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  #114  
Old June 16th 05, 07:58 PM
Peter Duniho
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"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.

[...]
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.

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.

[...]
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. Your previous claim (quoted above) was that you COULD
stall while flying parallel to the ground. That is, one could "stall
'flat'".

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.

[...]
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.

[...]
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.

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.

I'll say it again: the scenario you propose is an impossibility.

Pete