The AH-56A Cheyenne represented the sunset of Lockheed's brief rotorcraft era.
This is the fifth of ten pre-production test prototypes (66-88301) in flight. It is now at the Fort Rucker, Alabama Army Aviation Museum.
Cheyenne was too complex and too time-tolerant. The AH-1 Cobra offered a practical silution to the US Army's needs.
Good view of the Cheyenne's four-bladed pusher propeller. The large ventral fin aided stability and also acted as a skid, with a non-retractable castoring tail wheel at its bottom.
Detail view of the Cheyenne's four-bladed pusher propeller. The large ventral fin aided stability and also acted as a skid, with a non-retractable castoring tail wheel at its bottom.
Inside the Cheyenne gunner's position, showing weapons management panel. A secondary set of instruments to fly the aircraft were also included, along with the flight controls, which are shown at the right in the stowed position.
Diagram of the gunner's position.
Success of the CL-475 increased Army/Navy interest and support for a twin turbine-powered helicopter designated XH-51A. Built under a joint service contract, XH-51A incorporated the rigid rotor non-articulating blades, to simplify control.
Final step before setting on the AH-56A's configuration was provided by the advanced XH-51A Compound helicopter, with a Pratt & Whitney single-shaft military turbojet. This was a test success, with only one major drawback: at full thrust, the J-60 emtied its fuel tank in only six minutes.
The XH-51A demonstrated its ability to self-trim with a large centre of gravity offset in a dramatic manner with a flight test engineer perched at the end of a 15ft side-mounted boom.