Plane on a treadmill .. to be on Mythbusters

[kn]

KruzeS said:

kn said:
You guys seem to all be assuming zero friction between tire and wheel. There is friction. If you were able to somehow feather the throttle up slowly while increasing the treadmill speed, the friction of the wheels of the plane on the treadmill will exert a rearward force which could easily be countered by an increase in throttle.

Yes, there is friction. But the rolling friction from the wheels is negligible - at take off speads, the air friction alone is already a much bigger factor.

A plane that can propell itself forward from a stationary position (beating inertia, rolling, driveline and air frictions), and accelerate itself to take off speeds just by moving air, cannot and will not be stopped by a threadmill.

 I can assure you that there is some speed at which a spinning treadmill can offset a *small* amount of thrust from the plane due to friction.  They are saying takeoff speed which is about 60-65 mph for a smallish craft.  A treadmill running at that speed against the landing gear will most certainly produce enough rolling resistance to require some thrust from the engine to counter the rearward "pull" from friction.  I certainly won't be much thrust, however, and again, regardless, there is no lift from airflow.

An interesting thing to note with coefficient of drag as it pertains to rolling resistance is that the softer the two surfaces, the more rolling resistance there is.  Steel on steel would, of course, be very little.  Rubber on Concrete a bit more.  Rubber wheels on a treadmill which will also be a "softish' surface or at least deform to some degree, will provide a bit more resistance.

However...

I think as one poster has said above -- we are misunderstanding the intent of the "myth" becase this one is so obviously impossible.