Sikorsky Aircraft and it became a part of [[United Aircraft and Transport Corporation]] (now [[United Technologies Corporation]]) in July of that year. [[File:Sikorsky Aircraft Corporation ad Model S-42 Clipper Flying Boat 1937.jpg|thumb|left|upright|Advertisement for [[Sikorsky S-42]] Clipper flying boat from 1937]] In the United States, Igor Sikorsky originally concentrated on the development of multi-engined landplanes and then amphibious aircraft. In the late 1930s, sales declined and United Aircraft merged his division with [[Vought Aircraft]]. He then began work on developing a practical helicopter. After first flying the [[VS-300]] he developed the [[Sikorsky R-4]], the first stable, single-rotor, fully controllable [[helicopter]] to enter full-scale
Sikorsky S-5 during a country fair at Belaya Tzerkov, near Kiev. Between nine and ten flying hours were logged before the S-5 was lost in late fall. The crash was caused by fuel starvation due to debris (a mosquito) blocking the carburetor jet. Sikorsky S-5 The Sikorsky S-5 was an early Russian single seat biplane design by Igor Sikorsky, completed in late April 1911. The S-5 was powered by a Argus water-cooled engine turning a propeller Sikorsky designed and built himself. The fabric covering the wooden wings was tightened with pure alcohol and glue mixed with boiling water while the fuselage structure