A thought regarding usage of IAS, TAS and GS for wind calculations: I have been a long term abuser of this, when flying with the Zander GP940 who only calculate the wind during circling. The wind component calculation is of great information on final glide to detect any changes of wind when getting closer to the ground. But I just got a second thought about this.

When reading this tread and putting 1+1 together do I realize that using the difference between TAS and GS is not an useful approach to calculate the wind. Read any of the Johnsson reports and figure out why he is so keen on calibrating the IAS readings!
It is not uncommon that the IAS differs from TAS(at ground level) with more than 5%, it is individual both between types of gliders and most likely also within gliders of the same type depending on which static probe you are using.
This error in reading the IAS in the glide computer is not calibrated, therefore can it not use the difference TAS / GS to calculate the wind. The error would be of dignity 5-15 km/h.