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FES system highlights

FES is Fun, Easy and Safe!

  • Ultimate self-sustainer system for high performance sailplanes, like Discus, Ventus, LAK17 etc.
  • Offers total independance as self-launching system on light sailplanes, like Silent 2, MiniLAK.
  • During powered flight there is no additional drag, so less power is required for the same performance.
  • Only a few moving parts and therefore more reliable system, compared to the retractable solutions.
  • There is no shift in the centre of gravity due to the operation of the engine.
  • Plenty of 12V power supply during long flights for all instrumentation (flight computer, radio, transponder, leg heaters, PDA...)
  • A baggage compartment still available as at pure sailplane.
  • The propeller is not running close to pilot head.
  • No smell of gasoline or diesel fuel in cockpit.

Front Electric Sustainer with foldable propeller, can be started at much lower altitude, compared to minimum safe altitude which is recommended for safe starting procedure of typical retractable system with combustion engine. With FES its maximum power can be available in 1-2 seconds, after decision to start motor. Such unbeatable short starting time is huge advantage in critical moments, when otherwise typical 30-45 seconds long starting procedures with extended propeller fells like eternity, due to increased drag and increased sink rate. At FES there is no additional drag of propeller and motor, so even in case of motor failure landing would be like with pure sailplane. Starting motor in downwind at 150m, instead of at otherwise recommended 450m, gives you quite an edge on weak days. It is not rare to find a thermal which saves you well below 450m and it is so good to find them! With only 45-50kg of additional weight, you can still climbing easily in a weak thermals with typical 18m sailplane.

When FES is started above potential outlanding field, it is usually just necessery to climb to safe altitude, then power is reduced for level flight to the nearest thermal or to your home airfield. Endurance in horizontal flight with low power setting (4kW) is about one hour, giving you a range of about 75-100km.

Climb rate at max power (22kW, 4500-4700RPM) is around 1.5-3m/s, depending on glider type, its weight, and voltage level and temperatures. With fully charged battery packs is possible to climb 1200-1600m. Max altitude gain can be achieved with approximately 14kW of power (4000RPM).

When using aerotowing is safe to release in the first weak thermal and cut down an expensive towing bill. If thermal strength is not sufficient, you can easely start FES for a few minutes to stay airborne. Otherwise you would need to land and wait in a starting grid for another tow. With FES you can always start your long cross-country flights earlier.

Imagine take-off from a short runway, fully ballasted and towplane with engine problem on low altitude. In such critical situation you can release the towing rope, and start FES immediately to climb away from risky situation, saving you and your precious sailplane.

In combination with winch launching or even car towing, FES will greatly expand your horizons.