May 262012
NACA and the Convertible Aircraft, 1945-9

The convertible aircraft, a vehicle which can function either as a direct lift, rotary aircraft or as fixed wing airplane, with conversion from one to the other type as required, has long been a dream of aeronautical inventors. Combining the vertical flight capacity of the helicopter with the greater efficiency in forward flight of the […]

Apr 062012
Doblhoff Wnf 342 V4 Helicopter—Evaluation by General Electric (1948)

The photos above depict the Doblhoff Wnf 342 V4, an experimental German helicopter which employed tip jets to drive the rotor. It was built by a group of Austrian engineers at the Wiener Neustädter Flugzeugwerke headed by Friedrich von Doblhoff and was originally designed to fulfill a German Navy requirement for an observation platform to be […]

Oct 192011
Bendix Model J Four Place Helicopter (1946)

In September 1946, Bendix Helicopter sent an unsolicited proposal to the US Navy Bureau of Aeronautics for its Model J four place helicopter. The company was organized in 1943 as Helicopters, Inc., and in 1944 this was changed to Bendix Helicopter, Inc. The parent company was Bendix Corporation, founded by prolific inventor and industrialist Vincent H. […]

Oct 042011
Stiller Helicopter Project of 1928

On January 1, 1928, brothers I. and J. Stiller, both of whom were engineers living in Radom, Poland, filed a patent in Warsaw for a peculiar helicopter design featuring two small propellers fitted on the upper end of swiveling shafts arranged in parallel. These propellers were driven by an internal combustion engine located between the shafts. […]