will it take off?

[turnkey4099]

OK so the consensus is flight will occur. Now was someone right? And I know it wasn't me... at least not for the right reason....

But will it take off forward or backward if you are in Oz?

Harry K

 

[Tim_in_IA]

The plane wont take off. The first post says that the conveyor matches the speed of the plane. If that is true, then there is no lift since the plane is standing still in the wind....

If the plane could go faster than the conveyor then it would take off, but since it can't it doesn't. That is interesting to think about though.....

 

[weesa20]

Plane does not fly...no forward motion, no lift. Running on a treatmill or a bicycle trainer is a good example, no wind in my face but my speedo on the bike says 20 MPH with the tire turning against the trainer wheel. Similiar to a dyno-drum for autos- car doesn't move but tires turn.

The float plane on the river example is incorect because the forward speed of the plane is greater than the current of the river in the opposite direction, not the same as in this example. If it were the same speed, no forward motion and no lift.

W

 

[MrJimi]

Sense we were having so much fun debating the finner points of tire pressure in the other thread....

i thought this would be kinda fun...

a plane is standing on a movable runway( something like a conveyor).as the plane moves the conveyor moves but in the opposite direction.the conveyor has a system that tracks the speed of the plane and matches it exactly in the opposite direction.

the question is

will the plane take off or not?

(ps its been debated to death on other forums, its always fun to see how people present the theory behind there answer)

I read this first posting and !!
He never said the plane was running. He said the wheels were turning.
Think about it.
Jim

 

[Iowachild]

I read this first posting and !!
He never said the plane was running. He said the wheels were turning.
Think about it.
Jim

Jim, I have thought so much about it my head hurts! Let's discuss something easy like: "If you exceed the speed of light, will you travel backwards in time?"

 

[HTWT]

a plane is standing on a movable runway( something like a conveyor).as the plane moves the conveyor moves but in the opposite direction.the conveyor has a system that tracks the speed of the plane and matches it exactly in the opposite direction.

Everything is relative. If the plane is moving at 100fps relative to some position, then the track is moving at 100fps in the opposite direction relative to the same position.
1. If the position is a spot on earth then the plane is going 100fps relative to earth and in all reality will take off.
2. If the track is the reference position the plane will be going 200fps.
3. If the reference position is the plane the track will be going 200fps and the plane will not take off.
If we are observing and are taking the speed measurements and we are on earth and stationary?? then the plane is going 100fps and can take off. This is assuming that the plane is not laying on the track but is supported by wheels or some other support that doesn't add undue friction between the plane and track. The plane must have enough thrust to overcome a slight increase in friction in the rotation of the wheels.

 

[sandman2234]

What gear is the plane in? Is it gas or diesel? What rpm is it tacking? Does it have R-1 or R-3's? Is it 4x4 or just 2wd? These answers might give us something serious to think about...
David from jax

 

[Richard]

The plane wont take off. The first post says that the conveyor matches the speed of the plane. If that is true, then there is no lift since the plane is standing still in the wind....

If the plane could go faster than the conveyor then it would take off, but since it can't it doesn't. That is interesting to think about though.....

I would agree with that logic. I would add this twist (I've not seen it mentioned yet)

First, I must qualify that I interpret the question to mean the plan is stationary to a point in space, as such, no airflow.

For those of you who say the plane WOULD take off, I'd wonder this about LANDING said plane...

If the plane could be on a treadmill in my bedroom and take off, wouldn't it then follow that the plane could be airborn, coming in for a LANDING and land on the SAME tredmill without overshooting it?

My brain says NO way can it land like that because it's going to have forward AIRspeed, relative to the tredmills zero airspeed. As such, to land on the tredmill, it would have to stop in midair and plop straight down which isn't gonna happen.

My vote goes to it will NOT land like that, therefore, it can not take off like that!



My prize please...

 

[Richard]

What gear is the plane in? Is it gas or diesel? What rpm is it tacking? Does it have R-1 or R-3's? Is it 4x4 or just 2wd? These answers might give us something serious to think about...
David from jax

those questions only apply to a hydrostatic plane... well, except for which gear is it in!

 

[MossRoad]

O.K. I've changed my mind. It will fly... here's an example...

Put on some roller skates and stand on a treadmill.

Don't move your feet, just keep them together.

Have someone stand in front of the treadmill and throw you a rope. Hold the rope in your hands. Think of the rope as the air and your hands as the airplane propeller. The propeller pulls against the air just as your hands pull against the rope.

Start pulling yourself towards the person holding the rope.

Have a third person turn the treadmill on. Your wheels will spin at the same speed of the treadmill no matter what speed the treadmill is going.

Keep pulling the rope hand over hand, you will move forward no matter how fast the treadmill goes or until you lose your balance and fall.