Thread: Airplane on a treadmill

Originally Posted by BigJon

Sure, but without the engine running it would be a pretty short flight.

No!
It won't get off the ground at all.
As soon as it begins to get a little bit of lift, the wheels will begin to slip on the conveyor belt so the plane will stop picking up speed.
It will never get enough speed to lift off.

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Originally Posted by vnx205

No!
It won't get off the ground at all.
As soon as it begins to get a little bit of lift, the wheels will begin to slip on the conveyor belt so the plane will stop picking up speed.
It will never get enough speed to lift off.

Precisely. The coefficient of friction multiplied by (the plane's weight due to gravity minus the lift generated) would be less than the aerodynamic drag and therefore no actual liftoff would take place. To exceed lift off speed a mechanical connection like a tow rope or sling shot is required.

However if the conveyor stopped at the edge of a cliff some flight might take place.

Originally Posted by bee utey

Precisely. The coefficient of friction multiplied by (the plane's weight due to gravity minus the lift generated) would be less than the aerodynamic drag and therefore no actual liftoff would take place. To exceed lift off speed a mechanical connection like a tow rope or sling shot is required.

However if the conveyor stopped at the edge of a cliff some flight might take place.

Id have though That would depend on the plane and the pilot.

once enough airspeed was generated to get the tail up enough elevator could be used to pitch the nose down and "fly" the aircraft downwards (areo drag would go up hugely but we get to ignore that in this case its an improbably/impossibly massive conveyor powered by a perpetual motion/energy hiclone) to maintain downwards pressure on the wheels.

you probably couldnt do it in a jumbo but one of those canadian short strip jobbies could probably pull it off

If you set no flaps youd also lower the lift and areo drag of the plane so you might also be able to get it up above full flaps take off speed with 0 flaps set, set full flaps and pull back.

IF it could be done it'd be a very short flight unless you had some very fast spool engines.

Originally Posted by vnx205

No!
It won't get off the ground at all.
As soon as it begins to get a little bit of lift, the wheels will begin to slip on the conveyor belt so the plane will stop picking up speed.
It will never get enough speed to lift off.

Sent from my U8815 using AULRO mobile app

Your assuming the plane lifts off at minimum flying speed though. If you waited until you were significantly above flying speed and then pulled back it would fly, inertia being what it is.

I am with Blknight and BigBlackDog. I am pretty certain that you could get the conveyor belt fast enough while keeping the aircraft solidly on the deck to the "pop" it up in the air with some of the excess speed. Manipulating control surfaces as required, as you would never take off in any aircraft at stall speed.

Originally Posted by bee utey

I'd like to pose a slightly different question: Could you launch a plane (engines not running, wheel brakes firmly applied) by using a perfectly flat and extremely long conveyor belt?

Absolutely it will launch.

Originally Posted by ramblingboy42

Absolutely it will launch.

Wrong again, there's an explanation of why a few posts back. It will get to the point of creating lift, but never quite get off the ground as it will slip on the conveyor just as lift is achieved, then drop back again, and so on and so forth.

nope , in the first scenario it wont fly

in the second , it WILL launch.....no one has questioned how far...but it will.