|Baumgartl Heliofly III-57
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. It is not certain whether his work was sponsored by the German Government, but his machines were in the same category as those of Nagler-Rolz. Baumgartl's first product was the Heliofly I of 1941, which was little more than a strap-on autogyro glider for sporting use.
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.
J.R.Smith, Antony L. Kay "German Aircraft of the Second World War", 1972