Sikorsky R-4 end of the boom near the tail rotor while others had it positioned at the midpoint of the boom. Additionally, some had short "stub" exhaust pipes from the engine while others had a much longer one which extended vertically and then aft above the main landing gear struts. Sikorsky R-4 The Sikorsky R-4 is a two-seat helicopter designed by Igor Sikorsky with a single, three-bladed main rotor and powered by a radial engine. The R-4 was the world's first large-scale mass-produced helicopter and the first helicopter used by the United States Army Air Forces, the United States Navy, the United
Igor Sikorsky Kyiv Polytechnic Institute Igor Sikorsky Kyiv Polytechnic Institute The National Technical University of Ukraine "Igor Sikorsky Kyiv Polytechnic Institute" (NTUU "KPI") is a major university in Kiev, Ukraine. In January 2012 Webometrics Ranking KPI made it into top 1,000 – taking 957th place out of 20,300 universities, 510th (February 2013). The institute was founded on 31 August 1898 as the Kiev Polytechnic Institute of Emperor Alexander II, but its current building complex was not built until 1902. Until then, the institute was renting out its space at the building of Commercial School located on Vorovsky Street. At that time it had four departments: