M47 Medium Tank (USA)
At the start of the Korean War, the standard US tank was the M26/M46 medium tank. A new medium tank, the T42 was then in development, and the US Army was caught in a dilemma between continuing with the M26/M46 line with its reliability and familiarity, or go for the new T42 tank when it became available. The success of the communist North Korea, armed as it was with T-34/76 and T-34/85s from the Soviet Union made the acquisition of a new medium tank a major priority. The final decision was something of a surprise as it called for the mating of the T42 turret with the proven chassis of the M46 medium tank. Changes were necessary to the hull to accommodate a new engine cooling system and electrical harness and the tank also had a new turret rangefinder and 90mm gun. Modified versions of the M46 were hastily put through a series of trials, with the hull modifications being tested first, and these were accepted into service on the M46A1. The new tank with the T42 turret on the fully modified hull was designated M47. The M47's 90mm T119 high velocity gun was of a new design, developed in parallel with the British 20pdr tank gun and had a larger chamber than the M46's 90mm M3A1 gun and had a concentric recoil system as the previous gun had actually been developed from an anti-aircraft gun. There were problems with the rangefinder though, and this led to a delay in testing. Trials were eventually conducted at the Aberdeen Proving Ground and Camp Irwin and were generally successful, although deficiencies were found in the hydraulic traversing mechanism. On 16 April 1952 the Department of the Army announced it had accepted the M47. Production started almost immediately but the M47 was unavailable in sufficient numbers to see action in Korea and so started to go to units in Germany. A total of 8,576 M47s were built at the Detroit Arsenal (run by Chrysler) and by the American Locomotive Company at Schenectady, NY. The turret (from the T42) was cast, with the turret bustle housing the radios and a storage box mounted on the outside. The commander's cupola had a single hatch, five vision blocks and a 0.5in machine gun on the turret roof. The hull (derived from the M46) was constructed of welded flat plate armour plate and castings, and belly escape hatches were provided below both driver and co-driver positions. The engine was a Continental AV-1790-5B (later 7 or 7B) which was separated from the fighting compartment by an armoured bulkhead and produced 810bhp at 2,800rev/min and had a small auxiliary engine to charge the batteries. The transmission was a crossdrive unit and had initial problems due to the production changes made to speed up deployment of the M47. Reliability was vastly improved later with a tightening of quality controls in the production process. Suspension was of the torsion bar type, and there were six pairs of rubber-tyred road wheels, with a characteristic gap between the first two as the first pair were on leading arms, the rest being on trailing arms. There was also a small idler wheel between the final road wheel and the rear sprocket to maintain track tension. The fire control system was of an integrated type, the first of its kind, and therefore had problems. It was of a stereoscopic type, calibrated up to 5,000yds. A ballistic drive connected the integral computer in the rangefinder to the commander's periscope, while a superelevation transmitter connected the rangefinder to the gun. The superelevation transmitter required its own power supply, necessitating a 33lb inverter, and it was difficult to train troops to the required proficiency. The M47 was only in US service for a short time, being replaced by the M48, but it served an important part in the NATO tank force as large numbers were given to allies in military assistance programmes. It saw combat at Suez with the French army, with Pakistan in the 1965 war with India, in 1967 with the Royal Jordanian Army against Israel, with the Turkish Army in the 1974 invasion of Cyprus and in 1977 with Ethiopia in the Ogaden War.
Hull length: 6.36m. Hull width: 3.51m (with skirts). Height: 2.95m. Crew: 5. Ground Clearance: 0.47m. Weight: 46,000kg (combat). Ground pressure: 0.935kg/sq.cm. Max speed: 48km/h. Max range (internal fuel): up to 130km on road. Armament: 90mm rifled main gun, 1 x 0.3in MG coaxial, 1 x 0.3in MG in hull front, 1 x 0.5in MG on turret roof.
Modern American Armour
, Zaloga, Stephen & Loop, James, Arms and Armour Press, London, 1982.
How to cite this article: Antill, P. (8 March 2001), M47 Medium Tank (USA), http://www.historyofwar.org/articles/weapons_m47.html