FES system highlights

With FES you can go to places you would never dare before!

  • Reduced aerodynamic drag, so much less power is needed for the same performance
  • Simplified with only a few moving parts and therefore a lighter system when compared with the retractable solution.
  • The aerodynamics of the sailplane are not changed during engine operation.
  • There is no shift in the centre of gravity due to the operation of the engine.
  • The propeller is not running close to pilots head.
  • A baggage compartment still available as at pure sailplane
  • Finally enough energy for Flight computer, radio, transponder, leg heaters, PDA...

An electric motor with a foldable propeller, can be safely started at a very low altitude. In case of system failure you can land like all other pure sailplanes, without the additional drag of a propeller and motor. Starting the motor on a downwind leg at 150 m, instead of the usual 450 m, gives you quite an edge on weak days. It is not rare to find a thermal which saves you well below 450 m and it is so good to find them! With only 45kg of additional weight, you can still easily climb away in a weak thermal.

Without finding a thermal, switching ON the motor results in a maximum climb rate of 2-3 m/s (depending on glider type and its weight). After reaching a safe altitude, power is usually reduced for horizontal flight to the nearest thermal or to your home airfield. Endurance in horizontal flight under low power (4kW) is about one hour, giving you a range of about 90 km or to climb 1200-2000m (depending on type of sailplane and its weight) and glide home.

If you start with an aerotow you can release very low in the first thermal and cut down an expensive towing bill. If the thermal is not sufficient you can start the motor for a few minutes. You can avoid dumping water ballast or even too early landing and than waiting in a row for another tow. With FES you can enjoy to start your memorable cross-country flights much earlier and with more water ballast.

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

Using winch starts or car tows, FES could greatly expand your horizons.