M56 Scorpion

Infobox Weapon
name= M56 Scorpion


caption= M56 Scorpion preserved at the American Armored Foundation Tank Museum in Danville, Virginia.
origin= USA
type= Self-propelled gun
is_vehicle=yes
service=
used_by=USA, ESP, MAR
wars= Vietnam War
designer=
design_date=
manufacturer=Cadillac Motor Car Division of General Motors
unit_cost=
production_date=1953–1959
number=
variants=
weight= 7.1 tonnes
length= 4.55 m (excluding gun)
part_length=
width= 2.57 m
height=2 m over gun shield
diameter=
crew=4 (commander, gunner, loader and driver)
armour= unarmored except for blast shield
primary_armament=90mm M54
29 rounds
secondary_armament=
engine=Continental A01-403-5 gasoline engine
engine_power=200 hp
transmission= Allison CD-150-4, 2 ranges forward, 1 reverse
payload_capacity=
fuel_capacity= 210 l
pw_ratio=
suspension=Torsion tube over bar at wheels 1 and 4, torsion bar at wheels 2 and 3
clearance= 0.32 m
vehicle_range= 230 km (140 mi)
speed= 45 km/h (28 mph)
guidance=

The M56 Scorpion was an unarmoured 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.

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 tons empty and 7.7 tons 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 brake horsepower at 3,000 rpm, allowing a maximum road speed of convert|28|mi/h|km/h|abbr=on and a maximum range of convert|140|mi|km. Twenty-nine rounds of main gun ammunition were carried, and only the blast shield was armored. The M56 saw service with U.S. forces in the Vietnam War, where its function (air portable, self-propelled, anti-tank vehicle) was replaced by the troublesome but effective M551 Sheridan which had a fully armoured turret.

The USMC used the Ontos which had an armoured cabin and recoilless rifles, and was based on the running gear of the M56. The current Stryker gun system has a similar role as lightweight gun support, but is too heavy and large to be dropped by parachute or carried by helicopter, or even by C-130. 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.

A well preserved example can be found in a city park in Auburn, Washington and next to a park in Elmwood Park, New Jersey. A restored M56 is at the American Armored Foundation Tank Museum in Danville, Virginia, along with a diorama of a destroyed M56.

References

*cite book |last= Foss|first= Christopher F.|title= Jane's Pocket Book of Tanks and Armored Fighting Vehicles |year= 1974|origyear= 1972|publisher= Collier Books|id=LC Control No. 73-15286|pages= 153
* [http://afvdb.50megs.com/usa/m56spat.html 90 mm Self-propelled Gun M56 Scorpion]

External links

* [http://www.aaftankmuseum.com/ American Armored Foundation Tank Museum Website]