Char B1 and Char B1bis
Top: Char B1 bis in action, May 1940. Centre: B1 with short 47mm. Bottom: Char B1 bis under trial 1940
The initial development of the Char B was essentially work of General J.E. Estienne who was in charge of the Section Technique des Chars de Combat until the late 1920s. Under the Programme de 1921 he initiated studies with five different firms on a 15 ton tank that was to have a 75mm or 47mm gun in a hull mounting and which was virtually a development of the ideas contained in the war time Schneider and St Chamond tanks. Mock ups of four tanks, of about 19 tons, were presented at the Atelier de Construction de Rueil (ARL) in May 1924 - two from Schneider-Renault , one from Forges et Acieries de la Marine et d'Homecourt (FAMH) and one from FCM. Following technical trials authority was given in January 1926 for three prototypes to be built, making use of the FCM suspension, the Renault engine and the transmission from Schneider, whilst the Section Technique was so encouraged by the success with the Naeder steering system to develop this with the Societe des Batignolles as the basis for aiming the gun. It was not until March 1927, however, that firm orders were placed with FCM, Renault and FAMH, while ARL remained in control of the project as design parent. Two tears later, in January 1929, the first prototype was completed at Rueil, with the second coming also from ARL and the third from Marseilles in mid-1931.
The prototype of the Char B weighed 25 tons, carrying a crew of four protected by a maximum of 25mm of armour. In common with the general practice of the period the armament carried a preponderance of machine guns for 'man-killing', and included one 75mm in a hull mounting beside the driver, two fixed machine guns in the front hull, and two coaxially in the one man turret. A Renault 6 cylinder engine (180hp) gave the tank a speed of 28kph, and, carrying 800 litres of fuel, a radius of action of 10 to 12 hours. After the initial technical trials and modifications the first prototype was presented to the trials establishment at Bourges in May 1930 and, by September, was reported as ' representing a considerable progress on earlier weapons'. In October 1931 all three prototypes were brought together as a trials unit for tactical exercises at Mourmelon, for firing and mobility trials. The equipment performed ' perfectly'.
Development was already lagging behind demands however. In October 1930 the War Minister initiated studies one a new char de bataille, based on experience with the Char B1, and he presented a revised statement on the required characteristics, demanding high strategic mobility, speed and cross-country performance to move ahead of the infantry, heavy firepower and wireless. Although the battle tank was still tied to support of the infantry, it was at last officially accepted as an offensive weapon that was necessary 'in all phases of battle from the advance to contact to the pursuit'. Specifications were drawn up and design studies started on a new tank that was tentatively named the Char B2. Its weight was limited to 35 tons, with a crew of 4 or 5 enclosed in 40mm armour, having a top speed of 40kph, mounting a 75mm gun and two machine-guns with limited traverse, and the fighting compartment protected against gas. These studies were, however, not pursued to production.
While these particular studies were not pursued, the prototype trials continued on the Char B1. By 1935 its armour had increased to 40mm and weight to 28 tons. Its advanced technical merits had confirmed its position as a powerful weapon. There were some reservations about its age, since the basic design was now 10 years old, whilst the complexity of components meant that it was costly to build and demanding of a high proportion of regular soldiers for operation and maintenance. The moves of the German Army into the Rhineland in March 1935 helped to galvanise the situation and mobilisation became more urgent. In April 1935 the decision was made to build 40 of the Char B1 up-armoured to 60mm and to be known as the Char B1 bis.
This still meant further design work and trials to accommodate the extra armour plate, but production began anyway, based on the prototypes with armour to 40mm and with the cast APX 1 turret carrying the SA 34 47mm gun, and a machine gun, effectively the same turret as on the Char D2. 35 tanks were delivered in this configuration before the improvements were introduced, and the earlier tanks are usually referred to as Char B1. The new Char B1 bis now weighed 32 tons and mounted and mounted and engine boosted to 300hp to carry the extra five tons, but at the expense of a reduced radius of action. The turret was now the APX 4 with slightly thicker armour and the longer SA 35 47mm gun.Production continued slowly in peace time but slowly the tank battalions were equipped with this formidable tank. The Char B1 bis became the main French heavy battle tank with 365 built in addition to the 35 Char B1s.
Technical Description of the Char B1 bis
The hull of the Char B1 was formed by a few cast armour components bolted together with armoured plates resting on two cross members and on girders along each side. the suspension assemblies, which incorporated vertically mounted coil springs, were fixed to these girders so that the springs projected upwards into the hull; skirting plates protected the suspension system below. The hull was divided by a fireproof bulkhead into two parts, with the fighting compartment at the front holding the crew of four, and engine and transmission at the rear.
The driver, who was a key member of the crew in that he also fired the 75mm gun, sat on the left front. He was the only member of the crew apart from the commander who could see outside the tank. Driving controls included a steering wheel (connected by chains and rods to the Naeder hydrostatic system), a brake lever on each side with ratchet, the gear lever to the right hand, and the normal accelerator, brake and clutch pedals. Fixed to a shield on his right was the elevating handle for the 75mm gun that was mounted behind a mantlet bolted to the hull front to the right. Movement of the gun in elevation operated the linkage which turned prismatic binocular sights mounted in the driver's hood on an axis parallel with the gun trunnions; the sights were rotated behind a pair of vertical slits beneath the driver's episcope. The 75mm gun was fixed in azimuth, however, and laying for line could only be done by turning the whole tank. An unusual feature for a tank gun was the air-blast gear fitted to the 75mm gun and supplied from a Luchard air compressor. Fumes from the gun were literally blown out through the muzzle in a way that is standard in naval gun turrets.
The driver was also responsible for firing by cable the fixed machine gun that was mounted low in the hull to the right of the 75mm gun, although, by repositioning the firing handle to the tank roof, this could be done by the crew commander. There was limited movement of the machine gun in elevation by a turn-buckle on the mounting but, like the 75mm gun, the machine gun was fixed for line and had to be aligned by turning the tank itself.
The loader's duties were to serve the two hull guns; in action he was a busy man as his tasks include fitting of fuses to the 75mm shells, stowed separately, and he was also needed to pass ammunition to the tank commander in the turret when the commander had used the rounds immediately to hand. Ammunition for all weapons was stowed in bins or racks on the walls or under the floor of the fighting compartment, while some was also stowed in the engine compartment.
The wireless operator was seated, like the loader, at the base of the crew commander's seat. the crew commander was the sole occupant of the turret, which was carried centrally towards the rear of the fighting compartment. the cast APX 4 turret of the Char B1 bis, mounting the 47mm SA35 gun and machine gun equipped with electric power traverse, was identical with that on the Somua S35, while the APX 1 turret on the 35 Char B1s, with less armour and mounting the shorter SA34 gun, was identical to that on the Char D2. This part of the fighting compartment, known as the 'command post', included the wireless set, the inter-communication control box, a binnacle-mounted compass and a gyroscopic direction indicator. Te latter was driven by compressed air supplied from the same Luchard air compressor through a reserve bottle mounted beside the driver.
The main entrance to the hull was by a door in the right side, while the driver had a hatch over his head and there was a hatch in the rear of the turret for the commander. An escape hatch was provided in the hull floor, where there were other hatches for the disposal of empty shell casings, and there was another escape hatch in the roof of the engine deck, reached via the gangway alongside the engine.
The engine compartment was itself divided into three parts - right, left and centre - and the engine, with associated power train to the gearbox and rear sprockets, filled the centre. On the right a narrow gangway, entered through a door in the bulkhead, gave access to some components, fuel gauges and ammunition. Two self-sealing fuel tanks were on the right side with another on the left where two radiators and fans were mounted along the axis of the tank, so that cooling air was drawn from above the gangway, across the engine and out through grill louvres on the left side of the tank.
The engine, a Renault 6-cylinder aircraft engine with magneto ignition, incorporated an unusual compressed air starting system in addition to the normal electric starter motor. This Viet system provided independent ignition and a source of mixed fuel and air under pressure to the cylinders, which was sufficient to turn the engine slowly until the normal firing system started.
The gearbox and transmission unit incorporated a differential connected directly to the final drive and sprockets, together with an auxiliary differential controlled by the Naeder hydrostatic system for steering. In conjunction with this double differential unit the Naeder system controlled power distribution to each track and permitted the infinitely fine variations in steering which were vital in aiming the hull guns. Brake drums were mounted externally at each end of the auxiliary differential, operated with servo-assistance by the driver's hand brakes and pedal. If necessary, these brakes could be used for coarse steering.
The suspension was a development of the Holt tractor type, comprising three main assemblies each side, each of four bogies mounted in pairs on plates pivoted at the centre. Each of these plates was mounted at the end of a similar one balanced at the base of vertically mounted coil springs, while semi-elliptical leaf springs also came into play as dampers under extreme compression. In addition, but not bearing the weight of the tank, there were four independently mounted bogies (three forward, one rear) controlled by leaf springs. Unusually, the front idler wheel (tensioner) was also spring-mounted, and adjustments for track tension were made from inside the fighting compartment. All this demanded considerable lubrication of bearings and guides, but this task was made easier with an arrangement of grease nipples in four groups each side behind small flaps in the armoured skirting plates. The track pins, however, required greasing individually.
All in all the Char B was a sophisticated tank with some technically advanced features, but its very complexity was a disadvantage in manufacture and maintenance, whilst its layout and demands on the crew hindered an efficient use of the tank in battle. It was greatly respected by the Germans, who dubbed it the Kollossus, and the tanks of 3rd Armoured Division certainly gave GrossDeutschland a hard time at Stonne. One of the main challenges for the French was the late mass-production of this vehicle; this gave the crews very little time to become familiar with what was a very complex tank. It was not until Spring of 1940 that production reached a peak. To fight the Char B1 well required excellent cooperation and understanding between the crew, and this can only come with constant practice. Coupled with a high maintenance bill the tank could only really be at its best with experienced troops.
Characteristics and Tabulated Data Char B1
Engine: Renault nominally 250hp, 6 cylinder, bore/stroke 140 x 180mm, 16,625cc producing 272hp
Gearbox: 5 and reverse
Max speed: 28kph
Range: 8 to 10 hours
Petrol capacity: 400l
All up weight: 27,195kg
Armour: 40mm max
Crew: 4 commander/turret guns gunner in turret, driver/mechanic/hull guns gunner, mechanic/loader and radio operator in hull (5 crewmen in company command vehicles; an extra radioman was carried to operate the extra radio)
Armament: Turret. coaxial in APX 1 turret: SA 47mm gun Model 1934 with 50 rounds and 7.5mm MAC 31 machine gun. Hull: SA 75mm Model 1935 with 80 rounds and fixed MAC 31 with elevation only, no traverse. 4,800 rounds in total for both machine guns
Width of vehicle: 2.50m
Length: 6.37m
Height: 2.79m
Char B1 bis Characteristics for Command Decision
Char B1 bis Companies 10 May 1940
Example Char B1 bis Organisation for Command Decision: 1st Armoured Demi-Brigade with 28th and 37th Tank Battalion (BCC), 1st Armoured Division (DCR)
Headquarters: Command B1, medium baggage truck, medium supply truck, support stand
28th Armoured Battalion (BCC)Headquarters: Command B1bis,3 x Company: Command B1bis, B1bis
37th Armoured Battalion (BCC)Headquarters: Command B1bis,
3 x Company: Command B1bis, B1bis
