[Science Question] Will a plane take off?

I've said all along the wheel speed doesn't matter. The plane will still not be moving relative to the air around it, so will not take off.

I bet your house on it too.

We'll go 50/50 if he doesn't know. Don't think asking the 'audience' would prove too fruitful.

the whole aregument is that the wheels are gong the same speed as the conveyor. the planes movement is provided by engines. take this as an example.

the planes engines ar at full pelt if it was on a runway its wheels would be going say 200 mph or whatever. so in response to the question the conveyor would be doing 200 mph. there for the plance would not move. as the question said if the conveoyr was matching the speed of the wheels at any given time. so no mater how fast the wheels are going the conveyor is matching it.

im im walking at 5mph on a treadmill then the mill itself is going round at 5mph and im not going forwards or backwards im staying in the middle. same with the plane

he asked the wrong question

are we all trying to answer colins first question or has another been asked?

I wasted a day on this you'd be wise to ignore

thats what ave been saying

and what I've been saying:

lol 115 post and we're all saying the same thing

Are you all on this salvia?

The distance the wheel moves forward is
d = A - B
where A = the velocity of the outer rim of the wheel and B = the velocity of the top of the conveyor
Relative to a point marked on the ground next to the 'starting point' of the plane, the ONLY way the plane will move forward is if the plane's wheel covers more ground then what it's sitting on. Normally this is the runway which doesn't move so d = A - 0 = A
If the plane is sitting on a conveyor (B) that moves at one quarter the speed of A then B = .25A
d = A - 0.25A = 0.75A
So the wheels would have to spin faster to cover the same d

But since A = B
d = A - A = 0

The plane couldn't move.

^
That's basically the result of the post in the other forums.

Thats childs play

a real quote:

"Rolls Royce RB.211 engine produces 140-270 kilonewtons of thrust.

900,000 pound aircraft = about 4000 kN.

For the wheels of the aircraft, let's assume teflon on steel (which would be a higher coefficient of friction then something that's lubricated properly, or that uses ball-bearings)

4000 kN x 0.04 = 160 kN friction.

Which means there is at least 400 kN left over to propel an airplane. (A 747 has four of these engines) 400,000N / 400,000kg = 1 m/s^2 Not much, but it's a start. And that's all it needs.

We're all familiar with acceleration, but how many of us have heard of "Jerk". Just like acceleration is a change of speed, Jerk is a change of acceration. most moving object usually experience negative jerk because of the increase of air friction at higher speeds, and this might suggest that the airplane might not be able to take off because it will reach a terminal velocity. A 747 with 1 MN can travel at about 950 km/h. So let's say the drag is 1MN @ 950 km/h. Usually if we cut the speed in half, then the drag would be divided by four. But for the sake of over-exaggerating the number to try and stop this plane from flying, i'll cut the numbers proportionally. so 1MN = 950km/h then 400 kN = 380 km/h

A MiG has an unusually fast take-off speed of 340 km/h. Still below this artificially low terminal velocity.

But,
As soon as the airplane starts moving in generates lift. This lift reduces the Normal force acting on the plane, and thus reduces the force of friction acting on the plane, which increase acceleration. Therefore increasing lift, reducing friction, increasing velocity, increasing lift, reducing friction etc."

The plane flew.

Thanks joe, you just confirmed everything i was thinking.

Re: Re: [Science Question] Will a plane take off?

we he must of thought there was a big fan infront of the plane as well ??

*edit as i never relised this one was 7 pages long
*

Was it a harrier jump jet?

Re: Re: Re: Re: [Science Question] Will a plane take off?

obviously the engines were on, because if they werent on and the plane was on a runway it wouldnt take off anyway.