"Bill Denton" wrote in message
...
You are both right and wrong on this one.

No. I am entirely right, not wrong at all.

Obviously, different parts of an aircraft stall at different speeds.

This is true, but completely irrelevant to my statement.

[...]
You then take an airplane to 1,000 ft AGL, and trim it so it is flying
perfectly straight and level, but this time you completely close the
throttle. In a short time, the wings will stop producing enough lift to
keep
the airplane in flight, it will pitch down and impact the earth, even
though
some of the airplane's component parts may still be flying.

First, your scenario is completely incorrect as to what would happen if you
brought the throttle to idle. The airplane would NOT stall. It would
simply pitch down enough to maintain the trimmed airspeed, and glide to
whatever final destination it was aimed at.

But more importantly, your understanding of a stall is flawed. Even simply
looking at just the wing, and even ignoring such design features as washout,
upon reaching the critical angle of attack lift does not go straight from
maximum available lift to 0. There is a very narrow range of angle of
attack where the lift drops off rapidly, and within this range, there is
just as much lift as was available at angles of attack just below the
critical angle of attack.

For a variety of reasons, it's unlikely that a pilot would ever successfully
negotiate this very narrow range. But it does exist, and a person who
claims that a wing is strictly "not stalled" or "stalled" is simply
demonstrated lack of completely knowledge of what happens during a stall. A
stall is more like a dimmer light switch (with a very short throw) than it
is like a regular "on/off" light switch.

[...] I think it is also evident that I do understand at least the
basic principles involved in the discussion.

Very basic principles. But you still have quite a ways to go. You might do
well to stop telling people they are wrong, at least until you've actually
*mastered* the subject.

But please assume an airplane, accept my terminology, and consider the
following:

If a wheel is rolling, you cannot start it rolling.

My statement was: " If the airfoil is flying you cannot take off, and if
it's not flying it's stalled", which would translate as follows: "If the
airplane IS flying it cannot START flying"' the rest reflects the
flying/stalled paradyme, which I readly admit is not absolutely correct.

So you really did mean to write "if the airfoil is flying you cannot take
off". I've got to say, that's got to be one of the most intentionally
obtuse ways of saying something I've seen in a long time.

In any case, you are simply incorrect to say "if it's not flying it's
stalled". That is a patently false proposition. I have an airplane sitting
in my hangar right now that is not flying (at least, it had better not be!),
but it is not stalled either.

Actually, it was the original poster who failed to define "flying" and
specify what was flying. As noted above, I am looking at this in the
context
of an entire airplane, which seems to have been the original poster's
intent.

Another red herring. It really doesn't matter whether you are talking about
the entire airplane or the wing. But for the record, when one refers to a
"stall", they are generally referring to a stall of the main wing (and by
implication, the entire airplane).

In fact, the airplane doesn't need to move on the runway at all;
given a sufficient releative wind, parts of the airplane would begin to
fly
without the airplane moving forward at all.

I thought your claim was that an airplane that was flying (and thus
presumably parts of an airplane that are flying) cannot take off. Now you
are saying parts of the airplane can fly while still on the ground. Your
statements are inconsistent with each other.

And given a relative wind even
slightly higher than the stall speed of the aircraft, it could
theoretically
take off and continue to ascend with no forward movement.

No, it could not. With a strong enough wind, the airplane might lift off
the ground, but it would immediately begin to slow within the airmass
(accelerating backwards relative to the ground) and descend back to the
ground. There would be no "continue to ascend" about it.

I agree with your definition, but it has to be consiered in light of
whether
we are discussing a single element or an entire airplane.

We are discussing the wing, which is the only thing of interest in this
case. If you want to call that "the entire airplane", that's fine too, but
make no mistake: it's still just the wing.

If an airplane is only moving at 1
kt. down a runway, it is probably not flying.

Again, you'll have to define "flying". But the wing certainly is
developing
lift, and certainly is NOT stalled.

How 'bout if I throw in a 10 kt tailwind? g

If you want to change the discussion in an attempt to make your comments
make sense, feel free. I probably won't have the patience to bother though,
and will simply feel justified in assuming that you aren't really interested
in learning what the facts are.

I recommend you stick with the original ideas, and where you've clearly
meant "1 knot of relative wind" by saying "if an airplane is only moving at
1 knot down a runway", you should avoid complicating things by trying to
reinterpret what you've written.

Simply untrue. Virtually all of my landings involve touching down and
coming to a stop without ever exceeding the wing's critical AOA. I
hesitate
to claim that I've *never* stalled the wing during a landing, but I sure
don't do it intentionally.

And this comes back to the flying/stalled paradym.

The word is "paradigm". And frankly, I have no idea what you mean by "this
comes back to". This thread *should* have stayed with the question of a
stall all along. Only your digressions have prevented that.

The bottom line here is that your statements that "you can't take off
without a stall" and that "an aircraft will not land until it has reached a
stalled state" are both patently false. You can very much both take off and
land without ever stalling the airplane.

Pete