Mach Effect progress

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GIThruster
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Re: Mach Effect progress

Post by GIThruster »

I'm sorry but, no. They're doing the math wrong. If you want to account for the exhaust in the accelerating frame you'll eventually get round to the same observation I have already shared and that is the origin of the conservation violation objection. It is based upon taking a figure of merit that exists for all thrusters, the thrust efficiency figure; and pretending it is invarient. It is not. The figure is a constant, but when you take these figures for stationary thrust and pretend they teach a dynamical relationship, you are wrong. Not incomplete--wrong. You cannot take the figures from a stationary relationship between variables that are not invarient, and simply use them in another frame of reference, especially a non-inertial frame; and then expect something other than gibberish. And this is precisely the mistake that has been made over and over again by more than a dozen people, so when you appeal to yourself as an authority, you need to recognize that your authority does NOT extend to a working knowledge of how this particular error has popped up again and again over the years.

Calculations that look at exhaust velocity are NOT necessary. All that is necessary is to note that the elements that make up the thrust efficiency figure of merit are not invarient, and cannot be handled in the manner proposed.
"Courage is not just a virtue, but the form of every virtue at the testing point." C. S. Lewis

93143
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Re: Mach Effect progress

Post by 93143 »

When I appeal to myself as an authority, I am speaking specifically of the question of energy accounting in a rocket engine.

I make no claims to understand exactly how a Mach-effect thruster is supposed to work. But I do know how a rocket engine works, and in that context you are the one talking gibberish.

As a philosopher, you probably never studied the energy method for solving problems in mechanics. It can be quite interesting to see how this method can be used as an extreme shortcut in certain types of problems, while still being just as correct as the laborious force-integration method, and to understand why this is.

GIThruster
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Re: Mach Effect progress

Post by GIThruster »

I'm not talking gibberish. I'm telling you what the standard conservation violation argument is based upon. It takes the standard figure of merit, the thrust efficiency figure that is a constant when the thruster is stationary, and pretends that it is a constant when the thruster is accelerating, when it is not.

If you do this with any rocket engine, you will get a seeming violation, identical to the one posted wrongly on wiki which claims:

". . .the kinetic energy would grow as the square of the elapsed time, while the input energy grows linearly with time." It is this conclusion that is WRONG and the conclusion comes from the mistake I have identified for you. No analysis of exhaust gasses is needed to correct this mistake. It is corrected properly by noting that the figure of merit is not invarient. End of story.
"Courage is not just a virtue, but the form of every virtue at the testing point." C. S. Lewis

93143
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Re: Mach Effect progress

Post by 93143 »

It is, though. The power exerted by a rocket engine does not depend on its velocity or acceleration.

Propellant flow and thermal efficiency are basically constant. Heat of combustion is constant. Thrust is basically constant. That constrains the problem.

Or take an electric thruster. Power input, propellant flow rate and relative exhaust velocity are all basically constant. That constrains the problem.

dkfenger
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Re: Mach Effect progress

Post by dkfenger »

The math for energy conservation was laid out quite neatly by a post from chrismb in General: viewtopic.php?f=8&t=4190

Any propellant-based rocket does not violate energy conservation at any speed, once you account for the propellant as well as the rocket. Period.

I like chrismb's more recent analysis of the issue - *if* a ME thruster is truly thrusting against 'the rest of the universe', then its thrust-energy relationship will be dependent on its velocity wrt the rest of the universe. Would figuring out what the actual rest frame is for 'the rest of the universe' count as a privileged frame, from the point of view of the first postulate of special relativity?

93143
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Re: Mach Effect progress

Post by 93143 »

I wasn't all that impressed by chrismb's M-E thruster vs. rest of universe scenario. I thought it was intuitively obvious - it's certainly the first thing that occured to me...

The thing is, I had the impression that these devices were supposed to have velocity- and orientation-independent behaviour. It seems to me that this scenario entails a potential entropy-condition violation - but I'm not willing to declare it impossible on these grounds because (a) people who probably understand it better than I do have suggested that this is not the case; this seems like a situation where some relativistic consideration might come into play, and I don't have the necessary understanding of both relativity and Woodward's work to nail it down, and (b) the purported time-reversed interaction that makes inertial reaction instantaneous sounds like it might just possibly constitute a loophole in the Second Law.

In any case, Woodward's mass fluctuation equation doesn't seem to be dependent on the relative velocity of the "far-off active mass", and the local forcing shouldn't be either, so I don't know where such a dependence would come from... certainly if inertia itself were velocity-dependent, we'd have noticed by now...

On the other hand, Woodward's criticism of the WarpStar-1 trip time calculations seems to imply that it is indeed not quite that simple...

I've ordered the book and will take a closer look when it arrives.

Jded
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Re: Mach Effect progress

Post by Jded »

dkfenger wrote: I like chrismb's more recent analysis of the issue - *if* a ME thruster is truly thrusting against 'the rest of the universe', then its thrust-energy relationship will be dependent on its velocity wrt the rest of the universe. Would figuring out what the actual rest frame is for 'the rest of the universe' count as a privileged frame, from the point of view of the first postulate of special relativity?
Doesn't the "rest of the universe" change with the vehicle's light cone (in connection with velocity)? That would mean no priviledged frame.

I never managed to fuly understand the math behind this, but I've got the hunch that changing light cone (i.e. changing things you're reacting against) with velocity might solve entropy problems. When you finish accelerating, the miniscule effect you impart on the rest of universe will be varied over distance/direction.

On the other hand, if the inertia is dependent on far-off reaction mass, shouldn't it change over time, while the universe is expanding?

93143
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Re: Mach Effect progress

Post by 93143 »

Re: lightcone - the speed of light is the same in all frames, and relativistic foreshortening is symmetric (and small). I don't see a mechanism there, though as I said I'm not an expert on relativity...

dkfenger
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Re: Mach Effect progress

Post by dkfenger »

Jded wrote: Doesn't the "rest of the universe" change with the vehicle's light cone (in connection with velocity)? That would mean no priviledged frame.
Probably. It'd be an interesting problem to poke at if the ME-drive gave us the tools to do so.

However, I'm not particularly worried about it. I'm inclined to believe that the ME drive is just an electronic Dean Drive. If real thrusts are shown in a self-contained unit in vacuum, then it might get interesting. Until then... extraordinary claims require extraordinary evidence.

93143
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Re: Mach Effect progress

Post by 93143 »

I wish people would stop quoting that grossly misleading thought-stopper. Why should the standard of evidence be different for claims people don't find "extraordinary"? Evidence is evidence.

It's not like Woodward is challenging well-established physics here; he's simply exploring a neglected implication of General Relativity.

TDPerk
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Re: Mach Effect progress

Post by TDPerk »

"If real thrusts are shown in a self-contained unit in vacuum, then it might get interesting."

I believe that has already been demonstrated.
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93143
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Re: Mach Effect progress

Post by 93143 »

I don't believe it has, if I recall correctly. The experiment is apparently fairly difficult to set up that way, considering the power supply and instrumentation and so on. Vacuum, yes, and with the thruster in a Faraday cage, but not totally self-contained.

The equipment is supposed to be well shielded, and there have been a variety of experiments performed to try to eliminate spurious thrust effects. At least one experiment series was designed to show the Mach effect without producing net thrust, and it showed a signal in antiphase with electrostriction, as predicted, and scaling as expected. There have also been thrust reversal, thrust elimination, and dummy load tests. And the recent re-derivation of the expected thrust with higher accuracy, while it still makes simplifying assumptions, seems to have resulted in predictions within an order of magnitude of the results.

I am making no claims myself, other than that I don't think it's fair to consider this "not interesting" at this stage.

GIThruster
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Re: Mach Effect progress

Post by GIThruster »

This directly above is correct. All self-contained experiments are on hold until real funding arrives. They are far too expensive to do given the multitude of scientific controls one needs. If someone can find a way to preserve all the abilities Jim has on the balance, and at the same time add the self-contained component, that's great. Just saying though, the engineers involved understand the challenge and have been quite clear, that is an extremely expensive bit of kit. It's going to take a lot more money than one would have access to even with a NIAC grant.

And just noting, the people who press for a self-contained setup always turn out to be the lazy type. They never understand how the experimental setup as exists works, and thus does not require that component. Were they to invest themselves, they would learn it is unnecessary just as anyone who invests himself in understanding the experiment knows that there cannot possiby be a Dean Drive effect going on. This has been ruled out many times.

I would offer this one correction however: ". . .seems to have resulted in predictions within an order of magnitude of the results"

It is not right to use the term "prediction" in this way. Since I have corrected Sonny White on this issue numerous times I would be remiss to fail to note here, the refinement in the derivation that has begun yielding thrust figures did not preceed the thrust data. It is therefore incorrect to say it "predicts" unless someone were to do a new series of tests using different criteria. For instance, were Jim to change the frequency he's working at, it appears he could make his first real prediction and see how close experiment comes. That would be a first. Jim has never made thrust predictions before.

Others claimed they had made predictions and were lying. All these false claims made by others have been completely irresponsible. I would note too that all these supposed predictions made by others have been abused to promote a very different situation than the one that exists. All the supposed "predictions" thus far in M-E work and the QVF work have been pure bullshit, and an insult to what science is all about. They are evidence of pathological science and Jim has never had anything to do with them. He is completely above that sort of nonsense.

And yes, I think people misunderstand what Carl Sagan was saying when they use his words to require a higher standard of evidence. If one is entirely rational, one makes judgements about the evidence in a much more impartial way than is implied by Sagan's pithy grabber. But he was a TV personality, not a philosopher. Cut him some slack.
"Courage is not just a virtue, but the form of every virtue at the testing point." C. S. Lewis

AcesHigh
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Re: Mach Effect progress

Post by AcesHigh »

All self-contained experiments are on hold until real funding arrives.

GIT, can you please clarify on this? Real funding?? I remember sometime ago the talk that Jim Woodward would not accept investors and such. What kind of funding is he getting? How much do you think that will accelerate the whole experimental process? What are the plans regarding what to do with the money, besides the self contained experiments? Better (and more expensive) materials to amplify the mass oscilations? Maybe metamaterials?

GIThruster
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Re: Mach Effect progress

Post by GIThruster »

I'm sorry but I didn't mean to imply that "real funding" is on the way. What I was implying is the contrast between tiny funding such as what is available through NIAC and significant funding.

IIRC, NIAC grants top out at $100k. That's enough to purchase some materials and such, but it won't pay even a single PhD EE for half a year, in order to build a proprietary power system. If we're to see the kind of self-contained power system needed for the experiments people imply they'd be convinced by, we'd need to see a 7-digit investment.

There has been some talk of filing for a NIAC grant to pay for supplies. I don't know if that's going forward. I heard that to get hold of the raw PMN is around $6k and that is without paying for the dies and sintering it into useful form. The dies are another $1k. I know people are now checking on CCTO from China since that could be far cheaper, and I have suggested folks check on LSNO as well, but I have not heard what the outcome is of this.

I know there is a chemical manufacturer in FL that supposedly offers PMN and CCTO, but they have not responded to inquiries at all. Same with Ecertec in the UK--no response from weeks worth of inquiries. Looks like they're out of business.

Just my take on the funding issue, I want to see three things before someone invests millions--higher thrusts, parametric studies that clearly demonstrate scaling and replication. These are all the kinds of things that can be had with small investments. Honestly, if we saw any two of these, we'd likely have someone like L-M step forward and offer to do their own internal study. That would kick the doors open. I think though, the course Jim is on to pay for his own next gen materials with proceeds from the book is a good path to pursue.

To your question as to what to pursue once "real funding" to the tune of millions arrives--I am not aware of any single plan. There are three Captains of Industry involved whom I think know what they would like to accomplish given that sort of funding, and I have my own opinions here, but I think what we'll see is the golden rule: those with the gold make the rules. Basically, those who have control over funding will decide what they want to accomplish with it. We can then all sit back and decide if what they did makes sense to us and our hindsight will make us all feel very clever.

I will just note that IMHO, once real funding arrives, someone needs to jump on microwave thruster development. We need to see LSNO laid down on Bragg mirrors and powered by portable power systems. That needs a couple million at least to tinker with but that is where the future of human spaceflight is, IMHO. Lower frequency iterations are not going to have the thrust efficiency or thrust/weight necessary for human spaceflight. They'll be great for all sorts of satelites and deep space probes, but I think we have bigger fish to fry.
"Courage is not just a virtue, but the form of every virtue at the testing point." C. S. Lewis

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