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.

Paul Baumgärtl, born in 1920 and died on June 22, 2012, was an Austrian engineer who contributed to the development of rotary wings. Less known than his compatriot Bruno Nagler, benefiting from the encouragement of the Reichsluftfahrtministerium (RLM, in French Reich Air Ministry) but from no official support, he worked during the Second World War on the production of ultra-light machines in front of allow the rapid movement of infantry or the crossing of obstacles. When the war was over, he emigrated to Brazil to continue his work there, making three other devices. None of Paul Baumgärtl's achievements reached the series production stage