Bell H-13 Sioux

The Bell H-13 Sioux is the American military version of the Bell 47 single-engine light helicopter, built by Bell for the United States Army and produced under licence by Westland in Britain as the Sioux AH.1 and HT.2. The Army first ordered Bell 47s in 1948 under the H-13 designation, and the type became one of its principal helicopters in the Korean War, where the H-13D was the most common variant and its medical evacuation work earned the nickname Angel of Mercy. It was also used as an observation helicopter early in the Vietnam War until the Hughes OH-6 Cayuse replaced it in 1966. The 47G version used a 260 horsepower Lycoming VO-435 piston engine and a two-bladed rotor stabilised by a gyro bar, with skid landing gear and a bubble canopy.