Will the plane take off??

[AngusG]

A plane is standing on a runway that can move (some sort of band conveyer). The plane moves in one direction, while the conveyer belt 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).

Will the plane take off or not?

[screamager123]

Originally Posted by AngusG

A plane is standing on a runway that can move (some sort of band conveyer). The plane moves in one direction, while the conveyer belt 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).

Will the plane take off or not?

The plane will take off... The forward motion provided by the engines are uneffected by the reverse countering motion on the wheels caused by the conveyor belt..

[Bartmanekul]

No.

Because if I have this right, the plane is stationary (even though its using its engines and the conveyor is moving). Thus by not moving, its not getting any lift from the wings.


Edit: Ohh, good one Screamager123. Looks like I fell into the trap.

[Micky]

Wings need air flow under them in order to take off.

[purp]

The question asks... "Will the plane take off?". No, not while it's sitting on the conveyor. However, it will eventually leave the conveyor and crash into something or.. indeed, take off.

The wheels on the plane are not powered during take off and are only there to support the plane while providing as little friction/drag resistance to the ground as possible.

The thrust generated from the plane is far, far superior to the drag caused to the wheels of the plane, therefore the plane would accelerate to the end of the conveyor.. and what happens after than depends on the environment... crash, take off whatever.

The principle is kind of like having a small cylinder, like a small roll of tape or something. Place it on a table and kinda put pressure on the side closest to you so you spin/roll it away. The tube will accelerate away from you, but in a backspin, because the forward motion you provided is more than the drag from the table, and eventually causing it to return to you.. or at least in your direction.

[AngusG]

I think it depends on how you interprate the question as well...

Mythbusters proved that yes the plane will take off, but the first time I read it I though it was impossible to prove... If there is no friction whatsoever between the wheels and the conveyear belt, and the conveyer belt can well and truly spin at the same speed as wheels than no, the plane will not take off...

In reality though, yes it will...

[Bartmanekul]

Depends if it was a harrier, or other VTOL plane as well :D

[purp]

That's extremely true ;-)

Though I wouldn't like to be there when the rubber from the conveyor catches light form the vertical engines..!

[gavinguinness]

I LIKE IT!

Assuming that the conveyor can match the maximum trust speed of the plane, the answer is that the plane will end up going backwards on the ground.

Because, the plane requires air under the wings for lift, achieved by forward momentum. If the conveyor pulls it back effectively keeping it stationery, it will not achieve lift and will eventually run out of fuel and roll back.

I think.

EDIT: Actually it will, because the force is against..... erm.. I don't know!

[Bartmanekul]

Thinking about it, perhaps I was right. If the conveyer could truely move the same speed as the plane, it wouldnt gain any ground. But finding such a conveyor, as wellas being able to keep the plane on it, would be extremely difficult.