Sikorsky X2 Sikorsky X2 The Sikorsky X2 is an experimental high-speed compound helicopter with coaxial rotors developed by Sikorsky Aircraft. Sikorsky developed the X2 helicopter on a $50 million budget. The design includes expertise gathered from several earlier design projects. The S-69/XH-59A Advancing Blade Concept Demonstrator had shown that high speed was possible with a coaxial helicopter with auxiliary propulsion (two jet engines), but that vibration and fuel consumption was excessive; the Cypher UAV expanded the company's knowledge of the unique aspects of coaxial flight control laws with a fly-by-wire aircraft; and the RAH-66 Comanche developed expertise in composite rotors and advanced
Sikorsky S-18 leave the ground. Sikorsky S-18 The Sikorsky S-18 was a Russian twin engine aircraft designed by Igor Sikorsky and built by the Russian Baltic Railroad Car Works aviation division at Petrograd during World War I. The S-18 was a large three bay biplane fighter/interceptor powered by two Sunbeam Crusader V-8 water-cooled engines mounted on the lower wing in a pusher configuration. The aircraft featured armor protection for both crew members with the gunner/observer seated in the nose and armed with a single machine gun. The aircraft was very heavy and with the less than reliable Sunbeam engines neither example built