Америкалық танк жойғыш M18 Hellcat тарихы

American tank destroyer
The M18 Hellcat was an example of the balancing act among firepower, armor, and mobility in armored fighting vehicle design. Despite its excellent mobility and reasonably powerful main gun, the M18 Hellcat also had drawbacks, including thin armor and a poor high explosive shell for its main gun. Historian Steven J. Zaloga characterized the overall design of the M18 as "poorly balanced" and stated that "the Hellcat's combat record is attributable to the training and dedication of its crews, not to its ill conceived design." He objected to the 3 inch M10 Gun Motor Carriage because it was too heavy and slow for his needs, and later on to the 90 mm M36 Gun Motor Carriage because it was essentially an M10 with a bigger gun. The United States Ordnance Department made several failed attempts to provide such a vehicle using the weapons (the 37 mm, 57 mm, 3 inch, 75 mm and finally the lightweight 76 mm of 1942–1943) and technology available, including mounting the 3 inch gun on the fast M3 Light Tank chassis. The M18 was the end product of a long line of research vehicles aimed at providing the desired machine. In December 1941, the Ordnance Department issued a requirement for the design of a fast tank destroyer using a Christie suspension, a Wright Continental R 975 radial aircraft engine, and a 37 mm gun on the chassis of the Light Airborne Tank T9 as the 37 mm Gun Motor Carriage T42. In April 1942, the Army requested that the 37 mm gun be replaced with a 57 mm and a coil spring suspension be substituted for the Christie suspension as the 57 mm Gun Motor Carriage T49, and authorized the construction of two pilot models. What became the M18 originated in Harley Earl's design studio, part of the Buick Motor Division of General Motors. Previously, basic designs for other kinds of vehicles had mostly originated from within the Ordnance Department. Buick's engineers used a torsion bar suspension that provided a steady ride. The first pilot was delivered in April 1943, and all six were completed by July. Once developed, the Hellcat was tested in the same manner as passenger cars before and after it, at the General Motors Milford Proving Ground. Although the Hellcat was "relatively mature" when it came to automotive performance, problems had to be rectified that included issues with the engine and new automatic transmission, weak front shock absorbers, and the position of the gun to provide more working space for the gunner. For access to the bottom of the engine without having to remove it completely from the hull, it was possible to slide the engine out onto a rail system integrated with the rear hull access door. The 900T Torqmatic transmission had three forward gears, with ranges of up to 16 mph, 12 to 34 mph, and 30 to 60 mph (corresponding to cruising speeds of 12 mph, 25 mph, and 45 mph, respectively), and one reverse gear with a cruising speed of The engine speed was governed such that the vehicle normally could not exceed in third gear. The M18 carried a five man crew, consisting of a commander, gunner, loader, driver, and assistant driver. The driver and assistant driver were seated in the front left and right of the hull, respectively. Uniquely, the driver and assistant driver were provided with identical sets of controls and either could be used to operate the vehicle, but only the driver's set of steering levers could be used as parking brakes. 45 rounds of main gun ammunition were carried, 9 in the turret to the right of the gun, and 18 in each sponson. A .50 caliber M2 Browning machine gun with 800 rounds of ammunition was mounted on the left rear of the turret in a flexible ring mount. Each crew member was provided with an M1 carbine with 90 rounds for self defense, and six Mk 2 grenades, six M50 white phosphorus smoke grenades, and six smoke pots were also carried in the vehicle. The 76 mm gun with standard ammunition could penetrate the frontal turret armor of Panther tanks only at very close ranges,

Another disadvantage of the M18 was its very light armor protection and open topped turret. In testing of the T70 for possible use as a light tank, 9 out of 30 armor piercing .30 caliber bullets penetrated the side of the turret at a range of The open topped turret—a characteristic which it shared with all American tank destroyers—left the crew exposed to snipers, grenades, and shell fragments, however it gave the crew excellent visibility, which was of importance in the killing of tanks, the intent of tank destroyers being primarily ambush weapons. The doctrinal priority of high speed at the cost of armor protection thus led to a relatively unbalanced design.

In July 1943, the AGF directed the Armored Board to consider the T70 for use as a light tank by comparing it with the existing requirements for a light tank. In January 1944, the proposal was rejected because it was felt that the T70 had insufficient armor and secondary armament. The 805th Tank Destroyer Battalion, originally a towed gun unit, re equipped with the M18 during the summer of 1944; it was the only battalion in the Italian campaign to be fully equipped with the M18.

M18s served in tank destroyer battalions and other units supporting US Army infantry divisions in the latter stages of the Pacific war, notably in the Philippines and Okinawa. Tank destroyer battalions equipped with the M18 that served in the Pacific Theater of Operations included the 637th, 670th, and 671st, although only the 637th saw combat, most notably participating in the Battle of Manila where it earned a Distinguished Unit Citation. During the Battle of Okinawa, General Andrew Bruce, who was by then the commander of the 77th Infantry Division, located eight M18s to re equip the Antitank Company of the 306th Infantry Regiment. M18s were not issued to U. S. Marine Corps units.

The M39 Armored Utility Vehicle, which was converted from the M18, was used as a prime mover, infantry carrier, and ammunition carrier.

After World War II, many M18s were sold to other countries. Many intended for European countries under the Mutual Defense Assistance Act were rebuilt and refurbished by Brown & Root in northern Italy in the late 1940s and early 1950s, and bear data plates that indicate those rebuilds. One of the users was Yugoslavia, which received 260 Hellcats during the Informbiro period

The Greek Army received 127 M18s from 1952 to 1954. Initially, these were organized in three Tank Destroyer Regiments numbered 397, 398 and 399. In 1959 the Tank Destroyer Regiments were reorganized in three Tank Destroyer Battalions with the same numbers. Most of the M18s were retired by the end of the 1960s, but a few remained in service until the mid 1970s for training. The Venezuelan military operated M18s beginning in 1954, when they purchased 40. They were refurbished in 1983–1984, and at least one was heavily modernized by a Yugoslavian firm in the 1990s, but it is unclear if more conversions took place.

The only M18 variant produced in significant numbers was the Armored Utility Vehicle M39, a turretless variation used as a gun tractor or command and reconnaissance vehicle. In March 1944, the Ordnance Department authorized the construction of two prototypes; the T41 was a prime mover for the 3 inch Gun M5, while the T41E1 was a command and reconnaissance vehicle that could also be easily converted into a prime mover. The T41E1 configuration was found superior and development of the T41 version was cancelled, although subsequently, the prime mover version of the T41E1 was referred to as the T41, and the command and reconnaissance vehicle as its original designation of T41E1. 640 of the early production M18s that had been returned to the Buick factory for modification were converted into the T41 prime mover configuration between October 1944 and March 1945 by removing the turret and fitting seats for up to eight men in the open fighting space. This version was armed with a single M2 machine gun on a flexible mount. In November 1944, it was standardized as the M39. At the request of the European Theater in early 1945, ten more of the Hellcats were modified into the T41E1 configuration for testing, although they were never standardized. M39s saw combat during the last days of World War II in Europe and during the Korean War, primarily as armored personnel and munitions carriers and were finally declared obsolete on February 14, 1957. About 100 M39s were transferred to the West German Bundeswehr in 1956, where they were used to train the reestablished Panzergrenadier armored infantry units. 76 mm Gun Motor Carriage T86: M18 with the T7 flotation device, using its tracks for water propulsion. The T86E1 variant used propellers for propulsion. 105 mm Howitzer Motor Carriage T87: The T86E1 showed that track propulsion was better and this was used for the T87, which had the same 105 mm T12 howitzer of the T88.