Airplane-treadmill problem from boingboing

Pete

This goes in general chat because the discussion needs to take place.

If you put an airplane on a giant treadmill, and the treadmill is designed to go exactly the same speed as the wheels, will it take off?

I say No. same as the NYT. For some god only knows reason, boingboing say Yes, with an explanation which doesn't make sense.

I will emphasise "designed to go exactly".

tosscat

Of course not.

David

According to [Andy's NASA lesson for Liz](http://www.stroudgreen.org/comments.php?DiscussionID=331&CommentID=1979) the four elements for a plane to fly are Lift, Weight, Thrust & Drag. Weight and Thrust would still be ok, weight of plane, engines going. Lift is attained by the aerodynamics of air passing over the plane and Drag is generated against the plane when in motion. So these two elements would not occur. So no, of course not twice.

Pete

Exactly, no need for a poll here.

What I think has happened on boingboing is that the blogger misread the problem. For the threadmill to match the wheel speed, that means it would have to be powered to match the thrust, otherwise, its just a slipmap on a runway.

The other thing he could have misunderstood is that the threadmill could be working WITH the thrust, like a slingshot. This would work, I think; they use it on aircraft carriers.

Would possibily save on fuel as it could be powered through other means. Could be considered greener than burning fuel to reach speed. Hybrid planes?

David

We could just make big human sized slingshots and launch ourselves over to Europe in seconds. Just not sure about the landing bit.

Pete

Parachutes.

Or Squirrel suits. Fly half way there. Zero emissions. Hell, you could just hire people to turn the spring for launch

Pete

more people talk bollocks on boingboing.

Can someone talk about Lift and airflow with them? I starting to lose respect for them