The First Single Rotor Helicopter
In 1939 a helicopter, designed by Russian-American Igor Sikorsky, performed the first successful flight and became the first functional single rotor helicopter. The VS-300 had a single rotor with three blades powered by 75 horsepower engine. The helicopter was also the first helicopter to successfully use a vertical tail rotor. The VS-300 was eventually developed into the Sikorsky R-4 which was the first mass produced helicopter for the United states Air Force.