Can a Plane on a Treadmill Take Off?

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.

In article .com,
"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.

He's right.

rg

Only if you make many assumptions. Otherwise, he's wrong. The only
correct answer is "unknown" because of lacking information. The only
way to get off of, "unknown", is to make assumptions, which Cecil
happily did. Therefore, if he's allowed to make assumptions, so are
the rest of us. Which means, the answer is equally, "no".

Either way, he's wrong because he made an assumption or he's wrong
because we are allowed to make assumptions in the other direction,
thusly proving he's wrong.

"Greg Copeland" wrote in message
ups.com...
Only if you make many assumptions. Otherwise, he's wrong. The only
correct answer is "unknown" because of lacking information. The only
way to get off of, "unknown", is to make assumptions, which Cecil
happily did. Therefore, if he's allowed to make assumptions, so are
the rest of us. Which means, the answer is equally, "no".

Either way, he's wrong because he made an assumption or he's wrong
because we are allowed to make assumptions in the other direction,
thusly proving he's wrong.


Bull. The only unknown is the amount of friction due to rolling resistance
of the tires and wheel bearings. Give me that and I'll give you the takeoff
distance.

Ok, so all of us do not comment on his site, or well maybe that would
be better, does this guy really not have any sense to know that the
ground speed is completely irreleveant to aerodynamics(thinking of the
threads about 152s with 0 or negative ground speed)? whatever....
airspeed is zero, no lift, no fly.
Jester

In a previous article, "jesse" said:
Ok, so all of us do not comment on his site, or well maybe that would
be better, does this guy really not have any sense to know that the
ground speed is completely irreleveant to aerodynamics(thinking of the
threads about 152s with 0 or negative ground speed)? whatever....
airspeed is zero, no lift, no fly.

Hopefully the people commenting on his site aren't as stupid as you.


--
Paul Tomblin http://xcski.com/blogs/pt/
#define sizeof(x) ((int)rand()*1024)

Paul Tomblin wrote:
In a previous article, "jesse" said:
Ok, so all of us do not comment on his site, or well maybe that would
be better, does this guy really not have any sense to know that the
ground speed is completely irreleveant to aerodynamics(thinking of the
threads about 152s with 0 or negative ground speed)? whatever....
airspeed is zero, no lift, no fly.

Hopefully the people commenting on his site aren't as stupid as you.


Paul...dont look now, but that airplane is NOT flying off the ground
until the AIRSPEED is up...the treadmill is only moving the TIRES, that
means diddly squat to an airplane.

Damian

My friend and i were discussing this. There is not enough information
in the orginal question to determine anything. Depending which way you
argue the various variables, it could work either way. The people who
are saying the plane will fly are saying that the prop pushes against
the air and thus will eventually fly, the people who are saying that
the plane will not fly are assuming that the prop(or jet) is only
giving enough thrust to equalize the resistance on the wheels bearings
etc, thus the plane will stand still. define some variables, define
speed(wheel speed, ground speed, air speed) the original poster(at
cecils site) didnt give us enough info, and used the term speed and
move in more than one way. he also a plane standing on a runway, then
it moves, but then the conveyor moves. which is it buddy? if the plane
starts to move, it will take off. uh oh, here i go again, getting lost
in the details, now i think it will take off. its almost akin to
asking, if you fire a gun into a crowd will you kill someone. a lot of
people would say yes. what if the bullet went between people, what if
it was a blank, what if it was a blank and then some guy had a heart
attack, what if superman stopped it. define variables and argue it
either way, the answer is yes and no, it depends, and thats the
wonderful thing about these questions, it gets us to think, thats why
we are the top of the food chain. animals might have said, i dont care
weather it takes off or not, im outta here so it doesnt eat me. other
animals might have tred to eat it. aluminum or wood or fiberglass or
steel is not very edible to us, so we talk about it. its a great world
isnt it! if you need to be right to prove your intelligence, go on
jeopardy. to me, i gotta go flying, and i havent seen any conveyor
belts at OUN, so im outta here!
Jester

"jesse" wrote in message
oups.com...
My friend and i were discussing this. There is not enough information
in the orginal question to determine anything.

I think jesse has earned his way into my "not worth the effort" file.
Anyone else have him strike you that way?
--
Jim in NC

"Damian" wrote in message
...
Paul...dont look now, but that airplane is NOT flying off the ground until
the AIRSPEED is up...the treadmill is only moving the TIRES, that means
diddly squat to an airplane.

Damian, don't look now but Paul is exactly right (except for his rude
nature, of course).

The treadmill is irrelevant to the airplane's motion. If the airplane is
stationary on the treadmill, it's because it has a headwind the same speed
as the treadmill and enough thrust to fly into the headwind at the same
speed as the treadmill. Of course, the wheels will be turning on the
treadmill, but only because the treadmill is rotating them against the
air-based stationary nature of the airplane.

Without a suitable headwind for the airplane to fly into, the treadmill
would just push the airplane backward. Airplanes don't use their wheels for
transmitting power to forward motion (most don't, anyway ).

Pete