Author Topic: Propellantless Field Propulsion and application  (Read 663579 times)

Offline GI-Thruster

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Re: Propellantless Field Propulsion and application
« Reply #300 on: 05/02/2009 09:13 PM »
Here's a vid of the rotator in operation.  I have not yet been able to get it to play.  This may be because zshare is just overwhelmed.  The 13GB file had already been DLed 6 times in the few minutes between when Jim sent this out and when I tried to view it.  It could also be because my machine and ISP are somewhat bandwidth challenged and often give trouble with vids.  Also take note that the ARC Lite in the vacuum chamber is a different experiment than the rotator.  Jim is just busy pumping out the chamber for a thruster study.
---------------
Gentlefolk,

You can now watch the rotary device in operation at ZShare.  The link is:
<http://www.zshare.net/video/59506760a6754bd2/>.  I hereby make the
implicit copyright explicit.  No distribution or use for profit without
my prior consent.

The first part of the video shows the device being cycled through a run
from 0 Hz to 60 Hz and back to 0.  At the higher speeds you can hear the
whine of the drive over the vacuum pump background noise (which is
keeping the ARC Lite balance chamber pumped out).

The second part of the video shows the instrumentation displays.  On the
left are the three oscilloscopes used.  The two analog scopes show the
capacitor voltage as one trace.  It is used as a phase reference for the
other traces.  On the lower scope the other trace is the full, broad
bandpassed differential accelerometer trace.  This output is also fed
into the Picoscope as one of its two inputs (along with the capacitor
voltage).  The trace on the upper analog scope is the isolated second
harmonic (80 KHz) present in the accelerometer trace displayed on the
lower scope.  The amplitude and phase variation of this trace is the
matter of interest in this business.  The top digital scope displays the
amplitude and phase adjusted individual accelerometer outputs (and the
red trace is the difference of the yellow and blue traces).

In the lower center is an old Monsanto counter (nixie tubes!).  The dope
who designed it thought you would like to see the counts in progress, so
the display shows that rather than the previous proximate count value
while counts are taking place.

On the right is the display of the power spectra of the differential
accelerometer (blue) and capacitor voltage (red).  Normally, for
quasi-stationary measurements the "average" mode (rather than "normal")
would be used to suppress transient noise.  But the settling time in that
mode is 5 to 10 seconds, so it is not used as the changes in rotation
speed take place too quickly for the average mode to track correctly.

The run shown in the video is for 40 KHz, 0 - 60 Hz, 6 KV amplitude (the
traces on the scopes are 1 KV/volt, and the scale is 2 volt/div).  Watch
the phase and amplitude changes of the second harmonic.  The 0 Hz signal
is electrostriction.

Have fun,

Jim

Offline Nathan

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Re: Propellantless Field Propulsion and application
« Reply #301 on: 05/03/2009 05:44 AM »
How does Shawyer get v = group velocity in his "emdrive"? The "v" is the velocity of the charge, not the wave, and is << c.


It is a well known property of waveguides that the group velocity of light varies with the diameter of the waveguide.
see pg392 of "introduction to electrodynamics 2nd edition" by David Griffiths, published by Prentice Hall.

I still cannot come up with an other analogy for how the em drive works other than the mach thruster also discussed on this thread. Emdrive approaches the problem from the point of view of a varying velocity and mach drive (woodward drive) relies on varying mass. The end result is the same though - forward motion.
Given finite cash, if we want to go to Mars then we should go to Mars.

Offline Nathan

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Re: Propellantless Field Propulsion and application
« Reply #302 on: 05/03/2009 06:06 AM »


I still cannot come up with an other analogy for how the em drive works other than the mach thruster also discussed on this thread. Emdrive approaches the problem from the point of view of a varying velocity and mach drive (woodward drive) relies on varying mass. The end result is the same though - forward motion.


Actually - it may be more related to the mach effect than I first considered. If the group velocity is different at each end of the cavity then the momentum is different. The momentum term contains mass and the mach effect determines what that mass is. (we are talking photonic mass not actual rest mass here, of course) If however, in the emdrive the mass stays the same then the mach effect suggests that the distant matter in the universe would experience a velocity change instead.
That's interesting. A changed velocity here could mean a changed velocity "of the distant stars", thus allowing forward momentum of the vehicle without getting around newton's laws.
I'm going to have to look into this whole mach effect thing. I don't think it is needed as the emdrive equations conserve momentum and energy already but further investigation is always worth it to see if they are only one half of a larger story.
Given finite cash, if we want to go to Mars then we should go to Mars.

Offline GI-Thruster

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Re: Propellantless Field Propulsion and application
« Reply #303 on: 05/03/2009 12:39 PM »
The notion of "group velocity" is not intended for book-keeping momentum.  If you want to talk about the momentum of light, you have to talk about photons and they always move at c.  Group velocity has nothing to do with momentum and Shawyer's device is indeed proposing a violation of conservation of momentum.

Lots of physicists have looked at this and there's a reason Shawyer lost his funding from the British government.  His physics is wrong and his thruster has nothing in common with M-E thrusters.

Offline Lampyridae

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Re: Propellantless Field Propulsion and application
« Reply #304 on: 05/08/2009 02:40 AM »
"And, 400 watts from a cork sized battery?  I don't have access to this technology.  Is this actually a capacitor battery, one that you charge the heck out of and then can use to power the thrusters?"

Yes, these are the new batteries from A123 that will be powering the next generation of electric vehicles like the Chevy Volt.  I picked up a test kit with 3 of these cells a year or two ago and sent it to a PhD EE friend who benched them for me.  They do indeed put out over 400 watts each and have a C rating of more than 40.  But they're batteries, not supercaps.  The barium titaniate "supercap" technology from EEStor is reported to have an even higher power density but that's not on the market yet.

That's awesome. Handheld lasers here we come!!

Quote
And BTW, yes I know GOCE doesn't have the Isp of Deep Space 1, but for a first application of a low thrust efficiency M-E thruster, we are probably looking at satellite station keeping, not robotic travel to Jupiter's icy moons.  So GECO really is the more applicable technology to compare against.  So far, the discovery phase lab experiments seem to have a huge advantage over the cutting edge-tech on GECO.

Someone tell me if I remember correctly--NASA spends $50 million annually boosting hydrazine to ISS to keep her on orbit?  If we had commercial thrusters with efficiencies like what Paul saw, we could replace all the hydrazine on ISS and save about half a billion dollars over the course of a decade.  That's just one application.


The issue of hydrazine handling and leakage alone should make the case for this (not that we can't handle hydrazine, it's just a pain in the rear and always will be). And add to that no need for a clear line of thrust and no risk of exhaust contamination of experiments... this would be an awesome system. Especially if the caps could be made to last longer (replacement every 6 months or so).
« Last Edit: 05/08/2009 02:41 AM by Lampyridae »
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Offline GI-Thruster

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Re: Propellantless Field Propulsion and application
« Reply #305 on: 05/08/2009 08:29 AM »
"The issue of hydrazine handling and leakage alone should make the case for this (not that we can't handle hydrazine, it's just a pain in the rear and always will be). And add to that no need for a clear line of thrust and no risk of exhaust contamination of experiments... this would be an awesome system. Especially if the caps could be made to last longer (replacement every 6 months or so). "

There's a huge amount of utility in the fact that gravinertial thrusters don't have to be placed outside a spacecraft.  Since they have no exhaust, you can place them anywhere you please and this makes up-keep much easier.

So far as the die-off issue is concerned, we haven't had the finances to do destructive analysis of played out thrusters, but this appears to concern things like depolarization.  If that proves to be the case, then using non polarized ceramics like PMT-PT will solve the issue all at once.  It still seems very likely M-E thrusters will have no ageing issues once they go online.

Offline mlorrey

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Re: Propellantless Field Propulsion and application
« Reply #306 on: 05/08/2009 07:32 PM »
"The issue of hydrazine handling and leakage alone should make the case for this (not that we can't handle hydrazine, it's just a pain in the rear and always will be). And add to that no need for a clear line of thrust and no risk of exhaust contamination of experiments... this would be an awesome system. Especially if the caps could be made to last longer (replacement every 6 months or so). "

There's a huge amount of utility in the fact that gravinertial thrusters don't have to be placed outside a spacecraft.  Since they have no exhaust, you can place them anywhere you please and this makes up-keep much easier.

Aye, now Scotty can have a real engine room to call the captain from...

Quote

So far as the die-off issue is concerned, we haven't had the finances to do destructive analysis of played out thrusters, but this appears to concern things like depolarization.  If that proves to be the case, then using non polarized ceramics like PMT-PT will solve the issue all at once.  It still seems very likely M-E thrusters will have no ageing issues once they go online.

Ceramic capacitors are very durable, I've used them on Marx Ladder HV power supplies for years. The RTV potting breaks down first.
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Offline GI-Thruster

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Re: Propellantless Field Propulsion and application
« Reply #307 on: 05/08/2009 09:23 PM »
They are durable but we've had thrust die-off issues in the past and the ageing here is well in advance of normal ageing in normal use of these caps.  There's something going on we haven't had the opportunity to check into yet.  We do know that if you bake the caps they return for a time to their original abilities but they die off again.  So what is going on here?  These caps are not generally polarized to start.  Could the thrust be forcing the tetrahedrons off axis so that instead of a chaotic, generally unpolarized state they are polarized off axis?  We haven't even taken the opportunity to polarize these caps for a single run though, that is easy to do when the time comes.

There are other possibilities.  What if the mobile ions are quantum tunneling out of the lattice while they're fluctuated light and moving fast?  That would leave a net charge on the lattice and once again, we haven't had the time and resources to check.  The ultimate in destructive analysis is to stick a failed cap under a scanning electron microscope--easy to do if you have the funds. . .

Offline Nathan

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Re: Propellantless Field Propulsion and application
« Reply #308 on: 05/10/2009 03:56 AM »
The notion of "group velocity" is not intended for book-keeping momentum.  If you want to talk about the momentum of light, you have to talk about photons and they always move at c.  Group velocity has nothing to do with momentum and Shawyer's device is indeed proposing a violation of conservation of momentum.

Lots of physicists have looked at this and there's a reason Shawyer lost his funding from the British government.  His physics is wrong and his thruster has nothing in common with M-E thrusters.

Remember in this case we are not in a true vacuum, rather we are in a waveguide. Dispersion of the wave group needs to be accounted for. http://en.wikipedia.org/wiki/Group_velocity.

Shawyers device moves by recoiling from the net force at the end plates. This conserves momentum. The motion is actually in the opposite direction to the net thrust, which confirms the conservation of momentum.

(I finally found a simple description!) One really has to sit down and work thru the equations to understand it. I'd encourage everyone to do it. Persevere! The knee-jerk reaction is to dismiss it. I did so on several occasions but kept getting pulled back into it due to the fact that the math worked. Also there was that video of a test thruster actually working....
so:
The emdrive achieves motion in reaction to the net force on the end plates in an equal and opposite magnitude.

The net force exists due to the differing group velocities at each end of the waveguide.

Relativistic velocity addition is required due to the relativistic velocities involved, which implies that the photons at each end are in different reference frames.

Given finite cash, if we want to go to Mars then we should go to Mars.

Offline JohnFornaro

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Re: Propellantless Field Propulsion and application
« Reply #309 on: 05/11/2009 01:56 PM »
Somebody correct me if I'm wrong, but group velocity is the velocity of a wavefront, or per Wiki, the modulation or envelope of a wave.  It is a velocity, but it is not a velocity of something, that is, it is not a velocity of mass.  It is also not the velocity of a signal carrying information, which is also something less than or equal to c.

Backing up to the Wiki article, the matter wave group velocity is also just a velocity, not a velocity of matter.  How does Shawyer get work done, when all he is using is a velocity on which to hang his theory?
Sometimes I just flat out don't get it.

Offline Lampyridae

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Re: Propellantless Field Propulsion and application
« Reply #310 on: 05/14/2009 01:01 AM »
They are durable but we've had thrust die-off issues in the past and the ageing here is well in advance of normal ageing in normal use of these caps.  There's something going on we haven't had the opportunity to check into yet.  We do know that if you bake the caps they return for a time to their original abilities but they die off again.  So what is going on here?  These caps are not generally polarized to start.  Could the thrust be forcing the tetrahedrons off axis so that instead of a chaotic, generally unpolarized state they are polarized off axis?  We haven't even taken the opportunity to polarize these caps for a single run though, that is easy to do when the time comes.

There are other possibilities.  What if the mobile ions are quantum tunneling out of the lattice while they're fluctuated light and moving fast?  That would leave a net charge on the lattice and once again, we haven't had the time and resources to check.  The ultimate in destructive analysis is to stick a failed cap under a scanning electron microscope--easy to do if you have the funds. . .

I would venture that the B-field is putting added stress on the cap. Rank speculation on my uneducated part follows.

 Perhaps the M-E fluctuation field also screws things up on a very local scale. Such as nano-scale chaotic gravitational fluctuations within the cap might be stressing the structure. Especially if your ions are moving at "wormhole term" acceleration changes. All sorts of weird crud could be spilling out in individual locations. Most other experiments shoving ions around deal with amorphous plasmas, so perhaps this is something that otherwise wouldn't show up here?
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Offline GI-Thruster

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Re: Propellantless Field Propulsion and application
« Reply #311 on: 05/14/2009 01:41 AM »
My own guess is that this thrust die-off is a consequence of the tetrahedrons being forced off axis and essentially polarizing orthogonal to the thrust axis.  The caps start off chaotic--no polarization--and when played out ceramics are baked, they regain their thrust signature.  Baking would have the effect of bringing the ceramic back to a chaotic, unpolarized state.  What we need to do are studies where we're repolarizing the ceramic.  This is easy to do.  We can even do it without removing it from the thrust balance by heating it above Curie (by running it), leaving some HV DC on it and letting it cool.

Since these thrusters make use of the piezoelectric effect, and that effect is greatest when BaTiO3 is in it's cubic, unpolarized phase (above Curie), running the caps hot has a lot to recommend it as well.  That was where Paul March got the greatest results in his MLT tests, above Curie.

Just so much to do and so little time, and Jim leaves for his 3 month break at the end of this week.

Offline Sith

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Re: Propellantless Field Propulsion and application
« Reply #312 on: 05/14/2009 06:27 AM »
From all I read the conclusion I make is that with electromagnetism you can affect space-time.

Offline GI-Thruster

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Re: Propellantless Field Propulsion and application
« Reply #313 on: 05/14/2009 12:39 PM »
The only way I know how to do this is by using Mach Effects according to Jim Woodward's theory.  It's true that M-E does affect space-time by kinking the gravinertial field that connects all matter in the universe.  However, rather than call it "space-time" it's probably best to precise that it affects the gravinertial field within space-time.

Offline JohnFornaro

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Re: Propellantless Field Propulsion and application
« Reply #314 on: 05/14/2009 12:57 PM »
I have been studying Mahood's thesis on and off over the last several weeks.  He admits that the ORNL refutation of his experimental work has some validity, but insists that further experimentation will validate his results.  Could someone post a more recent PDF of Mahood and Woodward's math and experimental work?

Mahood's math is gnarly for me, but I'm working thru the equations in his thesis appendix one by one, in case anybody is wondering, or even cares.

However, thrust efficiency is a major stumbling block, if the current (1999) readings are taken as accurate.  If my tentative suggestion of newtons per watt as a unit of measure is acceptable, the power supply for such a thruster would be distressingly large for the amount of thrust generated.

In addition, he is ignoring local gravitational effects, such as the planet Earth, in favor of distant gravitational effects, which are several orders of magnitude smaller. I don't understand the derivation of his justification for this.

Further, the thesis offers no insight as to what I understand to be the tapping of some other energy source to provide momentum.  This has to do mass fluctuations in excess of 100%, so there seems to be more recent math which I would appreciate reviewing.

Finally,  the mass fluctuations of the Ti ion appear to take place at non-relativistic speeds.  What is the math behind this assertion?
Sometimes I just flat out don't get it.

Offline GI-Thruster

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Re: Propellantless Field Propulsion and application
« Reply #315 on: 05/14/2009 01:14 PM »
John, I appreciate all these questions but the only way to get the answers is to go on the two web sites provided and read the papers.

Try to remember, Tom Mayhood was Jim's graduate student.  Tom is an engineer, not a physicist.  The math with regards M-E theory is Jim's math.  That's the gnarley stuff because it's field theory.  If you can't do general relativity, you're not going to do this part of the math.  But you don't have to. It was all peer-reviewed more than a decade ago and came through shining.

In any event, there are lots of more recent papers.  You're reading one of the oldest.  If you want to understand pure theory better, read the papers by Jim from a decade ago.  If you want to understamnd the engineering behind the most recent tests, you'll want to ask for copies of Jim's STAIF papers the last few years.  For copyright reasons Jim has no control over, the STAIF papers cannot be posted online but I'm sure Paul March can send you some privately if you like.  But truly, there are at least a dozen papers posted online that you could go through first.

Offline GI-Thruster

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Re: Propellantless Field Propulsion and application
« Reply #316 on: 05/14/2009 01:22 PM »
You can find some of the papers here:

http://physics.fullerton.edu/Woodward.html

. . .Unfortunately, I am leaving in a few days for a 3 week stint at a caving expedition to Mexico (http://www.usdct.org if you are interested--and no I am not insane enough to dive in-cave), so it will be a while before I can sit down and really absorb them. 


Anyone know if Blazotron made it out of the cave alive?

Offline JohnFornaro

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Re: Propellantless Field Propulsion and application
« Reply #317 on: 05/14/2009 02:28 PM »
The papers published are exactly the papers I have read. Not only are they a decade old, they are also a decade old.  Your suggestion above is confusing to me.  It seems to suggest that the... well, I don't know exactly what it suggests.

Anyhow, I have contacted Mr. Woodward.  PM me with Paul March's email, if you don't mind.
Sometimes I just flat out don't get it.

Offline Sith

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Re: Propellantless Field Propulsion and application
« Reply #318 on: 05/14/2009 03:55 PM »
What about the Onion Drive? I saw it's theory in the aiaa presentation 2008.

http://www.aiaa-la.org/flyers/Adv%20Space%20Propulsion%20for%20Interstellar%20Travel%20-%20GMeholic%20042408.pdf

Slide 34/55


Is it equal to the MLT thruster?

Offline GI-Thruster

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Re: Propellantless Field Propulsion and application
« Reply #319 on: 05/14/2009 07:44 PM »
No.  It's junk science.  I was just asked my analysis of this yesterday.  Since my response, half a dozen physicists have responded about how the physics doesn't work either.  It's all junk.

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