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Really fun science/engineering/brainteaser video

Old 07-04-21, 02:52 PM
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tyrion
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Really fun science/engineering/brainteaser video

Can a wind powered vehicle go faster than the wind? Of course, sailboats and iceboats have been doing that for years.

But can a wind powered vehicle go faster than the wind, downwind?

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Old 07-06-21, 09:04 AM
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RubeRad
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Interesting, but what I don't get is, forward motion drives the wheels drives the propeller which pushes back and thus accelerates forward motion -- how is that not a circular dependency and a perpetual motion machine? And how does the wind actually factor into it? Does the tailwind somehow push that extremely aero-looking vehicle forward to start the chain reaction?
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Old 07-07-21, 05:03 AM
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Originally Posted by RubeRad View Post
Interesting, but what I don't get is, forward motion drives the wheels drives the propeller which pushes back and thus accelerates forward motion -- how is that not a circular dependency and a perpetual motion machine? And how does the wind actually factor into it? Does the tailwind somehow push that extremely aero-looking vehicle forward to start the chain reaction?
I watched it last week and didn't bother with the maths, but the fault in the reasoning towards perpetual motion seems to me that it used wind energy. I think the assumption that it only uses the energy of the wind corresponding to it's width is wrong. Through the efficiency and movement of it's aero blades it uses more of the surrounding wind than just the wind behind it by affecting it's flow.
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