from the er-that-can't-be-right-can-it? dept.
For many decades, a fantasy among space enthusiasts has been to invent a device that produces a net thrust in one direction, without any need for reaction mass. Of course, a reaction-less space drive of this type is impossible. Or is it ? By Charles Platt
In October of this year, at the laboratory of Dr. James Woodward in California State University at Fullerton (above), I watched a very small-scale experiment that was surprisingly persuasive. Unlike all the "free energy" scams that you see online, Woodward's device does not violate basic physical laws (it does not produce more energy than it consumes, and does not violate Newton's third law). Nor is Woodward withholding any information about his methods. He has written a book, published by Springer, that explains in relentless detail exactly how his equipment works--assuming that it does, indeed, work. He published his theory in Foundations of Physics Letters, vol. 3, no. 5, 1990, and he even managed to get a US patent -- number 5,280,864, issued January 25, 1994.
http://boingboing.net/2014/11/24/the-quest-for-a-reactionless-s.html
(Score: 2) by VLM on Tuesday November 25 2014, @05:12PM
A common mistake elsewhere is confusing this particular drive with a zillion competitors as seen at
http://en.wikipedia.org/wiki/Reactionless_drive#Modern_approaches [wikipedia.org]
There isn't "THE reactionless drive" just like there isn't "THE steam engine"
This particular variant seems to have good theoretical background and a lot of trouble figuring out how to experimentally prove.
The EM drive has pretty fuzzy theory and the experiment is suspiciously "microwave RF gear is cool".
There are a few variants on the theme of "squirt out EM radiation this direction" (light, RF) and those are not even remotely controversial although so low power that they're probably useless for all purposes including even long term attitude control.
And finally there's cheating, not reactionless, but doesn't use propellant, like solar sails and space elevators and slingshot maneuvers and the like. There's a reaction, its just free or someone else pays for it, but superficially it doesn't use propellant so it "must" be reactionless.
(Score: 1) by ScriptCat on Tuesday November 25 2014, @05:46PM
What TFA seems to say, is that the oscillating capacitor in the experiment would change its mass throughout its cycle. This is then connected to an actuator which should push and pull on this capacitor at different points of the hypothesized mass oscillation. But it seems to me like something that would get cancelled out parasitically by other elements of the system if the whole thing is in isolation.
(Score: 2, Informative) by Anonymous Coward on Tuesday November 25 2014, @06:35PM
I mostly agree.
It is useful to keep in mind however that the usual criticism of all these mass-shifting engines, that the shifts cancel out and no thrust can be generated, isn't strictly correct but an approximation. Oscillating masses do theoretically generate thrust in a non-constant gravitational field, i.e. any real field, but it's so low you can't do anything with it. The reaction mass in this case is the planet/star/whatever generating the field.
Kinda pointless if you can't even match aerodynamic drag in LEO.
(Score: 1) by ScriptCat on Tuesday November 25 2014, @08:34PM
Was wondering is that thrust in the direction of the gravitational field :)
(Score: 1) by ScriptCat on Tuesday November 25 2014, @05:18PM
So... Why doesn't this work? And how Quacktastic is it?
(Score: 4, Funny) by dyingtolive on Tuesday November 25 2014, @06:12PM
Lets hope it does. Whenever I encounter other people's children, my first instinct is to try to find some means of propelling them into space. From the headline, it looks like this gives me what I want.
Don't blame me, I voted for moose wang!
(Score: 2) by arslan on Tuesday November 25 2014, @11:36PM
You know after the first x amount of people you meet that you want to send them to space, its probably more efficient to send yourself up there... it'll definitely solve your problem of encountering people with children :)
(Score: 2) by dyingtolive on Wednesday November 26 2014, @12:56AM
Hmm. On one hand, I'm kind of fat, which means that I could send up more kids for my own weight, but on the other hand, annoying American kids are fat too, probably more than me, which would likely result in fewer kids per my own weight..
Don't blame me, I voted for moose wang!
(Score: 4, Interesting) by gman003 on Tuesday November 25 2014, @06:47PM
The theoretical basis seems sound, or at least not blatantly bullshit, but I'm very doubtful it will ever be practical. It's orders of magnitude weaker than even ion drives, which so far are usable only in very limited situations due to their low thrust.
I'm reminded of the Manhattan Project. There, a major problem was figuring out how to isolate the fissile isotopes of uranium from the inert. Because of the war and the accompanying blank-check budget, they tried almost every idea they had. There was one that involved shooting uranium atom-by-atom through a magnetic field, which would perfectly give you the different isotopes. In theory, it was the best method, giving perfectly pure isotopes, and the theory behind it was sound. But it was so slow that it was abandoned in favor of gas centrifuges, which on paper looked like a horribly inefficient way. But they worked better at scale, and so that's how everyone now enriches uranium.
Likewise here. Sure, an essentially infinite amount of dV is cool. Doesn't really help much if you don't even get enough thrust for station-keeping.
(Score: 0) by Anonymous Coward on Wednesday November 26 2014, @03:01AM
While calutrons work poorly compared to uranium hexafluoride centrifuges, it's easier to build a calutrons that works at least a little bit, compared to building a centrifuge.
The refining of the uranium for the hiroshima bomb consumed ten percent of the electricity supply of the entire united states. To make the magnets more efficient, the manhattan project "borrowed" all the silver from the US mint, drew it into wire, then returned it after the war.
(Score: 2) by Kromagv0 on Wednesday November 26 2014, @01:54PM
My understanding was that the reason silver was used in the magnets was that copper was a war material in short supply needed elsewhere so that is why the silver was borrowed from the US Treasury [wikipedia.org].
T-Shirts and bumper stickers [zazzle.com] to offend someone
(Score: 3, Interesting) by physicsmajor on Tuesday November 25 2014, @06:55PM
It actually sounds like it does work. The theory has stood the test of time, the force is measurable and it's reproducible. See my comment below [soylentnews.org] for additional thoughts on the theory. It seems sound.
We're talking about a vanishingly small amount of force, though. It has implications for satellites, e.g., orbital station-keeping, but at least in this form isn't likely to escape any gravity wells. However, eliminating any reaction mass from a spacecraft has huge implications for the rocket equation.
The full equations/theory explaining the effect observed are not yet known, so it might be able to be scaled up or down into the nanotech range in order to greatly increase efficiency. Even so, proof of concept is essentially shown.
(Score: 1) by LAngeOliver on Tuesday November 25 2014, @05:20PM
I think these guys should meet:
http://science.howstuffworks.com/electromagnetic-propulsion1.htm [howstuffworks.com]
Decode your health [biogeniq.ca]
(Score: 4, Informative) by CRCulver on Tuesday November 25 2014, @05:29PM
I'm not sure that means anything. Springer prints all kinds of things, usually requiring authors to provide a print-ready PDF, around which they slap a copyright page and a cover without any editorial intervention. Do they even do peer review for monographs any more? Springer journals have published hoaxes [nature.com] before, which the publisher later had to retract with a red face.
(Score: 2) by hubie on Tuesday November 25 2014, @08:31PM
The book is actually a general science book [springer.com] titled Making Starships and Stargates: The Science of Interstellar Transport and Absurdly Benign Wormholes, so apart from the validity or practicality of the issue at hand, the book didn't need to clear any peer review hurdles. This is good for the author, because if it had ended up being one of the Springer Yellow Books, it would cost way too much for anyone to want to purchase it.
(Score: 2, Informative) by PiMuNu on Tuesday November 25 2014, @05:49PM
Ignore this, it is quackery.
It violates conservation of momentum as there is no externally ejected stuff. I was expecting some light to be ejected, but not even that. There is some relativistic mumbo-jumbo, but this is not even worth thinking about unless the object permanently changes mass, which would require some radiocative decay or equivalent process.
Conservation of momentum can be shown to be a consequence of homogeneity of the universe (laws of physics are the same everywhere).
(Score: 3, Informative) by physicsmajor on Tuesday November 25 2014, @06:23PM
You are wrong, this should not so easily be dismissed. Your understanding of physics is limited, and furthermore I suspect you haven't bothered to open the article. As a quick review lesson, recall the equation for momentum: p = m*v.
If you treat mass as an absolute, invariant constant then you'd be right, the traditional "must eject stuff" is valid. We know momentum is conserved, and if we can't change mass then the only thing left is velocity, which requires a particle with mass (or mass equivalent, for EM waves) attached to it. Ergo, we leave a trail of stuff going in the other direction.
The entire point of this work is that we have missed an important fact; the mass of an oscillating component actually can vary, which you'd know if you had read the article. If you carefully control the situation, using a fast charging/discharging capacitor you can literally shunt a small amount of mass to and from a physically moving component. If you time these transitions correctly, the result is net motion without violating conservation of momentum. Or, rather, the supposed "violation" of (global) momentum is handled locally by the rapid transition of mass in the form of electrons between components.
Your criticism is better levied against the supposed massless EM thruster, but that is different tech entirely.
(Score: 5, Informative) by VLM on Tuesday November 25 2014, @07:02PM
using a fast charging/discharging capacitor you can literally shunt a small amount of mass to and from a physically moving component
In my infinite spare time it would be interesting to ram thru some geometries in an antenna/RF analysis program, if blueprints and specs are ever released. In my infinite spare time (aka never) He may have built the worlds least efficient 40 KHz (or whatever) transmitting antenna, making it basically a EM thruster. Now you won't get a very efficient KHz range antenna in something 3 inches across, but he's not exactly claiming high forces either, so it doesn't sound completely ridiculous. Also whatever RF wave is emitted generating a force however small would need to be considered in the math. Good luck shoving a non-constant current thru a conductor any time without some radiating, however incredibly inefficiently, although when you're talking about low enough level of thrust maybe that's a good enough answer. So a piconewton of mechanical force that-away and a piconewton of EM wave force opposing it, net zilch.
Another thought experiment is mass and energy equivalence, if you're trying to move mass around in a circle / periodic cycle, you can't pretend that just cause its in a conductive wire it doesn't represent energy/mass anymore. So the argument, if not considered very carefully, can also turn into the old "gyroscopes make a reactionless thruster" scam, just with mass converting to energy in a circle instead of old fashioned mass spinning in a circle. Here be dragons when you consider a component in isolation or perfect non-radiating conductors or spherical cows.
Doing this at microwave freqs with pulses and waveguides instead of wires appears to be a degenerate version of idea #2 above. I can make a resonator mass a a bazzilionth of a gram more quite easily, and by doing stupid klystron games (those tubes are probably before your time, although they are kinda cool...) I could make a rather substantial pulse of mass rotate thru various resonators, but this all smacks of the gyroscopic thruster arguments of decades ago.
Other thought experiments involve putting two opposing thrusters on a crank and spinning them, if the force truly is constant you'll eventually have an overunity machine after the crank machine spins up enough. The machine(s) could have "issues" such that overunity is impossible or rephrased being an overunity machine doesn't prevent it from being possible.
I would also be interested in a combination of arguments 1 and 2 above.
(Score: 2) by physicsmajor on Tuesday November 25 2014, @08:08PM
Now here are some valid points!
Without more info I can't address most of your comments, VLM, save one: I don't think there is risk of an overunity machine. Since there is by definition energy loss in the system from the oscillating pulse, and the forces implicated here are incredibly small, I don't think any gain over unity would ever occur.
(Score: 1) by PiMuNu on Wednesday November 26 2014, @04:46AM
> and by doing stupid klystron games (those tubes are probably before your time, although they are kinda cool...)
STFU old timer, we have a few MW klystrons in the basement.
> He may have built the worlds least efficient 40 KHz (or whatever) transmitting antenna, making it basically a EM thruster
He may have done, but the article was saying some nonsense about mass changing during oscillations and nothing about EM. So either the article was wrong or he is a quack.
(Score: 1) by khallow on Wednesday November 26 2014, @05:10AM
(Score: 2) by metamonkey on Tuesday November 25 2014, @07:49PM
I guess what I don't understand is why does vibrating a capacitor that you rapidly charge and discharge change its inertial mass?
Okay 3, 2, 1, let's jam.
(Score: 2) by frojack on Tuesday November 25 2014, @08:45PM
And why does it vibrate? Where does that come from?
No, you are mistaken. I've always had this sig.
(Score: 2) by quitte on Tuesday November 25 2014, @10:41PM
http://en.wikipedia.org/wiki/Mass%E2%80%93energy_equivalence [wikipedia.org]
(Score: 2) by quitte on Tuesday November 25 2014, @11:09PM
after some pondering: if mass and energy is equivalent accelerating energy will create a pulse,too. So the moving of energy around in the sysrem will cancel all the net acceleration gained by exploiting the mass change.
(Score: 2) by Immerman on Wednesday November 26 2014, @02:17AM
That would seem to be a safe assumption, but it presumes that there is a mechanism by which the transfer of energy alone can create a net force to accelerate the system. And when I look at a pair of cables carrying energy between one capacitor and another I'm just not seeing it - the electric field and electron flow is equal and opposite in the two conductors. And everything else could be aligned in any direction, so can't be the source of a force which must generate a displacement along the exact same line as the mass transference is occurring.
(Score: 2) by FatPhil on Tuesday November 25 2014, @06:52PM
And I want to know how producing the same force as a gnat's fart at a distance of several feet from kilovolt electric currents can be considered the future of any transportation. Surely just getting gnats to point their gnat arses in the appropriate direction would be more effective?
Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
(Score: 1) by dltaylor on Tuesday November 25 2014, @05:57PM
Remember, please, that Mach's conclusions predate concepts such as the "quantum foam", along with the rest of a century's work on quantum effects. There is no such thing as a single-object universe around here. If nothing else, the inherent energy of this universe has an equivalent mass.
There's also the issue of scale. While I can vary the total mass-energy of an object by varying charge or temperature, the change is very small compared to the "rest mass" (so to speak) of the object, so the resulting propulsive effect is also going to be very small.
SciFi "reactionless drives" usually involve applying some kind of force against space itself. Perhaps a directed Higgs field?
(Score: 2) by physicsmajor on Tuesday November 25 2014, @06:47PM
Remember, please, that gravity and mass itself is what we have failed to reconcile with quantum theory despite decades of efforts. Waving a hand at this stuff is not a counter argument. I don't see any reason why this method would be dependent on quantum foam or other quantum effects. I'd encourage you to actually read the article.
Scale is a valid criticism of the applicability of the technology. It's not, however, a correct way to go about evaluating validity. The effect observed is small, but it is measurable and reproducible.
Once you're in space, if you move from generating power alone (RTG, solar, or otherwise) that has huge implications because you can eliminate some of the otherwise necessary reaction mass.
(Score: 1) by dltaylor on Tuesday November 25 2014, @08:52PM
I DID read the article (hence the reference to Mach). Although we commonly link mass and gravity, this proposed effect does not. It relies, apparently, purely on changing mass-energy. While it would be interesting if the theory is correct, it seems much more likely that something else is happening.
I do wonder about conservation of momentum. If the enclosed system (spacecraft) accelerates, it is gaining momentum. Somewhere, at some level, something else must be gaining momentum in the opposite direction. In the lab, that something else could be any, or all, of the lab equipment, or, for that matter, the planet.
(Score: 2) by maxwell demon on Tuesday November 25 2014, @07:30PM
If you reduce the charge of the capacitor, you have to move the energy somewhere (because we still have energy conservation). And whatever you store it in will get the "missing" mass. And if you are in a satellite, it will also be part of the satellite. Not to forget the momentum of the current/field flow. And if you add up the numbers, the net effect will certainly be no thrust (except for any radiation leaving the system; that of course may cause thrust, but for that it will be more effective to explicitly generate it).
Putting only part of the complete system (capacitor + energy source) on your scales doesn't prove anything about usability for a thruster. I can use an ordinary water pump to pump water into and out of a tank. If I put the tank on scales, I'll see massive mass variations. But that doesn't mean I could use my water pumping system to generate thrust.
The Tao of math: The numbers you can count are not the real numbers.
(Score: 2) by Immerman on Tuesday November 25 2014, @07:58PM
Actually I think energy conservation is not really an issue: If you take their "cranked railcars" example, you're oscillating mass between car A and car B. Push them apart while car A is heavier and pull them together while car A is lighter, and you get a net motion towards car B. If car B's mass is oscillating in counterpoint it only makes the effect more dramatic.
The problem that I see, which I think is the same you're getting at, is that he seems to be assuming that mass can be transfered between A and B without altering their momentum. The complete closed system would have to be measured to ensure that the momentum changes of flowing energy doesn't perfectly counteract the momentum changes of oscillating masses. It may well be that the torque of his thruster is balanced by an equal-but-opposite torque on his power supply. Of course I'd be really interested in knowing how a torque could be conveyed by electrons flowing along an axial cable, that could open up whole new realms of physics potentially even more mind-bending than "reactionless" thrusters.
(Score: 2) by frojack on Tuesday November 25 2014, @08:54PM
The problem that I see, which I think is the same you're getting at, is that he seems to be assuming that mass can be transfered between A and B without altering their momentum.
Exactly. Which is why that topic got dropped just as quickly as it was introduced. The point it was trying to
make was going nowhere fast.
Actually the example never addressed a change in mass of B. Only of A. And it left unsaid where this mass was going. If the whole apparatus were contained in a space ship, the mass deleted from A would still be in the ship, and as you move said mass to the new location of A, for the next cycle, you zero out any gain in momentum of the ship.
No, you are mistaken. I've always had this sig.
(Score: 2) by Immerman on Wednesday November 26 2014, @01:51AM
The example doesn't need to address a change in mass of B - assuming mass is transfered back and forth between the two cars only amplifies the effect. The question is only whether that mass can be transfered without generating a corresponding displacement. That seems to me an awful big "if", but I can't think of any obvious mechanism that would allow a closed-loop flow of electrons between the two mass-energy reservoirs to alter momentum. It's not like we're tossing bowling balls from one end of the ship to the other: The red and black wires should see an equal-but-opposite electric field and electron flow at all times, perfectly negating any electron/conductor interactions as a source of momentum transfer. You may move energy from Capacitor A to Capacitor B, but there has been no net flow of electrons.
Now, my first assumption would be that I'm simply exposing my ignorance or oversight, but if the stored mass-energy really does "evaporate" from one capacitor and "condense" in the other without imparting a net physical force on the circuitry, then the rail cars / space ship should work exactly as described, with every cycle generating a slight net displacement.
(Score: 2) by frojack on Thursday November 27 2014, @09:15PM
You are mixing a kinetic energy model with an electric energy model.
But that wasn't what was postulated, and no mention of transfer of any mass or electrical energy existed in the model. It was strictly an unworkable kinetic energy model with a reduction of mass in one side allowing initial to choose which side moves.
You can play that game until there is no more mass located at A. Then its game over.
Passing electrons, especially bidirectionally, won't help you.
No, you are mistaken. I've always had this sig.
(Score: 2) by Immerman on Friday November 28 2014, @09:36AM
Re-read the example, I'm pretty sure they are cycling the mass of A. A gets pushed away, then becomes lighter, then gets pulled close, then becomes heavier, then gets pushed away, then becomes lighter...
Oh, wait, no, they didn't explicitly list the "becomes heavier" stage. But I think that's implied by the return to the initial mechanical configuration and the fact that they're explicitly discussing oscillating systems. And once you're back to the initial conditions (slightly shifted) you can repeat the cycle for as long as you can power it, and those two little cars will go cruising down the tracks in jerky little inchworm motions.
And no, in that example they didn't mention any implementation details at all - it's an introductory conceptual model, and only focused on the mechanism by which "magic" mass changes could allow you to move without reaction forces. The rest of the article discussed the implementation details.
And yes, I then hybridized the conceptual model with the article details as to how mass changes are accomplished by moving stored energy with the conceptual model, but I did so in what I would consider a perfectly legitimate manner: if the theory is sound and the cars don't move when you're just transferring energy between them then the machine I described should in fact work. And if you weld one car to the tracks they'll drag the tracks, and the rest of the planet, along with them. Or a space-ship, if you want more readily measurable degree of motion.
As for shunting the energy back and forth between cars, that might be my own addition. It makes sense though - if you want to do this on a large scale you need a lot of mass variation, which means a *LOT* of energy, and you don't want to have to generate all that energy with every cycle. Especially not in space with limited energy reserves. So instead you shunt it back and forth between cars, and as a side effect amplify the effect by having B's mass oscillate in counterpoint to A.
And on a crude level that describes how this engine would work in practice: the piezoelectric resonator plays the part of the mechanical crank, the vibrating capacitor plays the part of car A, and the rest of the ship plays the part of car B.
(Score: 1) by EETech1 on Wednesday November 26 2014, @04:12AM
scienceblogs.com/startswithabang/2009/04/10/the-left-hand-rule/
How electrical current puts a torque in a cable
hmmmm
(Score: 2) by Immerman on Wednesday November 26 2014, @05:35PM
But it doesn't - it generates a magnetic field, which *would* potentially exert a force on the surrounding apparatus, except that there's a parallel cable running alongside it to complete the circuit, and that cable is generating an exactly equal-but-opposite magnetic field, canceling the effect out.
(Score: 1) by qwerty on Tuesday November 25 2014, @08:23PM
I can't scroll past the first unapologetic photograph of his office laboratory in the linked article. It's what I assumed my basement would look by now were I pursuing a Nobel prize in something. This is especially true of the donut box at the epicenter. *This* is what real science looks like, people! I know what I'm doing this Thanksgiving long weekend ...
(Score: 2) by turgid on Tuesday November 25 2014, @08:33PM
Ah, how exciting if true, and the man has a PhD!
Plenty of flowery waffle for the non-technical intended audience, until we get to this:
Mach concluded that inertial mass only exists because the universe contains multiple objects. When a gyroscope is spinning, it resists being pushed around because it is interacting with the Earth, the stars, and distant galaxies. If those objects didn't exist, the gyroscope would have no inertia.
Wrong. A gyroscope is in an accelerating reference frame (velocity - the vector - is constantly changing). It is not an inertial reference frame.
Then we go on to the old capacitor charge/discharge chestnut. Every few years these crop up and there's always a problem. Most fundamentally, the person proposing the mechanism always overlooks the finite speed of light and therefore the finite speed of the other forces, including electrostatic repulsion/attraction and the speed of light.
Who remembers Shawyer and his rotating truncated cone EM cavity resonator? It moved all right, but that was more to do with heating air about an asymmetrical body to produce a thrust.
Sorry, you're still going to have to conserve momentum. Now, that could be throwing mass out the back of your spacecraft, or maybe even photons. After all, photons have momentum :-)
I refuse to engage in a battle of wits with an unarmed opponent [wikipedia.org].
(Score: 0) by Anonymous Coward on Tuesday November 25 2014, @09:21PM
The EM drive didn't produce thrust due to convection currents, the thrust appeared the moment current was supplied. The systems used would need several seconds to warm up to the point where this became a measurable factor.
(Score: 2) by turgid on Tuesday November 25 2014, @09:27PM
Funny how it didn't work in a vacuum.
I refuse to engage in a battle of wits with an unarmed opponent [wikipedia.org].
(Score: 0) by Anonymous Coward on Tuesday November 25 2014, @10:48PM
Source?
(Score: 0) by Anonymous Coward on Wednesday November 26 2014, @02:21AM
IIRC, they tested it in a vacuum chamber... but didn't evacuate it.
Really, extraordinary claims require extraordinary evidence. This is complete BS.
(Score: 1) by khallow on Wednesday November 26 2014, @05:24AM
Then we go on to the old capacitor charge/discharge chestnut.
What's the problem with this assertion? We can charge capacitors. We can minutely change the mass of a capacitor by charging and discharging it. If you charge a capacitor and exert force in one direction, then discharge it and exert a slightly weaker force to return the slightly less massive capacitor to its initial position, then there has been a net force in the system from the point of view of the capacitor. There's no need to worry about the speed of light here. It is irrelevant.
But what is relevant is that you are moving energy through the system electrically and that might exert forces on the system as well.
Sorry, you're still going to have to conserve momentum. Now, that could be throwing mass out the back of your spacecraft, or maybe even photons. After all, photons have momentum :-)
Or the rest of the universe might be the reaction mass. In which case, the modelers would need to explain how the thruster is coupled to the rest of the universe. That is a weak point of the theory right now.
(Score: 0) by Anonymous Coward on Tuesday November 25 2014, @09:48PM
I don't care how many laws of physics it appears to violate - show me a working prototype.
To the detractors out there: if you aren't funding development, why do you care if it seems impossible to you? Do you have a better idea that is competing for his funding?
(Score: 2) by hubie on Tuesday November 25 2014, @10:23PM
It is hard to be a scientist and simply ignore impossible claims, even if they only seem impossible to you. What makes one a good scientist is constantly questioning the unexplained, or if it is only a matter that you don't understand but everyone else does, then you keep questioning until it makes sense to you.
(Score: 2, Interesting) by steveha on Wednesday November 26 2014, @12:49AM
Did you read TFA? He has a working prototype.
The demo was: Put prototype into a sealed plastic tube. Pump tube down to a vacuum. Apply electricity to prototype. Result: A very small net thrust is measured.
Let air back in to the tube and open it. Put prototype in to the tube with direction reversed. Pump down to a vacuum (during this time they went to lunch). Apply electricity to prototype. Result: a very small net thrust is measured, this time in the reverse direction from the first demo.
Whenever I read something like this, my first two thoughts are "is it pushing on air" and "is it pushing on a magnetic field". This would seem to rule those out, assuming that the trials were faithfully done and competently done.
It would be cool if this pans out, but I don't express an opinion on how likely it is. But at least one can't say "he doesn't have a prototype".
(Score: 1) by ScriptCat on Wednesday November 26 2014, @08:04PM
Apply power, It's pushing on the power supply.