Friday, February 1, 2008

Plane on a Conveyor Belt

This has been covered in many places, most recently live-blogged by Kottke as it was proven on Mythbusters. Google "plane+conveyor" and you get 485,000 results. For anyone who somehow missed this, there has been an impossibly huge argument about whether a plane on a conveyor belt could take off. Most people who argued that it couldn't mistakenly thought that a conveyor belt running the opposite direction of the airplane would somehow make the plane remain stationary with its wheels spinning, when in fact the wheels have nothing to do with how a plane propels itself. Taking off, the plane would act exactly the same as under normal circumstances but with its wheels spinning twice as fast. Enough. 
 
I think a better question might be: can an airplane take off in a wind-tunnel (though obviously a big tunnel with a very high roof) without moving forward?

6 comments:

Kitey Kiterson said...

Wouldn't that just be like a giant kite? I vote yes, it would work (albeit maybe only in theory, dunno how the mythbusters gang could prove it, unless they shrank everything down in scale).

Charlie said...

maybe a giant and very heavy steel kite... i figure the air would act upon the wings the same way as if it were going forward, creating lift, but that the plane would probably just flip over and blow up. maybe if it were tethered to something to keep the wind from actually pushing it backwards/flipping over/exploding...

Kitey said...

Would definitely need the kite string, otherwise it would surely just blow up, over or around. Be neat to see though.

springy sprung said...

See, the point of having a plane is that it isn't a kite. Sure a tethered plane would takeoff- but a tethered almost anything would take off.
I think that it would be possible to generate lift using only the fans of the wind tunnel (what ever take off speed would be) and to use the engines of the plane to keep it more or less in place.

Charlie said...

Hmmm... if the now tethered plane could in fact lift off and get its engines firing at several hundred kph, could the fans be turned off and tether cut to allow the plane to take off without a runway? Would it go from 0-250 almost instantaneously or do more crashing and exploding?

fallguy said...

ok, it lifts off like a kite, but as soon as the air is shut off it falls, no matter how fast the engines are going. if there is nothing moving under (and over) the wings, the plane falls. if its high enough off the ground it can get moving fast enough to correct for this and take off, otherwise it falls to the ground