Cannae/EmDrive

[wumpus]

35 minutes ago, Bill Phil said:

Then what about the power supply.....?

Anyhow, more research is required to prove/disprove it.

If I had attached a switching power supply to a microwave-based design that was looking for power levels deep in the noise, I'd be smacking my forehead hard.  While the noise that goes along with the power won't be close to microwave frequencies, things can certainly get amplified and monkey with results.

Better run it again, with a battery.  Even a chain of linear regulators and filters are unlikely to filter the power down to the minute issues that you are looking for (well maybe, but when you are challenging the conservation of momentum and/or similar principles you need to nail *everything* down).

[p1t1o]

@PB666 

@gpisic

Google translate of the conclusion:

Spoiler

1) By measuring device and uncertainty for three wire pendulum thrust
Theoretical analysis and experimental research degree can be found measuring device
Uncertainty mainly from the errors of interpretation of the laser spot. thrust
Less than 3mN, the relative uncertainty of measurement of thrust of more than 14%, while
And with the thrust decreases, the relative uncertainty increases rapidly; therefore, tris
Wire torsion thrust force measuring device measuring range should not be less than
3mN. Improve the reading accuracy of the laser spot, in theory, can significantly improve
Middle wire torsion means load capacity, which is the next step needs to be done
jobs.
The thrust (2) external power microwave thruster experimentally measured
Is 8 ~ 10mN, relative uncertainty is 3.3% ~ 9.2%, measurements
If additional forces by a lot of interference. Independent microwave Thruster Experiment
Measurement less than 0.7mN, relative uncertainty exceed 80% of the measured
The results have not been the amount of additional forces outside interference, the main uncertainty
From the measuring means measuring accuracy.

They do recognise that measurements below 3mN are not admissable and very innaccurate. 

However (if the paper is legit and not government fiction) the paper does report thrust measured at ABOVE 3mN ~(ie: in the accurate range) with external power and error quoted at 14%, and no/very little/unmeasurable thrust detected with the battery, error quoted as 99.6 - 129.7%.

So what they write is at least internally consistent, they do not rule out thrust with the battery, just that it is below their measurable range. Still, you'd expect similar results with the two different power sources, which they did not get. Still very weird that they are operating in milliNewtons and not microNewtons.

If it was micronewtons the whole time, the paper would be very much saying what GPISIC first said it was, give or take.

 

**edit**

They are responsible for what they present, not me, if they present false numbers then the paper itself should be thrown out for carelessness. If they meant 3 microNewtons instead of 3 milliNewtons that is still not adequate when you are measuring 7 microNewtons because your variance would be horrible, like 80%.

Even so, would you expect such different results with two different power sources?

Edited June 30, 2016 by p1t1o
avoid double post

[PB666]

Just now, p1t1o said:

@PB666 

@gpisic

Google translate of the conclusion:

  Reveal hidden contents

1) By measuring device and uncertainty for three wire pendulum thrust
Theoretical analysis and experimental research degree can be found measuring device
Uncertainty mainly from the errors of interpretation of the laser spot. thrust
Less than 3mN, the relative uncertainty of measurement of thrust of more than 14%, while
And with the thrust decreases, the relative uncertainty increases rapidly; therefore, tris
Wire torsion thrust force measuring device measuring range should not be less than
3mN. Improve the reading accuracy of the laser spot, in theory, can significantly improve
Middle wire torsion means load capacity, which is the next step needs to be done
jobs.
The thrust (2) external power microwave thruster experimentally measured
Is 8 ~ 10mN, relative uncertainty is 3.3% ~ 9.2%, measurements
If additional forces by a lot of interference. Independent microwave Thruster Experiment
Measurement less than 0.7mN, relative uncertainty exceed 80% of the measured
The results have not been the amount of additional forces outside interference, the main uncertainty
From the measuring means measuring accuracy.

They do recognise that measurements below 3mN are not admissable and very innaccurate. 

However (if the paper is legit and not government fiction) the paper does report thrust measured at ABOVE 3mN ~(ie: in the accurate range) with external power and error quoted at 14%, and no/very little/unmeasurable thrust detected with the battery, error quoted as 99.6 - 129.7%.

So what they write is at least internally consistent, they do not rule out thrust with the battery, just that it is below their measurable range. Still, you'd expect similar results with the two different power sources, which they did not get. Still very weird that they are operating in milliNewtons and not microNewtons.

If it was micronewtons the whole time, the paper would be very much saying what GPISIC first said it was, give or take.

That's a problem with their set-up, not the Cannae,  The other setups in the US and Europe do not measure that high of an impulse, so that should have been caught by the referees and rejected. Why rejected, their setup up is not an improvement on what has been already published but a digression thereof , which is probably why the paper ended up in a Chinese publication, not an international Journal. I see papers like this 'all the time' and a reject papers like this 'all the time'. The majority of them end up in Chinese publications.

 

[p1t1o]

4 minutes ago, PB666 said:

That's a problem with their set-up, not the Cannae,  The other setups in the US and Europe do not measure that high of an impulse, so that should have been caught by the referees and rejected. Why rejected, their setup up is not an improvement on what has been already published but a digression thereof , which is probably why the paper ended up in a Chinese publication, not an international Journal. I see papers like this 'all the time' and a reject papers like this 'all the time'. The majority of them end up in Chinese publications.

Interesting, so its about as high quality as the rest of the literature I've seen on these things then.

Do you know of any actual, reliable, high-quality papers on these thrusters?

Edited June 30, 2016 by p1t1o
remove redundancy

[PB666]

 

 

This is a pretty different device than has been studied, The microwave sender is in a different location. Their device uses a standard ruler to measure the force.

15 minutes ago, p1t1o said:

Interesting, so its about as high quality as the rest of the literature I've seen on these things then.

Do you know of any actual, reliable, high-quality papers on these thrusters?

At least one of the publications has taken into accounts of major sources of error, seems a reasonable discounting of the critiques but did not produce a causal conclusion.

The more recent papers are theoretical so. . . .

[p1t1o]

@PB666

Has anyone definitively shown that it really produces thrust at least?

[PB666]

3 minutes ago, p1t1o said:

@PB666

Has anyone definitively shown that it really produces thrust at least?

Not until it gets into space. They cannot absolutely rule out interactions with the chamber. Thats essentially the problem, its traps electrons and creates this resonance that may extend out form the chamber, is it inches, feet, yards, or miles. Noone for sure knows.

 

[p1t1o]

@PB666 Guess I'll keep not holding my breath then.

Cheers bud, peace.

[RainDreamer]

Welp, lets send a test nanosat to space and test that. Any chance onr of them get to piggybackride an upcoming launch

[p1t1o]

3 hours ago, RainDreamer said:

Welp, lets send a test nanosat to space and test that. Any chance onr of them get to piggybackride an upcoming launch

Didn't exactly that happen to some Russian satellite or other? Someone purportedly snuck a thruster aboard or something?

[FreeThinker]

A new peer-reviewed paper on the EmDrive from Finland states that the controversial electromagnetic space propulsion technology does work due to microwaves fed into the device converting into photons that leak out of the closed cavity, producing an exhaust.

The research, entitled "On the exhaust of electromagnetic drive", is published in the journal AIP Advances 6 and is the brainchild of Dr Arto Annila, a physics professor at the University of Helsinki; Dr Erkki Kolehmainen, an organic chemistry professor at the University of Jyväskylä; and Patrick Grahn, a multiphysicist at engineering software firm Comsol.

http://www.ibtimes.co.uk/emdrive-finnish-physicist-says-controversial-space-propulsion-device-does-have-exhaust-1565673

Edit: this version also contains some intresting videos

http://www.dailymail.co.uk/sciencetech/article-3644747/Does-Nasa-s-fuel-free-thruster-invisible-exhaust-New-theory-explain-EmDrive-man-Mars-10-weeks.html

Edited August 5, 2016 by FreeThinker

[Bill Phil]

That would make it a photon rocket. The thing about photon rockets is that most of them are gamma ray based...

[p1t1o]

Yeah this concept has already done the rounds on here. It does paint a picture of the EmDrive being a weird way to build what is essentially a focused light (EM) source, however there were discrepancies in the power consumed and the thrust produced - pure photon rockets have huge (something like 300MW per newton) power requirements and the EmDrive appeared to be producing more thrust than it should from its power source - if it was a purely a photon reaction force.

So in other words, yep the whole thing is still up in the air. Whether or not the dang things even produce thrust at all is still not hammered out to full confidence.

This part of that article also weirds me out a bit:

" Annila has been researching the basic principle of nature for the last decade, which states that any difference in energy (i.e. force) will level off in the least available amount of time."

 

Ah, "the basic principle of nature", that well known law of physics we are always referring to! Which can apparently be applied not only to alternative models of the universe that dont include dark matter but also to evolution and...economics?

It just sounds...off.

[Scotius]

Any news about NASA report? Eagleworks team was supposed to publish their finds in 2016. It's august already...

[FreeThinker]

1 hour ago, Bill Phil said:

That would make it a photon rocket. The thing about photon rockets is that most of them are gamma ray based...

Yes but It could be as near effective as a Photonic laser thruster which uses the resonance to extract maximum amount of thrust from light, Effectivly making it up to 1000 as powerfull as a pure photon rocket

so instead of generating 1 newton from 300 MW, it would allow up to 3 kn of thrust. With this kind of propulsion, we are in business.

NASA engine is currenlt only 1.6% efficient, I think they can improve it

 

Edited August 5, 2016 by FreeThinker

[Frozen_Heart]

52 minutes ago, Scotius said:

Any news about NASA report? Eagleworks team was supposed to publish their finds in 2016. It's august already...

They were originally going to publish them summer 2015. I'm pretty sure we aren't going to see anything from them.

[SuperFastJellyfish]

39 minutes ago, Scotius said:

Any news about NASA report? Eagleworks team was supposed to publish their finds in 2016. It's august already...

It didn't make it through peer review was the last rumor I've heard on nasaspaceflight.com, but that was just a rumor, of course.

From here:

Quote

Last I heard, after several re-writes of their copper frustum in-vacuum paper, there is no hope in sight of getting it past the peer reviewers for the Journal in question. Not much else going on, due to budget cuts. It sounds like any work being done is on their own time.

and here:

Quote

Quote from: FattyLumpkin on 07/06/2016 10:45 PM

Quote

Two things: 1) WarpTech, can you tell us what your source of information is re multiple rewrites of the EW paper in now in peer review. To suggest that the paper will probably be denied publication in ? Journal after XXX amounts of rewrites would be a huge revelation. Please tell us the source of your information.
2) Dave intends to use a 250 Watt solid state signal generator/power pack....perhaps the same one that (if memory serves) Monomorphic was speaking of?
TBMK Dave is taking a break for a sort while after countless sixteen-hour build and test days. I'm hoping to see something from him soon...(He did mention a time frame, but it escapes me).

 

I inquired and Paul sent me an update by email. There were no details beyond what I said. I don't like to read minds, but IMO, it sounds to me like the referee wants more data and they don't have the budget to do more testing. Personally, I was more interested in the COMSOL simulations of the quantum vacuum, but it appears nothing is being done on that topic at all. I think if there is any "real" propulsion from a sealed frustum, after all external variances have been taken into account, that push will be due to modifying the quantum vacuum. So understanding how the EM Drive might work, is paramount to understanding how to push/pull against a quantum vacuum.

Unfortunately, without an accepted theory of quantum gravity, Dr. White is practically on his own. Lucky for me, I don't need an accepted theory. I have my own engineering model that works very well, thank you!

Todd

 

[StrandedonEarth]

 

[ImmaStegosaurus!]

Is this "EM Drive" other name for VASIMR?

 

[StrandedonEarth]

30 minutes ago, ImmaStegosaurus! said:

Is this "EM Drive" other name for VASIMR?

 

No. The EM Drive, aka Cannae Drive, used microwaves, and was reported to be the Holy Grail of spaceflight, the fabled "reactionless drive" requiring only electricity and no propellant to produce thrust. It reportedly produced about 10 times the thust/watt of a pure photon drive. If true, then in space it would have freed us from the tyranny of the rocket equation, where simply adding more and more fuel propellants results in diminishing returns. Unfortunately, it seems the thust they were measuring came from an interaction with the power cables, and no thrust was measured when running it on battery power.

VASIMR is a plasma thruster, basically a high-powered ion drive with a magnetic-field nozzle

[ImmaStegosaurus!]

[Jonah-Jameson-Laugh.gif]

We could colonize solar system with what we'll have planned/in operation within next ten years. 

[Nibb31]

2 hours ago, ImmaStegosaurus! said:

[Jonah-Jameson-Laugh.gif]

We could colonize solar system with what we'll have planned/in operation within next ten years. 

In your dreams.

[Vanamonde]

New posts merged into the existing thread for this subject. 

[magnemoe]

4 hours ago, Nibb31 said:

In your dreams.

Yes, even an working EM-Drive would be more like an ion drive who don't need reaction mass, very nice but not an touch ship. 
It would be useful both for satellites, probes and manned missions, manned missions would benefit less and would still need shielding and life support for an long time, main benefit is that it would be easier to visit remote places. 

[Frozen_Heart]

Looks like the NASA paper has passed peer review. Hopefully this either proves or disproves it.