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-35 Sikorsky S-35 The Sikorsky S-35 was an American twin-engined sesquiplane transport later modified to use three-engines. It was designed and built by the Sikorsky Manufacturing Company for an attempt by Rene Fonck on a non-stop Atlantic crossing for the Orteig Prize. It was destroyed in the attempt. The S-35 was designed as a twin-engined transport with a range. During 1926 Rene Fonck, a French First World War fighter ace, was looking for a multi-engine aircraft to enter a competition to be the first to fly non-stop from New York to Paris. The prize was $25,000, offered by Raymond Orteig. Fonck