Author Topic: EM Drive Developments - related to space flight applications - Thread 11  (Read 223720 times)

Offline Star One

  • Senior Member
  • *****
  • Posts: 9982
  • UK
  • Liked: 1961
  • Likes Given: 192
It annoys me about the Tajmar paper that even though on here his setup has received criticism and the sceptics elsewhere have criticised his setup as well its still been widely reported.
« Last Edit: 06/16/2018 02:09 pm by Star One »

Offline Augmentor

  • Member
  • Posts: 87
  • Liked: 50
  • Likes Given: 64
This technical paper is what you want to make of it.

PT Barnum is claimed to have said, "I don't care what the newspapers say about me as long as they spell my name right." but that does not apply to this paper.

As for the quality of the report, there are conflicts. One is that brand new, state of the ar equipment was being used. Another issue is the magnetic shielding. Stray magnetic fields can create issues and false positives as well as false negatives. 

Dr. Tajmar et al  have done their best so far to reduce the number of artifacts and identify thrust signatures. In this particular case, two papers should have been done since there are three tests going on: emDrive, Mach Effect MEGA, and that of experimental setup with new test equipment.

The show is not over yet. The media loves controversy and their acceptance of negative preliminary results is good in that larger thrusts will now be a "surprise" and therefore, worthy news of reporting widely. Time will tell.

Work on the theory, experiments, modeling and simulations will continue in the drilling down to the essence of thrust using particles and waves as well as EM and gravitational forces.



Offline Star One

  • Senior Member
  • *****
  • Posts: 9982
  • UK
  • Liked: 1961
  • Likes Given: 192
The reason I mention it again is I have been catching up on my back issues of New Scientist magazine and a fairly small report, though prominently placed on page seven, headlined ’Impossible’ space drive doesn’t work can be found in issue number 3179 for those interested.

Offline Peter Lauwer

  • Full Member
  • **
  • Posts: 287
  • Setting up an exp with torsion balance
  • Netherlands
  • Liked: 339
  • Likes Given: 460
The reason I mention it again is I have been catching up on my back issues of New Scientist magazine and a fairly small report, though prominently placed on page seven, headlined ’Impossible’ space drive doesn’t work can be found in issue number 3179 for those interested.

Yes, the sceptics often need even less thoroughness of the scientific reports in order to see their premises confirmed than the "wishful thinkers" do.  ::)
Science is a way of trying not to fool yourself. The first principle is that you must not fool yourself, and you are the easiest person to fool.   — Richard Feynman

Offline RotoSequence

  • Full Member
  • ****
  • Posts: 1152
  • Liked: 835
  • Likes Given: 900
Is that because you believe we cannot generate high enough energies on the Earth for the foreseeable future? That the more interesting physics exists in the extremely high energy realms?

The experimental data supports that we cannot generate interesting physics results at terrestrial energy levels, while cosmology shows that existing knowledge falls short of fully explaining the universe. I'm not confident that ever higher energies would help explain the missing links either, but I don't believe that particle accelerators like the LHC are the future of discovery in physics.

Offline meberbs

  • Full Member
  • ****
  • Posts: 1896
  • Liked: 1789
  • Likes Given: 418
It annoys me about the Tajmar paper that even though on here his setup has received criticism and the sceptics elsewhere have criticised his setup as well its still been widely reported.
And it annoys me when people claim that the paper has been criticized despite the fact that no valid criticisms have been provided. (The only provided criticisms have been saying that they should do the things that the paper explicitly states they plan to do as part of future work.)

If you want to criticize the way the media is reporting on the paper, that is fine, but old news since the media exaggerates every scientific report they can (which annoys me too). Making false claims about criticisms of the paper is just as bad as any misrepresentations the media makes though.

The reason I mention it again is I have been catching up on my back issues of New Scientist magazine and a fairly small report, though prominently placed on page seven, headlined ’Impossible’ space drive doesn’t work can be found in issue number 3179 for those interested.

Yes, the sceptics often need even less thoroughness of the scientific reports in order to see their premises confirmed than the "wishful thinkers" do.  ::)
There is a reason for this, and it is rooted in actual scientific data:
https://xkcd.com/1132/

Offline Star One

  • Senior Member
  • *****
  • Posts: 9982
  • UK
  • Liked: 1961
  • Likes Given: 192
It annoys me about the Tajmar paper that even though on here his setup has received criticism and the sceptics elsewhere have criticised his setup as well its still been widely reported.
And it annoys me when people claim that the paper has been criticized despite the fact that no valid criticisms have been provided. (The only provided criticisms have been saying that they should do the things that the paper explicitly states they plan to do as part of future work.)

If you want to criticize the way the media is reporting on the paper, that is fine, but old news since the media exaggerates every scientific report they can (which annoys me too). Making false claims about criticisms of the paper is just as bad as any misrepresentations the media makes though.

The reason I mention it again is I have been catching up on my back issues of New Scientist magazine and a fairly small report, though prominently placed on page seven, headlined ’Impossible’ space drive doesn’t work can be found in issue number 3179 for those interested.

Yes, the sceptics often need even less thoroughness of the scientific reports in order to see their premises confirmed than the "wishful thinkers" do.  ::)
There is a reason for this, and it is rooted in actual scientific data:
https://xkcd.com/1132/

You say that yet this very thread criticism of his setup is clearly given.

https://forum.nasaspaceflight.com/index.php?topic=42978.msg1823724#msg1823724

Offline meberbs

  • Full Member
  • ****
  • Posts: 1896
  • Liked: 1789
  • Likes Given: 418
You say that yet this very thread criticism of his setup is clearly given.

https://forum.nasaspaceflight.com/index.php?topic=42978.msg1823724#msg1823724
I clearly stated that the only things provided have just been repeating the "future work" information in the paper, which is not criticism, just an indication that the person saying those things did not read the paper. More power, and better magnetic shielding are both explicitly stated in the paper. The linked post is a perfect example of how claiming there are "criticisms" of the paper is at least as disingenuous as any misreporting that has happened in the media.

Offline Monomorphic

  • Full Member
  • ****
  • Posts: 1429
  • United States
    • /r/QThruster
  • Liked: 3927
  • Likes Given: 1272
I clearly stated that the only things provided have just been repeating the "future work" information in the paper, which is not criticism, just an indication that the person saying those things did not read the paper.

I read the paper and watched Tajmar's presentation, thank you very much.  >:( 

The criticisms noted are valid even though Tajmar plans on ruling most of them out in future experiments. Some of the items pointed out, such as why they claim to be exciting mode TM212 during their presentation, when that mode is 500Mhz away in simulations, and why they are 15Mhz away from any known mode for those dimensions, AND the fact that they chose not to share their smith chart plot, are serious problems that need to be addressed specifically in the next paper. 

We also pointed out that the wiring was sophomoric at best as the twisted pairs were not twisted very well, the main power leads were over a meter long, and the ground loops have not been identified. We also pointed out that the amplifier and most other electrical components rotate with the copper frustum, instead of only the frustum rotating. It is not clear if Tajmar plans on addressing these issues in the future.

Once Tajmar confirms the resonant mode with IR camera, or other means, then that will alleviate most of my concerns.  I am glad this is planned and look forward to the results.  I know that is one of the last hurdles I am working on before I throw in the towel...


Offline Star One

  • Senior Member
  • *****
  • Posts: 9982
  • UK
  • Liked: 1961
  • Likes Given: 192
I clearly stated that the only things provided have just been repeating the "future work" information in the paper, which is not criticism, just an indication that the person saying those things did not read the paper.

I read the paper and watched Tajmar's presentation, thank you very much.  >:( 

The criticisms noted are valid even though Tajmar plans on ruling most of them out in future experiments. Some of the items pointed out, such as why they claim to be exciting mode TM212 during their presentation, when that mode is 500Mhz away in simulations, and why they are 15Mhz away from any known mode for those dimensions, AND the fact that they chose not to share their smith chart plot, are serious problems that need to be addressed specifically in the next paper. 

We also pointed out that the wiring was sophomoric at best as the twisted pairs were not twisted very well, the main power leads were over a meter long, and the ground loops have not been identified. We also pointed out that the amplifier and most other electrical components rotate with the copper frustum, instead of only the frustum rotating. It is not clear if Tajmar plans on addressing these issues in the future.

Once Tajmar confirms the resonant mode with IR camera, or other means, then that will alleviate most of my concerns.  I am glad this is planned and look forward to the results.  I know that is one of the last hurdles I am working on before I throw in the towel...

Thank you for this update. I put a lot of weight on what you have to say about these things in this thread.

Offline flux_capacitor

  • Full Member
  • ****
  • Posts: 662
  • France
  • Liked: 796
  • Likes Given: 1059
The reason I mention it again is I have been catching up on my back issues of New Scientist magazine and a fairly small report, though prominently placed on page seven, headlined ’Impossible’ space drive doesn’t work can be found in issue number 3179 for those interested.

Here is the news in brief of the print version attached, as an excerpt so small in the whole journal does not contravene the Right to Quote of the Berne convention. The online and longer version is here:
• New Scientist: ‘Impossible’ EM drive doesn’t seem to work after all

The vast majority of the media is aligning with this pessimistic "case closed" headline:

• Ars Technica: NASA’s EM-drive is a magnetic WTF-thruster
• BGR: NASA’s ‘impossible’ fuel-free engine actually is impossible after all
• Dailymail: Blow for NASA's 'impossible' EM Drive as study finds thrust seen in previous tests were caused by Earth's magnetic fields
• Engadget: 'Impossible' EM drive may actually be impossible after all
• Forbes: The EmDrive, NASA's 'Impossible' Space Engine, Really Is Impossible
• Interesting Engineering: NASA's "Impossible" EmDrive Space Thruster Could Be Impossible After All
• Space.com: 'Impossible' EmDrive Space Thruster May Really Be Impossible
• Science Alert: The Latest Test on The 'Impossible' EM Drive Concludes It Doesn't Work
• The Register: EmDrive? More like BS drive: Physics-defying space engine flunks out

What is criticized here is these media have put the final nail in the EmDrive coffin whereas Tajmar just presented a work in progress report at a conference, investigating spurious effects and listing what to do in future experiments to characterize and reduce these sources of error.

However some rare medias have written neutral titles more in line with reality and the long-lost journalists' code of deontology:

• Popular Mechanics: New Study Casts Doubt on the "Impossible" EmDrive (But this weird propulsion idea isn't dead yet)
• National Geographic: NASA's 'Impossible' Space Engine Tested—Here Are the Results
• Motherboard: A German Team Is Now Trying to Make the ‘Impossible’ EmDrive Engine

But they are all pessimistic in the end, since absolutely no journalist criticized the experiment like Monomorphic did (about the effective resonance and EM mode, the possibility of a phantom rtn loss dip, the use of a right-angle RF connector, loosely twisted pairs, very long mean power leads, wires jointly rotating with the cavity, no side wall coupler, etc.) simply because none of these journalists have the minimum expertise to do so, and they didn't bother to ask experts. I even suspect, due to the very similarity in their headlines, that they almost all embroidered the same short story from some news agency like Reuters or AP.

Offline Star One

  • Senior Member
  • *****
  • Posts: 9982
  • UK
  • Liked: 1961
  • Likes Given: 192
I’ve noticed something before now where an article with identical if not very similar wording appears in multiple publications online.

Offline PotomacNeuron

  • Full Member
  • **
  • Posts: 262
  • Do I look like a neuroscientist?
  • MD
  • Liked: 166
  • Likes Given: 42
I clearly stated that the only things provided have just been repeating the "future work" information in the paper, which is not criticism, just an indication that the person saying those things did not read the paper.

I read the paper and watched Tajmar's presentation, thank you very much.  >:( 

The criticisms noted are valid even though Tajmar plans on ruling most of them out in future experiments. Some of the items pointed out, such as why they claim to be exciting mode TM212 during their presentation, when that mode is 500Mhz away in simulations, and why they are 15Mhz away from any known mode for those dimensions, AND the fact that they chose not to share their smith chart plot, are serious problems that need to be addressed specifically in the next paper. 

We also pointed out that the wiring was sophomoric at best as the twisted pairs were not twisted very well, the main power leads were over a meter long, and the ground loops have not been identified. We also pointed out that the amplifier and most other electrical components rotate with the copper frustum, instead of only the frustum rotating. It is not clear if Tajmar plans on addressing these issues in the future.

Once Tajmar confirms the resonant mode with IR camera, or other means, then that will alleviate most of my concerns.  I am glad this is planned and look forward to the results.  I know that is one of the last hurdles I am working on before I throw in the towel...

Also they should rotate their test bed as a whole to assess the influence of the Earth magnetic field. Shielding is much harder and costly. We can't tell definitely how good the shielding is. They could probably give up shielding and use rotation test instead. They may additionally try Helmholtz coils.
I am working on the ultimate mission human beings are made for.

Offline meberbs

  • Full Member
  • ****
  • Posts: 1896
  • Liked: 1789
  • Likes Given: 418
I clearly stated that the only things provided have just been repeating the "future work" information in the paper, which is not criticism, just an indication that the person saying those things did not read the paper.

I read the paper and watched Tajmar's presentation, thank you very much.  >:( 

The criticisms noted are valid even though Tajmar plans on ruling most of them out in future experiments.
No, when you make criticisms that someone has already stated they are working on, especially when you don't acknowledge they are working on them, you are not criticizing them. With acknowledgement, you are just summarizing their paper, without acknowledgement you are slandering them by implicit claims that they don't know they should work on basic things.

Some of the items pointed out, such as why they claim to be exciting mode TM212 during their presentation, when that mode is 500Mhz away in simulations, and why they are 15Mhz away from any known mode for those dimensions, AND the fact that they chose not to share their smith chart plot, are serious problems that need to be addressed specifically in the next paper. 
Strange, none of those things were pointed out in the referenced post. If you read the paper carefully, they claim to be using the resonance at 1865 MHz, while they show TM212 at 1971MHz by simulation. They don't claim to be exciting TM212 in the paper, though they should have explicitly stated which mode they are exciting. While more data is always good, I am not aware of any specific information from a Smith chart that is required for a good emDrive experiment.

We also pointed out that the wiring was sophomoric at best
Sophomoric is a word used to insult a person, and does not detail an issue with wiring.

We also pointed out that the amplifier and most other electrical components rotate with the copper frustum, instead of only the frustum rotating.
The attenuator test he ran isolates issues due to wiring, it is not obvious that a "flip without moving wiring" test like he did for the Mach drive would be necessary.

Overall, you are not providing helpful criticism, and instead you are misrepresenting the paper, and even using personal insults.

Offline Monomorphic

  • Full Member
  • ****
  • Posts: 1429
  • United States
    • /r/QThruster
  • Liked: 3927
  • Likes Given: 1272
Strange, none of those things were pointed out in the referenced post. If you read the paper carefully, they claim to be using the resonance at 1865 MHz, while they show TM212 at 1971MHz by simulation. They don't claim to be exciting TM212 in the paper, though they should have explicitly stated which mode they are exciting. While more data is always good, I am not aware of any specific information from a Smith chart that is required for a good emDrive experiment.

I'm sorry you missed it, but this and more was posted in follow-up posts by me and others such as this one:  https://forum.nasaspaceflight.com/index.php?topic=42978.msg1825716#msg1825716

They did make the claim in their presentation that they thought they were exciting mode TM212 (at time 48:20). This was in response to a question from Dr. Rodal. But TM212 is 570Mhz away according to COMSOL and FEKO. Perhaps they meant TE212, but that is 15Mhz away from where they are seeing the RL. The student clearly said he thinks it is TM212, but that he is not sure. Another thing to note is the mode Tajmar claims is TM212 at 1971 Mhz (1.971 Ghz) was identified as Tx3xx by NASA using COMSOL. If they are not sure, or are confused on this, then they need to get it straight soon.

The smith chart plot is necessary to 1. make sure there is a circular plot, which indicates resonance, and 2. to make sure there are no modes too close, as there appears to be with Tajmar's RL plot. Every serious experiment I know of has provided a smith chart plot.

Then you lament about personal insults directly after insulting our intelligence by claiming we didn't read the paper.  ::)   
« Last Edit: 06/17/2018 03:46 pm by Monomorphic »

Offline meberbs

  • Full Member
  • ****
  • Posts: 1896
  • Liked: 1789
  • Likes Given: 418
Strange, none of those things were pointed out in the referenced post. If you read the paper carefully, they claim to be using the resonance at 1865 MHz, while they show TM212 at 1971MHz by simulation. They don't claim to be exciting TM212 in the paper, though they should have explicitly stated which mode they are exciting. While more data is always good, I am not aware of any specific information from a Smith chart that is required for a good emDrive experiment.

I'm sorry you missed it, but this and more was posted in follow-up posts by me and others such as this one:  https://forum.nasaspaceflight.com/index.php?topic=42978.msg1825716#msg1825716
I read those posts, but did not go into detail, since that is not what Star One referenced as examples of "criticism."

They did make the claim in their presentation that they thought they were exciting mode TM212 (at time 48:20). This was in response to a question from Dr. Rodal. But TM212 is 570Mhz away according to COMSOL and FEKO. Perhaps they meant TE212, but that is 15Mhz away from where they are seeing the RL. The student clearly said he thinks it is TM212, but that he is not sure.
So your actual criticism is that someone misspoke about a detail they didn't specifically remember during an oral presentation?

Another thing to note is the mode Tajmar claims is TM212 at 1971 Mhz (1.971 Ghz) was identified as Tx3xx by NASA using COMSOL. If they are not sure, or are confused on this, then they need to get it straight soon.
Well, their simulation results in the paper clearly show a mode that is not a Tx3xx. Someone is wrong here, or some information has been miscommunicated so that apples and oranges are being compared, while assuming they are both apples. As I said, more information from them would be good to clarify this, but they have a cavity and took data from it. They were tracking resonance, which clearly existed in the VNA plot.

The smith chart plot is necessary to 1. make sure there is a circular plot, which indicates resonance, and 2. to make sure there are no modes too close, as there appears to be with Tajmar's RL plot. Every serious experiment I know of has provided a smith chart plot.
Resonance and nearby modes can be seen in the RL plot, which you even just pointed out. Every experiment has had a return loss plot, not all have shown the Smith chart as well to my knowledge. The paper is preliminary results mostly focused on their generic test setup capabilities and methodologies, showing how it can be generic and used for multiple types of devices. The details of either device tested are secondary to the main point in the paper, describing progress on their general test setup, which people on both ends of reactions to this seem to be struggling to understand.

Then you lament about personal insults directly after insulting our intelligence by claiming we didn't read the paper.  ::)
Saying that your statements indicate that you didn't read the paper is not an insult to your intelligence. It is a statement that what you said either contradicts the paper (in the case of modes) or presents information in the paper as if it is new information you came up with and they didn't think of. I only am pointing out these are statements that someone who carefully read the paper shouldn't be making. The possibilities from there are either that you didn't read the paper or you did. If you didn't, that explains your statements, if you did, then your statements start to sound malicious. I assumed the first because I don't like assuming malice. None of the options say anything about your intelligence. Comparing any of that to the literal direct insult you used is ... I'm not sure how to describe that.

Offline D_Dom

  • Global Moderator
  • Full Member
  • *****
  • Posts: 497
  • Liked: 198
  • Likes Given: 112
 Quoting the first posting upthread "subjective wordy statements are discouraged." Focus on technical aspects of the topic at hand.  Praise in public, critique in private is tricky here because it is an open forum.
 Again quoting Chris "Be excellent to each other". We all benefit from the open exchange of ideas, many thanks to everyone who posts. Lets keep the sigal to noise ratio high.
Space is not merely a matter of life or death, it is considerably more important than that!

Offline Monomorphic

  • Full Member
  • ****
  • Posts: 1429
  • United States
    • /r/QThruster
  • Liked: 3927
  • Likes Given: 1272
Here is the first attempt at confirming mode shape using a probe inside the cavity. Of course, it sounds a lot easier than it actually is.  Not only is it hard to know if i'm aligned with the side-wall, small movements with my hand have a huge effect. A probe mount that can slide in and out in a controlled fashion would be very helpful. 

Drilling the holes seemed to have had a very large effect on Q as the RL dip wasn't nearly as narrow after each hole.  It could be because there are little bits of copper in the cavity from drilling that I need to clean out, or it could be the holes themselves. This is why I hate the idea of drilling into the 3D printed cavity or Oyzw's solid copper cavity.





Offline RonM

  • Senior Member
  • *****
  • Posts: 2628
  • Atlanta, Georgia USA
  • Liked: 1418
  • Likes Given: 1057
I think you should run the experiment first and see if an IR camera can spot signs of resonance. Drilling holes in the cavity for the probe looks like destructive testing to me.

Offline Star-Drive

  • Member
  • Full Member
  • ****
  • Posts: 853
  • TX/USA
  • Liked: 935
  • Likes Given: 17
Here is the first attempt at confirming mode shape using a probe inside the cavity. Of course, it sounds a lot easier than it actually is.  Not only is it hard to know if i'm aligned with the side-wall, small movements with my hand have a huge effect. A probe mount that can slide in and out in a controlled fashion would be very helpful. 

Drilling the holes seemed to have had a very large effect on Q as the RL dip wasn't nearly as narrow after each hole.  It could be because there are little bits of copper in the cavity from drilling that I need to clean out, or it could be the holes themselves. This is why I hate the idea of drilling into the 3D printed cavity or Oyzw's solid copper cavity.   

Jamie:

When trying to confirm resonant modes in the frustum that won't load the cavity, you can either spray paint the exterior of the cavity a flat black then IR camera check the exterior surfaces for temp differentials and/or just use a strip of black vinyl electrical tape along the side wall and across both the small and large OD ends of the frustum as I did at the Eagleworks Lab.  However I do understand that if your frustum sidewalls and endcaps are too thick, that the thermal diffusion of the surface current induced joule heating of the copper side walls and endcaps will make the IR camera resonant-mode monitoring challenging at best. 

BTW, the Eagleworks (EW) Lab's copper frustum sidewalls were 0.024" thick, alloy 110 copper sheet while the endcaps were 0.063" thick, single sided FR4 PC board with 1.0oz per square or ~35.6 micron copper thickness, see attached slides.

PS: These thermal pictures are of the EW copper frustum's 1,937.115 MHz, TM212 resonant-mode.

Best,
Paul M.   
« Last Edit: 06/18/2018 02:56 pm by Star-Drive »
Star-Drive

Tags: