AMX 50
Encyclopedia
The AMX 50 or AMX-50 was a French heavy tank
designed in the immediate post Second World War
period. It was proposed as, in succession, the French medium
, heavy and main battle tank
and incorporated many advanced features. However it was to suffer cancellation in the late fifties due to unfavourable economic and political circumstances combined with delays in development.
was being developed, but this vehicle, though to be armed with a powerful 90 mm gun, could hardly be called modern, as its suspension system was obsolete. Therefore already in March 1945 the French industry had been invited to design a more satisfactory vehicle. The same year the AMX company (Atelier de Construction d'Issy-les-Moulineaux) presented its projet 141, a project to build the so-called M 4 prototype, armed with a 90 mm Schneider gun.
The M 4 closely resembled the German King Tiger in general form, though the turret was to be made of welded sections; but to limit the weight to a desired thirty metric tonnes the proportions were rather smaller and the armour had a maximum of just thirty millimetres. Like the later German tanks of the war it had, in this case eight, overlapping road wheels. Part of the project was to study whether a modern torsion bar suspension should be used or the height lowered by ten centimetres through a fitting of leaf or coil springs.
Two prototypes of the M 4 were ordered. The Army soon indicated that a protection level of thirty millimetres was unacceptably low. In response armour was increased. To save weight it was decided to install a novel oscillating turret
, designed by FAMH. Nevertheless, when the first prototype, now named the AMX 50 after its intended weight class, was delivered in 1949, it weighed 53.7 metric tonnes. In the winter of 1950 instead of the 90 mm, a 100 mm gun was fitted, designed by the Arsenal de Tarbes. The second prototype with a slightly different turret, but also with a 100 mm gun, was ready soon after. The prototypes had a length, with gun, of 10.43, a width of 3.40 and a height of 3.41 metres. It was intended to fit a 1200 hp engine to attain a speed much superior to all existing medium tank types. The Maybach HL 295 (a redesigned German gas engine in 1945 captured at Friedrichshafen
by Engineer-General Joseph Molinié) and a Saurer diesel engine were tested. Both failed to deliver the required output and maximum speed was in fact no higher than 51 km/h. The prototypes were tested between 1950 and 1952.
Parallel to the tank, AMX from 1946 designed the AMX Chasseur de Char, a lightly armoured 34 tonne tank destroyer
based on the M 4 chassis, but fitted with a modern rounded sleek turret for the 90 mm gun. No prototype was built.
company also developed a tank to meet the demand for a heavily armed vehicle: the Char SOMUA SM, that however had been conceived as a heavy tank, Char Lourd, in the sixty tonne weight class, from the very beginning, again imitating the German King Tiger. The order to build a prototype was given in 1946, the vehicle was delivered in October 1951, weighing 56 metric tonnes. Both companies had in the end been forced by the Army to work along identical and detailed specifications. As a result the SOMUA SM closely resembled the AMX 50: it too had an oscillating turret, first with a 90 mm, then with a 100 mm gun. The main external difference was that the nine road wheels were not overlapping. It only was tested between January and July 1953 as many parts had not been sufficiently developed; the delay ensured that the type was rejected.
Based on the M 4 chassis in 1950 a prototype was finished of a heavy tank destroyer in the form of a 120 mm self-propelled gun
, the Canon Automoteur AMX 50 Foch, named after Marshal Ferdinand Foch
. It was intended to give long range fire support to the medium AMX 50 "100 mm"; after the tank version itself was planned to be armed with a 120 mm gun, the Foch project was abandoned.
The tank project was based on a 1950 self-propelled gun design by Lorraine, originally intended to be armed with a 90 mm gun, the Canon d'Assaut Lorraine. The prototype of this tank destroyer was finished in 1952, fitted with a 100 mm gun and weighing 25 metric tonnes. The project was discontinued in 1953.
designs of the postwar period (the others being the AMX-13
and the Panhard EBR
) to feature an oscillating turret
. The oscillating turret design, lacking a conventional gun-mantlet
, is in two separate parts, with an upper and lower part connected by two hinge bolts or pivots, the gun
being fixed within the upper section. The horizontal movement of the gun, traversing, is conventional, but the vertical movement, elevation
, is achieved through the pivoting of the entire upper section with respect to the lower section. This method of elevation has two main advantages. Firstly it allows for a smaller turret volume, as no internal space is needed for the vertical movement of the gun breech. Secondly, it allows the use of a relatively simple auto-loader fed by multiround magazines, achieving a very high rate of fire for as long as the magazines were loaded, as the gun is also fixed with respect to the auto-loader located in the back of the upper turret, i.c. a protruding bustle. The automatic loading system worked satisfactorily when the calibre was 100 mm. After the larger 120 mm gun was introduced, reliability suffered, due to the increased weight of the rounds used. The oscillating turret was a very fashionable concept in the fifties, and also applied in some American projects, such as the T57 and T58. Only the French however, would produce operational systems.
The hull was equipped with a torsion bar suspension designed to ensure a vehicle with good cross-country mobility. The hull and suspension recalled both the German Tiger
and the Panther tank
s which, having entered French service after the war, were well known and deliberately imitated. Especially the engine deck, the sprockets and the tracks are strongly reminiscent of the German design style. The nine overlapping tyred road wheels each side, were however much smaller. The French engineers had not been aware at first that the much admired German overlapping design had been motivated by a shortage of high quality rubber, necessitating large road wheels to lower tyre tension, which then were made overlapping to better distribute the load pressure. As France would have no trouble obtaining rubber of the desired quality, this feature was superfluous. Therefore the road wheels were made smaller, compared to the first design proposal, both to save weight and lower the profile of the tank, which was quite high due to a deep hull, a problem only changed in the fifth prototype. The track now had to be supported by five top rollers. The overlapping system as such was maintained in all prototypes; with smaller wheels it allowed for nine instead of the originally planned eight wheels, five forming the outer, four the inner row.
The engine
and transmission
system was in the rear of the vehicle with rear drive sprockets
. The transmission was derived from the ZF of the Panther. The functions of final drive and steering were combined in a single assembly; for each gear two turning radii could be selected. The engine was the Maybach HL295 12 cylinder of 29.5 litres, using fuel injection combined with spark ignition. The project goal was to bring the engine output to 1200 hp, implying a very favourable hp/litre ratio of over forty. This proved to be unrealistically ambitious, given the level of technological development at the time; in reality not even a ratio of thirty was reliably attained.
The hull sides were vertical, as in the case of the Tiger, while the front of the hull was in the first three prototypes evenly inclined at approximately 40 degrees from the horizontal, using sloped armour
similar to that of the Panther and Tiger II. The corners between the glacis and the sides were truncated. The first two prototypes had a frontal protection level equivalent to about 120 mm "line-of-sight" thickness in the horizontal plane. The type was thus not particularly heavily armoured for its time. The weight increase with the third prototype was mainly caused by the larger turret and even in its fourth "uparmoured" form, doubling the frontal armour thickness, the AMX 50 was less well protected than its American and British competitors, themselves inferior in armour to the Soviet heavy tanks they had been created to fight. The fifth prototype used a lower cast hull, with a rounded frontal section for a better weight efficiency.
Above the massive hull, there was the oscillating turret
, smaller, lighter and more compact than that of the Tiger; the sloped face of the upper part had a thickness of 85 mm. In the turret rear back there was the commander's cupola, well equipped with optical equipment. The turret had an optical rangefinder. The first two prototypes had twin 7.5 mm "Reibel" machine gun
s placed on top of the roof as an AA-weapon, a third was coaxial. In the first design proposal for a 120 mm version, the conventional turret had a high cupola armed with both a machine gun and a 20 mm MG 151 rapid fire cannon. However the third and fourth "120 mm" oscillating turret prototypes had a single 7.5 mm AA machine gun and a second 7.5 mm coaxial machine gun. For the production vehicles it was considered to install a coaxial 20 mm gun; lighter armoured targets could then be engaged without depleting the limited ammunition stock in the turret magazines. Despite the auto-loader, the crew was four: a second man was seated in the hull, functioning as radio-operator, but mainly needed to replenish the turret magazines from the hull ammunition stocks.
, the firepower of the Tiger
, the mobility and abundance of the T-34
, the reliability of the M4 Sherman
and all that weighing less than the M26 Pershing
. At that time France hoped to regain its position as a Great Power; rebuilding its armaments industry served this goal. To build an indigenous battle tank was however not merely a question of national prestige. Europe as a whole was trying to recover from the devastations caused by the war and to assert a modicum of independence towards the two superpowers, the USA and the USSR. To this end in 1948 the Treaty of Brussels
was signed, which among other things was also a common defence agreement. The AMX 50, superior in armament and mobility to the existing American and British designs, was seen as the logical candidate for a common European tank, to equip the future armies of the Western European Union
defence organisation. The prototypes were proudly displayed during the 1950 Bastille Day
parade. Somewhat inconsequentially, it was hoped that the Americans would fund such a tank, as the financial position of the European states would not allow them to rearm.
That same year, the situation changed drastically due to the outbreak of the Korean War
. Quickly the USA recommenced medium tank mass production, of the new M47 Patton
. When this tank proved to be unsatisfactory, an even more advanced type was taken into production for the American forces, the M48 Patton
; thousands of M47s were leased for free to the European allies, France included. The AMX 50 was suddenly made redundant as a medium tank, despite a "100 mm" prototype being sent in 1952 to the Aberdeen Proving Grounds for, successful, tests.
To save the project, a new rôle was found in the Soviet heavy tank threat. In the early fifties, NATO tacticians were worried by the strong armour of the Soviet vehicles, that seemed to be immune to the guns of the existing Western types. In response Britain would develop the Conqueror
and the USA the M103 heavy tank
; abandoning the SOMUA SM, it was decided to let the AMX 50 evolve into a comparable type, even though other French heavy tank projects were in existence, such as the Char de 70 tonnes, a sort of "AMX 70". Already having a large chassis, the AMX 50 could in principle easily be adapted to carry the desired 120 mm gun — a derivation by the Atelier du Havre of the American gun, using the same ammunition — and had the advantage of a, on paper, very powerful engine. In practice there were many obstacles. Room could in fact only be found by increasing the height of the lower turret half, negating the advantages of the oscillating concept and creating a dangerous shot trap. The "uparmoured" version, with its deeper hull and flatter turret, was specially designed to counter this and make the vehicle immune in long range fire engagements, but further increased weight. In 1955 the AMX 50 was nevertheless very close to being ordered by the French government, that expected to produce the type for the reconstituted German Army also. A production was planned of a hundred for 1956. This decision had to be delayed however, due to the fact the engine problems had not been solved: reliability could only be assured if the output was limited to 850 hp, causing a mediocre hp/tonne ratio of about 13:1.
The delay proved fatal to the project. In the late fifties, swift advances in hollow charge technology led to an increased vulnerability for heavy tanks. Mobility thus gained a priority over protection and the very concept of a heavy tank became obsolete. As a result the project was changed again in intention, now trying to present itself as an agile main battle tank, with the same gun as the Conqueror but much lighter and more powerful. This failed as it was much too large and expensive; oscillating turrets also became unpopular as they were inherently difficult to protect against nuclear and chemical contamination. The engine problems with the Maybach were never overcome and lowering the hull to save weight, as was done for the final prototype, made it impossible to install a larger engine. Recognizing that the problem of combining excellent mobility with heavy armour was for the time being irresolvable, the AMX 50 project was terminated; the priority given to mobility demanded a new design concept, leading to the AMX 30, the lightest MBT of its time. Only in the early eighties would France again attempt to combine heavy armour and armament in its tank designs, beginning with the later AMX 32 prototypes. The AMX 50 would not be a complete waste of time and effort however, as much technological knowledge had been gained from which the AMX 30 would profit.
In the Musée des Blindés
at Saumur
an AMX 50 is shown, a combination of the last cast hull and the Tourelle D.
Heavy tank
A heavy tank was a subset of tank that filled the heavy direct-fire role of many armies.Heavy tanks have usually been deployed to breakthrough enemy lines, though in practice have been more useful in the defensive role than in the attack...
designed in the immediate post Second World War
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
period. It was proposed as, in succession, the French medium
Medium tank
Medium tank was a classification of tanks; the medium being intermediate in size and weight and armament between heavy tanks and light tanks.The medium tank concept has been eclipsed by the main battle tank.-History:...
, heavy and main battle tank
Main battle tank
A main battle tank , also known as a battle tank or universal tank, is a tank that fills the heavy direct fire role of many modern armies. They were originally conceived to replace the light, medium, heavy and super-heavy tanks. Development was spurred onwards in the Cold War with the development...
and incorporated many advanced features. However it was to suffer cancellation in the late fifties due to unfavourable economic and political circumstances combined with delays in development.
M 4
After the war the French Army possessed no modern tanks with a heavy armament. The ARL 44ARL 44
The ARL 44 was a French heavy tank produced just after World War II. Only sixty of these tanks were ever manufactured and the type was quickly phased out.-Development:...
was being developed, but this vehicle, though to be armed with a powerful 90 mm gun, could hardly be called modern, as its suspension system was obsolete. Therefore already in March 1945 the French industry had been invited to design a more satisfactory vehicle. The same year the AMX company (Atelier de Construction d'Issy-les-Moulineaux) presented its projet 141, a project to build the so-called M 4 prototype, armed with a 90 mm Schneider gun.
The M 4 closely resembled the German King Tiger in general form, though the turret was to be made of welded sections; but to limit the weight to a desired thirty metric tonnes the proportions were rather smaller and the armour had a maximum of just thirty millimetres. Like the later German tanks of the war it had, in this case eight, overlapping road wheels. Part of the project was to study whether a modern torsion bar suspension should be used or the height lowered by ten centimetres through a fitting of leaf or coil springs.
Two prototypes of the M 4 were ordered. The Army soon indicated that a protection level of thirty millimetres was unacceptably low. In response armour was increased. To save weight it was decided to install a novel oscillating turret
Oscillating turret
An oscillating turret is a form of turret for armoured fighting vehicles, both tanks and armoured cars. The turret is unusual in being made of two hinged parts. Both elevation and recoil rely on the upper part of the turret moving relative to the lower part....
, designed by FAMH. Nevertheless, when the first prototype, now named the AMX 50 after its intended weight class, was delivered in 1949, it weighed 53.7 metric tonnes. In the winter of 1950 instead of the 90 mm, a 100 mm gun was fitted, designed by the Arsenal de Tarbes. The second prototype with a slightly different turret, but also with a 100 mm gun, was ready soon after. The prototypes had a length, with gun, of 10.43, a width of 3.40 and a height of 3.41 metres. It was intended to fit a 1200 hp engine to attain a speed much superior to all existing medium tank types. The Maybach HL 295 (a redesigned German gas engine in 1945 captured at Friedrichshafen
Friedrichshafen
This article is about a German town. For the Danish town, see Frederikshavn, and for the Finnish town, see Fredrikshamn .Friedrichshafen is a university city on the northern side of Lake Constance in Southern Germany, near the borders with Switzerland and Austria.It is the district capital of the...
by Engineer-General Joseph Molinié) and a Saurer diesel engine were tested. Both failed to deliver the required output and maximum speed was in fact no higher than 51 km/h. The prototypes were tested between 1950 and 1952.
Parallel to the tank, AMX from 1946 designed the AMX Chasseur de Char, a lightly armoured 34 tonne tank destroyer
Tank destroyer
A tank destroyer is a type of armored fighting vehicle armed with a gun or missile launcher, and is designed specifically to engage enemy armored vehicles...
based on the M 4 chassis, but fitted with a modern rounded sleek turret for the 90 mm gun. No prototype was built.
SOMUA SM
In competition with AMX, the SOMUASomua
Somua, an acronym for Société d'outillage mécanique et d'usinage d'artillerie, was a French company that manufactured machinery and vehicles. A subsidiary of Schneider, Somua was based in Saint-Ouen....
company also developed a tank to meet the demand for a heavily armed vehicle: the Char SOMUA SM, that however had been conceived as a heavy tank, Char Lourd, in the sixty tonne weight class, from the very beginning, again imitating the German King Tiger. The order to build a prototype was given in 1946, the vehicle was delivered in October 1951, weighing 56 metric tonnes. Both companies had in the end been forced by the Army to work along identical and detailed specifications. As a result the SOMUA SM closely resembled the AMX 50: it too had an oscillating turret, first with a 90 mm, then with a 100 mm gun. The main external difference was that the nine road wheels were not overlapping. It only was tested between January and July 1953 as many parts had not been sufficiently developed; the delay ensured that the type was rejected.
AMX 50 "120 mm"
A third AMX 50 project was begun in August 1951. Ten preseries vehicles were to be built by DEFA (Direction des Études et Fabrications d'Armement, the state weapon design bureau), the first being delivered in 1953. The type was armed with a 120 mm gun in response to the perceived threat posed by the Soviet heavy tanks, such as the IS-3 and the T-10. To accommodate the larger gun, an enormous turret was fitted; originally planned in a conventional form, eventually it was decided to make it of the oscillating type also. Armour was increased. These changes caused a weight increase to 59.2 metric tonnes. From 1954 to 1955 this type was made even heavier, creating the surblindé version ("AMX 50 Uparmoured") with a lower turret and a higher hull with a pointed glacis like the IS-3, bringing weight to about 64 tonnes. As this caused serious mechanical reliability concerns despite a reinforced suspension, from 1956 to 1958 weight was diminished to 57.8 metric tonnes by building a lower cast hull, creating the surbaissé ("AMX 50 Lowered") with a lighter but again higher turret, the Tourelle D (fourth type turret). As problems with the preferred Maybach persisted, despite limiting the desired output to 1000 hp, from 1955 a special design team (Gruppe M) brought over from Germany cooperated with the AMX factory to solve them. Optimistically it was at that time projected that maximum speed could eventually be increased to 65 km/h. In the end in total only five complete AMX 50 prototypes would be constructed, including the final hull.Based on the M 4 chassis in 1950 a prototype was finished of a heavy tank destroyer in the form of a 120 mm self-propelled gun
Self-propelled gun
A self-propelled gun is form of self-propelled artillery, and in modern use is usually used to refer to artillery pieces such as howitzers....
, the Canon Automoteur AMX 50 Foch, named after Marshal Ferdinand Foch
Ferdinand Foch
Ferdinand Foch , GCB, OM, DSO was a French soldier, war hero, military theorist, and writer credited with possessing "the most original and subtle mind in the French army" in the early 20th century. He served as general in the French army during World War I and was made Marshal of France in its...
. It was intended to give long range fire support to the medium AMX 50 "100 mm"; after the tank version itself was planned to be armed with a 120 mm gun, the Foch project was abandoned.
Char Lorraine
As it was already obvious in the early fifties that the AMX 50 might well turn out to be too heavy — the eventual weight of 53.7 tonnes came as a shock — a parallel medium tank project was initiated in 1952. A prototype was built by the Lorraine factory. It too had an oscillating turret, with a 100 mm SA 47 gun, but hull mass was diminished by fitting a light-weight suspension using five road wheels with inflated rubber tyres. Total weight was thus limited to 39.7 metric tonnes. The length was 10.80 metres, width 3.30 metres and height 2.85 metres. Its maximum speed was 60 km/h. It had a crew of four.The tank project was based on a 1950 self-propelled gun design by Lorraine, originally intended to be armed with a 90 mm gun, the Canon d'Assaut Lorraine. The prototype of this tank destroyer was finished in 1952, fitted with a 100 mm gun and weighing 25 metric tonnes. The project was discontinued in 1953.
Description
Because there were five prototypes, it is not possible to give a description applying to all of them in detail. Weighing about fifty-five tons, the general AMX 50 project was the heaviest of a trio of French AFVArmoured fighting vehicle
An armoured fighting vehicle is a combat vehicle, protected by strong armour and armed with weapons. AFVs can be wheeled or tracked....
designs of the postwar period (the others being the AMX-13
AMX-13
The AMX-13 is a French light tank produced from 1953 to 1985. It served with the French Army and was exported to over twenty-five other nations...
and the Panhard EBR
Panhard EBR
The Panhard EBR is a light armoured car designed by Panhard for the French Army and later used across the globe, notably by the French Army during the Algerian War and the Portuguese Army during the Portuguese Colonial War in Angola, Mozambique and Guinea-Bissau.The EBR is an 8x8 wheeled...
) to feature an oscillating turret
Oscillating turret
An oscillating turret is a form of turret for armoured fighting vehicles, both tanks and armoured cars. The turret is unusual in being made of two hinged parts. Both elevation and recoil rely on the upper part of the turret moving relative to the lower part....
. The oscillating turret design, lacking a conventional gun-mantlet
Gun mantlet
A gun mantlet is an armour plate or shield attached to an armoured fighting vehicle's gun, protecting the opening through which the weapon's barrel projects from the hull or turret armour and, in many cases, ensuring the vulnerable warhead of a loaded shell does not protrude past the vehicle's...
, is in two separate parts, with an upper and lower part connected by two hinge bolts or pivots, the gun
Gun
A gun is a muzzle or breech-loaded projectile-firing weapon. There are various definitions depending on the nation and branch of service. A "gun" may be distinguished from other firearms in being a crew-served weapon such as a howitzer or mortar, as opposed to a small arm like a rifle or pistol,...
being fixed within the upper section. The horizontal movement of the gun, traversing, is conventional, but the vertical movement, elevation
Elevation (ballistics)
In ballistics, the elevation is the angle between the horizontal plane and the direction of the barrel of a gun, mortar or heavy artillery. Originally, elevation was a linear measure of how high the gunners had to physically lift the muzzle of a gun up from the gun carriage to hit targets at a...
, is achieved through the pivoting of the entire upper section with respect to the lower section. This method of elevation has two main advantages. Firstly it allows for a smaller turret volume, as no internal space is needed for the vertical movement of the gun breech. Secondly, it allows the use of a relatively simple auto-loader fed by multiround magazines, achieving a very high rate of fire for as long as the magazines were loaded, as the gun is also fixed with respect to the auto-loader located in the back of the upper turret, i.c. a protruding bustle. The automatic loading system worked satisfactorily when the calibre was 100 mm. After the larger 120 mm gun was introduced, reliability suffered, due to the increased weight of the rounds used. The oscillating turret was a very fashionable concept in the fifties, and also applied in some American projects, such as the T57 and T58. Only the French however, would produce operational systems.
The hull was equipped with a torsion bar suspension designed to ensure a vehicle with good cross-country mobility. The hull and suspension recalled both the German Tiger
Tiger I
Tiger I is the common name of a German heavy tank developed in 1942 and used in World War II. The final official German designation was Panzerkampfwagen Tiger Ausf. E, often shortened to Tiger. It was an answer to the unexpectedly formidable Soviet armour encountered in the initial months of...
and the Panther tank
Panther tank
Panther is the common name of a medium tank fielded by Nazi Germany in World War II that served from mid-1943 to the end of the European war in 1945. It was intended as a counter to the T-34, and to replace the Panzer III and Panzer IV; while never replacing the latter, it served alongside it as...
s which, having entered French service after the war, were well known and deliberately imitated. Especially the engine deck, the sprockets and the tracks are strongly reminiscent of the German design style. The nine overlapping tyred road wheels each side, were however much smaller. The French engineers had not been aware at first that the much admired German overlapping design had been motivated by a shortage of high quality rubber, necessitating large road wheels to lower tyre tension, which then were made overlapping to better distribute the load pressure. As France would have no trouble obtaining rubber of the desired quality, this feature was superfluous. Therefore the road wheels were made smaller, compared to the first design proposal, both to save weight and lower the profile of the tank, which was quite high due to a deep hull, a problem only changed in the fifth prototype. The track now had to be supported by five top rollers. The overlapping system as such was maintained in all prototypes; with smaller wheels it allowed for nine instead of the originally planned eight wheels, five forming the outer, four the inner row.
The engine
Engine
An engine or motor is a machine designed to convert energy into useful mechanical motion. Heat engines, including internal combustion engines and external combustion engines burn a fuel to create heat which is then used to create motion...
and transmission
Transmission (mechanics)
A machine consists of a power source and a power transmission system, which provides controlled application of the power. Merriam-Webster defines transmission as: an assembly of parts including the speed-changing gears and the propeller shaft by which the power is transmitted from an engine to a...
system was in the rear of the vehicle with rear drive sprockets
Sprocket
A sprocket or sprocket-wheel is a profiled wheel with teeth, cogs, or even sprockets that mesh with a chain, track or other perforated or indented material. The name 'sprocket' applies generally to any wheel upon which are radial projections that engage a chain passing over it...
. The transmission was derived from the ZF of the Panther. The functions of final drive and steering were combined in a single assembly; for each gear two turning radii could be selected. The engine was the Maybach HL295 12 cylinder of 29.5 litres, using fuel injection combined with spark ignition. The project goal was to bring the engine output to 1200 hp, implying a very favourable hp/litre ratio of over forty. This proved to be unrealistically ambitious, given the level of technological development at the time; in reality not even a ratio of thirty was reliably attained.
The hull sides were vertical, as in the case of the Tiger, while the front of the hull was in the first three prototypes evenly inclined at approximately 40 degrees from the horizontal, using sloped armour
Sloped armour
Sloped armour is armour that is neither in a vertical nor a horizontal position. Such "angled" armour is often mounted on tanks and other armoured fighting vehicles...
similar to that of the Panther and Tiger II. The corners between the glacis and the sides were truncated. The first two prototypes had a frontal protection level equivalent to about 120 mm "line-of-sight" thickness in the horizontal plane. The type was thus not particularly heavily armoured for its time. The weight increase with the third prototype was mainly caused by the larger turret and even in its fourth "uparmoured" form, doubling the frontal armour thickness, the AMX 50 was less well protected than its American and British competitors, themselves inferior in armour to the Soviet heavy tanks they had been created to fight. The fifth prototype used a lower cast hull, with a rounded frontal section for a better weight efficiency.
Above the massive hull, there was the oscillating turret
Gun turret
A gun turret is a weapon mount that protects the crew or mechanism of a projectile-firing weapon and at the same time lets the weapon be aimed and fired in many directions.The turret is also a rotating weapon platform...
, smaller, lighter and more compact than that of the Tiger; the sloped face of the upper part had a thickness of 85 mm. In the turret rear back there was the commander's cupola, well equipped with optical equipment. The turret had an optical rangefinder. The first two prototypes had twin 7.5 mm "Reibel" machine gun
Machine gun
A machine gun is a fully automatic mounted or portable firearm, usually designed to fire rounds in quick succession from an ammunition belt or large-capacity magazine, typically at a rate of several hundred rounds per minute....
s placed on top of the roof as an AA-weapon, a third was coaxial. In the first design proposal for a 120 mm version, the conventional turret had a high cupola armed with both a machine gun and a 20 mm MG 151 rapid fire cannon. However the third and fourth "120 mm" oscillating turret prototypes had a single 7.5 mm AA machine gun and a second 7.5 mm coaxial machine gun. For the production vehicles it was considered to install a coaxial 20 mm gun; lighter armoured targets could then be engaged without depleting the limited ammunition stock in the turret magazines. Despite the auto-loader, the crew was four: a second man was seated in the hull, functioning as radio-operator, but mainly needed to replenish the turret magazines from the hull ammunition stocks.
Design policy
The AMX 50 as originally planned, would have been a medium, not a heavy, tank. It was supposed to be light, well armed and above all mobile. When the first two prototypes were made, low weight had already been sacrificed in favour of a high protection level, but it was still supposed to be a quite agile vehicle, in the 45 - 50 tonne weight class, with a hp/tonne ratio of over twenty. Expectations were high: as General Molinié afterwards ironically put it, it was hoped to create a tank with the protection of the PantherPanther tank
Panther is the common name of a medium tank fielded by Nazi Germany in World War II that served from mid-1943 to the end of the European war in 1945. It was intended as a counter to the T-34, and to replace the Panzer III and Panzer IV; while never replacing the latter, it served alongside it as...
, the firepower of the Tiger
Tiger I
Tiger I is the common name of a German heavy tank developed in 1942 and used in World War II. The final official German designation was Panzerkampfwagen Tiger Ausf. E, often shortened to Tiger. It was an answer to the unexpectedly formidable Soviet armour encountered in the initial months of...
, the mobility and abundance of the T-34
T-34
The T-34 was a Soviet medium tank produced from 1940 to 1958. Although its armour and armament were surpassed by later tanks of the era, it has been often credited as the most effective, efficient and influential design of World War II...
, the reliability of the M4 Sherman
M4 Sherman
The M4 Sherman, formally Medium Tank, M4, was the primary tank used by the United States during World War II. Thousands were also distributed to the Allies, including the British Commonwealth and Soviet armies, via lend-lease...
and all that weighing less than the M26 Pershing
M26 Pershing
The Heavy Tank M26 Pershing was an American heavy tank briefly used in World War II and in the Korean War. It was named after General John Pershing, who led the American Expeditionary Force in Europe in World War I....
. At that time France hoped to regain its position as a Great Power; rebuilding its armaments industry served this goal. To build an indigenous battle tank was however not merely a question of national prestige. Europe as a whole was trying to recover from the devastations caused by the war and to assert a modicum of independence towards the two superpowers, the USA and the USSR. To this end in 1948 the Treaty of Brussels
Treaty of Brussels
The Treaty of Brussels was signed on 17 March 1948 between Belgium, France, Luxembourg, the Netherlands and the United Kingdom, as an expansion to the preceding year's defence pledge, the Dunkirk Treaty signed between Britain and France...
was signed, which among other things was also a common defence agreement. The AMX 50, superior in armament and mobility to the existing American and British designs, was seen as the logical candidate for a common European tank, to equip the future armies of the Western European Union
Western European Union
The Western European Union was an international organisation tasked with implementing the Modified Treaty of Brussels , an amended version of the original 1948 Treaty of Brussels...
defence organisation. The prototypes were proudly displayed during the 1950 Bastille Day
Bastille Day
Bastille Day is the name given in English-speaking countries to the French National Day, which is celebrated on 14 July of each year. In France, it is formally called La Fête Nationale and commonly le quatorze juillet...
parade. Somewhat inconsequentially, it was hoped that the Americans would fund such a tank, as the financial position of the European states would not allow them to rearm.
That same year, the situation changed drastically due to the outbreak of the Korean War
Korean War
The Korean War was a conventional war between South Korea, supported by the United Nations, and North Korea, supported by the People's Republic of China , with military material aid from the Soviet Union...
. Quickly the USA recommenced medium tank mass production, of the new M47 Patton
M47 Patton
The M47 Patton is an American medium tank, the second tank to be named after General George S. Patton, commander of the U.S. Third Army during World War II and one of the earliest American advocates of tanks in battle. It was a further development of the M46 Patton tank.-History:The M47 was the U.S...
. When this tank proved to be unsatisfactory, an even more advanced type was taken into production for the American forces, the M48 Patton
M48 Patton
The M48 Patton is a medium tank that was designed in the United States. It was the third and final tank to be officially named after General George S. Patton, commander of the U.S. Third Army during World War II and one of the earliest American advocates for the use of tanks in battle It was a...
; thousands of M47s were leased for free to the European allies, France included. The AMX 50 was suddenly made redundant as a medium tank, despite a "100 mm" prototype being sent in 1952 to the Aberdeen Proving Grounds for, successful, tests.
To save the project, a new rôle was found in the Soviet heavy tank threat. In the early fifties, NATO tacticians were worried by the strong armour of the Soviet vehicles, that seemed to be immune to the guns of the existing Western types. In response Britain would develop the Conqueror
Conqueror tank
The FV 214 Conqueror, also known as "Tank, Heavy No. 1, 120 mm Gun, Conqueror" was a British heavy tank of the post-war era. It was developed as a response to the Soviet Joseph Stalin IS-3 heavy tanks and carried a larger 120 mm gun compared to the 20-pounder gun carried by its peer the...
and the USA the M103 heavy tank
M103 heavy tank
The M103 heavy tank served the United States Army and the US Marines during the Cold War. Until the development of the M1A1 in the mid 1980s, it was the heaviest and most heavily armed tank in US service...
; abandoning the SOMUA SM, it was decided to let the AMX 50 evolve into a comparable type, even though other French heavy tank projects were in existence, such as the Char de 70 tonnes, a sort of "AMX 70". Already having a large chassis, the AMX 50 could in principle easily be adapted to carry the desired 120 mm gun — a derivation by the Atelier du Havre of the American gun, using the same ammunition — and had the advantage of a, on paper, very powerful engine. In practice there were many obstacles. Room could in fact only be found by increasing the height of the lower turret half, negating the advantages of the oscillating concept and creating a dangerous shot trap. The "uparmoured" version, with its deeper hull and flatter turret, was specially designed to counter this and make the vehicle immune in long range fire engagements, but further increased weight. In 1955 the AMX 50 was nevertheless very close to being ordered by the French government, that expected to produce the type for the reconstituted German Army also. A production was planned of a hundred for 1956. This decision had to be delayed however, due to the fact the engine problems had not been solved: reliability could only be assured if the output was limited to 850 hp, causing a mediocre hp/tonne ratio of about 13:1.
The delay proved fatal to the project. In the late fifties, swift advances in hollow charge technology led to an increased vulnerability for heavy tanks. Mobility thus gained a priority over protection and the very concept of a heavy tank became obsolete. As a result the project was changed again in intention, now trying to present itself as an agile main battle tank, with the same gun as the Conqueror but much lighter and more powerful. This failed as it was much too large and expensive; oscillating turrets also became unpopular as they were inherently difficult to protect against nuclear and chemical contamination. The engine problems with the Maybach were never overcome and lowering the hull to save weight, as was done for the final prototype, made it impossible to install a larger engine. Recognizing that the problem of combining excellent mobility with heavy armour was for the time being irresolvable, the AMX 50 project was terminated; the priority given to mobility demanded a new design concept, leading to the AMX 30, the lightest MBT of its time. Only in the early eighties would France again attempt to combine heavy armour and armament in its tank designs, beginning with the later AMX 32 prototypes. The AMX 50 would not be a complete waste of time and effort however, as much technological knowledge had been gained from which the AMX 30 would profit.
In the Musée des Blindés
Musée des Blindés
The Musée des Blindés or Musée Général Estienne is a tank museum located in the Loire Valley of France, in the city of Saumur. It is one of the world's largest tank museums....
at Saumur
Saumur
Saumur is a commune in the Maine-et-Loire department in western France.The historic town is located between the Loire and Thouet rivers, and is surrounded by the vineyards of Saumur itself, Chinon, Bourgueil, Coteaux du Layon, etc...
an AMX 50 is shown, a combination of the last cast hull and the Tourelle D.