Author Topic: EM Drive Developments - related to space flight applications - Thread 3  (Read 1841966 times)

Offline SeeShells

  • Senior Member
  • *****
  • Posts: 2335
  • Every action there's a reaction we try to grasp.
  • United States
  • Liked: 2982
  • Likes Given: 2601
For conservation of E & M folks, Dark Matter disappearing from theory is like saying Newton was a fraud, imo.
The balancing force to gravity is labeled dark matter to explain the imbalance of forces.

I'm not sure how that follows.  Maybe you meant dark energy there, because it is "repulsive" while familiar mass-energy is attractive?  Dark matter behaves just like regular matter gravitationally.   

What imbalance of forces are you referring to specifically here?  There is no imbalance of forces in gravity from a Newton's 3rd law perspective.
Sloppily saying gravity is the only know force without a repulsive condition, thus an imbalance in the big scheme of things.

Haven't you heard of Exotic Matter? It represents repulsive gravity and causes inflation. The ZPF is the driving force, setting the scale of protons and sub-atomic particles which are in equilibrium with it. Where the ZPF power is decreasing, we have gravity and gravitational length contraction and time dilation as matter deflates. Where the ZPF is increasing (think, going up-hill) the opposite is true. The ZPF is gaining power and matter is inflated in the process of lifting it. (The opposite of length contraction and time dilation.)

Exotic Matter, is simply normal matter immersed in a more powerful ZPF. The ZPF increases the energy stored but it also inflates the volume of that matter, such that the equilibrium energy density is lower than it would be in a less powerful ZPF, or in a gravity well. It is the ZPF that is responsible for gravity, it doesn't gravitate, it inflates.
Todd
Yep, exotic/dark matter and other theories. When it is eventually proven, so leads the way to GUT...at least thats my guess.
Taking a break from sorting and filing and getting all the data ducks in a row.

It does my heart good we know what 5% of the universe is made of and how it works, oops we don't quite yet. :D We seem to have a long way to go yet.

Offline deltaMass

  • Full Member
  • ****
  • Posts: 955
  • A Brit in California
  • Liked: 671
  • Likes Given: 275
I'll just say this straight out: Yang's 1 to 4 Newtons of force couldn't be thermal, surely? She is reporting forces so strong you would feel it push on your hand. So...is there any corroboration for this claim? Has anyone actually been to her lab and witnessed this first hand?

Offline flux_capacitor

  • Full Member
  • ****
  • Posts: 562
  • France
  • Liked: 679
  • Likes Given: 925
Besides, as mentioned multiple times by WarpTech and TheTraveller, the waveguide canNOT attach to the cavity with the 68.6 mm height !

Wish that when the wrong dimensions were pointed out to Tajmar he would have asked people at this lab to do a thorough job at double checking ALL numbers and not just the radii ...

Sigh ...

I'm sorry for not being able to keep up with the incredible speed of the thread during the past few days.

Martin Tajmar just confirmed the internal end plates of his EmDrive are curved (spherical ends) and not flat! He can't confirm the real height because the guy who made the real cavity measurements is currently in holiday so we'd have to wait for the return from the summer holidays to ask this very important question on the real length.

Quote from: Martin Tajmar
It was the internal height – but our two surfaces were curved (like in Shawyer’s patent). We also modified it a bit during the tuning process – do the real actual height may be a bit different. My student went on holiday and I’m also on holiday starting next week.

I answered the cavity provided cannot neither physically hold the large WR340 waveguide (there isn't the minimum space for it) nor achieve any resonance and told him I will come back later after the summer for that important question to ask to his student.

Offline deltaMass

  • Full Member
  • ****
  • Posts: 955
  • A Brit in California
  • Liked: 671
  • Likes Given: 275
For some reason I find this funny...

Offline Rodal

  • Senior Member
  • *****
  • Posts: 5894
  • USA
  • Liked: 6040
  • Likes Given: 5315
Besides, as mentioned multiple times by WarpTech and TheTraveller, the waveguide canNOT attach to the cavity with the 68.6 mm height !

Wish that when the wrong dimensions were pointed out to Tajmar he would have asked people at this lab to do a thorough job at double checking ALL numbers and not just the radii ...

Sigh ...

I'm sorry for not being able to keep up with the incredible speed of the thread during the past few days.

Martin Tajmar just confirmed the internal end plates of his EmDrive are curved (spherical ends) and not flat! He can't confirm the real height because the guy who made the real cavity measurements is currently in holiday so we'd have to wait for the return from the summer holidays to ask this very important question on the real length.

Quote from: Martin Tajmar
It was the internal height – but our two surfaces were curved (like in Shawyer’s patent). We also modified it a bit during the tuning process – do the real actual height may be a bit different. My student went on holiday and I’m also on holiday starting next week.

I answered the cavity provided cannot neither physically hold the large WR340 waveguide (there isn't the minimum space for it) nor achieve any resonance and told him I will come back later after the summer for that important question to ask to his student.

I can model the spherical ends exactly and spherical ends don't justify that small height to resonate at 2.45GHz

All of this gives me the impression:

1) Tajmar is managing lofts of research projects.  Not hands-on involved in the details of the EM Drive project.  He has to wait for somebody to come back from holiday to simply answer what the height of the EM Drive is? How about going to the lab with a ruler ? The Professor at MIT that chaired my Ph.D. thesis had a whole lab with many students and post-Docs, experimental labs, and courses to teach.  He would have gone and double checked the dimensions himself. We are talking about a factor of almost 2 here.  Sigh

2) His remarks about buying the microwave oven and the cooking oil were in jest.  I doubt he had the time to do that personally.  Maybe the guy that is on vacation was the one that bought the cooking oil.

3) Tajmar not involved in numerical modeling or mathematical modeling of cavities.   He doesn't quite know what the frequency should be with different heights or ends.  What student run the COMSOL FEA model? how about asking him/her?
« Last Edit: 07/31/2015 04:59 PM by Rodal »

Offline deltaMass

  • Full Member
  • ****
  • Posts: 955
  • A Brit in California
  • Liked: 671
  • Likes Given: 275
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?

Offline TheTraveller

@TT:
There's a video of Shawyer's device slowly rotating (you've posted it many times; you know the one). There's also a graph of power and thrust over time (you've also posted many times).
Are you sure that they go together?

Reason I ask is that the speed looks about constant - there is little discernable acceleration at all.

Use the YouTube video. Run it at 1/4 speed. Record the video seconds between the pointer hitting each mark. Can use freeze frame to do this.

You can also import the video from www.emdrive.com and use a video software package to determine the time between the pointer hitting each mark.

I measured the time between each of the 15 marks and the middle 0.5 estimated marks on the table and got the attached velocity curve. This is not the entire acceleration period, just the pointer moving right over the 15 marks on the table.
« Last Edit: 07/31/2015 04:39 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

Offline deltaMass

  • Full Member
  • ****
  • Posts: 955
  • A Brit in California
  • Liked: 671
  • Likes Given: 275
Thank you! That is great info.

Hang on - is that a plot of position or of velocity (vertical y axis)?
Time on the x axis, right?
« Last Edit: 07/31/2015 04:45 PM by deltaMass »

Offline LasJayhawk

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?

Don't think NASA would go for it. But a moonshine still and a microwave might fly. :)

I'm thinking about having a copper frustrum made up, and as it turns out, moonshiners are quite good at making them at a reasonable price.

http://www.coppermoonshinestills.com/index.html

Offline SeeShells

  • Senior Member
  • *****
  • Posts: 2335
  • Every action there's a reaction we try to grasp.
  • United States
  • Liked: 2982
  • Likes Given: 2601
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

Offline X_RaY

  • Full Member
  • ****
  • Posts: 777
  • Germany
  • Liked: 999
  • Likes Given: 2186
@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!
« Last Edit: 07/31/2015 05:04 PM by X_RaY »

Offline TheTraveller

Think of it as horsepower in the cavity world. The bigger the better, right? Over the top pronouncements get attention. When anyone claims super high Qs, its all relative to they test methodology they are using in the real world.

I thought we had settled how Q was measured.

To be very clear, the Chinese, EW, Shawyer and myself are taking unloaded 1 port S11 -3db off the peak return loss dB bandwidths. That is the way the Q is measured for these cavities. It may not be how you would measure the loaded Q but it is the way Q is measured in EMDrives. Shawyers Force equation uses S11 1 port return loss dB driven unloaded Q.

Attached is an example of a 1 port S11 return loss Q measurement Paul March posted on NSF. The cavity did not have a dielectric. Clearly Qs of 50k are possible with a plain hand made copper frustum with flat end plates. Curve the end plates and the Q will go higher. Machine the cavity to 0.05mm accuracy and the Q will go higher. Highly polish all the interior surfaces and the Q will go higher.
"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

It is deceptive to use the efficiency parameter (N/kW) when you see on Yang's graph's that when you increase power you end up with a way lower efficiency (720mN/2.5kW).

What this shows that the thermal impact has a far bigger impact then you assume and that with and increased Q you're massing up gigantic power intensities in the resonance patterns.

With needed Q's in the order of 10^10 i really doubt if cooled nitrogen will be able to keep the frustum walls cooled...
IIRC, Shawyer talked about 17MW of stored energy in the cavity, by only using "700W to 1kW-ish" microwave generators and with a Q of barely 50k....

Agreed, i'm no specialist in the matter, but it looks to me a near impossible engineering challenge, to pack all that in a minimal configuration, with a low enough weight to power ratio, so it can fly...

IF the EMdrive ever turns out to be something (no hard evidence till today), it will be usable for orbit positioning, interplanetary travel and maybe interstellar probes...but terrestrial liftoff vehicles ? nah...

The thermal degeneration on the Q is only going to grow the more power you put into it...at certain point, even supercooled liquids wont be enough to handle the thermal issues....

Just adding on to this, does anyone have any idea (@rfmqguy in particular) what the highest Q ever obtained by an electromagnetic resonator (whether a cavity or circuit) is?  Ie. in the actual physical world, what is the best Q ever obtained?
Good question wolfy, air cavities can exceed 10,000 with silver and gold plating and tight tolerances. But this is measuring Q in the classic center resonance/3dB bandwidth and NOT return loss; i.e. forward power. IOW a 2 port measurement.

These frustums are being tested with a single port, like an antenna, and they are calculating 3dB below either zero insertion, relative 3dB (to insertion loss) or in the case of China, 3dB above center return loss notch (that of course gives ridiculous Q).

So, guess I'll stick with around 10K in a classic 2 port configuration. All else is a foreign language to my way of testing.

In the EmDrive world, cavity Q is measured as unloaded, being 1 port S11 -3db off the max return loss dB. Shawyers Force equation also uses unloaded Q.

I didn't make the rules. EMDrive unloaded Q is measured as described above. Doing it any other way will not tie in with how Shawyer, EW, the Chinese and others measure Q.
"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

Electropolishing required to eliminate multipaction:

Electropolishing is GOOD. Have real world experience with the process.

I plan to have one of my frustums silver electropolished then gold flashed to stop the silver tarnishing. Might now have one copper electropolished as well to compare against highly polished copper.
"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

I asked Martin Tajmar directly by email about cavity dimensions that would be off by a factor 2, and he replied confirming the numbers were indeed internal radii instead of diameters.

He added he already uploaded a revised manuscript altogether with some other typo corrections and some additional clarifications at the AIAA website, but revisions from the conference will appear only after 21st of August.

For now, the updated paper is online on the UD-Dresden website.

In the updated paper the height is still confirmed to be 68.6 mm:
Quote from: Martin Tajmar
Our final tapered cavity design had an internal top radius of 38.5 mm, a bottom radius of 54.1 mm and a height of 68.6 mm

So:
- internal big diameter = 0.1082 m
- internal small diameter = 0.077 m
- height = 0.00686 m

To @Rodal, @TheTraveller and others: can you try to find resonances and modes with your COMSOL and spreadsheets programs with those dimensions?

No resonance found using those revised numbers.
"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

@TT:
There's a video of Shawyer's device slowly rotating (you've posted it many times; you know the one). There's also a graph of power and thrust over time (you've also posted many times).
Are you sure that they go together?

Reason I ask is that the speed looks about constant - there is little discernable acceleration at all.

You need to stop frame and measure the time between the marks. Here is the 1st part of the acceleration as the pointer passed over the 15 marks to the right.
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.”
Herman Melville, Moby Dick

Offline X_RaY

  • Full Member
  • ****
  • Posts: 777
  • Germany
  • Liked: 999
  • Likes Given: 2186
Think of it as horsepower in the cavity world. The bigger the better, right? Over the top pronouncements get attention. When anyone claims super high Qs, its all relative to they test methodology they are using in the real world.

I thought we had settled how Q was measured.

To be very clear, the Chinese, EW, Shawyer and myself are taking unloaded 1 port S11 -3db off the peak return loss dB bandwidths. That is the way the Q is measured for these cavities. It may not be how you would measure the loaded Q but it is the way Q is measured in EMDrives. Shawyers Force equation uses S11 1 port return loss dB driven unloaded Q.

Attached is an example of a 1 port S11 return loss Q measurement Paul March posted on NSF. The cavity did not have a dielectric. Clearly Qs of 50k are possible with a plain hand made copper frustum with flat end plates. Curve the end plates and the Q will go higher. Machine the cavity to 0.05mm accuracy and the Q will go higher. Highly polish all the interior surfaces and the Q will go higher.
"Unloaded" is relative, the port (for S11) measurement have already a 50 Ohm impedance, its design to be almost free of reflections... ???
But i don't know if there's a better way to discover the Q, actually no i think

german file with explanations how to do
http://www-elsa.physik.uni-bonn.de/Lehrveranstaltungen/FP-E106/E106-Erlaeuterungen.pdf

Offline Rodal

  • Senior Member
  • *****
  • Posts: 5894
  • USA
  • Liked: 6040
  • Likes Given: 5315
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.
« Last Edit: 07/31/2015 05:23 PM by Rodal »

Offline X_RaY

  • Full Member
  • ****
  • Posts: 777
  • Germany
  • Liked: 999
  • Likes Given: 2186
I asked Martin Tajmar directly by email about cavity dimensions that would be off by a factor 2, and he replied confirming the numbers were indeed internal radii instead of diameters.

He added he already uploaded a revised manuscript altogether with some other typo corrections and some additional clarifications at the AIAA website, but revisions from the conference will appear only after 21st of August.

For now, the updated paper is online on the UD-Dresden website.

In the updated paper the height is still confirmed to be 68.6 mm:
Quote from: Martin Tajmar
Our final tapered cavity design had an internal top radius of 38.5 mm, a bottom radius of 54.1 mm and a height of 68.6 mm

So:
- internal big diameter = 0.1082 m
- internal small diameter = 0.077 m
- height = 0.00686 m

To @Rodal, @TheTraveller and others: can you try to find resonances and modes with your COMSOL and spreadsheets programs with those dimensions?

No resonance found using those revised numbers.
http://forum.nasaspaceflight.com/index.php?topic=37642.msg1410218#msg1410218 ;)

Offline TheTraveller

So TT is deluding himself when he quotes 6-figure Q values from Yang because they are unrealistic (and wrong).

I know what I'm doing and I'm not deluding myself. 100K unloaded S11 1 port return loss measured Q is obtainable. This is now Q is measured in the EMDrive world. Shawyers Force equation uses unloaded Q so it has to be measured as 1 port S11 -3dB off the peak return loss dB value.

S21 2 port loaded Q is not measured as EMDrive cavities are not 2 port devices. EM energy is not stored and then moved on in a EMDrive cavity. There is 1 port and that is how the energy gets inside. So yes the EMDrive cavity is like an antenna except it doesn't emit EM wave radiation. Likewise it is like a 2 port cavity as EM wave energy is inputted, except it doesn't have a 2nd output port and the output is Force.
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.”
Herman Melville, Moby Dick

Tags: