ASW-20 spins

I was much more lucky in my ASW-27 at 70% CG when I had a windshear induced
stall while moving to flap L at ~300 above threshold. I lost 269' and was
fortunate to recover over lower ground before having to dodge a topsoil
pile in the neighboring gravel pit.

With headwind component = TAS - GS, the flight data shows 3 windshears,
each over a 2 second interval, of -17, +23, -28 kt (application of
Pythagorean sum of squares of a triangle on the final shear yields 6 kt of
apparent headwind giving -34 kt -- TWICE the recorded wind).

Recovery action was flaps negative and stick forward.

The usual stall practice at 3000 AGL with a 1 kt/second deceleration has
little resemblance to a low level windshear stall.

More details on:

https://www.dropbox.com/sh/lq9osn15b...wuYvScXya?dl=0

I watched one of those early ASW 20 fatal spins. It was from slow
straight
=
and level flight, not thermaling. The wing dropped sharply and the glider
e=
ntered a conventional, nose-down spin. The recovery began almost
immediatel=
y (approx. 1/4 turn) but unfortunately there was not sufficient altitude
(t=
his began at approx. 300 ft AGL) and the pilot was killed when the glider
i=
mpacted the ground slightly nose down (i.e., the recovery was almost
comple=
te) but still sinking. Undocumented tail ballast was probably a factor,
as
=
with UH's situation. Pilot incapacitation due to dehydration may also
have
=
been a factor. The final blow, so to speak, was the lack of a headrest in
t=
his very early '20 and a battery pack behind the head that came loose.
The
=
pilot was an experienced, high-time competition pilot and instructor. All
o=
f the contributing factors were avoidable.

Chip Bearden
ASW 24 "JB"
U.S.A.