EM Drive

Point out news stories, on the net or in mainstream media, related to polywell fusion.

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quixote
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Re: EM Drive

Postby quixote » Fri Sep 02, 2016 10:54 pm

ScottL wrote:If memory serves, EW later removed the dielectric since it had no appreciable effect and proceeded with the vacuum test with a design more similar to Shawyer's.

Per the emdrive wiki and comments on NSF, NASA only produced results when using an HDPE extruded dielectric.

http://emdrive.wiki/Experimental_Results

birchoff
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Re: EM Drive

Postby birchoff » Sat Sep 03, 2016 5:11 am

ScottL wrote:
birchoff wrote:I think the part that your missing in your analysis is that the EagleWorks setup is different. Shawyer/Yang and quite a few of the DIY are all running frustums with no die electric in them. While the EagleWorks and Cannae versions have die electrics in them. While I have no clue what effect the die electrics would have. I am 100% certain that the paper that is being talkd about includes positive results after doing work to remove additional sources of error. I suspect there wont be any discussion of theory in the paper as that sounded like it was the reason this paper took so long to come out. But if it did include some theory that would be even more interesting. Personally I am on the side of their being something there. The only question is can it be used for propulsion. That said if real the most interesting thing isnt the propulsion but using it as a way to learn more about how nature works.



I think you may be mistaken or behind on the happenings. EW's original work consisted of a frustum similar to Cannae's, however; their control appeared to have the same measurement (the null result) as the live test. If memory serves, EW later removed the dielectric since it had no appreciable effect and proceeded with the vacuum test with a design more similar to Shawyer's. Of course when you put electronics that aren't rated for vacuum in a vacuum, you can get odd results and they ended up blowing their RF amp if I'm not mistaken.

Until we see a design, it's hard to make a call, but given the lack of theory and the nullification of many other previous results, it's not looking good.


Umm.. I think you are mistaken.

The very first conference paper that Eagle Works published was for their experiment using a Frustum similar to shawyers but it had a Dielectric insert in it. Whites entire theory for why the thing works is based on the need for that Die electric insert. They also included the results from testing the Cannae device and proposed that the reason the null configuration of the Cannae device failed (showed propulsion) was because it still had a dielectric in it. Now Paul March has discussed on NSF about the issues they have had with some bolts melting during their testing but at no time have they ever said they are moving away from using a Die electric insert in the small end of their frustum.

I have been following the discussion on emdrive fervently since that AIAA conference paper both here and on NSF (Since Thread 1). Before then I was merely familiar with what Roger Shawyer was proposing but figured it was experimental error. Now it is true that their follow up test run after the AIAA paper met with problems using non vac rated parts in hard vacuum. But they retooled and acquired vac rated versions and re ran the tests. So like I said before the EW research is different because they are assuming that a critical part of generating thrust is the die electric. IIRC, I believe it was Paul March on NSF who said they tried without a dielectric and got no thrust. So there is ample evidence on the NSF threads to prove that they are using a Die Electric as of the last time Paul graced that forum.

birchoff
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Re: EM Drive

Postby birchoff » Sat Sep 03, 2016 5:18 am

Carl White wrote:Good to hear. My predictions, for what they're worth:

1. The paper won't settle the controversy.

2. Just possibly they'll be able to report reproduction by another group in NASA.

3. Skeptics will continue to attack the experimental apparatus and the signal to noise.


Agree with 1

Disagree with 2.... If they did that in this paper that would be huge. However I suspect the results in this paper will set the stage for the replications they talked about in that first AIAA conference paper.

Agree with3... Haters gonna hate. Not much you can ever do about that. Unfortunately if this result is from the test run Paul March talked about while they did work to eliminate lorentz and took measurements to quantify how much lorentz they were getting. It sounded like they had to resort to numerically removing the force contributions of thermals. So I expect alot of heated debate about that part.

Overall, I think we will get more outlandish statements from Shawyer. Plus this kinda sets the stage for Cannae's 6 month cube sat demonstration.

Giorgio
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Re: EM Drive

Postby Giorgio » Sun Sep 04, 2016 2:47 am

I would have preferred if they actually placed it into a trans-lunar orbit and make it flight halfway in a 8 shape with several stops and reverse in directions. Make it for few month and that would have been quite an unobjectionable proof of work.

Over the year that they have been testing this device, it has gone from N/Kw of thrust to mN/Kw and than to uN/Kw. Not a good indication.... Additionally until now the theory behind it is still quite weak, so I am quite curious to see the set up and what the result will be.
And hopefully this news release is not connected to the "looking for serious investors" notice that is present on their website........ I really don't want to see another Mr. Rossi or Blacklight nonsense.
Look, stars!

paperburn1
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Re: EM Drive

Postby paperburn1 » Sun Sep 04, 2016 12:23 pm

So are they claiming a special frame of reference for their device?
And the faster this goes the less efficient it becomes?
(note: keep it simple I barely understand this stuff)
I am not a nuclear physicist, but play one on the internet.

zapkitty
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Re: EM Drive

Postby zapkitty » Sun Sep 04, 2016 12:38 pm

Georgio, paperburn... are you referring to Cannae, SPR or Eagleworks?

Giorgio
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Re: EM Drive

Postby Giorgio » Sun Sep 04, 2016 1:42 pm

zapkitty wrote:Georgio, paperburn... are you referring to Cannae, SPR or Eagleworks?

I'll be honest, I didn't follow up Eagleworks closely so I will refrain on commenting on them until i see some more reports. My original comment was referred to SPR and Cannae. The first claims for both was quite bold, even in the N/few kw range, while following reports slide into lower and lower result. Should be the opposite...

Add to this that the suggested test is "ok" but 100's of issues can happen (or invoked) to prevent a final and conclusive result. With a little bit more of effort they could have made an experiment that could have removed any doubts. This attitude is so similar to Mr. Rossi and I don't like it, but anyhow, let's see and hope that I am wrong.
Look, stars!

hanelyp
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Re: EM Drive

Postby hanelyp » Mon Sep 05, 2016 4:40 pm

paperburn1 wrote:So are they claiming a special frame of reference for their device?
And the faster this goes the less efficient it becomes?
(note: keep it simple I barely understand this stuff)

So far as I can work out, something like that is the only way a reactionless drive with performance better than a photon rocket can be sure to avoid non-conservation of energy. Similar performance wise would be the thruster pushing on mass outside.
The daylight is uncomfortably bright for eyes so long in the dark.

ScottL
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Re: EM Drive

Postby ScottL » Tue Sep 06, 2016 4:56 pm

birchoff wrote:Umm.. I think you are mistaken.

The very first conference paper that Eagle Works published was for their experiment using a Frustum similar to shawyers but it had a Dielectric insert in it. Whites entire theory for why the thing works is based on the need for that Die electric insert. They also included the results from testing the Cannae device and proposed that the reason the null configuration of the Cannae device failed (showed propulsion) was because it still had a dielectric in it. Now Paul March has discussed on NSF about the issues they have had with some bolts melting during their testing but at no time have they ever said they are moving away from using a Die electric insert in the small end of their frustum.

I have been following the discussion on emdrive fervently since that AIAA conference paper both here and on NSF (Since Thread 1). Before then I was merely familiar with what Roger Shawyer was proposing but figured it was experimental error. Now it is true that their follow up test run after the AIAA paper met with problems using non vac rated parts in hard vacuum. But they retooled and acquired vac rated versions and re ran the tests. So like I said before the EW research is different because they are assuming that a critical part of generating thrust is the die electric. IIRC, I believe it was Paul March on NSF who said they tried without a dielectric and got no thrust. So there is ample evidence on the NSF threads to prove that they are using a Die Electric as of the last time Paul graced that forum.



That's the difference between Cannae and Shawyer's designs, the insert, so I would say they followed a Cannae design, not Shawyers per se. I know Paul mentioned some arcing problems in those designs though, so I would take issue with relying on those results\designs. I can't say definitively if EW is still using inserts or not because Paul isn't saying much on NSF or elsewhere. The last post he had was "we still see a signal," but did not mention any specifics, so there is no point in speculating. I was under the impression by the time they rolled around to the vacuum test they had eliminated the inserts as a possible source and had switched to Shawyer's design, but getting an impression from posts is difficult at best.

Personally, I'm waiting on the paper as I think Shawyer is mistaken much like Yang was until she corrected her experiment. I suspect that once published, EW's paper will receive proper critique, but I can't say whether EW will follow through with corrections to their design (low funding after all.) My fear is that they decide to focus on something else after the paper, having served it's purpose to drum up some funding, and we're stuck in limbo.

ScottL
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Re: EM Drive

Postby ScottL » Tue Sep 06, 2016 4:58 pm

Giorgio wrote:
zapkitty wrote:Georgio, paperburn... are you referring to Cannae, SPR or Eagleworks?

I'll be honest, I didn't follow up Eagleworks closely so I will refrain on commenting on them until i see some more reports. My original comment was referred to SPR and Cannae. The first claims for both was quite bold, even in the N/few kw range, while following reports slide into lower and lower result. Should be the opposite...

Add to this that the suggested test is "ok" but 100's of issues can happen (or invoked) to prevent a final and conclusive result. With a little bit more of effort they could have made an experiment that could have removed any doubts. This attitude is so similar to Mr. Rossi and I don't like it, but anyhow, let's see and hope that I am wrong.


I agree with you 100%. I don't believe Shawyer's intent is to create a Rossi trainwreck, but you never really know.

zapkitty
Posts: 267
Joined: Fri Apr 09, 2010 8:13 pm

Re: EM Drive

Postby zapkitty » Tue Sep 06, 2016 9:25 pm

ScottL wrote:
Giorgio wrote:
zapkitty wrote:Georgio, paperburn... are you referring to Cannae, SPR or Eagleworks?

I'll be honest, I didn't follow up Eagleworks closely... My original comment was referred to SPR and Cannae...


I agree with you 100%. I don't believe Shawyer's intent is to create a Rossi trainwreck, but you never really know.


Well, with 2 companies, at least 3-4 government and/or university based labs, an unknown number of DIYer hobbyists and 3.1415x10^17 media sources all circulating design concepts, physics ideas, news reports, test data, misconceptions and misunderstandings with equal abandon it is absolutely necessary to be specific or all is lost :)

That said, I get it about Cannae now, after going over their spacecraft concepts... Dr. Rodal made some good points about the "space tug" thermal design on NSF after he confused it with Cannae's cubesat experiment.... but he seems to have missed the most egregious example: the Cannae "space probe"

http://cannae.com/deep-space-probes/

The "space probe" stated goals and specs vs the physical design made me go "WTF?" The design hinges on using the collective, and rather large, surface area of the drives as radiators to bring down the drive temps to HTSC levels...

... but the configuration inherent to Cannae drive design requires that almost all of that surface area to be facing other drives at close range rather than facing deep space.

I can now understand why Cannae seems to be regarded as an... opportunistic... enterprise by many.

Carl White
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Re: EM Drive

Postby Carl White » Wed Sep 07, 2016 5:25 pm

zapkitty wrote:... but the configuration inherent to Cannae drive design requires that almost all of that surface area to be facing other drives at close range rather than facing deep space.


Why can't they be spread out? More surface area perpendicular to the axis of motion + significant fraction of light speed = danger from dust particles?

paperburn1
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Re: EM Drive

Postby paperburn1 » Wed Sep 07, 2016 10:04 pm

Carl White wrote:
zapkitty wrote:... but the configuration inherent to Cannae drive design requires that almost all of that surface area to be facing other drives at close range rather than facing deep space.


Why can't they be spread out? More surface area perpendicular to the axis of motion + significant fraction of light speed = danger from dust particles?
you can stop that with Whipple shields
I am not a nuclear physicist, but play one on the internet.

zapkitty
Posts: 267
Joined: Fri Apr 09, 2010 8:13 pm

Re: EM Drive

Postby zapkitty » Thu Sep 08, 2016 7:33 am

Carl White wrote:
zapkitty wrote:... but the configuration inherent to Cannae drive design requires that almost all of that surface area to be facing other drives at close range rather than facing deep space.


Why can't they be spread out? More surface area perpendicular to the axis of motion + significant fraction of light speed = danger from dust particles?


Would work with a long enough spacecraft spine, but the drive faces are represented as just a few degrees off perpendicular to the spine axis (maybe 10 degrees?) so to significantly reduce the number of thermal photon bounces you'd have to add a LOT of spine mass... double it or more?

That's a lot of added mass for a low thrust drive.

At some point, and fairly quickly I think, it'd be more economical to add straight-up thermal control surfaces.

paperburn1
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Joined: Fri Jun 19, 2009 5:53 am
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Re: EM Drive

Postby paperburn1 » Thu Sep 08, 2016 3:51 pm

sorry missed the 400 pound gorilla in that last post.
I am not a nuclear physicist, but play one on the internet.


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