Saturday, December 24, 2016

Evolution of Tanks from 1918… Part II

The penchant for additional machine gun turrets was not confined to the British Army. The French 2C heavy tank already had a second machine gun turret at the rear of the hull and so did the 16 ton Grosstraktoren built secretly in Germany in 1929. The very first Japanese tank built in 1927 went further in having an additional machine gun turret at the front as well as the rear. The 19.5 ton Neubaufahrzeuge built in Germany in 1934 also had two machine gun turrets. But the provision of additional machine gun turrets was carried to an extreme in the A. 1 Independent heavy tank built in Britain in 1926 which had no fewer than four.

 The Vickers A1E1 in 1925

This aberration in tank design can be ascribed in part to the influence of naval ideas and the concept of the employment of tanks by themselves, which required them to ward off attacks from all quarters. In part it was also due to the contemporary tendency in Britain to overrate the effectiveness of machine guns and to ignore the need to arm tanks with guns of more than small calibre. This tendency was clearly demonstrated by the main armament of the 32 ton Independent which consisted only of a 47mm gun.

The other multi-turreted tanks, such as the Grosstraktoren and the Neubaufahrzeuge. did at least mount 75 mm guns in their main turrets. Multi-turreted tanks built in the Soviet Union were similarly armed with 76.2mm guns. They included the 17 ton T-2S first built in 1932. which had a machine gun turret on either side of the driver, like the British Sixteen-tonner. and the 45 ton T-32 and T-35, built in 1930 and 1933 respectively, which had five turrets like the Independent.

The 75 or 76.2mm guns mounted in German and Russian multi-turreted tanks were what the tanks of the period should have been armed with in general. Although they were short-barrelled, they fired projectiles which were effective against the armour of the contemporary tanks. At the same time they were of sufficiently large calibre to fire high explosive shells that were effective against various other targets. In consequence, tanks armed with them became what they basically are, namely a mobile source of fire power effective against virtually all battlefield targets. As versatile tank weapons they differed fundamentally from the 93.4mm mortars mounted in the close support versions of the Vickers Medium and other British tanks which were specialised weapons, intended primarily to fire smoke shells and never provided with armour-piercing ammunition.

In the meantime another category of tanks had come to the fore. It consisted of light tanks larger and heavier than those of the Vickers Carden Loyd pattern and armed not only with machine guns but also with 37 to 47mm guns. Unlike the lighter tanks they were capable, therefore, of fighting other contemporary tanks and they were also generally more effective tactically because they had two-man turrets.

Although they were lighter than the contemporary medium tanks but because they were armed with guns of the same calibre as some of the latter, tanks of this kind could be regarded as 'light-medium' rather than light tanks.

The BT, a 'light-medium', which was built in large numbers in the Soviet Union, was the most successful. The BT owed its origin to the outcome of several years' work in the United States by J W Christie on fast tanks which could run on wheels as well as tracks, an idea explored in several different forms during the 1920s. The most notable outcome of this work was an experimental vehicle built by Christie in 1928 which attained what was then a record speed of 68 km/h. A small number of T3 and T4 tanks was built from its basis between 1931 and 1936 for the U. S. Army, which did not however develop them any further. But in 1930 Christie sold two chassis to the Soviet Union, where they served as the basis for the design of the BT, which began to be produced by the end of 1931.

Of the major features which the BT inherited from Christie, the ability to run on the road wheels after the removal of the tracks proved of little value. But the BT very successfully followed Christie's ideas in having large, independently sprung road wheels and a high power-to-weight ratio. In 1933 the Russians added to this a 45mm gun and the BT became what was probably the most effective tank of the mid-1930s.

Six years after the Russians adopted Christie's ideas the British Army took note of what they had achieved with the BT and decided to use his type of suspension for British tanks. In the meantime, the A. 6 Sixteen Tonner and the Mark III Medium derived from it had been abandoned as too expensive and an attempt to produce a cheap medium tank with three turrets, the A. 9, did not prove a success. The next tank to be designed, in 1934, the A. 10 was much more sensible as it dispensed with the additional machine gun turrets. What is more, its original, A. 10 E. 1 version introduced what was to become many years later the standard configuration of tanks, with only the driver at the front, a three-man turret in the centre and the engine and transmission compartment at the rear of the hull. This configuration was then combined with a Christie-type suspension to produce in 1938 a new tank, the A. 13.

The A. 13 was somewhat larger than the BT but it was superior to it in having a three-man turret and short-pitch tracks, instead of Christie's noisy long-pitch tracks with which the Russians persevered. It also dispensed with Christie's idea that tanks should be able to run on their road wheels without tracks as well as with them, which was rightly adjudged in Britain to be an unjustified complication. Otherwise the general characteristics of the two tanks were similar, which included their weight of 13.8 to 14 tons. Thus A. 13 had the makings of a highly mobile, light-medium tank that could be used effectively in a number of roles. Unfortunately it was not regarded as such but as a more specialised 'cruiser' tank intended to be used in the cavalry role to which British armoured formations were being confined.

What is more, those in charge of British tank development still hankered after multi-turreted tanks and in 1938 placed orders for the A. 14 and A. 16 'heavy cruisers'. Each of these, once again, had two additional machine gun turrets but neither mounted in its main turret a gun larger than that of the A. 13. Development of the A. 14 and A. 16 was mercifully abandoned in 1939 but the tank which followed the A. 13 cruisers, the A. 15 or Cruiser Tank Mark VI, Crusader, still had one additional machine gun turret and the same 40mm gun as the A. 13.

Evolution of Tanks from 1918… Part I

When the First World War ended there were, broadly speaking, two categories of tanks. One consisted of tanks of 20 to 40 tons which were armed with guns of 57 to 75mm and which were intended for assaulting or breaking through enemy positions. The other category consisted of lighter tanks, which ranged in weight from 6.5 to almost 20 tons but which were armed only with machine guns or, at most, with 37mm guns. The great majority of them and in particular the Renault FT and its derivatives were intended for close infantry support.

Before the war ended much heavier tanks began to be developed in France and in Germany. In France this led to the 2C tanks of 68 tons, each of which was manned by a crew of 12 and was armed with a 75mm gun mounted, for the first time, in a turret. However, only ten of these tanks were completed, after the war In Germany construction began of two K-Wagen, which weighed about 150 tons and which were armed with four 77mm guns, mounted in sponsons. Each was to be manned by 22 men but both were destroyed after the war when they were about to be completed. The 2C tanks remained in service with the French Army until 1940, when they were destroyed without ever going into action but for two decades they were the heaviest tanks in use anywhere.

Nothing more was done about the development of tanks as heavy as this after the First World War when armies were generally concerned with much lighter vehicles. In particular, the French Army planned to develop a replacement for the Renault FT. But a successor to it. the Renault R-35 light tank, was not put into production until 1935. With a maximum speed of 20 km/h it was significantly faster and the maximum thickness of its armour was 40mm instead of 20mm. But the general concept of the two-man R-35 was much the same as that of its predecessor and its main armament consisted of the same short-barrelled 37mm gun as that mounted in the Renault FT. This showed a remarkable lack of concern about the most important characteristic of tanks, which is their armament, and made the R-35 virtually incapable of fighting other tanks.

Much more sensibly, the French Army also embarked on the development of a char de bataille armed with a 75mm gun, albeit mounted in the hull. But this was not put into production until 1934 in the form of the 27 ton Char B. I, which was quickly made obsolescent by the appearance of other, more recently developed tanks.

Better progress was made in Britain. It started with the recognition by the engineering staff of the Tank Corps that the speed of tanks could be increased by the use of sprung suspensions, which none of the British war-time tanks had, and by the use of higher powered engines. This led to the design of the 20 ton Medium D, which had a higher power-to-weight ratio than any previous tank and a maxi- mum speed of about 30 km/h, or more than twice the speed of any British or French tank built until then. But even this was improved upon by the 8 ton Light Infantry Tank derived from the Medium D which, on trials in 1922, attained a speed of 48 km/h. The two tanks represented therefore a considerable advance in mobility and they were also amphibious, at least to the extent of being able to swim across calm inland waters. But their design also incorporated a number of dubious features. These included a suspension consisting of a cable interconnecting all the road rollers on each side and a single spring, pivoted track plates in the case of the Medium D and laterally flexible tracks with spherical joints between the track plates in the case of the Light Infantry Tank. Moreover, both had fixed turrets and although some of the Medium D were to have a 57mm gun the rest were to be armed only with machine guns. What is more, the maximum thickness of their armour was only half that of the Renault FT. As fighting vehicles they therefore left much to be desired but it was mechanical troubles and financial stringency which led to a decision in 1922 to abandon them.

At the same time the British Army decided to order the second of two tanks designed by Vickers Ltd. as competitors to the Light Infantry Tank. This tank, which became known as the Vickers Medium, was not quite as fast as its competitor but it was capable of about 30 km/h, which put it well ahead of most contemporary tanks and enabled the Royal Tank Corps to take a lead in the development of more mobile methods of employing tanks. Its high speed was made possible by a properly sprung suspension and it was sensibly armed with a 47mm gun. What is more, in contrast to the one-man turrets of the tanks being developed in France, its turret accommodated a gunner and a commander who, being free of the task of firing the gun. could better exercise his craft. On the other hand, it suffered from the contemporary preoccupation with machine guns, having as many as six of them which could hardly be operated by its five-man crew. Also its armour was at first only 6mm thick. Nevertheless, in spite of its various shortcomings and the criticism levelled at it at different times, the Vickers Medium represented an important step forward in the development of tanks. It was also the only tank produced in quantity during the 1920s anywhere in the world, even though the total was not more than about 160 vehicles.

After the Vickers Medium entered service attention in Britain turned to much lighter vehicles. These were conceived, like the Renault FT, as small, light tanks for use with or by the infantry. But after a number of vehicles was tried between 1925 and 1927 it was decided that there was a need for two different light armoured vehicles: one was a machine gun carrier for the infantry and the other a reconnaissance tank, with a turret, for the armoured units.

Financial considerations, which made the relatively cheap light tanks so attractive to armies, did not inhibit them from going to the other extreme and trying to develop tanks that were large and expensive. In particular, the British Army planned to replace its Vickers Medium with a tank officially designated the A. 6 and commonly known as the Sixteen-tonner. This tank, which was designed by Vickers-Armstrongs in 1927, was a considerable advance on the Vickers Me- dium in having a better layout with a separated engine compartment at the rear of the hull and a three-man turret, and it was capable of up to 48 km/h. But at 14mm the maximum thickness of its armour was not greater than that of the contemporary light tanks and less than that of the Renault FT. What is more, its main armament consisted of a 47mm gun, which was virtually the same as the gun already used for several years in the Vickers Medium. The use of this gun was hardly compensated for by the addition of two small turrets, each with two machine guns, which were incorporated in the Sixteen-tonner at the express request of the Royal Tank Corps.

Tanks during and after the First World War

Although technology governed what could be done, its scope was sufficiently wide to provide a range of options in the design of tanks. In consequence, tanks came to vary considerably as these options were exercised to suit different ideas about their role or mode of employment.

The early ideas on the employment of British tanks were mainly those of Swinton who was made commander of the first British tank unit and who, in 1916, defined the tank as "primarily a machine gun destroyer, which can be employed as an auxiliary to an infantry assault". In other words, he regarded tanks as specialised vehicles which would help the infantry assault enemy trenches.

British tanks were, in fact, originally used as such. They were first sent into action, on the Somme, on 15 September 1916, when only 49 could be made available. Their first employment ignored Swinton's advice that they should be used by surprise and not in driblets and it met with relatively little success. It was only a year later, on 20 November 1917, at Cambrai, where 476 tanks were concentrated on a narrow front and used in a surprise assault over suitable ground, that tanks achieved a spectacular success in the role for which they were intended.

However, the battle of Cambrai also demonstrated that the capabilities of the original tanks did not extend beyond the short-range assault for which they were designed. To advance beyond it there had to be another, faster type of tank with a longer operating range which could exploit any breakthrough achieved by the other tanks. A lighter and faster tank, which became known as the Medium A, had already been designed and the first production model of it was completed shortly before the battle of Cambrai. But it was not used on any scale until the second major tank assault, at Amiens in August 1918, for which a total of about 600 tanks of all types was assembled.

Thus, by the end of the First World War in November 1918 the British Army had two categories of tanks. One consisted of the direct developments of the original tank, which culminated in the Anglo-American Mark VIII heavy tank. The other consisted of the Medium A and its successors. The role of the latter was about to be extended considerably as a result of experiments carried out by the engineering staff of the Tank Corps which showed that a tank could be built to have a maximum speed of 30 km/h, or more than twice the speed of any tank built until then. This inspired Colonel J F C Fuller, who was the chief of staff of the Tank Corps, to produce "Plan 1919", which proposed the use of fast medium tanks for raids against objectives well behind enemy lines. The raids were to be carried out by tanks called Medium D, which still had to be designed but work on which was started in 1918 by Lt. Colonel P Johnson. However, by the time a prototype of it was built the war was over.

Even before the infantry took over the French tank units, or the artillerie d'assaut as they were called until then, Colonel J E Estienne, who had become their commander, was already forecasting a very different way of employing tanks. Thus, in a study written in 1919, he foresaw the light accompanying tanks of the Renault FT type becoming after a time the organic equipment of the machine gun or heavy weapons companies of the infantry. They would then be succeeded by battle tanks which would be capable not only of destroying enemy machine guns but also enemy tanks. Companies of these tanks would replace infantry companies as the basic fighting units and future battles would be fought between tanks, whose armour and armament would need to be increased progressively. Other lighter and faster tanks might be useful for exploiting the success of the more powerful tanks, but Estienne very wisely commented that it would be a mistake to allow their construction to reduce the effectiveness or the number of the battle tanks, as the latter could never be too powerful or too numerous.

But Estienne's far-sighted views were ignored and, after several years of trying to improve the Renault FT, the French Army procured some more, albeit it more modern, infantry accompanying light tanks. The prime example of them was the Renault R-35, which became the most numerous French tank by 1940.

In the meantime more new ideas on the employment of tanks emerged in Britain and they led to its progress well beyond the confines of infantry support. To start with, in 1919, Fuller proposed that infantry battalions be reorganised to include a company of tanks. This foreshadowed the integrated tank-infantry battalions which were successfully created forty years later by the French and Swedish Armies but it could hardly be implemented at the time for lack of suitable tanks. Thus, the wartime British tanks were too clumsy to be incorporated within infantry battalions. A Light Infantry Tank was proposed but it still had to be designed and it was even faster than the Medium D, although Fuller considered that this did not make it incompatible with infantry marching on foot.

Fuller's proposal did not lead to any practical results but his writings and those of others promoted the formation, in 1927, of an Experimental Mechanized Force to explore some of the new ideas about a more mobile employment of tanks. The pursuit of these ideas was greatly helped, and to some extent inspired, by the Vickers Medium tanks with which the Royal Tank Corps was reequipped from 1923 onwards and which had a maximum speed of about 30 km/h - a speed considerably higher than that of all tanks used previously. In fact, a battalion of these tanks formed the core of the Experimental Mechanized Force. The latter also contained motorised infantry, artillery, reconnaissance and engineer units and thus constituted the first attempt at a self-contained force based on automotive vehicles. As such it provided some valuable experience but experiments with it led to two divergent lines of employment, neither of which made the most effective use of tanks.