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
Sikorsky S-7 The S-7 was entered in the international military competition at Saint Petersburg in August 1912. During a take-off attempt from a furrowed field the landing gear was severely damaged and the S-7 was unable to finish the completion. In 1913 the aircraft was repaired and served as a trainer. In 1914 Bulgaria purchased the S-7 and used it in operations during World War I. Sikorsky S-7 The Sikorsky S-7 was a Russian single engine experimental prototype aircraft built by the Russian Baltic Railroad Car Works shortly after Igor Sikorsky became chief engineer of the aircraft manufacturing division. The S-7 was