Once an LS-3 gets dirty or wet, the performance loss is drastic - the
20 hardly suffers. One clear point pro ASW-20.

Cheers
Andreas

Regarding rain, we discovered the LS-3--like the PIK 20B that was notorious for falling out of the sky when wet--responded well to using a little more flap than usual. All of the gliders that used that airfoil at the time (LS-3/3a, PIK, Mosquito, Mini Nimbus, others) had the same issue and, I suspect, would respond to the same technique.

Another solution that some of us employed was, after the contour/profile sanding, leaving the wing at about 400 grit finish instead of polishing it up.. The water drops didn't bead up so the performance effect wasn't as great. I know one pilot who flew his LS-3 at 220 grit but he joked about having to sand the bugs off.

Speaking of bugs, we don't often have to deal with insects building up on the wing to the same extent as in Europe. So performance in the rain is the concern. I agree the ASW 20 is affected to a much lesser degree.

Chip Bearden