An airplane on a treadmill: will it take off?

[chef]

A) If the plane remains stationary relative to the ground, it will not take off.
B) If the plane moves relative to the ground, it will take off.
C) The person operating the conveyor belt cannot by himself make the plane remain stationary relative to the ground.

[Churchill]

A) If the plane remains stationary relative to the ground, it will not take off.
B) If the plane moves relative to the ground, it will take off.
C) The person operating the conveyor belt cannot by himself make the plane remain stationary relative to the ground.

Air surrounding the wings.

Hth.

[chef]

Air surrounding the wings.

Hth.

thanks

[gingerjedi]

Are we assuming that the aircraft is using it's engines on the treadmill?

The aircrat takes off due to the lift caused by the airflow over the wings being slower than under the wings because the route taken by the air over the curved top of the wings is longer than the route under the flat bottom, and therefore the air pressure is lower above the wings. If the treadmill is standing still then the aircraft is also standing still and doesn't have enough air flowing over and under the wings to generate lift.

Perhaps at some unfeasible speed the treadmill itself would cause sufficient airflow to the wings, but I rather suspect that the aircraft's wheel bearings would have melted by then.

The wheels are free running so the fact that the treadmill moves is almost irrelevant, the engines may need to counteract the treadmill but it would be a small amount to compensate.

It's all about the airplane moving through the air that surrounds it, like I said the treadmill is nearly inconsequential.

[BoredBloke]

The thrust generated by the engine(s) is not transferred to the wheels (as mentioned by others) therefore the treadmill is irrelevant.

The aircraft will take off unless anchored down.

I don't agree - it's related to the lift generated on the wings which gets it off the ground and without a strong forward motion through the air it will not generate the lift. Also, how are the engines used to left it without the wings. They don't point towards the ground do they - surely without the air pressure generated by the forward motion you could do nothing but propel it forwards. This would be negated by the treadmill.

Obviously the treadmill must be able to run at speeds sufficient to keep it at zero mph

[BlackenedBiker]

I don't agree - it's related to the lift generated on the wings which gets it off the ground and without a strong forward motion through the air it will not generate the lift. Also, how are the engines used to left it without the wings. They don't point towards the ground do they - surely without the air pressure generated by the forward motion you could do nothing but propel it forwards. This would be negated by the treadmill.

Obviously the treadmill must be able to run at speeds sufficient to keep it at zero mph

Correct - next question

[Menelaus]

This was done on Mythbusters, I believe ...

http://www.youtube.com/watch?v=01Q83yxdDaI

[The Lone Gunman]

I don't agree - it's related to the lift generated on the wings which gets it off the ground and without a strong forward motion through the air it will not generate the lift. Also, how are the engines used to left it without the wings. They don't point towards the ground do they - surely without the air pressure generated by the forward motion you could do nothing but propel it forwards. This would be negated by the treadmill.

Obviously the treadmill must be able to run at speeds sufficient to keep it at zero mph

No, the thrust is not transferred to the wheels therefore the treadmill is irrelevant.
Think of the treadmill as ice. A car will spin its wheels like mad, but a plane will just zip along therefore generating airspeed and so lift.

Unless the treadmill is so big that it acts as a chock, but I will bet my Eurofighter against you JJB jogger anyday.

[BrollyBonce]

One of those annoying questions where there is insufficient data to answer the question.

If the treadmill is free-wheeling, the aeroplane will take off.

If the treadmill is switched off, it acts as solid ground and the aeroplane will take off.

If the treadmill is being used specifically to hold the aeroplane back, it will not achieve sufficient lift to take off, but there will be so much turbulence by the jets being on full, I would doubt a large aircraft would remain stable.

It's a broken question; there is no way to provide a sensible Yes/No answer without making assumptions.

[Churchill]

I don't agree - it's related to the lift generated on the wings which gets it off the ground and without a strong forward motion through the air it will not generate the lift. Also, how are the engines used to left it without the wings. They don't point towards the ground do they - surely without the air pressure generated by the forward motion you could do nothing but propel it forwards. This would be negated by the treadmill.

Obviously the treadmill must be able to run at speeds sufficient to keep it at zero mph

You're wrong.

One of those annoying questions where there is insufficient data to answer the question.

If the treadmill is free-wheeling, the aeroplane will take off.

If the treadmill is switched off, it acts as solid ground and the aeroplane will take off.

If the treadmill is being used specifically to hold the aeroplane back, it will not achieve sufficient lift to take off, but there will be so much turbulence by the jets being on full, I would doubt a large aircraft would remain stable.

It's a broken question; there is no way to provide a sensible Yes/No answer without making assumptions.

So are you.

Hth.