The general AMX 50 project was the heaviest of a trio of French AFV 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.
| AMX 50 | |
|---|---|
| Type | Heavy tank |
| Place of origin |  France |
| Specifications | |
| Weight | 57.8 metric tonnes |
| Length | 7.35 m |
| Width | 3.4 m |
| Height | 3.35 m |
| | |
| Armor | 80-120 mm |
| Main armament | 120mm |
| Secondary armament | 2 x 7.5mm machine guns |
| Engine | Maybach HL 295 12VC 850 hp |
| Power/weight | 15 hp/ton |
| Suspension | torsion bar |
| Speed | 51 km/h |
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 Tank and the Panther tanks 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 guns 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.
