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Travis Marlatte wrote:

Why isn't there forward motion on the treadmill? The pressure
differential
around the prop or the thrust from a jet will propel the plane forward
to
takeoff speed on glare ice (wheels don't have to spin at all) or the
treadmill (wheels spin at twice the speed).

The Original Question said that the treadmill speed was such as
to counter wheel speed so that the airplane stood still. That's what I
was thinking. Somewhere along this thread the assumption must have
changed and I'm arguing apples against oranges.
No airspeed, no lift. Period. Propeller or jet blast is not going
to lift the airplane. We need forward motion relative to the
atmosphere, or a really strong headwind.

The tires used on light aircraft are Type III and are rated for
120 MPH max. They'd probably explode before 150 MPH, seeing that the
forces increase by the square of the rotational velocity. Or. more
likely, the average lighplane tire being as out-of-round and imbalanced
as it is, the vibration would shake the airplane apart by the time we
got to 120.

Dan

I am not sure what sort of perversity is causing me to continue reading this
insane thread, much less respond to it.

Here is a copy of the text, lifted from the New York Times web site as
linked; except that I have edited out the special characters which appeared
as a result of the text conversion:

-----------begin NY Times excerpt---------

December 11, 2006, 4:37 pm
The Airplane-Treadmill Conundrum
OK, this 's driving me crazy. This brain-teaser is ripping around the
Internet, plus I actually overheard it THREE TIMES in airport conversations
on a recent trip to Canada.'s how I found it presented at
http://boards.straightdope.com/sdmb/...d.php?t=348452 Imagine a plane
is sitting on a massive conveyor belt, as wide and as long as a runway. The
conveyer belt is designed to exactly match the speed of the wheels, moving
in the opposite direction. Can the plane take off? I say no, because the
plane will not move relative the the ground and air, and thus, very little
air will flow over the wings. However, other people are convinced that since
the wheels of a plane are free spinning, and not powered by the engines, and
the engines provide
thrust against the air, that somehow that makes a difference and air will
flow over the wing. The guy behind me at the airport told his buddy that,
in fact, the plane WOULD take off, and his buddy seemed to agree. Do we have
any physicists in the audience?

---------end NY Times excerpt-------

Please note that the embedded link still works.
Please note also that nothing new can be added.

I submit that there are really only two logical presumptions, both of which
have been explored:
1. The aircraft will take off normally.
2. The magic treadmill has no inertia and no limiting speed; and, by some
unexplained means, can sense the rotation of the wheels. Therefore, if the
aircraft is placed very near the departure end of the runway and connected
to an airport tug which is placed on solid ground; then, as the tug begins
to slowly pull the aircraft forward, the magic treadmill will quickly
accelerate until the wheels and tires of the airplane have catastrophically
failed.

I further submit that the second presumption is ridiculous.

Peter