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Old December 27th 07, 02:45 PM posted to rec.aviation.piloting,rec.aviation.aerobatics
Stefan
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Posts: 578
Default spins from coordinated flight

Dudley Henriques schrieb:

There is only one thing you have to know about spins. To enter one you
need 2 things to be present; stall and a yaw rate. All the rest is
simply stating different ways to make these two things happen.


While I agree that this is a correct and simple recipe and therefore
quite useful in practice, I don't agree that it helps to *understand*
the situation, because *reason* for the spin is not the yaw rate. The
reason for the spin is an asymmetric angle of attack, i.e. one wing is
more stalled than the other. Of course this situation can only occur if
there is some yaw, which leads us to the recipe given above.

Recipe: As there is always some yaw in a coordinated turn (otherwise it
wouldn't be coordinated), you can perfectly enter a spin from a
coordinated turn. Aerodynamic reason: The inner wing has a higher angle
of attack than the outer, so it stalls first or, if both wings stall, it
is more stalled. Asymmetric stall condition - spin.