Originally Posted by TheKentishFledgling
If the aeroplane is not moving THROUGH THE AIR it cannot fly. If it's on a conveyor belt, the belt doesn't care what speed the air is moving and the belt won't move the air to move (OK, it could be argued that the "boundry layer" of air to the belt has a velocity, but realistically it's enough to ignore in this case).
All the time the belt is moving "backwards" at the same speed the a/c wing is moving forwards, nothing will happpen.
Think of yourself running on a treadmill (unpleasent thought, I know...!)....when "running" at the same speed as the belt, you are stationary - your relative wind = 0, therefore no angle of attack, therefore no lift.
Good one though, has got me thinking about how to word an answer.
tKF
Well, yes. That was my original thought when I posted this thread. However, in reading some of the arguments on the original site, I am now convinced that the aircraft will fly.
The basic argument says that since the wheels of the aircraft are free to rotate (i.e. not powered like a car) the movement of the conveyor belt will do nothing except cause the wheels to rotate. Assuming no friction, the aircraft will remain stationary. Now... start its engine, and it will pull itself forward through the air until it gains sufficient speed to take off. The difference between this and a similar question involving a car is that a car powers itself by pushing against the ground, while an aeroplane powers itself by pushing against the air.
TPK
