Highlights

                Reduced aerodynamic drag, so less power is needed.
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 your head.
A baggage compartment still available.
Finally enough power for all your instruments, PDA, 
					radio, transponder... 

                

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 less than 35 kg of additional weight, you can easily climb away in a weak thermal.

Without finding a thermal, switching on the engine would result in a maximum climb rate of 1,6m/s. After reaching a safe altitude, power can be reduced for horizontal flight to the nearest thermal or to your home airfield. Endurance in horizontal flight under low power is more than one hour, allowing you to fly more than 90 km or to climb at maximum power to about 1500m 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 avoid dumping water ballast and avoid landing and waiting for another tow. You could easily start much earlier for a long cross-country flight with full water ballast.

Imagine a short runway and a towplane with engine problems. In such a critical situation you could release the tow rope, start FES immediately and climb away to save you and your glider.

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