Author Topic: Propellantless Field Propulsion and application  (Read 666337 times)

Offline Sith

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Re: Propellantless Field Propulsion and application
« Reply #360 on: 05/20/2009 11:15 PM »
". . .There's a reference to the biefield Brown effect, which I know nothing about. . ."

It's a bad joke.  An inefficient ion thruster that does not work as reported.  Easiest way to tell is put it in a box.  The ions accelerated by the potential difference in the design can't get out of the box and the thruster doesn't work at all.  Was shown not to work many years ago.  You can ignore it as junk science.
I don't wanna talk about TT Brown, but this video is interesting.




Offline JohnFornaro

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Re: Propellantless Field Propulsion and application
« Reply #361 on: 05/21/2009 12:40 PM »
The EmDrive is a propellantless propulsion scheme cooked up by Shawyer, and was introduced on this thread some time ago.  There is a bit of chatter here about the math for this theory from about a month ago, and I guess, we're trying to settle the issue to the extent that we can.  I got sidetracked yesterday trying to see how many other people are studying the work of Shawyer, thought I'd post a few of my findings.
Sometimes I just flat out don't get it.

Offline Sith

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Re: Propellantless Field Propulsion and application
« Reply #362 on: 05/22/2009 06:07 AM »
G/I, Star-Drive,

Instead of using H2 fuel cells for the MLT drive, could it be done with simple Lithium-ion batteries??

Offline GI-Thruster

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Re: Propellantless Field Propulsion and application
« Reply #363 on: 05/22/2009 08:03 PM »
Any electrical source can be used to drive an MLT or UFG.  The reason Paul chose GM fuel cells for his WarpStar illustration is that for that application, flying to the Moon and back on a single charge; batteries do not have a high enough energy density.  Fission would not work in such a small craft.  We're still waiting on Fusion.  BLP reactors are still under investigation though, it appears using them instead of a fuel cell would give a WarpStar an exponential extension in range, perhaps enough for travel to Mars.

Given a 1 N/W M-E thruster like what is the baseline assumption for the WarpStar, one might fly to LEO on batteries but not much further and probably have to return hypersonic with wings and tiles.  We talked about this when he was writing the paper but I don't remember all the details.  The key thing to get from this though is that each of these options for storing or generating electrical power have different energy densities, meaning a set amount of energy/mass; so not all of them can accomplish the same things.  Even the best, most cutting edge batteries cannot fly a 1 N/W WarpStar to the Moon and back.

Offline Star-Drive

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Re: Propellantless Field Propulsion and application
« Reply #364 on: 05/23/2009 08:04 PM »
Any electrical source can be used to drive an MLT or UFG.  The reason Paul chose GM fuel cells for his WarpStar illustration is that for that application, flying to the Moon and back on a single charge; batteries do not have a high enough energy density.  Fission would not work in such a small craft.  We're still waiting on Fusion.  BLP reactors are still under investigation though, it appears using them instead of a fuel cell would give a WarpStar an exponential extension in range, perhaps enough for travel to Mars.

Given a 1 N/W M-E thruster like what is the baseline assumption for the WarpStar, one might fly to LEO on batteries but not much further and probably have to return hypersonic with wings and tiles.  We talked about this when he was writing the paper but I don't remember all the details.  The key thing to get from this though is that each of these options for storing or generating electrical power have different energy densities, meaning a set amount of energy/mass; so not all of them can accomplish the same things.  Even the best, most cutting edge batteries cannot fly a 1 N/W WarpStar to the Moon and back.

G/I Thruster & Sith:

The Li-ion battery case for WarpStar-I design is given in the attached slide.  As you will note, assuming the highest ~200 W-hr/kg specific energy density for Li-ion cells, and 1.0 N/W MLTs, we can easily go from the ground, up to geosynchronous orbit, and then back to the ground on one charge even with the final WarpStar-Iís mass of 26,500 kg.  However, the Moon mission doesnít quite make it using even this high end Li-ion energy density.  You would have to use the still unproven Li-Sulphur batteries or EEStorís Cap-Battery with their promises of 400-to-600 W-hr/kg energy density to make it to the Moon and back, and your energy reserves would be reduced as compared to the LOX/hydrogen fuel cellís system energy density of ~1.0 kW/kg.  In other words, the flight to the Moon and back would be doable with the ~500 W-hr/kg Li-S or EEStor batteries, but we would just have to be a lot more vehicle mass conscious than we would when using fuel cells with the payback being lower production and operational costs.

See: http://www.sionpower.com/technology.html
        http://en.wikipedia.org/wiki/EEStor
Star-Drive

Online A_M_Swallow

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Re: Propellantless Field Propulsion and application
« Reply #365 on: 05/23/2009 09:05 PM »
From this thread it is beginning to sound like the propellant depots will have to sell  batteries.  Although swap and recharge may work.

Offline 93143

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Re: Propellantless Field Propulsion and application
« Reply #366 on: 05/23/2009 09:35 PM »
Pff.  If you can go to Earth escape with less than a quarter of the available battery power, you can darn well go to the moon.  Just not without coasting for a couple of days.

Certainly the high-thrust >1g solution makes better copy...

Offline GI-Thruster

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Re: Propellantless Field Propulsion and application
« Reply #367 on: 05/23/2009 09:47 PM »
Yes well, that's my bad.  ;-)  I convinced Paul to pursue the 1 gee solution, meaning constant acceleration from start to finish; because this is part of the paradigm change one is looking at when one looks at electric spacecraft.  Boost and glide is much of what makes space travel not quick and not convenient.  4 days instead of 4 hours.  And after all, the 1 N/W figure though seemingly sensible is somewhat arbitrary.  The point in the WarpStar illustration was not to say "hey look what we can do!" so much as to say "hey look at what space travel could be like!"  I fought for the "safe, quick, convenient, economical" qualification because that's what I believe is necessary for a "golden age of human spaceflight."

But you're right of course.  One could fly from Earth to the Moon and back with 1 N/M MLT's and far less available energy if one were willing to boost and glide.  Then again, one can get around town on a bike with less energy that way.  What do commuter bike riders choose to do?  They pedal all the time because that's quick and convenient.

Paul's WarpStar paper is full of these sorts of practicalities.  For instance, you'll find the notion designs around going fast in space and slow in atmo.  No need for hypersonic re-entries and these cause all sorts of maintenance issues.

This is all simple practicality, modeling future spaceflight to operate much like modern day air travel.  That is after all what works safe, quick, convenient and economical.

Have you read Paul's paper?
« Last Edit: 05/23/2009 09:55 PM by GI-Thruster »

Offline 93143

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Re: Propellantless Field Propulsion and application
« Reply #368 on: 05/23/2009 10:33 PM »
I have not read the paper.  (Or have I?  Okay, I have not read the paper recently.)  I'm no fan of coasting, but Star-Drive seemed to be giving people the impression that the moon trip wasn't possible at all with batteries, and it is.

Batteries.  To the moon.  That's almost as much of a paradigm shift as the fuel-cell-powered 4-hour high-thrust trajectory.

Almost.

Offline GI-Thruster

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Re: Propellantless Field Propulsion and application
« Reply #369 on: 05/24/2009 12:41 AM »
Personally I'd rather see batteries or better, caps.  If you can recharge a spacecraft in a few minutes hooked to some sort of generator, then you have added a whole new level of utility.  Imagine robotic MLT freighters flying cargo to LEO round trip in a couple hours, recharging and flying again, constant transport.  If you're just moving mass, you can fly at very high gee's.

We also talked about fission or fusion powered craft for transport to places like Titan.  If you build something like a Skycrane, that has exterior carriage and can fly a large payload out at 1-2 gees, then return at 10+ gees, you cut the down time, the time the system is not producing to a small fraction.  Dispatchers of all sorts try to do this by managing return trips but they don't generally get to have a truck, taxi or bus make a return trip in 1/10 the time.  All these sorts of things go to what can make a future system economical.

Online A_M_Swallow

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Re: Propellantless Field Propulsion and application
« Reply #370 on: 05/24/2009 03:28 AM »
Providing it is out of sight you can have a nuclear reactor on the ground to recharge your rocket.  In space solar power can recharge the capacitors until about the asteroid belt.

Offline Star-Drive

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Re: Propellantless Field Propulsion and application
« Reply #371 on: 05/26/2009 05:45 PM »
I have not read the paper.  (Or have I?  Okay, I have not read the paper recently.)  I'm no fan of coasting, but Star-Drive seemed to be giving people the impression that the moon trip wasn't possible at all with batteries, and it is.

Batteries.  To the moon.  That's almost as much of a paradigm shift as the fuel-cell-powered 4-hour high-thrust trajectory.

Almost.

93143:

Sorry for making you think that it was impossible.  Yes, with 1.0 N/W G/I thrusters this notional WarpStar-I vehicle design could make it to the Moon and back using only Li-ion batteries.  However, to do so you would have to reduce your average acceleration levels from 1.0 gee down to 1/5 gee to maintain the mission energy reserves assumed in the Warpstar-1 paper.  Of course you could also do the burn and coast approach like rockets use, but why bother?  I like my coffee to stay put when I put it down on the dashboard.  :)

BTW, find attached the WaprStar-1 paper in question and my latest experimental MLT-2009 test article at approximately it's 85% completion point reached over the weekend.  I hope to be testing it by the end of next month.  Predicted thrust levels for this ~175 gram test article using Dr. Woodward's M-E derivation is approximately 52.0 Newton with 100W of input power at 146 MHz, which should generate a cap-ring voltage of ~5,500V-p if my RF loss models are correct.  Using Dr. White's QVF/MHD model for this same test article, under the same operating conditions, the thrust prediction is only ~0.5 gram force (~5.0 milli-Newton).  It should be an interesting test either way...
Star-Drive

Offline Sith

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Re: Propellantless Field Propulsion and application
« Reply #372 on: 05/26/2009 06:53 PM »
Star-Drive, that looks awesome!!!

What are these flat coils on the top?

Offline Star-Drive

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Re: Propellantless Field Propulsion and application
« Reply #373 on: 05/26/2009 10:09 PM »
Sith:

The flat copper coils on top of the white cylinder are eight, one-turn coils clocked every 45 degrees around the MLT's torus that are wired in parallel and form the Lorentz vxB B-field coil assembly for the MLT.  It turned out that configuration yielded the highest peak voltage for the MLT's cap-ring for a given 146 MHz ac input power.
« Last Edit: 05/26/2009 10:09 PM by Star-Drive »
Star-Drive

Offline bpb3

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Re: Propellantless Field Propulsion and application
« Reply #374 on: 05/27/2009 09:23 PM »
Star Drive:  You wrote "Predicted thrust levels for this ~175 gram test article using Dr. Woodward's M-E derivation is approximately 52.0 Newton with 100W of input power at 146 MHz".    Is that 52.0 Newtons for real?  If so then you are halfway to the 1 Newton/Watt needed for the Warp Star.  I wax excited.

Offline Star-Drive

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Re: Propellantless Field Propulsion and application
« Reply #375 on: 05/27/2009 10:24 PM »
bpb3:

As G/I thruster just reminded me, this 52N prediction is based on an excel tool that linearized the M-E wormhole term, which can only be solved accurately by numerical integration, which none of us have figured out how to do yet, so our mileage may vary and vary greatly when it comes to the real deal.   I guess I should not have predicted any anticipated thrust levels publically at this stage of our ignorance and just reported on the actual results when it comes along in a few weeks.  Time will tell.
Star-Drive

Offline khallow

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Re: Propellantless Field Propulsion and application
« Reply #376 on: 05/28/2009 12:54 AM »
Star Drive:  You wrote "Predicted thrust levels for this ~175 gram test article using Dr. Woodward's M-E derivation is approximately 52.0 Newton with 100W of input power at 146 MHz".    Is that 52.0 Newtons for real?  If so then you are halfway to the 1 Newton/Watt needed for the Warp Star.  I wax excited.

Think of it on a logarithm scale, with 1 Newton per 150 MW as your base (for the thrust from a solar sail, the current best propellantless system). If Woodward can achieve that, he is for all practical purposes there.
Karl Hallowell

Offline GI-Thruster

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Re: Propellantless Field Propulsion and application
« Reply #377 on: 05/28/2009 06:49 PM »
Yes well, this isn't Woodward's prediction.  Apart from the fact Woodward's derivation cannot legitimately be used to make thrust predictions inside wormhole territory, it is also true that the mathematical tool Paul is using to get this thrust number is not up to date.  It was constructed by Andrew Palfreyman before Jim realized the necessity of bulk acceleration in these thrusters.  Paul's current build likewise does not accommodate such acceleration so there is an excellent chance that if it works at all, it will produce very small thrusts.  So don't get your hopes up.

Offline Sith

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Re: Propellantless Field Propulsion and application
« Reply #378 on: 05/28/2009 08:56 PM »
inside wormhole territory
Sometimes I get my terms confused. When I see the word "wormhole" I always imagine a shortcut between 2 distant points in space, but instead of that the MLT creates a small fraction of twisted space-time (wormhole) just to get thrust out of it. That's a very witty move :)


it will produce very small thrusts.  So don't get your hopes up.
The question is how long could it sustain in a vacuum chamber. Any preparations for that kind of demonstration?

Offline Star-Drive

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Re: Propellantless Field Propulsion and application
« Reply #379 on: 05/28/2009 10:38 PM »
Yes well, this isn't Woodward's prediction.  Apart from the fact Woodward's derivation cannot legitimately be used to make thrust predictions inside wormhole territory, it is also true that the mathematical tool Paul is using to get this thrust number is not up to date.  It was constructed by Andrew Palfreyman before Jim realized the necessity of bulk acceleration in these thrusters.  Paul's current build likewise does not accommodate such acceleration so there is an excellent chance that if it works at all, it will produce very small thrusts.  So don't get your hopes up.

G/I Thruster:

I never said that the noted M-E prediction tool was authored by Dr. Woodward.  And I have posted previously in this forum that this M-E predictive spreadsheet tool was coauthored with Andrew Palfyreman and myself in our STAIF-2006 paper, which is aviailable on the web, warts and all.  Whether you think it is applicable to an MLT operated where the wormhole term is excited is your take on this situation, but in the final analysis it is only knowable by experiment, which will soon be accomplished and reported on.

BTW, the MLT-2009 was designed from the get-go to accomodate the bulk acceleration conjecture by Nembo Buldrini.  In other words, this test article's Teflon cap-ring has electrical leads that will accomodate cyclic Z-axis motions and the cap-ring is potted in a silicone material that will act as both a suspention spring and an electrical insulator as shown in the attached slide.  Again only experimental data will tell us whether this blend of electric, magnetic, and mechancial design compromises used to build this test article will be an MLT winner or a dud. 
« Last Edit: 05/29/2009 03:14 AM by Star-Drive »
Star-Drive

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