Seen a few references to this recently and I can't remember what the definitive answer was, searched the forum with no luck.

So….will it or won't it?

You need to ask?

no it won't. End of thread.

It will, apart from on Tuesdays.

YES, for crying out loud, YES!

Pook, why not?

Ian, the sex of the plane is not an issue.

It's been done, with a model aircraft. Yes, it does take off. You've gotta be a bit retarded to think otherwise too, being as a plane isn't driven by it's wheels….. 🙂

Actually, the initial stipulations are hazy. Are the engines on but the conveyor belt is going in the opposite direction….someone fill me in.

no

Only if it has wings

Yes, the definitive answer is yes. Anyone who says no is WRONG!!

End of thread.

being as a plane isn't driven by it's wheels

That's the important factor!

Of course it would, it would need the conveyor belt to be the same length as the runway, it does not, as some seem to think, make it suddenly possible for planes to take off on the spot!

It depends on how you conceptualise the conveyor belt.

I can't find the original thread, but its a funny read!

Plane & Conveyor Belt – Mythbusters, video included

Ah wings hit the treadmill…

wind speed over the wings = 0 as it is stationary (im assuming its stationary otherwise whats the point of the q?)

0 wing speed = 0 lift.

if it isnt stationary then yes. but then its not really on a converyor belt is it? its 1000m meters away having hurled off into the distance…

The point is, with the engines running it doesn't make any difference… sod it. I can't be bothered.

Yeah… and then you turn the engines on and it moves forward!

The conveyor belt can continue to move backwards at the same rate the plane moves forward, all that happens is the speed the wheels are travelling at is double the groundspeed of the plane.

Am I missing an ironic in-joke?

Although groundspeed will be simulated by moving the wheels, this won't create any lift, as air won't be travelling over the wings.

Therefore it won't take off. Isn't it obvious?

Perhaps with a tiny model plane the surface of the conveyor belt will cause sufficient friction with the surrounding air to move a small body of air in close proximity, but this would be pretty limited.

Plane in a wind-tunnel would be a different matter.

Cheers, Rich

Mythbusters: http://mythbustersresults.com/episode97

Put a model car on a treadmill and push if forward with your finger. Does it move forwards? Of course it does.

Mythbusters say YES!

Nurse, my pills…

What if the conveyor belt is moving backwards (relative to the plane) at the plane's take-off speed?

Rich, yes you are missing something.

The planes wheels aren't driven!!!

The engines move the AIR

It's a classic misdirection in the question.

What it should really say is "If you put a plane on a very powerful, very long, very wide treadmill and fired up the engines, then would the treadmill operator be able to prevent the plane taking off by running the treadmill in the opposite direction?"

To which the answer is most definitely, NO, they can't. The plane will be able to take off as normal.

This was about a real plane on a hypothetical 10000ft conveyor, not model planes and treadmills!

And of course it will, I don't get why people can't understand that!

Although groundspeed will be simulated by moving the wheels, this won't create any lift, as air won't be travelling over the wings.

Why would you simulate movement with the wheels!? The thrust will push the plane forward, the wheels will be moving quicker than the plane.

The point you're all missing is that the little tug truck wouldn't be able to pull the plane onto the conveyor belt in the first place as its wheels would turn at the same speed as the belt and it wouldn't go anywhere.

The crucial point is whether you conceptualise a treadmill (moving under the plane and just spinning its wheels) or an actual conveyer belt which physically moves the whole plane.

More to the point if the plane falls off the conveyor belt, who should zaskar sue? 🙂

Ahhh, but if you put your luggage on a conveyor belt some of it will turn up in Alacante three weeks later, the rest well end up on the carousel, empty, with your pants snagged on everyone elses luggage

IanMunro – Member

More to the point if the plane falls off the conveyor belt, who should zaskar sue?

LOL!

More to the point if the plane falls off the conveyor belt, who should zaskar sue?

😆

IanMunro – Member

More to the point if the plane falls off the conveyor belt, who should zaskar sue?

LOL!

+1

The crucial point is whether you conceptualise a treadmill (moving under the plane and just spinning its wheels) or an actual conveyer belt which physically moves the whole plane.

Does it?
– Plane sits on the conveyor
– conveyor starts moving
– plane moves backwards
– plane power up engines
– plane stops moving, although wheels continue to rotate
– thrust exceeds treadmill speed, so plane moves forwards
– plane takes off

It's just incredible to me that people don;t get this 🙂

+1 for GrahamS rewording of the question to remove any ambiguity.

Now.. imagine you replace the wheels of the plane with little hovercrafts so the plane isn't rolling on wheels at all but is in fact floating an inch of the tarmac…

🙂

Will a plane take off in a windtunnel?

ie if the engines aren't on but you fire wind at it really fast, will it start to fly?

Now.. imagine you replace the wheels of the plane with little hovercrafts so the plane isn't rolling on wheels at all but is in fact floating an inch of the tarmac..

What a bit like a Harrier?

Surely it's not time for this thread to happen AGAIN?!

ie if the engines aren't on but you fire wind at it really fast, will it start to fly?

Yes

Of course not because the wheels won't be going round 🙄

Although if it was 4×4 it might, with locked differentials'n'all.

The Southern Yeti – Member

Will a plane take off in a windtunnel?

ie if the engines aren't on but you fire wind at it really fast, will it start to fly?

if you could stop it moving backwards without restricting up and down movement…yes

( although i think planes rely on the thrust to help with lift though – maybe wrong here)