"David Starer" wrote in message ...
For calculating a final glide, you only need to know the wind component
along the final track; it isn't actually necessary to know the absolute wind
strength and direction. The difference between true airspeed (corrected IAS)
and ground speed (from the GPS) is equal to the component you need, so the
glider's heading isn't required.

David Starer


This is only true if you can wait for the solution until you are
established on the final glide from the last turnpoint. Most of us
want the solution before rounding the last point, or perhaps even
before the last several turnpoints if working close in points to use
up a good last thermal on a MAT or PST. The wind direction and
magnitude are both required to derive that solution.


Andy