Quote Originally Posted by 2manymustangs View Post
THRUST is going to move the plane foward (either jet or SCREWING ITSELF through the air)... I'm just trying to find out how fast you have the plane going backwards on the pretend treadmill... I wanna know how long (not IF but WHEN) it will take me to lift off as soon as I start making thrust, without any thrust the wheels are glued to the treadmill belt just like the aero-plane is and she is going backwards...
Let's say for the sake of argument, that the engines on a jet propel it forward at 800 miles per hour (I have no idea how fast they really go, but bear with me here). Now imagine that the plane is sitting on a really long conveyor belt. Both the belt and the plane are stationary, and the jet engines are off. Now, imagine that the conveyor belt starts moving at 800 mph. Seeing that the plane's engines are off, the plane gets dragged backward at 800 mph by the belt.

Now, if the pilot fires up those engines, that 800 mph of force is only going to counteract the backwards-moving conveyor belt, right? 800 mph in one direction less 800 mph in the other direction equals 0 mph. So, the plane sits stationary as the conveyor belt goes by beneath it.

If the plane isn't moving, then the air isn't moving above and beneath the wing at the required 800 mph, thus creating no lift. And that's that.