Agusta Bell Sioux AH Mk I - XT131

The Army Historic Aircraft Flight (AHAF) Sioux, affectionately referred to as the 'clockwork mouse', is from the first batch of fifty ordered by the AAC, built by Agusta Spa at Gallerate in Italy in 1964.

These aircraft were ordered as stop-gaps for the Westland-built Sioux which started coming off the Yeovil production line in the Spring of 1965. The aircraft was taken on charge by the AAC at Middle Wallop on 3 July 1964 and for the duration of her military service was used for flying training and engineering familiarisation at Middle Wallop. XT131 was transferred to the Development and Trials Flight on 18 November 1977 until being subsumed into the AHAF on 11 September 1980.

The aircraft was distinctive for its bubble canopy, exposed welded tube tail boom and saddle fuel tanks. Its two bladed rotor made a 'chop-chop' sound, leading to the nickname 'chopper' for helicopters.

The Sioux is probably the best known of the early military helicopters earning its reputation during the Korean war (1950-1953). It is the most recognised, perhaps due to the success of the 1970 feature film, based on the 1968 novel M*A*S*H (Mobile Army Surgical Hospital) by Richard Hooker and the long-running television series.

The Sioux was the first of many helicopters within the US Army to be named after Native American tribes.