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 Ilya Muromets Air Shooting and Bomb-dropping School in Serpukhov. One Ilya Muromets S-22 replica exists in the Monino Air Force Museum near Moscow. Sikorsky Ilya Muromets The Sikorsky "Ilya Muromets" () (Sikorsky S-22, S-23, S-24, S-25, S-26 and S-27) were a class of Russian pre-World War I large four-engine commercial airliners and military heavy bombers used during World War I by the Russian Empire. The aircraft series was named after Ilya Muromets, a hero from Slavic mythology. The series was based on the Russky Vityaz or Le Grand, the world's first four-engined aircraft, designed by Igor Sikorsky. The Ilya Muromets aircraft as