Thread: Airplane on a treadmill

Just a simple question....

Are there any trained pilots in this forum who believe that this aeroplane will fly off the conveyor?

I think the only people who believe it will , are those who do not know the theory of flight and the difference between airspeed and groundspeed.

The only people who think the plane won't take off are those who are misled by the things mentioned on the question.
The question makes them think the treadmill will affect the plane. It won't. It has no effect.
Pilots are just as likely to be sucked in as anyone else.
The real issue is not whether you understand how planes fly.
The issue is whether you allow yourself to concentrate on the wrong thing and assume the treadmill will actually have an effect.
It won't.
The plane will take off.

Something to ponder. Drag on the wheels will slow the plane from getting to take-off airspeed, such as taking off on grass, long grass in particular, takes a lot longer for a given set of conditions. The conveyer will impart drag on the wheels I would guess, but I could be wrong.
A mate of mine, also a pilot, was asked by a guy once what was driving the wheels for take-off. Apparently the guys girlfriend ****ed herself laughing at him

The original question is poorly worded I think,which is confusing people. I think I get what it is trying to say but it's not a real clear picture

Originally Posted by ramblingboy42

Just a simple question....

Are there any trained pilots in this forum who believe that this aeroplane will fly off the conveyor?

I think the only people who believe it will , are those who do not know the theory of flight and the difference between airspeed and groundspeed.

Yes, me. It will fly off the conveyor belt (if the belt is long enough).

No matter what speed the conveyor belt does, it cannot stop the aircraft moving through the air. The wheels are not driven on the aircraft, so are irrelevant in this question. The wheels will just rotate faster than the airspeed.

Have a look at the question again:

An airplane is sitting at rest on a very powerful treadmill. You are at the controls of the treadmill, while I am at the controls of the airplane. On some signal, I begin to attempt to take flight in the plane, and you attempt to match my speed to try to keep me stationary. Will the plane take off?

The pilot attempts to take flight, so to do this they increase the airspeed of the aircraft. Aircraft don't use the wheels to drive it on the ground. So it will use a propellor or jet to create thrust.

The person with the conveyor belt attempts to match the speed to try and keep it stationary. As stated before, and by many on here, what the wheels do are independent of the airspeed. Try as the person with the conveyor belt may, they can't stop the aircraft with the conveyor belt only.

So to use some basic figures, if the aircraft gets airborne at 60 knots, then it will need 60 knots of airspeed. If the person with the conveyor belt makes the belt go at 60 knots to try and keep it stationary, all that will happen is that the wheels will rotate at 120 knots (groundspeed relative to the aircraft), and the aircraft will maintain 60 knots of airspeed.

So, to repeat, IT WILL FLY.

I'm happy to be proven wrong, although I'm not.

The original question is not poorly worded.
It is deliberately written to suck people in and obviously works. There are a lot of people who get fooled into thinking the treadmill will have an effect. It won't .

Originally Posted by ramblingboy42

Just a simple question....
.

A more important simple question.

When you eventually see the light, will you acknowledge that like so many others you have been tricked by a cleverly worded question?

The plane will take off.

I'd like to pose a slightly different question: Could you launch a plane (engines not running, wheel brakes firmly applied) by using a perfectly flat and extremely long conveyor belt?

Originally Posted by ramblingboy42

I think the only people who believe it will , are those who do not know the theory of flight and the difference between airspeed and groundspeed.

Provided the friction in the wheel bearings is minimal (and what is the point of a wheel bearing and a non driven axle if this is not true) then the plane will take off under all conditions of conveyor movement, even if the conveyor is running so fast that the wheels of the plane are rotating backwards as the plane itself is moving forwards under the thrust created by its propeller.

The only reason the plane moves at all when the conveyor moves is due to friction. When the friction is broken in the wheel bearings the plane is free to move in the direction of any force applied to it.