Bench > OHP

[bacon]

We get it man. You're a big fan of teh Mythbusters. You're a god among men and I bow before you.

Now, if you'll indulge me...do you happen to know the min cable tension allowed on the pitch axis of a C-90 King Air?

 

[JPC]

WTF? Does he still believe a toy plane will take off on a treadmill? With no air speed?

 

[bacon]

WTF? Does he still believe a toy plane will take off on a treadmill? With no air speed?

That's the gay part of the question. The real question is, will the airplane move forward. The apparent answer is "yes". I know jack shit about physics so I can't tell you why. But anyone who know's anything about airplanes can tell you it'll take off if it moves fast enough.

 

[ChaseT.]

We get it man. You're a big fan of teh Mythbusters. You're a god among men and I bow before you.

Now, if you'll indulge me...do you happen to know the min cable tension allowed on the pitch axis of a C-90 King Air?

42 Newtons

 

[bacon]

42 Newtons

*shrugs*

If you say so. Now we both know.

 

[JPC]

That's the gay part of the question. The real question is, will the airplane move forward. The apparent answer is "yes". I know jack shit about physics so I can't tell you why. But anyone who know's anything about airplanes can tell you it'll take off if it moves fast enough.

It will not take off unless it moves through the air. It will move forward on the treadmill easily. No matter how fast the treadmill is going, the plane will go the same speed on the treadmill as on the ground with the same propellar speed. But no treadmill is long enough for the plane to get enough air speed to take off.

 

[ChaseT.]

It will not take off unless it moves through the air, which it won't on a treadmill. Unless somehow the treadmill creates enough air pressure underneath the plane from the rapidly moving belt. But that is not the point of the question. Its air speed vs ground speed and it matters not how fast the wheels are rolling.

 

[JPC]

Dammit Chase, now you have to do one for my edited post. Learn patience.

 

[bacon]

It will not take off unless it moves through the air, which it won't on a treadmill. Unless somehow the treadmill creates enough air pressure underneath the plane from the rapidly moving belt. But that is not the point of the question. Its air speed vs ground speed and it matters not how fast the wheels are rolling.

That's what I thought too and I work for a company that builds airplanes....

But the infallable Mythbusters and our own ChaseT say otherwise. Damned if I know why...not that I care, at this point.

 

[ChaseT.]

It will not take off unless it moves through the air. It will move forward on the treadmill easily. No matter how fast the treadmill is going, the plane will go the same speed on the treadmill as on the ground with the same propellar speed. But no treadmill is long enough for the plane to get enough air speed to take off.

 

[JPC]

I would have to see the Mythbusters to believe it.

 

[Lorenz]

When you all refer to OHP, I assume you meen sitting on a bench?... and SOHP meens standing?

 

[ChaseT.]

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[JPC]

It took off because it had air speed. The question I thought everyone was talking about was would it take off if it was motionless on the treadmill. Like I said in my earlier post, the plane will move through the air as easily on a treadmill as on the ground. What the wheels are doing matters not.

This vid says it all better
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[hunto]

That's the gay part of the question. The real question is, will the airplane move forward. The apparent answer is "yes". I know jack shit about physics so I can't tell you why. But anyone who know's anything about airplanes can tell you it'll take off if it moves fast enough.

But if the belt negates the speed, no airflow can develop under the wings, hence no lift.

 

[hunto]

I would have to see the Mythbusters to believe it.

Mythbusters is not infallible. I refer you to the ep about the car differential being pulled out via a chain. They got the testing methodology wrong- wrong type of car. It made all the difference.

The plane does not take off. No ground speed = no lift. The belt can exert enough force on the airplane to keep it still, thus it stays on the ground.

 

[JPC]

But if the belt negates the speed, no airflow can develop under the wings, hence no lift.

The belt cannot negate the speed. Plains are not driven by their wheels like cars, but by the propellar. The propellar will pull it through the AIR no matter what the wheels and ground are doing.

 

[Donut62]

Someone for the love of God lock this thread.

 

[hunto]

The belt cannot negate the speed. Plains are not driven by their wheels. But by the propellar. The propellar will pull it through the AIR no matter what the wheels and ground are doing.

The belt can exert enough force to hold the plane still. If the thrust of the engines pushes the plane forward 1 mph, the belt accelerates the other way, negating the forward movement. This can continue until the engines are at full throttle, and the belt is whirring the other way. The original question postulated a belt under the wheels, that can move in response to the wheels moving. So if the belt 'detects' the plane starting to inch forward, it accelerates the other way, negating that forward movement.
I know about thrust vs wheel drive. But the plane must move forward relative to the air around it for the plane to achieve lift.

 

[ChaseT.]

The belt can exert enough force to hold the plane still. If the thrust of the engines pushes the plane forward 1 mph, the belt accelerates the other way, negating the forward movement. This can continue until the engines are at full throttle, and the belt is whirring the other way. The original question postulated a belt under the wheels, that can move in response to the wheels moving. So if the belt 'detects' the plane starting to inch forward, it accelerates the other way, negating that forward movement.
I know about thrust vs wheel drive. But the plane must move forward relative to the air around it for the plane to achieve lift.

No.