Based on some previous postings on the FES and the questions regarding the drag effects of the FES propeller blades, attached for everyone's info is a URL to the final Idaflieg FES testing report dated Feb 21,2014.
http://www.front-electric-sustainer....A%20FES_en.pdf
Keep in mind that this evaluation was done on a LAK-17a FES. For new LAK gliders FES installations at the LAK factory are being done on the LAK-17b and more recently, an FES installation was done on a LAK-19.
As many of you are also aware, the FES is available on the Alisport Silent 2 Electro.
Thx - Renny