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-16 delivered in early 1916. Although highly maneuverable, the S-XVI possessed a comparatively poor performance due to insufficient power. A further small batch were completed in 1917, with the aircraft being used during the Russian Revolution and staying in service until 1923. At least one aircraft have been used by the Ukrainian People's Republic after 1917. Sikorsky S-16 The Sikorsky S-16, or RBVZ S-XVI (named after its manufacturer), was a Russian equi-span single-bay two-seat biplane designed by Igor Sikorsky in 1914-15. Conceived in response to demand for an escort fighter for the Ilya Muromets bombers, it was noteworthy in that it