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
Igor Sikorsky war-torn Europe, and particularly Russia, ravaged by the October Revolution and Civil War, he immigrated to the United States, arriving in New York on March 30, 1919. In the U.S., Sikorsky first worked as a school teacher and a lecturer, while looking for an opportunity to work in the aviation industry. In 1932, he joined the faculty of the University of Rhode Island to form an aeronautical engineering program and remained with the university until 1948. He also lectured at the University of Bridgeport. In 1923, Sikorsky formed the Sikorsky Manufacturing Company in Roosevelt, New York. He was helped by