Klaus Burhard publishes a wonderful news and blog site promoting ultralight sailplanes. His German site has been the source for many blog entries by yours truly, and the latest items from Klaus are of concern to anyone involved with electric aircraft. He has reported in the last week on a disturbing incident with a UK-based HPH glass-wing 304eS/Shark FES “self-starter,” or self-launching sailplane. The airplane is a standard-class 15 meter (49.2 feet) wingspan plane. As seen in the video below, The FES (Front Electric Sustainer) motor on the nose swings a propeller which folds into the front contours of the sailplane when not powering the plane. When a pilot engages power, the rotation of the motor pushes the propeller blades out into the airstream. Two battery packs engineered by FES nest in a compact area behind the pilot. Each pack contains 28 high-power Kokam lithium-polymer batteries of 43 Amp-hours each wired in series to give 2.1 kilowatt-hours of energy. Packs …
