M2 Medium Tank
Encyclopedia
The Medium Tank M2 was a United States Army
tank
that was first produced in 1939 by the Rock Island Arsenal
, just prior to the commencement of the war in Europe. Production was 18 M2 tanks, and 94 slightly improved M2A1 tanks, for a total figure of 112. Events in Western Europe
and on the Eastern Front
rapidly demonstrated that the M2 was obsolete, and it was never used overseas in combat; it was used for training purposes throughout the war.
The M2's unique features included an unusually large number of machine gun
s, bullet deflector plates, and sloped armor on the hull front (glacis plate). The main armament was a 37 mm gun, with 32 mm armor; the M2A1 had a 51 mm gun mantlet
. The features of the M2 series development, both good and bad, provided many lessons for U.S. tank designers that were later applied with great success in the M3 Lee
, M4 Sherman and many other armored fighting vehicles.
started work on a new medium tank, based on the design of the M2 Light Tank
. Initially designated the T5, the redesigned model (with a 350 hp R-975 radial engine) was redesignated as the M2 Medium Tank in June, 1939. After the first 18 units had been produced at Rock Island Arsenal and evaluated by the army, the upgraded M2A1 specification was approved with a redesigned turret and a more powerful engine.M3 Medium Tank Vs Panzer III: Kasserine Pass 1943. Rottman, Gordon L. Osprey Publishing, 2008. ISBN 9781846032615
The medium tank M2 was a larger development of the M2 Light Tank
. Many components were common or used a similar design, including the vertical volute spring suspension
which would be used in later tanks as well. Twin-wheeled bogies
were mounted externally, and rubber-bushed and rubber-shoed track proved durable on roads. The initial M2 model was powered by an aircooled Wright R-975 radial engine. For the M2A1, this engine was supercharged to provide an extra 50 hp for a total of 400 hp, and designated as the R-975 C1 radial engine.The illustrated directory of tanks of the world. Miller, David. Zenith Imprint, 2000. ISBN 9780760308929
The M2 had a high superstructure, with a sponson
-mounted machine gun
in each corner. In addition, two more machine guns were fixed in the glacis plate and fired by the driver. Surmounting the superstructure was a small revolving turret
armed with a 37 mm Gun M3 and a coaxial machine gun. The 37 mm gun could penetrate 46 mm of face-hardened armor sloped 30° at a range of 500 yards (457 meters), and 40 mm at 1,000 yards (914 meters). This armament configuration was a hybrid between the sponson-mounted weapons of the Mark VIII Liberty tank
of World War I
vintage, and the combination of turreted cannon, coaxial machine gun and glacis-mounted machine gun that was almost universal in World War II
medium tanks. (Two additional .30-caliber machine guns could be mounted on pintles on either side of the turret for anti-aircraft use, bringing the total to nine—surely a record for any tank brought into service by any army.) The crew consisted of the tank commander, a driver and four gunners. The vehicle provided internal stowage for 200 rounds of 37 mm ammunition and up to 12,250 rounds of .30-caliber
.
Bullet deflector
plates were installed over the rear fenders. The idea behind these plates was that the tank could drive over a trench, and the rear sponson machine guns could then fire onto the plates; the bullets would deflect into the trench or the area directly behind the tank. Like the sponson machine guns themselves, the deflector plates turned out to be useless in modern warfare.
, to manufacture the M2, and the US Government contracted in August, 1940 for 1,000 vehicles to be produced. Events in Europe made obvious that the M2 was obsolete, and the government modified the contract before production began. Instead of M2 medium tanks, the plant would now build 1,000 M3 Grant tanks. Production of the M2 was returned to the Rock Island Arsenal, where 94 M2A1s were eventually built. The M2A1 had slightly better armor and a slightly larger turret than the original M2, since it had the turret from the M3 Light Tank, with gun mantlet
armor 2 inches (51 mm) thick.
an tanks, such as the French
S-35, German Panzer III
and Soviet
BT-7
, which could easily withstand 37 mm hits. The 37 mm main armament of the M2 was equivalent to the 37 mm in the Panzer III, but the BT-7 (45 mm) and the S-35 (47 mm) had more powerful guns. By 1941, Germany had upgunned the Panzer III with a 50 mm L/42 gun, and the Soviets had fielded the vastly superior T-34
, with a 76 mm gun and a sloped 52 mm glacis plate. Given this, the M2 was essentially a stopgap measure until more capable tanks like the M3 Lee
and M4 Sherman
came along in 1942-43. Although 18 M2s and 94 M2A1s were produced, the Ordnance office recommended in 1942 that they should only be used for training purposes, and they were never sent overseas to combat areas.
For combat it was a poor design, with thin armor, inadequate main armament and a high profile. The four sponson
-mounted machine guns proved to be completely unnecessary. But it provided important lessons that were used for the later M3 and M4 medium tanks. In particular, the M2's sloped frontal hull armor (glacis plate) was extremely advanced for a 1939 design, and would become a permanent feature of U.S. tank design. The next medium tank would have to match the German Panzer IV
's 75 mm turret gun. Since no suitable turret had been designed in the US, the Lee was designed first to mount a 75 mm gun in the right sponson, which had been tested on an M2; the experimental vehicle was designated T5E2. The Lee's gun was mounted in a conventional turret on a modified M3, to produce the first Sherman eight months after the first Lee.
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...
tank
Tank
A tank is a tracked, armoured fighting vehicle designed for front-line combat which combines operational mobility, tactical offensive, and defensive capabilities...
that was first produced in 1939 by the Rock Island Arsenal
Rock Island Arsenal
The Rock Island Arsenal comprises , located on Arsenal Island, originally known as Rock Island, on the Mississippi River between the cities of Davenport, Iowa, and Rock Island, Illinois. It lies within the state of Illinois. The island was originally established as a government site in 1816, with...
, just prior to the commencement of the war in Europe. Production was 18 M2 tanks, and 94 slightly improved M2A1 tanks, for a total figure of 112. Events in Western Europe
Battle of France
In the Second World War, the Battle of France was the German invasion of France and the Low Countries, beginning on 10 May 1940, which ended the Phoney War. The battle consisted of two main operations. In the first, Fall Gelb , German armoured units pushed through the Ardennes, to cut off and...
and on the Eastern Front
Eastern Front (World War II)
The Eastern Front of World War II was a theatre of World War II between the European Axis powers and co-belligerent Finland against the Soviet Union, Poland, and some other Allies which encompassed Northern, Southern and Eastern Europe from 22 June 1941 to 9 May 1945...
rapidly demonstrated that the M2 was obsolete, and it was never used overseas in combat; it was used for training purposes throughout the war.
The M2's unique features included an unusually large number of machine gun
Machine gun
A machine gun is a fully automatic mounted or portable firearm, usually designed to fire rounds in quick succession from an ammunition belt or large-capacity magazine, typically at a rate of several hundred rounds per minute....
s, bullet deflector plates, and sloped armor on the hull front (glacis plate). The main armament was a 37 mm gun, with 32 mm armor; the M2A1 had a 51 mm gun mantlet
Gun mantlet
A gun mantlet is an armour plate or shield attached to an armoured fighting vehicle's gun, protecting the opening through which the weapon's barrel projects from the hull or turret armour and, in many cases, ensuring the vulnerable warhead of a loaded shell does not protrude past the vehicle's...
. The features of the M2 series development, both good and bad, provided many lessons for U.S. tank designers that were later applied with great success in the M3 Lee
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...
, M4 Sherman and many other armored fighting vehicles.
Design
Rock Island ArsenalRock Island Arsenal
The Rock Island Arsenal comprises , located on Arsenal Island, originally known as Rock Island, on the Mississippi River between the cities of Davenport, Iowa, and Rock Island, Illinois. It lies within the state of Illinois. The island was originally established as a government site in 1816, with...
started work on a new medium tank, based on the design of the M2 Light Tank
M2 Light Tank
The Light Tank M2 was an American pre-World War II light tank that saw combat with the US Marine Corps 1st Tank Battalion on Guadalcanal in 1942, during World War II. Its service with the 1st Tank Battalion during the Pacific War was its only U.S...
. Initially designated the T5, the redesigned model (with a 350 hp R-975 radial engine) was redesignated as the M2 Medium Tank in June, 1939. After the first 18 units had been produced at Rock Island Arsenal and evaluated by the army, the upgraded M2A1 specification was approved with a redesigned turret and a more powerful engine.M3 Medium Tank Vs Panzer III: Kasserine Pass 1943. Rottman, Gordon L. Osprey Publishing, 2008. ISBN 9781846032615
The medium tank M2 was a larger development of the M2 Light Tank
M2 Light Tank
The Light Tank M2 was an American pre-World War II light tank that saw combat with the US Marine Corps 1st Tank Battalion on Guadalcanal in 1942, during World War II. Its service with the 1st Tank Battalion during the Pacific War was its only U.S...
. Many components were common or used a similar design, including the vertical volute spring suspension
Vertical volute spring suspension
Vertical volute spring suspension is a type of vehicle suspension. It was chiefly used on US armoured fighting vehicles from the 1930s to after the end of the Second World War.-Development:...
which would be used in later tanks as well. Twin-wheeled bogies
Bogie
A bogie is a wheeled wagon or trolley. In mechanics terms, a bogie is a chassis or framework carrying wheels, attached to a vehicle. It can be fixed in place, as on a cargo truck, mounted on a swivel, as on a railway carriage/car or locomotive, or sprung as in the suspension of a caterpillar...
were mounted externally, and rubber-bushed and rubber-shoed track proved durable on roads. The initial M2 model was powered by an aircooled Wright R-975 radial engine. For the M2A1, this engine was supercharged to provide an extra 50 hp for a total of 400 hp, and designated as the R-975 C1 radial engine.The illustrated directory of tanks of the world. Miller, David. Zenith Imprint, 2000. ISBN 9780760308929
The M2 had a high superstructure, with a sponson
Sponson
Sponsons are projections from the sides of a watercraft, for protection, stability, or the mounting of equipment such as armaments or lifeboats, etc...
-mounted machine gun
Machine gun
A machine gun is a fully automatic mounted or portable firearm, usually designed to fire rounds in quick succession from an ammunition belt or large-capacity magazine, typically at a rate of several hundred rounds per minute....
in each corner. In addition, two more machine guns were fixed in the glacis plate and fired by the driver. Surmounting the superstructure was a small revolving turret
Turret
In architecture, a turret is a small tower that projects vertically from the wall of a building such as a medieval castle. Turrets were used to provide a projecting defensive position allowing covering fire to the adjacent wall in the days of military fortification...
armed with a 37 mm Gun M3 and a coaxial machine gun. The 37 mm gun could penetrate 46 mm of face-hardened armor sloped 30° at a range of 500 yards (457 meters), and 40 mm at 1,000 yards (914 meters). This armament configuration was a hybrid between the sponson-mounted weapons of the Mark VIII Liberty tank
Mark VIII (tank)
The Tank Mark VIII or Liberty was an Anglo-American tank design of the First World War. Initially intended to be a collaborative effort to equip France, the UK and the US with a single tank design, it did not come to fruition before the end of the war and only a few were produced.-Early...
of World War I
World War I
World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...
vintage, and the combination of turreted cannon, coaxial machine gun and glacis-mounted machine gun that was almost universal in 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...
medium tanks. (Two additional .30-caliber machine guns could be mounted on pintles on either side of the turret for anti-aircraft use, bringing the total to nine—surely a record for any tank brought into service by any army.) The crew consisted of the tank commander, a driver and four gunners. The vehicle provided internal stowage for 200 rounds of 37 mm ammunition and up to 12,250 rounds of .30-caliber
.30-06 Springfield
The .30-06 Springfield cartridge or 7.62×63mm in metric notation, was introduced to the United States Army in 1906 and standardized, and was in use until the 1960s and early 1970s. It replaced the .30-03, 6 mm Lee Navy, and .30 US Army...
.
Bullet deflector
Deflection (physics)
In physics deflection is the event where an object collides and bounces against a plane surface.In such collisions involving a sphere and a plane, the collision angle formed with the surface normal must equal the bounce angle , \alpha = \beta.Magnetic deflection refers to Lorentz forces acting...
plates were installed over the rear fenders. The idea behind these plates was that the tank could drive over a trench, and the rear sponson machine guns could then fire onto the plates; the bullets would deflect into the trench or the area directly behind the tank. Like the sponson machine guns themselves, the deflector plates turned out to be useless in modern warfare.
Production
Chrysler opened a new tank plant, the Detroit Arsenal Tank PlantDetroit Arsenal Tank Plant
The Detroit Arsenal Tank Plant was the first manufacturing plant ever built for the mass production of tanks in the United States. Established in 1940 under Chrysler, this plant was owned by the U.S. government until 1996. It was designed by architect Albert Kahn...
, to manufacture the M2, and the US Government contracted in August, 1940 for 1,000 vehicles to be produced. Events in Europe made obvious that the M2 was obsolete, and the government modified the contract before production began. Instead of M2 medium tanks, the plant would now build 1,000 M3 Grant tanks. Production of the M2 was returned to the Rock Island Arsenal, where 94 M2A1s were eventually built. The M2A1 had slightly better armor and a slightly larger turret than the original M2, since it had the turret from the M3 Light Tank, with gun mantlet
Gun mantlet
A gun mantlet is an armour plate or shield attached to an armoured fighting vehicle's gun, protecting the opening through which the weapon's barrel projects from the hull or turret armour and, in many cases, ensuring the vulnerable warhead of a loaded shell does not protrude past the vehicle's...
armor 2 inches (51 mm) thick.
Service
The M2 was already obsolete when it entered service. It compared poorly with the latest EuropeEurope
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...
an tanks, such as the French
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
S-35, German Panzer III
Panzer III
Panzer III was the common name of a medium tank that was developed in the 1930s by Germany and was used extensively in World War II. The official German designation was Panzerkampfwagen III translating as "armoured battle vehicle". It was intended to fight other armoured fighting vehicles and...
and Soviet
Soviet Union
The Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....
BT-7
BT-7
The BT-7 was the last of the BT tank series of Soviet cavalry tanks that were produced in large numbers between 1935 and 1940. They were lightly armoured, but reasonably well-armed for their time, and had much better mobility than other contemporary tank designs...
, which could easily withstand 37 mm hits. The 37 mm main armament of the M2 was equivalent to the 37 mm in the Panzer III, but the BT-7 (45 mm) and the S-35 (47 mm) had more powerful guns. By 1941, Germany had upgunned the Panzer III with a 50 mm L/42 gun, and the Soviets had fielded the vastly superior T-34
T-34
The T-34 was a Soviet medium tank produced from 1940 to 1958. Although its armour and armament were surpassed by later tanks of the era, it has been often credited as the most effective, efficient and influential design of World War II...
, with a 76 mm gun and a sloped 52 mm glacis plate. Given this, the M2 was essentially a stopgap measure until more capable tanks like the M3 Lee
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...
and 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...
came along in 1942-43. Although 18 M2s and 94 M2A1s were produced, the Ordnance office recommended in 1942 that they should only be used for training purposes, and they were never sent overseas to combat areas.
For combat it was a poor design, with thin armor, inadequate main armament and a high profile. The four sponson
Sponson
Sponsons are projections from the sides of a watercraft, for protection, stability, or the mounting of equipment such as armaments or lifeboats, etc...
-mounted machine guns proved to be completely unnecessary. But it provided important lessons that were used for the later M3 and M4 medium tanks. In particular, the M2's sloped frontal hull armor (glacis plate) was extremely advanced for a 1939 design, and would become a permanent feature of U.S. tank design. The next medium tank would have to match the German Panzer IV
Panzer IV
The Panzerkampfwagen IV , commonly known as the Panzer IV, was a medium tank developed in Nazi Germany in the late 1930s and used extensively during the Second World War. Its ordnance inventory designation was Sd.Kfz...
's 75 mm turret gun. Since no suitable turret had been designed in the US, the Lee was designed first to mount a 75 mm gun in the right sponson, which had been tested on an M2; the experimental vehicle was designated T5E2. The Lee's gun was mounted in a conventional turret on a modified M3, to produce the first Sherman eight months after the first Lee.