Quick Physics Test..

ok I grabbed this off another forum, but it invoked several different ideas.. Lets try it with you guys...

A plane is standing on a runway that can move (some sort of band conveyer).

The plane moves in one direction, while the conveyer 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).

Can the plane take off and why?

Don't run off and Google, but I'll let you know that Mythbusters tried this.. But lets see what you think first...

no it doesent, it stays in the same place, like a running treadmil

Oh and repost

no it doesent, it stays in the same place, like a running treadmil

 

 

 

Oh and repost

No air is passing over and under the wings to give lift (high/low pressures) etc, plus the engines would overheat too I'd thought.

EDIT: So no it won't take off. Just ask supradibbs

this has got to be an issue with air flow and density so i guess the plane will not move

Stays in the same place as there is no wind speed going over/under the wings.

Oh and repost

Well bugger me, I couldn't find it.. Oh well...

It just stays where it is, the movement below it will just spin the wheels, similar to a rolling road....or have I read the original post inccorectly?

and then it will prob burst into flames

It's not a car ffs. The engines work on the air around it which ISN'T moving, the treadmill thing just means the unpowered wheels will spin twice as fast as normal as the plane takes off perfectly normally.

It's not a car ffs. The engines work on the air around it which ISN'T moving, the treadmill thing just means the unpowered wheels will spin twice as fast as normal as the plane takes off perfectly normally.

If the plane cannot move forwardly (like down a runway) of speeds upto 150mph then how is the wind (lift) going to be created under the wings at 150mph speed.

It's not a car ffs. The engines work on the air around it which ISN'T moving, the treadmill thing just means the unpowered wheels will spin twice as fast as normal as the plane takes off perfectly normally.

You must be the 2nd yes then Ian.

It cant take off as no air is rushing over the wings thats what makes normal (as opposed to a jump let can vector its thrust)planes airborne

It's not a car ffs. The engines work on the air around it which ISN'T moving, the treadmill thing just means the unpowered wheels will spin twice as fast as normal as the plane takes off perfectly normally.

is this a jet or propellor plane? i thought the principle of a plane taking off is to create more pressure under the wing than on top(the same reason that a glider needs to be propelled) i could be wrong though;)

plane stands still, so doesn't create enough uplift under wings as no air moving over them:)

If the plane cannot move forwardly (like down a runway) of speeds upto 150mph then how is the wind (lift) going to be created under the wings at 150mph speed.

ITS NOT A CAR

THE ENGINES/PROPELLER ACT ON THE AIR

How does a plane normally accelerate down a runway for crying out loud, a moped engine on each wheel?

I despair.

he he he, just like the other forum... Who's going to get bored first and check Mythbusters?

I clicked no but then realised that the power doesnt get fed to the wheels of a plan, it pushes on the air no the conveyor belt. But then again, i should have clicked blown up, because the wheels will end up moving faster and faster and faster then probably fall off, then the plane would hit the deck, the conveyor belt would sent it flying of the end of itself in the opposite direction and then smash boom

ITS NOT A CAR

 

 

THE ENGINES/PROPELLER ACT ON THE AIR

 

How does a plane normally accelerate down a runway for crying out loud, a moped engine on each wheel?

 

I despair.

ITS NOT A CAR

 

 

THE ENGINES/PROPELLER ACT ON THE AIR

 

How does a plane normally accelerate down a runway for crying out loud, a moped engine on each wheel?

 

I despair.

the thrust from the engines push it down the run way....... not the wheels i know this.

But the movement of the plane down the run way (by thrust) would be cancelled out as the runway is moving backwards, therefore no forward motion will be created thus giving zero lift.

the thrust from the engines push it down the run way....... not the wheels i know this.

 

But the movement of the plane down the run way (by thrust) would be cancelled out as the runway is moving backwards, therefore no forward motion will be created thus giving zero lift.

The wheels are free to move as they want though surely, so they would just spin faster and faster......then fall off (as the plane move forward)

ITS NOT A CAR

 

 

THE ENGINES/PROPELLER ACT ON THE AIR

 

How does a plane normally accelerate down a runway for crying out loud, a moped engine on each wheel?

 

I despair.

if it is a jet it will thrust the air out behind the wings not under them the propeller will not create enough air pressure under the wing to ensure take off, it has nothing to do with the wheels being powered, it is to do with the volume of air under each wing, or am i reading this all wrong:)

easiest way is to imagine

You are running on a treadmill but the treadmill is too fast, you run quicker. (whereas a jet would thrust more) but you stay central to the treadmill, and if you held your arms out theres no air traveling under your arms the same speed you are running, rofl.

As the question stipulates, the conveyor moves the exact same as the plane but backwards, back to the treadmill speed thought.

if it is a jet it will thrust the air out behind the wings not under them the propeller will not create enough air pressure under the wing to ensure take off, it has nothing to do with the wheels being powered, it is to do with the volume of air under each wing, or am i reading this all wrong:)

All wrong

Imagine a toy car on a treadmill with your finger at the back off it. Run the treadmill at any speed you like and push forward on the car. Does the car stay where it is?

I don't think the plane will be going anywhere. I believe that given a hypothetical situation the wheels will spin up to their maximum velocity and then overheat and explode or catch fire. The thrust being created by the engine would be cancelled out (through the friction between the wheels and the runway/conveyor) by the backwards movement of the conveyor, hence no lift will be created as there will be the same volume or air under the wings.

easiest way is to imagine

 

You are running on a treadmill but the treadmill is too fast, you run quicker. but you stay central to the treadmill, and if you held your arms out theres no air traveling under your arms the same speed you are running, rofl.

 

As the question stipulates, the conveyor moves the exact same as the plane but backwards, back to the treadmill speed thought.

Perfect example, the power to move you forwards on the tread mill is going through your legs (I.e wheels) but the power from the plane is not being fed through the wheels (I.e Legs) its coming from your arse therefore you will fly forward off the tread mill