The German Tiger I tank was in use from late 1942 until the German surrender in 1945. It was given its "Tiger" nickname by Ferdinand Porsche (the roman numeral was added after the Tiger II was produced). The design served as the basis for other armoured vehicles, the Sturmtiger heavy self-propelled gun and the Bergetiger amoured recovery vehicle.
The Tiger differed from earlier German tanks principally in its design philosophy. Its predecessors balanced mobility, protection, and firepower. They were sometimes outgunned by their opponents, but greatly superior German tactics offset this disadvantage.
The Tiger I represented a new approach that emphasised firepower and armour at the expense of mobility. Design studies for a new heavy tank had been started in the late 1930s, without any production planning. The real impetus for the Tiger was provided by the quality of the Soviet T-34. Although the general design and layout were broadly similar to the previous medium tank, the Panzer IV, the Tiger weighed more than twice as much. This was due to its substantially thicker armour, the larger main gun, and the consequently greater volume of fuel and ammunition storage, larger engine, and more solidly-built transmission and suspension.
The Tiger I had frontal hull armour 100 mm thick and frontal turret armour of 110 mm, as opposed to the 80 mm frontal hull and 50 mm frontal turret armour of contemporary models of the Panzer IV. It also had 80 mm thick armour on the sides and rear. The top and bottom armour was 25 mm thick; later, the turret roof was thickened to 40 mm. Armour plates were mostly flat, with interlocking construction. The armour joints were of high quality, being stepped and welded rather than riveted.
The tank was too heavy for most bridges, so it was designed to ford four-metre deep water. This required unusual mechanisms for ventilation and cooling when underwater. At least 30 minutes of setup was required, with the turret and gun being locked in the forward position, and a large snorkel tube raised at the rear. Only the first 495 examples were fitted with this deep fording system, all later models were only capable of fording two metres.
The rear of the tank held an engine room flanked by two floodable rear compartments each containing a fuel tank, radiator, and fans. The petrol (gasoline) engine was a 21-litre 12-cylinder Maybach HL 210 P45 with 650 PS (641 hp, 478 kW). The engine drove front sprockets, which were mounted quite low.
The eleven-ton turret had a hydraulic motor powered by mechanical drive from the engine. A full rotation took about a minute. The suspension used sixteen torsion bars. To save space, the swing arms were leading on one side and trailing on the other. There were three road wheels on each arm, giving a good cross-country ride. The wheels had a diameter of 800 mm and were interleaved. Removing an inner wheel that had lost its tire (a common occurrence) required several outer wheels to be removed also. The wheels could become packed with mud or snow that could then freeze. Eventually a new 'steel' wheel design, with an internal tire was substituted.
The gun breech and firing mechanism were derived from the famous German "88" dual purpose flak gun. The 88 mm Kwk 36 L/56 gun was the variant chosen for the Tiger and was, along with the Tiger II's 88 mm Kwk 43 L/71, one of the most effective and feared tank guns of WW2. The Tiger's gun had a very flat trajectory and extremely accurate Zeiss TZF 9b sights. In British war-time firing trials, five successive hits were scored on a 16"x18" target at a range of 1,200 yards. Tigers were reported to have knocked out enemy tanks at ranges greater than a mile (1,600 m), although most WW2 engagements were fought at much closer range.
Another new feature was the hydraulically-controlled pre-selector gearbox and semi-automatic transmission. The extreme weight of the tank also meant a new steering system. Instead of the clutch-and-brake designs of lighter vehicles, a variation on the British Merritt-Brown single radius system was used. The Tiger's steering system was of twin radius type, meaning that two different, fixed radii of turn could be achieved at each gear, the smallest radius on the first gear was four metres. Since the vehicle had an eight-speed gearbox, it thus had sixteen different radii of turn. If a smaller radius was needed, the tank could be turned by using brakes. The steering system was easy to use and ahead of its time.
Although the Tiger I was one of the most heavily armed and armoured tanks of WWII, and a formidable opponent of Allied tanks, the design was conservative and had some serious drawbacks. The flat armour plates were unsophisticated in comparison to the sloped armour of the Soviet T-34, requiring a massive increase in weight to provide for sufficient protection. The tank's weight put severe stress on the suspension, whose complexity made maintenance difficult. The sophisticated transmission system was also prone to breakdowns.
A major problem with the Tiger was its very high production cost. During the Second World War over 40,000 American Sherman and 58,000 Soviet T-34s were produced, compared to 1,355 Tiger I and some 500 Tiger II tanks. The closest counterpart to the Tiger from the United States was the M26 Pershing (around 200 deployed during the war) and IS-2 from the USSR (about 3,800 built during the war).
