Just a quick question. Are there any other methods of propulsin that come from electricity other than electromagnetic (like in motors), ion, or electrokinetic? None of them are incredibly effecient asfar as I know, except for those lego dacta motors. You hook up one motor to the other and spin one like a generator, the other will spin just about as fast. Close to 100% effeciency. Now how to make them bigger?
I've ran into that light craft site before. It got me wondering, could we make cars with giant convex lenses on the roof and focus the suns rays to a small enough point (inside some form of combustion chamber) to light propel a car down the high way.
Electrostatic, photon drive, and a few others. Lego motors are not even close to 100%. Do the numbers (torque*RPM) and I'd be surprised if it hit 70%. Bigger motors do a lot better, up to very high 90%s. Why?
-- Dirk The Consensus:-
Where are you getting your information? Well-designed practical electric motors can be better than 90% efficient. With superconducting wire and ball or roller bearings, nearly perfect. The inefficiency is in the techniques used to generate and store electricity, which is why water power is so popular - it doesn't have to be very efficient if the source is free and the infrastructure is cheap.
-- Full sun is 1000 watts per square meter, so for a 1 meter diameter lens that focussed spot would be home to about 785 watts. Not an
-- Except that the energy required to run the refrigeration equipment required to render the wire supercondunducting (or to make LN2) has
No. You can't make the image of the sun brighter than the surface of the sun. (theoretically, 1m from a 1m lens, you could get a 1cm spot, however, not much smaller.)
And the amount of energy you'd get would be horribly small.
No. But, that's with the sun overhead, or normal to the lens.
785W doesn't really go very far. compared to the typical energy budget of an automobile. Not to mention that 785W of heat will at optimistic best make maybe 300W of motive power.I read in sci.electronics.design that John Fields wrote (in ) about 'Is there any other way?', on Sat, 24 Sep 2005:
1.05 horse-power. So a 10 m diameter lens would be needed to provide 100 HP, about enough for a modern car.-- Regards, John Woodgate, OOO - Own Opinions Only. If everything has been designed, a god designed evolution by natural selection.
I read in sci.electronics.design that Ian Stirling wrote (in ) about 'Is there any other way?', on Sat, 24 Sep 2005:
No problem, just make it a 10 m diameter sphere, as in a sunshine recorder. (;-)
-- Regards, John Woodgate, OOO - Own Opinions Only. If everything has been designed, a god designed evolution by natural selection.
Be a bitch to find a parking space. :-)
Ed
That would look funny on the top of your Volvo.
John
In message , John Woodgate writes
A 1 acre field gathers sun energy over time and the horse yields the energy with low efficiency aided by the manual labour of one individual. Vast areas of land "over illuminated" could support panels with moisture conserved underneath for growing . Although by reciprocality It is not possible to focus a sun image with higher surface temp than the sun surface (a mirror) I believe it can be done if lenses of high refractive index are employed. Ignore demon email address.
-- dd
I read in sci.electronics.design that John Larkin wrote (in ) about 'Is there any other way?', on Sun, 25 Sep 2005:
It would look even funnier underneath it!
-- Regards, John Woodgate, OOO - Own Opinions Only. If everything has been designed, a god designed evolution by natural selection.
It wouldn't take much wind to put it there, either.
-- ? Michael A. Terrell
What, 6,000 C isn't enough? ;-)
Cheers! Rich
Youre going to have to check my math, but I once calculated the amount of power generated by one acre of sun light (based on contradictory information) and It came out to near 8 megawatts
Use electrolysis to split water into hydrogen and oxygen, and use them to power a rocket. Don Lancaster can fill in the details.
John
The figure I once memorized was about 1kW/m^2 incident light power on Earth. I don't know if that was with the sun in the zenith (where the light has to penetrate the least thickness of atmosphere).
That would come out as about 4MW/acre.
robert
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