Two Tanks In One

A story of what a Main Battle Tank is and how it came to be.

Tanks evolved considerably over the course of over 100 years of service. The first tanks were built to break through enemy fortifications, but still ended up being much smaller than the landships that H.G. Wells dreamed of. Nevertheless, the effect they had was considerable. All armies of the world wanted to have their own tanks, but not all managed to create one. A tank only seems simple, but in reality is quite a complicated fighting machine that requires a powerful industry to produce. Far fewer nations managed to build their own tanks than their own aircraft. In addition, like any weapon individual tanks quickly became obsolete. It is only in the last few decades that tank development slowed down from its breakneck pace. Tanks remain one of the key types of vehicles on the battlefield. There have been many attempts to write them off as a relic of the past, but practice shows that this time has not yet come.

T-72, the most numerous Main Battle Tank. These tanks were developed in the late 1960s but continue to serve and will do so for decades to come.

Initially tanks had no classification, they were just tanks. Light and medium tanks turned up later, and existing tanks were reclassified as heavies. The classes of tanks settled by the end of the First World War. Even though other classes such as tankettes or cavalry tanks (or rather armoured cars, since cavalry was not allowed to have tanks) turned up later, the trinity of light/medium/heavy tanks held on through the Second World War and even after. Heavy tanks died off, but nature abhors a vacuum. 

The first tanks were just tanks. Classification by weight only came around later.

The most common type of tank used today is not always correctly classified. This is the Main Battle Tank, a concept that appeared in the 1960s as a result of evolution of concepts from the late 1950s. These tanks replaced medium and heavy tanks in production, combining their best qualities. Let us discuss how these tanks came to be and why.

An attempt at creating a main tank was made in the 1920s. Medium tanks were not as slow and expensive as heavies, but also more effective than lights. It is no accident that British Medium Tanks Mk.I, Mk.II and Mk.III were their most numerous tanks of the 1920s, but they were ill-suited for the role of a main tank.

As mentioned above, the classification of tanks settled by the end of the First World War. The first heavy tanks were means of breaking through heavy enemy defenses. As practice showed, they had many drawbacks. Their armour quickly became insufficient and their mobility was too low. The light tanks first realized by the French had one main advantage: numbers. The Renault FT was not much more maneuverable than heavy tanks of the time and had considerably poorer firepower. It is not surprising that General Estienne, the main ideologue behind French tank building, became disillusioned in this tank. Next, the British came up with a medium tank. The Schneider CA 1 is often called a medium, but it just ended up in that weight class. The Medium Mark A was a completely different story. It was initially created for maneuver operations. The British were the first to see success with this type of vehicle. It is not surprising the Colonel John Fuller, the Chief of Staff of the Royal Tank Corps, placed his bet on medium tanks. At the same time, he did not abandon heavy breakthrough tanks. The end of the war made it more difficult to develop new types of armoured vehicles, but the first attempt to build a universal tank was nevertheless made in the interwar years.

Char B, the first attempt to create something close to a Main Battle Tank. General Estienne saw the Char B as the main tank on the battlefield, with the armour and armament of a heavy tank but mobility close to a contemporary medium tank.

Those who try to classify the Centurion, Panther, or T-62 as a Main Battle Tank must remember what an MBT actually is. The concept combines properties of heavy and medium tanks in one vehicle. None of the three aforementioned tanks aimed at replacing heavy tanks. Meanwhile, attempts to replace the heavy tank class were made in the 1920s. One can say that General Estienne was the father of the Main Battle Tank. His Char B was the first universal tank. Estienne expected that this tank would replace light and medium tanks. Heavy tanks were not mentioned, since France gave up on heavy tanks due to their cost. The result was a universal assault tank with a gun in the hull and machine guns in the cupola. It was only later that the Char B began to evolve and turned into a heavy tank by the time it was accepted into service. Initially, the tank was supposed to take the role that the Char D2 ended up filling.

The result of the "battle tank" program. Instead of a medium tank with the armour of a heavy, France ended up with a heavy tank with the armour and armament of a medium. The biggest problem was that the Char B1 bis was astronomically expensive and produced in tiny numbers, unable to replace medium tanks.

Further development is a whole different story, but the fact remains that the French were the first to develop the concept of a Main Battle Tank. This project was a failure, since the Char B1 bis ended up as a heavy tank and French command wanted light and medium tanks in addition to 20-ton "armoured cars" like the SOMUA S 35. Despite their efforts, the French settled in the classic light/medium/heavy categories like other armies in the world. However, most armies only managed to succeed in the light tank class or develop something on the cusp of two categories. For instance, the Soviet T-28 was developed as a medium maneuver tank, but ended up treated as a breakthrough tank. Light tanks made up the majority of every armoured force at the start of the Second World War and medium tanks only came to replace them after.

Despite conspiracy theories, the KV-13 tank that appeared in 1942 was developed as a heavy tank. No one was trying to replace the T-34.

Medium tanks were only used in force in May of 1940, after which it turned out that light tanks were no longer entirely suitable for the missions required of them. This took a while to sink in. A year later, the first wave of Soviet T-34 tanks was ground down relatively quickly and the tanks were only used en masse by the fall of 1941. Even though inexperience of Soviet tankers prevented them from using the tank to its full potential, the T-34 became a very big problem for the Germans. On the other side of the front line, medium tanks became the undisputed leaders in the Germany army by the start of Operation Barbarossa. The same thing happened in the American and British armies some time later. 

The Red Army was the first to obtain a truly mass produced heavy tank: the KV-1. However, the tank had a problem typical for vehicles of its class: overloading. This became clear in the winter of 1941-42 when the mobility of the KV-1 turned out to be significant lower than that of the T-34. An idea of lightening the tank was raised, leading to two projects: the KV-1S and KV-13. The latter is often called a "medium tank with heavy armour", which is incorrect. This was a heavy tank, but with the mass and mobility of a medium. It followed some of the concepts of a Main Battle Tank, but it was not an MBT. An MBT has to replace multiple classes of vehicles, and while the KV-13 was aiming to replace the KV-1, it was not a replacement for the T-34. The armament was also insufficient for a heavy tank at the time. The 76 mm ZIS-5 was no longer entirely satisfactory, but development of an 85 mm gun was impeded by various organizational and conceptional problems.

The Panther is sometimes classified as a heavy tank due to its weight, but it was a medium. The Panther was never a Main Battle Tank, since production of the Tiger continued in parallel.

The Panther was also never a Main Battle Tank. To start, the tank was never included in the TO&E of Heavy Tank Battalions. There were no plans to replace the Tiger with a lighter vehicle even in early 1945. The Panther was not a match for the role of an MBT even conceptually. One can often hear the claim that it had the armour and armament of a heavy tank. However, it's not that simple. Paradoxically, the Panther and Tiger are tanks from different generations. The Panther's contemporary heavy tank is the VK 45.02 (H), which later turned into the Tiger Ausf.B. The Panther's armour and armament were no match for this tank. There were attempts to increase the Panther's armour and firepower, but they were unsuccessful.

The Centurion is often classified as an MBT, but that is incorrect. It was intended to be a heavy cruiser tank, with its mass quickly growing from 40 to 50 tons. Its development did not stop work on heavy tanks.

Neither the concept nor the characteristics of the Panther tank match the requirements of a Main Battle Tank. This is an overgrown medium tank that grew fat enough to weigh as much as a heavy. There is no shortage of this phenomenon. The M26 Pershing is a classic example. The tank was created as a medium, but managed to spend some time classified as a heavy. It earned this designation purely due to its weight. The armour and armament were insufficient for this title, which is why there were numerous experiments to install thicker armour or a more powerful gun. These experiments ended with nothing, since the chassis did not have the capacity to carry the extra weight. The existence of the Pershing did not preclude the Americans from continuing work on heavy tanks. These tanks surpassed the Pershing both in armour and armament, meaning that the Pershing once again fails one of the main requirements for the role of a Main Battle Tank. The Centurion is in the same boat. The Cruiser Tank A41 was initially intended to replace the Cromwell. The tank's protection was also far from that of a heavy tank, as even the Centurion Mk.3 had scarcely more armour than a Panther.

Attempts to make a heavy tank from the Pershing ended badly every time. This was a medium tank that was pushed to its weight limit.

At the same time, one needs to quell fantasies regarding the IS-7. Its mass, armament, and armour are often compared to those of modern MBTs. It is quite silly to compare armour of modern tanks with those of the 1940s. Real life does not work like War Thunder or World of Tanks. The IS-7 was created to withstand fire from the 128 mm KwK 44 L/55 gun used on the Maus. Modern MBTs use 120-125 mm smoothbore guns firing either HEAT or long rod penetrators, in addition to ATGMs. The muzzle velocity of the 125 mm 2A46 gun is nearly twice as high as the muzzle velocity of WW2 era tank guns. Composite armour is required to resist weapons like these. Imagine what would happen to an IS-7 and its conventional steel armour. The armament is also in question. Even the M-65 gun created 10 years later has considerably better characteristics. The 130 mm S-70 certainly can deal considerable damage to a modern tank, but there are no illusions about how competitive it is. The mass of modern MBTs is also a necessary evil, if anything. For instance, the prototype of the Leopard 2 weighed 50.5 tons, the first production tank weighed 55 tons, and modern Leopard 2 tanks weigh 65 tons and continue to grow. This weight gain is not a desirable characteristic of the Main Battle Tank class, but a significant problem. As for the reputation of the IS-7 as a future-proof super tank, get ready to be disappointed. The military rejected the Object 260 since its weight exceeded the acceptable limit but its characteristics were still unsatisfactory. Prototype #3 that stands in Kubinka today was not even put to trial. A production IS-7 tank would have been very different.

This was the status of IS-7 trials in 1948. The tank was 3 tons heavier than expected and the cost of a pilot tank exceeded 3 million rubles.

Then there's the most important thing: production. One can't simply take a tank and put it into mass production. It would take effort to replace the T-54 with the IS-7, and no one was willing to expend this effort. The advantage of the Main Battle Tank is that it can be as numerous as a medium tank and not much more expensive. The number of heavy tanks could never compete with medium ones, but the price... a T-54 tank cost 588-635 thousand rubles in 1948 with the cost declining year over year. The IS-4 cost 795,000 rubles. The IS-7 would cost 3 million rubles even according to the most conservative estimates, and likely even more. The result was the a tank that looks pretty on paper, but has a number of design flaws, an outrageous price tag, and a number of unsolved issues such as transportation and evacuation. This is why the IS-7 was dropped and the 50 ton Object 730 was put into production. 

FV4201 or Chieftain, the first tank called a Main Battle Tank. It fully meets this classification: its armament and front armour matched that of contemporary heavy tanks, but mobility and weight matched those of medium tanks.

So who made the Main Battle Tank? The British did. This was a lengthy process and not one that gave fruit immediately. It became clear by 1946 that the Cruiser and Infantry divisions were pointless, and work began on the first universal tank. The FV201 was supposed to replace both Infantry and Cruiser tanks. The first attempt was not successful. The FV201 was marginal at best and the Centurion Mk.3 did not need replacing anyway. The FV201 evolved into the FV214 or Conqueror. The tank went into production in 1954, but the result was disappointing. The tank was too heavy and not exceptionally reliable. Meanwhile, the Centurion's star was starting to set. The chassis was becoming overloaded. As a result, the FV4201 was developed. This was the first tank to be designated a Main Battle Tank. The 45 ton tank was equipped with a 120 mm rifled gun, the mobility was expected to be no worse than a Centurion's, and the front armour was equivalent to a contemporary heavy tank. The project evolved into the 53 ton Chieftain, which was just 1-2 tons more than a Centurion Mk.10, but the armour was better, the armament was on par with heavy tanks, and the top speed was higher. The Main Battle Tank was born.

MBT 70, the German-American approach.

The USSR and USA approached the Main Battle Tank concept differently. Attempts to create a new generation of medium and heavy tanks continued into the late 1950s. The result was an unpleasant situation. The USSR found out about the American M60 tank with a 105 mm L7 gun. This was not a Main Battle Tank (the Americans cleverly dropped weight classifications in 1949, giving only the gun caliber) but it was still going to be a very problematic vehicle for the Soviet Army. Try as it might, it could not mass produce a heavy tank. There were no more than 200 T-10s built per year. This gave birth to the idea of a Main Battle Tank. This was not the T-62, which was a tank destroyer that complemented the missile-armed IT-1. The first true Soviet MBT was the Object 434 (T-64A) accepted into service with the Soviet Army on May 20th, 1968. This was a true Main Battle Tank and the first in a whole family of Soviet MBTs.

T-64A, the first Soviet MBT.

Some tanks like the Leopard 1 and AMX-30 were promoted into MBTs, but this is a stretch. The Leopard 1 and AMX-30 were medium tanks, with worse armour and armament than MBTs. The first German and American MBT was the MBT 70/Kpz.70, work on which began in 1963. This was their first tank to fully meet the requirements of an MBT. With a weight of 40 tons, it had powerful armour and armament. The result was something completely different, but 15 years later the results were obvious. The Leopard 2 and M1 Abrams are still in service and became trendsetters among Main Battle Tanks. The Soviet MBT concept also evolved to be an influential force. Both concepts have their advantages and drawbacks and continue to evolve.

Original article by Yuri Pasholok.