As a sidebar to this discussion I noticed one person posted that he is
constantly on the edge of stalling his glider during thermaling. I would
argue that he is flying very inefficiently if that is in fact the case. To
convince yourself try thermaling (when alone) at the buffet speed vs adding
5-10 kts at differing angles of bank and focus on the VSI and see what the
results are. Look at any polar as well.

Casey Lenox
KC
Phoenix

I haven't seen polars that take into effect bank angle, but
from doing the calculations of turn radius and angles of
bank, I'm convinced that in very long wing gliders at
high angles of bank and slow speeds (and ergo light weights too),
the inner wing is significantly slower than the
outer wing, and tacking on some knots is most
efficient (to keep the length of the inner wing nicely above stall)...

Mark Boyd