[Cole]

Originally Posted by MuseChaser

I've always liked that question. Unfortunately, it's based on fallacious logic. The wheels on an airplane, unlike a wheel-driven vehicle (engine-to-transmission-to-differential-to-axle-to-wheel or similar) are not driven at all; they just idle or "coast" like the wheels on a shopping cart. An airplane-sized treadmill would have no effect on the speed of the aircraft; the aircraft's speed (caution--- oversimplification ahead) is governed by the thrust of the air rearward by the propellor. The aircraft would move forward independent of the speed of the treadmill. As the airspeed increases, the wheels would spin proportionally faster than the treadmill until the airplane would eventually lift off in the same amount of horizontal distance it would have lifted off if the ground beneath it had been stationary; it's airspeed across the wing that determines the lift. Now, if the treadmill/wheel interface creates an appreciable amount of drag, then it would take longer to achieve the required airspeed for take off, but there's no way a treadmill COULD "match the wheel speed... so that no forward motion is achieved" simply because the wheel speed would have no effect (other than friction of the wheel to treadmill interface and bearings) on forward motion. That plane is going forward, no matter what, unless the wheels are being prevented from rotating by brakes or wheel chocks.

Soo... fun question, but faulty premise.

Yeah, there's a bit more to it, but that's the gist of it.

Barry

Yes, but we're talking entirely theoretical here. If there's no air moving over and under the wings, no lift can be generated. Like if you're on a treadmill that's matching your speed exactly and you're wearing a parachute. Is that parachute going to fill up with air?