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-6 Sikorsky S-6 The Sikorsky S-6 was a Russian single engine experimental aircraft similar to the S-5, built in 1911 by Igor Sikorsky. Construction of the first S-6 was started in August 1911. The three bay biplane was powered by an Argus 4-cylinder water-cooled engine producing . Initial flight tests in late November were disappointing, revealing a long take-off run and poor climb performance. Sikorsky disassembled the aircraft and took it home where substantial modifications were undertaken, including lengthening the wingspan and reducing aerodynamic drag by enclosing the fuselage with wood veneer. Ailerons on the lower wing were removed and strut