airplane on a treadmill

[Doppelgänger]

Ummm...... stupidity is everywhere in here.

Any given wing design, in order to make enough lift, has to have a certain amount of airflow over it. So if this airplane is sitting on a treadmill, and the treadmill is moving with the equivilant of 100mph (planes wheels spinning at 100mph) but is remaining stationary, it will not lift. Now in order to make lift (and say something none of you idiots have said) the aforementioned aircraft would have to propell itself to whatever neseccary airspeed to create enough lift for flight. What seems also to be forgotten is that any given jet engine only creates so much thrust. If the treadmill is moving at 100mph, there will be a % of thrust needed to maintain momentium as gravity will try to pull the plane in the direction of the treadmill.

The reason the plane would slow down is because gravity pulling the jet down creates friction where the tire meets the ground causing the plane to slow down. Just like brakes dont stop a car. Brakes cause a weight shift toward the front of the car causing more friction on the front tires which slows the car down. Thats why you can have big ass raceing brakes and shitty tires and be out braked by a car with stock brakes and sticky tires. Same with the plane. Gravity will be pulling the plane "down" causing this same friction, which will in turn, cause the jet engines to be operating at a certain percentage, reqiring more thrust to exceed the stationary effect. The only way the plane would take off is if the "treadmill" was long enough for the plane to reach the appropriate AIRSPEED and if the engines had enough thrust left to propel them to the needed speed.

If you were to able to speed up the "treadmill" and the plane at the same rate until the planes propulsion system reaches 100%, the aircraft would NOT lift off. Remember, lift is a direct result of AIRSPEED (rate at which how fast air moves over the wings reguardless of thrust or ground speed). You "test is very poor because you are "propelling" the object yourself, rather then it doing it on its own.