Recently, Peter Duniho posted:
"Neil Gould" wrote in message
...
[...] So, in context, how is your theoretically available lift
relevant?
It is relevant only to your false claim that a stalled wing provides
no lift. Had you not made that false claim, I would have had no
reason to bring up that element of the discussion.
The only falsity here is your claim that I made such a statement. So,
apparently you have no reason to bring up that element in the discussion.
What I *did* claim is:
"You're holding the aircraft at just above the stall speed. When you're
stalled, you're falling, not flying."
This makes *no* reference to the amount of lift that a stalled wing
provides beyond it being inadequate to support flight, which should be
obvious to one who pays so much attention to details as you.
[...]
To be a scalar, it would have to lack motion, ergo no "attack".
Wrong. "To be a scalar" it needs to be a single value. And it is.
Angle-of-attack is just an angle. A single value.
Wrong. A scalar can not contain elements of direction by definition. Ergo,
AOA has no meaning as a scalar.
Every angle requires two reference lines in order to define that
angle. That doesn't change the fact that the angle itself is a single
value, without any direction component. Likewise, the fact that two
reference lines (one defined by a direction of travel) are used to
define angle-of-attack DOES NOT MAKE ANGLE-OF-ATTACK ITSELF A VECTOR.
It's still just an angle.
Wrong, it's AOA only has meaning when referenced by a direction and
motion. Without that direction and motion, THERE IS NO ANGLE OF ATTACK. If
you still don't understand this, what is the AOA when the aircraft is
parked in the hangar (with the doors closed and no fans running, if you
insist on picking nits)? ;-)
Finally, when you apply a direction to a scalar, what does it become?
;-)
[...]
I responded to that. In the context of landing, if one flies slowly
enough to stall, one can stall "flat" relative to the ground
because the decrease in forward "relative wind" increases the AOA.
That is what my remark addresses.
Your claim is incorrect. As long as the airplane is flying just
above the ground, the relative wind is parallel to the ground. No
change in the angle-of-attack will occur from any decrease in speed,
not directly.
My claim is that if the aircraft is flying parallel to the ground
just before touch-down, it isn't stalled.
That's a new claim.
Wrong, that's my original claim:
Jose: " Then what am I doing when I practice stalls at altitude, holding
the aircraft at the stall buffet?"
I wrote: "You're holding the aircraft at just above the stall speed."
Your previous claim (quoted above) was that you
COULD stall while flying parallel to the ground. That is, one could
"stall 'flat'".
Again, I made no such statement. My above claim is actually a
clarification of my original statement for your benefit.
My "stall flat" comment refers to pitch angle relative to the ground (as
was stated in the same paragraph). I made no claim about travelling
parallel to the runway. Indeed, one would *not* be going parallel to the
ground in a flat stall.
In any case, other than the issue with the geometry of the airplane,
there is absolutely no justification in claiming that flight parallel
to the ground precludes a stall.
I made no such claim as this, either.
[...]
It is simply impossible to do what you suggest one might do. If one
"flies slowly enough to stall", the angle-of-attack is at the
stalling angle-of-attack, period.
And all I'm saying is that this is independent of the pitch angle
relative to the ground.
It is NOT independent of the pitch angle relative to the ground if the
airplane is being flown in a flight path parallel to the ground.
Again, "a flight path parallel to the ground" is *your* assumption, and
not a claim of mine. A flight path parallel to the ground, but with a high
AOA is Todd's assumption, and again not a claim of mine. I have no problem
with these scenarios, they just have nothing to do with what I've written.
[...]
What WILL happen is that as the aircraft slows, the pitch angle of
the aircraft will need to be increased, so as to continually
increase the angle-of-attack of the wing.
We are describing the same phenomena from two perspectives.
I am fairly certain we're not.
I am fairly certain that you are confused about this.
In the context
of my usage, if one maintains the pitch angle as the aircraft slows,
the AOA will continually increase (normally, the pitch angle changes
as the aircraft slows).
You cannot "maintain the pitch angle as the aircraft slows" without
touching the runway. If the aircraft slows and the pitch angle is
not changed, lift is reduced and the airplane will descend onto the
runway.
That is NOT incongrous with what I've written. The aircraft "descends"
because the AOA increases as the aircraft slows and the pitch angle is
maintained. Do you *really* disagree with this?
I'll say it again: the scenario you propose is an impossibility.
And, I'll say it again, you are confused about what I've written. You've
repeatedly attributed claims to me that I never made, and set up straw men
that have nothing to do with the issue at hand.
Neil
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