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drag
drag is offline
#6
Feb1-04, 06:38 AM
Sci Advisor
P: 1,341
Greetings !
Originally posted by jjalexand
If a vehicle could continuously cool the air in front of it and heat the air behind it, the air in front should contract and the air behind expand, reducing the pressure in front of the vehilce and increasing it behind the vehicle. This should pull the vehicle into the cooler air at the front, and push the vehicle away from the hot air at the back, propelling the vehicle through the atmosphere without moving parts or any additional propulsion. (Let's assume for the moment a helium balloon type object, that just floats at a certain height, for simplicity).
Such an aircraft would not be able to achive high
velocities and would use up lots of energy.
Basicly, a hot air baloon or an airship do the
same thing, but the airship requires no power source
and the hot air baloon is more efficient than something
like the above is likely to be.

As for the skin idea, I really don't have a clue about anything
like that. I do know that there were and are experiments that
attempt the use of a pimpled - kin'na like a golf ball's, surfaces
that, supposedly, reduce drag. I'm not sure though weather its
applicable for all velocities - subsonic and supersonic and how
long it'll take for us to see flying golf balls, but it
seems promising. [;)]

Live long and prosper.