AMT-WWII_10 – M4A1 Medium TANK…
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. In theUnited Kingdom, the M4 was named after Union General William Tecumseh Sherman, following the British practice of naming their American-built tanks after famous American Civil War generals. Subsequently the British name found its way into common use in the U.S.
The Sherman evolved from the Grant and Lee medium tanks, which had an unusual side-sponson mounted 75 mm gun. It retained much of the previous mechanical design, but added the first American main 75 mm gun mounted on a fully traversing turret, with a gyrostabilizer enabling the crew to fire with reasonable accuracy while the tank was on the move. The designers stressed mechanical reliability, ease of production and maintenance, durability, standardization of parts and ammunition in a limited number of variants, and moderate size and weight. These factors made the Sherman superior in some regards, to the German light and medium tanks that had swept across Europe in the blitzkrieg campaigns of 1939-41, and which still made up the majority of German panzer –albeit usually in up-gunned and up-armored variants—forces in the later stages of the war. The Sherman ended up being produced in large numbers and formed the backbone of most Allied offensives, starting in late 1942. The original Shermans were able to defeat the relatively small German tanks such as the Panzer II and III they faced when first deployed in North Africa. Later, they found themselves seriously outmatched against newer up-gunned and up- armoredPz.Kpfw. IV and Panther medium tanks and wholly inadequate against the armor and range of the Tiger I and later Tiger II heavy tanks, suffering high casualties against their heavier armor and more powerful 88 mm and 75 mm cannons. Mobility, mechanical reliability and sheer numbers, supported by growing superiority in supporting fighter-bombers and artillery, offset these disadvantages to an extent. Later versions of the Sherman introduced 76 mm guns, giving them better armor penetration than the original 75 mm gun, though still insufficient at range against late war German heavy tanks. Producing more Shermans was favored over rushing adoption of the heavier M26 Pershing, which was developed too late to play a significant role in the war. In the Pacific Theater, the Sherman was used chiefly against Japanese infantry and fortifications; in their rare encounters with lighter Japanese tanks with weaker armor and guns, the Sherman’s superiority was overwhelming.
Production of the M4 exceeded 50,000 units, and its chassis served as the basis for numerous other armored vehicles such astank destroyers, tank retrievers, and self-propelled artillery. Only Mikhail Koshkin’s design of the Soviet T-34 tank was ultimately produced in larger numbers during World War II. Many German generals and many historians considered the T-34 the best tank of the war, but even so the Russians recognized the Sherman’s particular advantages when they used them in certain niche situations.
The Sherman would finally give way to post-war tanks developed from the M26. Various original and updated versions of the Sherman would continue to see combat effectively in many later conflicts, including the Korean War, the Arab-Israeli Wars, andIndo-Pakistani Wars into the late 20th century, against the T-34 and sometimes much more contemporary Soviet tanks.
U.S. design prototype
The U.S. Army Ordnance Department designed the Medium Tank M4 as a replacement for the M3 Lee and Grant Medium Tanks. The M3 was an up-gunned development of the M2 Medium Tank of 1939, itself derived from the M2 Light Tank of 1935. The M3 was developed as a stopgap measure until a new turret mounting a 75 mm gun could be devised. While it was a big improvement when tried by the British in Africa against early German panzers, the placement of a 37 mm gun turret on top gave it a very high profile, and the unusual inflexible side-sponson mounted main gun could not be aimed across the other side of the tank.
Detailed design characteristics for the M4 were submitted by the Ordnance Department on 31 August 1940, but development of a prototype had to be delayed while the final production designs of the M3 were finished and the M3 entered full-scale production. On 18 April 1941, the U.S. Armored Force Board chose the simplest of five designs. Known as the T6, the design was a modified M3 hull and chassis, carrying a newly designed turret mounting the Lee’s main gun. This became the Sherman.
The Sherman’s reliability benefited from many features first developed in U.S. light tanks during the 1930s, including vertical volute spring suspension, rubber-bushed tracks, and rear-mounted radial engine with drive sprockets in front. The designated goals were to produce a fast, dependable medium tank able to support infantry, provide breakthrough striking capacity, and defeat any tank then in use by the Axis nations, though it would later fall short against the much larger tanks eventually deployed by Germany.
The T6 prototype was completed 2 September 1941. Unlike later M4s, the hull was cast and had a side hatch, which was eliminated from production models. The T6 was standardized as the M4 and production began in October.
As the US approached entry in WWII, armored employment was doctrinally governed by FM 100-5 Operations (published May 1941, the month following selection of the M4 tank’s final design). That FM stated that: „The armored division is organized primarily to perform missions that require great mobility and firepower. It is given decisive missions. It is capable of engaging in all forms of combat, but its primary role is in offensive operations against hostile rear areas.” In other words, the M4 was envisioned to primarily fill the role of a cruiser tank — although the US Army did not use that doctrinal term. The M4 was not primarily intended as an infantry support tank; in fact, FM 100-5 specifically stated the opposite. It placed tanks in the „striking echelon” of the armored division, and placed the infantry in the „support echelon”. Neither was the M4 primarily intended for tank versus tank action. Doctrinally, anti-tank engagements were the primary role of tank destroyers. The field manual covering the use of the Sherman (FM 17-33, „The Tank Battalion, Light and Medium” of September 1942) devoted one page of text and four diagrams to tank versus tank action (out of 142 pages). This early armored doctrine was heavily influenced by the sweeping initial successes of the German blitzkrieg tactics. Unfortunately, by the time M4s reached combat in significant numbers, battlefield demands for infantry support and tank versus tank action far outnumbered the occasional opportunities for cruiser tanks.
Although envisioned primarily as a cruiser-type tank, US doctrine did also contemplate the M4’s use in other roles. Unlike some other nations, which had separate medium tank designs tailored specifically for anti-tank roles (e.g., the German PzKw III) and support roles (the PzKw IV), the US intended the M4 to fulfill all roles. Although not optimized for tank versus tank engagements or infantry support, the M4 was capable of performing these missions to varying degrees. In the Pacific Theater, the Sherman was used chiefly against Japanese infantry and fortifications; in their rare encounters with lighter Japanese tanks with weaker armor and guns, the Shermans were superior.
U.S. production history
The first production began with the Lima Locomotive Works on the assembly line set for tanks for British use. The first production Sherman was given over to the US Army for evaluation and it was the second tank of the British order that went to London. Named Michael probably after Michael Dewar, head of the British Tank mission in the US, it was displayed in London and is now an exhibit at Bovington tank Museum
In World War II, the U.S. Army ultimately fielded 16 armored divisions, along with 70 independent tank battalions. A third of all U.S. Army tank battalions, and all six U.S. Marine Corps tank battalions, were deployed to the Pacific Theater of Operations (PTO). However, prior to September 1942, President Franklin D. Roosevelt had announced a production program calling for 120,000 tanks for the Allied war effort, which would have created 61 armored divisions. Although the American industrial complex was not affected by enemy aerial bombing nor submarine warfare as was Japan, Germany and, to a lesser degree, Great Britain, the enormous drain of steel for tank production had been diverted to warships and other naval vessels. The use of steel for naval construction amounted to the equivalent of approximately 67,000 tanks; and consequently only about 53,500 tanks were produced during 1942 and 1943.
The U.S. Army had seven main sub-designations for M4 variants during production: M4, M4A1, M4A2, M4A3, M4A4, M4A5, and M4A6. These designations did not necessarily indicate linear improvement: for example, A4 was not meant to indicate it was better than the A3. These sub-types indicated standardized production variations, which were in fact often manufactured concurrently at different locations. The sub-types differed mainly in engines, although the M4A1 differed from the M4 by its fully-cast upper hull; the M4A4 had a longer engine system that required a longer hull, a longer suspension system, and more track blocks; M4A5 was an administrative placeholder for Canadian production; and the M4A6 had an elongated chassis, but fewer than 100 of these were produced.
While most Shermans ran on gasoline, the M4A2 and M4A6 had diesel engines: the M4A2 with a pair of GMC 6-71 straight six engines, the M4A6 a Caterpillar RD1820 radial. These, plus the M4A4, which used the Chrysler A57 multibank engine, were mostly supplied to Allied countries under Lend-Lease. „M4” can refer specifically to the initial sub-type with its Continental radial engine, or generically, to the entire family of seven Sherman sub-types, depending on context. Many details of production, shape, strength and performance improved throughout production, without a change to the tank’s basic model number: more durable suspension units, safer „wet” ammunition stowage, and stronger armor arrangements, such as the M4 Composite, which had a cast front hull section mated to a welded rear hull. British nomenclature differed from that employed by the U.S.
A 24-volt electrical system was used in the M4.
|M4(105)||105 mm howitzer||welded||gasoline Continental R975 radial|
|M4 Composite||75 mm||cast front welded sides||gasoline Continental R975 radial|
|M4A1(76)W||cast||gasoline Continental R975 radial|
|M4A2||75 mm||welded||diesel GM 6046 (2×6-71 inline)|
|M4A3W||75 mm||welded||gasoline Ford GAA V8|
|M4A3E2 „Jumbo”||75 mm (some 76 mm)||welded||gasoline Ford GAA V8|
|M4A3E8(76)W „Easy Eight”||76 mm||welded||gasoline Ford GAA V8|
|M4A4||75 mm||welded lengthened||gasoline Chrysler A57 5×6-cyl inline|
|M4A6||75 mm||cast front welded sides lengthened||diesel Caterpillar D200A radial|
Early Shermans mounted a 75 mm medium-velocity general-purpose gun. Although Ordnance began work on the Medium Tank T20 as a Sherman replacement, ultimately the Army decided to minimize production disruption by incorporating elements of other tank designs into the Sherman. Later M4A1, M4A2, and M4A3 models received the larger T23 turret with a high-velocity 76 mm M1 gun, which reduced the number of HE and smoke rounds carried and increased the number of anti-tank rounds. Later, the M4 and M4A3 were factory-produced with a 105 mm howitzer and a new distinctive mantlet in the original turret. The first standard-production 76 mm gun Sherman was an M4A1, accepted in January 1944, and the first standard-production 105 mm howitzer Sherman was an M4 accepted in February 1944.
In June–July 1944, the Army accepted a limited run of 254 M4A3E2 Jumbo Shermans, which had very thick armor, and the 75 mm gun in a new, heavier T23-style turret, in order to assault fortifications. The M4A3 was the first to be factory-produced with the HVSS (horizontal volute spring suspension) suspension with wider tracks to distribute weight, and the smooth ride of the HVSS with its experimental E8 designation led to the nickname Easy Eight for Shermans so equipped. Both the Americans and the British developed a wide array of special attachments for the Sherman; few saw combat, and most remained experimental. Those that saw action included the bulldozer blade for the Sherman dozer tanks, Duplex Drivefor „swimming” Sherman tanks, R3 flamethrower for Zippo flame tanks, and the T34 60-tube Calliope 4.5″ rocket launcher for the Sherman turret. The British variants (DDs and mine flails) were among „Hobart’s Funnies”, named after their commander, Percy Hobart of the 79th Armoured Division.
The M4 Sherman’s basic chassis was used for all the sundry roles of a modern mechanized force: roughly 50,000 Sherman tanks, plus thousands more derivative vehicles under different model numbers. These included M32 and M74 „tow truck”-style recovery tanks with winches, booms, and an 81 mm mortar for smoke screens; M34 (from M32B1) and M35 (from M10A1) artillery prime movers; M7B1, M12, M40, and M43 self-propelled artillery; and the M10 Wolverine and M36 Jackson tank destroyers.