Igor Sikorsky On June 27, 1931, Sikorsky filed for a patent for another "direct lift aircraft", and was awarded patent No. 1,994,488 on March 19, 1935. His design plans eventually culminated in the first (tethered) flight of the Vought-Sikorsky VS-300 on September 14, 1939, with the first free flight occurring eight months later on May 24, 1940. Sikorsky's success with the VS-300 led to the R-4, which became the world's first mass-produced helicopter, in 1942. Sikorsky's final VS-300 rotor configuration, comprising a single main rotor and a single antitorque tail rotor, has proven to be one of the most popular helicopter configurations,
Sikorsky S-12 Sikorsky S-12 The Sikorsky S-12 was a Russian single engine trainer aircraft completed in the spring of 1913 by the Russian Baltic Railroad Car Works while Igor Sikorsky was the chief engineer of the aircraft manufacturing division. The S-12 was a single seat mid-wing monoplane with wire-braced wings and powered by a Gnome Lambda air-cooled rotary engine rated at . It was smaller and lighter than the S-11 on which it was based, and was specifically designed to be highly maneuverable. The S-12 was the most successful monoplane Sikorsky designed during his time in Russia and twelve examples were produced.