On Mon, 27 Apr 2009 11:58:30 +0100, Chris Reed
wrote:


*Never* winch launch with wet wings, as this could lead to a stall and
spin off the wire. I wouldn't aerotow with anything more than mildly
damp wings either.

My experience with wet wings (DG-300 and PIK 20B) when winch launching
is that the droplets disappear from the wing surface long before you
enter rotation and to all intents and purposes the launch is normal.
Both above-mentioned gliders had a well polished surface finish
though. I've also aerotowed on many occasions with wet wings -
"operations normal" at 60-65 kts airspeed.

In cruising flight there is a tendency to fly fast to "blow" the wings
free of water - this tends to be counter productive and I've settled
on 60-65 kts as the optimum for my PIK 20B. I estimate about a 20%
reduction in L/D with wet wings. Simply allow for a nominal 40:1
dropping to 32:1!

Geoff Vincent
Melbourne, Australia