On Saturday, January 11, 2014 1:35:45 AM UTC-6, Chris Rollings wrote:
If you are gliding from one thermal to another, optimum speed is the same
whether you are going into wind, downwind or no wind, it just depends on
the rate of climb achieved in the next thermal. If you are gliding to a
point on the ground, final glide or round a turn-point, then optimum speed
will be higher into wind than downwind.


Not quite true on final glide. If you're in a 3 knot thermal, you climb until you hit the Mc 3 glide height, and then set off at the Mc 3 speed to fly, and the wind makes no difference to this calculation. It does not make sense to sit in a Mc 3 thermal, drifting downwind, to get higher and then bash home at the Mc 4 speed just because it's in to the wind.

This presumes that the goal is speed, not stretching a glide.

This also ignores the fact that it's often easier to bump thermals into the wind, but much harder to scratch low going into the wind than downwind. Those features argue for a bit more aggressive approach early on an into-wind final glide, and a much more conservative approach later on an into-wind final glide. All my final glide disasters have been going in to stiff winds! When down to 1000 feet, it's awfully nice to be drifting downwind while you hunt around in those half know thermals.

John Cochrane