I don't understand the question, the treadmill always matches the speed of the plane in what sense? Anyway i googled and found
this which seems a good explanation.
If you stood on a treadmill and someone pulled you with a rope, they'd be able to pull you off the treadmill, similarly if you were on an icy pond you may not be able to 'pull' yourself off the pond because you kept slipping, but someone throwing you a rope would be able to pull you off the pond.
The force being used is 'external' to where the 'frictionless' environment is. The engines on a plane are the rope, they don't 'use' friction with the ground.
On a long enough treadmill the plane would be able to takeoff, just as a plane is able to takeoff from antarctic/artic environments that have 'ice runways' which is what i think the question may be alluding to with the 'treadmill matching the speed of the plane' bit, ie frictionless environment.
Quote:
|
Originally Posted by dda
There is a reason why airports have runways facing in different directions and swithch the airplanes around so that, as far as practical, airplanes take off and land heading into the wind.
|
They haven't built major airports in that manner for half a century!! Runways are now routinely built parallel to each other, like the two existing ones and planned third at
heathrow. Jet airliners offset their landing gear when landing in
cross winds