RE: 747 on a treadmill conundrum..
September 5, 2014 at 8:58 pm
(This post was last modified: September 5, 2014 at 9:06 pm by Anomalocaris.)
(September 5, 2014 at 5:19 pm)lifesagift Wrote: Surely you guys have seen this before?
"Imagine a 747 is sitting on a conveyor belt, as wide and long as a runway. The conveyor belt is designed to exactly match the speed of the wheels, moving in the opposite direction. Can the plane take off?"
This is a forum norm, and I'm still not convinced either way !
Depends on whether the plane turns on its engines. If it does, then yes, it can. If it does not, the no, it can't. The engines of an airplane is a reaction engine. It doesn't work by pushing against the ground, or even the air. It works by shoving large mass of air backwards. If you throttle up 747's engines up to full power, the thrust of the engine will power the plane forward no matter what the wheels and the treadmill is doing. The wheel can spin twice as fast than it normally would to accommodate the treadmill, or not. If not, it will drag the wheels across the treadmill. The friction of the tires will not hold the 747 against the full thrust of its engines.
