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 SH-3 Sea King to pursue the further development of the Sea King for other markets beyond the US Navy. One of the major variants of the Sea King to be produced was a model for civil operators, which was designated as the Sikorsky S-61L. The first operator of the S-61L was Los Angeles Airways, who introduced the type to service on 11 March 1962. Another noteworthy Sea King variant, the significant change this time being the adoption of a conventional hull, the Sikorsky S-61R, was also concurrently developed for transport and search and rescue (SAR) duties, this type being extensively operated by the