"Montblack" wrote in message
...
("Michael Ware" wrote)
You are taking the statement 'a conveyer belt that moves in the opposite
direction at exactly the speed that the airplane is moving forward' to
mean that somehow there is a force being applied to the mass of the
aircraft, equal and opposite the thrust generated by the propellor. The
only place the treadmill can exert any force an the airplane is the only
place the treadmill is touching the airplane: the wheels. Any motion of
the treadmill belt will be translated into rotation of the wheels. This
will not prevent the aircraft from moving forward, through the air and
taking off.

That's one of the best so far.


THE AIRPLANE WILL NOT MOVE. (That's my vote)

The rotating wheels + gravity (Thank you Sir Isaac!) ANCHOR the plane to
the
treadmill. Plane/prop move forward, treadmill/wheels fall back. The plane
is
attached to the wheels. Try it in front of you with a ruler and a magic
marker.

That airplane is doing 150 mph down that runway, only the runway is really
a
treadmill which is matching that speed. End result is = to an Olympic
sprinter on the same treadmill - I can stand next to him for his entire 10
second (27 mph) race.

Lordy. BDS answered this pretty well. But, imagine that the plane is held
still by a rope secured in front of the conveyor. That rope is attached to
a strain guage that measures the force, in kg, say, that the moving conveyor
exerts on the plane. This will increase with the speed of the conveyor, but
let's use a reasonable number and we will see that the force is minimal
since it's only whatever is converted to heat in the wheel bearings.
Probably less than a few hundred watts. The amount of power required to
move the plane forward will be more than required on a stationary runway by
only this much. Dig?


Montblack 83.7
(I thought some of double-digit people needed to be heard from. g)

moo

www.mensa.org