- Yes
- No
XM551 Test Bed 152 mm gun/launcher
Background:
The development of the M551 Sheridan dates back to after World War II, following the adoption of the M41 Walker Bulldog, which remained in service for a relatively short time, as it was considered too heavy to be classified as a truly light tank with a relatively low cruising range.
Initially, plans were designed for lighter vehicles using the same 76 mm M32 cannon, such as the T71 and T92 light tanks, both of which had air transport capabilities, indicating the US Army’s preference for this means of transport. The T71 never went beyond the mockup phase, and eventually, the T92 became more promising, leading to the termination of the T71 in 1953.
The design of a new air-transportable light tank was reduced from 20 tons to 18 tons, abandoning the idea of a 90 mm cannon in favor of the old 76 mm. The US Army’s push for a new light vehicle came from the adoption of the PT-76 as part of the Soviet land and naval forces, an amphibious light tank equipped with a 76 mm cannon capable of firing High-Explosive Anti-Tank Fin-Stabilized (HEAT-FS) rounds, which was also desired by the US Army. Therefore, in 1958, the T92 development program was canceled.
In 1959, a new attempt began with the first concepts for an Armored Reconnaissance/Airborne Assault Vehicle (AR/AAV) to replace the M41 Walker Bulldog light tank and the M56 Scorpion self-propelled gun. In October of the same year, 12 proposals were submitted to the Ordnance Tank Automotive Command, of which 2 were selected two months later, one from Cadillac Motor Car Division of General Motors Corporation and one from a joint venture between AAI Corporation and Allis-Chalmers Manufacturing Company. The mockups were presented in May 1960.
The candidate from AAI Corp. and Allis-Chalmers Manufacturing Corp. proposed a light tank with 3 crew members weighing about 10 tons, according to the program’s requirements. The proposal from Cadillac Motor Car Division presented a relatively heavier light tank with a total of 4 crew members, where 3 would be positioned in the vehicle’s turret. Eventually, the Cadillac proposal proved more effective than that of AAI Corp. and Allis-Chalmers Manufacturing Company.
In June of the same year, the weight limit was changed from 10 tons to 15 tons, and the proposal from Cadillac Motor Car Division was later accepted, signing a contract to develop the project, which was designated AR/AAV XM551. In August 1961, the Secretary of the Army approved the name “Sheridan” in honor of Major General Philip Sheridan.
In 1961, a test platform was designed and built at the Cleveland Tank Plant, designated XM551 Test Bed, equipping the chassis of an M41 Walker Bulldog with a similar turret from XM551 Pilot number #1. In July 1962, the XM551 Test Bed was transported to Aberdeen Proving Ground, and around 590 rounds were fired with the 152 mm cannon. The XM551 Pilot number #1 was delivered in June of the same year, thus ending the participation of the XM551 Test Bed and marking the beginning of the long history of the M551 Sheridan.
Specifications:
- Weaponry
Primary: XM81 152 mm gun/launcher (main, 20 rounds, 5 missiles)
Secondary: M73 7.62 mm machine gun (coaxial, 3 000 rounds)
- Armor
(f/s/r)
Turret: 25.4, 31.7*/25.4, 31.7*/25.4, 31.7* mm
* respectively refers to Cupola.
Chassis: 28.5* , 63.5*/28.5/28.5, 25.4* (top to bottom) mm
* respectively refers to Front Glassis, Lower Glassis, Middle and Bottom.
- Mobility
Engine: Continental AOS-895-3 six-cylinder air-cooled petrol (500hp)
Max speed: 72 km/h (at 18.8 hp/ST)
Cruising range: 160 km
- Crew
Driver, Gunner, Commander and Loader
- Miscellaneous
Lenght: 8.0 m
Width: 3.3 m
Height: 2.8 m
Weight: 23.295 t
Clearence: 445 mm
Images
representation of the XM551 Test Bed, author: Unknown;
photography of the XM551 Test Bed in Aberdeen Proving Grounds, author: Unknown;
render of the XM551 Test Bed (as T49), author: Wargaming;
Sources
Sheridan: A History of the American Light Tank. vol. 2 (1995) R.P. Hunnicutt. pp. 22-41;
Sheridan: A History of the American Light Tank. vol. 2 (1995) R.P. Hunnicutt. pp. 57-64;
Sheridan: A History of the American Light Tank. vol. 2 (1995) R.P. Hunnicutt. pp. 57-74;
Sheridan: A History of the American Light Tank. vol. 2 (1995) R.P. Hunnicutt. p. 82;
The USA Historical AFV Register: Armored Fighting Vehicles Preserved in the United States of America. v3.1. (2011) Neil Baumgardner. p. 118;
The USA Historical AFV Register: Armored Fighting Vehicles Preserved in the United States of America. v3.1. (2011) Neil Baumgardner. p. 257;
A Compendium of Armaments and Military Hardware. (1987) Christopher Chant. pp. 24-25;
Department of the Army Technical Manual FM 17-80:Tanks, 76-mm Gun M41 and M41A1. (1956) Department of the Army. p. 4;