The UH-1 Huey Iroquois is a multipurpose utility helicopter. It was manufactured by Bell Helicopter Textron. Its maiden flight was on the 22nd of October 1956 but it was introduced commercially in 1959. Its primary users are the United States Army, Japan Ground Self-Defense Force, Royal Australian Air Force, and Philippine Armed Forces. The Huey, as it is commonly known, became famous for its use in the Vietnam War. The “U” stands for Utility as compared to Attack and the Cargo helicopters. In 1959, the Huey was first used by the military and in 1962 it went into triservice production and became the UH-1. The UH-1 has a lot of variants. The United States Military variants are the XH-40 which is the initial Bell 204 prototype; the YH-40 which the sixth pre-production aircraft; the HU-1A which is known initially as the Bell 204 production model but redesignated in 1962 as the UH-1A; the HU-1B which is an upgraded HU-1A having various external and rotor improvements and in 1962 it was redesignated as the UH-1B; the UH-1C which is similar to the UH-1B; the YUH-1d which is a pre-production prototype of the UH-1D; the UH-1D which is initially the Bell 205 production model and the long fuselage version of the Bell 204.