Can a Plane on a Treadmill Take Off?

cjcampbell wrote:
Saw this question on "The Straight Dope" and I thought it was amusing.

http://www.straightdope.com/columns/060203.html

The question goes like this:

"An airplane on a runway sits on a conveyer belt that moves in the
opposite direction at exactly the speed that the airplane is moving
forward. Does the airplane take off?" (Assuming the tires hold out, of
course.)

Cecil Adams (world's smartest human being) says that it will take off
normally.

Assuming the increased tire friction doesn't cause a problem the aircraft
should take off but have twice the normal tire rotation speed when becoming
airborne. That's because the thrust is produced by the prop and it will
accellerate the aircraft into the relative wind. The conveyer belt is just
an entry to confuse the issue. For a car the situation would be completely
different since it produces forward motion by the tires which contact the
moving conveyer belt. The car wouldn't move at all.
--

Darrell R. Schmidt
B-58 Hustler History: http://members.cox.net/dschmidt1/
-

"Darrell S" wrote in message
news:rT6Ff.24873$jR.14387@fed1read01...
[...] For a car the situation would be completely different since it
produces forward motion by the tires which contact the moving conveyer
belt. The car wouldn't move at all.

It might. As "Doug" points out, the presentation is ambiguous as to the
reference point for the speed of the vehicle. If one uses the ground (and
stationary portions of the treadmill) as a reference, then the car would
move, just as the airplane does (it would have to in order to comply with
the description given in the problem), and the car's speedometer would
register a speed twice its actual speed relative to that reference.

Pete

If you tie a 100 foot rope to the tail of an airplane (or some other
part of the airframe), attach it to a good strong post, and run the
propellor up to whatever rpm is available, is anyone claiming the
airplane can then lift up say a feet off the ground?

(Assuming the tail doesn't tear off)

(and, a conveyor belt under the airplane is optional)

Are you saying 1) the rope is tight, or are you saying 2) you are giving the
plane a 100' running start?


"AES" wrote in message
...
If you tie a 100 foot rope to the tail of an airplane (or some other
part of the airframe), attach it to a good strong post, and run the
propellor up to whatever rpm is available, is anyone claiming the
airplane can then lift up say a feet off the ground?

(Assuming the tail doesn't tear off)

(and, a conveyor belt under the airplane is optional)

In article ,
"Michael Ware" wrote:

Are you saying 1) the rope is tight, or are you saying 2) you are giving the
plane a 100' running start?


"AES" wrote in message
...
If you tie a 100 foot rope to the tail of an airplane (or some other
part of the airframe), attach it to a good strong post, and run the
propellor up to whatever rpm is available, is anyone claiming the
airplane can then lift up say a feet off the ground?

(Assuming the tail doesn't tear off)

(and, a conveyor belt under the airplane is optional)

Didn't think of that -- and maybe your response is tongue
in cheek -- but I had in mind "rope is tight".

If you tie a 100 foot rope to the tail of an airplane (or some other
part of the airframe), attach it to a good strong post, and run the
propellor up to whatever rpm is available, is anyone claiming the
airplane can then lift up say a feet off the ground?

(Assuming the tail doesn't tear off)

(and, a conveyor belt under the airplane is optional)

Depends on the airplane, certain lpanes are built in such a way that
they can actually attain enough lift just from the prop wash alone.

The Monk

"Flyingmonk" wrote in message
oups.com...
Depends on the airplane, certain lpanes are built in such a way that
they can actually attain enough lift just from the prop wash alone.

Other than the ones we call helicopters, I've never heard of such a thing.

Care to elaborate?

Other than the ones we call helicopters, I've never heard of such a thing.

Care to elaborate?

Already rephrased my statement.

The Monk

"Flyingmonk" wrote in message
oups.com...
Already rephrased my statement.

Sorry, I missed that. Even having been told it exists, I still can't find
the post with the rephrasing, but I'll assume it essentially retracts the
claim that an airplane can fly from prop wash alone.

On Sun, 5 Feb 2006 00:39:47 -0800, "Peter Duniho"
wrote:

"Flyingmonk" wrote in message
roups.com...
Depends on the airplane, certain lpanes are built in such a way that
they can actually attain enough lift just from the prop wash alone.

Other than the ones we call helicopters, I've never heard of such a thing.

Care to elaborate?


I've been told that a Maule will do that. With a little wind, just
apply power and it jumps into the air instantly. Similarly, in wind
it'll land vertically. But then the Maule pilot who told me this was
from Alaska, where airplanes routinely perform mythic feats.

RK Henry