The first member of the prolific Huey family, it was developed by Bell Helicopter to meet a 1952 US Army requirement for a medical evacuation and utility helicopter, and first flew in 1956. The UH-1 was the first turbine-powered helicopter produced for the United States military, and more than 16,000 have been built since 1960. The Iroquois was originally designated HU-1, hence the Huey nickname, which has remained in common use, despite the official redesignation to UH-1 in 1962. The UH-1 first saw service in combat operations during the Vietnam War, with around 7,000 helicopters deployed. The Bell 204 and 205 are Iroquois versions developed for the civil market. The UH-1 has a metal fuselage of semi-monocoque construction with tubular landing skids and two rotor blades on the main rotor. Early UH-1 models featured a single Lycoming T53 turboshaft engine in versions with power ratings from 700 shp (522 kW) to 1,400 shp (1,040 kW). Later UH-1 and related models featured twin engines and four-blade rotors. The Royal Australian Air Force employed the UH-1H until 1989. Iroquois helicopters of No. 9 Squadron RAAF were deployed to South Vietnam in mid 1966 in support of the 1st Australian Task Force. In this role they were armed with single M60 doorguns. In 1969 four of No. 9 Squadron's helicopters were converted to gunships (known as 'Bushrangers'), armed with two fixed forward firing M134 7.62 mm minigun (one each side) and a 7-round rocket pod on each side. Aircrew were armed with twin M60 flexible mounts in each door. UH-1 helicopters were used in many roles including troop transport, medevac and Bushranger gunships for armed support. For more etails of the development, design, operational history and multiple variants, click here. The specifications below are for the UH-1D variant.