I got a question for ya.

[BurkeWorld]

Question:

An airplane is sitting on a runway. This runway is slightly different though, it can move. Lets say the plane turns it engines on and starts driving on it's landing gear. But as the wheels turn, the runway moves in the opposite direction so the plane remains stationary, but it's wheels are rotating anyways. Got that? Now, if the speed gets great enough, and the engine are blasted, but the plane isn't moving forward, will it still take off?

Yes or no, explain your answer.

Burkey

[felineki]

Well, physics isn't my strong point... but from what I understand, planes get lift due to the way the shape of the wings guides the air flow across them. If the plane's not actually going anywhere, then there's no air moving across the wings and thus no lift. So I'm gonna say it wouldn't take off.

[Daisensei]

Felineki would be right if the air isn't been carried by the runaway. I'm not remember well, I had my last Physics lessons 20 years ago, but this depends on the viscosity of air and the friction with runaway surface. Ahhhg! Burkey, you give me a headache! 

[Mechadon]

The wing has to be moving forward in order to lift. Flying has nothing to do with the wheels.

[Blackcat]

It will take off for two seconds, then collide or crash with something…

[Takila]

If we aren’t told about the ambient conditions (Wind, floods, comets, etc.), then either way can be argued either way.

EDIT: Gravity stops (Between the plane and the earth), allowing the plane to drift away.  Gravity promply re-applies itself in a flurry of appologies and excuses, allowing for the pilot to pull the plane out of a screaming dive and back into the air.  And then it explodes.
So... maybe.

[Supersonic]

Firstly, no power is ever applied to the landing gear (other than braking power during landing)...it's all done through the propellers on the nose or wings of the plane. (Or the jets, if you're into that sort of thing)

So it is very unlikely that a conveyor belt, no matter how fast, would be able to stop the plane itself, since the wheels are in neutral. The wheels would just rotate clockwise to match the action of the belt.

However, disregarding the laws of physics previously mentioned, the laws of physics dictate that a plane cannot takeoff without that forward motion creating lift.

[Methid Man]

Not unless you give the plane some air.

-- Sam the Methid Man

[Violet]

No, but if the runway itself is being moved (not just turning in place), it could help.  The only way this can be done would be an aircraft carrier.

[NPC]

You guys are forgetting about time warps and black holes.

These things can make all the difference.

Like, duh.

[Takila]

It could be a harrier jet...

[klarthailerion]

A Navy airman I used to work with explained this one to me before, but the qualifications in his question dealing with the speed of the conveyor belt, the plane, and the wheels on the landing gear were a little more specific.  The gist of it, though, is that the plane will take off.

The wheels on the landing gear spin as a result of an applied force, but their spin is largely independent from the movement of the airplane itself.  The airplane will take off as a result of lift on the wings, which will require forward movement. 

If the conveyor-belt runway is moving backwards with the airplane's engines at rest, that force will not be completely applied to the airplane itself because the friction resulting from gravity (a downward force) will offset some (but not all) of the force of backwards-movement resulting from the movement of the conveyor belt.  Some of that momentum will be transfered to the airplane through the wheels on the landing gear because of friction. 

If the conveyor-belt runway is at rest and the airplane's engines are moving the airplane forward, that force will be completely applied to the airplane itself because the engines are fixed to the wings of the plane.  There will be some loss of potential momentum because of friction on the landing gear, but not nearly enough to equal the friction caused by the backwards-moving conveyor-belt runway.

So, when the engines are fired to accelerate the plane forward at the same rate that the runway is moving backwards, the body of the airplane itself will be given forward momentum and will eventually reach a great enough speed to achieve lift (at which point in time it would accelerate much more quickly).  This is all assuming that conditions exist with the rate of gravity, the surface of the runway, and the wheels on the landing gear do not create excessive friction that prevents the landing gear mechanism from operating properly, thus preventing the wheels from being able to spin.

His explanation was a lot simpler and more concise, but that's the gist of it.  The force transferred to the body of the airplane is greater from the engines than from the runway because the wheels are free spinning and do not transfer the full amount of force from the runway to the body of the plane.  Hope that made sense.

[Daisensei]

Suppose an initial state which the airplane are placed on a conveyor belt, both in rest relative to the land, and that the wind is negligible. The length of the belt must be very long, so the airplane length will be neglected; and the belt width is at least the same as the length of both wings. Nothing is moving, thus the rising force  is null. Further assumptions is that the wheels of the airplane are perfectly circular, and that the surface of the belt is smooth; both aren't deformed regardless the forces applied on them.

Now, suppose that the speed of conveyor belt is being increased in not so fast rate, when the plane motor is adjusted to move it with the modulus of velocity exactly equal to of the belt, but in the opposite direction. Nothing seems to happen, except for the wheels and belt motion. However air is moving too, due to the friction with the belt surface (and remember, it was assumed that the belt is very long). Under such conditions, being a fluid, the air will flux in different speeds being more faster when nearer to the surface. Increasing more and more speed on the conveyor belt, the air speed augments too; the air when are trespassed by the wings provides an uprising force, and the airplane will lose its weight. Eventually when this force overcomes the weight, it can fly; however in a great speed the air flux can change from the laminar motion for turbulent motion.

I´m not sure what can happen in turbulent motion of the air, but it's likely the airplane will be thrown away as it was hit by an hurricane. Nevertheless, assuming that the plane is still there, and the speed is further increased, eventually it can reach the sound velocity (Mach 1). I'm guessing now, but aside the wheels being quickly burned by the friction, an explosive wave of air must blown out our poor airship beyond this stage.
Furthermore, taking a very unlikely assumption that the plane still resisted all of that, one can increase speed more and more. When the belt and the wheels is near the speed of light, relativistic effects begins to play the major role. The only thing I can imagine (I know that space and time will be deformed, but...) at this point is the increasing of the wheels and belt mass (relativistic mass); at the limit, this can lead to an absurd increase of gravitational force, and all will end up in a black hole.

I hope could explain some of the consequences of this imaginary situation, based in the known Laws of Physics.

[Valkyrie]

Yes,
Because I deem it so!
And also, because the force of the engines works separately than the landing gear.
The engines are pushing up against the wind whilst the conveyor belt only works upon the landing gear.
so if the plane was at any throttle, it would move regardless the runway's movement.