Lockheed CL-475
CL-475 | |
---|---|
Role | Experimental helicopter |
National origin | United States |
Manufacturer | Lockheed |
Designer | Irven Culver |
First flight | 2 November 1959 |
Status | On display |
Number built | 1 |
The Lockheed CL-475 (registration N6940C)[1] is a two-place, single-engine, light helicopter developed by Lockheed to explore rigid rotor technology. The CL-475 has a three-bladed main rotor and a two-bladed tail rotor. Only one was built.[2]
Design and development
The CL-475 is a two-seat helicopter with a fabric-covered steel and aluminum structure. The glazed cockpit provides side-by-side seating for two occupants. The landing gear is designed in a tricycle configuration, with two large wheels mounted alongside the bottom of the fuselage, and a nosewheel mounted underneath the cockpit. The helicopter is powered by a 140 hp (104 kW), four-cylinder, air-cooled Lycoming O-360-A1A piston engine. Designed to test a rigid-rotor concept, it originally utilized a two-bladed wooden rotor.[2]
After completion at Burbank, the CL-475 was taken to Rosamond Lake on Edwards Air Force Base in the Mojave Desert for testing. It was first flown on 2 November 1959, but the pilot reported severe vibrations. For six months, Lockheed experimented with three and four-bladed wooden rotors, but stability was finally achieved by using metal blades in a three-blade configuration and the addition of a gyroscopic control ring connected directly to the swashplate.[1] In the mid-1960s, the helicopter was test flown by a number of government and military agencies and the military. The stability offered by the rigid rotor control system made the helicopter easy to fly,[2] and the lessons learned from the CL-475 rigid rotor were later used to develop the XH-51 and AH-56A Cheyenne.
In 1975, Lockheed donated the CL-475 to the National Air and Space Museum. The helicopter was loaned to the United States Army Aviation Museum at Fort Rucker, Alabama,[1] but is currently in the museum's storage.[3]
Specifications
Data from [2]
General characteristics
- Crew: 2
Performance
See also
Related development
Related lists
References
Notes
Bibliography
- Francillon, René J. (1982). :Lockheed Aircraft since 1913. London: Putnam & Company. ISBN 0-370-30329-6.
- Francillon, René J. Lockheed Aircraft Since 1913. Annapolis, Md: Naval Institute Press, 1987. ISBN 9780851778051