Subject: Re: [extropy-chat] unidirectional thrust

From: Mike Lorrey <[email-masked]>
Date: Mon, 14 Mar 2005 17:00:31 -0800 (PST)

--- Keith Henson <[email-masked]> wrote:
> At 02:28 PM 11/03/05 -0800, Hal Finney wrote:
> 
> >Personally I'm a big fan of conservation of momentum.
> 
> snip
> 
> Me too.  Also conservation of energy.
> 
> And unidirectional thrust, if it is not velocity dependent (and
> reference 
> frames are supposed to all be the same) can be shown to violate the 
> conservation of energy by a simple thought experiment.

No, it doesn't. It neither violates conservation of energy or momentum.
To violate conservation of energy, you would need to show that the
amount of energy expended was in excess of the amount of kinetic energy
gained by the work done. This is not the case. Nor would it violate
conservation of momentum if it does tweak inertia through the
asymmetric field geometry and power pulsing. I think the harder thing
to believe is that inertia is caused by the gravity of all the other
mass in the universe when gravity is a speed of light phenomenon.

> 
> Just suspend the gadget at the end of a long arm in a vacuum, let it 
> accelerate to some arbitrary velocity such that you can lower a wheel
> with 
> a generator (or tap the hub of the suspension system) and make more
> power than it takes to generate the thrust.

Your false assumption is in thinking that I or anyone else is claiming
it does more work than it uses in energy. It is not an overunity
device, nobody but you ever claimed it was, and given this
misunderstanding, your opinion is suspect.

Mike Lorrey
Vice-Chair, 2nd District, Libertarian Party of NH
"Necessity is the plea for every infringement of human freedom.
It is the argument of tyrants; it is the creed of slaves."
                                      -William Pitt (1759-1806) 
Blog: http://intlib.blogspot.com

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---

From: Keith Henson <[email-masked]>
Date: Tue, 15 Mar 2005 09:46:47 -0500

At 05:00 PM 14/03/05 -0800, Mike Lorrey wrote:

snip

>misunderstanding, your opinion is suspect.

I don't hold any opinion so strongly that a good argument or better, 
experimental evidence, won't get me to change my mind.

I think something like this would be very cool, not to mention extremely 
useful.

I am not even welded to conservation of energy if anyone figures out how to 
get around it.

But if the device works as you indicate, how does it sense 
velocity?  Obviously you could get a lot more power out of a device going 
like a bat out of hell than one moving slowly.  So for higher velocities 
does it take more power to operate at constant thrust?  And in what 
reference frame?

Best wishes,

Keith Henson

---

From: Mike Lorrey <[email-masked]>
Date: Tue, 15 Mar 2005 20:11:43 -0800 (PST)

--- Hal Finney <[email-masked]> wrote:
> I thought Dirk was wrong at first, in fact I had a message all typed
> up, but then I thought.what if I'm wrong?  And then I decided that I
> *was* wrong! I think Dirk's analysis is correct. Let me make it more
> concrete.
> 
> Let's suppose a lifter will work in outer space.  We'll use a
> photovoltaic
> panel and some kind of DC-to-DC pulsed transformer to get the 30 kV
> we need.
> 
> Looking at the first chart on the lifter page at
> <http://jnaudin.free.fr/lifters/data/index.htm>, he can lift about
> 35 grams with Lifter v4.0, for 132.9 Watts.  That's a force of
> .035 kg times 9.8 m/s/s or about .3 Newtons.  A random solar panel,
>
<http://www.wholesalesolar.com/products.folder/module-folder/kyocera/KC167.html>,
> can generate 167 Watts and weighs 16 kg.  We'll add 4 kg for the
> transformer (this is all hand-wavey) and get a 20 kg device that we
> can shoot into space and it will start accelerating all by itself.
> .3 Newtons over 20 kg is about .015 m/s/s acceleration that our
> device will deliver. It's small, but it builds up. After 1 day, it's
> going over a kilometer per second! And velocity increases by a km/s
> every day. Meanwhile we are putting in 132.9 Watts the whole time,
> which is 132.9 J/s times 86400 s/day or 11.5 MJ per day. Well, after
> two days we are at 2 km/s so our kinetic energy is m*v*v/2 or 40
> MJ. But we've only used 2 * 11.5 MJ or 23 MJ. So Dirk is right, we
> are over unity already, even with a primitive lifter like Naudin
> has designed.  And it gets worse every day.

The error you start off with is that you are using the thrust it
demonstrates at atmospheric pressure, using atmosphere as the
dielectric medium. Try first adjusting the thrust to that predicted by
the dielectric value for vacuum. Fix that error and you wind up well
within the realm of mundane sub-unity efficiency.... lets try again.

Mike Lorrey

---

From: Keith Henson <[email-masked]>
Date: Wed, 16 Mar 2005 09:01:54 -0500

>within the realm of mundane sub-unity efficiency.... lets try again.

Mike, it doesn't matter how small the thrust is, unless the thrust declines 
in a specific way with velocity, any such drive will go over unity eventually.

Mind you, I *wish* such a thing existed and would be delighted if it 
did.  But energy to thrust doesn't work--another way to put it is "wrong 
units."

Unfortunately.

Keith Henson