Originally powered by a converted NSU Ro 80 Wankel-type automotive engine, Berger later fitted a BMW 6012 turbine to the aircraft, and later still another adapted automotive Wankel engine, this time from a Mazda RX-7.
Designed by Claus Luthe, the K70 was originally developed by NSU as a smaller brother to the Ro 80, distinguished by its conventional piston engine rather than the Ro80's Wankel rotary engine.