[EricH]

Originally Posted by Molten

Don't you see the problem in this debate? It is the "experiment conditions". The way many of you are reading it, it suggests that the plane can move just because the wheels don't give any propulsion. The way that I am reading it, the plane can't move(relative to the air) period. That is what is critical here. It is not that they can't take off if the plane can move relative to the air. In fact, with the conditions that you specify I agree, It could take off. The point I disagree with you is the conditions that you interpret from the original statement.

The original post:
"A plane is standing on a runway that can move (some sort of band conveyer). The plane moves in one direction, while the conveyer moves in the opposite direction. This conveyer has a control system that tracks the plane speed and tunes the speed of the conveyer to be exactly the same (but in the opposite direction).

The question is:

Will the plane take off or not? Will it be able to run up and take off?"

The formula:

The vest way to track the speed of the plane would be to find the
C=circumference of the wheels
R=# of rotations of the wheel
T=time the wheel takes to rotate that # of times
S=Speed of plane=Speed of conveyer belt

S=(C X R)/T

Now, let's take this one step at a time. The plane is stopped. The conveyer belt is stopped. The plane starts to move and the conveyer belt INSTANTANEOUSLY starts to move in the opposite direction. (remember this is all in theory with ideal conditions) As the plane speeds up to the speed necessary to take off, the conveyer belt does the same in the opposite direction. Now, with these conditions, it is impossible.

To truly put this to rest, the conditions would have to be more clearly stated in the question. For instance, how does it track the planes speed? That is rather critical. Do we ignore friction? As some have posted in the past, what about wear and tear? I think that interpretation is the true decider on this one. I am positive that with the conditions in my mind, I am right. I am positive that with the conditions in your head, you are right. The thing is that the conditions were not clearly stated to the original post and thus we have no choice to say that either outcome is possible depending on how it is interpreted.

P.S. I hope that if you do not understand my statement on the interpretation of the problem, then we can just agree to disagree.

Also, sorry for the long post.

I'm sorry, but I still do not understand. You haven't done any work to prove the equation. Under the experiment conditions, I could probably get at least an R/C aircraft off the ground. The only condition is that the conveyor is moving at the airplane's speed in the other direction. And the fact of the matter is, an airplane's wheels give NO propulsion. (If you want to argue this point, come on over to SDSMT, and I will take you into the CAMP area to where the Aero Design team is and show you on R/C aircraft. Or, find your local model-aircraft store.) The only factors here are friction and thrust. Friction of the wheels--probably negligible. Thrust of the motor/engine--plenty to overcome friction.