On 20 Mar, 01:00, Bob Cook wrote:
Ian,

I was trying to point out a misconception that the "horizontal component
of lift" in a turn is somehow balanced by some other force.

If it were, the glider would not turn.

It all depends on your reference frame. To someone on the ground, an
unbalanced sideways force gives rise to the necessary acceleration.
But to an observer moving with the glider - the pilot, say - there is
no sideways acceleration /of the glider/ (the rest of the world may,
of course, be doing something). To the moving observer, an equal an
opposite centrifugal force provides the necessary balance.

We engineers like modelling with moving reference frames and
centrifugal forces because it turns dynamics problems into statics
problems, which are generally simpler. Physicists, and particularly
school physics teachers, traditionally get terribly upset by the idea
of centrifugal force.

Ian