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,
Igor Sikorsky Kiev Polytechnic Institute. After the academic year, Sikorsky again accompanied his father to Germany in the summer of 1908, where he learned of the accomplishments of the Wright brothers' Flyer and Ferdinand von Zeppelin's dirigible. Sikorsky later said about this event: "Within twenty-four hours, I decided to change my life's work. I would study aviation." By the start of World War I in 1914, Sikorsky's airplane research and production business in Kiev was flourishing, and his factory made bombers during the war. After the Bolshevik revolution began in 1917, Igor Sikorsky fled his homeland, because the new government threatened to