[Andy B]

Basically they say that once the wheels overcome basic friction the thrust generated by the engines acts like normal and the plane moves forward as it normally would. Thus generating lift. It's still wrong though. And they DO have weird facial hair.

[Yudster]

Ah, so the plane isn't actually stationary? Makes more sense.

Is there an "Aeronautics For Dummies?"

[TIAL]

Surely if the plane is moving, the wheels have to be going faster than the conveyor belt - which wouldn't happen as we have to assume the belt always perfectly matches the speed of the wheels.

[Yudster]

No - the opposite forces of the conveyor belt and the whells eventually result in zero friction so the plane is moved purely by the thrust from the engines. I think.

Where is Console when you need him?

[Chris]

Planes are moved by air, not by wheels. If you hold the wing of a plane on a conveyor, the wheels spin. The thrust of the engine against the air has absolutely nothing to do with the speed of the wheels.

At the point of take off the only difference is that the wheels would be turning twice as fast, which has no bearing on the energy needed for the engines to propel the plane, nor the speed of airflow required over the wing for the plane to take off.

[Boboff]

Do you feel the air against your face when you run on a running machine ? No. Your legs are moving but you are not.

A plain would not take of in the scenario outlined above.

Think Swan on a river, stationery, but it's ickle legs are kicking like a bugger under the water to maintain that position, it it spread it's wings when the river was flowing at the speed of flight, whilst still kicking like a bastard, he would not go up in the Sky.

[Console]

Your point relies on the faulty premise that it's the wheels on the ground that provide the thrust for a plane, as Chris (and possibly someone else above) said, it's the turbines/propeller that provide the kinetic energy for a plane.

This argument has been done to death so many times, and it only really takes a basic understanding of the mechanics of a plane to figure out.

[Boboff]

No, I know that the wheels are not propelled, as with a swan, it is the wings which create forward motion and lift.

I really was in the ATC you know, and have flown a glider all by myself.

I agree with your post, but not with it being aimed at me, we were agreeing that the whole thing is rubbish, wern't we ? Although apparently most of the things I type here are not understood by some of the best ex car hire bankers in Scotland. Still I have grouting to get on with.

[Console]

If that's the case then I must of misinterpreted your post. I still stick with my second point though, the number of times I've read, heard or been apart of this argument is ridiculous, I've never been able to figure out why it's such a widespread question.

[S4B]

I'd never heard the question before. Mind you I still don't understand the answer. I trust Console as supreme geek though so ..............

Console is right!

[Boboff]

I have never heard it, but it is blumin daft question. LOCK THE THREAD !

[TIAL]

Sorry Boboff.

[Yudster]

... I've never been able to figure out why it's such a widespread question.

Ok, this is, as simply as I can explain it, the reason I (and probably others) am still confused.

Lift is generated by airflow over the wing of the plane.

If the plane is stationary, whatever other forces are acting on it, surely there can't be any airflow over the wing of the plane?

If there is no airflow over the wing of the plane to create lift, how can the plane take off?

If there IS, in this scenario, lift being generated, then bearing in mind that lift is generated by airflow over the wing, HOW is the lift generated? Surely either the plane or the air needs to be moving at a considerable speed to create lift?

None of the explanations offered so far have actually answered that, as far as I can tell - at least, not in a way that I can access with my limited knowledge of physics.

[Console]

If the plane is stationary

And if the plane is not stationary?

[Yudster]

I thought, given the scenario as described, that the whole point was that it WAS? If this is, indeed, the place where my confusion arises, well, thats good, because I can understand that!

Honestly though Console, I'm not trying to be argumentative - i don't care whether its true or false, I just want to know which and why!

[TIAL]

I think the answer is that the plane basically moves forward anyway, with its wheels moving at twice the speed.
However, I fail to see how it can move forward if the belt is moving at exactly the same speed - regardless of where the thrust comes from.

[S4B]

Tial, I blame you for this!

[TIAL]

There's no real way of me avoiding that blame since I posted it!

[Yudster]

I just want to UNDERSTAND................not necessarily in total depth and detail, but just enough so I know what to think.

[Console]

Honestly though Console, I'm not trying to be argumentative

I know, but that is where the confusion appears to arise from. A common use of the wheel is to provide motion, through one form or another, but a plane uses wheels for no such purpose.

However, I fail to see how it can move forward if the belt is moving at exactly the same speed - regardless of where the thrust comes from.

The wheels are only there to reduce the 'friction' (not technically the correct word, but I can't think of the right one at the moment) between the plane and the ground - unless the brakes are applied, which would make the wheels no longer spin and increase the 'friction' between the plane and the ground (assuming that the wheels are in contact with the ground), the wheels have no further role in the motion of the plane; you can good as ignore them and pretend they're not there, they just basically act as rollers from then on.

[DannyBoy]

[foot-loose]

It's a bit off topic, but since we've answered the original question, I thought I'd throw this spanner in the works:

"A plane is standing on a runway that can move (some sort of band conveyer). The plane moves in one direction, while the conveyer moves in the opposite direction. This conveyer has a control system that tracks the plane speed and tunes the speed of the conveyer to be exactly the same (but in the opposite direction). Can the plane take off?"

I used to like you. Now I don't. I knew this would bloody happen. Bloody stupid bloody question.

Yes.

The damn thing takes off. If you want to argue more about it, PLEASE google the argument and find one of the threads that run to thousands of pages on another forum. Let's try and not have one on here as well!

Next?

[S4B]

I said that!

[TIAL]

Oh, I'm really sorry if I touched a nerve there. I didn't mean to piss anyone off - I just figured that since the thread had had its original question answered I'd post something vaguely related (as there have been a fair few discussions about riddles/questions etc). I do apologise. I guess I'll leave this thread now.

On the other hand, S4B when did you say the same thing? I thought you'd not seen it before.

[foot-loose]

Oh you can ask any other riddles you wish. Any at all. Start a whole new thread if you want.

Just don't mention aeroplanes and conveyor belts. I'm STILL arguing this with a 'mate' from about a year and a half ago.