Can the Plane Take Off ?

[Ross]

Contradicting yourself there, you said that the conveyour tracks the planes speed so that it remains stationary.

Actually, he didn't say it remains stationary at all... reading it again, he says the conveyor belt tracks the plane's speed. So, is this wheel speed we're assuming??

The only way the plane would stay stationary would be if the conveyor belt accellerated quick enough to convert all the forward momentum given to the plane from thrust into inertia in the wheels and heat through friction, which would amount to alot of wheel speed, very quickly. Am I right in saying this?

Think of it as a diagram:

thrust--> Plane <--friction/wheel inertia

If these values aren't equal, the plane accelerates. Now that's even more basic than the physics of lift.

[newsh]

Or like this, you run your S2 up to 150mph on the new 4x4 rolling road at MRC, if you put your head out of the window will your new hair do get messed up?

[S2 Ant]

There would be more to it than that tho, its airspeed would still be 300mph, but the rate of decereration would depend on its drag coeffiecient lol.... finally can make some use of a-levels maths and physics lol

[S2 Ant]

Or like this, you run your S2 up to 150mph on the new 4x4 rolling road at MRC, if you put your head out of the window will your new hair do get messed up?

Why strap it down then?

The accereration wants to make the car move forward because the wheel speed wants to be greater than the rollers...... works on same principal as my above post about the treadmill

[Alistair C]

Thrust generated by the engines will move the plane forward.
A moving conveyor will not have any effect on the planes actual movement. The wheels will just be turning twice as fast as they would normally.

Why do peoplew think a moving conveyor will be able to counteract the engines thrust??

Now if it was also in a wind tunnel, with the airflow matching the engine's thrust, then that would be a different matter!

[Corey]

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).

plane speed/ conveyer speed.

quoted verbatim

plane stays still.

If we are adding other criteria to the original statement then the outcome changes

[Mark Halligan]

Thrust generated by the engines will move the plane forward.
A moving conveyor will not have any effect on the planes actual movement. The wheels will just be turning twice as fast as they would normally.

Why do peoplew think a moving conveyor will be able to counteract the engines thrust??

Now if it was also in a wind tunnel, with the airflow matching the engine's thrust, then that would be a different matter!

I think Alastair is right, the planes propulsion system is 'pushing' against air so the plane will move forward, regardless of what is happening to the ground under its wheels. As he says the wheels will just move twice as fast.

If the subject was a wheel driven vehicle the effect would be different as as its wheels would be pushing against the conveyor belt and it would stay still.

[4WheelDrifter]

I agree with Alistair. Unless the wheel bearings are shot and the friction of the wheels overcomes the thrust.

[Corey]

Oh god this could go on allllllll night, planes stays still/plane moves (shrugs shoulders and thinks it a bit like blondes/brunnets)
I know one thing though I was probably on that plane last time I flew as it took ages to get anywhere!!!

[4WheelDrifter]

Every action has an equal and opposite reaction.

[Audi_CQ]

A car/vehicle that uses wheels to put the power down would stay still on the conveyor belt, but a plane will not be affected off the conveyor belt that's turning the other way(other then as stated earlier: landig wheels will turn at 2 x airspeed)
Should be obvious really if you just stop thinking on cars

[B16 UGG]

The plane will simply roll of the conveyor or if the plane is tethered ,as in the rolling road previously mentioned , the plane will not move and the wheels will not rotate as it is the thrust that moves the plane and not the driven wheels as the car is ,so the convevor is irelevant because the wheels are not driven

[Audi Parts Guru]

right this is becoming quite the hot topic on a few other forums,

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

Discuss.......



Well can it ?

In a nutshell, no

[volcano rs]

if it was possible why would RAF have such long runways at a cost of millions of pounds when they can launch them from their back garden on a conveyor belt .

[Audi Parts Guru]

But, if the plane is gonna just sit still on the conveyor belt, where's all the energy from the 1,000's of LBS of thrust going? Remeber the plane doesn't accelerate due to power transmitted to the ground

I'm voting for the "yes, if the wheels don't drop off first" option.

All of that thrust is being used just to keep the plane stationary, otherwise it would go the same way as the conveyor belt which in this case would be backwards