re: Myth Busters/Can a plane take off on a conveyor belt

I didn't bother reading through the full 12 pages of this thread, so I apologize if I bring up points already made.

In a perfect system (as others have pointed out is nearly impossible to have) the plane would never create enough forward speed to generate the windspeed over the wings to create the lift needed for takeoff.

A real world example of this is Navy carrier operations. The ship turns into the wind and increases the speed of the ship in order to increase the wind-speed over the flightdeck because even with the thurst of full afterburner and the steam catapult, the planes can't gather enough speed in the short distance to takeoff without that added help.

I think realistically that at some point the ability of the treadmill/conveybelt to keep up with the force of the plane's thrust would allow the plane to move down the pathway - much like a person can walk up a down escalator.

I wonder if the type of plane would make a difference. Given a treadmill/conveyor belt that was large enough (hypothetical) would the thrust produced by the airplane have an impact? A small prop plane like a Cessna or Piper can only generate so much thrust. A 747 or other such superliner can spool up those big jets to create many times more thrust than the prop plane.

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I didn't bother reading through the full 12 pages of this thread, so I apologize if I bring up points already made.

In a perfect system (as others have pointed out is nearly impossible to have) the plane would never create enough forward speed to generate the windspeed over the wings to create the lift needed for takeoff.

A real world example of this is Navy carrier operations. The ship turns into the wind and increases the speed of the ship in order to increase the wind-speed over the flightdeck because even with the thurst of full afterburner and the steam catapult, the planes can't gather enough speed in the short distance to takeoff without that added help.

I think realistically that at some point the ability of the treadmill/conveybelt to keep up with the force of the plane's thrust would allow the plane to move down the pathway - much like a person can walk up a down escalator.

I wonder if the type of plane would make a difference. Given a treadmill/conveyor belt that was large enough (hypothetical) would the thrust produced by the airplane have an impact? A small prop plane like a Cessna or Piper can only generate so much thrust. A 747 or other such superliner can spool up those big jets to create many times more thrust than the prop plane.

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I've said it before, and I'll say it again: there's an inexhaustible supply of stupid.

And, apparently, some of it is in my town.

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Is it the amount of engine thrust in miles per hour?

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because of equal and opposite reactions, the force of thrust is essentially the same as the forward force of the plane.

I think velocity is being measured as the ground relative speed of the fuselage. If it's going 5mph, the conveyor would rotate backwards so as to create a 5mph backward linear velocity on the top of the conveyor.

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because of equal and opposite reactions, the force of thrust is essentially the same as the forward force of the plane.

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so basically what's happening is that the plane is thrusting forward, and the belt is pushing backwards against the wheels, causing the wheels to spin twice as fast as they normal would (on solid ground)

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Hey Boo, just wondering though, how is speed determined though?

Is it the amount of engine thrust in miles per hour?

Is it kind of like a car, where the engine is synced to know how hard its engine is working?

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I would assume so. The treadmill should be synced to the engine thrust, whatever mph that would be. I'm no expert on how jet engines work, but they obiously know how fast they're flying, so they must know how much thrust the engines produce and can relate that to a groundspeed.

So... the treadmill would be going the same speed as the plane's thrust/groundspeed, in the opposite direction.

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Thanks. I'll take that insult a lot better than the one last night who claimed I was someone named Ryan with a new screen name.

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Did it seem like I was insulting you?

Sorry. No insult intended.

Now go read through the thread to find out why your post was so stupid.

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so basically what's happening is that the plane is thrusting forward, and the belt is pushing backwards against the wheels, causing the wheels to spin twice as fast as they normal would (on solid ground)

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So... the treadmill would be going the same speed as the plane's thrust/groundspeed, in the opposite direction.

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additionally, the plane would move forward on the conveyor belt, at the same speed as it would on the ground right?

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additionally, the plane would move forward on the conveyor belt, at the same speed as it would on the ground right?

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yep.

ETA: aside from friction in the wheels. that kinda acts like a little bitty brake. But not much of one. So it'll take a tad more thrust from the jets in order to get the plane to the same forward velocity.

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ETA: aside from friction in the wheels. that kinda acts like a little bitty brake. But not much of one. So it'll take a tad more thrust from the jets in order to get the plane to the same forward velocity.

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so you if you lined up a runway the same lenght of the conveyor belt, the plane on the runway would get to the end first?

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so you if you lined up a runway the same lenght of the conveyor belt, the plane on the runway would get to the end first?

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presuming the same thrust from the jets, yes.

I.e., presuming equal thrusts, it would take a slightly longer conveyor for the plane to achieve takeoff velocity.