Lockheed AH-56 Cheyenne

The Lockheed AH-56 Cheyenne is an attack helicopter developed by Lockheed for the United States Army from its Advanced Aerial Fire Support System program, to field the service's first dedicated attack helicopter. It was a compound helicopter with a four-blade rigid-rotor system, low-mounted wings and a tail-mounted thrusting propeller, driven by a General Electric T64 turboshaft engine, built for a high-speed dash to escort transport helicopters such as the Bell UH-1 Iroquois. In 1966 the Army awarded Lockheed a contract for ten prototypes while ordering the simpler Bell AH-1G Cobra as a stopgap for the Vietnam War. The first flight took place on 21 September 1967 and a production contract followed in January 1968, but a fatal crash and technical problems put development behind schedule. The production contract was canceled on 19 May 1969, the program was canceled on 9 August 1972, and the Army then began the Advanced Attack Helicopter program that led to the Hughes AH-64 Apache.