Renault R35 - Development

Development

The development plan of 1926 foresaw the introduction of a char d'accompagnement, a cheap mass-produced light tank to replace the Renault FT 17 of World War I vintage, to make it possible for the standard infantry divisions to execute combined arms infiltration tactics, seen as the only viable method of modern offensive warfare left for non-motorised units. The French army did not have the means to motorise more than a few select divisions. In 1930 this plan was replaced by a new one, giving more precise specifications. The first tank to be developed to fulfil its requirements, the Char D1, proved to be neither cheap nor particularly light. In 1933, Hotchkiss offered an alternative solution, the later Hotchkiss H35. For political reasons this proposal was turned into the Plan 1933 and the whole of French industry was in August 1933 invited to propose possible designs. Fourteen companies responded (among which Delaunay-Belleville) and five submitted a prototype: Hotchkiss itself, the Compagnie Général de Construction des Locomotives, APX, FCM and of course France's prime tank producer: Renault. Fearing that his rival Hotchkiss might well replace him as such, Louis Renault hurried to finish a vehicle; construction was soon in such an advanced stage that the changes in specification issued on 21 June 1934, to increase armour thickness from 30 to 40 mm, could not be implemented. On 20 December 1934 Renault was the first to deliver a prototype, with the project name of Renault ZM, to the Commission de Vincennes.

In the spring of 1935 this vehicle was refitted with heavier armour and a standard APX turret, attached by the Atelier de Rueil between 18 and 25 April. The prototype was still being tested when international tensions increased due to German re-armament. This prompted an urgent demand for swifter modernisation of the French tank fleet. The ZM was to be put into production immediately. On 29 April 1935 an order of 300 was made, even before the final model could be finished, at a price of 190,000 French franc per hull (unarmed, without the engine and turret, the overall export price was ca. 1,400,000 francs in 1939, that is ca. 32,000 dollars by 1939 standards). The first series production vehicle was delivered on 4 June 1936 and had to be extensively tested again as it was different from the prototype.