Char D2
The Char D2 was a French medium tank of the interwar period.
In 1930, at a time the Char D1 had not even entered production, the Renault company agreed to build a better armoured version called the Char D2. By not using old-fashioned rivets, it was hoped to save weight. The tank should have the potential to serve as an alternative in the role of battle tank for the heavier Char B1, should the latter be forbidden by treaty. The failure of the armament limitation talks resulted in a severe reduction of the projected manufacture, now in the form of an interim tank. Organisational difficulties with Renault caused the actual production of a first series of fifty to be delayed to the years 1936 and 1937. A second series of fifty was ordered in 1938, despite indications that the type was mechanically unreliable, as a possible cheaper addition to the expensive Char B1. With the latter type, in case of war, only a limited number of armoured divisions for the Infantry Arm could be raised; the Char D2 created the prospect of increasing this. Due to Renault's financial problems, this second, partially improved version, was only realised in early 1940, bringing total production to a hundred.
The three prototypes were, among others, fitted with turrets of the Renault FT during a mock-up. The production models of the first series had the APX-1 turret, armed with a short 47mm SA34 tank gun. The second series used the much more powerful 47mm SA35 tank gun; from March 1940 this was retrofitted to a number of the older vehicles, despite a parallel project to rebuild them as flamethrower tanks.
In 1937 the type equipped one tank battalion, which was considered an elite unit, as part of Charles de Gaulle's regiment. It was well-trained in the use of advanced tactics, including the use of radio-sets. In 1940 the effectiveness of this unit had much diminished, because of the worn-out state of its tanks, aggravated by the decision to raise three autonomous tank companies with the new vehicles, even though insufficient trained crews were available. Nevertheless, the Char D2 units fought tenaciously during the Battle of France, losing most of their tanks to mechanical breakdown instead of enemy action.
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, 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 had been tested in 1933; then the ST2, at the time seen as a possible standard turret for all heavier tanks, was considered but finally a choice was made to use the APX1, originally developed for the Char B1, costing ₣ 200,000. This turret brought the unit price to ₣ 610,000. The fifty vehicles were only delivered from May 1936.
Due to this delay a planned second order, to be made in 1935, of a hundred, to bring total production to 150 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.
Description
In essence the Char D2 was an improved Char D1. The different turret type used, increased its height somewhat to 266.6 centimetres; the hull was 175.5 centimetres high. The length of the hull, without tail, was 546 centimetres; its width was reduced to 222.3 centimetres through the use of a narrower track, 35 centimetres wide. The suspension was largely identical but the top rollers, to which a tension wheel was added, were placed somewhat higher to prevent track resonance, a persistent problem with the Char D1. The armour plate covering the three vertical coil springs consisted of six instead of eight panels; mud-chutes were added below each top roller. There were three bogies per side, each with four road wheels, a coil spring and two shock absorbers. In front, and at the back below the sprocket, there was a tension wheel with its own damper; identical to the road wheels proper they brought the total number of such wheels to fourteen. Another change was the fenders with large stowage bins that gave the false impression of being part of the main armour.The production vehicles used far less welded sections than at first intended. To reduce the price, Renault opted to implement a novel construction technique, using large flat screws, serving both as bolts and, applied heated, as rivets, attaching the main armour plates to each other by means of thin connecting steel strips. This way no internal girders, forming a real chassis, were needed. The armour plates were 40 mm thick.
Like with the Char D1 there was a crew of three, but the radio-telegraphy operator sat to the right of the driver instead of the commander, and the antenna, of the ER52 set, has been moved to a position next to him. To make room a hull machine-gun was absent. This new configuration had been demanded to create a roomier fighting compartment. Two command vehicles, series numbers 2016 and 2049, had a second antenna on the left to serve their ER51 long range set. The engine power was increased considerably to 150 hp by installing a Renault V-6 9.5 litres motor, but as the weight increased to 19.75 instead of the intended 15.5 metric tonnes, the gain in maximum speed was only to 23 km/h. The gear box had four speeds. Four fuel tanks together holding 352 litres allowed for a range of a hundred kilometres. The wading capacity was 120 centimetres, a trench of 210 centimetres could be crossed, an obstacle eighty centimetres high or a slope of 50% climbed. The hull had a fixed 7.5 mm machine-gun low in the glacis on the right side.
The commander was the sole occupant of the APX1 turret, acting also as gunner and loader for the 47 mm SA34 gun, which had a limited anti-tank capacity, and the optionally coaxial 7.5 mm Châtellerault machine-gun. The gun could fire two types of ammunition: a HE called the Obus D with a shell weight of 1250 gramme and a muzzle velocity of 490 m/s; and an APHE, the Obus B Modèle 1932, with a shell weight of 1410 gramme, an explosive charge of 142 gramme and a muzzle velocity of 480 m/s. It rendered an armour penetration of just about 25 millimetres at a distance of a hundred metres, barely enough to be effective against light armoured vehicles.
Second production batch
The first fifty vehicles, series numbers 2004 - 2053, having been delivered between 9 May 1936 and 23 February 1937, the ministry of defence decided on 10 April 1937, confirmed by the Conseil Consultatif de l'Armement in May 1937, to place a second order of fifty vehicles. This was done in the context of an ongoing discussion whether or not to proceed with the production of the expensive and obsolescent Char B1; continued production of the Char D2 kept all options open. Renault gave the assurance that his factory could manufacture two hundred units per year. During 1937 the first reports regarding the operational use of the type were rather alarming in that they clearly indicated an unreliable vehicle. Despite hesitations the order was actually made in June 1938. However, production at first failed to materialise due to severe financial and social problems with Renault. This aggravated the reliability problems for the existing vehicles as also insufficient spare parts were manufactured.At the same time the production process of another Renault tank type, the AMC 35, was faltering. Interest in the AMC 35 project was more or less kept alive by a foreign buyer, i.c. Belgium, and something similar happened for the Char D2. In August 1938 a commission arrived from Poland, investigating whether the Char D2 could be produced for that country, using an export credit of a billion franc that Poland had obtained in September 1936 to procure French weaponry. Initially Poland had favoured the more modern SOMUA S35 but sales of that type had been denied, priority being given to the needs of the French army. Negotiations, complicated by issues of technology transfer and a possible licence production, failed at first; however, early 1939 directing the second production batch to Poland was considered, but this was eventually forbidden by the French supreme commander Maurice Gamelin. He had learned that the condition of the first fifty vehicles was so poor that the best way to keep the single battalion equipped with the type operational was a complete replacement of the older with the newer vehicles. The first batch could then be rebuilt into flamethrowers.
After the start of the Second World War Édouard Daladier on 27 September 1939 decided that the type would not be among the few chosen for further mass production but that the second order would nevertheless have to be completed to indeed allow a replacement; a first batch of fifteen flamethrowers was ordered. This also implied that funds were made available to recommence manufacture at Renault. Plans foresaw a delivery of five vehicles in February 1940, eight in March and then ten units each month until the last seven would be delivered in July. In fact in February six vehicles were produced, in March seventeen; six in April; thirteen in May and eight in June. Actual deliveries to the Army again differed: five on 27 March; eight on 22 April; ten on 6 May; twelve on 25 May and finally two on 6 June. Of the remainder of thirteen vehicles it is unknown whether they were ever handed to the forces: they were sent south when the Renault factory had to be evacuated on 12 June.
The second production series featured several improvements. The most important of these was the fitting of the APX 4 turret, equipped with the longer SA 35 gun, which had a far better antitank-capacity, with about twice the original armour penetration, mainly due to a longer cartridge. Due to the longer rounds the ammunition load decreased to 108 rounds. The new turret also had PPLR X 160 episcopes instead of Chrétien diascopes and was fitted with a S 190 G attachment point on the roof above the back hatch, to use the reserve machine gun as an AA-weapon. Analogous to the Char B1 bis designation for the similarly improved second Char B1 version, some internal unit documents in 1940 began to refer to the second series as the "Char D2 bis", but this was never an official name.
Other changes included: an improved greasing system; reinforced ball bearings for the road wheels; a different form for the idler and sprocket to reduce the chance that tracks would be thrown; shorter mudguards; a thinner antenna; a new Vertex distributor and a Vlet starter engine using compressed air to reduce the demand on the battery.