Very nice mid-winter threads on spinning gliders. I'll bet a lot of people
will be a bit more careful this spring. Now, for a very easy way to
inadvertently spin a racer from an aggressive thermal entry.

Assume you are cruising between thermals at a lower than desired altitude.
It's early Spring and you know thermals are small and you need one badly.
Then you feel a bump and the vario beeps.

Because you know the thermal diameters are small on this day, you
aggressively pull up and simultaneously turn toward what you hope is the
core of the thermal. You mix rudder and aileron inputs carefully to keep
the yaw string centered but your mind is on the vario and traffic lookout.
Your guess about the direction is right and you sense you have entered the
core so you tighten the turn. A lot is going on here as you pull, trim and
re-set the flaps with your hands.

You forget or maybe you are just too slow to release the large rudder input
that you have held since starting the thermal entry. Your feet are far from
your brain and respond much slower than your hands. With the rudder
deflected to the lower wing, the bank keeps steepening. Concentrating on
keeping the glider in the thermal, you respond with top aileron to stop the
increasing bank and with more back stick to keep the nose on the horizon
where it belongs... Then, the glider snaps into a spin out the bottom of
the turn.

All that is required for this scenario is a late release of the initial
rudder input.

Bill Daniels