Renault Char d’Assaut 18hp – Renault FT Development

France (1915-1917)
Light Tank – Around 3,500 Ordered

When the Republic of France entered World War 1 on 3rd August 1914 against the German Empire, few could have had any concept of the scale and duration of the war which was to follow. Having already fought the nascent German Empire in 1870-1871 and lost the territory of Alsace-Lorraine in a humiliating defeat, France was determined not to repeat its failures, yet entered WW1 unprepared for a new type of warfare dominated by artillery and rapid-fire machine guns. Just as other nations soon found, the men of their respective armies, regardless of personal heroism, were no match for a well-prepared defense or machine gun fire. Machines were to be a key to victory, new armored machines carrying guns to meet the enemy and, to this end, France developed a tank which was to shape their future designs for many years and become an icon of WW1 – the Renault FT.

Background

The Republic of France was to suffer appalling casualties in WW1. The Western Front, large swaths of which cut through Eastern and Northern France, was the scene of some of the bloodiest fighting ever seen in Europe and was brutal grinding butchery for four years from 1914 until 1918.

Despite numerous assaults by the British, French, and Germans on the Western Front, neither side could gain an advantage, and the war descended into a static war of attrition, with troops having to shelter below ground from the murderous effects of artillery and machine gun fire. The industrialization of Europe had created the situation where artillery and machine guns could bring warfare to a standstill and the military tactics of the belligerents had not adequately kept pace with technology.

Just as modern technology and industrialization had created the circumstances for the static war, they also held out the prospect of a solution for it as well. Automobiles and aircraft were in their infancy, but were rapidly turned to war uses and armored cars had actually been in development in many nations prior to the war. It is no surprise then that, with the slaughter taking place in Europe between the Great Powers, as armored cars could not traverse the shattered ground, tracked vehicles were considered by Britain, France, and Italy (suffering its own stagnant warfare on its northern front against Austria-Hungary) all around the same time.

Tracks to get over the broken ground would then need armor to protect the crew, and weapons to bring the fight to the enemy. The concept of what was to become the tank was an inevitability, but these allied powers had little in the way of coordination in the early days of the war, and each ran their own programs with varying degrees of success.

A French Solution

Unlike the British, who by 1915 had abandoned the Holt track system, and by the end of the year abandoned other ‘low-slung’ types of track in favor of an ‘all-round’ system, the French were still looking at the Holt system for their own designs. There was some parallel development in France, with some work on machines such as the Schneider CA1 and St.Chamond, but one man stood out with a different view, that of a smaller machine better suited to the conditions on the front lines.

The man behind all of this was the French ‘Father of the Tanks’ (French: ‘Père des chars’), Jean Baptiste Eugene Estienne (1860 – 1936). With an aptitude for mathematics and science, he had joined the French Army in 1883, becoming an artillery officer. By the start of WW1, Estienne was a Colonel commanding the 22nd Artillery Regiment in combat.

With a first-hand experience of the power of modern weapons, such as his own artillery, but also witnessing the devastation from machine guns, he rapidly saw the need for some kind of protective shield. By the middle of 1915 (at a time when the British were already working on what was to become Little Willie), Col. Estienne learned of a tracked barbed-wire cutter based on the Holt chassis and developed by Eugene Brille of the Schneider Company.

It was not much of a logical extension for Col. Estienne to consider this as a suitable vehicle on which to mount some armor. His efforts failed though until December 1915, when he finally convinced Marshal Joseph Jacques Cesaire Joffre (1852 – 1931) of the validity of his idea.

Unknown to Col. Estienne at the time was that Schneider had already been developing its own vehicle with exactly the ideas he had in mind; armor and a gun on the Holt chassis. That tank became the Schneider CA-1 and Col. Estienne witnessed trials of that vehicle on 9th December 1915. The Schneider design had some very serious shortcomings, not least of which was the mounting of the main gun in a peculiar fashion on the side of the machine, seriously limiting its combat potential.

The engineering-orientated mind of Col. Estienne must have been triggered into action by this experience, as on 21st December 1915 (the day the Schneider CA-1 was authorized for production), he reached out to the famous industrialist Louis Renault (1877 – 1944) with his own ideas for a better vehicle – one designed from scratch to do the job rather than just a modified tractor. Monsieur Renault was, at first, reluctant to embark on building a tank, but by the middle of July 1916, he confirmed to Col. Estienne that he was indeed working on a light tank.

The war conditions for France had not improved since 1914, but waiting until the middle of 1916 had now put France well behind Great Britain in terms of tank development. Lagging behind, but now aware of British developments, the French actually tried to convince the British to hold off on using their own tanks for the first time until they were ready with theirs. No doubt, it was a fine idea to have a coordinated approach, but the slaughter underway each day was not abating and the British were anxious to try and break the stalemate which was also costing them so dearly.

Following the British use of tanks in September 1916, the French were now under no illusions about the true potential of these new weapons and, on 30th September 1916, Colonel Estienne, as the most senior French officer with the knowledge, interest, and experience in such matters, was appointed as Commander of the newly formed French armored corps, known as the ‘Artillerie Speciale’ (English: Special Artillery).

Conception and Development

The idea for a tracked tank had first been brought to Louis Renault’s attention by Colonel Estienne back in December 1915, but he had at first been reluctant to postpone or divert production away from other military work for a new and unproven weapon. By the summer of 1916, however, this view had changed, probably as a result of his factory being subcontracted to produce parts for other firm’s tank designs, although he had been doing some preliminary work on a tank design nonetheless. M. Renault confirmed to Col. Estienne in July that year that he was working on a light tank design, although how much of Col. Etienne’s ideas had to that point been absorbed or used by M. Renault is debatable. What is known though, is that Col. Estienne had been unimpressed by the ‘big box’ tanks and foresaw instead a mass of smaller, light tanks acting like a swarm of bees, overwhelming the enemy with a rapid advance, and multiple weapons delivering fire from all quarters during an advance. The conversation on 21st December 1915 between Col. Estienne and M. Renault showed that what was wanted was a tank of not more than 4 tonnes in weight, a two man crew, a top speed of up to 12 km/h, and a machine gun in a turret on top. M. Renault agreed to produce a wooden mock-up of such a design by October 1916.

This new tank would have to be mechanically simple to ease demands of production, which was already at full stretch for the war effort, be constructed by relatively unskilled labor, as most of the skilled workforce was now in uniform fighting, and be cost-effective. The Army could not afford enormous and expensive vehicles that had so far proven to be somewhat unremarkable, like the Schneider CA-1 and the enormous St. Chamond. Smaller, cheaper vehicles, and lots of them were the order of the day.

M. Renault was director of the Société des Automobiles Renault (Renault Automobile Company), but other key individuals at the firm and connected to it were involved in aspects of the design, such as M. Rodolphe Ernst Metzmaier (industrial designer), and M. Charles Edmond Serre. They were to fulfill Estienne’s vision of small fast tanks within their own manufacturing capabilities and what they developed was to become one of the most famous tank designs of all time, the Renault FT.

“L’audace, l’audace, toujours l’audace!” – A Bold Design

In order to be mass produced, this new tank would have to seize upon the enemy quickly and boldly destroy it with machine gun fire. To do this, it was shorter, narrower, and lower than the CA-1 or its huge cousin, the St. Chamond. Smaller would mean less space for the crew and this was reduced to the bare minimum – just 2 men. One man would drive and the other would command the tank and operate the weapons.

Using a single weapon with all-round fire in a turret was not a new idea by any means, and was already in widespread use on armored cars, and even on Little Willie and some earlier British designs, although the British later switched to side-mounted guns instead. The key advantage of a turret, as used for this little French tank, was that it concentrated firepower in one place, for one man, which allowed the tank to remain small and yet carry useful firepower for the assault. A turret was quite simply the only practical solution to the problem of providing fire to all sides on a light tank. This was realized by the British for their own ‘light’ tank, the Medium Mark A Whippet, which started development in December 1916 and which, in its early form, was the ‘Chaser’ and had a single turret for firepower. Whereas that turret was abandoned in favor of multiple machine guns all round in a large casemate, the Renault was too small for that to be an option, so it was a turret or nothing.

With the driver placed in the front, the commander/gunner sat behind him to operate the turret and weapon, and the engine at the back, the Renault FT is seen by many as being the first ‘modern tank’ although such comparisons are superficial at best. The most important part of this Renault tank is often ignored by historians and was, in fact, the separation of the engine from the crew. The British tanks, for example, did not do this vital safety-step until the Medium Mark B in 1918, and neither the French Schneider CA-1 nor the St.Chamond did this either. The bulkhead protected the crew from the stifling heat and fumes of the engine and, perhaps more importantly, from potential engine fires.

M. Renault finished his wooden mock-up on schedule in October 1916 and showed it to Col. Estienne. This design set the basic layout for the vehicle over its life, although each part was subject to changes at one point or another. For this wooden mock-up, the turret was nothing more than a simple cylinder with the only armament. Stood inside the tank, with his head and shoulders inside the turret, was the commander/gunner who could use a hatch in the turret to climb in and out. The driver, however, sat at the front, would have to use a hatch on the front deck of the tank, a very dangerous prospect for him if he had to get out facing enemy fire.

Perhaps the biggest hurdle to the development of the FT was not the relative merits or deficiencies of the design, but the French military mindset. For a big battle, it was logical that a big assault, a big gun, or a big weapon was the solution and the concept of small, light tanks was perhaps incongruous in the face of the large British tanks and the no less huge St. Chamond.

The prototype was tested and, despite some reservations, was accepted for service in May 1917, when Marshal Henri Philippe Pétain (1856 – 1951) replaced General Robert Georges Nivelle (1856 – 1924) as Commander-in-Chief of the French Army following the disastrous Nivelle Offensive and French Army mutinies. Marshal Pétain was an advocate for the use of tanks, supportive of Estienne, but also with an eye not just to its potential as a weapon but also as a morale booster for the war-weary infantry who were bearing the brunt of the fighting. Later, he was to order that all of the trucks carrying these tanks to the frontline have written in large characters on their backplate “Le meilleur ami de l’infanterie” (English: ‘infantry’s best friend’).

Brigadier-General Leon Augustin Mourret (1849-1933) though, Director General of the Motor Services, was reluctant to adopt the Renault design which, at the time, was being developed under the working title of char mitrailleur (English: machine gun vehicle). He was likely conscious of interfering with the production of other equipment such as trucks, tractors, and artillery.

A new mock-up char mitrailleur was presented on 30th December 1916 to the Consultative Committee of the Assault Artillery. Gen. Mourret remained unimpressed, however, despite no longer being the Minister in charge, complaining the vehicle was too light, with the center of gravity too far back, making it unstable, and that there was inadequate ventilation for the crew. Other suggestions included a wider hull and turret, and storage for up to 10,000 rounds of machine gun ammunition (‘normal’ carriage was just 1,820 rounds).

The basic design from October 1916 had been set but there were still deficiencies. The cylindrical turret for the commander/gunner, who had to do both jobs simultaneously, was only fitted with crude vision slits making for very limited observation of the ground around the tank. The body of the tank was a large riveted box with a bulbous back end housing the engine. At the back of this body was a small starting handle for the engine and there was a small air intake on top.

The suspension changed little from the prototype to production, although the vertical spring in the center of the suspension which connected to the arm holding the return rollers was removed for production as it had little value.

The arrangements of the body and turret were not ideal and wasted space and weight, both of which were critical. By December 1916, significant modifications to both had been made. The hull’s back was cut much shorter, saving a lot of weight, and the small cylindrical turret was replaced with a much wider hexagonal one with a cross-shaped vision slit in each face. The turret also overhung the side of the hull, necessitating small flanges to be attached to the hull to cover the bottom of the turret where it projected. All of the plates used in this revised design were flat and to be made by riveting to a steel frame inside the vehicle.

Some of the suggestions from the December 1916 examination were acceptable to the design team, but others were clearly impractical. The Consultative Committee of the Assault Artillery then voted on production; the vote was seven-to-three in favor of production and orders for 100 char mitrailleurs followed. That order was increased in February 1917 to 150 vehicles, although Col. Estienne had been pressing for orders for 1,000.

The FT-17 That is Not

It is important to note that the name ‘FT’ was never an abbreviation or acronym, despite numerous books and websites claiming explanations for the initials including ‘Faible Tonnage’ (English: ‘low tonnage’ – ‘light weight’) or ‘Franchisseur de Tranchées’ (English: ‘trench crosser’). The name ‘FT’ was none of those, it was just a factory code for this char mitrailleur, nothing more, nothing less. All the Renault tank products were issued with a two letter code serving to identify and differentiate them. FT simply followed FS, and would, in turn be followed by an FU (which was later used for a heavy Renault lorry), then FV.

The Renault FT is also often referred to as the ‘FT17’ or ‘FT-17’, although this specific naming was never acknowledged by Renault or any official working on the project. The ‘17’, of course, was in connection to the year 1917, as it was customary for many French weapons of the time creating the ‘char leger Renault FT modèle 1917’ (English: Renault Fast Tank Model 1917). The ‘FT-17’ designation though, was only later referred to, after the war. For the duration of WW1, it was simply the Renault FT for convenience.

Prototype

A single prototype vehicle for this new version of the FT was delivered in January 1917 and performed first trials at Renault’s factory at Boulogne-Billancourt, before being sent by Col. Estienne to the Artillerie spéciale (English: Special Artillery) proving grounds at Champlieu, North-East of Paris, for final corrections before its official make or break trials in April that year.

If getting an order for a prototype and small production for his light tank idea was a win, then in April 1917, even before the trials, Col. Estienne was triumphant. The Consultative Committee of the Assault Artillery was on his side and voted in favor of his plans for production of 1,000 examples. This triumph was further crowned by General Nivelle, who was not an opponent of tank production, was now a convert to armored warfare and supported this production.

Official trials took place at Marly, South-East of Lille, between 21st and 22nd April 1917. Here, during comparative trials against the Schneider CA-1 and St.Chamond tanks, the diminutive FT was shown to be superior. Perhaps buoyed by his success in winning over General Nivelle and the proof of concept beating any other tank the French had, Col. Estienne then suggested that this machine gun armed tank be fitted with a small 37 mm gun creating a ‘char canon’. It had never been intended to carry anything other than a machine gun until this point, but he felt that a version of the 37 mm modèle 16TR infantry cannon could be made to fit and would provide some useful support to infantry in attacking enemy defences. A machine gun, after all, was almost useless against an enemy bunker, but a small gun could fire explosive shells right where they were needed instead of relying on field artillery behind the assault. There was insufficient space for both a cannon and a machine gun. But, as these vehicles were to be used in groups, they would be able to provide complementary fire for each other, with the char canon taking out the strongpoints and the ‘char mitrailleur’ taking out the infantry.

Reservations

General Nivelle might have been converted to the value of the tank, but M. Albert Thomas was not to be convinced. The small space inside the turret effectively limited it to a commander not more than 1.68 m tall (5’6”). This, combined with concerns over the instability of the vehicle, the ventilation for the crew, inadequate ammunition capacity, and the difficulty of one man commanding and operating the gun, led to him suggesting an additional crew member be added to operate the main armament. The addition of a third crew-member would mean a total redesign of the vehicle to accommodate him, but would in fairness have solved a problem that was to plague French tanks for a generation, the tiny one-man turret.

Regardless of his concerns, right or wrong, it was too late. General Nivelle’s offensive on the Chemin-des-Dames was an utter failure, with great loss of life, and further delays to a tank program were no longer acceptable. M. Thomas though, left on an overseas trip, and in his absence, Col. Estienne simply worked around him. He demonstrated the tank for officers from the disastrous Chemin-des-Dames offensive, including those who had fought with the Schneider and St.Chamond tanks in what was France’s first use of tanks – they were convinced. Their insistence and the political pressure of a failure to break the stalemate on the Western Front now persuaded even the reluctant General Mourret that they were needed urgently, and he overruled M. Thomas’ order. The original order for 1,000 vehicles was replaced with a new order for 1,150 vehicles, consisting of 500 of the original char mitrailleur armed with the 8 mm Hotchkiss machine gun and 650 of the new char canon fitted with the 37 mm gun.

Pétain, the advocate

Marshal Pétain, himself an artillery officer, knew Colonel Estienne and had, in general terms, agreed on the need for tanks and that small, fast tanks could overwhelm an enemy unlike the large and slow Schneider CA-1 and St. Chamond. In a brutal war of attrition, production played a part too, and the tiny FT had a small manufacturing footprint. Five FTs could be built for every heavy tank and those heavy tanks were not armored sufficiently to stop German artillery fire. Instead of armor then, these small tanks would rely on their small size and good mobility to avoid enemy fire. Pétain did not need much additional convincing post-Chemin-des-Dames and increased the order from 1,150 to 3,500 vehicles instead. The design undoubtedly had significant flaws but it had a single massive advantage over every other design available – it worked. Rather than wait on new and improved design Pétain made use of what he had, a working design, and one intended for a new offensive in Spring 1918.

To smooth out production, the hurdle that was M. Albert Thomas was removed too, replaced in September 1917 by the Under Secretary of State for Artillery and Munitions, industrialist M. Louis Loucheur (1872 – 1933). Nothing was going to get in the way of Pétain’s new tank. So when, shortly after placing this order, it was found that Renault would not be able to produce all these vehicles itself in time, Renault waved any patent rights issues, allowing production to go to other factories. Contracts were eventually issued to Berliet, Somua, and Delaunay-Belleville as well as consideration of production outside France in Italy and the United States in order to produce the numbers demanded.

Conclusion

The development phase of the Renault FT, one of the most identifiable and famous tanks of all time, had concluded. The vehicle would undergo significant modifications and trials with various nations and see action beyond WW1 in many theatres. It was not a perfect tank by any means, the tiny one man turret, the front access for the driver, the lack of a radio, and the relatively weak armament would plague the vehicle and its many variants, but the design was to prove the most successful French tank of WW1 even if it nearly never happened at all.

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Illustration of the 1916 design of the FT produced by Yuvnashva Sharma, funded by our Patreon campaign.

Sources

Renault. (1917). Renault Char d’Assault 18hp.
Canon de 37 SA pour Chars Légers 1918
Lt. Goutay. (1920). Manuel pratique du Char Renault
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War Office. (1931). Instruction sur l’Armement et le Feu dans les Chars Légers
War Office. (1935). Instruction sur l’Armement et le tir dans les unités de Chars Légers
Bruché, Col. (1937). Manuel d’Instruction pour les Unités de Chars Légers – Canon de 37 SA –
Gale, T. (2013). The French Army’s Tank Force and Armoured Warfare in the Great War. Ashgate Press, England
Vauvallier, F. (2014). The Encyclopedia of French Tanks and Armoured Fighting Vehicles 1914-1940. Histoire and Collections Publishing, France
Zaloga, S. (2010). French Tanks of WW1. Osprey Publishing

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