The article's 3 years old, but there's apparently been some new developments in the past few months. More at the link. Website of the UK company working on the drive with links to abstracts to recent Chinese papers on the subject.
I should have added 'to people other than the Chinese'. Im not saying I think its impossible, I just think it's the kind of thing that should come up more theoretically before it gets stuck on a rocket. Like the Ion Drive
I always refer to my Heinlein when these sorts of arguments crop up: "Always listen to the experts- they'll tell you what's impossible. Then do it anyway."
You can't get around basic science by quoting Heinlein. Shawyer proposes a machine that doesn't emit anything, yet produces thrust. That's like pulling yourself up by your bootstraps. Using electric energy to generate thrust is not impossible: an ion drive does just that. However, an ion drive emits ions and doesn't violate basic scientific principles. Shawyer first proposed his drive in 2002. One would except that in nine years, someone other than him must have been able to at least reproduce his findings. Of course there's a reason why no one has been able to confirm what Shawyer says: the law of conservation of momentum does not allow reactionless thrust in this universe.
I'm highly skeptical. Just a couple of points: 1. Something revolutionary could appear to be nonsensical at first look. No one was comfortable with the idea of time being relative to the motion of the observer, either. 2. The Chinese are only as smart (and as gullible) as anyone else. That (unnamed) researchers have confirmed the effect and are trying to produce a model is interesting, but there were people trying (and, apparently, still trying) to make cold fusion work. 3. At the end of the day, propulsion works by causing an action, and pushing the vehicle along by the simultaneous reaction (thank Newton for that little gem). Electromagnetic energy can be thought of as photons emitted from a source, so, I'm sure it's possible that if one could blast sufficient photons out the back of an engine, thrust would be developed. But you'd need a LOT of photons. There's a reason we throw screaming hot molecules of gas out of rocket nozzles---it's fairly easy to produce get a large action from them...
The technical background on Shawyer's website is interesting. Clearly, this guy has a strong background in RF engineering; much of what I could follow is accurate. Usually, when I read a hoax, I don't get very far into it before the writer introduces something that destroys all credibility (like, assuming some hitherto undiscovered force of nature). Central to the guy's thesis is that a relativistic effect results in there being a differential radiation pressure--and therefore a resulting thrust--on the two ends of this truncated conical container. That's where this thing has to fall apart. If photons are emitted inside this nacelle (as they must be), and equal numbers of them travel to hit both the front and back surfaces, then, from the point of view of someone inside the nacelle, they have to maintain their same energy/wavelength. I don't see how a difference can develop. It's a complicated subject, and maybe I'm ignorant of some important detail, but I think this is probably hooey.
I don't think its a 'hoax' in the normal sense, I think Roger Shawyer does actually believe in it, and he does know a lot about relativistic physics. Given the amount of other experts at his level or higher who have looked at this and said noooo, it looks like he might just be wrong.
Shouldn't this be a simple matter of building the damned thing and seeing if it flies? I'm sure it'll nuke a mean hot pocket even if it doesn't work as an engine.
False claims of revoluationary engines / drives / powersources generally are one of two types: 1: An outright hoax. The person knows its bullshit from the outset but runs as far as he can with it and dupes as many gullible / scientifically ignorant people as possible. Either as a scam for monetary gain, or simply for teh lulz. 2: Delusion of discovery: The person thinks they really have come up with a revolutionary device. Unfortunately their science is off and it won't actually work. I'm thinking this falls into category 2.
Well I'm no scientist but I'm with UA. Build the damn thing and fire it up. See what happens. Probably nothing of course since it flies in the face of everything we know. For all we know it shoots out particles we haven't detected yet. I wonder how the Chinese bought into it. But seriously I don't think it will work.
From wiki so take it with a grain of salt..... With a grant from the UK government's Department of Trade and Industry of £250,000, (actually two grants; one a feasibility study of £45,000 and a second of £81,000 to build a demonstration engine - source SPR Ltd.) a commercial regulatory and support agency,[8] Shawyer has built two prototypes that reportedly produce 16 mN and 300 mN of thrust respectively; each using 1 kW of electrical power. A condition of the funding was independent analysis, which was recently completed by John Spiller who says "The thruster's design is practical and could be adapted fairly easily to work in outer space". Shawyer claims that he has been visited by representatives from China and the US Air Force, but ESA has not yet shown much interest. He estimates that his design could save the aerospace community $15 billion over the next ten years. Engineers in Germany have created superconducting resonators (for use in particle accelerators) with Q values of several billion, which Shawyer claims would equate to a thrust of 30 kN per kilowatt, "enough to lift a large car". Shawyer states that the thrusters work best while stationary relative to their thrust. http://en.wikipedia.org/wiki/EmDrive
If real, that's a pretty good beginning. 300mN isn't a lot of thrust, but if Shawyer's theory is correct, much higher thrusts are possible with increasing circuit Q. This information isn't attributed in the Wiki article, so no independent verification. However, there is a "flight video" (a video purporting to show the engine operating) at this link: Eureka Magazine link: EMDrive Not independently verifiable. If so, this would change the world. A vehicle with a mass of 1000kg (about a ton) would have a weight of about 10kN (1000kg * 9.8m/s^2). If an engine like this could produce 30kN of thrust, the vehicle could be lifted with 20kN of force (30kN - 10kN). For a 1000kg vehicle, that means an acceleration rate of 20000N/1000kg = 20m/s^2. In other words, the vehicle would accelerate upwards at around two-thirds of a g! 1 kilowatt of energy ain't much...about 1.3 horsepower. This could make things like flying cars very practical. If it's true.
Paladin, when you bust out an analysis like that in a WF post it just shames me- makes me realize how stale my AE degree actually is. These days it would take me a good while to sit down and crunch that all out if I was even arsed to do it at all. Kudos!
Sadly I don't think it's true. I wish it to be but it seems everything "cool" never works out in the end. Every scientist in the world would have to fly to this guys house, get on their knees and kiss his ass for an apology if it were true.
