M56 Scorpion

The M56 Scorpion was an unarmored American self-propelled anti-tank gun, which featured a 90mm M54 gun with a simple blast shield, and unprotected crew compartment. It was meant to be transported by helicopter or by air drop.

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 and Morocco as well. With a crew of four (commander, gunner, loader and driver), the M56 weighed 6.4 t empty and 7.7 t combat-loaded. It had infrared driving lights but no Nuclear, Biological and Chemical (NBC) protection system 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 A01-403-5 gasoline engine developing 200 bhp at 3,000 rpm, allowing a maximum road speed of 28 mph and a maximum range of 140 mi. Twenty-nine rounds of main gun ammunition were carried, and only the 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 a direct fire-support role. Its function as an air portable, 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).

With the retirement of the Sheridan, current US airborne troops do not have a self-propelled gun system that can be delivered by air drop.

Survivors



 * A well preserved M56 can be found in a city park in Auburn, Washington.
 * An M56 is on display as a memorial in Tillicum Park. Forks, Washington.
 * An M56 is on display next to a park in Elmwood Park, New Jersey.
 * A restored M56 is on display at the American Armored Foundation Tank Museum in Danville, Virginia, along with a diorama of a destroyed M56.
 * An M56 is on display (along with an M60 tank) in front of the Duluth, Georgia American Legion post.
 * An M56 is on display (along with an M41 Walker Bulldog) outside Veterans Memorial Stadium in Cedar Rapids, Iowa.
 * An M-56 Scorpion is on Outdoor Display at the 82nd Airborne War Memorial Museum at Ft. Bragg, N.C.
 * An M56 is on display at the American Legion Post in Gunthersville, AL.
 * An M-56 Scorpion is on display at the Boyd County War Memorial in Armco Park in Summit, KY.
 * An M-56 arrived at Forest Hill Station, home of the U.S. Army Cadet Corps in Millersburb, KY, on July 19th, 2012.
 * An M-56 Scorpion is on display in front of VFW Post 2524 Culpeper VA.