BDR G1 B

In 1935, the French Infanterie still lacked a satisfactory medium tank. While a reasonably effective heavy breakthrough tank in the form of the Char B1 was available, as well as several light infantry tanks about to enter production (namely, the Renault R35, Hotchkiss H35 and FCM 36, the only medium tanks available were the disappointing Renault Char D1 and only slightly improved Renault Char D2. At least 250 medium tanks would be needed to equip the planned organic tank battalions of the five mechanized infantry divisions, which would be the main Infanterie force for executing strategic offensive and defensive operations. The Cavalerie already had a good medium tank in the form of the SOMUA S35, but the Infanterie rejected it for use on account of the S35's limited climbing capabilities. Inter-service rivalry also played a role in this rejection, as the Infanterie wished to assert its dominance over the Cavalerie in the field of tank design.

The Twenty-Tonne Tank

Thus, on 18 December, the Infanterie issued its first specifications for a Char Moyen d'Infanterie de 20 tonnes ("20 tonne medium infantry tank"). The specifications called for a road speed of 50 km/h, an off-road speed of 20 km/h, a range of 400 km, trench crossing capability of 2 m, a wading depth of 120 cm, climbing capability of 80 cm and 45° slope. Armament was to consist of a 47 mm gun and a 7.5 mm machine gun, with an armor thickness of 40 mm. The hull was to be completely sealed against chemical weapons, and a radio was required. The weight limit of 20 metric tonnes was stipulated because of railroad, bridge-carrying, and pontoon capacity constraints.

In May 1936, the Conseil Consultatif de l'Armement invited French industry to initiate design studies for the new 20 tonne tank. However, at the same time it was increasingly realized that the Char B1 was overly complex and expensive, and was 2 tonnes heavier than necessary due to the use of riveted armor plate instead of more modern welding and casting techniques. The 20 tonne tank promised to be lighter, more mobile, cheaper and easier to produce, and also easier to train crews on. It was thus decided that the 20 tonne tank would also serve as the future char bataille ("battle tank") of the Infanterie, replacing the Char B1. The specifications were subsequently changed in October, calling for protection equivalent to that of the Char B1 (60 mm all around), increased trench crossing capability (250 cm), and armament of a high velocity gun capable of eliminating all expected enemy medium tanks as well as two machine guns. The other requirements remained the same. These specifications were highly ambitious, and the vehicle promised to be the most potent and modern French tank yet developed. This also meant that development would take some time, as the tank was too advanced for French industry at the time.

Char G

At the same time, debate was raging about the future use of the tank in the Infanterie. On one side were officers like Charles de Gaulle, who proposed that the Infanterie raise its own armored divisions similar to the DLMs (Divisions Légères Mécaniques - "Mechanized Light Divisions") of the Cavalerie or the German Panzerdivisionen - balanced forces with organic mechanised infantry and artillery, flexible enough to fulfill all possible tactical roles. More conservative officers opposed imitating the Cavalerie and insisted that the Infanterie should stick to its traditional role, that of the breakthrough. Some wanted the limited funds to be spent on producing a sufficient number of light infantry tanks to give each division its own organic tank battalion. Others contended that only heavy tanks should be built. The 20 tonne tank, now known as the Char G, was intended to be both mobile and heavily armored enough to spearhead breakthroughs, and only made sense if used in German-style armored divisions. Until the debate was settled, the future of the Char G remained uncertain.

Despite this, French industry was very interested in the Char G project, as it promised to become France's major tank-building program. With it would come lucrative state investments at a time when French industry was still reeling from the effects of the Great Depression. Seven companies submitted designs between late 1936 and early 1937: Établissements Baudet-Donon-Roussel (BDR), Société Nouvelle des Forges et Chantiers de la Méditerranée (FCM), Renault, Fouga, Lorraine de Dietrich, Société d'Études et d'Applications Mécaniques (SEAM), and Société d'Outillage Mécanique et d'Usinage d'Artillerie (SOMUA). Reports were issued on each of the proposals, only SEAM and Renault's projects were sufficiently advanced for construction of prototypes to be approved, their good connections with the French military having allowed them to begin design work even before the specifications had been officially issued. The proposals of BDR, Lorraine de Dietrich, and Fouga were kept under consideration until further studies on their feasibility had been completed. On the instigation of Prince André Poniatowski, head of a design bureau subcontracted by SEAM, the Char G specifications were changed in November 1937 to require a hull-mounted 75 mm gun as the Char G's primary armament, which was unsurprisingly a feature of SEAM's proposal. This caused many problems for the other competitors, as their designs had no room for such a large weapon in the hull. This change in requirement, along with the increase in armor demanded added about 4 tonnes to the designs, and as of 20 February 1937, none of the designs met the weight limit of 20 tonnes, and were projected at 23-35 tonnes. Louis Renault's design featured a 75 mm gun mounted in the turret, and back in 1936 he had proposed this arrangement as an alternative, which was well-received. Capitalizing on this, he bribed a high-ranking officer of the Direction de l'Infanterie to change the design requirements yet again, this time making a 75 mm gun in the turret mandatory. This forced Renault's competitors to completely redesign their proposals, giving Renault a huge advantage and inevitably causing large and, as Renault hoped, fatal delays to the competition's proposals.

Char G1

By late 1937, the project had been renamed Char G1, and all prototypes then authorized received official designations: G1L (Lorraine), G1R (Renault), G1B (BDR), G1F (Fouga), G1P (SEAM). The SOMUA and FCM projects had been discontinued for being too vague or lacking innovation, along with the fact that these two companies had their hands full manufacturing other types. On 1 February 1938, the Direction de l'Infanterie issued a third major change to the specifications. The maximum weight was increased to 35 tonnes in order to fit the 75 mm APX 32-calibre gun in a turret (known as the 75 mm SA32 in-game). The ever-changing design requirements caused most companies to slow the design process, as they were unwilling to invest much money in an ever more complex project with uncertain prospects. In order to speed up the process, on 8 June 1938 Maurice Lavirotte of the Atelier de Construction de Rueil (ARL), the French Army's workshop, was dispatched to assist the companies with construction. If armor plate was not available for the companies, boiler plate was permitted in the construction of the prototypes.

New Specifications

On 12 July 1938 a much more detailed list of specifications was given. In general they called for a tank that was powerfully armed, immune to standard anti-tank guns and possessed excellent tactical and strategic mobility. In detail, the specifications demanded a long, high velocity, semi-automatic 75 mm 32-calibre gun as the main armament; a 7.5mm machine gun in the turret that can also serve as an anti-aircraft weapon, a machine gun in the front of the hull or the turret, a minimum ammunition load of 100 rounds for the main gun and 30 magazines for the machine guns, an empty weight of 30 and a combat weight of 32 tonnes. The engine was to be able to be both electrically and manually started, while the tracks were to be fully accessible. A maximum speed of 40 km/h (average 30 km/h) on roads and 20 km/h offroad was required. Two fuel tanks were to give a range of 200 km or 8 hours endurance offroad. Climbing capability was demanded to be 90 cm and 85% on a solid or 65% on a wet slope, while trench-crossing capability was to be 250 cm and the wading depth would be 120 cm. For the first time, dimensional limits were also set: the width was to not exceed 294 cm to facilitate rail transport, the absolute height of the fighting compartment was to not exceed 120 cm, but yet be sufficient to hold a sidedoor. With regards to the gasproof armor, the demanded thickness remained at 60 mm, but the use an appliqué armor was forbidden. The armor could be cast — with the sections connected by bolts or, preferably, gudgeons, or electrically welded. Automatic fire extinguishers were also required. The crew were to have advanced vision and fire-control equipment. The cupola, armed with the secondary 7.5 mm machine gun, was to have have a large episcope to which the main turret was slaved, allowing the commander to lay the 75 mm gun on the target himself. The cupola would also be fitted with an optical telemetric rangefinder. The gun was to be a 32-calibre 75 mm gun. Despite its short length, the gun would have good armour penetration using Brandt tungsten armor piercing subcalibre ammunition. None of the projects in the summer of 1938 could meet these specifications without a fundamental redesign.

In France during the 1930s, tank turrets were usually designed separately from tank hulls, in order to serve as standard types usable on many different vehicles. On 1 June 1938 the commission determined that three teams, those of ARL, FCM, and Renault, were to develop new turrets capable of being fitted to the Char G1 under the new specifications. They were invited to make the necessary changes and consider existing or new high velocity 75 mm guns. In July 1939, ARL produced a prototype of both a turret, the 5.7 tonne ARL 3 fitted with a turret-basket and having a turret ring diameter of 188 cm, and a 75 mm gun, which had been developed for the FCM F1 super heavy tank project. Similarly, FCM developed a modified 7.5 tonne version of the welded octagonal auxiliary turret on the FCM F1, equipped with an advanced semiautomatic loader and a turret ring diameter of 185 cm. As a low-risk project, FCM also developed the welded, octagonal F4 turret that had been developed from that of the Char 2C super heavy tank, and was equipped with the ubiquitous 75 mm mle. 1897 field gun.

Char G1B

Établissements Baudet-Donon-Roussel proposed to build a tank with a similar general layout to the Char B1, including the distinctive high-running tracks but with seven road wheels per side that did not require daily lubrication, instead using sealed ball-bearings. The track had a continuous rubber (Pendelastic) inner lining. The project had the following dimensions: a length of 556 cm; a width of 280 cm, and a height of 285 cm. It was the largest and heaviest of all proposals with a weight of 28.5 tonnes. Track width was to be 35 cm, the normal wading depth 145 cm; BDR thought it also possible to make the tank fully submersible to cross rivers while being guided from the river bank. It was planned to install an air-cooled Potez 12V 320 hp engine, placed transversely in the hull. The transmission was to be petrol-electric and of the Gebus-Roussin type. The fuel tank would have a capacity of 520 liters. The armament would consist of a 75 mm SA35 howitzer in the hull with 70 rounds. In the 1937 configuration it would make use of the APX4 turret with a 47 mm SA35 gun; 102 47 mm rounds would be carried. As the hull was wide enough to place the 75 mm gun in the middle, the turret should have been moved to the left, but this was forgotten in the proposal, as the commission pointed out.

When the changed specifications asked for a 75 mm gun in a turret, the project threatened to become much too heavy, since the hull was already so large. The commission in the summer of 1938 urged BDR to remedy this somehow, but the problem proved to be insurmountable. A proposal to install a more powerful 350 hp Renault engine only partly compensated for the reduction in mobility. It also transpired on 13 April 1939 that the intended ARL 3 turret brought the Char G1B's height to 325 cm, and could not be fitted without making the design too wide for rail transport. The weight, now projected at 37.5 metric tonnes, exceeded pontoon limits. The project was suspended on 10 September 1939, even though a prototype had been ordered in March 1939 by the Ministère de la Guerre. A wooden mockup was all that was ever finished, and even that could not be shown to the commission because it was, for security reasons, constructed in an enclosed room lacking a sufficiently large exit. No complete prototype was ever built. Despite this, the G1B's chassis would later be used as the basis for the ARL V39 assault gun.

Historical Inconsistencies

• There is no indication that the 90 mm DCA 30 was to ever have been fitted to any of the G1 projects.
• The 75 mm Long 44 was developed in 1944, long after the G1B had been cancelled.

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