The Cold War: A MILITARY History (46 page)

All tanks are, in essence, compromises between mobility, firepower and protection, and the major armies came to differing conclusions about the balance, based primarily upon their experiences in the Second World War, but with some changes resulting from later conflicts such as the Korean and the Arab–Israeli wars. Thus the Soviet army, with its strategy of attack, was wedded to the concept of a fast, highly manoeuvrable tank with good firepower, which had also to be available in large numbers; protection and casualties were relatively low priorities in an army awash with manpower. The British, shaken by the way their tanks and in particular their guns had been outclassed by German tanks throughout most of the Second World War,
vowed
never to be outgunned again. Accordingly, they gave firepower the top priority, followed closely by protection, and with mobility a poor third; as a result, throughout the Cold War, British main battle tanks were almost invariably the heaviest in service. The Americans fell somewhere in between, their thrusting tactics requiring speed and manoeuvrability, with firepower second and protection third. All NATO countries, however, were convinced that the answer lay in defeating the sheer quantity of Soviet tanks by superior Western quality and sophistication.

Defeating the Opponent’s Tanks

There were four types of weapon for use against other tanks:

Two of the key criteria in the use of tank guns to fight other tanks were, first, their ‘first-round kill probability’ and, second, the achievement of ever greater range. These depended on a host of factors, each of which was repeatedly addressed during the course of the Cold War. The most effective rounds were those using kinetic energy to penetrate the enemy armour. The kinetic energy of a moving body is the product of the body’s mass multiplied by the square of its velocity, all divided by two:

Both variables in this equation were tackled with enthusiasm.

The rounds’ mass was increased by fabricating the rounds of ever denser material: first steel, then tungsten carbide and finally depleted uranium. Even greater attention was paid to increasing the velocity, since, as the equation above shows, the effect of this was squared. The original round was the armour-piercing discarding sabot, which was spin-stabilized, being ‘spun up’ by the rifling in the gun barrel; the mass could be increased by making the round longer, but beyond a length-to-diameter ratio of about 7:1 the round became inherently unstable. A length-to-diameter ratio of about 12:1 could, however, be obtained by making the round fin-stabilized, with almost negligible rotation. This resulted in a smooth-bore barrel, which was initially examined and rejected by the US army in the early 1950s, but which was adopted by the Soviets and the West Germans in the 1970s, even though it meant that none of the existing spin-stabilized range of ammunition could be fired and an entirely new range had to be produced.

The construction of the barrel and the methods by which it was produced were also critically re-examined, and new and more exotic production processes were developed to produce ever truer barrels. The question of increasing the accuracy of assessments of range to the target also exercised the tank designers, since, in a direct-fire engagement, the more precisely the range is known, the more likely it is that the first round will hit. In the early 1950s most tanks used an optical rangefinder, but the accuracy of such a device depends upon the length of its ‘base’ (i.e. the distance between the two lenses), which was limited by the width of the turret. A delicate optical device was also at an obvious disadvantage in a vehicle which travelled over rough terrain and which could expect to be hit by incoming rounds.

The British produced a simple system in which a machine-gun, mounted coaxially with the main gun and firing rounds which were ballistically matched to the APDS rounds, was used to find the range. This was accurate and cheap, but the intended target knew from the machine-gun hits that it was under attack and there was always a brief pause between the British tank gunner seeing the hit and firing the main gun. Finally came lasers, which were not only absolutely precise and gave an immediate read-out to the gunner, but were also difficult for the enemy tank to detect, although laser-warning devices started to be fitted in the 1980s.

As time went by, research revealed increasingly exotic factors which could affect the probability of a first-round hit. These included ambient weather conditions, since crosswinds could blow the round off course, while rain, temperature and humidity could also cause minor deviations. As a result, tanks were fitted with environmental sensors so that these factors could be included in the fire-control equation. Also, because the tank would be firing from a hastily chosen fire position, it was unlikely to be level, and so the
angles
relative to true vertical and true horizontal had to be calculated and allowed for.
^fn7

It was also discovered that, despite the ever more sophisticated methods of manufacture, barrels had become so long that they bent under their own weight. The amount of what was known as ‘droop’ was infinitesimal, but it was just enough to affect the gun’s accuracy. Thus a reflector was fitted in a protective housing above the muzzle and a laser in the turret detected the amount by which the barrel was off true. This too then became part of the fire-control calculations.

By this time the quantity of information being fed to the gunner was so large that he needed assistance from a fire-control computer. The complexity of the computer increased rapidly as its value was more fully appreciated – not least because it could perform a number of tasks automatically, thus easing the load on the tank gunner. One effect of the introduction of computers – usually known as ‘integrated fire-control systems’ (IFCS) – was to cause a rapid escalation in tank costs.

Defending One’s Own Tanks

The tank also had to be defended against enemy anti-tank weapons. In the 1940s and 1950s tank hulls and turrets were fabricated from cast homogenous steel, with the thickest armour in the forward quadrant, while protection against HEAT and HEP projectiles was obtained in some designs by spaced armour. As the kinetic-energy weapons became more powerful, tank designers responded by sloping the armour, thus effectively increasing the distance to be penetrated by the incoming round, as well as increasing the possibility that the round would ricochet off the plate. In the 1970s the British introduced ‘Chobham’ armour, which was created by mixing layers of conventional armour plate and ceramic materials, which effectively overcame the menace of the HEAT round.
^fn8
Then, in the 1980s, explosive reactive armour (ERA) appeared, in which the most vulnerable areas of the tank were covered with specially tailored explosive blocks, which were detonated when hit by an APDS/APFSDS projectile, thus diverting it away from the tank. The blocks were individually bolted to the armour plate and could be easily replaced. The Soviets also developed a special lining for the interior of their tanks, which was designed to prevent small metal fragments from ricocheting around the crew compartment.

These defences were all intended to defeat direct-fire weapons, but the anti-tank mine meant that the underneath of the tank had to be protected,
as
well. Such mines also attacked the tracks, damage to which could prevent the tank from moving, thus scoring a ‘mobility kill’.

Finally, the tops of the tank hull and turret were for many years more lightly armoured than the rest of the tank, because they were relatively safe from attack. In the 1980s, however, these areas also became targets for attack by a new weapon, the bomblet with a HEAT warhead, which was delivered in large numbers either by artillery shells or in canisters dropped by aircraft.

Tank Propulsion

At the start of the Cold War, Soviet tanks were all diesel-powered, while all Western tanks were powered by petrol engines. A petrol engine provided greater power for a given weight than a diesel, but fuel consumption was very high, resulting in a short range and a large load on the logistics system; the British Centurion Mk 3, for example, which served in the Korean War, had a range of just 161 km and had to tow a single-wheeled trailer to increase this. Also, petrol was inherently dangerous, with the US M4 Sherman being especially notorious for ‘brewing up’ when hit.

One of NATO’s earliest attempts at standardization was to insist that military engines should all be capable of ‘multi-fuel operation’, so that they could use petrol of varying grades and also diesel, with only minor adjustments required on changing over. This was tried and proved an expensive failure, and tank engines rapidly changed to diesels or turbo-charged diesels, which not only offered much greater range but also were markedly less flammable. In the 1980s, however, the US M1 Abrams entered service powered by a gas turbine, which offered exceptional power output for it size.

The ever-increasing power output from these engines tended to offset the growing weight, as is shown by the power-to-weight ratio, which is a fairly reliable means of assessing tank mobility. This increased from 10 kW/tonne for the British Chieftain in the 1970s to 19 kW/tonne for the US M1 and 20 kW/tonne for the German Leopard 2 in the 1980s.

SOVIET TANKS

Throughout the Cold War it was the Soviet tank force which held the initiative, with the West reacting to this. Soviet designers were innovative, while the Soviet General Staff appeared to be much less conservative about the design and employment of tanks than many of their counterparts in the West. There was also a fundamental difference in approach between the Soviet/Warsaw Pact and NATO armies, since the former were building tanks in very large numbers for an attack, whereas the latter built much fewer tanks for defence.

At the start of the Cold War, the Soviet armoured forces had tremendous
prestige
, having played a major role in the defeat of Nazi Germany. The main Soviet tank, the T-34, had come as a very unpleasant surprise to the Germans, having good armoured protection and being very robust, not too heavy (32 tonnes) and totally devoid of any frills. It was originally armed with a 76.2 mm gun, but was later upgunned with an 85 mm weapon, and in the early days of the Cold War this T-34/85 was considered to be a major threat to NATO’s Central Front.

The T-34/85 was complemented by the JS-3 (JS = Josef Stalin) heavy tank, which caused particular concern to Western armies in the early years of NATO, since it was armed with a 122 mm gun – by far the heaviest and most powerful weapon in any tank of that era, and able to defeat any NATO tank. In addition, the cast hull and turret were excellently shaped and made of armour up to 230 mm thick, which would have resisted any existing NATO tank gun. The JS-3 weighed 46 tonnes, had a maximum speed of 40 km/h, and, for its time, was a very formidable threat, and Western countries produced a number of tanks specifically to counter it. The JS-3 was produced in moderate numbers and was succeeded by the T-10, essentially an improved JS-3, but with even better armour, a newer and more powerful version of the 122 mm gun, and a new engine giving greater speed. The T-10 was in production from 1957 to the early 1960s, when it was phased out in favour of the T-62 medium tank, but, with the JS-3, it remained in service with reserve units for many years.

Meanwhile the major development effort was concentrated on the first post-war Soviet medium tank, the T-54, which entered service in 1954 and served with all the armies of the Warsaw Pact. Over 95,000 T-54s and an improved version, the T-55, were produced in the USSR, Czechoslovakia, Poland and China – a production run which lasted some thirty years, setting a record which is unlikely to be surpassed. The hull was well sloped, with thick armour, and the low, squat, hemispherical turret was designed to prevent penetration by anti-tank rounds, causing considerable discussion in the West. The T-54/55’s 100 mm gun was powerful for its time, and with their good cross-country performance and low profile these tanks were ideal for the Warsaw Pact requirements.