The Bell H-13 Sioux is a single-engine single-rotor light helicopter built by Bell Helicopter. Westland Aircraft manufactured the Sioux under license for the British military as the Sioux AH.1 and HT.2.
First flight: 8 December 1945 (Bell 47 prototype)
Primary users: United States Army, United States Air Force, United States Navy, British Army
Number built: 2,407
OH-13H version – based on 47G-2. Equipped with a 250 hp (186 kW) Lycoming VO-435 engine. At least 453 acquired by US Army.