A Dream Nearing Realization

Certain objects stir deep feelings upon first viewing.  DESiE is one such object.

Desie (in simulation) by the Matterhorn

Its name alphabetizes its description, as translated and explained by one of its creators, Wolfgang Liehmann. 

 D = doppelsitziges = double-seated

E = Enten = duck/canard = tail first

S = Segelflugzeug = sailplane

i = mit integriertem = with integrated

E = Elektroantrieb = electrically-powered engine

This two-seater, electrically-powered, canard sailplane has been a labor of love, taking 13 years to reach its current stage, and projected to take another three before its first real flight.  In the meantime, diligent toil and breaks for X-Plane simulated flying are leading toward an aircraft that Wolfgang says, “Shows very satisfying behavior with respect to stall and glide properties.”

 Starting in 1993, the DESiE team found that motors of that time were not as powerful as they are now.  Wolfgang’s approach to solving that problem is indicative of the cleverness of the overall design.  He used six brushless DC inrunner industrial servo motors (normally used in robotic applications), running through toothed belts through a gear reduction to push 20 kW through a single, highly efficient, large, two-bladed propeller.  He modified a Kontronik controller to allow its use at 85 Volts to manage the motors.  Wolfgang notes that today, one could buy a large outrunner, such as the Geiger/Eck HPD10 to avoid doing it yourself.

Desie's six motors and belt reduction system

Desie's folding propeller, showing fine workmanship

DESiE is a high-tech object of desire, with flexible retractable gear, folding propeller, and an “innovative glass instrument panel with [a] display of flight controls, horizon, [and] system controls.”  It has independent battery and photovoltaic power supplies.  Micro controller supervision of batteries and motors lessens the workload of the pilot, as does the servo-enhanced air resistance rudder which helps control yaw.  In fact, the team claims that the airplane can be flown “without using your legs.”

Desie's Glass Cockpit

With a main wingspan of 20.6 meters and an aspect ratio of 25:1, one would expect a high glide ratio.  44:1 at 87 kilometers per hour at a wing loading of 34.5 kg per square meter does not disappoint.  Because of its carefully calculated design (“with the most modern algorithms”), the airplane has an empty weight of only 345 kg (759 pounds), and even with 66 kg (145.2 pounds)thrown in for “energy storage” manages to top out at only 610 kg (1,342 pounds) – within LSA parameters.  That, and the overall cleanness of the design, probably contribute to its climb rate of 1.6 meters per second (307 feet per minute).  This is not bad for a two-seater with a mere 27 horsepower.

"With the most modern algorithms"

 Although paying sponsors have not been found in abundance, DESiE’s team of 15 stalwart souls at Silent Flight e. V. presses ahead, earning a Berblinger Award from the City of Ulm in southern Germany, and a well-earned respect for their tenacity.  We can only hope for the successful completion of their project, since we share an understanding of their goals, as stated in the team’s 2009 Aero Expo brochure.

“Didn’t you always intend to ride a glider with a friend and enjoy the sun, the wind and the clouds, do the launch independent without the noise and air pollution, come home safely even in dubious weather conditions?  We do – that’s why we build: DESiE.”

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