Will a plane take off on a conveyor belt?

The movement of the airplane through the air and the wheels turning against the belt are two separate systems. The airplane would gain airspeed while the wheels turn twice as fast as for a normal take off.

 

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No. Why would it?

Attach it to a giant rubber band, that might work.

 

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yes, why wouldn't it?

 

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I read it thus: The conveyor moves backward at the same speed as the wheels spin (ie its tangential velocity).

 

I agree. But the airplane moves through the air if the engines are running.

 

Do you mean the airplane's engines are connected to its wheels? The airplane wheels are only to support the airplane's weight and to reduce the friction between the ground and the airplane as the airplane moves on the ground. The forward thrust is obtained by the propeller or jet engines which has nothing to do with wheels.

 

Why would you have the engines running? If you had engines then sod the bloody conveyor belt lol.

 

And your point is?

In this scenario, as I read it. You do not lift off the ground, because as someone said there is no air passing over the wings, because that conveyor belt is not allowing the plane to move. For most A/C to beat weight, you first need Lift via air passing over your airfoil.
Surely a physically near-impossible scenario(a belt that can go mach1+ ?) but apparently, barely worth discussing...

 

there is no connection between the conveyorbelt and the plane.
the wheelbearings effectively decouple the plane from the belt.

 

Do you imagine it's the wheels that make it fly?

 

lol Now I see what you are saying that the conveyor belt is "launching" the plane?

I don't think that is what he means.

 

Conveyer belt is not able to stop the plane, because it is the propeller or jet engine that puches the airplane forward. You would need to pull the airplane with incredible force to prevent it from moving forward. Conveyer belt is not fixed or attached to the plane and whatever way it moves it is unable to do what you want in the experiment.

 

Given interpretation #1, in which the conveyor is matching the wheels' radial (turning) speed and sliding along without friction under them:

Since we are postulating a frictionless conveyor belt, a pilot faced with a magical situation in which the movement of the ground under the wheels canceled out the lift from the airspeed could easily take off by simply braking the wheels. The conveyor would then stop, and the plane could take off on fixed, sliding wheels using the magically restored airspeed lift.

Given interpretation #2, in which the frictionless conveyor matches the forward speed relative to itself of the wheel center over it, we see that the conveyor must accelerate quickly to catch up with the difference between whatever speed it is going and the relative speed of the wheel (which is the conveyor speed plus the forward speed of the plane relative to the rest of the world). The conveyor can be said to have "caught up" when the ratio of the outer-context wheel forward speed to its speed plus the outer-context wheel forward speed gets near enough to unity that the difference falls below some quantum or Heisenberg derived limit of measurable value. This will be a very high speed, and the light show as the plane takes off would be worth seeing.

There is a third interpretation, in which the conveyor merely matches the worldspeed of the plane's wheel assembly (and struts, wings, body, or any other parts attached to the wheel assembly). But as this merely features a rapidly moving ordinary belt, with a plane taking off from it with its wheels turning like mad, it's boring.

 

If an African swallow is running on the conveyor belt, how many coconuts could it carry?

 

This conyever belt-launcher concept sounds a lot like the much-prophesied mass driver spacecraft launcher. Except that it doesn't need to accelerate its payload to escape velocity - not even Lunar escape velocity.

If it could throw a plane forward with sufficient speed relative to the surrounding atmosphere for the wings to generate lift greater than the aircraft's weight, then it would fly. It's that simple.

Never mind all this talk of frictionless belt/wheel interfaces: the aircraft's fuselage could be clamped to a fixed point on the conveyer surface, then the clamps release when the takeoff speed is attained. Clamps off, pull the joystick back - ailerons rise, plane starts to gain altitude! It's just like the common winch-launched glider, although the aircraft would be cut loose at the bottom of its climb, not the top.

 

As long as the conveyor belt moves fast enough to keep the planes engines from being able to accelerate the plane forward there will be no air movement(in a perfect system) resulting in no lift/flying. The wheel speed has no direct bearing on lift but big enough engines could cause enough air currents to lift plane theoretically. the main factor is weather or not wing moves forward.

 

What an utterly stupid thread.

 

Stupid, but I read it all. What does that say for me

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Yes, i'm trying very hard to pretend I did not participate. My reputation is on the line...

 

Come on. It does not matter how fast the conveyer belt move, the airplane will accelerate forward without any trouble. The engines are not connected to the WHEELS, it is not a car or 4 wheel drive, the airplane engines use AIR to get forward thrust.