M6 Heavy Tank
Encyclopedia
The Heavy Tank M6 was an American heavy tank
designed during World War II
. The tank was produced in small numbers and never saw combat.
s for tank development in the interwar years, at the outbreak of World War II the US Army
possessed few tanks, though it had been keeping track of armor use in Europe
and Asia
. Successful employment of armored units in 1939 - 1940, mostly by the Germans
, gave momentum to a number of US tank programs, including a heavy tank program. The United States possessed a massive industrial infrastructure and large numbers of engineers that would allow for mass production of tanks.
Following the Chief of Infantry recommendation from 20 May 1940, the US Army Ordnance Corps
started to work on a 50-ton heavy tank. Initially a multi-turreted
design was proposed, with two main turrets armed with low-velocity T6 75mm (2.95") guns, one secondary turret with a 37 mm gun, and a coaxial .30 caliber (7.62mm) machinegun, and another secondary turret with a 20 mm gun and a coaxial .30 caliber machine gun. Four .30 caliber machineguns were to be installed in ball mounts, two in the glacis
plate and two in the rear corners of the hull. The project was approved on 11 June 1940 and the vehicle received the designation Heavy Tank T1. The design was somewhat similar in concept to multi-turreted breakthrough tanks developed in Europe in the 1920s and throughout the 1930s, such as the British Vickers A1E1 Independent
or the Soviet T-35
. Disadvantages of these "land dreadnoughts", namely their excessive size, difficulty in coordinating actions of the crew, and high production costs, led to abandonment of the concept in Europe.
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 M3 Medium Tank
. Additional armament consisted of two .50 caliber machine guns in a bow mount (operated by the assistant driver), two .30 caliber MGs in the front plate (fired electrically by the driver), one .30 caliber in the commander's cupola and one .50 caliber in a rotor mount in the right rear of the turret roof (operated by the loader). The crew consisted of commander (turret left), gunner (turret right), loader (turret), driver (hull left front), assistant driver (hull right front) and ammunition passer (hull).
One of the main challenges was developing a powerpack
for such a heavy vehicle. The Wright G-200
air-cooled radial
gasoline engine was selected by a committee formed by the Society of Automotive Engineers, but no suitable transmission
was available. The committee recommended developing a hydramatic transmission
, while a possibility of using a torque converter
or an electric transmission was also to be checked.
In 1941 - 1942 three prototypes were built by the Baldwin Locomotive Works
, 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 welded hull and two cast hull. On 26 May 1942 two variants with torque converter transmission were standardized as M6 and M6A1. Standardization of the electric transmission equipped T1E1 as M6A2 was never approved, but manufacturing of the vehicle was nevertheless recommended. It was proposed by the Ordnance Corps that 115 T1E1s would be built for the US Army and 115 M6s and M6A1s for US allies. The 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. By the end of 1942, the Armored Corps were sure that the new M4 Sherman
gave adequate solution for the present and the near future, while being reliable, cheap and much easier to transport.
Work on M6 didn't stop at once. The T1E1 prototype was tested with a T7 90 mm gun and was found to be a satisfactory gun platform, although poor turret layout was noted again. In August 1944 the Ordnance Corps recommended using the T1E1s produced to build 15 77-ton vehicles designated M6A2E1, with thicker (up to 7.5 inches (190.5 mm) vertical protection) glacis armor and a turret developed for the T29 Heavy Tank, armed with a T5E1 105 mm gun. The proposal was rejected by General Eisenhower
. However, by late 1942 main development effort shifted to other projects, one of which eventually resulted in the M26 Pershing
.
On 14 December 1944 the M6 was declared obsolete. Only forty units were 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 War Bond drives and the like. All were eventually scrapped except for a single T1E1 which is on display at the United States Army Ordnance Museum
, Aberdeen, Maryland
.
Some suspension parts were used in the heavy Excelsior A33 Tank
prototypes.
Heavy tank
A heavy tank was a subset of tank that filled the heavy direct-fire role of many armies.Heavy tanks have usually been deployed to breakthrough enemy lines, though in practice have been more useful in the defensive role than in the attack...
designed during World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
. The tank was produced in small numbers and never saw combat.
History and description
Because of limited budgetBudget
A budget is a financial plan and a list of all planned expenses and revenues. It is a plan for saving, borrowing and spending. A budget is an important concept in microeconomics, which uses a budget line to illustrate the trade-offs between two or more goods...
s for tank development in the interwar years, at the outbreak of World War II the US Army
United States Army
The United States Army is the main branch of the United States Armed Forces responsible for land-based military operations. It is the largest and oldest established branch of the U.S. military, and is one of seven U.S. uniformed services...
possessed few tanks, though it had been keeping track of armor use in Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
and Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
. Successful employment of armored units in 1939 - 1940, mostly by the Germans
Nazi Germany
Nazi Germany , also known as the Third Reich , but officially called German Reich from 1933 to 1943 and Greater German Reich from 26 June 1943 onward, is the name commonly used to refer to the state of Germany from 1933 to 1945, when it was a totalitarian dictatorship ruled by...
, gave momentum to a number of US tank programs, including a heavy tank program. The United States possessed a massive industrial infrastructure and large numbers of engineers that would allow for mass production of tanks.
Following the Chief of Infantry recommendation from 20 May 1940, the US Army Ordnance Corps
Ordnance Corps
The United States Army Ordnance Corps is a Sustainment branch of the United States Army, headquartered at Fort Lee, Virginia.-Mission Statement:The U.S...
started to work on a 50-ton heavy tank. Initially a multi-turreted
Gun turret
A gun turret is a weapon mount that protects the crew or mechanism of a projectile-firing weapon and at the same time lets the weapon be aimed and fired in many directions.The turret is also a rotating weapon platform...
design was proposed, with two main turrets armed with low-velocity T6 75mm (2.95") guns, one secondary turret with a 37 mm gun, and a coaxial .30 caliber (7.62mm) machinegun, and another secondary turret with a 20 mm gun and a coaxial .30 caliber machine gun. Four .30 caliber machineguns were to be installed in ball mounts, two in the glacis
Glacis
A glacis in military engineering is an artificial slope of earth used in late European fortresses so constructed as to keep any potential assailant under the fire of the defenders until the last possible moment...
plate and two in the rear corners of the hull. The project was approved on 11 June 1940 and the vehicle received the designation Heavy Tank T1. The design was somewhat similar in concept to multi-turreted breakthrough tanks developed in Europe in the 1920s and throughout the 1930s, such as the British Vickers A1E1 Independent
Vickers A1E1 Independent
The Independent A1E1 is a multi-turreted tank that was designed by the British armaments manufacturer Vickers during the interwar period. Although it only ever reached the prototype stage it influenced many other tank designs....
or the Soviet T-35
T-35
The T-35 was a Soviet multi-turreted heavy tank of the interwar period and early Second World War that saw limited production and service with the Red Army. It was the only five-turreted heavy tank in the world to reach production but proved to be slow and mechanically unreliable...
. Disadvantages of these "land dreadnoughts", namely their excessive size, difficulty in coordinating actions of the crew, and high production costs, led to abandonment of the concept in Europe.
M3 Lee
The Medium Tank M3 was an American tank used during World War II. In Britain the tank was called "General Lee", named after Confederate General Robert E. Lee, and the modified version built with a new turret was called the "General Grant", named after U.S. General Ulysses S. Grant.Design commenced...
. Additional armament consisted of two .50 caliber machine guns in a bow mount (operated by the assistant driver), two .30 caliber MGs in the front plate (fired electrically by the driver), one .30 caliber in the commander's cupola and one .50 caliber in a rotor mount in the right rear of the turret roof (operated by the loader). The crew consisted of commander (turret left), gunner (turret right), loader (turret), driver (hull left front), assistant driver (hull right front) and ammunition passer (hull).
One of the main challenges was developing a powerpack
Powerpack (drivetrain)
Power pack or powerpack is a term used to describe part of a modular powertrain. A powerpack module contains some type of engine and may also contain a transmission and various supporting components...
for such a heavy vehicle. The Wright G-200
Wright R-1820
|-See also:-References:* Bridgman, L, Jane's Fighting Aircraft of World War II. Crescent. ISBN 0-517-67964-7* Eden, Paul & Soph Moeng, The Complete Encyclopedia of World Aircraft. Amber Books Ltd. Bradley's Close, 74-77 White Lion Street, London, NI 9PF, 2002, ISBN 0-7607-3432-1), 1152...
air-cooled radial
Radial engine
The radial engine is a reciprocating type internal combustion engine configuration in which the cylinders point outward from a central crankshaft like the spokes on a wheel...
gasoline engine was selected by a committee formed by the Society of Automotive Engineers, but no suitable transmission
Transmission (mechanics)
A machine consists of a power source and a power transmission system, which provides controlled application of the power. Merriam-Webster defines transmission as: an assembly of parts including the speed-changing gears and the propeller shaft by which the power is transmitted from an engine to a...
was available. The committee recommended developing a hydramatic transmission
Hydramatic
Hydramatic was an automatic transmission developed by both General Motors' Cadillac and Oldsmobile divisions. Introduced in 1939 for the 1940 model year vehicles, the Hydramatic was the first fully automatic mass-produced transmission developed for passenger automobile use.-History:During the...
, while a possibility of using a torque converter
Torque converter
In modern usage, a torque converter is generally a type of hydrodynamic fluid coupling that is used to transfer rotating power from a prime mover, such as an internal combustion engine or electric motor, to a rotating driven load...
or an electric transmission was also to be checked.
In 1941 - 1942 three prototypes were built by the Baldwin Locomotive Works
Baldwin Locomotive Works
The Baldwin Locomotive Works was an American builder of railroad locomotives. It was located in Philadelphia, Pennsylvania, originally, and later in nearby Eddystone, Pennsylvania. Although the company was very successful as a producer of steam locomotives, its transition to the production of...
, 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 welded hull and two cast hull. On 26 May 1942 two variants with torque converter transmission were standardized as M6 and M6A1. Standardization of the electric transmission equipped T1E1 as M6A2 was never approved, but manufacturing of the vehicle was nevertheless recommended. It was proposed by the Ordnance Corps that 115 T1E1s would be built for the US Army and 115 M6s and M6A1s for US allies. The 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. By the end of 1942, the Armored Corps were sure that the new M4 Sherman
M4 Sherman
The M4 Sherman, formally Medium Tank, M4, was the primary tank used by the United States during World War II. Thousands were also distributed to the Allies, including the British Commonwealth and Soviet armies, via lend-lease...
gave adequate solution for the present and the near future, while being reliable, cheap and much easier to transport.
Work on M6 didn't stop at once. The T1E1 prototype was tested with a T7 90 mm gun and was found to be a satisfactory gun platform, although poor turret layout was noted again. In August 1944 the Ordnance Corps recommended using the T1E1s produced to build 15 77-ton vehicles designated M6A2E1, with thicker (up to 7.5 inches (190.5 mm) vertical protection) glacis armor and a turret developed for the T29 Heavy Tank, armed with a T5E1 105 mm gun. The proposal was rejected by General Eisenhower
Dwight D. Eisenhower
Dwight David "Ike" Eisenhower was the 34th President of the United States, from 1953 until 1961. He was a five-star general in the United States Army...
. However, by late 1942 main development effort shifted to other projects, one of which eventually resulted in the M26 Pershing
M26 Pershing
The Heavy Tank M26 Pershing was an American heavy tank briefly used in World War II and in the Korean War. It was named after General John Pershing, who led the American Expeditionary Force in Europe in World War I....
.
On 14 December 1944 the M6 was declared obsolete. Only forty units were 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 War Bond drives and the like. All were eventually scrapped except for a single T1E1 which is on display at the United States Army Ordnance Museum
United States Army Ordnance Museum
The U.S. Army Ordnance Museum is a museum that is in the process of being re-located to Fort Lee, in Fort Lee, Virginia. Its previous building—at Aberdeen Proving Ground in Aberdeen, Maryland—was closed in September 2010, although many outdoor exhibits are still accessible to the...
, Aberdeen, Maryland
Aberdeen, Maryland
As of the census of 2000, there were 13,842 people, 5,475 households, and 3,712 families residing in the city. The population density was 2,166.2 people per square mile . There were 5,894 housing units at an average density of 922.4 per square mile...
.
Some suspension parts were used in the heavy Excelsior A33 Tank
Excelsior A33 Tank
The Tank, Heavy Assault, A33 was a British experimental heavy tank based on the Cromwell design developed in the Second World War when there were concerns as to performance of the Churchill tank.- Development :...
prototypes.
Variants
- T1 - Cast hull, hydramatic transmission. Never built.
- T1E1 - Cast hull, electric transmission. Often unofficially referred to as M6A2. 20 units built.
- T1E2 / M6 - Cast hull, torque converter transmission. 8 units built.
- T1E3 / M6A1 - Welded hull, torque converter transmission. 12 units built.
- T1E4 - Welded hull, hydramatic transmission. Never built.
- M6A2E1 - Uparmored T1E1 with a new turret armed with a T5E1 105 mm gun. Used for testing T29 project armament system.
See also
- G-numbers
- M-numbers
- Panzer VII LöwePanzer VII LöweThe Panzerkampfwagen VII Löwe was a design for a Super Heavy Tank created by Krupp for the Nazi German government during World War II. The project never left the drawing board, and was dropped in late 1942 in favor of the Panzer VIII Maus....
- a German heavy tank design - TOG2TOG2 (tank)The Tank, Heavy, TOG 2 was a prototype British super-heavy tank design produced in the early part of the Second World War in case the battlefields of northern France turned into a morass of mud, trenches and craters as had happened during the First World War....
- a British heavy tank design