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 VS-44 Sikorsky VS-44 The Sikorsky VS-44 was a large four-engined flying boat built in the United States in the early 1940s by Sikorsky Aircraft. The VS-44 was designed primarily for the transatlantic passenger market, with a capacity of 40+ passengers. Three units were produced: "Excalibur", "Excambian", and "Exeter". In the early 1930s, the primary mode of long-distance air travel over oceans was in flying boats, due to the ease of constructing docking facilities on shore without having to construct runways, and the possibility of malfunction forcing a sea landing. One flying boat designer was Russian immigrant Igor Sikorsky who had founded