Quote from: Eggtastico

When you run on a Treadmill do you feel a breeze across your body like you would when not running on a treadmill.

Surely its not creating any pressure for air to flow over the wings & generate lift?

Same thing as the car though, lift your feet off the floor and you go nowhere anyway. How many times do we have to point out that jet engines dont push against the ground?

Size of plane makes no difference. A model plane on a big belt would have the benefit of the belt pulling air along towards it so it might be able to take off while remaining stationary.

I havent said they push against the ground. Surely if everything was going at an equal speed, then plane would be motionless? So there isnt any Airflow being created (except maybe a small bit at the wheels) to create Lift..

1st Law of Motion
If an object is not moving, it will not start moving by itself.
If an object is moving, it will not stop or change direction unless something pushes it.



Can someone glue some wings to a Hamster & see if he takes off?

can someone please lock this thread, I am rapidly loosing my belief in the intelegence of some people around here.

This was a bloody stupid question in the first place. The most important flaw with it is that the conveyor which the problem postulates is impossible


For ease of thinking, we ignore the possibility of the tires exploding, conveyor snapping, the bearings siezing and any of 100 other things which would happen very quickly if you tried to do this. To prevent these things from happening, there must be no friction in the bearing/tire/conveyor system except that which maintains the wheels turning at the rate of the conveyor plus the speed of the aircraft.

The jet engine is pushing the plane forward. This provides a thrust of several tens of thousands of pounds.

To prevent the aircraft from moving forward, an equal and oposite force would need to be exerted. It cannot be exerted through the wheels and bearings since there is no friction, and no other backwards force is stipulated in the question. Therefore there is no restraining force, therefore in accordance with Newtons Laws of Motion the aircraft will move forwards, gain lift and take off.

Furthermore, since the aircraft is moving forwards, no matter what you do to the conveyor the speed of the wheels will always be the speed of the conveyor plus the ground speed of the aircraft.  The postulated conveyor violates the laws of physics.


Here speaketh an MSci in Physics, now please stop talking about this total pile of horse manure.

Think thats going to be the only answer as I cant be arsed to read through all the drivel I missed reading earlier