Tanks in WWII
Tanks played an important role in World War II. Invented by the British in World War I, the tank gradually improved in the inter-war period and also saw rapid changes in the Second World War. At one point a tank seemed to be state-of-the-art, then a year later it was obsolete.
doctrine changed radically during WWII. Previously, tanks had been used to
support infantry, but with the concept of Blitzkrieg, tanks became a formidable
branch of the army in its own right. Before the end of the war, tanks had
superseded infantry as the most important force on the battlefield.
(Picture below: Tiger II at the Deutsches Panzermuseum, Munster, Germany)
Although, Great Britain, the United States, Russia, France, Italy and Japan produced significant numbers of tanks before and during World War II, it is the German tanks like the panzer which are best known. The early tanks of Germany were technologically inferior to many of their opponent's tanks in the areas of armour and firepower, however it was in their tactical employment that German tanks dominated all rivals early in the war. German doctrine stressed the use of combined-arms involving mobile infantry and air support, and, after its surprising success during the execution of Fall Gelb (Battle of France), the tactic of the Blitzkrieg (lightning warfare) was developed. This doctrine required the Germans to equip their tanks with radios, which provided unmatched command and control. The Germans had worked extensively to develop tank mounted radio technology in order to replace the old systems of tank communication. Such as signal flares, messengers, and flags which had been used in world war I. the man who worked to spear head this development was col Heinz Guderian later to become General Guderian. In contrast, almost 80 percent of French tanks lacked radios, essentially because their battle doctrine was based on a more slow-paced, deliberate conformance to planned movements. This required fewer radios at all levels. French tanks generally outclassed German tanks in firepower and armour in the 1940 campaign, but their poor command and control doctrine made these advantages irrelevant to the final outcome.
Just as in World War I, there was experimentation with effective tank sizes. On the heavy side, the United States experimented with the T28 at 86 tonnes and Germany developed the 188-tonne Panzer VIII Maus, though neither entered service. The trend towards heavier tanks was unmistakable as the war proceeded. In 1939, most tanks had maximum armour of 30 mm or less, with guns no heavier than 37–47 mm. Medium tanks of 1939 weighed around 20 tonnes. By 1945, typical medium tanks had maximum armour over 60 mm thick, with guns in the 75–85 mm range and weights of 30 to 45 tonnes. Light tanks, which dominated most armies early in the war, gradually faded out and were mostly used in the reconnaissance role.
Turrets, which had always been considered, but were not previously a universal feature on tanks, were recognised as essential. It was appreciated that if the tank's gun was to be used to engage both 'soft' (unarmored) and armoured targets, then it needed to be as large and powerful as possible, making one large gun with an all-round field of fire vital. Also, mounting the gun in a turret ensured that the tank could fire from behind some cover. Hull-mounted guns on turreted tanks required that most of the vehicle be exposed to enemy fire. Multiple-turreted or multi-gun designs such as the Soviet T-35, American Medium Tank M3, French Char B or British A9 Cruiser Mk I slowly became less common during World War II. Un-turreted heavily armoured and armed vehicles (such as the Sturmgeschütz III) were used at longer ranges or against fortifications and were called tank destroyers or assault guns. It was recognized that a tank crew could not effectively control the fire of several weapons; also, newer dual-purpose guns eliminated the need for multiple weapons. Most tanks still retained a hull machine gun, and usually one or more machineguns in the turret, to protect them from infantry at short range.
During the Second World War, tanks usually began to be equipped with radios, vastly improving their command and control. By 1943, two-way radio was nearly universal. Tanks were adapted to a wide range of military jobs, including mine clearance and engineering tasks. Specialized models, such as flame-thrower tanks, recovery tanks for towing disabled tanks, and command tanks with extra radios and dummy turrets were also used. Some of these tank variants live on as other classes of armoured fighting vehicle, no longer called "tanks". All major combatant powers also developed tank destroyers and assault guns - armoured vehicles carrying large calibre guns, but often no turrets. Turreted vehicles are expensive to manufacture compared to nonturreted vehicles. One trend seen in World War II was the usage of older, lighter tank chassis to mount larger weapons in fixed casemates as tank destroyers or assault guns. For example, the Soviet T-34 could mount an 85 mm gun in the turret, but the same chassis could carry the much more effective 100 mm gun in a fixed casemate as the SU-100. Likewise, the obsolete German Panzer II light tank was modified to take a powerful 75 mm PAK-40 gun in an open-topped, fixed casement as the Marder II.
(Picture below: Japanese Type 97 Shinhoto Chi-Ha on display at the US Army Ordnance Museum in Aberdeen)
While some of the Italian tanks ("Carro Armato") were fairly modern in 1939, by the early part of Italy's war they had become completely obsolete. The better armed and armoured P 40 heavy tank never entered service with the Italian army, although a few were taken over by the Germans.
Japan used tanks during the invasion of China before World War II as well as during the Far Eastern campaigns from 1941. As China and the Allies had few armored forces available at that time the Japanese vehicles were quite adequate, the more so as their primary role was infantry fire support rather than tank-against-tank operations. Once the tide turned against Japan, however, these same armoured vehicles proved distressingly vulnerable to superior Allied tanks such as the M4 Sherman, and were largely relegated to use as dug-in pillboxes or static artillery.
From Wikipedia (http://en.wikipedia.org/wiki/Tanks_in_World_War_II)