I think I've got it straight.

[desmo_drum]

Don't hesitate to throw eggs but

O.K., I think I got this straight in my head. The only forward thrust needed by the airplane engine would be to overcome the rolling resistance of the wheels on the conveyor. The same amount of thrust (or very close) to actually just producing movement of the airplane forward on the ground. The convyor can move as fast as it wants to but because it is only acting on the wheels, it is transmitting very little backward resistance on the airplane, therefore there would be very little thrust needed to keep the airplane in a stationary position. If more thrust is applied the airplane would move forward on the conveyor and eventually get aloft if the conveyor was long enough (wheels spinning speed = Takeoff speed + conveyor speed). If the amount of thrust was applied to only keep the plane stationary, the amount of thrust would be barely off idle, so the plane would not take off as the engines could not be applied with full force because that would cause the plane to easily overcome the forces of the wheels and move forward.

The scenareo implied that the more thrust can be compensated for by the speed of the conveyor. It cannot. If the airplane were using skids instead of wheels, a little more thrust would be needed to overcome the friction, but again, its would be the same amount of thrust needed to barely move the plane on non moving ground.

CONCLUSION: The airplane has to be moving to take off. On a long moving conveyor, that is no problem because of the minimal thrust needed to overcome the friction of the wheels and move forward. If the plane is to remain stationary, It is impossible to have the plane remain still and apply more than just a minimal amount of thrust. Therefore not enough thrust and no forward movement means it stays on the ground. The full throttle with speeding conveyor is not physically possible.

Please lock if desired.

[bobspapa]

go run on a treadmill with a kite

[AKmnstr]

Dah????????

So you see, I ride a motorcycle and it doesn't run on a treadmill. I also try to keep it on the ground most of the time.

[ducatania]

Have you guys never heard of Bernoulli's Principle? It's the flow of air <i>under</i> the wings that makes the plane fly. If a plane is on a conveyor and is stationary, no matter how fast the wheels are going, if there's not sufficient airflow under the wing, it's not going anywhere.

[Monsters Inc.]

This has got to be f'n joke. :

[the_journeyman]

Yes, but airplanes are unique to other wheeled vehicles that the wheels do not produce any propulsion. They simply keep the aircraft off the pavement. The propeller/jet creates the thrust. IMO, if the conveyor belt was albe to react quick enough to cause the aircraft from gain ANY ground speed, it wouldn't take off.

Part of me thinks that the fact the airplane does not rely on a force acting on the ground it will speed up and the wheels will be going 2x the measured ground speed of the airplane and it will still take off ~

JM

[desmo_drum]

O.K. I don't want to torture anyone else.