Can a Plane on a Treadmill Take Off?

What is keeping the airplane's speed up with the conveyor belt? The
propeller. Said propeller moves air. Air causes lift. The problem is
more complicated than it seems to be at first read.

"Doug" wrote in message
oups.com...
What is keeping the airplane's speed up with the conveyor belt? The
propeller. Said propeller moves air. Air causes lift. The problem is
more complicated than it seems to be at first read.

Another way to say it; it had better be a long conveyer belt, cause the prop
is pulling the plane forward, without caring how fast the wheels are going.
That will make the necessary airspeed to lift off.
--
Jim in NC

experiment, go run with a kite(in a no wind situation) untill it flies,
measure the speed youre running. get on a teadmill and run that speed
that it took to make the kite fly. does the kite fly when youre on the
treadmill? no... same thing as the airplane on the conveyor belt. i
know i said i was done but i cant keep my hand out of this.
jester

I dont know what all the fuss is about. The plane will not takeoff for
the reason that the all the plane is doing is keeping stationary. In
actual fact the trust thats produced is not producing thrust, its only
compensating from the drag thats pull the aircraft back. (treadmill) in
order to take off the plane must superexceed the opposing force and
establish that trust actually does exceed drag. hence the the plane
must build up momentum (in the correct direction)

correct ?

Barry...

Ok, in relevance to Dougs post... we are both correct !!! apart from
the down wash from the small propeller, they will not be any airflowing
over the rest of the wings... why ??? Because the airplane is not
moving !!!! its only compensating for the exstreem backward force, as i
said its only standing still, and standing still doesnt get you
anywhere. you need momentium.

It however, would be possible if you have a plane with an exceedingly
small wing span, very low stall speed and a big propeller to generate a
downwash to cover the entire wing. As you know your aillerons are
situated at the outer section of the wings, if you have no downwash
over them it will stall and not turn leading to a temporary lift and
then crash.

Barry

See Custer Channel-wing [Google] and reaction controls.


"The Flying Scotsman" wrote in
message
ups.com...
| Ok, in relevance to Dougs post... we are both correct !!!
apart from
| the down wash from the small propeller, they will not be
any airflowing
| over the rest of the wings... why ??? Because the airplane
is not
| moving !!!! its only compensating for the exstreem
backward force, as i
| said its only standing still, and standing still doesnt
get you
| anywhere. you need momentium.
|
| It however, would be possible if you have a plane with an
exceedingly
| small wing span, very low stall speed and a big propeller
to generate a
| downwash to cover the entire wing. As you know your
aillerons are
| situated at the outer section of the wings, if you have no
downwash
| over them it will stall and not turn leading to a
temporary lift and
| then crash.
|
| Barry
|

even cjcampbell's version of the question and the poster at the web
site are different. if it sits on a conveyor belt that moves at the
speed the airplane does, then is the belt moving when the aiplane gets
on it, or does it start to move by it self?. if, in that exact
question, the airplane starts to move forward, the belt moves backwards
at an equal rate, but the plane doesnt care, the wheels spin at the
combined speed of the airplane and the belt, the plane keeps moving
forward, off the end of the belt and away into the sunset, it might
take a thousand years depending on the resistance of the wheels(if they
were very resistive i suppose it would move backwards, but then if that
were the case, it would never have moved at all, and everything would
still be stnading still), oops, even if you try to simplify that one,
it doesnt work, oh well... my plane will even jump its chocks if you
try hard enough. are there chocks on the belt... what about tie
downs.... is it made of a really sticky tar? OMGosh, see, everybody is
right, and everyone gets a cookie!!! we can all think for ourselves!
thats what being a human is all about!... all right.... ummm, can
someone turn this thing off so i dont keep wasting avgas trying to get
off this thing?... is it wide enought to turn around so i can get a
boost?... this is fun!

"The Flying Scotsman" wrote:

Ok, in relevance to Dougs post... we are both correct !!! apart from
the down wash from the small propeller, they will not be any airflowing
over the rest of the wings... why ??? Because the airplane is not
moving !!!!

Reread the stated problem:

"a conveyer belt that moves in the
opposite direction at exactly the speed that the airplane is moving
forward."
Seems a pretty direct contradiction to the claim that it is not
moving. In fact, it very explicitly says that the plane is moving
forward, and at the same speed as the conveyor. So when the conveyor
is moving at takeoff speed, so will the plane, and the sound of the
tires will be that of a plane moving twice takeoff speed (the speed of
the plane relative to the conveyor.

its only compensating for the exstreem backward force, as i
said its only standing still, and standing still doesnt get you
anywhere. you need momentium.

It however, would be possible if you have a plane with an exceedingly
small wing span, very low stall speed and a big propeller to generate a
downwash to cover the entire wing. As you know your aillerons are
situated at the outer section of the wings, if you have no downwash
over them it will stall and not turn leading to a temporary lift and
then crash.

Barry

--
Alex -- Replace "nospam" with "mail" to reply by email. Checked infrequently.

man this post took off like a rocket. a rocket? would a rocket get off
the conveyor?... hmmm, who cares! but it is a great mental workout...
anyone who comes up with an answer has made assumptions. but we have to
assume things in order to live, you have to believe that when you take
that next step that the ground will be there. in schrodingers cat(sp?)
the cat both lives and dies. in our world that cant be at the same
time.... its like minority report... this q is similar in a way to the
cat in the box with the poison with the degrading material. it can be
both ways, depending how you look at it. quit debating and go pet a
dog!

"alexy" wrote

Reread the stated problem:

"a conveyer belt that moves in the
opposite direction at exactly the speed that the airplane is moving
forward."

All it is, is a trick question, aimed at testing your reading and
comprehension ablility. The plane moves off in exactly the same manner as
on a regular runway. The moving belt is a distracter.
--
Jim in NC