Plane on a treadmill

[Pox]

If there is no (or very little friction) on the wheels, why would they simply not spin in one place? What method converts the energy from the plane wheels into movement for the plane?

The wheels have got nothing to do with moving an aircraft down a runway, they are jsut there to keep the plane from scraping on the ground. No force is applied thru the wheels to move the plane, it's all supplied by the engines generating thrust.

 

[bwana]

Being that the plane not being propelled by the wheels it would move forward, lift would still be generated, and the plane would fly. The inconsequential treadmill could spin as freely as it likes.

http://www.straightdope.com/columns...the-opposite-direction-can-the-plane-take-off

 

[Brown Fox]

:wtf: :wtf: NO

 

[oober]

If there is no (or very little friction) on the wheels, why would they simply not spin in one place? What method converts the energy from the plane wheels into movement for the plane?

Ok what do you mean by spin in the same place? Why would they spin at all of there is no force generated from the engines? The whole plain would simply fall off the treadmill if there is no force from the engines. If the engines do provide a force that force then first needs to cancel the treadmill's backwards motion. If you then want the plain to generate enough lift you need additional force to start the plane moving forward and create lift. It's not that hard.

 

[Mars]

eish.... :erm:

Fail much at school?

not as much as you obviously....

 

[oober]

What? how the hell would the treadmill negate the lift? Its created by the wings and the engines on the wings....

Serious? These okes must be joking. It's a ploy to make us all go crazy in disbelief.

 

[Rosaudio]

not as much as you obviously....

Haha..

That's a bold comment judging by you earlier post :erm:

 

[hammell]

Watch the Mythbusters movie. They make a huge treadmill, get a real plane, and it takes off. I don't know how much more conclusive you want this to be...

 

[oober]

Watch the Mythbusters movie. They make a huge treadmill, get a real plane, and it takes off. I don't know how much more conclusive you want this to be...

We never said it was impossible. Just that it would require extra force from the plain to take off.

 

[bwana]

We never said it was impossible. Just that it would require extra force from the plain to take off.

You're being sidetracked by the treadmill. The wheels aren't driving the plane forward - the prop is. The plane still moves forward at the normal speed.

 

[Mars]

Haha..

That's a bold comment judging by you earlier post :erm:

:Bangs head against wall:
Flight basics : The plane is pulled through the air by the engine, either propeller or jet. While being pulled, this creates airflow over the wings. The shape of the wings then create lift.
Whether the plane has wheels, pontoons or ski's is irrelevant to the above process. Weather its on a treadmill or on a tarmac has nothing to do with this process.

The only thing that can affect this process is wind speed. Tell me do you feel the wind in your hair when you run on the treadmill? No? That's because the treadmill generates no wind.
Its like saying a sea plane would have to fly in the same direction as the current to take off. It doesn't, it can take off in any direction, wind allowing.

 

[Keeper]

This has been discussed before. The thing to remember here is how the plane gets lift. It gets it from the propeller (or jet) of the plane, which creates forward movement

Sorry, but you are Wrong.

I'll see If I can get a pic - but I promise you it is not the engine.

It will also show that wheels have nothing to do with it.

 

[SlinkyMike]

Of course it will take off, because the thrust is generated by the engines on the wings and not the wheels. In fact it would only be on the treadmill for a few seconds before the thrust from the wings pulled it off. The only difference it would make is that the planes wheels would spin twice as fast for the few seconds it was on the treadmill.

Saying that it would not take off is like saying you would not be able to use a rope to pull someone off a treadmill because the treadmill is running faster than you are pulling.

What? how the hell would the treadmill negate the lift? Its created by the wings and the engines on the wings....

Lift is created by the movement of air over the wings... that is not what you said. I'd be inclined to believe that you simply worded your response poorly if not for the rope/buddy on a treadmill analogy, you shot yourself in the foot there becuase if not for that you could have rode in on bwanas coat tails after he linked the straight dope article...

Being that the plane not being propelled by the wheels it would move forward, lift would still be generated, and the plane would fly. The inconsequential treadmill could spin as freely as it likes.

http://www.straightdope.com/columns...the-opposite-direction-can-the-plane-take-off

...see that Madman88? ..."would move forward" ..."lift would be generated" ...quite different from your statement that the 'engine on the wings create lift', no?

 

[oober]

:Bangs head against wall:
Flight basics : The plane is pulled through the air by the engine, either propeller or jet. While being pulled, this creates airflow over the wings. The shape of the wings then create lift.
Whether the plane has wheels, pontoons or ski's is irrelevant to the above process. Weather its on a treadmill or on a tarmac has nothing to do with this process.

The only thing that can affect this process is wind speed. Tell me do you feel the wind in your hair when you run on the treadmill? No? That's because the treadmill generates no wind.
Its like saying a sea plane would have to fly in the same direction as the current to take off. It doesn't, it can take off in any direction, wind allowing.

So where does all the airflow come from when then plain is not moving forward?

Edit: The article does sort out the confusion.
If the plain is standing still and the treadmill starts and the plain is moving backwards and force is then applied the engines first have to cancel out the backwards motion after that it can take off. If the plain is held in the air and suddenly dropped on the treadmill it won't have to cancel the backwards motion and can take of normally. So it depends on how you understand this problem...

 

[Keeper]

Lift is NOT Generated by WHEELS MOVING, not is it by an ENGINE.

Lift comes from the shape of a wing, particularly by the air that moves past it.

Thank you all for coming.

 

[Mars]

Lift is created by the movement of air over the wings... that is not what you said. I'd be inclined to believe that you simply worded your response poorly if not for the rope/buddy on a treadmill analogy, you shot yourself in the foot there becuase if not for that you could have rode in on bwanas coat tails after he linked the straight dope article...



...see that Madman88? ..."would move forward" ..."lift would be generated" ...quite different from your statement that the 'engine on the wings create lift', no?

 

[Mars]

So where does all the airflow come from when then plain is not moving forward?

nowhere... but the wheels don't move the plane. At all. The engines do. On the wings.

 

[hammell]

Sorry, but you are Wrong.

I'll see If I can get a pic - but I promise you it is not the engine.

It will also show that wheels have nothing to do with it.

You don't need a picture - lift equation: L = (1/2) d v2 s CL . v is the important one here - it is the measurement of RELATIVE airflow over the wing. You're quite right though in saying it's not the engine only, as potential energy can create lift i.e. dropping a plane from another plane/building. It is in this case the forward movement of the plane generated solely by the propellor that will provide the lift required for the plane to take off. I hate to name (job) drop, but I used to be a commercial pilot and studied aerodynamics and can assure you that for the purpose of this argument, the plane will fly.

 

[hammell]

And the final nail in the coffin of this discussion:

 

[oober]

I think like bwana's article said is that the question leaves too much detail out and then allows you to make assumptions etc. Hence the confusion.

But I agree that if the plane's wheels are perfect and there was almost no friction in the bearings the plain would be able to take off almost normally. Just hope the wheels don't pop...