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Thrust Without Fuel

08/04/2014 4:48 AM

Here's a mighty interesting invention/concept:

http://www.gizmag.com/cannae-reactionless-drive-space-propulsion/33210/?utm_source=Gizmag+Subscribers&utm_campaign=5c48ebf212-UA-2235360-4&utm_medium=email&utm_term=0_65b67362bd-5c48ebf212-90567161

What worries me a bit is this:

"Even beyond that, Shawyer claims that the second generation of his fuel-less thrusters, based on superconductor technology, will be capable of producing an impressive specific thrust of 30 kN per kW of input energy. "Thus for 1 kilowatt (typical of the power in a microwave oven) a static thrust of 3 tonnes (3.3 tons) can be obtained, which is enough to support a large car. This is clearly adequate for terrestrial transport applications."

1 kW could yield 3 tonnes of thrust? I don't get it!

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Guru

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#1

Re: Thrust without fuel

08/04/2014 6:51 AM

Replying to myself: This whole thing smacks of Pons/Fleischman's Cold Fusion claims.

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#18
In reply to #1

Re: Thrust without fuel

08/05/2014 3:07 AM

Really? Not bullshine as well, then?

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#2

Re: Thrust without fuel

08/04/2014 8:04 AM

Firstly, a kilowatt is not a unit of energy; it is a unit of a rate of energy.

Secondly, a magnet can develop such a thrust, without using any power at all.

So the odour of bovine excreta should be all-pervading.

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#3

Re: Thrust without fuel

08/04/2014 8:08 AM

Without fuel???

Errr but it says an input energy of umpteen kW of electricity.
If electricity isn't fuel why am I paying for it back here on Earth?
Del

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#5
In reply to #3

Re: Thrust without fuel

08/04/2014 10:02 AM

Thrust without propellant. There is still energy input.

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#6
In reply to #5

Re: Thrust without fuel

08/04/2014 10:04 AM

Its units don't make sense as written.

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#4

Re: Thrust Without Fuel

08/04/2014 9:58 AM

Totally agree with you that there is no supporting evidence for Shawyer's statement- note that it is clearly a projection, not a statement of having done so- but what did you expect from gizrag?

On the other hand, the Phoenicians managed to build an empire with reactionless drives (OK, not truly so but according to the definition in the article it would be!!).

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#7

Re: Thrust Without Fuel

08/04/2014 10:05 AM

A weight at height could produce thrust. Something doesn't make sense.

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#8

Re: Thrust Without Fuel

08/04/2014 10:13 AM

This article makes no sense to me. A resonant cavity can accelerate bursts of charged particles very nicely. The only thing this article discusses is the radio frequency energy pumped into the cavity, there is no mention at all about charged particles. Are all of these fantastic claims of thrust purely from the RF photons produced? Then there's the preposterous leap of four decades of magnitude for switching to a superconducting cavity with similar power applied. That normal conduction cavity had to be getting really hot to be wasting that much power.

I guess Gizrag once again mangled another scientific paper.

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#9

Re: Thrust Without Fuel

08/04/2014 11:11 AM

I would have to say I'm skeptical. I have a deep seated religious belief in the Law of Conservation of Momentum.

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#17
In reply to #9

Re: Thrust Without Fuel

08/05/2014 3:06 AM

One could always add-in the Laws of Thermodynamics!

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#10

Re: Thrust Without Fuel

08/04/2014 12:36 PM

Engage the warp drive Scotty....

I canno make 'er go without the dilithium crystals captain...

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#12
In reply to #10

Re: Thrust Without Fuel

08/04/2014 4:03 PM

Is that Conan O'Brien at Uhura's communication station?

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#11

Re: Thrust Without Fuel

08/04/2014 3:56 PM

The phenomena seems to be real, but the claims by the inventor of thrust output are orders of magnitude higher compared to what has actually been physically replicated in the lab.

Are superconductors the new anti-gravity over-unity pseudoscience engine?

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#13

Re: Thrust Without Fuel

08/04/2014 7:15 PM

OK, I'm trying to make my microwave oven levitate. What am I doing wrong?

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#19
In reply to #13

Re: Thrust Without Fuel

08/05/2014 3:10 AM

Not enough RDX, in all probability...

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#14

Re: Thrust Without Fuel

08/04/2014 8:03 PM

Here is a paper on the theory of operation...

http://www.newscientist.com/data/images/ns/av/shawyertheory.pdf

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#20
In reply to #14

Re: Thrust Without Fuel

08/05/2014 9:54 AM

http://www.newscientist.com/data/images/ns/av/shawyertheory.pdf

The first thing I see is that the side forces, Fs1 and Fs2, in fig 2.4 are vertical whereas the sides are not horizontal. It seems to me these forces should be perpendicular to the surfaces, in which case I believe the forces cancel and Conservation of Momentum lives to see another day.

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#24
In reply to #20

Re: Thrust Without Fuel

08/06/2014 5:58 PM

I have trouble reconciling the simplicity of the paper with NASA's results. The paper is at a 2nd or 3rd year college level; not particularly deep in terms of its Physics. It seems odd that the author tries to be rigorous with his math and graphs, but includes a very poorly drawn diagram that does not properly reflect (no pun intended) the ray traces of the microwaves.

Like this. The blue line shows the path when the correct angles are used for the reflections.

Yet, NASA claims they got positive results? Makes no sense.

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#25
In reply to #24

Re: Thrust Without Fuel

08/07/2014 10:05 AM

My understanding was that it was done in air because a HV power supply had an Electrolytic capacitor that was not certified for vacuum. Vacuum tests are being planned.

http://blogs.discovermagazine.com/outthere/2014/08/06/nasa-validate-imposible-space-drive-word/#.U-OFGPldWSo

It's a nice dream, turning energy into momentum. Lots of energy can be had from nuclear power, but due to the conservation of momentum, when a rocket engine runs out of stuff to throw out the back, that's all the momentum you're going to get.

I'm still betting on the Conservation of Momentum.

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#26
In reply to #25

Re: Thrust Without Fuel

08/07/2014 10:18 AM

Maybe they intend on gathering interplanetary particles [solar wind, dust, etc.] and accelerating them with this resonant cavity. Kind of a jet engine like approach but relying on the fact that space is close but not actually an ideal vacuum.

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#27
In reply to #26

Re: Thrust Without Fuel

08/09/2014 10:04 AM

Sort of like a Bussard Ramjet?

http://en.wikipedia.org/wiki/Bussard_ramjet

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#28
In reply to #26

Re: Thrust Without Fuel

08/09/2014 10:25 AM

This is another interesting idea for sailing the solar wind...

http://earthweb.ess.washington.edu/space/M2P2/

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#30
In reply to #25

Re: Thrust Without Fuel

08/10/2014 7:45 PM

I'm still betting on the Conservation of Momentum.

I like the way Physicist John Baez put it:
"this is about as plausible as powering a spaceship by having the crew push on it from the inside."

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#29
In reply to #24

Re: Thrust Without Fuel

08/10/2014 11:04 AM

NASA also claims AGW is alive and well

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#15

Re: Thrust Without Fuel

08/04/2014 11:01 PM

Whats this 30kN stuff? The article says between 30 and 50 micro-Newtons."

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#16
In reply to #15

Re: Thrust Without Fuel

08/04/2014 11:07 PM

Keep reading, the bizarre claims are in the second to last paragraph of the article.

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#21

Re: Thrust Without Fuel

08/05/2014 6:06 PM

Aye, it's that static thrust thingy. My garage floor exerts a static thrust of roughly 1 ton, and uses no power at all. If I wanted it to be warm so I wouldn't freeze my buns when I'm lying on it trying to run oil into my eye, I could embed some heaters, and then it might exert a ton of static thrust for 1200 W of power.

Mixing units of power and force is about as sensible as saying that the big rat snake who lives back of me kills two rodents a week, and has a laundry bill of less than $0.14 a year. In other words, if a claim don't make sense, grab your women, your liquor, and your money, and run away - he's after at least one of 'em.

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#22

Re: Thrust Without Fuel

08/05/2014 11:43 PM

My guess, once this has been thoroughly investigated, is that they'll find one end of the cone gets slightly warmer than the other end, causing the air to expand and push on the device. So heated air will be the actual cause of the thrust. (Note that even in the 'vacuum' chambers they used, there is still a trace amount of air.)

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#23

Re: Thrust Without Fuel

08/06/2014 7:28 AM

This thread is just making me a little twitchy.

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