Why the plane takes off in laymans (my) terms

Originally posted by Mat Kelley
There is no difference in how a plane propells itself whether it is flying or taxiing. I think we are all agreed that a plane has to travel fast enough through the air to create lift in order to fly. So just for a minute lets forget that.

Following this argument on, the only difference betweeen a plane flying 10cm off the ground and taxiing (assume thi ...[text shortened]... aft carriers would have worked this out rather than a hook and a bloody great big bit of wire!

This is tiresome.

The plane is NOT flying - end of dissimulation.

It would appear that the majority of those posting seem to agree with the tortuous argument that the original problem refers to a relationship of motion between the plane and an observer.

I'm afraid that I disagree totally.

Please note that the plane is stationary on the belt.

It starts to move - MUST mean relative to its stationary starting point.

Originally posted by sugiezd
This is tiresome.

The plane is NOT flying - end of dissimulation.

It would appear that the majority of those posting seem to agree with the tortuous argument that the original problem refers to a relationship of motion between the plane and an observer.

I'm afraid that I disagree totally.

Please note that the plane is stationary on the belt.

It starts to move - MUST mean relative to its stationary starting point.

This is indeed tiresome.

It doesn't matter what reference point you are using (stationary, moving runway, or plane).
If the engine is full throttle, or even half throttle at that, the plane will fly. It doesn't matter if the runway is complete ice, a lake, or moving backwards, the plane will accelerate to 55 knots through the air and fly. Rotate speed for a Cessna 172 is 55 knots indicated air speed, so it doesn't take much to get it off the ground.

The runway is of no consequence.

Originally posted by mlprior
This is indeed tiresome.

It doesn't matter what reference point you are using (stationary, moving runway, or plane).
If the engine is full throttle, or even half throttle at that, the plane will fly. It doesn't matter if the runway is complete ice, a lake, or moving backwards, the plane will accelerate to 55 knots through the air and fly. Rotate spee ...[text shortened]... speed, so it doesn't take much to get it off the ground.

The runway is of no consequence.

have you read the problem.

The plane is stationary.

It starts to move.

The belt moves at the same speed as the wheels are turning.

No matter how much power is applied by the engine, if the belt accelerates by the same amount, maintaining the same speed as the rotation of the wheels, the plane will not move.

I'm surprised how many postings about the problem has been written.
I don't see the problem at all.

If you don't have enough lift force at the wings, the plane can't lift.
Can it really be that hard...?

Rotating wheels has nothing to do with it.

Originally posted by sugiezd
have you read the problem.

The plane is stationary.

It starts to move.

The belt moves at the same speed as the wheels are turning.

No matter how much power is applied by the engine, if the belt accelerates by the same amount, maintaining the same speed as the rotation of the wheels, the plane will not move.

I have read the problem, too many times now.

The answer is still the same, the plane will fly when indicated airspeed is above the rotate speed. As soon as you pull back on the yoke at rotate speed, the plane will leave the ground.

The fact that the plane is on a moving runway, on water, on ice, or whatever is of no consequence. The propeller will move the plane forward through the air.

I fly every week, so I feel I have a good understanding on the mechanics of the plane.

Obviously you will not ever be convinced of the facts as many people in this thread have already tried.

Originally posted by sugiezd
Nice try but you go two steps to make the relationship - I take only one.

To also forget that acceleration is not mentioned.

What 2 steps?

Acceleration isn't mentioned. Oh no. The belt cannot change speed either then.
Wheels aren't mentioned. There goes your method determining the plane's speed.

It has come down to semantics. Further discussion is meaningless.

Originally posted by Marsan
It has come down to semantics. Further discussion is meaningless.

agreed!

Originally posted by mlprior
agreed!

Maybe it is a question of semantics.

Possibly, Australian English has drifted over the years.

Last try.

Plane and belt both stationary.

Pla'e wheels start to rotate.

Belt senses and moves at same speed.

No forward motion.

To advance, plane's wheels must rotate faster than belt.

Originally posted by sugiezd
Maybe it is a question of semantics.

Possibly, Australian English has drifted over the years.

Last try.

Plane and belt both stationary.

Pla'e wheels start to rotate.

Belt senses and moves at same speed.

No forward motion.

To advance, plane's wheels must rotate faster than belt.

The belt moves the same speed as the plane moves not the speed that the plane's wheels spin.

Originally posted by sugiezd
To advance, plane's wheels must rotate faster than belt.

Correct. And nothing in the problem forbids that.

Originally posted by sugiezd
Maybe it is a question of semantics.

Possibly, Australian English has drifted over the years.

Last try.

Plane and belt both stationary.

Pla'e wheels start to rotate.

Belt senses and moves at same speed.

No forward motion.

To advance, plane's wheels must rotate faster than belt.

What's with the fixation with the wheels? They aren't even mentioned in the question...

Originally posted by mlprior
I have read the problem, too many times now.

The answer is still the same, the plane will fly when indicated airspeed is above the rotate speed. As soon as you pull back on the yoke at rotate speed, the plane will leave the ground.

The fact that the plane is on a moving runway, on water, on ice, or whatever is of no consequence. The propeller will mo ...[text shortened]... ly you will not ever be convinced of the facts as many people in this thread have already tried.

Right Biggles.

No argument - the plane will fly when the airspeed is high enough. Small problem - it will never rise above zero.

Originally posted by XanthosNZ
The belt moves the same speed as the plane moves not the speed that the plane's wheels spin.

Define how you measure the planes speed - remember it must corrolate with the belt's speed.

Originally posted by Marsan
What's with the fixation with the wheels? They aren't even mentioned in the question...

True. Is it not a fair assumption that the plane has wheels?