Imagine a plane is sitting on a massive conveyor belt, as wide and as long as a runway. The conveyer belt is designed to exactly match the speed of the wheels, moving in the opposite direction. Can the plane take off?

lol this is kinda a no brainer. Iam gussing that it cant.......iam i wrong? XD

I'm assuming yes. You're not losing momentum, so I would guess that it would eventually take off.

Um, no?

If the plane is increasing speed, but the conveyor belt is matching it and going in the opposite direction, it would just sit there like a car caught in mud with the driver stepping all the way down on the pedal.


It's like the way a treadmill works.
You run on it but set it to a speed that matches yours so you don't go flying off the end, or running straight into the controls in front of you.

But I thought you're trying to make the plane go up? Does it really need to travel a certain (physical) distance before it actually goes up diagonally? I can understand that you're going nowhere if you're running on a treadmill, but what if your goal is to go diagonally up? Think helicopters. They don't need to travel a certain distance before it flies. It only needs enough momentum to get the d*mn thing to go up.

Well, if it's a VTOL craft then it may be able to do so.

But a normal plane needs air flow over the wings to provide lift.
If it's not moving, it's not going to get any of that. Unless a particularly strong breeze happens to come by.

Nice. See I would not know. I don't know anything about planes.

A car's wheels make it go. A plane's wheels do not; they are free-spinning. The plane's engines makes it go, and the engines do not have any connection with the ground. If you assume that the wheels are what makes a plane move, then no, the plane would not move. However, since its its the engines that make the plane move, the plane would eventually start moving forward and take off.

this sounds like the Avro Vulcan and the Typhoon Eurofighter, the Vulcan technically should not be able to fly because of its size and the Eurofighter because of the way it's been designed... or something

:huh What?
The specific type of plane isn't relevant to the question other than if it is VSTOL plane, which we can assume its not.

Avro Vulcan

Avro Vulcan XH558 returns to flight

^
that plane should not be able to fly because of its size

The plane won't move. The plane may still be moving fast enough to take off, but the net velocity of the system from both the plane and the belt would end up at zero, providing zero air resistance, which is what the plane would need to take off.

Will it take off?


...I will answer your question with one of my own.

Can a man defy teh gravities?

No. the plane wouldn't get the air pressure under its wings which it requires to get 'lift' and actually fly.

putting a plane on a coveyor would require the 'Air to go though the plane' instead of the 'plane going though the air' (if that makes sense o_O)

and a jet plane would probably melt the conveyor anyway.

The Stealth Bomber should also not fly because its shape is aerodinamically unstable but they can because they have super-computers onboard that perform 1000's of minute corrections to the plane during flight, leaving major direction changes to the pilots.

If these SC's fail then the plane becomes unstable and will most likely jsut plummet imto the ground and shatter in a billion dollar-ish explosion

Obviously not. In order for a plane to 'take off,' there must be air moving across the wings. When there is enough speed and velocity, due to the way the wings are designed, the air lifts the plane off of the ground. If a plane's wheels are just moving, is that not the same as a car in mud, as someone else said? The plane will not fly.

The conveyor belt doesn't match the speed of the plane, it matches the speed of the wheels.

And that's what I was implying?

but if the plane's engine is moving the plane, and the wheels are moving becuase the plane is being pushed forward, then the wheels are going to be rolling to match the speed of the plane's forward momentum, there fore pushing the conveyer belt to match the wheels which are matching the forward momentum caused by the engine, there fore the conveyer belt will be matching the engine and there fore the plane will not actually go anywhere.

Basically the plane needs to move to get air under it's wings to get lift.

At best, the only thing you probably could use a convoyor for is to shorten the length of the runaway, get the engines up to speed and turn the conveyor off and set the aircraft set off down the runaway and it should technically get into the air sooner than it would have if it had set off from a standing start.

It'd very, very loosly resemble the cataputs that aircraft carriers use to quickly get jets up to speed to take off, but with a commercial jet, you'd need a HUGE BLOODY CATAPULT!!!

So the plane (I'll assume it's a airliner) is sitting on a sort of treadmill. The pilot fires up the engine, the plane starts to move a little, causing the wheels to push the treadmill floor backward (which takes the plane backwards with it). The wheel and the treadmill are even in speed and opposite in direction, so the plane does not take off.

And if you have any basic knowledge of aerodynamics, you know that aircraft use their wings to generate lift so that they can fly. To generate this lift, they require wind to move under them at high speeds (the shape of the wing causes the wind to move downward, pushing the plane up).

Now, as the plane is merely spinning its wheels on the treadmill and not moving, it won't fly. It did move forwards slightly at first, but it requires far more speed in order to fly.

You guys keep assuming that the plane doesn't move. The plane will move.

Hmm. . .

*thinks it through again*

The plane will move. But I don't think it'd be moving fast enough to fly.

it won't move, if you run 5mph on a 5mph conveyor, you'd stay in the same spot. this would also happen to something doing 700mph on a 700mph conveyor.
(hell make the conveyor faster and see the plane go backwards!)

again, the plane needs to move to get air under it's wings to generate the lift required to fly.

basically it's this...

Conveyor speed---><----Plane speed = standstill
500mph - 500mph = 0mph

(this doesn't count for stuff like wind and friction, etc though, so it might move a tiny little bit)

No, it certainly won't get off the ground. As the others said, you need airflow. However, the engines might set up an artificial wind, and that might get it off.