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Wind Tunnel Launcher

not the treadmill
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I'm sure you came across the idea of launching a plane off a treadmill, which won't work because lift of a plane depends on air flowing over the wings, not the speed of the wheels. But instead have fans blowing on the wings strong enough to lift the plane. With the engine running, it will take off with no need for a runway.
the great unknown, Nov 10 2008

(?) BustMythted http://video.google...e&hl=en&emb=0&aq=f#
[2 fries shy of a happy meal, Nov 10 2008]

[link]






       //But instead have fans blowing on the wings strong enough to lift the plane.// or put these fans on the wings of the plane.   

       It is interesting that you use the word "plane". As this is the only place your idea will work. Unless you have a 100 storey building of fans....   

       This means you "runway" is less horizontal and more diagonal.
4whom, Nov 10 2008
  

       //launching a plane off a treadmill, which won't work //   

       um... link.   

       So the aeroplane takes off, not unlike a kite. Then what? Hint: what happens when an aeroplane finds itself stationary in stationary air?
Texticle, Nov 10 2008
  

       gravity.
Custardguts, Nov 10 2008
  

       Wow, all those years spent developing catapult launchers for aircraft carriers, and JATO units .... and all it needed was a few fans .....
8th of 7, Nov 10 2008
  

       The friction between the treadmill and the tire counteracts the force of the thrust from the propeller, however the air is being pushed over the wings with an altered flow field due to a temperature and pressure dependent treadmill boundary layer (which acts as a flat plate moving through a viscous gas or fluid at rest relative to the ground).   

       I thought you were going to say "put a paper airplane on a treadmill, set to 10 speed, and then launch her like a catapult". Still, you could also run the treadmill in reverse and move the plane twice as fast through the air assuming the wings are high enough above the air boundary layer of the treadmill.   

       That sort of reminds me of one time I was on the beach, and there must have been 20 mph winds, I saw this seagull struggling going as fast as it could against the wind and it was only hovering in one place above or relative to the ground.
quantum_flux, Nov 11 2008
  
      
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