Two Battery Fires in Self-Launching Sailplanes

Dean Sigler Batteries, Sustainable Aviation Leave a Comment

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 …

FES Installs Sustainer on German Sailplane

Dean Sigler Electric Powerplants, Sustainable Aviation 1 Comment

Luka Žnidaršič  of FES (Front Electric Sustainer) directed your editor to the following.  His company displayed at Aero 2014 in Friedrichshafen, Germany during that stellar event, showing off the latest sailplane to use their integrated power system. “We are glad to inform you that during Aero 2014 we presented our new Ventus 2cxa FES. We performed installation in cooperation with Schempp-Hirth manufacturer. This is first FES system installed on German type of sailplane.   Luka adds, “We made this development in cooperation with Schempp-Hirth who also recognized potential of the FES system.  The new Ventus 2cxa FES is available for about 100.000€+VAT taxes and options.” “Pictures show more than words!” Both Luka and his father Matija started as model aircraft builders and transferred that love of aircraft to real sailplanes; Luka has over 2,200 hours in more than 30 sailplane types, and Matija has about 3,000 gliding hours.  They used their considerable talents and degrees to help design their own motors, controllers, …

Sustainable Soaring

Dean Sigler Electric Powerplants, Sustainable Aviation Leave a Comment

Glaser-Dirks Flugzeugbau, the German sailplane manufacturer, has introduced the DG-1001te, a two-seat, electric turbo craft that can sustain flight and even show a modest rate of climb, but is not capable of self-launching. The “turbo” designation is common on European craft that rely on a pop-up motor to maintain flight in unfavorable soaring conditions.  Following an aero-tow or winch launch, the sustainer engine is used to allow “get-home mode” operation, or to maintain altitude while the pilot searches for areas of better lift. Until recently, single- and two-cylinder Solo two-stroke engines served on many applications.  Electric motors are beginning to find favor, though, because of their ease of starting and the fact that their light weight and high power output counterbalance the added weight of batteries.  The battery pack can be kept small because of the small power output required to keep sailplanes airborne – under five horsepower at best gliding speed for even large birds. Luka and Matija Znidarsic, …

FES at Friedrichshafen

Dean Sigler Electric Powerplants, Sustainable Aviation 1 Comment

The Front Electric Sustainer motor system, developed by Slovenian father and son entrepreneur team Matija and Luka Znidarsic, was on display at the E-Flight Expo, part of the larger Friedrichshafen Aero 2010 show.  Both are graduates in Mechanical Engineering from the University of Ljubljana.   This system, described in an earlier entry (“Power Up Front,” November 1, 2009), is meant to provide power for a sailplane that is launched by other means, such as an aerotow or winch.  Its light weight does not detract from the normal performance of the sailplane, but does enhance safety, with the pilot able to start the motor and power away into a modest climb if necessary to save a flight. In response to this editor’s naive questions, Luka responded, “No, there is no problem with scraping the fuselage!  Stopping is very soft, and at run blades open immediately.“ He notes that the propeller is visibly improved, “As attachment bolts are now inside of spinner, and so not visible, and aerodynamically more …