Apart from its "Turbo" retrieve system (by Prof. Oehler), which is installed in the fuselage deck, there is no difference from the unpowered sailplane model NIMBUS-4DL. Likewise, it has hardly any disadvantages in performance and flight handling.
The utilization spectrum of the NIMBUS-4DLT, however, is much wider: Not only has the risk of an off-field landing been considerably reduced, but "soaring safaris" (range in "saw-tooth" mode than 240 nm), or for instance, exploratory wave flights, may also be conduced with the aid of this propulsion system. The advantages of this result mainly from its uncomplicated structure, its simple control and maintenance, its associated operational reliability and in particular, its light weight. The system has been proven in hundreds of Schempp-Hirth sailplanes operated all over the world.
The operation of the "Turbo" retrieve system does not require any particular skill as there is no starter, throttle or choke. The air cooled two-cylinder power plant (model SOLO 2350, 19.6 kW) is extended and reacted by means of an electrical spindle drive. This is operated by an ILEC multi-function control box, especially developed for the "Turbo" system. Its LED signals provide information on RPM, battery voltage, engine positions etc. Fuel contents are read off directly from the tank which is removable for filling at a gas station. A fixed fuel tank is available as an option.
The engine is started by the windmilling effect of the multi-blade folding propeller (at a speed of about 120 km/h | 75 mph) and is present to operate at full power. It is stopped by switching the ignition to "off" and reducing the speed to about 75 km/h (50 kt | 47 mph). Once the propeller has stopped spinning, the engine is put away regardless of the position of the blades.
For sanctioned contests the NIMBUS-4DLT can be quickly restored to a pure sailplane by removing the engine, its battery, propeller and fuel tank. This results in a weight reduction of nearly 30 kg (66 lb).