I don't have the full context from the quote above, and while I am
normally loathe to contradict Langewiesche, I must report I have
successfully produced turns with just the rudder in gliders. Give it a
try, and you will find you can produce an adequate turn, because the
yawing causes the dihedral to bank the glider in the desired direction.

I suggest you give it a try at or near the stall...

(Only in america would we come across such a technique even being
discussed!)

And only on the world wide web would an American assume they were the extent of the actual world.

Bagger
winter in Aus-bloody-stralia mate
:-)