Originally Posted by 95SiR
i think reading through the entire thread just confused me more. i kinda understand the argument behind the people that say "yes it will fly still" because of the thrust/jet engines not powering the wheels... BUT... the thrust created by the jet is what PUSHES the plane in a forward direction..and the wheels/tires are what allow the plane to roll and MOVE through the air. soooooo, although the wheels/tires are not directly powered by the jet like cars, the wheels/tires are what allow the plane to move to begin with, since in the beginning their entire weight is resting on these wheels/tires. the plane isnt hovering from the very start. 100% of the weight is resting on the wheels... and it needs to roll these wheels in order to physically move forward to create the needed lift under the wings.
as for the frictionless surface example like an iced lake surface or something. thats a good point, but not the same as the original question. on an iced surface, the plane still manages to take off because it still manages to move forward because the jet still pushes wheels/tires over the ice whether theres traction or not... basically the tires are just sliding over the surface. reason why i say this isnt exactly the same as the original question is because in the original question, this belt thing isnt stationary (like an ice bed) and it is hypothetically perfectly matching the exact speed as the wheel/tire speed so that the wheels/tires are also stationary in relevance to its starting point. on an ice bed, the wheels/tires are forced away from its starting point. but in the original question, it doesnt state that the jet engine overpowers this magical belt thing. therefore, as much thrust that the jet engine creates in order to force/push the plane through the air, because its weight is 100% completely resting on its wheels/tires, and these wheels/tires are not moving forward or backward in relative to its starting point, i still dont believe the plane will get to lift off.
the only way for air to "pass" or move over/under the wing is to have the plane physically move forward, but this magical belt thing supposedly matches the plane's forward movement perfectly and negates it.
so yeah. but if im wrong, oh well. too bad. then i guess its a good thing i dont get paid to make jet engines huh
h:
Wheels really have nothing to do with whether the plane flies or not. All they do is hold the plane off the ground, and have lower rolling resistance than say, a pile of bricks holding the plane off the ground.
We can look at this in terms of forces. I think all of us agree that if the plane can accelerate forward (ie net forward force) then the plane can eventually get off the ground. For a jet or propeller aircraft, the largest forward force is thrust from the engines, and that is there regardless of whether the ground moves or not. For drag forces there is drag from air as the plane increases speed. There is also a tractive force from the ground to the wheels.
Now, the tractive force from the ground to the wheels is the amount that is necessary to make the wheels spin. In the normal world, the wheel spins at a speed that is the same as the forward speed of the plane. In this fucked up conveyor belt world, the speed is faster than that of the plane's forward velocity since the conveyor belt moves backwards. But since the amount of force to spin the wheel twice as fast is not significantly higher, the plane is only slightly more slowed. Hence, there is a net forward force, and the plane will accelerate and take off.