EmDrive + Focus Fusion = Space Access for all?

[Sigma]

I’m not sure many of you have heard about a recent technology called the Em-Drive, but it is the first “propellant-less” space/terrestrial drive developed. Thus far it has only been able to create around 2g of thrust, but the designer believes further iterations will be able to up that to tonnes of force via superconductors and niobium. It uses a magnetron connected to a specially shaped resonant cavity, the difference in wave velocity with it being higher on one side, creates measurable net force on its surroundings. The inventor believes that the technology will allow for both outer-space and earthbound vehicles to be developed.

http://news.uk.msn.com/Article.aspx?cp-documentid=877900
http://www.theengineer.co.uk/Articles/Article.aspx?liArticleID=295931
http://www.theengineer.co.uk/Articles/266633/Defying%20gravity.htm
http://www.emdrive.com/

My thought was that it would be a perfect fit with the Focus Fusion reactor(when it is developed of course), this would allow easy access to space and fast transit to neighboring planets, while only having to refuel occasionally.

[Glenn Millam]

I’d like to see what Eric Lerner has to say about this… it sounds really cool. Focus fusion is partially supported by JPL, and, before spending cuts, by NASA as a potential breakthrough spacecraft propulsion technology. There is an article somewhere on the site about it. It would be great if the emdrive could be coupled to a PFF reactor. I just wonder if the emdrive would be a better solution, given what the FF can do on its own.

[Elling]

The space industry is impressive for its engineering, maybe not so much for it’s science. For climate control we would need large solar sails to adjust the solar constant over the surface of the Earth. Specific g performance may not be the parameter in demand rather total low payload and the thrust to pull the sails’ shadow into position over the poles fex

[Jolly Roger]

A copy of the EM Drive theory paper is now available to be downloaded in pdf format at the New Scientist website http://tinyurl.com/npxv8

[PlanetStorm]

Jolly Roger wrote: A copy of the EM Drive theory paper is now available to be downloaded in pdf format at the New Scientist website http://tinyurl.com/npxv8

The paper looks very flawed to me. The forces on the end-walls of the cavity seem to be correctly calculated (and, of course, there is a mismatch which provides the motive force this system is supposed to provide). However, the longitudinal component of the force on the cavity imparted by reflections from the tapered walls seems to be entirely omitted. I believe that these forces sum up to exactly cancel the mismatch calculated just from including the ends of the cavity. This is a similar mistake to assuming that if the cavity where filled with a perssurized gas, the gas would exert more force on the larger end than on the smaller end and so provide a resultant force on the cavity towards the larger end. This doesn’t happen because the pressure of the gas on the tapered wall exerts a resultant force towards the narrower end, exactly cancelling the effect.

I believe that the author also makes an error in calculating the limiting velocity. The problem is a relativistic one and therefore the solution has to be frame independent. This means that the limiting velocity has to be quoted relative to something, but the author only refers to a stationary system. In any system operating in free space with no external forces, any thrust has to be frame independent, which means that the only limiting speed (to an external observer) is the speed of light itself, although someone sitting inside the cavity would continue to feel exactly the same acceleration for however long energy continues to be put into the system.

[vansig]

as you may recall, end of july 2014 NASA presented some test results from this, which i’ll link here…

http://www.libertariannews.org/wp-content/uploads/2014/07/AnomalousThrustProductionFromanRFTestDevice-BradyEtAl.pdf

[delt0r]

It is very flawed. The paper is just a mess and wrong (they leave out forces). The experiment was also flawed to the point of credibility of those involved. You can’t measure that sort of force without a vacuum. Also the control also produced a force. So the experiment didn’t prove anything.

[vansig]

the control produced a force about a magnitude lower, due to electric currents i think. they subtracted that from their tests

[delt0r]

Why doesn’t anyone read the dam thing. No they reported the same force. Since the only force they measured was only twice what the force meter could measure there isn’t any force measured at an order of magnitude less.

Also the force was so small that it is just not credible with an atmosphere.

It is very sloppy experimental work at the very least, and not even close to extraordinary evidence required by the claims. The original claims and theory may as well be a free energy youtube video with just how bad they get it wrong.

[vansig]

do not confuse the Cannae null test article with a control. it was a test article that Cannae had not expected to produce thrust, yet it did.
for that, Eagleworks has merely shown that Cannae’s theory was false.

i’m talking about how Eagleworks removes the 9.6 uN, that is part of the test apparatus, from each the tests to find ~95 uN or so net force.

“The (net) peak thrust observed for this tested configuration was 116 micronewtons and the (net) mean thrust over the five runs was 91.2 micronewtons. The net force is calculated by accounting for the null force present in the system. Null testing is performed by attaching the RF drive system to a 50 ohm load and running the system at full power. The null force testing indicated that there was an average null force of 9.6 micronewtons present in the as tested configuration. The presence of this null force was a result of the DC power current of 5.6 amps running in the power cable to the RF amplifier from the liquid metal contacts. This current causes the power cable to generate a magnetic field that interacts with the torsion pendulum magnetic damper system. The null test data is also shown in Fig. 20.”

[Andrew Palfreyman]

There exists a generic problem with all propellantless schemes, and that is violation of both momentum and energy conservation. This leads to the generally true statement that if you can build a propellantless thruster, then you can generate free energy continuously, forever. Mathematically, all that’s required is to define a relationship between power input and thrust (you can pick linear or anything else you like). Then write down the energy budget for acceleration in free space, and compare kinetic energy to total input energy. You’ll find there’s a breakeven velocity (or equivalently distance or time), above which the kinetic energy exceeds the total input energy. So not only is a propellantless drive great for space travel, it solves all our energy problems too!

[vansig]

Andrew,
that’s wrong. No one who looks into this a bit more deeply is saying it generates thrust without cost.
Shawyer is saying that the cost is reduction of the Q of the resonant cavity, and that consumes energy
while heating the cavity.

If you try to build a perpetual motion machine with this, you will fail.

Paul March speaks of mass transients in this interview
https://www.youtube.com/watch?v=SmAbmCuO5tE

imagine, if you would, since we know that there is considerably more mass in our galaxy than
we can see, and we call this “dark matter”, that there is some way to interact with this dark
matter whereas ordinarily it passes through regular matter.

and isnt the carrier of the electroweak force is just such a particle? it can interact with
electromagnetism.

so hypothetically, we should be open minded about this notion of mass transients.

[Andrew Palfreyman]

vansig,

Feel free to be open-minded. I worked with Paul March and Jim Woodward for 15 years. I have a degree in physics from Oxford. I don’t make assertions lightly.

I already gave you a simple recipe for a high school (UK: grammar school) algebraic derivation of my assertion that all propellantless propulsion schemes are inherently OU.
It is up to you to turn the crank.

As for dark matter – I believe you forgot to throw in the kitchen sink, too.

Andrew Palfreyman

[vansig]

Good, then. please tell us about this, “globally conservation is theorised to obtain via the proposed Wheeler-Feynman transactional mechanism.” — http://physics.stackexchange.com/questions/5471/is-the-woodward-effect-real/46377#46377

[Andrew Palfreyman]

Only if you can demonstrate that you’ve invested the skull sweat to understand the assertion that all propellantless propulsion schemes are inherently OU. I’ve shown you how to do it. Show us that you get it.

[Author]

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