Talk-Polywell.org

TDPerk wrote:Plasma has much lower mass, but can have much higher frequency, correct?

I dunno. I think you want a plasma physicist to know. Plasma confinement would seem to me to be limited by coulomb forces, and I would suppose the density can approach that of other states of matter, but you'd need to look at the densities different folks have generated. The crazy UFO story on the web about the TR-3B Alien Replication Vehicle is that the Mercury is pressurized to 250,000 atmospheres. I have no idea if that is possible, nor what density it would give, but certainly if you were going to toy with an Hg plasma design, you'd want to ask these questions. Let me note again, I am not endorsing these kinds of stories as I find it very long odds there is any truth to them.

I don't see why you pass anything through the slip rings but DC.

The device needs to be driven by a 1w+2w AC signal, and perhaps pulsed AC as with Woodward's most recent patent app. The higher the frequency the better. One advantage to using plasma is you are no longer limited by the acoustic velocity of a solid, to work with whatever frequency for whatever thickness. So you want to use the highest frequency you can--millimeter wave would be a nice choice if you have those resources. If not you can put up with the crappy waveforms from a standing wave magnetron for a couple hundred bucks, and by using two of them, you can hope to get your 1w+2w and be able to control the phase between the components. Certainly though, you don't want to put all this power gear on the thrust measurement arm without a reason so you're likely better off passing AC than DC, Depends how much you can shrink the power system though. I can tell you even miniaturized, it appears the power system for a UHF MET will greatly outmass the thruster it powers (2-3 orders magnitude), so the power system mass is very important to consider. You would not put it on a balance arm unless forced by other concerns (like impedance matching requirements) to do so.

-snip-

I think you want to post that in the EM Drive thread.

GIThruster wrote:The device needs to be driven by a 1w+2w AC signal,

Of course, but if I wasn't mistaken you're talking about doing this in a centrifuge. Seems like you'd want to generate the feeds in the rotating machinery as locally as possible to the load, and feed it from sliprings of liquid metal.

Liquid metal slip rings cannot be used for high speed. If you look at the design of slip rings available, liquid metal is reserved for low rpm.

The details of how this sort of thing could be accomplished are pretty complex. It is the measurement apparatus and the mass it can handle, that really determines what you can do. If for example, you suspend the entire thruster like a pendulum and hang a laser off it and read the changes in the laser's position 30' across the room, you can get pretty high mass and low thrust measurements, but then you're limited as to what kind of power you can hang. You might be forced to use batteries and have to hang the entire power system. That is a LOT of mass. Might well be too much for even an accurate pendulum.

Woodward passes his power through his balance instead of going self-contained on the balance arm for very good reasons. Whenever you do an experiment like this, you have to be able to provide the scientific controls that make the experiment worth doing. So for example, you need to be able to vary power in. Providing the proper controls to a wireless system you have no physical connection to is very expensive, and in most instances would be a deal breaker. Note even Eagleworks does not have that sort of setup. It would be millions just for the power system.

"Liquid metal slip rings cannot be used for high speed. If you look at the design of slip rings available, liquid metal is reserved for low rpm."

I think I see where you are allowing yourself to be stopped from proceeding in this direction.

Well I think working with plasma is a little beyond my scope. We don't know that much about it and there is lots of room for improvement with the MET as is. I already have a basic UHF design that I want to pursue commercially.

But in general, it is always best to respect COTS. People who build high speed slip rings and sell them for thousands of dollars a piece, generally know things other people do not about slip rings! It's important to have some humility in this respect. I find very often engineers and other smart, handy guys, want to innovate where it is not necessary, and what they don't understand is, they could spend months or years on a project, fighting with something that they could have purchase off the shelf.

This is in fact one of my main complaints about Woodward's work in the past. He innovates where he doesn't need to. There was for instance, no reason for him to build the thruster itself. He could have purchased a handful of Langevin transducers off EBay, inserted accelerometers, and matched the power system to them, but he didn't. When he spends weeks at a time assembling transducers in a jig, it is all wasted time, IMHO. Likewise with displacement actuators. He should have simply bought COTS actuators with the casings and springs, and run them with what he had, and he refused. When you look at the volume of work he's accomplished over the years it's pretty fantastical, but it is a tiny fraction what he would have accomplished had he had the attitude that one doesn't need to always be reinventing wheels.

somewhat of a cross subject post by Paul March, posted on Nasa SpaceFlight Forums these last days.

interesting tidbit from him:

BTW, IMO Jim Woodward's Mach-Effect (M-E) conjecture that is based primarily on SRT and GRT, is still in the running for a way to explain his and our test results to date. However the M-E also has its detractors since it requires that instantaneous Wheeler/Feynman radiation reaction forces being required between a local time varying mass and all the other mass/energy in the casually connected universe, since this mechanism is used to balance the M-E's energy & momentum conservation books. In the end analysis though I think that the ME will rest on the quantum nature of space-time, since in Woodward's eyes the gravitational field IS space-time, and in our eyes GRT's space-time is in reality the quantum vacuum that probably has at least 4 spatial dimensions and one time dimension!

Best, Paul March

GiThruster,

Found a reference to this paper from a set of folks from ORNL disputing Mach effect theory while reading the EmDrive thread on NSF. Wanted to know if this is an old rebuttal and if so what is the correction. Also, is this the same set of guys that are referred to in the Woodward book that tried to replicate the work but weren't forthcoming with their results?

http://web.ornl.gov/~webworks/cppr/y200 ... 111404.pdf

birchoff, this is an old refutation attempt (more of a misunderstanding actually) back in 2001. This is listed in the Woodward effect article on Wikipedia:

A challenge to the mathematical foundations of Woodward's theory were raised in a paper published by the Oak Ridge National Laboratory in 2001. In the paper, John Whealton noted that the experimental results of Oak Ridge scientists can be explained in terms of force contributions due to time-varying thermal expansion, and stated that a laboratory demonstration produced 100 times the Woodward effect without resorting to non-Newtonian explanations.[REF.1] In response, Woodward published a criticism of Whealton's math and understanding of the physics involved, and built an experiment attempting to demonstrate the flaw.[REF.2]

The first link [REF.1] in the quote above is the one you provided, have a look at [REF.2] which is Woodward's answer.

birchoff wrote:Wanted to know if this is an old rebuttal and if so what is the correction.

To the best of my knowledge, there has not been any new objections since this and this was during Tom Mayhood's Master's Thesis work in the 1990's. It is true Tom failed to clearly demonstrate he was not looking at thermal effects on his suspension pendulum. It was plainly not a good design, hanging the thruster by the power leads. I don't think Woodward more than mentions this work because it is just not up to professional standards. The U-80 and its later iterations were far better than Mayhood's pendulum and the ARC Lite is a vast improvement.

In any event, you have to be able to demonstrate running your thruster at full power and heating up the entire system, to show that your signal is not a heat signature, and Tom couldn't do this at all. The ORNL guys were right to complain about this. However they were entirely wrong to make their more lasting complaints and Mayhood's answer to them was completely definitive. The issue is really closed. Anyone can open it but they need to look at the answers provided.

GIThruster wrote:I already have a basic UHF design that I want to pursue commercially.

On the side, Woodward has a patent, last I heard, right? How much time is left, how much does it cover, and how much would he be asking for license?

I can't discuss business matters here, so all I can say is this is not an issue for us. It may well be for others.

GIThruster wrote:https://www.linkedin.com/pulse/mach-eff ... -ron-stahl

Wow. Interesting read. What was the purpose of writting it?