Char D2 - Development

Development

At the same time the Char D1 was ordered, a plan was made to develop a more modern tank. The Char D1 had already departed from the pure infantry support concept and evolved from a light into a medium tank, capable of fighting enemy armour; this made it the obvious candidate to be quickly changed into a lighter alternative for the Char B1 battle tank, needed because the latter type was in danger of being forbidden by an expected armaments limitation treaty under the auspices of the League of Nations, imposing an upper weight limit of twenty metric tonnes for armoured fighting vehicles.

The Direction de l'Infanterie proposed on 23 January 1930, in a letter to the ministry of defence, to build a better armoured tank, using 40 mm plate, that nevertheless would be swifter at 22 km/h by fitting a 120 hp engine. The weight however should rise only from 14 to 15.5 metric tonnes, made possible by using welded instead of riveted armour plate. On 14 April the plan was approved and in May Louis Renault was contacted, who agreed to develop this type as the Char D2, together with a colonial tank, the Char D3, which would closely resemble its sister project.

To introduce the new welding technique entailed hiring foreign experts, which was very expensive. Renault insisted that the costs would be paid in advance by the French Army, which however had no corresponding budget available. On 8 December 1931 the deadlock was broken by a new agreement: Renault would first build a prototype with a riveted hull, the Renault UZ, which was delivered in April 1932. First the type was tested in Rueil; in May 1933 field tests were carried out by 503e RCC. The type was accepted for production, which decision was affirmed by the Conseil Consultatif de l'Armement on 12 December 1933.

At that moment however, Germany had just left the League of Nations altogether, making the limitation talks irrelevant, from which then France retired also. Existing plans to produce 750 Char D2s, 150 per year for the period 1935-1939, (six hundred to equip twelve battalions and 150 as a matériel reserve) were immediately reduced. On 14 January 1934 the High Command confirmed only the plan of a first production order of fifty. All these decisions were taken on the basis of experience gained with the riveted prototype, though it was well understood that from it no firm conclusions could be drawn on the quality of the intended welded type.

Meanwhile two welded prototypes had been ordered in December 1932. These were finished in August 1933, but only delivered in November. From December 1934 till the summer of 1935 the Commission de Vincennes used the three available prototypes to test different engine configurations. The riveted hull was equipped with a 120 hp petrol engine; the other two with diesel engines. These were rejected in favour of the petrol engine even though its combination with the intended welded hull had not yet been tested.

Nevertheless on 29 December 1934 the order of fifty hulls was granted to Renault, at a price of 410,000 French Francs per piece. The turrets were produced separately. First the ST3 turret (Schneider Tourelle 3) had been tested in 1933; then it was considered to use the ST2, then seen as a possible standard turret for all heavier tanks, but finally a choice was made for the APX1, originally developed for the Char B1, costing ₣ 200,000 which brought the unit price to ₣ 610,000. The fifty vehicles were only delivered from May 1936.

Due to this delay a planned second order of a hundred, to bring total production to 150, to be made in 1935, was cancelled. It had been assumed that the lighter Char D2 could be quickly produced as an interim type, to speed the formation of the first Infantry armoured division of the Infantry.