Tuesday, December 12, 2006

Boing Boing: Airplane-Treadmill problem

Boing Boing: Airplane-Treadmill problem

Surely - and I may be wrong - planes derive their lift from the bernouille effect of air moving very fast over the aerofoil of their wings. As the plane would not be moving forward in space, there would be no airflow over the wings - the point of runways is to get sufficient speed of airflow to produce enough lift to let the plane take off.

What you have here, is a jet powered thing revolver?

3 comments:

Anonymous said...

That's my understanding, it doesn't matter at what rate the wheels of the aircraft revolve at, it's the speed the wing has through the air that counts to create the lift.

Anonymous said...

That's my understanding, it doesn't matter at what rate the wheels of the aircraft revolve at, it's the speed the wing has through the air that counts to create the lift.

Joanna said...

But the wheels have no drive themselves. If the plane was driven along the ground via the wheels like a regular car then the treadmill would counteract the movement of the wheels.

The wheels are just there to reduce friction to allow the plane to move down the runway - look at other planes such as seaplanes and snowplanes that do not use wheels and have skids instead.

The forward motion is provided by the jet engines, not the wheel, so the treadmill has no effect.

If you countered the jets by chaining the plane to the ground then the plane would not move forwards, and as you rightly say there would be no lift due to the wings moving through the air.