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 XP2S Sikorsky XP2S The Sikorsky XP2S was an American biplane patrol flying boat developed for the United States Navy during the early 1930s. After selling a small quantity of PS / RS patrol / transport amphibians to the Navy, Sikorsky (then a division of United Aircraft Corporation) endeavoured to interest the service in a patrol flying boat. Having received a development contract in mid-1930, Sikorsky delivered a complete aircraft for testing in June 1932. The XP2S-1, as the prototype was designated, was a two-bay, equal-span biplane of mixed construction. Its two R-1340 Wasp radial engines were mounted in a single nacelle