Yes, I realized after I wrote the post that calculating LD can't be done without speed, distance and altitude lost. You can figure out feet per minute sink, but then there is the airmass wild card.

The original test with the Cirrus was flown in a straight line at the following IAS. 70, 60, 50, 40. Then I turned the opposite direction and flew the same speed sets. Might be better to fly one speed, do an immediate 180 and fly the same speed. Probably for longer that the 45 seconds per speed that I used.

Also realize that TAS has to be computed, ASI calibrated, winds and airmass.. ... Aaron