08/31/2007. The static Heli-Trainer embodied all essential elements of a conventional helicopter, but was mounted on an articulated gantry to allow a student controlled experience of helicopter systems. The gantry allowed the helicopter to rise to a height of 2 ft (0.6 m), turn around a vertical axis and dip at up to 6° but prevented it from flying outside these limits. A 40 hp Hirth engine drove an one-bladed glass fiber rotor with a counterweight. Eighteen Heli-Trainers were sold to the German forces.