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  #89  
Old August 28th 04, 04:31 PM
Chris OCallaghan
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Marc,

Per earlier discussions, the spin is avoided by coordinating rudder
with aileron input. The stall is avoided by decreasing angle of
attack. Yes, aileron input will increase angle of attack at the tip,
but in modern sailplanes, if you use an equal deflection of rudder,
even on the cusp of a stall, a certified aircraft will not spin. Of
course, this ignores other variables, and there's nothing like a few
extra knots (read lower AOA) to keep things manageable. But we really
should start discarding some of the old axioms. Or at least replacing
them with more accurate ones.

Let me give you an example for the sake of continuing the discussion
on an interesting tangent. You are very close to the ground, turning
base to very short final. In a twenty degree bank, you sense your
speed has decreased and your bank is suddenly steepening. You fear
that your wingtip will touch the tree tops before completing the turn.
What do you do?

Think this one through. According to an axiomatic approach, you make
no aileron input because your fear entering a spin (or your muscle
memory keeps you from doing it). Lowering your angle of attack means a
momentary increase in sink rate. Kicking the rudder exclusively will
also increase your sink rate, even if manages to slow or stop your
roll momentarily.

There's only one effective solution.

Maybe we should spawn a new thread.

Cheers,

Chris