Mach Effect progress

Point out news stories, on the net or in mainstream media, related to polywell fusion.

Moderators: tonybarry, MSimon

GIThruster
Posts: 4686
Joined: Tue May 25, 2010 8:17 pm

Postby GIThruster » Sun Dec 09, 2012 12:54 am

kurt9 wrote:I don't follow the criticism on the Nasa Starflight blog or anywhere else.

I think Fuerst's mistake is in generalizing, and equating all propellantless solutions to violations of conservation. He's then going on to say Jim get's this violation because he's using a vector theory. What he doesn't realize is Jim neither starts nor ends with such a violation, and the reason he doesn't get this is he hasn't read Jim's papers. He's merely projecting his presuppositions onto the work of others.
"Courage is not just a virtue, but the form of every virtue at the testing point." C. S. Lewis

ScottL
Posts: 1108
Joined: Thu Jun 02, 2011 11:26 pm

Postby ScottL » Sun Dec 09, 2012 1:44 am

Is there any word on scaling experiments? I'm not on the list, so what little I hear is usually from GIT or a handful of others here. I'm willing to believe there is an effect, but I'm hesitant to jump on the bandwagon (that this is a solution) until we start seeing some non-trivial scaling experiments.

GIThruster
Posts: 4686
Joined: Tue May 25, 2010 8:17 pm

Postby GIThruster » Sun Dec 09, 2012 2:40 am

Jim has produced some scaling evidence in the past but not since he started showing these much larger thrusts. I think scaling studies are on the agenda but he has been busy dispensing with the charges he has a dean-drive type friction effect lately by using rubber washers that attenuate the vibrational effects on the balance. If the thrust were some sort of dean-drive effect, it would reduce when the vibrational noise on the balance reduces with the washers and it does not. So those tests were the most recent (last week) and successful. I've no idea what he plans next.

I would note that scaling with frequency is a difficult thing to do with the setup he has, because each thruster produces the large thrusts it does only when in resonance, both electrical and acoustic. The acoustic resonance is set by the thickness of the ceramic so the only way to generate scaling with frequency is to change thrusters out. He can do this, but the number of points one can thus plot doesn't make for particularly impressive parametric studies. One really wants more data points for such a study, which would require dozens of separate thrusters.

Better is to achieve resonance, and demonstrate scaling with voltage, which he has done before with good results.
"Courage is not just a virtue, but the form of every virtue at the testing point." C. S. Lewis

GeeGee
Posts: 95
Joined: Fri Jun 10, 2011 7:00 pm

Postby GeeGee » Sun Dec 09, 2012 7:04 pm

Lots of enthusiasm on Harold White's Eagleworks at reddit. If you scroll down, you'll find a comment by someone who was an intern at his lab.

http://www.reddit.com/r/science/comment ... es_of_the/

paulmarch
Posts: 155
Joined: Tue Sep 08, 2009 7:06 pm
Location: Friendswood, TX USA

Postby paulmarch » Mon Dec 10, 2012 5:12 am

GIThruster wrote:Jim has produced some scaling evidence in the past but not since he started showing these much larger thrusts. I think scaling studies are on the agenda but he has been busy dispensing with the charges he has a dean-drive type friction effect lately by using rubber washers that attenuate the vibrational effects on the balance. If the thrust were some sort of dean-drive effect, it would reduce when the vibrational noise on the balance reduces with the washers and it does not. So those tests were the most recent (last week) and successful. I've no idea what he plans next.

I would note that scaling with frequency is a difficult thing to do with the setup he has, because each thruster produces the large thrusts it does only when in resonance, both electrical and acoustic. The acoustic resonance is set by the thickness of the ceramic so the only way to generate scaling with frequency is to change thrusters out. He can do this, but the number of points one can thus plot doesn't make for particularly impressive parametric studies. One really wants more data points for such a study, which would require dozens of separate thrusters.

Better is to achieve resonance, and demonstrate scaling with voltage, which he has done before with good results.


Ron:

Woodward demosntrated his latest JPC paper's M-E predicted w^6 frequency thrust output scaling for his PZT-Stacks when the PZT-Stack started to generate the 4th harmonic force rectifcation signal via the PZT stack's electrostricitive response. This occurred when the stack's nominal 1-w 35 kHz thrust output of ~2 uN with ~1.0W dissipated input power jumped up to ~130 uN when Woodward managed to get the stack's accelerometer and input power signals to match up temporally. Of coruse that was under "just-so" stack tunning conditions that are still VERY tempromental to obtain and maintain.

Best,
Paul March
Friendswood, TX

paulmarch
Posts: 155
Joined: Tue Sep 08, 2009 7:06 pm
Location: Friendswood, TX USA

Postby paulmarch » Mon Dec 10, 2012 5:20 am

GeeGee wrote:Lots of enthusiasm on Harold White's Eagleworks at reddit. If you scroll down, you'll find a comment by someone who was an intern at his lab.

http://www.reddit.com/r/science/comment ... es_of_the/


GeeGee:

I'd wait for some reported data before getting too exciting about the stuff comming out of the Eagleworks Lab. We should know a lot more on both the warp-field interferometer and Q-Thruster torque pendulum tests by the end of next summer and maybe bit sooner.

Best,
Paul March

Friendswood, TX

chrismb
Posts: 3161
Joined: Sat Dec 13, 2008 6:00 pm

Postby chrismb » Mon Dec 10, 2012 10:28 am

paulmarch wrote:This occurred when the stack's nominal 1-w 35 kHz thrust output of ~2 uN with ~1.0W dissipated input power jumped up to ~130 uN


Paul, at such a comment, chrismb would have asked something like "If a craft was moving at 100,000 m/s then would a 130uN thrust not mean that its rate of kinetic energy gain would be 13 J/s, and if so is this not a contradiction to an input energy of 1 W?"

Does this imply there is a maximal speed at which this device will work, and if so then a velocity relative to what?

Once there is a method wherein the rate of gain of kinetic energy can exceed the power input, then it is a short hop to a machine that can create energy from nothing.

GIThruster
Posts: 4686
Joined: Tue May 25, 2010 8:17 pm

Postby GIThruster » Mon Dec 10, 2012 11:24 am

Chris, we've been all through this here, at NSF and at NBF. You can use the same argument about a rocket on a flywheel, so obviously your argument reduces to absurdity.

Jim has already explained the proper way to do the math by taking the summation of instantaneous frames of reference or some such that I do not have the mathematics background to explain, and neither do you. And this is why this same objection comes up again and again from people other than the physicists who have reviewed this in peer review--because trolls like you would rather make an objection in ignorance than simply try to learn something.

How many times are you going to promise to go away chris? Please go away and stop creeping everyone out with the third person references.
"Courage is not just a virtue, but the form of every virtue at the testing point." C. S. Lewis

chrismb
Posts: 3161
Joined: Sat Dec 13, 2008 6:00 pm

Postby chrismb » Mon Dec 10, 2012 11:27 am

GIThruster wrote: You can use the same argument about a rocket on a flywheel,


Not at all. The kinetic energy gain of a rocket or turbofan powered machine will never exceed the chemical energy consumed. This would be absurd if it were otherwise.

GIThruster
Posts: 4686
Joined: Tue May 25, 2010 8:17 pm

Postby GIThruster » Mon Dec 10, 2012 11:35 am

That's right, and the kinetic energy gain of an M-E powered craft cannot exceed the energy consumed either. If you use the same reasoning that dv is linear and dE is quadratic, you will get the same absurd result for a rocket on a flywheel.

It should be obvious your example applies equally as well to a Hall thruster as it does to an M-E thruster, and you are thus doing the math wrong.

Now please go away.
"Courage is not just a virtue, but the form of every virtue at the testing point." C. S. Lewis

chrismb
Posts: 3161
Joined: Sat Dec 13, 2008 6:00 pm

Postby chrismb » Mon Dec 10, 2012 12:48 pm

GIThruster wrote:That's right, and the kinetic energy gain of an M-E powered craft cannot exceed the energy consumed either. ...
It should be obvious your example applies equally as well to a Hall thruster as it does to an M-E thruster, and you are thus doing the math wrong.


Not at all. These devices will run out of substance to thrust before the maths becomes compromised, because they have to eject some of the mass of the craft. They are figuratively dependent on their rest mass before they commenced the acceleration. The power consumed will be exactly related to the kinetic energy content ejected, and/or gathered en route.

State which line the error of premise occurs:
1) A 1 kg test thruster is subjected to a 1 W, 130 uN of thrust.
2) It accelerates for 10 years (call it 300 Ms) from a given rest frame at which it was at 0 m/s.
3) 300 MJ has been expended.
4) The test thruster is travelling at 39,000m/s (it'll have reached 3.6 bn miles by then ... a trip to Neptune!)
5) Its kinetic energy wrt the given rest frame is then 760 MJ, which is greater than the 300 MJ expended.

CaptainBeowulf
Posts: 498
Joined: Sat Nov 07, 2009 12:35 am

Postby CaptainBeowulf » Mon Dec 10, 2012 6:25 pm

This complaint about accumulating more kinetic energy than power consumed - going over-unity because you have continuous thrust - seems to be at the heart of the remaining objections of Chris, GoatGuy and SFuerst. They all had other objections, but IMO those other objections have been adequately dealt with. However, I still don't really follow how the continuous thrust thing is addressed.

GIT, can you once again re-link to wherever Jim has discussed the summation of instantaneous frames of reference thing? I want to try to figure it out, although my math knowledge is likely inadequate... but hopefully I can follow the reasoned argument.

I still like the conjecture that something like the Higgs field creates drag on a M-E thruster which decreases its efficiency whenever it approaches a locally over-unity situation, but this is rather like grasping at a straw.

GIThruster
Posts: 4686
Joined: Tue May 25, 2010 8:17 pm

Postby GIThruster » Mon Dec 10, 2012 7:59 pm

I don't have that previous explanation handy. It is however not necessary.

chris' contention that rockets don't demonstrate this problem is bullshit. Put a rocket on a flywheel and feed it propellant through the moment arm just as with Roton and you have precisely the same curiosity pop up. That's because we don't normally do the math properly. Just as when we do vector addition, we can normally use Newtonian mechanics and get away with it, we can for short periods of time get away with doing the math improperly in this instance. However, the same objection chris, goatguy, Andrew Palfreyman and others at NSF have had has been answered several times now over the years, and it's important to note that it will come up several more times in the coming years. (Steven Feurst's objection is a different one. It's not fair to say he made this mistake.)

This is because the people making the complaint don't understand the relevant math. Rather, they in general understand how to be a troll. When you have a simple counter-example that clearly demonstrates the method being used to come up with a conservation violation generates an absurd conclusion that applies equally as well to all rockets, it is obvious that the method is wrong. And that is enough an answer.

Just take the simple case chris offered: "If a craft was moving at 100,000 m/s then would a 130uN thrust not mean that its rate of kinetic energy gain would be 13 J/s, and if so is this not a contradiction to an input energy of 1 W?" Substitute the thruster in this example with a Hall or Ion thruster and you have THE SAME RESULT. It doesn't matter how the thruster gets to 100,000 m/s. All satellites in GSO are moving a lot faster than this in the Earth reference frame they were launched in and their Hall thrusters are putting out this kind of thrust. Are they all violating conservation? Of course not. What about Deep Space 1? Calculating in the manner chris is recommending, it has been over-unity since it first had its Ion engines kick in.

I should note to you here, that Jim never defends himself against cranks like chris. He knows there are still nut cases out there that think Newton and Einstein were wrong. Especially trolls like chris, think they're going to prove themselves clever by peeing on the leg of an elephant. If there are still whack jobs who claim Newton and Einstein are wrong, there are most certainly going to be trolls who say Woodward is wrong, and they are not worth answering past showing conclusively they are doing the math wrong.
"Courage is not just a virtue, but the form of every virtue at the testing point." C. S. Lewis

93143
Posts: 1130
Joined: Fri Oct 19, 2007 7:51 pm

Postby 93143 » Mon Dec 10, 2012 8:40 pm

If you're going to assess energy conservation in a thruster, you have to account for both the thruster (and whatever's attached to it) and its propellant. This is what makes rockets conserve energy - the chemical energy in the propellant is converted into a fixed amount of kinetic energy inherent in the velocity difference between the rocket and its exhaust.

That is, if you take the sum of the kinetic energy of the spacecraft and its propellant before and after the propellant is used, the difference is the chemical energy of the propellant times the efficiency of the rocket.

Single-velocity kinetic energy is frame-dependent. Velocity-difference kinetic energy is not.

With M-E, the reaction mass is some possibly-weighted subset of the rest of the universe. What is the velocity of this subset before and after being pushed on? Presumably the values are such that energy is conserved, if the thruster works.

See, it's not at all trivial to show that M-E thruster operation violates conservation of energy. The device can easily be assigned a notional behaviour that doesn't. Whether this leads to an entropy condition violation is a separate question; I have been assured that it doesn't, but I'd rather get into the math myself when I have the time...

...

GoatGuy and chrismb are making a dead argument; it has been disassembled repeatedly. They are drawing the box too small. M-E thrusters have never been claimed to push on nothing. If the thrusters are supposed to be pushing on something, you have to include that something in your assessment of conservation of energy. They didn't. Their argument is therefore invalid.


Return to “News”

Who is online

Users browsing this forum: No registered users and 2 guests