Saturday 31 December 2016

Char B: On France's Backburner

On May 13th, 1924, a demonstration of medium tanks built according to the Char de bataille program took place in Rueil-Malmaison. FAMH, FCM, Renault, and Schneider each built a prototype. The plan was to pick the most successful design and split up the contract for 120 tanks between the companies. However, it turned out that none of the tanks completely satisfied requirements of the military. As a result, General Estienne, the originator of the Char B program, was forced to create new requirements in March of 1925 for an improved tank which would use the most successful technical solutions from its predecessors.

Last One Out

Tasked by the military with coordinating the work on the Char B, Renault presented a model of the prototype for approval in 1926. The improved tank was created while working closely with Schneider, which designed a modernized turret for the tank. The Renault-Schneider duo was the main driving force behind the new design. Another participant was the STCC (section technique des chars de combat). With their aid, Schneider's engineers improved the turret. Maurice Lavirotte, an employee of Ateliers de Puteaux (APX) was put in charge of the work on the Char B. Formally, APX had nothing to do with the Char B, and only started working on the project in the 1930s, but in practice, the company had significant influence on the development of the new tank.

Full sized model of the reworked Char B, 1926.

Even as a model, the tank was significantly different compared to the experimental tanks. Even though the design was based on the SRA and SRB, only the overall layout remained. Compared to its predecessors, the new Char B was 40 cm longer, but that was only the beginning of its metamorphosis.

The suspension used in the prototypes was too bulky, which resulted in a lot of unused space between the side of the tank and the spaced armour. The FCM prototype was much more reasonable in this regard. The volume taken up by the suspension was decreased, and the tracks now wrapped around the whole hull. The decision was correct, as the newly formed bustles on the sides went to good use.

The drive sprockets increased in size. The driver's station also noticeably changed. Like in the FAMH prototype, he was placed in a cabin, which improved his visibility. In addition to the cannon, a machinegun was installed in the hull, and the crew was increased to 4 men. The fourth crew member was a radio operator.

The first Char B1 prototype, copy of a factory blueprint.

The model commission approved the project. On March 18th, 1927, contracts were signed with Renault, FAMH, and FCM to produce prototypes. Schneider was not included in the list, but it's hard to think of the company as a victim of a conspiracy. Schneider was awarded the contract for making the hulls and turrets, hardly a loss.

As for FAMH, aside from one prototype, it was tasked with building two 75 mm guns. The third was built at Schneider. In addition, the STCC and Schneider were working on a modernized version of the tank, indexed Char B1. This had to do with the fact that the tank, codenamed Tracteur 30, was clearly not going to fit into the weight requirement. The initial range of 19-22 tons did not accurately reflect reality. According to calculations, the mass of the tank would be at least 23 tons, and in practice it approached 25 tons. The Char B1 was almost twice as heavy as Estienne's initial requirements for a battle tank.

Suspension elements of the Char B1. Despite its visual similarity to "rhombus" tanks, the Char B1 had a different and rather complicated suspension.

Renault was the first to complete a Char B1 prototype. In March of 1929, tank number 001 began factory trials. It looked very much like the model, but with corrections for the tank's growth. Instead of a 180 hp Renault engine, it used a more powerful 6 cylinder engine with aircraft roots, like its predecessor, but a power of 250 hp.

The suspension, which was shown in very general terms on the model, demands closer attention. It was designed at FCM's design bureau under the supervision of engineer Burdeaux. The new suspension had a lot in common with the suspension designed for the FCM 2C. In total, the tank had 16 road wheels per side. 3 front ones and 1 rear one had individual leaf springs. The rest were combined into bogeys (3 groups of 4 wheels), and vertical coil springs were used as the suspension element.

The suspension was accessible from inside the tank, which made it easier to service in battle. The travel of the suspension was not large, but it was enough for a tank that was supposed to be used on the "moon landscape" of trench warfare. The track links were a further development of the design used on the SRB.

Char B1 001 on trials, 1932. By then, it was already using the ST3 turret.

After finishing the first stage of factory trials, the experimental Char B1 drove from Rueil-Malmaison to Bourget. The tank made the 250 km trip in a day, with an average speed of 16.5 kph. It was the first French tank that could independently drive such a distance without serious breakdowns.

Trials continued until April of 1930. Various improvements were tested, changing the tank visually. The military was generally satisfied with their new tank, but problems were recorded with the insufficiently robust NAEDER turning mechanism.

Closeup of the turret and 75 mm gun.

Work on building two more experimental vehicles was postponed, as they included the new experience collected during trials of tank 001. In the meantime, FAMH let go of the contract for building a second tank. As a result, tank #102 was also built by Renault and was finished in 1931. As for FCM, nothing happened to contract #215 D/L, and the vehicle was complete in 1931. Initially, it had a dummy turret.

Awaiting Disarmament

Trials of the Char B1 prototypes were conducted in an uncertain situation. A conflict erupted between Estienne and the infantry, which grew into a serious confrontation. This was due to the fact that the infantry had its own vision of an infantry support tank.

Estienne proposed a large tank with serious armour and armament which would not be produced in large volumes like the Renault FT. The infantry had different opinions. In 1928, the NC-3 light tank began trials, which eventually became the Char D1. It was not as large or well armoured as the Char B1, but it was much lighter and, potentially, a lot more could be built. Its 47 mm gun, which appeared at the same time as the ST1 and ST2 turrets, was enough for the task of direct infantry support.

The tank's initial turret was later returned.

Another factor that hammered a wedge between Estienne and the infantry was the development timeline. By the time the third Char B1 prototype was finished, the Char B program was already running for seven years. Time passed, and with it, requirements for the battle tank grew.

In October of 1930, a program began to develop a new generation of tanks. Which led to new departures from the initial Char B concept by January of 1932. The first tank, Char B2, was supposed to have a long 75 mm gun, 50 mm of armour, and its mass would increase to 35.5 tons. The 45 ton Char B3 would have a 6 man crew, a 75 mm gun like the Char B1, and a long barreled 47 mm gun.

Finally, Estienne decided to revive the FCM 2C concept, but this time as a "stopping tank" (Char d'arrêt). Work on this design began in 1928. In 1932, they resulted in the Char BB project. The 60 ton tank had a pair of 75 mm long barreled guns, 60 mm of armour, and an 8 man crew.

It's unlikely that any of this made the infantry command happy, as they needed immediate replacement for thousands of obsolete Renault FT tanks instead of long term plans.

Tank #103 with a dummy turret.

Finally, another factor came into play, which directly influenced the French tank program. A disarmament conference began on February 2nd, 1932, in Geneva, initiated by the League of Nations, which became concerned about a new armament race in Europe. Even though the results were quite contradictory, it had some impact on potential designs.

The Char BB was the first victim of the conference, as it fell under the imposed limits. The same fate awaited the Char B2 and Char B3, as further limits on the mass of tanks were expected. For this reason, work did not progress pas the tactical-technical requirement pase.

The initial proposition by the French to limit the mass of tanks at 92 tons alerted the Germans. The outcome of this requirement was the appearance of "heavy tank D" in the German "Tanks" encyclopedia: a 92 ton tank with a 15 man crew, one 155 mm howitzer, one 105 mm howitzer, and two 75 mm guns.

While debates in Geneva raged on, the trials of Char B1 prototypes continued. Due to complaints about the NAEDER system, an experiment was performed with a hydraulic gearbox designed by the Swiss Winterthur company (modern day RENK-MAAG). It's possible that the French received information about it from the British, who used the same gearbox on the A1E1 Independent tank.

Tank 103 also used a 180 hp diesel engine from the Swiss company Sulzer Ltd., which was also located in Winterthur. Trials of this engine were unsuccessful. It never achieved its nominal power, and strong vibrations were observed.

The French Clerget company also proposed a 180 hp diesel, but its trials were also unsatisfactory. In any case, this was good experience for FCM, which was later applied during the design of the FCM 36.

Tank #103 during mobility trials.

An experimental unit was created in August-October of 1931 to test the new tanks. Initially, it was based in Rueil-Malmaison. The tanks' average speed was 12 kph, and their maximum speed was 22 kph, higher than that of the Char D1. Later, the unit was transferred to a military base next to Mourmelon-le-Grand. 

The tanks were constantly improved during military trials. The suspension was altered, a pneumatic suspension and various kinds of gearboxes were tested. Radios of various types were tested as well. Tank #001, later renumbered to #101, served as a testbed for ST1 and ST3 turrets.

Experimenting with radios on the new tanks. Another type of antenna went into mass production.

Even though the tanks showed growing pains, the conclusion was made by the end of 1932 that the tanks are satisfactory for completing tasks expected of them. Around this time, the first reviews of the Char D1 began arriving from the military, and they were not particularly flattering. The Renault UZ, later renamed to Char D2, entered trials in 1932. Its turret was used on the Char B1.

It was expected that a contract for the production of seven Char B1 tanks would be signed in late 1932, but a new phase of disarmament talks began in Geneva. The French military waited. Back in 1930, during the London conference, the issue of limiting the mass of tanks to 25 tons was raised. Even though the Char B1 gained weight during all these conversions, it still fit into this limit.

In February of 1932, the rules of the game changed. British Prime Minister James Ramsey MacDonald proposed limiting field artillery to 105 mm and the mass of tanks to 16 tons. This was no accident, as that was the weight of the British three-turreted Medium Tank Mk.III. 

If the conference accepted the British proposal, it would have been the end of the Char B1, and the Char D2 would have taken its place. However, the debates achieved nothing, and Germany left the commission on October 23rd, 1933. One thing was obvious: there would be no weight limit.

Having the choice between a more or less ready Char B1 and the problematic Char D2, which they were feverishly trying to find an engine for at the end of 1933, the French infantry opted for Estienne's tank. This was a serious mistake, since the Char B1 was incapable of being produced in sufficient numbers for several reasons. However, at the time, this seemed like a good decision.

Technically in Production

On March 13th, 1934, almost 13 years after the start of the Char B program (and 17 years after the beginning of work on the Schneider CA3 tank), contract #30 D/P was signed with Renault to produce seven Char B1 tanks. A decision was also made to upgrade tanks #102 and #103 to mass production standards. Tank #102 received the proper name Amorique, and tank #103 became Lorraine.

Even before the beginning of production, in December of 1933, one noticeable change was made to the Char B1. As a result of using the Char D1 and testing the Char D2, it was clear that the ST1 and ST2 turrets were too small. A decision was made to use the APX 1 turret designed by Ateliers de Puteaux (APX). The turret ring diameter was increased to 1022 mm, and the turret became roomier.

However, it was not possible to get rid of the main issue. The initial idea of a machinegun turret with the turret ring diameter of the Renault FT that the Char B and Char D shared left no room for a two man turret.

Initial production tanks had no 75 mm guns. They were installed later.

On December 26th, 1934, contract #1029 D/P was signed with Renault to produce another 20 Char B1 tanks. The company was overloaded with orders, as production of the Char D1 was still on, and a contract for 50 Char D2 was signed on December 24th. Work on the Renault ZM, which would later become the Renault R35, was also going full throttle, and that's not including work on light reconnaissance tanks for the cavalry.

It's not surprising that tank #104 (later given the name Verdun) was completed only in December of 1935. Contract #30 D/P was only satisfied by Renault in may of 1936, and the tanks came with no 75 mm guns (they were only installed later), and there were not enough turrets for every tank.

Renault started making good on its next contract, #1029 D/P, on March 27th, 1936, when tank #111 "Dunkerque" was accepted by the customer. The last tank under this contract was shipped on January 5th, 1937, with 6 tanks produced at FCM.

Renault's financial difficulties created additional problems in 1936. The French government had to take extreme measures: in late 1936, Renault's tank production in Issy-les-Moulineaux was nationalized. A new company was founded in its place:  Ateliers de construction d'Issy-les-Moulineaux (AMX for short). Renault retained the rights to produce the Char B1, but in a different place.

Similar changes happened with APX in 1936. The company's factory in Rueil-Malmaison was nationalized. The factory was renamed Ateliers de construction de Rueil (ARL), and Maurice Lavirotte was appointed as its chief designer.

Tank #130 "Ile de France", 1936. After exercises, the idea of trailers was rejected.

The next contract, #1891 D/P, signed on October 8th, 1936, fell to FCM due to all the commotion at Renault. The first tank under this contract (#131 Touraine) was delivered on June 9th, 1937, and the last (#135 Morvan) left the factory on July 30th. In total, out of 32 Char B1 tanks, plus two prototypes modernized to production standards, 11 were built at FCM.

Gradually, the price of the tank decreased, but was still very high. Tanks from the latter batches cost 1,218,000 francs apiece. To compare, the Char D2 cost 610.000 francs. At the moment of its creation, the Char B1 was the most expensive tank, equal to the cost of two British Infantry Tanks Mk.II at the start of their production.

511th Tank Regiment lined up for parade. The first B1 tanks were sent to this unit.

The completed tanks were sent to the 511th Tank Regiment, created on March 12th, 1936, out of the 51st Heavy Tank Battalion. The first Char B1 tanks were sent to the unit even before the reform, in early 1936. The regiment's new headquarters were at Verdun.

The first exercises held with these tanks showed that the idea of a trailer was not the best. For this reason, late production Char B1 tanks were built without a trailer hook. It was decided that a special vehicle would be used instead, which gave birth to the Lorraine 37L tractor.

All 34 tanks were sent to the 511th Tank Regiment. The first production tank, #104, was used by the commander, Colonel Bruno. All tanks received names of French towns and provinces.

Tank #112 Mulhouse from 3rd company, 37th BCC. The tank has the new 47 mm SA 35 gun. The tank suffered a typical fate for a Char B1: it was abandoned near Orleans on June 15th, 1940.

On August 27th, 1939, the 511th Tank Regiment was reformed once more. Its Char B1 tanks were included in the 37th Battle Tank Battalion (BCC). The process of modernization began around the same time. Like Char D2 tanks, these tanks received long barreled 47 mm SA 35 guns. After these changes, Char B1 tanks became almost identical to the late Char B1 bis. It is still possible to distinguish between them due to different observation devices in the turret.

The tanks needed major repairs. In the process, the tanks were spread out across different units. By the start of the war, there were no longer any Char B1 tanks in the 37th battalion. They returned only on May 16th (tanks ##104, 112, 122, 127, 132). 12 tanks ended up in the 347th Independent Tank Company (CACC), formed on May 17th, 1940.

After long journeys along frontline roads, only 3 tanks remained by June 3rd. Another 3 apiece tanks were located in the 106th and 108th training battalions (106th BIC and 108th BIC). 11 tanks were in Mourmelon. The fate of the first mass produced Char B tanks was no better than that of the Char D2. Some were destroyed in battle, but most were captured by the Germans.

Flamm.Pz.B2 740(f) made from a Char B1. Western Ukraine, June of 1941.

Despite the differences between the captured B1 and B1 bis tanks, the Germans gave them one index: Pz.Kpfw. B2 740 (f). Some captured tanks were converted into flamethrower Flamm.Pz.B2 740 (f) tanks. Among them was tank #103, Lorraine.

The tank in the 347th CACC became the victim of the marathon along French roads in late May of 1940. After repairs, the Germans converted it into a Flamm.Pz.B2 740 (f). On May 31st, 1941, the tank was included in the 102nd Flamethrower Tank Battalion (Panzer-Abt. (F) 102), where it received the tactical number 131. This wasn't the only instance of a Char B1 being converted into a flamethrower tank. At least two more (tactical numbers 113 and 233) used the old chassis. As for tank #131, it participated in the assault on the "Velki Dzyal" stronghold in the Rava-Russkiy fortification region on the western border of the USSR. During the attack, it was hit by a cannon installed in a bunker and burned up.

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