Fall of Nations/Vehicles/M6 McClellan/Historical Information

The M6 heavy tank was an American heavy tank designed during the opening years of the Second World War. Considered to be a step forward for the United States military, it was approved for combat service in 1942. Unlike its contemporary designs, such as the M4 Sherman and the M5 Stuart, the M6 would not see any large scale production or service overseas. For the duration of the war, the vehicles would be used as test beds for future developments.
==Development and Demise==
Having fallen way behind the rest of the world with its development of armored vehicles, the United States military began a program to develop vehicles to fight the upcoming war in the late 1930s. While light and medium tank programs were underway, there was a lack of interest in a heavy tank program for the military. By 1940, the military had watched the usage of tanks in the European theatre, particularly by France and Germany, and ramped up its armor development which included the start of a heavy tank program.
The US Ordnance Corps approved the requirements for the design and construction of a 50-ton heavy tank, designating it the Heavy Tank, T1. The initial design was a multi-turreted tank akin to vehicles seen in the early part of the 1930s in Europe, featuring two main turrets armed with 75 mm guns, two smaller turrets with either a 20 mm or a 37 mm gun respectively and coaxial .30 caliber machine guns, and four .30 caliber machine guns in ball mounts. As was found in Europe, Ordnance Corps quickly found this type of vehicle unsuited for combat and began developing a more contemporary design.
Redesigns for the vehicle saw the switch to a single-turret armed with a high-velocity 76 mm gun and a coaxial 37 mm gun. In order to find parts commonalities with other vehicles being designed, several elements from the M3 medium tank were integrated into the tank such as its cupola, sighting systems, and part of the running gear. The vehicle would be manned by a crew of six men and have numerous built-in machine guns for infantry support and self-defense. By late-1941, the first prototype had been built and sent for testing at Aberdeen Proving Ground and would be followed by two more, which only differed in production method. By May of 1942, the T1E2 and T1E3 prototypes were officially accepted into service and designated the Heavy Tank, M6 and Heavy Tank, M6A1 respectively.
While changes were being made to the designs for full-scale production, the newly established Army Ground Forces lost interest in the tank, ending the planned 5,000 vehicle production run. The number of vehicles allowed for production dropped to 40 by 1943, where no further vehicles would be built. The main reasons for the end to the M6 program was weight limitations on cranes in American ports, the perceived adequacy of the M4 Sherman, and its advantages over the M4 Sherman were marred by its defects. Tests of the vehicle conducted at Fort Knox found the vehicle's to have poor crew positioning, issues with reliability, and a useless 37 mm gun. In 1943, however, the vehicle was still deemed adequate enough to proceed with more tests at Aberdeen.
The last tests done with the M6 heavy tank were conducted between 1943 and 1945. The first saw a prototype T1E1, unofficially designated the M6A2, armed with a prototype 90 mm T7 gun and fitted with extra armor undergo trials were it was found to be a good gun platform, but nothing further came from this. The end for the M6 came when Ordnance proposed a new variant of the vehicle that could be armed with the experimental 105 mm T5E1. Fifteen prototypes of this variant would be constructed and, designated the M6A2E1, would end up being a test bed for the new T29 heavy tank program. By 1944, the M6 was deemed obsolete and retired from service completely, never leaving the United States and only used for training operations and propaganda tours. Out of the 40 vehicles, only one survives which was the T1E1 prototype tested by Aberdeen in 1944.
==Variants==
*T1 (original design) - Multi-turreted design, cast hull. Never built.
*T1 (official design) - Cast hull, hydramatic transmission. Never built.
*T1E1 / M6A2 (unofficially) - Cast hull, electrical transmission. 20 built.
*T1E2 / M6 - Cast hull, torque converter transmission. 8 built.
**M6E1 - Late-war proposal to mount the turret of the M26 Pershing onto the hull of the M6. Never built.
*T1E3 / M6A1 - Welded hull, cast turret, torque converter transmission. 12 built.
*T1E4 - Welded hull, hydramatic transmission. Never built.
*M6A2E1 - Uparmored T1E1 with new turret mounting the 105 mm gun T5E1. 15 units converted.
==Historical Gallery==
M6 heavy tank - Reference 33.png|Artist representation of the original T1 concept. (original artist: https://www.deviantart.com/tinkertanker44432)
M6 heavy tank - Reference 32.jpg|A side profile of one of the original T1E2 prototypes. Circa 1942.
M6 heavy tank - Reference 18.jpg|An M6A1 on a training exercise with an M5 light tank.
M6 heavy tank - Reference 31.jpg|A pre-production M6 taken out of Fort Knox to smash some cars at a War Bond event. Circa 1942.
M6 heavy tank - Reference 30.png|The only known photo of an M6A2 and a Tiger I next to each other. Note, the vehicle in this image is armed with a 90 mm gun and standardized armor. The Tiger in the background is likely Tiger 712. Circa 1943.
M6 - Reference 1.jpg|A fully armed M6A1 ready for testing. Circa 1943.
M6 heavy tank - Reference 26.jpg|A side profile of an M6A2 armed with the 90 mm M3 gun. This vehicle had its front hull armor removed during testing. Circa 1943.
M6 heavy tank - Reference 19.jpg|An artist's representation of the original proposal for the M6A2E1.
M6 heavy tank - Reference 5.jpg|One of the two prototype M6A2E1s at Aberdeen. Circa 1945.
M6 heavy tank - Reference 15.jpg|The only surviving vehicle, a T1E1/M6A2 model, before its move to Fort Lee, Virginia after the closure of the Army Ordnance Museum. It is not known if this vehicle was the one used for testing with the 90 mm gun.