Torsion tube over bar at wheels 1 and 4, torsion bar at wheels 2 and 3
Ground clearance
0.32 m (1 ft 1 in)
Fuel capacity
210 litres (46 imp gal; 55 US gal)
Operational range
230 kilometres (140 mi)
Maximum speed
45 kilometres per hour (28 mph)
The M56 "Scorpion" Self-Propelled Gun is an American unarmored, airmobileself-propelledtank destroyer, which was armed with a 90mm M54 gun with a simple blast shield, and an unprotected crew compartment.
History
The M56 was manufactured from 1953 to 1959 by the Cadillac Motor Car Division of General Motors for use by US airborne forces, though the vehicle was eventually used by the Spanish Navy Marines, Morocco and South Korea. With a crew of four (commander, gunner, loader and driver), the M56 weighed 6.4 tonnes (14,000 lb) empty and 7.7 tonnes (17,000 lb) combat-loaded. It had infrared driving lights but no NBC protection and was not amphibious.
The M56 was a fully tracked vehicle with rubber-tired run-flat road wheels and front drive sprocket wheels. It was powered by a Continental AOI-403-5 gasolineengine developing 200 brake horsepower (150 kW) at 3,000 rpm, allowing a maximum road speed of 28 miles per hour (45 km/h) and a maximum range of 140 miles (230 km). Twenty-nine rounds of main gun ammunition were carried, and only the small 5 mm thick blast shield was armored.
In service
M56 Scorpion of 16th Armor, US 173rd Airborne Brigade firing at Viet Cong during Operation Toledo 17 June 1966
The M56 saw combat service with U.S. forces in the Vietnam War. It was deployed with the 173rd Airborne Brigade, which was the only Airborne Brigade deployed with the M56,[1] where it was used mainly in a direct fire-support role. Its function as an air-mobile, self-propelled, anti-tank vehicle was eventually replaced in Vietnam by the troubled but effective M551 Sheridan which had a fully armored turret. The USMC used the Ontos, which had an armored cabin and was armed with recoilless rifles, in a similar role (the running gear of the first Ontos prototype was the same as on the M56, but it was replaced for the production variant).
As for foreign operators, Morocco was the only export customer which used M56 Scorpions in actual combat. M56 Scorpions were deployed against Polisario rebels during the Western Sahara War. A number of examples were made available to South Korea but not used.[citation needed]
Diorama of destroyed M56 at the AAF Tank Museum. Note the prominent rubber tires on the road wheels.The outdoor display of M56 Scorpion 1740950 at VFW Post 2524, Culpeper, VA.
