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Re: EM Drive

Posted: Thu May 12, 2016 12:32 pm
by Carl White
Image
Cannae recently completed another successful demo of our superconducting thruster technology. Pictured above is the cooldown of the thruster (located in the steel dewar) with liquid helium. Cannae ran the current prototype in two orientations and saw thrust reversal when the thruster was inverted. More news to come…
http://cannae.com/another-successful-su ... completed/

Very little information, no video. Still waiting for a convincing third party demonstration. :|

Re: EM Drive

Posted: Thu May 12, 2016 7:13 pm
by ladajo
Hmmm. Reversal seen. I hope the report is telling.

Re: EM Drive

Posted: Tue Jun 28, 2016 2:12 pm
by Diogenes
New Paper Claims EM Drive Works, Produces Light As Exhaust



Arto Annila, one of the researchers behind the work, clarified to ScienceAlert: “Light at microwave lengths is the fuel that’s being fed into the cavity … and the EM drive exhausts backwards paired photons. When two photons travel together, but having opposite phases, then the pair has no net electromagnetic field, and hence it will not reflect back from the metal walls, but goes through.”

http://futurism.com/new-paper-claims-em ... t-excited/

Re: EM Drive

Posted: Tue Jun 28, 2016 3:19 pm
by Skipjack
Well, if it is just another photon drive, then it is doomed to have impractically low thrust.

Re: EM Drive

Posted: Tue Jun 28, 2016 4:24 pm
by hanelyp
Diogenes wrote:New Paper Claims EM Drive Works, Produces Light As Exhaust
Arto Annila, one of the researchers behind the work, clarified to ScienceAlert: “Light at microwave lengths is the fuel that’s being fed into the cavity … and the EM drive exhausts backwards paired photons. When two photons travel together, but having opposite phases, then the pair has no net electromagnetic field, and hence it will not reflect back from the metal walls, but goes through.”

http://futurism.com/new-paper-claims-em ... t-excited/
1. That is all very contrary to the well established Maxwell's Equations model of light as a traveling electromagnetic wave.

2. Such a model can explain thrust only on photon thruster levels, which is not nearly enough to be "interesting" unless you have something like a mass conversion device to power the thruster.

Re: EM Drive

Posted: Tue Jun 28, 2016 7:14 pm
by Giorgio
Additionally the thrust that they claim to have observed at those applied power levels cannot be explained by photon thrust.
So either the reading (or measurement set up) is wrong or this theory is not applicable to what's happening there.

Re: EM Drive

Posted: Wed Jun 29, 2016 4:57 pm
by ScottL
If we're discussing the basic emDrive and not assuming the above, the most robust and rigorous experimental result measurements have trended to 0. At this point, most of the hype is gone. If we're now considering the above, then as mentioned, this thing is useless and the numbers are clearly being fudged. I'd also point out that Cannae now offers to test other entity's devices for thrust. I find this most comical. If you have a groundbreaking tech that you're researching, why hold everything to run tests for other people's work? From a break-through standpoint, this seems silly. From a business standpoint, this is pivoting when your original plan didn't work out like you had hoped.

Pivoting:
https://www.youtube.com/watch?v=M1vfXoUNDYA

Re: EM Drive

Posted: Thu Jun 30, 2016 9:24 pm
by JoeP
ScottL wrote:... I'd also point out that Cannae now offers to test other entity's devices for thrust. I find this most comical. If you have a groundbreaking tech that you're researching, why hold everything to run tests for other people's work? From a break-through standpoint, this seems silly. From a business standpoint, this is pivoting when your original plan didn't work out like you had hoped.
Pretty convincing....although they might be doing it to consolidate design ideas in their lab and network with other research teams. But I suppose looking at that tactic, with the same kind of critique in mind, then that also is a bit of an indicator that their stuff isn't really viable.

Re: EM Drive

Posted: Fri Jul 01, 2016 12:28 am
by zapkitty
JoeP wrote:
ScottL wrote:... If you have a groundbreaking tech that you're researching, why hold everything to run tests for other people's work?
....although they might be doing it to consolidate design ideas in their lab and network with other research teams.
I was thinking more along the lines of Cannae hunting up cash payments on some rather expensive lab gear while rebuilds of their engines are underway... that wouldn't nullify Scott's point but it also wouldn't require outright fraud on the part of Cannae.

Re: EM Drive

Posted: Fri Jul 01, 2016 3:14 pm
by kunkmiester
My brother pointed out torsion pendulums capable of handling that kind of weight while still holding the necessary accuracy shouldnt be too terrobly common or too easy to make--most low thrust systens lIke Hall effect thrustern arent nearly as big. It would be sensible having spent some time and effort to build it to share it, especially if you can get some revenue out of it.

Of course all the other stuff does too.

Re: EM Drive

Posted: Fri Jul 01, 2016 4:29 pm
by ScottL
kunkmiester wrote:My brother pointed out torsion pendulums capable of handling that kind of weight while still holding the necessary accuracy shouldnt be too terrobly common or too easy to make--most low thrust systens lIke Hall effect thrustern arent nearly as big. It would be sensible having spent some time and effort to build it to share it, especially if you can get some revenue out of it.

Of course all the other stuff does too.
I think it depends on the build design of the test platform. If it is an intelligently designed test platform, they would recognize that they aren't measuring thrust, but instead measuring the combination of any anomalous forces and any undesired forces as well. The test platform alone cannot eliminate error, it can only provide a measurement. In this case, it's trivial to for experimenters to setup their test platforms to support various orientations that reliably help quantify some of those undesired effects. The best example I can think of would be thermal effects in a vertical orientation vs horizontal orientation. Just some food for though, but I don't think you need to spend a fortune on these test platforms. They're trivially simple in many cases.

Re: EM Drive

Posted: Mon Aug 22, 2016 8:24 pm
by Carl White
"Cannae is deploying a cubesat thruster"

http://cannae.com/cannae-is-developing- ... -thruster/

Full text:
Cannae is forming a new company to commercialize Cannae thruster technology for use on small satellites. Theseus Space Inc. will use Cannae thruster technology to maintain (for a minimum of 6 months) the orbit of a 6U cubesat flying below a 150 mile orbital altitude. Theseus will launch the satellite within 24 months and will use an existing satellite integrator for the build and launch of the cubesat. LAI International remains a key partner in Cannae thruster development and project management. More news to follow.
At last one is going to be put into space. One way or another, the issue will be resolved.

Re: EM Drive

Posted: Mon Aug 22, 2016 11:18 pm
by ScottL
Carl White wrote:"Cannae is deploying a cubesat thruster"

http://cannae.com/cannae-is-developing- ... -thruster/

Full text:
Cannae is forming a new company to commercialize Cannae thruster technology for use on small satellites. Theseus Space Inc. will use Cannae thruster technology to maintain (for a minimum of 6 months) the orbit of a 6U cubesat flying below a 150 mile orbital altitude. Theseus will launch the satellite within 24 months and will use an existing satellite integrator for the build and launch of the cubesat. LAI International remains a key partner in Cannae thruster development and project management. More news to follow.
At last one is going to be put into space. One way or another, the issue will be resolved.
A fool and his money are soon parted. The claimed thrust compared to what is required to maintain orbit are telling.

Re: EM Drive

Posted: Tue Aug 23, 2016 12:44 am
by hanelyp
A clearer test result would be if the thruster could measurably raise the orbit, not just counter drag with a great deal of variation at the altitude in question. The cynic in me questions if this sub-standard test is deliberate, when a proper test at higher altitude would not be much harder.

Re: EM Drive

Posted: Tue Aug 23, 2016 11:58 am
by RERT
Can you quote me their claims of thrust? There are no press releases on their website with any claims that I can see.

The force required to maintain orbit is not high (I think 30-230 micronewtons), but this has to be sustained over six months. If they are determined to cheat, they can certainly do that with off-the-shelf cubesat thrusters.

Without thrust, I believe the thing would fall to earth in a few days from 150 miles. Though small, the drag at that altitude is high by orbital standards: going down from 400km LEO to 240km greatly increases the drag. If there is nothing but an EMdrive on the satellite, you actually have a very quick test result, if you believe they are not cheating.

If it flies for long enough, the drive is categorically working, whether or not you think they might try to cheat. Lowering the flight altitude shortens the duration of 'long enough'. A determined skeptic might need some years to be convinced, I guess.

Why would they spend the money to put it in orbit without having measured ample thrust for the mission in the lab?

They could maybe be crazy and/or crooked, like Rossi, but let's hope not.