Udo Rumpf wrote:
I am always surprised when I read comments about sensitivity to rain
or water and I agree water that pearls on the wing surface will have
a negative effect on "all airfoil shapes". When was the last time you flew
through rain and where it mattered in regards to getting home or not.
Either one is cut off and one has to land in any case or one escapes
a light and short duration shower and waits it out. I have no interest
in how my airfoil performs when exposed to water.

In my limited experience, you are generally correct. But the PIK20b in
my experience is *particularly* sensitive to water.

I flew the PIK in a number of eastern US contests. We didn't fly in
much rain but one particular encounter in the mid-80s captured my
attention. I pulled up into a thermal just as a light sprinkle of rain
hit. I stalled out of the pull up! This is the only time I can
remember stalling accidently in any conditions.

It didn't at first occur to me that the rain and the stall were related
but it soon became apparent that I wasn't flying the same sailplane I
was flying before the rain.

I didn't make it home that day and landed at an airport. The anemic
Citabria was sent from Dansville to pick me up at Grand Canyon airport
(NY State). We started the tow just as another light sprinkle fell.
The Citabria lifted off in its normally anemic way but I couldn't get
the unballasted PIK off the ground. I rolled off into the grass at the
end. Anyone familiar with Grand Canyon (in the mid-80s) knows the
reason for the name. Fortunately the ground falls away quickly and I
became airborne.

I would suggest that the PIK is a notable exception to your conclusion.