http://www.trimill.com/cusoft/PolarExplorer/Generalized_STF_Theory.pdf

The DOS implementation of the theory
here.

Find out the optimum circling technique for any glider at any
altitude and wing loading.

Calculate climb performance in thermals of different strength and shape.

Plan and analyze cross-country flights and final glides.

Compare circling and cross-country performances in addition to comparing polars.

Calculate more realistic handicap factors based on the cross-country performance
for the expected or actual weather conditions.