"Peter Duniho" wrote in message
...
"Ray" wrote in message
...
Looks like airplane treadmill problem, regularly a spark for flame wars
on R.A.P., has made it into the mainstream.

http://pogue.blogs.nytimes.com/

And handled with every bit as much intelligence and consideration as we've
seen here. Which is to say, there's no shortage of people convinced that
the airplane won't take off, even though it will.

Let the arguing begin!

Why? Haven't you had enough by now?


It seems that the "non-believers" think that the treadmill is somehow
holding the airplane back.
The way that the problem is posed on the blog states that the treadmill
matches the wheel speed of
the airplane. ("The conveyer belt is designed to exactly match the speed of
the wheels, moving in the
opposite direction.") If friction is taken into consideration then one of
four conditions can exist.
1. no thrust (or not enough thrust to overcome frictional forces) ...
neither the plane nor the conveyor are moving.
2. minimal thrust... the wheels and conveyor are moving but the conveyor
drags the plane backwards.
3. just enough thrust to match friction forces... the airplane remains
motionless relative to the earth but the wheels
and conveyor are moving a little faster.
4. more than enough thrust.... the airplane accelerates until it can take
off. The conveyor also accelerates to match
the wheel's speed until lift off when the wheels rotate to a stop and
the conveyor, somehow sensing this, also
comes to a standstill.
The treadmill's speed is dependent on the wheel's speed, not the other way
around.