Sikorsky R-4 Sikorsky R-4 The Sikorsky R-4 is a two-seat helicopter designed by Igor Sikorsky with a single, three-bladed main rotor and powered by a radial engine. The R-4 was the world's first large-scale mass-produced helicopter and the first helicopter used by the United States Army Air Forces, the United States Navy, the United States Coast Guard and the United Kingdom's Royal Air Force and Royal Navy. In U.S. Navy and U.S. Coast Guard service, the helicopter was known as the Sikorsky HNS-1. In British service, it was known as the Hoverfly. The VS-316 was developed from the famous experimental VS-300 helicopter,
Sikorsky S-5 Sikorsky S-5 The Sikorsky S-5 was an early Russian single seat biplane design by Igor Sikorsky, completed in late April 1911. The S-5 was powered by a Argus water-cooled engine turning a propeller Sikorsky designed and built himself. The fabric covering the wooden wings was tightened with pure alcohol and glue mixed with boiling water while the fuselage structure was left exposed. Instead of separate levers to control the elevator and ailerons as in his previous aircraft, Sikorsky designed a single control lever with a wheel allowing control of pitch and roll. This "control column" included a button switch to