"FES": an electric nose drive to start on your model from the ground.
So no starting rubber or starting cart is needed and the small propeller is clean on the fuselage. Internationally, the name "FES" (Front Electric Selflaunch / Sustainer) has prevailed for this type of drive. Of course Hacker Motor GmbH also offers some drive combinations. Usually tall gliders from 4 - 5m wingspan and larger are equipped with these drives . The engines of the A60-L Glider series are already flying large glider models with up to 45kg.