M56 Scorpion


The M56 "Scorpion" self-propelled gun is an American unarmored, airmobile self-propelled tank destroyer, which was armed with a 90 mm 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, the M56 weighed empty and 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 gasoline engine developing at 3,000 rpm, allowing a maximum road speed of and a maximum range of. Twenty-nine rounds of main gun ammunition were carried, and only the small 5 mm thick blast shield was armored.

In service

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, where it was used mainly in direct fire-support. 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 M50 Ontos, which had an armored cabin and was armed with recoilless rifles, in a similar role.
As for foreign operators, Morocco was the only export customer which used M56 Scorpions in 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.

Operators

Former operators

  • : 5 exported in 1965. Used by Tercio de Armada from 1966 to 1970
  • : 1 for evaluation in 1960
  • : 87 received in 1966-1967
  • : 60 ex-American M56 were left as surplus but never used

Survivors

United States
South Korea
New Zealand
  • One example in M&M Military Vehicle Museum under restoration.