M18 Hellcat

76 mm Gun Motor Carriage M18
Type	Tank destroyer
Place of origin	United States
Specifications
Weight	18 tonnes (40,000 lb)
Length	6.65 m (21.8 ft) (w/ gun) 5.28 m (17.3 ft) (w/o gun)
Width	2.87 m (.42 ft)
Height	2.58 m (8.46 ft)
Crew	5 (Commander, gunner, loader, driver, co-driver)
Armor	5 - 25 mm (0.2 - 1.0 in)
Primary armament	1x 76 mm (76.2 mm) M1A1 gun 45 rounds
Secondary armament	1x .50 cal M2HB machine gun 800 rounds
Engine	Continental R-975-C4, 9 cylinder, radial piston petrol engine 340 hp (253 kW)
Power/weight	18.9 hp/tonne
Suspension	Torsion Bar
Operational range	169 km (105 mi)
Speed	88 km/h (55 mph)

The 76 mm Gun Motor Carriage M18 was an American tank destroyer of World War II. It was often given the nickname Hellcat and is recorded as being the fastest tracked armored fighting vehicle during the war, and for a while after that.

History

In December, 1941, the War Ordnance Department issued a requirement for the design of a fast tank destroyer which used Christie suspension, the Wright Continental R-975 engine and a 37 mm gun. In the light of events in North Africa, it was decided that the 37 mm gun was inadequate and the design was changed to use a 57 mm gun. During a series of prototypes and tests, the design was upgunned to a 75 mm gun, and then to the 76 mm gun. The Christie suspension requirement was also dropped and replaced with a torsion bar suspension. The design was standardized in February 1943 and production began in July. As a ground-up design, the M18 incorporated some new features that US Army soldiers found extremely useful. The Wright R-975 engine could be disconnected from the vehicle in a short period of time and rolled out onto the rear deck of the TD when lowered for repairs. It could be refitted to the drive train in less than an hour. The motor mount is equipped with steel rollers that allow the engine to roll easily on tracks built into the rear deck lid when lowered. Similarly, the transmission can be removed and rolled out onto a front deck plate to allow repairs and inspection. The T70 prototype for the M18 first saw combat in Anzio, Italy, and production versions of the M18 were used in North-West Europe and Italy from the summer of 1944 onwards. In contrast to the 3in Gun Motor Carriage M10, which used the chassis of the Medium Tank M4, the M18 Hellcat was designed from the start to be a fast tank destroyer. As a result it was smaller, lighter and significantly faster, yet still carried the same 76 mm gun as the Sherman 76 models. There was also more internal stowage; the M18 could accommodate a five man crew as well as 45 rounds of ammunition and a M2 Browning machine gun.

M18 Hellcat of the 824th Tank Destroyer Battalion firing in Wiesloch, Germany, 1 April 1945.

The main disadvantages of the M18 (aside from the open top it shared with the M10, which made its crew vulnerable to snipers and shell fragments) was its very light armor and the mediocre performance of its 76 mm gun (which could only penetrate the frontal armor of German Tiger and Panther tanks at point blank range with standard ammunition). The doctrinal priority with high speed at the cost of firepower and armor protection led to an unbalanced design. This problem was remedied with higher velocity ammunition late in the war which allowed the 76 mm gun to achieve greater frontal armor penetration. This HV ammunition was not in great supply however. While the M18 was capable of high road speeds this attribute was difficult to use successfully in combat and the type's thin armor and vulnerability to fire made crews naturally reluctant to push forward into combat with the heavier German tanks. However, most M18 crews found the higher speeds especially useful to flank German tanks which had relatively slow gun traverse speeds. Hellcats were noted for flanking German tanks and shooting into the sides or engine compartments. The crews were generally complimentary of their vehicle's performance and capabilities. There was only one variant of the M18 which saw any real production, the Armored Utility Vehicle M39. It was a turretless variation of the M18 that was used to transport personnel or cargo or as a gun tractor.

Armored Utility Vehicle M39 in Korea, 1952.

The M18 continued in production until October 1944, when the war was nearing its end. 2,507 had been produced by that time, at a unit cost of $57,500. Though all tank destroyer units were disbanded by the U.S. after the war, surplus M18s continued to see limited service. However, the M18 destroyer was a key element during World War II in the Battle of the Bulge, December, 1944.^[1]. Many of the M18s that were given to other countries after WWII were rebuilt and refurbished by Brown & Root in northern Italy in the late 1940s and bear data plates that indicated those rebuilds. The primary example is that of Yugoslavia, which was using them up to the early 1990s. Most of those in Yugoslavian service were manned by the Serbian army of Krajina and used in the Yugoslav conflicts of the early 1990s. One example was used on an armored train named the Krajina Ekspres (Krajina Express).

Related Vehicles

• 105 mm Howitzer Motor Carriage T88 - M18 with its 76 mm M1A1 gun replaced with a 105 mm T12 howitzer, cancelled after end of war.
• Armoured Utility Vehicle T41/M39 - Turretless M18 used for towing, reconnaissance, or transporting infantry, has an .50cal Browning M2 machine gun (900 rounds) for AA defense.
• 76 mm Gun Motor Carriage T86 (Amphibious) - M18 with a specially designed hull to help it float.
  • 76 mm Gun Motor Carriage T86E1 (Amphibious) - Same as T86, but with addition of propellers for propulsion.
  • 76 mm Gun Motor Carriage T87 (Amphibious) - This model had the 105 mm T12 howitzer that was present on the T88. It used its tracks for water propulsion. All work on the three amphibious models was cancelled after the end of the war.

References

External links

• AFV Database: M18, M39
• OnWar
• WWII Vehicles