Can a Plane on a Treadmill Take Off?

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

"Morgans" wrote in message
...

"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?

Jesse needs to learn how to capitalize, punctuate, and separate his
sentences into paragraphs in order to make his posts readable.

Jesse needs to learn how to capitalize, punctuate, and separate his
sentences into paragraphs in order to make his posts readable.
\
Yep. That would be a very good start. There is more to it than that,
though.
--
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

Peter, I think you lost the relative perspective. Given the original riddle,
the treadmill only moves backward at the same rate the plane moves forward.
If the plane was developing exactly enough thrust to counteract the
headwind, it will not move and neither will the treadmill.

--
-------------------------------
Travis
"Peter Duniho" wrote in message
...
"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

"Travis Marlatte" wrote in message
hlink.net...
Peter, I think you lost the relative perspective.

No, I didn't.

Given the original riddle, the treadmill only moves backward at the same
rate the plane moves forward.

The rate at which the treadmill moves is entirely irrelevant. An airplane
does not transmit any force through it's wheels. They simply rotate
whatever speed is required to account for whatever speed the airplane has
relative to the surface the wheels are in contact with.

It doesn't matter one bit WHAT speed the treadmill moves, according to the
original riddle or otherwise.

If the plane was developing exactly enough thrust to counteract the
headwind, it will not move and neither will the treadmill.

The headwind is just an example. The actual wind could be anything. Yes,
if the headwind is exactly the same speed as the airspeed, the airplane
won't move. My only reason for setting the headwind equal to airspeed, as
an academic point of reference, is that if it's not, the airplane isn't
going to stay sitting on the treadmill for very long, making the "riddle"
even less interesting.

Pete