> So thats what you get, a dramatic change one or the other way in pitch
> required to stall at a given speed when extending one or the other.
This is as I (now) understand both the insistence that a correct AoA
(lift coefficient) calculation requires recalibration with flap setting
and the satisfactory operation of stall warners irrespective of flap
setting.
It all depends what you want to accomplish:
1. Whole wing
The whole wing gets a new lift coefficient (defined as lift per dynamic
pressure in some units or other) when it changes shape. The wind angle
for zero lift for the whole wing changes for instance when the chord
line changes. So a new translation from geometric angle to aerodynamic
angle. I agree on that.
2. Stall of a critical section
A flapless wing section stalls at a certain (geometric) relative wind
angle, whatever the rest of the wing looks like. The same is probably
true for the fixed leading edge of a flapped section. For a stall
approach warning the lift/angle properties of the whole wing are not
relevant as long as the sensor measures the geometric relative wind
angle of a critical fixed piece of wing. Critical is the operative word:
if this stalls then all stalls (I wonder if for a wing with LE slats
such a representative fixed piece of wing exists).
Does this sound reasonable?
Jan de Jong
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