|Baumgartl Heliofly III-59|
Resulting from previous work was a design in 1942 for a strap-on helicopter. This was the Heliofly III-57, which 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. 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.
J.R.Smith, Antony L. Kay "German Aircraft of the Second World War", 1972
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Technical data for Heliofly III-59
Crew: 1, power capacity: 12kW, rotor diameter: 6.10m, take-off weight: 120kg, empty weight: 35kg