Airplane on a treadmill

[Stilev]

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LetÃÆââââ¬Å¡Ã¬Ã¢ââ¬Å¾Ã¢s say that we have a jet airplane (like a 747 for example) trying to take off on a giant runway sized treadmill. The treadmill, which turns in the opposite direction that the plane is facing, is capable of precisely matching the speed of the airplane. HereÃÆââââ¬Å¡Ã¬Ã¢ââ¬Å¾Ã¢s a visual to bring it all together (not drawn to scale obviously)

 

 

 

This is a pretty common question asked, and I usually just ignore it. It seemed so obvious that the answer is no, it wouldn't take off. Now it seems so obvious the answer is it is possible, it depends entirely on how much friction is in the wheels. A stationary plane on a treadmill moving 50mph will move with the treadmill at 50 mph. The plane turns on its engines, and it will appear as if it is stationary, and the treadmill is just spinning the wheels. Throttle up, and it will be moving against the treadmill. The treadmill at this point makes little difference how fast it is going, depending on the friction of the planes wheels. The plane will move forward.

 

 

 

when you turn on the jet engines the treadmill will increace its speeds to compecent for this

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When the treadmill increases its speed that will merely cause the wheels on the plane to spin faster while the plane continues to move forward.

 

 

 

that would only work if there is something holding up the plane, keeping it from going back, the friction could work to make if go forward in one sense, but there will be more pulling back the of the turning of the wheel, dont get me wrong, i see where you going with this :wink: and i can see why you think it would work, but it just wouldn't work

[No_OnE]

If the plane were on a treadmill that were matching it's speed then the velocity of the plane would be zero. If the velocity of the plane is zero then there is no airflow for the plane to be able to lift off. Correct me if I'm wrong.

[indy500fan]

If the plane were on a treadmill that were matching it's speed then the velocity of the plane would be zero. If the velocity of the plane is zero then there is no airflow for the plane to be able to lift off. Correct me if I'm wrong.

 

 

 

If the velocity of the plane is zero, the plane will not lift off.

[scn64]

[hide]

LetÃÆââââ¬Å¡Ã¬Ã¢ââ¬Å¾Ã¢s say that we have a jet airplane (like a 747 for example) trying to take off on a giant runway sized treadmill. The treadmill, which turns in the opposite direction that the plane is facing, is capable of precisely matching the speed of the airplane. HereÃÆââââ¬Å¡Ã¬Ã¢ââ¬Å¾Ã¢s a visual to bring it all together (not drawn to scale obviously)

 

 

 

This is a pretty common question asked, and I usually just ignore it. It seemed so obvious that the answer is no, it wouldn't take off. Now it seems so obvious the answer is it is possible, it depends entirely on how much friction is in the wheels. A stationary plane on a treadmill moving 50mph will move with the treadmill at 50 mph. The plane turns on its engines, and it will appear as if it is stationary, and the treadmill is just spinning the wheels. Throttle up, and it will be moving against the treadmill. The treadmill at this point makes little difference how fast it is going, depending on the friction of the planes wheels. The plane will move forward.

 

 

 

when you turn on the jet engines the treadmill will increace its speeds to compecent for this

[/hide]

 

 

 

When the treadmill increases its speed that will merely cause the wheels on the plane to spin faster while the plane continues to move forward.

 

 

 

that would only work if there is something holding up the plane, keeping it from going back, the friction could work to make if go forward in one sense, but there will be more pulling back the of the turning of the wheel, dont get me wrong, i see where you going with this :wink: and i can see why you think it would work, but it just wouldn't work

 

 

 

As I see it, the jets would be "holding it up". They would be applying a forward force on the plane. As the treadmill runs in the opposite direction, it would be pushing on the bottom half of the wheels. If the treadmill is spinning to the West this would cause the bottom half of the wheels to move towards the West which is the direction they need to move for the plane to move East. But even if the wheels were spinning in the opposite direction, the plane still doesn't rely on it's wheels to push it forward so it wouldn't make much of a difference anyway.

[knives669]

Well, I don't think it will. But, should the plane take off (which I don't think it will of course. :P) I'll stand corrected.

 

 

 

I definitely agree that this is a job for Mythbusters. :D

[Celt23]

Well, I don't think it will. But, should the plane take off (which I don't think it will of course. :P) I'll stand corrected.

 

 

 

I definitely agree that this is a job for Mythbusters. :D

 

 

 

Lol this reminds me, a few days ago a chan prankster posted a topic like this in the mythbusters forum (don't ask me how I know :uhh: ) and the people on there made lots of pages of debate over it and even started to seriously consider trying a large-scale expirement.

 

 

 

Anyways this will not work. I know quite a bit of aerodynamics and you need air moving over the wings at a respectable speed to create lift so the plane can actually take off. If the plane on the treadmill is a VTOL craft then that is another story entirely.

[rocketman089]

Nevermind, now that I think about it I guess it does work..

[scn64]

Nevermind, now that I think about it I guess it does work..

 

 

 

Yeah, that's exactly how it was with me. At first I thought there was no possible way it could take off. Now I think the exact opposite.

[Lovelydude]

Well, um, the question is flawed. The treadmill might theoretically be able to match the plane's speed with its belt, but the problem is that you don't travel whilst on a treadmill, so no speed is involved, save the wheels of the plane spinning. How about referring to counter-acting the force the plane creates with its engines?

 

 

 

If a normal plane (no VTOLs) were to be placed on a treadmill that matched the force created by its engines, the plane would not travel so it would not takeoff. Duh.

 

 

 

I hate this question. D:

[nicrune007]

No wind Speed = No lift..

 

so it wont take off...

 

 

 

Try buying a plane and a really really really big threadmill

 

 

 

and just try

[Guest]

Simply, no.

 

A plane wing has a curve at the top of it. As it passes through air, the air moves faster and a lower pressure area is formed above it.

 

Eventually, the high pressure below the plane pushes the wing(and the plane) up into the low pressure area, and that is when the plane leaves the ground.

 

 

 

If there is a treadmill that matches the opposite speed of the plane, there is no low pressure being formed above the plane. In fact, the low pressure point is below the wings, right above the treadmill.

 

 

 

The plane will never lift off.

 

 

 

Yeah misplacedme summed it up for me before I could reply with the same answer. No has to be the answer.

[Somnambulism]

It's funny to see people resorting to insults just because they can't see the other side of the coin; it is the ultimate forum irony.

 

 

 

For the first 2 minutes of this topic I thought like everyone else, then when scn64 posted his explanation I understood it.

[rocketman089]

It's funny to see people resorting to insults just because they can't see the other side of the coin; it is the ultimate forum irony.

 

 

 

For the first 2 minutes of this topic I thought like everyone else, then when scn64 posted his explanation I understood it.

 

Indeed.

[Mercifull]

Its quite funny to see how many people here have no idea about how planes work :D

[rocketman089]

"The only purpose the wheels serve here is to hold the plane up, and to eliminate most of the friction between the plane and the ground. When the engines fire up, the plane will still start moving forward. The only difference will be that the wheels are turning twice as fast as normal."

 

 

 

The plane will take-off as the speed of the conveyorbelt is irrelevant. The treadmill and wheels cancel eachother out, yes. But the jets provide a net +force.

[warri0r45]

Simply, no.

 

A plane wing has a curve at the top of it. As it passes through air, the air moves faster and a lower pressure area is formed above it.

 

Eventually, the high pressure below the plane pushes the wing(and the plane) up into the low pressure area, and that is when the plane leaves the ground.

 

 

 

If there is a treadmill that matches the opposite speed of the plane, there is no low pressure being formed above the plane. In fact, the low pressure point is below the wings, right above the treadmill.

 

 

 

The plane will never lift off.

 

 

 

Have you been inside my head? o_0 In other words, those were more or less my thoughts. The plane would probably need air movement under the wings and the scenario you posed (topic starter) seems to leave the air around the system rather stagnant relative to the aircraft.

 

 

 

Anyway is there supposed to be an answer and if so what is it? (apologies for not reading through the entire thread).

[rocketman089]

Anyway is there supposed to be an answer and if so what is it? (apologies for not reading through the entire thread).

 

 

 

The answer is: it's a loaded question. If you use the logic that I used above your post, then you'd have to assume the wheel and conveyor can go infinite speeds. I'm not sure, I just know it's a loaded question and can be interpeted in a few ways.

 

 

 

In my head, it takes off.

[scn64]

Simply, no.

 

A plane wing has a curve at the top of it. As it passes through air, the air moves faster and a lower pressure area is formed above it.

 

Eventually, the high pressure below the plane pushes the wing(and the plane) up into the low pressure area, and that is when the plane leaves the ground.

 

 

 

If there is a treadmill that matches the opposite speed of the plane, there is no low pressure being formed above the plane. In fact, the low pressure point is below the wings, right above the treadmill.

 

 

 

The plane will never lift off.

 

 

 

Have you been inside my head? o_0 In other words, those were more or less my thoughts. The plane would probably need air movement under the wings and the scenario you posed (topic starter) seems to leave the air around the system rather stagnant relative to the aircraft.

 

 

 

Anyway is there supposed to be an answer and if so what is it? (apologies for not reading through the entire thread).

 

 

 

I've never seen an official answer from a well respected group of "experts" or anything. As far as I know, it's just been passed around the internet, mainly on forums like this. As rocketman indicated, I think the question is intentionally written to be confusing (I didn't write it myself). I have my own idea of what would happen but no way of proving it.

[britrockdude]

Wow, that is quite a brianteaser. Let me ask my Dad who's a pilot, he'll know.

 

 

 

My guess is that regardless of whether it's literally going anywhere, the propulsion caused by the engines would be enought to push it forward, and eventually lift it off of the treadmill.

 

 

 

Just my guess though! :roll:

[remoteman]

Haha thats is one seriously awesome question, i'm going to ask my physics teacher tomorrow. I was totally with it not moving, but it will take off, i looked it up on google, because the wheels do not affect the plane's acceleration at all. Very cool.

[warri0r45]

Haha thats is one seriously awesome question, i'm going to ask my physics teacher tomorrow. I was totally with it not moving, but it will take off, i looked it up on google, because the wheels do not affect the plane's acceleration at all. Very cool.

 

 

 

Show us your link! :) I'm not doubting you but I'd be interested to hear the reasoning in laymans if possible (physics is not my forte).

[Sir_Alex85]

This is just a question this rised up for me, and I'm curious about it... And didn't want to make a new topic.

 

 

 

Let's say you're on a plane..or a train. Or an (automobiles!) bus. If you were to jump, would it move underneath you?

[warri0r45]

This is just a question this rised up for me, and I'm curious about it... And didn't want to make a new topic.

 

 

 

Let's say you're on a plane..or a train. Or an (automobiles!) bus. If you were to jump, would it move underneath you?

 

 

 

Depends if you land behind where you started. :P

[Lateralus]

This is just a question this rised up for me, and I'm curious about it... And didn't want to make a new topic.

 

 

 

Let's say you're on a plane..or a train. Or an (automobiles!) bus. If you were to jump, would it move underneath you?

 

 

 

No, you are moving at the same speed as whatever you're travelling in.

[assassin_696]

This is just a question this rised up for me, and I'm curious about it... And didn't want to make a new topic.

 

 

 

Let's say you're on a plane..or a train. Or an (automobiles!) bus. If you were to jump, would it move underneath you?

 

 

 

Welcome to relativity :)

 

 

 

(no)

 

 

 

Oh, and the plane takes off by the way.