EmDrive

[Jesrad]

The late July tests of the Cannae drive and EmDrive-like non-slotted (="null") thruster were done by NASA at 5x10^-6 Torr (~0.1 mBar ?) of atmospheric pressure. That's some decent vacuum. They both produced thrust.

Edited August 19, 2014 by Jesrad

[KerikBalm]

Please provide the source, I am curious to know if this is the case.

Of course, as I mentioned in a much earlier post, I'm still curious if the force could be explained by interaction with earth's magnetic field.

The magnetic field is already used to produce torque on spacecraft to desaturate reaction wheels and such, and they were actually measuring torque, which they attributed to thrust

[Mazon Del]

To be fair, there is equal evidence that it could be magical pixies.

To claim it as evidence of a working EM drive/quantum virtual particle/whatever thruster is extremely unscientific. The results do not support any conclusion.

There is no evidence to refute a null hypothesis of the thrust being produced by heating of air.

This test shows no evidence that the thing works. End of Story until they do a proper test. There is no need to go into space to do a proper test at this time

Look, I've got to say that you have gone after others by declaring strawman arguments and yet your example here is the BIGGEST one to date. Additionally one can declare your post about M Drive's statement was the "Attack of Character" fallicy. Attacking the person, however indirectly, rather than addressing the valid points raised by his argument.

Right now the results indicate that thrust is being generated somehow, and I never claimed in the statement that you quoted that it was a working EM drive/quantum virtual particle/whatever thruster. My point was that if the working model produces thrust, and the designed to fail model produces thrust, then the possibility MUST exist that the mechanism by which the thrust is being generated does not necessarily operate as the theory that was used to design the fail model suggests.

I do agree there is no need to go to space as of yet primarily because they can confirm more cheaply here on the Earth.

[KerikBalm]

Look, I've got to say that you have gone after others by declaring strawman arguments

- Modify the last part to read: "other's arguments by pointing out the strawman arguments" , and it would be correct.

Additionally one can declare your post about M Drive's statement was the "Attack of Character" fallicy. Attacking the person, however indirectly, rather than addressing the valid points raised by his argument.

One can declare anything they wish, but unless they provide reasoning to back it up, then they probably face the logical fallacy of an unsupported assertion. My assertions were supported.

I did address his points, I pointed out the strawman claims and explained the distinction between what I said, and his strawmen. I provided an example of heating air producing thrust, and how its conceivable that the "EM drive" could produce thrust in a similar same way.

Do you wish for me to elaborate on his burden of proof fallacy? He is asking me for proof that it could be heating of air producing the thrust as one of multiple explanations, but offers no proof when he implies this shows a a violation of conservation of momentum.

Right now the results indicate that thrust is being generated somehow, and I never claimed in the statement that you quoted that it was a working EM drive/quantum virtual particle/whatever thruster.

I thought it was implied that "the effect" you were referring to was one of the ones that was claimed by the builders - or at least one which violates the conservation of momentum, as it was a followup to my post containing the statements:

"The test was not performed in a vacuum, thus heating of air is a potential source of the thrust

So, the deal is that there is a lot of jumping to conclusions and media hype, and that this thing still probably doesn't work. "

I don't know what other effect you could be referring to, please elaborate on what you meant. I did not intend to misrepresent your views.

Even if that was not your view, my point still stands that its not evidence for *any* explanation for the force, and regardless of what effect you were referring to, the pixie dust has equal weight. Your "to be fair" comment certainly seemed like an appeal to ignorance to get us to accept the premise that this might be evidence of a reactionless drive, hence my need to counter with a "to be fair" comment of my own.

My point was that if the working model produces thrust, and the designed to fail model produces thrust, then the possibility MUST exist that the mechanism by which the thrust is being generated does not necessarily operate as the theory that was used to design the fail model suggests.

Very well, I would modify the statement "does not necessarily operate as the theory that was used to design the fail model suggests." to "must necessarily not operate as the theory that was used to design the fail model suggests."

By the way, asymetric air heating does not operate as the "theory" of Shawyer and his ilk suggest.

Edited August 19, 2014 by KerikBalm

[TheGatesofLogic]

Bring your socratic logic somewhere else, it causes people to become hostile and assume you are trying to act demeaning towards them, a rational discussion does not require a logical antithesis to every mistake, it requires merely cooperative parties on either side of the argument. You are not helping in that regard.

In my opinion the torque measured is undoubtedly real, however the source of the torque ought to be the sole focus of further experiments. Theories that propose thrust as a result of the geomagnetic field are the most likely answer given the data thus far, however thisdoes not mean that they are the only answers available to us. Not until some model accurately describes every aspect of this machine's behavior and the experiments designed to verify these behaviors have the highest reliability will we know for certain.

[Mazon Del]

One is allowed to use an analogy in an argument, I saw the point he was attempting to make with the reference to the ornament which was actually a reference to a device that can have a non-obvious source of locomotion that people could reasonably be uncertain and incorrect about. The comment(s) of the pixie dust are blatant strawman arguments by comparison simply because you will NEVER find a credible physicist that would offer up pixie dust as a valid possible solution (Caveat: This assumes pixies don't suddenly become real creatures with magic powers). Which is an exaggeration of such unrealistic proportion that by tying it in as an equivalent theory to the proposed ones is almost by definition how a strawman argument operates. Even if it was not your intent it provides the declaration that the theory is impossible, simply because pixie dust is also impossible, which is an unhelpful comment to make in a scientific setting because it makes the very idea of considering a given theory that HAS A CHANCE at being true, suddenly foolish and idiotic.

One of the big issues at hand is that a vast majority of nay-sayers instantly declare that heating of the air was the source of the thrust and almost violently declare that all research must come to a close and the idea to never be visited again because the 'solution' has been 'found'. That is not how science works. If you assume that heating of the air was the source of the thrust, then fine, perform a test without appreciable air or a high grade thermal camera observing. If that provides information to allow for the creation of the thrust, then congrats you have solved the issue. If not, then something else (whatever it might be) is in play.

The 'effect' that I was describing was simply the generation of thrust. Regardless of how that thrust was generated, thrust was clearly generated.

I would state that changing "does not" to "must not" is too far. For example, the model could be completely correct, except for a piece you are missing. This doesn't make the model untrue, simply incomplete. To declare the possibly incomplete model a 100% failure because of its inability to predict an outcome perfectly would be foolish as you would then need to strike out a good bit of physics. We haven't discovered everything about physics. Approaching it with great skepticism and analysis to verify claims, it is quite possible to discover an aspect of physics as yet unknown to us. This engine could very well be such a thing, but as I said, great skepticism and analysis should be employed.

Now, I agree with TheGatesofLogic (and his amusingly apt name for this) that utilizing the "fallicy declaration" is generally considered hostile and tends to be less productive. What is more productive when presented with an analogy that has gone too far is to attempt to provide a better analogy that more clearly replicates the desired concept. That way the conversation is able to progress without degenerating into what is effectively educated snooty declarations of "No! Yooou are stupider!".

Edited August 19, 2014 by Mazon Del

[KerikBalm]

I saw the point he was attempting to make with the reference to the ornament which was actually a reference to a device that can have a non-obvious source of locomotion that people could reasonably be uncertain and incorrect about.

I saw it as an appeal to ridicule, but I suppose that is open to interpretation. His phrasing "how's that supposed to work", in the context, made it seem like he was ridiculing the idea.

The pixie dust was not a strawman, it was perhaps an appeal to ridicule. I will note I wasn't presenting it(or at least did not intend to) as an equivalent theory. I was making a statement on the evidence we have.

Perhaps a more nuanced statement would be something like: "at the moment, we have equal evidence for the explanations of: heating of air, interaction with the magnetic field, quantum virtual plasma interactions, and pixie dust - that is to say, we have no evidence."

In this case I certainly would not intent the first 2 explanations to be considered equally plausible to the 3rd, or the 4th. The pixie dust comment was merely to emphasize that we have NO evidence for the cause of the torque - its to emphasize that these results do not constitude evidence that we can make reactionless drives.

"pixie dust is also impossible" - maybe, maybe not, if our universe is a simulation, the rules can change quite durastically, and most will agree its possible that our world is a simulation, the various programmers and users would be in effect dieties and magical creatures. I'll rank this as possible, but given the lack of evidence, I'm not going to start believing it is true.

One of the big issues at hand is that a vast majority of nay-sayers instantly declare that heating of the air was the source of the thrust and almost violently declare that all research must come to a close and the idea to never be visited again because the 'solution' has been 'found

I hope you do not include me in that group. I don't want to imply that it is heating of air, or the torque is due to magnetic field interaction like the needle on a compas.. or whatever.

What I do want to do, and I hoped it was clear based upon my first post (I think it was my first, the reference to arsenic life), is stop people from jumping to unlikely conclusions and spreading undue hype.

People jumping to conclusions results in essentally "lies" being repeated over and over again after they've been shown to be untrue, because the initial astounding claim gets hype, and the refutation is never picked up by the laypeople.

We still have people (on these forums no less), that think we've found bacteria that replace P with As in their DNA, for example.

We still have movies that repeat this "humans only use 10% of their brain" BS (I'm looking at you, Lucy and Limitless!). It annoys me, greatly. I see it as evidence of how easily people will believe BS on faulty logic and bad evidence, which then transfers over to politics and such (oh help me, I almost confirmed Godwin's Law! I was tempted to bring up... never mind) - I think a lot of the world's problems are cause by this sort of irrational jumping to conclusions.

Don't jump to conclusions.

We have a device, it produces a torque on the measuring device when electricity is supplied. Its probably a pretty standard explanation, but some people think it may be because of something extraordinary. So far, there is no extraordinary evidence.

Be patient, wait for more evidence, don't start making extraordinary claims now!

To a lesser extent: lacking extraordinary evidence, and given that cheaper tests can be done to get some evidence, I do not support expending a lot of resources on a more expensive test when a cheap one should suffice.

[TheGatesofLogic]

Now, I agree with TheGatesofLogic (and his amusingly apt name for this) that utilizing the "fallicy declaration" is generally considered hostile and tends to be less productive. What is more productive when presented with an analogy that has gone too far is to attempt to provide a better analogy that more clearly replicates the desired concept. That way the conversation is able to progress without degenerating into what is effectively educated snooty declarations of "No! Yooou are stupider!".

Learned that very lesson actually as a result of choosing this username.

Now, i think we can't reasonably make judgment regarding the device insofar as we lack all the required tests and data. We might, however, be able to compile a sequential list of the most likely scenarios firstly assuming that physics behaves as our current systems predict, and lastly assuming that physics behaves radically different in the immediate vicinity of the device. There is a non-zero chance for this to be a real reactionless thruster, but it would ultimately be expected to be a low end statistic. Ultimately we need more data and more tests to be certain.

[Mazon Del]

I'd accept your statement of the listing of things ending in pixie dust.

Further, though I personally am leaning towards the Simulated Universe more than any other belief system, I feel at this point we've been largely stable enough that it is unlikely the simulators are going to patch pixie dust in. Though honestly if they brought in a magic system, I'd be pretty ok with that.

It is not so much that I include you in that group, as it is that the idea of the thrust just being heated air has been somewhat tainted by those people. Not to say it isn't a possibility, just I've noticed that people on the opposite side of that argument have been getting a bit more heated lately in response to the vehemence with which that argument is being made. I am sure I am no less susceptible to this than anyone else.

Yeah the 10% thing is pretty painful. Mostly my massive interest in this engine tech is that I know its going to be proven one way or another in a couple months without my input, so I might as well fantasize about what the tech can be used for and do if it turns out to be real. ^^

Usually when I make an extraordinary claim about the tech, I am referencing the EMDrive guy that thinks his gen 2 version will be able to make 3.3 TONS of thrust on 1 kilowatt of input energy. I also mention how I am pretty certain this is not going to be the case....but I really hope it is regardless.

As far as expenses in the test, it is a matter of scale really. If it costs 20 million to throw this up into orbit to test, 50 thousand to test any given parameter in isolation on the ground, and 3 million to test all the parameters on the ground. Then if only because of the time it saves you, it is best to do the 3 million test. Remember, this isn't just about proving the engine is real. If they proved it was real now, vs eight months from now, millions will have been saved on various satellites and such from dropping the standard engines. Of course it won't be an immediate adoption, but it would be the technologies "Chicago Pile" moment and you would see a nigh exponential (in the short term) explosion of R&D into the tech, so the sooner we hit that moment, the better, even if you waste say 2 million that you could have saved doing all the tests in isolation over most of a year.

[KerikBalm]

Much like playing the lotto, you should weigh the benefits of success against the probability of success.

I would *love* for these claims to be real. It would be so darn awseome... but... so would winning the lotto... and I don't expect to be lucky enough to win the lotto.

I hope its real.

I doubt its real.

[Mazon Del]

Seems safest, but it isn't really for us to judge if they should or should not do it, I'll trust the judgement of the guys at NASA over it.

[Mazon Del]

I decided on curiosity to look up what Wikipedia had entered about the EMdrive and the cannae drive. It gave me some info that I haven't quite seen stated elsewhere.

http://en.wikipedia.org/wiki/Cannae_drive#Cannae_drive

Namely this line "According to the technical report, both Cannae drives (the standard and the supposed null-test device) produced about the same net thrust. The experimental control measured zero thrust as expected."

The null-test device wwas not intended as the experimental control. The man who invented the Cannae drive (named Fetta) developed a mathematical theory for how to design the engine. It relied upon these radial slots in the rim of the interior of the cavity. His math stated without them no thrust could be generated. The normal Cannae drive had the slots, the null-test device did not. So basically what happened was that they had one engine that was supposed to work, it did. They had another engine that was supposed to fail, it failed. Then they had another engine that if it worked proved that Fetta's models on the engine were flawed, it worked.

Additionally the page declares that the EMdrive experiment is being redone sometime in the next couple months with vacuum rated components, and then they will test in vaccum. They predict the vacuum will change nothing because the tests already done showed effectively instantaneous activation and deactivation of thrust following power up and down. Instantaneous like how a lightbulb is 'instantaneous'. Not physics breaking instant. Anyway, if the effect could not have been caused by the heating of atmosphere because if this were true you would have seen a delayed but gradual increase in thrust once activated (as the components warmed up to the power), followed by a delayed but gradual decrease in thrust after the engine was turned off. This gradual increase/decrease was not observed. Upon completion of the new version, they will create a test article which they will ship out to several major universities and labs for verification.

[M Drive]

The plot thickens. Great news, digging that up, Mazon.

[KerikBalm]

"The null-test device wwas not intended as the experimental control. The man who invented the Cannae drive (named Fetta) developed a mathematical theory for how to design the engine. It relied upon these radial slots in the rim of the interior of the cavity. His math stated without them no thrust could be generated. The normal Cannae drive had the slots, the null-test device did not."

Its obvious that it was designed as a control, the way they describe it is exactly as a control.

This is an after the fact declaration - your control doesn't work, say its not the control! problem solved.

"So basically what happened was that they had one engine that was supposed to work, it did. They had another engine that was supposed to fail, it failed. Then they had another engine that if it worked proved that Fetta's models on the engine were flawed, it worked."

No, they did not have an "engine" that was supposed to fail and then did fail, they had a resistor. The resistor provided no thrust... whoppedy do, thats not a very good control.

[Z-Man]

No, they did not have an "engine" that was supposed to fail and then did fail, they had a resistor. The resistor provided no thrust... whoppedy do, thats not a very good control.

It is a good control for a limited but important set of possible false positive effects, things the Chinese team completely failed to address. For example, what if the wave guide used to feed the power to the resonator causes the thrust once it is powered on, or the electronic components also mounted on the rotating frame? The resistor test mostly excludes that possibility. Any measured effect comes from the cavities.

And yes, the immediate response pretty much rules out thermally induced air currents. My personal shortlist of ordinary explanations:

1. Interactions with the Earth's magnetic field. Essentially, if you have a metal plate and put some AC through it and a magnetic field is present, the field is going to "deflect" the current and cause eddies. Those will have a unidirectional magnetic moment (the magnetic field breaks time reversal symmetry, that's why this is allowed to happen), which then interacts with the magnetic field again and cause a torque.

2. Near field effects. Less likely because cavities even made out of paper-thin copper are quite good at completely containing GHz waves, and near field effects would require some radiation to escape. They'd need to tunnel through leaky seams or escape via...

3. Vibrations. A very long shot, but there will be oscillating stress on the cavity walls. They are in the GHz range initially which would be strongly damped, but apparently GHz sound is something that exists and has been researched.

[KerikBalm]

"And yes, the immediate response pretty much rules out thermally induced air currents"

Well, I suppose that depends on what you mean by air currents and immediate.

I don't know many details about the test or the data.

Convection within the test chamber would take a while.

However, heating within the "resonating" chamber (its my understanding that one end is open), could essentially act like a rocket, heat the propellant, the propellant escapes and produces thrust, the response would be pretty immediate.

Since I don't have access to the design schematics or the data, I'm just speculating here.

If they made a theory about how it works, requiring these slots, and the presence of the slots has no effect, that is good evidence that their theory is wrong, that their explanation is wrong.

Then there is still the torque, for which we don't have an explanation for... An appeal to ignorance may lead to the supposition that there is a very similar effect to the theorized one, but we just don't understand the details...

but as I previously said, we have equal evidence for any number of explanations, including pixie dust - ie, None.

[Z-Man]

However, heating within the "resonating" chamber (its my understanding that one end is open), could essentially act like a rocket, heat the propellant, the propellant escapes and produces thrust, the response would be pretty immediate.

That doesn't work for a couple of reasons. Microwaves do not heat the air, they heat the metal of the cavities. That then would need to heat the air, which happens with a delayed response. Then the heated air does not escape immediately, it only escapes at a speed proportional to the pressure differential, which only slowly builds up as the temperature rises. And from what I read, the cavities of the Cannae thing are quite tightly sealed up, any holes would be tiny. So there would be a delayed response, too.

Also, if thermal expansion produces thrust somehow here, there should be an opposite thrust while the device cools down. Maybe too small to measure, it does not need to be symmetrical. And the thrust should vanish once everything is heated up to equilibrium. I can't say whether they left the devices on for long enough to rule that out, though.

[Mazon Del]

"The null-test device wwas not intended as the experimental control. The man who invented the Cannae drive (named Fetta) developed a mathematical theory for how to design the engine. It relied upon these radial slots in the rim of the interior of the cavity. His math stated without them no thrust could be generated. The normal Cannae drive had the slots, the null-test device did not."

Its obvious that it was designed as a control, the way they describe it is exactly as a control.

This is an after the fact declaration - your control doesn't work, say its not the control! problem solved.

"So basically what happened was that they had one engine that was supposed to work, it did. They had another engine that was supposed to fail, it failed. Then they had another engine that if it worked proved that Fetta's models on the engine were flawed, it worked."

No, they did not have an "engine" that was supposed to fail and then did fail, they had a resistor. The resistor provided no thrust... whoppedy do, thats not a very good control.

Really this experiment was two experiments at the same time. First, does the Cannae drive work (compare standard version and the RF load version [control]). Second, assuming the cannae drive works, does this variant that the math says should fail, fail? (comparing the slot-less drive with the standard cannae drive [control].)

The point of the RF load was as Z-Man pointed out, they wanted to dump the energy using all the backend stuff used in the other tests so they could verify it wasn't somehow the backend stuff causing the thrust.

As far as how the slots work, I am uncertain if they are actually "holes" or if they are more like pits. Imagine the bottom of your standard plastic soda bottle. I imagine it is more like the latter, because otherwise the system is just a photonic drive, which we already know works.

[lajoswinkler]

I need the latest unbiased news about this. Is it a failure as I thought? Short and sweet, please.

[TheGatesofLogic]

The general consensus is "We're not entirely sure if it works, needs more testing in more environments." and also "we're not sure how it would work if it does, needs more testing in more environments."

[Jesrad]

I need the latest unbiased news about this. Is it a failure as I thought? Short and sweet, please.

The people who have actually gone and tried it are perplexed and report there is thrust. Other people don't count.

[Sky_walker]

Microwaves do not heat the air, they heat the metal of the cavities.

Microwaves heat water. Air does contain water vapor. (not that it matters much)

I need the latest unbiased news about this. Is it a failure as I thought? Short and sweet, please.

It's uncertain for sure, but most likely: doesn't.

There are 2 experiments which get results an order of magnitude different from each other and none of them was performed in anything I would call "optimal testing conditions". As far as I'm concerned - NASA experiment was just a waste of money and time. Pretty much just like Chinese one, though TBH: I expect better from NASA than Chinese. (They got political motives, pretty much just like North Korea had political motives to discover an Unicorn lair)

Edited August 30, 2014 by Sky_walker

[Guest]

The general consensus is "We're not entirely sure if it works, needs more testing in more environments." and also "we're not sure how it would work if it does, needs more testing in more environments."

Translation: It doesn't seem to work, but we could have more data. Now give us more grants so we can gather it. That said, it might work afterall...

[lajoswinkler]

That's what I thought. Thanks.

[Z-Man]

Microwaves heat water. Air does contain water vapor. (not that it matters much)

True. And of course, they're also absorbed a tiny bit by air itself. However, there is very little air and water in there and quite a lot of metal, and the air just has to let things through, the metal needs to reflect the waves. I should have said that the direct heating was negligible.