Sikorsky S-75 Sikorsky S-75 The Sikorsky S-75 was a proof-of-concept all-composite helicopter. Sikorsky Aircraft used all-composite materials to replace metal to provide greater strength, lighter weight, lower manufacturing costs, and reduce maintenance costs. The Sikorsky S-75 was developed under the US Army's Advanced Composite Airframe Program (ACAP), the goal of which was the development of an all-composite helicopter fuselage, lighter and less costly to build than predominantly metal airframes in support of the Light Helicopter Experimental (LHX) program. In February 1981, contracts were awarded to Sikorsky and Bell Helicopter, with Bell submitting its Model D292. The S-75 flew for the first time
Igor Sikorsky first flight on May 13, 1913. In recognition for his accomplishment, he was awarded an honorary degree in engineering from Saint Petersburg Polytechnical Institute in 1914. Sikorsky took the experience from building the Russky Vityaz to develop the S-22 "Ilya Muromets" airliner. Due to outbreak of World War I, he redesigned it as the world's first four-engined bomber, for which he was decorated with the Order of St. Vladimir. After World War I, Igor Sikorsky briefly became an engineer for the French forces in Russia, during the Russian Civil War. Seeing little opportunity for himself as an aircraft designer in