An Austrian inventor Paul Baumgärtl worked on
a development of a backpack helicopter before the WWII
and his first project "Heliofly I" was finished in 1941.
RLM encouraged him (though the official contract was
never signed) to produce a special military version of
his helicopter - the "Heliofly III/57". It was a two opposed
single blade rotors backpack helicopter powered with an Argus
As.8 engine. The further development was called "Helio-
fly III/59"; it was powered with even more powerful 16hp
engine, its dry weight was only 35kg and the takeoff weight
was about 120kg. Baumgärtl had made several flights, but
the desperate military situation by the end of the war put
an end to his extraordinary project.