Imagine a plane is sitting on a treadmill...
 

Imagine a plane is sitting on a massive hypothetical conveyor belt, as wide and as long as a runway. The conveyor belt is designed to match the speed of the plane exactly but moves in the opposite direction. The engines are running at take-off thrust, the brakes are off, etc. Everything is normal save for the fact the plane is on a treadmill.

Can the plane take off?

Discuss :)

Tom...

Re: Imagine a plane is sitting on a treadmill...
 

Not much to discuss. No, where would the lift come from as the plane would not be moving through the air?

Re: Imagine a plane is sitting on a treadmill...
 

Will it take off vertically, and as soon as the wheels leave the conveyor, it will move forward??

My head still hurts from reading the "secret" thread, and this isn't helping :p

Re: Imagine a plane is sitting on a treadmill...
 

Excellent, it's working :)

End of the working day now, gotta go, but i'll check on your progress later ;)

Re: Imagine a plane is sitting on a treadmill...
 

Bugger, that sounds right.

Re: Imagine a plane is sitting on a treadmill...
 

I hate you.


:frown::p:rofl:

Re: Imagine a plane is sitting on a treadmill...
 

Yes because the movement of the aircraft is generated by the thrust from the engines.

The treadmill makes no difference whatsoever other than to make the landing gear wheels spin even faster than they normally would as the aircraft does its take-off roll.

Re: Imagine a plane is sitting on a treadmill...
 

I think you're right, Steve. If the treadmill is moving as fast as the aircraft but in the opposite direction, the wheels will simply rotate twice as fast as normal and the aircraft will take off.

If the treadmill is programmed to move the same speed as the wheels then AX's scenario arises and the aircraft doesn't move forward no matter how much thrust the engines generate, so the wings generate no lift and it can't take off.

Re: Imagine a plane is sitting on a treadmill...
 

What a clever man :thumbsup:

Re: Imagine a plane is sitting on a treadmill...
 

So, essentially the plane is still. No, it can't take-off.

Re: Imagine a plane is sitting on a treadmill...
 

Is there a ZOOM discount code for this flight?

Re: Imagine a plane is sitting on a treadmill...
 

But the thrust from the engines acts on the surrounding air and would push the aircraft forward no matter what the treadmill does, for the aircraft to remain still wouldn't the wheels have to be driving wheels like a car?

The question is how do you get the aircraft on the treadmill in the first place and to get it to stay at the end of the runway (treadmill) before applying the thrust?;):)

Re: Imagine a plane is sitting on a treadmill...
 

The thrust from the engines may be acting on the surrounding air but unless the airplane is not actually in contact with the treadmill e.g. actually flying, then, using the Oakvillian assumption about the treadmill it would still not go anywhere. The thrust aft is counterbalanced by the speed of the treadmill so, <he pontificates, dredging up half remembered A level physics?>... surely the two thrusts or energies cancel each other out.

If your scenario is valid then why hasn't someone developed this system for short take off for small planes then?;)

I'm sure IainK will be along in a moment to set us all right. Him being an engineering type.

Re: Imagine a plane is sitting on a treadmill...
 

what's the wind speed and direction !!!!

as takeoff is entirely dependant on 'air speed' not 'ground speed' !!!!

Re: Imagine a plane is sitting on a treadmill...
 

No it won't take off.

If the thrust from the engines force the plane forward at 200mph, the treadmill will run backwards at 200mph. The wheels of the plane are doing 400mph, but the plane isn't moving. No movement = no lift.

I think!