Sikorsky R-6

The Sikorsky R-6 was an American light two-seat helicopter of the 1940s, called the Hoverfly II in Royal Air Force and Royal Navy service. Developed to improve on the successful R-4, it had a completely new streamlined fuselage and a longer, straightened tail boom while keeping the R-4 main rotor and transmission, and Sikorsky gave it the Model 49 designation. It could reach 100 mph against 82 mph for the R-4. Sikorsky built the first aircraft but most were built by Nash-Kelvinator, and the first R-6s were delivered to the US Army Air Forces in late 1944.