It treats the propeller blades as rotating wings with a rather peculiar
angle of attack. Thrust appears as negative drag -- which, although
admittedly eccentric, is one reasonable way of looking at it. I guess
torque would appear as rolling moment. As I say, I haven't made any use
of it in the context of propellers. It does take spanwise flow, tip
losses, etc into account.

Weren't the first all-composite airplanes sailplanes?

Peter