On Monday, June 17, 2019 at 4:20:46 PM UTC-7, danlj wrote:
Comments below force a response.
1: the most efficient calibrated airspeed for progress over the ground DOES vary with the wind. A published rule of thumb is with a headwind, add 1/3 the headwind component to best glide; with a tailwind, fly at minimum sink.

Not to maximise speed in continuous cross-country soaring from one thermal to another, no. That depends only on the expected lift in the next thermal and the polar.

For a final glide to a fixed point on the ground -- airport, turnpoint (where you are going to significantly change direction), mountain peak or ridge -- then yes you should change your speed roughly as you indicate.

3: Does anyone on this forum actually ever do the research before replying? Just curious. The B/S ratio applies to more than thermals...

Some of us do, yes.