Baumgartl Heliofly I
The Austrian engineer, Paul Baumgartl, concerned himself during the Second World War with the design of small single-seat helicopters, in the suburbs of Vienna. Baumgartl's first product was the Heliofly I of 1941, which was little more than a strap-on autogyro glider for sporting use.
The Heliofly III-57 resulted from previous work. This had a rotor consisting of two co-axial contea-rotating single blades, each of which was to be driven by its own 8 hp Argus As 8 engine, which also acted as a counter-balance.
Baumgartl Heliofly III-59
When it became apparent that the Argus engines could not be readily obtained, the helicopter was redesigned in 1943 as the Heliofly III-59 to be powered by a single 16 hp engine. In this design, the engine drove and counterbalanced the lower blade and, through gearing, also drove the upper blade, so that torque was still counterbalanced by contra-rotation. A weight, instead of an engine, counterbalanced the upper blade, and the flapping rotor system had cyclic pitch control.
Engine: 16 hp / 12kW
Rotor diameter: 6.10m
Max take-off weight: 120kg
Empty weight: 35kg