Originally posted by: LoKe
Then can someone explain this to me real quick? I don't feel like digging in the other thread :
If the plane and conveyor are moving at the exact same speed, meaning, the plane isn't moving, is air still being moved?
Long story short: There are two interpretations to the control system discussed in that thread. The first interpretation is that as the plane moves forward at a velocity V (with regard to the stationary ground), the conveyor will move backwards at a velocity -V (with regard to the stationary ground). However, since the movement of the conveyor has a minimal effect on the movement of the plane, the plane will accelerate to takeoff speed Vto, with the wheels spinning at 2*Vto thanks to the conveyor matching that speed in reverse.
The second interpretation is that the conveyor will match the "ground speed" of the plane on the conveyor, in other words, if we hooked a speedometer to the plane's wheels, it would read that and match it in the other direction. This control system is impossible, because if the plane accelerates to any velocity V (even if it's really, really tiny), the conveyor needs to speed up to Vco=Vco+V. This leads to the conveyor going infinitely fast, even if the plane is only moving at 1MPH.
Facebook
Twitter