Cold War Main Battle Tanks I

During the Cold War the confrontation between NATO and Warsaw Pact tanks came to exemplify the land battle in a way that had no parallel at sea or in the air. Indeed, the tank became the dominant symbol by which armies not only were judged by others but also judged themselves; and when the Chieftain tank was described as the ‘virility symbol’ of the British army, the comment could equally well have been applied to other tanks and other armies.

THE REQUIREMENT

The main battle tank, like any piece of military equipment, was designed to meet a specification laid down in a general-staff requirement. The various armies had generally similar requirements, although, since the design of any weapons system must inevitably involve compromises, they tended to make different judgements on the relative priorities.

The requirement started with the tank’s offensive capabilities, which were that it had to be able to destroy the following:

• Tanks in daylight at an ever-increasing range. In the 1960s this was 2,000 m, but by the late 1970s it had increased to 3,000 m, and up to 5,000 m if possible, which had to be achievable with at least two different types of ammunition.

• Light armoured vehicles (e.g. armoured cars and armoured personnel carriers) at ranges out to 5,000 m, and troops in the open at all ranges between 75 m and 2,000 m.

• Field defences by direct fire using a high-explosive round (and also to fire smoke and illuminating rounds).

• Aircraft, particularly helicopters and drones, flying at low altitude (150 m) and low speed (maximum 300 km/h).

In order to perform these tasks the tank needed to be immune to enemy anti-tank weapons, using a combination of armour protection and the ability to present a small target by using ground, smoke and agility. Apart from protection against enemy anti-tank weapons, the crew also needed protection against nuclear, biological and chemical (NBC) weapons. The tank needed to have good cross-country mobility, coupled with long range to enable it to work over wide fronts and at great depths.

There was a host of other requirements, as well. For example, all nations required to move their tanks by train, which meant that the vehicle had to fit on to a standard flat wagon, and that its height and width must fit inside the relevant railways’ standard loading gauge. Similarly, weight was restricted by national road and bridge load-bearing capacities, as well as by the capability of tank-transporter vehicles. The designer’s task was to endeavour to meet as many of these requirements as possible, and, where they conflicted with each other, to achieve a compromise acceptable to the general staff.

TANK DEVELOPMENT 1949–1989

The story of the development of the tank is typical of that of many weapons systems during the years of the Cold War as NATO and the Warsaw Pact vied with each other in a seemingly endless competition, which cost their countries vast sums of money and kept some of their finest scientific brains and key defence industries fully employed.

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:

• Very-high-velocity solid projectiles fired by other tanks. These depended upon their kinetic energy to punch their way through the armour. and included the armour-piercing discarding sabot (APDS) and the armour-piercing fin-stabilized discarding sabot (APFSDS).

• High-explosive anti-tank (HEAT) projectiles, fired by enemy tanks or infantry. These used chemical energy to burn a hole through armour. Since the effect of these rounds did not depend on the velocity of the projectile, this type of warhead was used both in tank guns and in antitank guided missiles.

• High-explosive plastic (HEP) projectiles, fired by tanks. In these the round blistered on to the face of the armour plate and then exploded, dislodging a scab on the inner face which ricocheted around the inside of the tank.

• Anti-tank mines, which attacked the belly of the tank.

• Top-attack minelets, delivered by aircraft or artillery shells, which used small HEAT charges to attack the top of the tank.

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.

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. 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.

Next to appear was the T-62, which entered service in 1962 and was of generally similar shape and layout to the T-54/55, but slightly larger. It introduced the yet more powerful 115 mm gun (at a time when the West was standardizing on 105 mm), which was also the first smooth-bore tank gun to enter service, enabling it to fire fin-stabilized rounds with considerably greater muzzle velocity. The T-62 was, however, only a qualified success: among its serious shortcomings were a poor suspension, a tendency to shed its tracks, vibration, and an automatic cartridge-case ejection system which could severely injure its crews. These problems led to a much modified version, with a revised suspension, the T-72.

There then followed the T-64, a totally new design throughout, with a new 125 mm smooth-bore gun and a twenty-two-round automatic loader, which enabled the crew to be reduced to three men. The T-64B introduced a revised 125 mm gun, which was capable not only of firing normal rounds, but also of launching a radio-guided anti-tank missile with a range of up to 4,000 m. There was a new-style angular turret, which, together with the glacis (i.e. front) plate was fabricated from composite steel/fibreglass armour. The running gear, which gave good cross-country performance, was based on that of the JS-3, but, surprisingly in an army renowned for its simple, powerful and reliable engines, the power unit in the T-64 proved to be very unreliable. With horizontally opposed pistons, this was of similar layout to the British Chieftain tank engine, which also proved very troublesome. This led to the T-80, which was essentially an improved T-64 with a completely new gas-turbine power pack.

The T-72, which was produced in parallel with the T-64, had a different hull and suspension from the T-64, but mounted the same 125 mm smoothbore gun/missile launcher as in the T-64B. Later versions also included a laser rangefinder.

All these Soviet tanks were built in vast numbers and, as happened in other armies, they were constantly being upgraded and rebuilt. As new models appeared the older models were simply passed along the chain to lower-category units, thence to reserve units, and finally to storage depots, making it almost impossible to say that a Soviet tank had actually gone out of service.

Since their tanks were built to attack, and because much of western Europe’s terrain is criss-crossed by small rivers, the Soviets gave their tanks a river-crossing capability. This involved making the entire tank watertight and fitting a breathing tube to the turret hatch. Thus, if bridges were unavailable, Warsaw Pact tanks were able to wade across rivers up to 4.5 m deep, although the breathing tube was so narrow that there was no question of the crew using it for an escape, and river-crossing exercises were viewed with considerable trepidation by Warsaw Pact tank crews.

The Soviet army was consistently able to produce tanks which were at least 10 tonnes lighter than their Western counterparts. These tanks were built for a specific purpose – attacking in large numbers – and they suited that purpose well. Soviet designers were consistently innovative, producing new types of round and gun, and fielding devices such as automatic loaders at a time when Western designers were well short of perfecting them.

A major advantage for the Warsaw Pact was that its forces used only Soviet-designed tanks, which resulted in a great degree of standardization.

Although Soviet tanks were never used in anger against Western tanks in Europe, they did meet in wars in the Middle East and Asia. Generally speaking, in a one-on-one engagement the Western tanks proved superior in such wars – although not by a very wide margin. In the event of a conventional Warsaw Pact attack in western Europe the vastly greater numbers could well have been difficult to counter, especially as they would then have been operated by crews with much better training than those in the Middle East.

NATO TANKS

At one level NATO did manage to achieve a degree of standardization on tanks. Standardization agreements (known as STANAGS) were agreed through NATO channels and were published on many matters concerning tanks, a common main-gun calibre and the types of ammunition to be used, so that rounds could be freely exchanged between different armies. There were also a series of NATO Standard Tank Targets, based on the known criteria of Soviet tanks, which were the baseline against which all NATO guns were tested. These STANAGS were reasonably successful, although the agreements were not absolutely binding and countries were able to abandon them without penalty, apart from the logistic disadvantage of being unable to use standard NATO items.

At the highest level, however – that of tank design – NATO standardization was much less successful. Four NATO nations – France, Germany, the UK and the USA – designed tanks, and there were numerous attempts to achieve commonality through collaborative projects, but, without exception, these came to naught. The first was between France and Germany in 1956, when the plan was for the two countries to agree on the general specifications for a tank, following which they would each design and build prototypes. These would then be evaluated, and the resulting winner would be placed in production in both countries. The Germans had a domestic competition between two consortia, the winner of which was pitted against the sole French entrant, but the two countries could not agree on the outcome. As a result, the French placed their entrant in production as the AMX-30, while the Germans produced theirs as the Leopard 1. In a further divergence from standardization, while the West Germans armed their tank with the British 105 mm L7 gun– at that time the de facto NATO standard – the French armed the AMX-30 with their own 105 mm design, whose rounds could not be used in the L7 barrel.

Then, in 1963, the USA and West Germany agreed on a joint programme for a common tank to replace the American M60 and German Leopard 1 in the 1970s. The designers were given carte blanche to produce a totally new and revolutionary main battle tank (MBT), and this they certainly did. Known as the MBT-70, it included numerous innovative ideas, the most striking of which was a 152 mm gun/missile launcher, launching the Shillelagh missile, firing conventional ammunition with combustible cartridge cases, and served by a fully automated loader. The suspension was capable of ‘squatting’ to achieve a low profile in a static position, and could also be extended to ensure good cross-country mobility. There was a very powerful engine, capable of accepting numerous different fuels in line with NATO’s ‘multi-fuel’ policy. In addition, the automatic loader enabled the crew to be reduced to three, all of whom were housed in the turret, with the driver in an independently rotating capsule which ensured that he always faced forward. Sensors included a laser rangefinder and an environmental-control/life-support system, while reliability standards were supposedly the highest ever achieved in a tank.

A prototype was running in 1967, but by 1969 costs were escalating out of control. Estimated unit cost of a production MBT-70 was $1 million per tank at a time when the then current production tank, the M-60A1, cost $220,000 (both at 1970 prices). A design was prepared for an ‘austere’ version, designated XM-803, but the US Congress stopped the entire programme in January 1970, and it was accepted in both the USA and West Germany that virtually all the money spent on the MBT-70 programme had been wasted.

Similar British–German and Franco-German collaborative projects were equally unsuccessful, although they were both cancelled before the expenditure had reached MBT-70 proportions.

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