How many gliders can be trimmed for hands off thermalling?

An instructor showed me, with spoilers open and proper
trim, the glider will stabilize in a slow descending
turn. Claimed it was good for getting out of a cloud.

You're talking about two totally different things here. One is thermalling,
the other is the benign spiral mode (what your instuctor did with you....good
instructor!).

The way I teach the benign spiral is trim for 60 kts and don't touch the stick.
The plane will speed up and slow down and turn, but should always stay within
limits. As you said, it is useful if caught in cloud. Spoilers deployed is a
new one to me.

Jim Vincent
CFIG
N483SZ
illspam