate?

@flux capacitor
Thanks for surprising to Tajmar. ;D
Here one can see how important the peer review process really is!

Is there really no one with ideas about (blue text) ? ???
« Last Edit: 07/31/2015 07:48 PM by X_RaY »

Offline SeeShells

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Dr. Rodal,

I'm reviewing all my collected data this morning sorting and categorizing. I can't locate the data sets for the cavity dimensions on the Rodal-complete ez data set we ran on June 23?

https://drive.google.com/folderview?id=0B1XizxEfB23tfjVmb1RiZXpaajd6WGpGQmpSWDkxRlV3cG10TEJmWVVEbTd2U0t4MC1aa1E&usp=sharing

Thanks,
Shell

Hi Shell,

there is no folder with that name in my Google Drive.  I cannot find what the root folder for that folder is from that link.  I would need to see what the root folders are to make sense of what this folder contains.

We need aero to interpret what this folder is.  I found a different folder titled Dr.Rodal.... etc. but contains different files.
Ok, we were just starting to get things organized about that time, no surprise. We'll wait to see if sero has some info.
Thanks,
Shell

Shell, I took a look inside these folders.  They are all images.  They are not csv files.  Hence this folder is nothing I ever analyzed.

From looking at the images, it looks like a very extended cone, extending it so that the small base is close to the apex and much smaller than usual.  I think that aero might have titled the folder "Rodal" not because he intended for me to analyze it (which I couldn't: there are no csv files) but because of my paper (attached below) on how cut-off doesn't apply to tapered cavities, (not my theory, something that is known by people involved in microwave cavities for dozens of years).

As I showed in my paper, the resonant frequency goes down as one extends the cone, so it should resonate at a lower frequency than 2.45 GHz in the same mode.
Sure it will resonate at some lower frequency because of the traveled distance. What is interesting is the modes it makes and watching the waves decay into Evanescent decay I'd assume. I was wondering if a CSV file was around for this.

Interesting chart observation on the TE013 mode.

Shell

Offline rfmwguy

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Hmmm, If Shawyer and Yang are using non standard methodology to figure out Q. What does this non standard methodology tell us. For example is there a difference in result between the Shawyer methodology and the standard methodology? If so, with what parameters does the Q result begin to diverge? What is the implication of this divergence?

Also, and most interestingly. Why has Shawyer and Yang opted for this non standard methodology?

Doing S11 return loss measurements to determine unloaded Q on a 1 port resonant system is NOT non standard. This method is the standard way to measure EMDrive cavities unloaded Q. As used by EWs, Shawyer, Prof Yang, Tajmar and myself.

What others are talking about is doing 2 port loaded Q measurements using S21 methodology. No one in the EMDrive world is interested in loaded Q values or doing 2 port (2 holes in the cavity) S21 measurements.

Here is a paper describing how to do unloaded Q measurements using S11. It is not correct to say using S11 to measure unloaded Q on a 1 port cavity is non standard.

2 documents attached to support that opinion.
You are not understanding me Mr T. The methodology EM Drive people are using is not the norm. Yet, they had placed sample ports in the device to make a standardized 2-port measurement. The fact they did not use the second port is indicative of a desire to uniquely define their Q...thousands of times the normal range of measurement.

There is no justification in EM drive Q measurements 3dB above best return loss. Again, any RF engineer will scoff at this "invented" measurement technique.

Since I am scoffing at this myself, I am committed to a 2 port Q measurement on my build as the RF industry would accept...those not using conventional methodogy are advertising their design weakness, IMO.

Online Rodal

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@zellerium: the "cardboard-like square part" is a thin piece made of mica which covers the end of the waveguide in a microwave oven. Mica (as well as white Teflon) is indeed transparent to microwaves. It lets the EM waves pass through it but protects the food from being impregnated by some undesirable substance that may be emitted from the magnetron cavity, like oil or metallic particles.

This is a thought to EmDrive DIYers: maybe it is a good idea to insert a Teflon or Mica sheet in the waveguide to protect the interior of the cavity from those substances, in the same manner as food is protected in the oven.

@Rodal, flux capacitor and all other experts:
I was thinking about the glimmer plate inside the microwave cooking oven and MW sputtering technique. Without such a plate how many metal ions would enter the cavity? Is it possible that the ions (with high velocity a.k. relativistic mass times rest mass) cause the trust while the EM-field inside the cavity give them preferred direction to a single end plate?

@flux capacitor
Thanks for surprising to Tajmar. ;D
Here one can see how important the peer review process really is!

Is there really no one with ideas about (blue text) ? ???

Yes, I had an idea, which was to "like" your post, which meant that I agree with you that this is another possible source of thrust.  :)
« Last Edit: 07/31/2015 07:49 PM by Rodal »

Online Rodal

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...
Sure it will resonate at some lower frequency because of the traveled distance. What is interesting is the modes it makes and watching the waves decay into Evanescent decay I'd assume. I was wondering if a CSV file was around for this.

Interesting chart observation on the TE013 mode.

Shell

1) No there are NO csv files to analyze for that case. I am 100% sure of that.  Aero would have to run it again, and would have to excite it at a lower frequency than 2.45 GHz to take into account the slightly lower natural frequency for the same mode.

2) Looking at my table, the frequency is lowered only a little with the extension towards the apex, for the same mode, and after a given amount it practically does not change much as one extends it.  This is due to the fact that in a tapered cavity the mode does not travel a longer distance once it reaches a transition zone: it stops travelling altogether in the section that is close to the small base, which becomes purely evanescent.

3) Note that in the aero runs he did NOT excite the mode that becomes purely evanescent near the small base.  Instead he excited a higher mode with higher p.  This was due to the fact that he did not lower the frequency perhaps or perhaps was due to antenna placement.

4) Now that I have found out that Yang in her 2010 paper in Chinese (not in the butchered translation) explicitly mentions the dielectric losses inside her cavity, this means to me that Yang may have used a dielectric for her experiments in 2010.  Why include an equation for dielectric losses lowering the Q if Yang did not use a dielectric inside her cavity?

http://forum.nasaspaceflight.com/index.php?topic=37642.msg1411922#msg1411922

A dielectric lowers the natural frequency.  Therefore the Yang/Shell geometry will be a WRONG model of Yang's geometry if Yang used a dielectric, because the Yang/Shell geometry was calculated on the basis that there was no dielectric inside her cavity.


5) Thus, more discussion is needed: did Yang use a dielectric for her experiments ?
« Last Edit: 07/31/2015 10:18 PM by Rodal »

Offline Flyby

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10^10 to 10^11 for superconducting single cell cavities

in the chart below Qo is the Intrinsic Q

http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=37642.0;attach=1051668;image
That was indeed why I was referring to 10^10 Q.. ;)

now, is there any way to translate the E and B field values into Watts?
or maybe do the inverse: determine the intensity of the E and B fields in a frustum (with a given watt).

The purpose would be to get an understanding how the energy intensity in the frustum compares to the Niobium resonators found at CERN... and eventually verify the apparent fantastic claims against some sense of realism...
I would like to understand what kinda power has been put in to achieve 86.5MV/m....

The referencing to those niobium resonators has been often made in the past months to validate the use of extreme high Q's in paper calculations, so it would be nice to really investigate if that really makes sense at all, from an engineering point of view.

Sadly, my calculus in physics is kinda... euh... lacking.. ???

I've been reading that niobium is used in particle accelerators because it loses its electrical resistance at -264C. I suppose that's ideal for creating massive E and B fields.

IIRC, that's still below liquid hydrogen (-252C), the cooling liquid Shawyer plans on using.
If he plans on using niobium EMdrives to achieve the extremely large forces, he should be using liquid helium instead (-269C), but then ofc, the concept or reusing  liquid hydrogen for generating electricity in his VTOL vehicles does not make that much sense anymore....
« Last Edit: 07/31/2015 08:09 PM by Flyby »

Offline X_RaY

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@zellerium: the "cardboard-like square part" is a thin piece made of mica which covers the end of the waveguide in a microwave oven. Mica (as well as white Teflon) is indeed transparent to microwaves. It lets the EM waves pass through it but protects the food from being impregnated by some undesirable substance that may be emitted from the magnetron cavity, like oil or metallic particles.

This is a thought to EmDrive DIYers: maybe it is a good idea to insert a Teflon or Mica sheet in the waveguide to protect the interior of the cavity from those substances, in the same manner as food is protected in the oven.

@Rodal, flux capacitor and all other experts:
I was thinking about the glimmer plate inside the microwave cooking oven and MW sputtering technique. Without such a plate how many metal ions would enter the cavity? Is it possible that the ions (with high velocity a.k. relativistic mass times rest mass) cause the trust while the EM-field inside the cavity give them preferred direction to a single end plate?

@flux capacitor
Thanks for surprising to Tajmar. ;D
Here one can see how important the peer review process really is!

Is there really no one with ideas about (blue text) ? ???

Yes, I had an idea, which was to "like" your post, which meant that I agree with you that this is another possible source of thrust.  :)
I know about your like :)
But the magnitude of this effect is not really clear for me at the moment, how many mass(particles/s will be emit) using a standard magnetron? That's what i ask for.

Maybe it's a little less or it's not? And with regard to thrust after 'Power off' in several experiments, i am not sure about the relevance.
« Last Edit: 07/31/2015 08:34 PM by X_RaY »

Offline WarpTech

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Hmmm, If Shawyer and Yang are using non standard methodology to figure out Q. What does this non standard methodology tell us. For example is there a difference in result between the Shawyer methodology and the standard methodology? If so, with what parameters does the Q result begin to diverge? What is the implication of this divergence?

Also, and most interestingly. Why has Shawyer and Yang opted for this non standard methodology?

Doing S11 return loss measurements to determine unloaded Q on a 1 port resonant system is NOT non standard. This method is the standard way to measure EMDrive cavities unloaded Q. As used by EWs, Shawyer, Prof Yang, Tajmar and myself.

What others are talking about is doing 2 port loaded Q measurements using S21 methodology. No one in the EMDrive world is interested in loaded Q values or doing 2 port (2 holes in the cavity) S21 measurements.

Here is a paper describing how to do unloaded Q measurements using S11. It is not correct to say using S11 to measure unloaded Q on a 1 port cavity is non standard.

2 documents attached to support that opinion.

Hmmm.. this is an interesting paper. The power delivered to the load, PL implies that in a tapered waveguide where w0 is a variable. More power is being delivered to the end of the frustum where w ~ w0, and less power will be delivered to the end where these frequencies have a larger difference. So if the frequency is tuned to match the small end, then more power will be delivered to this end, and less will be delivered to the big end. The difference must either be stored energy, thrust or lost as heat.
Todd

Online Rodal

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Shawyer has updated his device Force generation and direction summary to include the Tajmar results as attached.

That makes 8 devices, tested in 4 countries and 5 labs.

Another error that Shawyer has in that chart (besides the direction of the force in NASA's experiments) is the specific force for Yang's experiments.  Shawyer has only 0.288 N/kW for Yang.  Yang reported 1 N/kW.  You now say that it was really 4 N/kW. Regardless, why is Shawyer reporting only 0.288 N/kW which makes it look like Yang's experiments have lower specific force than Shawyer's Flight Thruster ?  (it looks like the peer reviewers for Shawyer's paper missed all of this ...)

« Last Edit: 07/31/2015 10:21 PM by Rodal »

Offline flux_capacitor

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Another error that Shawyer has in that chart (besides the direction of the force in NASA's experiments) is the specific force for Yang's experiments.  Shawyer has only 0.288 N/kW for Yang.  Yang reported 1 N/kW.  You now say that it was really 4 N/kW. Regardless, why is Shawyer reporting only 0.288 N/kW and making Yang's experiments to have lower specific force than Shawyer's Flight Thruster ?  (it looks like the peer reviewers for Shawyer's paper missed all of this ...)

Explanation:

Specific thrust to power ratio is given for a specific thrust measured at a specific input power, which does not vary linearly a priori (but this last statement is not true, as explained below).

288 N/kW is Yang's specific thrust measured for the maximum force recorded (720 mN) at the maximum power she used (2.5 kW).

1 N/kW is a contrario the maximum mean specific thrust Yang recorded at an input power of 300 W, where she measured a thrust of 310 then 270 mN (2013 Yang paper, page 7 and 8).

But after she corrected the dip in the thrust versus power curve due to the magnetron to cavity bandwidth mismatch (see same paper, page 8) we can indeed calculate an average specific thrust comprised between 2 and 4 N/kW (and even an -erroneous?- 14N/kW for the first recorded value):



As Yang concludes, this relation shows that the EM thrust monotonously increases with the practical power augmentation.

EDIT: This was already pointed out by TheTraveller several days ago.
« Last Edit: 07/31/2015 10:55 PM by flux_capacitor »

Online Rodal

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Another error that Shawyer has in that chart (besides the direction of the force in NASA's experiments) is the specific force for Yang's experiments.  Shawyer has only 0.288 N/kW for Yang.  Yang reported 1 N/kW.  You now say that it was really 4 N/kW. Regardless, why is Shawyer reporting only 0.288 N/kW and making Yang's experiments to have lower specific force than Shawyer's Flight Thruster ?  (it looks like the peer reviewers for Shawyer's paper missed all of this ...)

Explanation:

Specific thrust to power ratio is given for a specific thrust measured at a specific input power, which does not vary linearly a priori (but this last statement is not true, as explained below).

288 N/kW is Yang's specific thrust measured for the maximum force recorded (720 mN) at the maximum power she used (2.5 kW).

1 N/kW is a contrario the maximum mean specific thrust Yang recorded at an input power of 300 W, where she measured a thrust of 310 then 270 mN (2013 Yang paper, page 7 and 8).

But after she corrected the dip in the thrust versus power curve due to the magnetron to cavity bandwidth mismatch (see same paper, page 8) we can indeed calculate an average specific thrust comprised between 2 and 4 N/kW (and even an -erroneous?- 14N/kW for the first recorded value):



As Yang concludes, this relation shows that the EM thrust monotonously increases with the practical power augmentation.

EDIT: This was already pointed out by TheTraveller several days ago.

Yes, but apples should be compared to apples.  Why does Shawyer use in the chart a figure for Yang at a much higher thrust than the one achieved by the Flight Thruster.  It doesn't make sense.  What would make sense is to compare the specific forces for the same thrust, or to compare the highest specific force, or some other fair comparison, but not to make the present arbitrary comparison.  Shawyer should report something like "Mean Specific Thrust" or "Highest Specific Thrust" etc.

The present comparison is making the Shawyer Flight Thruster look better than Yang's which is not accurate as Yang reported the highest thrust, and the highest specific thrust than any other EM Drive, including the Flight Thruster.
« Last Edit: 07/31/2015 11:43 PM by Rodal »

Offline deltaMass

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As a practical matter, the figure of interest is N/W where the power is the input power. If you have a fancy-schmancy (sorry, intelligently engineered) way of getting a high percentage of that thrudge to actually enter the cavity and bounce around in there, more power to you. But it's the raw input power that counts.

It also allows me to go on and on and on about conservation  8)

Offline deltaMass

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Shawyer has updated his device Force generation and direction summary to include the Tajmar results as attached.

That makes 8 devices, tested in 4 countries and 5 labs.

Another error that Shawyer has in that chart (besides the direction of the force in NASA's experiments) is the specific force for Yang's experiments.  Shawyer has only 0.288 N/kW for Yang.  Yang reported 1 N/kW.  You now say that it was really 4 N/kW. Regardless, why is Shawyer reporting only 0.288 N/kW which makes it look like Yang's experiments have lower specific force than Shawyer's Flight Thruster ?  (it looks like the peer reviewers for Shawyer's paper missed all of this ...)
I thought it had already been established that his paper was not truly peer-reviewed.  If you are allowed to present at the conference, then you are allowed to publish. The commentator (qraal or similar?) mentioned the parlous state of the papers in general.

Offline rfmwguy

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Offline deltaMass

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now, is there any way to translate the E and B field values into Watts?
or maybe do the inverse: determine the intensity of the E and B fields in a frustum (with a given watt).
The only way I know is to take the well-known formula for the energy density of the field, which is based on the square of the RMS field values, multiply that by the cavity volume, and multiply once again by the frequency. However, this doesn't seem to mean much physically, since the energy density is a continuously changing function of both time and space within the cavity. I have no idea in that case how the volume term would be handled. It sounds like you're back to a "sim" to chop it all up into cells and then add everything up at the end.

Online Bob Woods

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A note to you ALL: Thank you, thank you VERY much.

As I boy I dreamed of physics and spaceflight and read all I could. I went to college with dreams of a life in physics, but changed course as the Vietnam War moved my focus to politics and government, which is where I spent my career.

I never lost my love of science, followed it all my life, and found this site/forum in the spring when a friend referred me.

I can't follow the math, but the concepts you folks are formulating, debating, pontificating and wandering in are actually pretty clear. To me, following these threads brings an excitement that I yearned for as a boy, but did not attain.

Right or wrong, your discussions and jousting show the ability of human kind. The development and application of the scientific method is clearly, to me, the finest singular achievement of the human race; the fundamental tenet that makes ongoing discovery possible.

Keep it up. There IS new physics out there. You folks discover it every few years, and watching this online collaboration is opening up new avenues of thought and insight in real time.

I am sure you'll figure out whether the EM drive is real or not. If not, move on to the next possibility. I'm getting old and I'd still like see Einstein an Hawking proved wrong about FTL travel.

Offline deltaMass

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A comment on simulations from elsewhere.

Tagline: BEWARE!

    E/M simulators are notorious for generating funny results. The usual culprits:

    Meshing issues.
    Quantization errors.

Indeed. I said it before, but it might bear repeating: I got a gain on Steorn's configuration using Comsol, of the same magnitude that they claimed, with the mesh to the max that the PC could handle. However, rotating the entire config by 5 degrees (whatever) and re-running gave a loss. As the laws of physics are rotationally symmetric, this showed that the result couldn't be trusted.
« Last Edit: 07/31/2015 11:56 PM by deltaMass »

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