Austrian engineer Paul Baumgärtl was working on the design of a rucksack helicopter, officially supported, but without RLM commission (Reichsluftfahrtministerium, Reich Air Ministry). Heliofly I, his first device, was developed in 1941, but did not satisfy. After that “Heliofly III/57″ was built, designed for military purposes. It had two single-bladed counterrotating rotors driven by an 8-shp Argus engine that proved to be too weak. So Heliofly III/59 was developed with a 16-shp engine. Its weight was only 35 kg, and it had a take-off weight of about 120 kg. A number of flights were conducted by Baumgärtl until the fighter emergency programme forced the suspension of the development.