FES Discus 2c - Glide and Powered Flight Performance

FES Flight Manual, v1.18 May 2020
Page 27 of 35
5.3 Non-approved further information
5.3.1 Demonstrated crosswind performance
FES equipped sailplane has the same crosswind performance as the pure glider version of
the aircraft.
5.3.2 Glide performance
Idaflieg flight comparison measurements of the LAK17A FES (August 2012) showed
only a minor effect of the propeller blades on glide performance. It is reduced by around 1
L/D point over the entire speed range.
As you can see from the graph above, even the cockpit ventilation has some effect on the
flight polar (reduction of around 0,5 L/D point).