Hotchkiss H35 - Description

Description

The Hotchkiss H35 was a small vehicle, 4.22 metres long, 1.95 m wide and 2.15 m tall and weighing 11.37 tonnes. The hull consisted of six cast armour sections, bolted together: the engine deck, the fighting compartment, the front of the hull, the back of the hull and two longitudinal sections left and right forming the bottom. The casting allowed for sloped armour, avoiding shot traps, to optimise the chance of deflection but the protection levels did not satisfy the Infantry. Maximum armour thickness was not the specified 40 mm but 34 mm. There were persistent quality problems, worsened by the fact that many subcontractors had to be used: at first the armour was made much too soft; when hardness was increased it became brittle and full of bubbles and hence weak spots.

There was a crew of two. The driver sat at the right front, behind a large cast double hatch and next to the combined gearbox and steering unit. Driving the vehicle was very hard work. The Hotchkiss lacked the Cleveland differential ("Cletrac") of its Renault competitor, and it responded unpredictably to direction adjustments. The brakes were little help in compensation: they were too weak, especially when driving down a slope. No less troublesome was the gearbox: it was difficult to engage the highest fifth gear and so the theoretical top speed of 28 km/h was rarely reached. The inevitable rough handling of the tank by the driver resulted in much wear and tear. Mechanical reliability was poor.

The suspension consisted of three bogies per side - each formed of two bell cranks arranged as "scissors" with springs at the top. The first ten production vehicles, which can be considered as forming a separate preseries, had curved bogie sides; in later vehicles the bogies had straight sides. The bogies superficially resembled the R35 type, but used horizontal helical springs instead of rubber cylinders. The tank was powered by a 78 hp six-cylinder 3480 cc engine which was on the left of the engine compartment. A 180 litre fuel tank on the right gave a range of 129 kilometres. A cooling fan drew air through the radiator and was also expected to cool the fuel tank.

The APX-R turret was the same standard type as used on the R35 and R40 tanks, made of 40 mm cast steel and armed with the short 37 mm SA 18 gun, which had a maximum armour penetration of only 23 mm (0.91 in). Traverse of the turret was with a handwheel. The commander sat in a saddle suspended from the turret. The tank carried about 100 rounds for the gun and 2,400 rounds for the coaxial 7.5 mm Reibel machine gun - 37mm ammunition racked on the right hand side of the hull and 7.5mm on the left. The turret had a rotating cupola with a visor but there was no hatch in the cupola. Apart from the cupola there were protected vision devices, a binocular periscope and diascopes, to the front beside the gun and to each side. For access there was a hatch at the back of the turret. When opened, the commander could sit on it for better observation, but this left him very vulnerable and slow to reach the gun. The alternative was to fight closed-up, observing through the hatchless cupola. The Cavalry liked neither this arrangement nor the weak gun. The latter problem was lessened somewhat by enlarging the breech so that special rounds with a larger charge could be used. This increased muzzle velocity to about 600 m/s (2,000 ft/s) and maximum penetration to about 30 mm (1.2 in). Only a small part of the tanks with the Cavalry alone were modified however, because it greatly increased barrel wear. In the Spring of 1940 the original diascopes of the Chrétien type were gradually replaced with episcopes, offering more protection.