M6 heavy tank
This article includes a
|Heavy Tank M6|
|Place of origin|
|In service||trials only|
|Wars||World War II|
|Designer||US Army Ordnance Corps|
|Mass||126,500 lb (57.4 tonnes) combat loaded|
|Length||27 ft 8 in (8.43 m) gun forward|
|Width||10 ft 3 in (3.12 m) over track armor|
|Height||9 ft 10 in (3.0 m) to turret roof|
|Crew||6 (commander, gunner, driver, assistant driver, loader, assistant loader)|
|1 × |
|2 × |
2 × .30
|Engine||1,823 in3 (29.88 L) |
825 hp at 2,300 rpm
|Ground clearance||20.5 in (52 cm)|
|Fuel capacity||477 US gallons (1,810 L)|
|100 miles (160 km)|
|Speed||22 mph (35 km/h)|
Because of limited
Initially, a multi-
By October, the US developers reached the same conclusion as their European counterparts. The armament was changed to a single vertically stabilized 3-inch (76.2 mm) gun and a coaxial 37 mm gun in a single three-man turret with both manual and electric traverse. The turret had a commander's cupola identical to that of the
One of the main challenges was developing a
The project was first publicly disclosed in August 1940 when the Army awarded
The first T1E1 was delivered to the Army in December 1941. From 1941 to 1942, three prototypes were built. One with electric transmission and two with torque converter transmission. Variants with hydramatic transmission were never completed. The prototypes also differed in hull assembly method— one had a welded hull and two had cast hulls.
On 26 May 1942, two variants with torque converter transmission were standardized as M6 and M6A1. Standardization of the electric transmission equipped T1E1 as the M6A2 was never approved, but the manufacturing of the vehicle was nevertheless recommended. It was proposed by the Ordnance Corps that 115 T1E1s would be built for the US Army for "extended service tests", between that and Services of Supply instruction to increase production with the balance going to aid US allies, this would mean 50 M6s and 65 M6A1s built for the British. Production started in December 1942.
Some minor changes were introduced in the production vehicles: the cupola was replaced by a double-door hatch with a ring mount, the machine gun in a rotor mount and the left front machine gun were removed.
However, by the time the M6 was ready for production, the Armored Corps had lost interest in the project. The advantages the M6 offered over medium tanks – its much thicker armor and slightly more powerful gun – were offset partly by the shortcomings of the design – such as very high silhouette, awkward internal layout and reliability problems – and partly by logistical concerns due to its weight.
In early 1942, the Ordnance Department set a production target of 250 a month, with Fisher as a second contractor to meet a planned expansion in the size of the army. However, by September, the focus had changed, with tank production scaled back and more aircraft for the USAAF. Under this new "Army Supply Program", the M6 production was cut from 5,000 to a little over 100.
By the end of 1942, the Armored Corps were of the opinion that the new
Production M6 and pilot M6A1 examples were evaluated at Fort Knox in the early part of 1943. The reports were critical of the awkward and inefficient crew stations, and the superfluous 37mm gun. However, in October, the tank had performed well enough at
The Ordnance Corps had expected the 75 mm gun to be lacking, and the T1E1 prototype was tested with a T7 90 mm gun and was found to be a satisfactory gun platform, although the poor turret layout was again noted. By this point, the M6 had been cancelled.
In August 1944, the Ordnance Corps recommended modifying the T1E1s to build 15 specially armored and armed tanks to meet a need for attacking heavily fortified areas. These 77-ton vehicles – designated M6A2E1 – with thicker (equivalent to 7.5-inch (190 mm) vertical protection) glacis armor and a turret developed for the
On 14 December 1944, the M6 was declared obsolete. Only 40 had been produced and they never left US soil. Several toured the United States for propaganda purposes, where they gave performance displays (such as car crushing) at
The British used the suspension of the M6 in the first of their two