So...about that plane on the treadmill...

"Darkwing" theducksmailATyahoo.com wrote in message
...
I am a regular on RAP, not a troll.

Then read the extensive thread that we already had on this subject before
you put your two cents in.

Show me video and I will believe it, if the plane is not moving relative
to the wind then the wing isn't making lift.

True.

I have ran on treadmills and I never felt a "wind" blowing in my face.

That's because you're using your feet for propulsion, and the treadmill was
negating your effort. There's no such effect for airplanes, as they don't
use their wheels for propulsion.

Your experience running on treadmills is irrelevant to the question at hand
(except for the intended effect of course, which is to confuse people like
you who haven't thought the whole thing through).

Pete

"Jose" wrote in message
...
A better way to pose the airplane question would be " what would
happen if the airplane is landing on a treadmill that is moving in the
opposite direction and speed?"

How about dispensing with the treadmill entirely. What would happen if
the airplane were on a frictionless surface? The wheels couldn't push on
anything, so how would the airplane take off?

Jose

???

The wheels don't have to push on anything for an aircraft to take
off...there's no drivetrain feeding power to the wheels!

Jay B

The wheels don't have to push on anything for an aircraft to take
off...there's no drivetrain feeding power to the wheels!

Right. Phrasing it the way I did may get people to realize this, or at
least to think about it themselves.

If you put an airplane on the roof of a speeding train, would it take
off? What if the train were shaped like a runway? What if it were very
thin?

They are all ultimately the same question.

Jose
--
"There are 3 secrets to the perfect landing. Unfortunately, nobody knows
what they are." - (mike).
for Email, make the obvious change in the address.

"Jose" wrote in message
. net...
The wheels don't have to push on anything for an aircraft to take
off...there's no drivetrain feeding power to the wheels!

Right. Phrasing it the way I did may get people to realize this, or at
least to think about it themselves.

If you put an airplane on the roof of a speeding train, would it take off?
What if the train were shaped like a runway? What if it were very thin?

They are all ultimately the same question.

Jose

Is that an European Train or an African Train?

:O)

Jay B

Darkwing wrote:
Show me video and I will believe it, if the plane is not moving relative to
the wind then the wing isn't making lift. I have ran on treadmills and I


The problem is, that the aeroplane does move forward, it must, there is
nothing to stop it from doing so.

Imagine (or try)...

1. Hold a wheel between your fingers so it can spin.
2. Put wheel on a treadmill which is not moving.
3. Provide thrust (forward motion) to the wheel from your arm.
4. Observe wheel moves forward.
5. Turn on treadmill, and place wheel on the moving treadmill.
6. Apply SAME amount thrust as you did in 3.
7. Observe same forward movement (discounting the very small friction)
is produced, although the wheel spins much faster.

The thrust acts independantly of the treadmill, you need a treadmill at
least as long as a short field takeoff

http://pogue.blogs.nytimes.com/

If we take the statement, "The conveyer belt is designed to exactly
match the speed of the wheels, moving in the opposite direction", to
mean that the plane can not move forward, because some how the conveyor
is moving so fast the wheel friction becomes great enough that the
engine thrust can not over come it. Obviously this isn't going to
happen, but if it were, I think we can all agree that the conveyor would
be moving extremely fast, several hundred MPH if not thousands of MPH.
Now consider a 150 foot wide, 10,000 foot long conveyor moving at that
speed. Would that not cause enough air to move with it that there would
be enough air speed for the plane to lift off? Of course once that
happened, the wheels would quickly stop, as would the conveyor and the
air. Then with no forward ground speed, the plane would probably fall
because it could not accelerate as fast as the "head wind" was dying.

How's that for an interesting twist?

--
Chris W
KE5GIX

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learn more at http://www.defectivebydesign.org/what_is_drm"

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"Richard Riley" wrote in message
...
[...]
And, just to keep it on topic, the only planes that could take off
from a treadmill are the Osprey and the Harrier.

If you're going to try to stay on topic, you ought to at least try to get
the answer right. At this point plenty of sources, from individuals here in
this thread and the one we had a while back, as well as those cited in the
comments to the blog article referenced, have clearly stated the correct
answer.

Anyone attempting to refute the correct answer, however futile that effort
may be, at least owes it to themselves as well as the rest of us to take the
time to read and understand the references that explain the correct answer.

Pete

("Jose" wrote)
If you put an airplane on the roof of a speeding train, would it take off?


Yes!

The top of the tunnel would (take) the A.C.M.E High Wing Airplane's wings
and rudder section clean (off).


Montblack ....(Beep! Beep!)

In article ,
Jose wrote:

The wheels don't have to push on anything for an aircraft to take
off...there's no drivetrain feeding power to the wheels!

Right. Phrasing it the way I did may get people to realize this, or at
least to think about it themselves.

If you put an airplane on the roof of a speeding train, would it take
off? What if the train were shaped like a runway? What if it were very
thin?

hmmmm, if you put the airplane on, say, a fast moving ship, could it
take off?

I wonder....

--
Bob Noel
Looking for a sig the
lawyers will hate

"Ray" wrote in message
...
Looks like airplane treadmill problem, regularly a spark for flame wars on
R.A.P., has made it into the mainstream.

http://pogue.blogs.nytimes.com/

Let the arguing begin!

- Ray

You're standing on the conveyor wearing a pair of roller skates. The rope
you are holding
is attached to the rear bumper of a truck. The truck is on the ground and
begins to move
away from you. As you begin to move forward the conveyor begins to turn
backwards
to match the wheel's speed. (Here's another point... as long as the wheels
are rolling and
not sliding the conveyor is "matching the wheel's speed". Just depends on
the observer's
reference frame whether the conveyor is moving or even needs to move to meet
the
conditions of the problem.) Eventually the truck will pull you off the end
of the conveyor.
Just substitute a propeller coupled to the atmosphere for the truck's wheels
coupled
to the ground. The conveyor is irrelevant.