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-34 Sikorsky S-34 The Sikorsky S-34 was a 1920s American six-seat sesquiplane, designed and built by the Sikorsky Manufacturing Corporation. Only one was built but the design led to the successful Sikorsky S-38. The S-34 was a sesquiplane amphibian with a boat hull, being powered by two tractor Wright Whirlwind J-4 engines. It had a boom-mounted twin-rudder tail unit and room inside the hull for five passengers. During a test flight in November 1927 one engine failed and the S-34 crashed and sank. Igor Sikorksy and the others onboard escaped without injury but the S-34 was destroyed. It was the first