n5296s:
OK, I see your point now about the angle of the wings in the pitch plane. It's a valid point but in the noise mathematically.
mm_flynn:
I would suggest in this discussion it can be reasonably ignored as well
If you are comparing scenarios, I would include it, but I agree it is probably not a major feature. FWIW with a "L/D ratio" of 8, and a 60 degree angle of bank, I get a theoretical descent angle of about 14 degrees.
Backpacker, you are of course right, there is a vertical component of drag in a descent. In mitigation, sometimes I only come on pprune every few days, and I had missed the earlier thread completely. Sorry for the missed or repeated points!