Category: WW2 French Prototypes

Batignolles-Châtillon Automitrailleuse à vapeur

Post author By Harold Biondo
Post date July 19, 2023
2 Comments on Batignolles-Châtillon Automitrailleuse à vapeur

France (1937~1940)
Steam-Powered Artillery Tractor? – 1 Built

The country of France is remarkable for having produced some of the oddest and most creative armored vehicles throughout history. Seemingly never content to take the conventional route, France’s tank designers always attempted to innovate in whatever they designed. No company better exemplifies this than La Compagnie générale de Construction de locomotives, or General Company for the Construction of Locomotives, abbreviated as CGCL and better known as Batignolles-Châtillon, after the two companies that merged to form it.

Full of Hot Air

Batignolles-Châtillon was a steam locomotive manufacturer first and foremost. Its first venture into the world of armored vehicles was with a response to the 1933 requirement by the French military for a light infantry tank to replace the Renault FT. Batignolles-Châtillon’s submission, a design which never received a name, was one of five selected to proceed to the prototype stage. The sole vehicle was completed in 1935.

The Batignolles-Châtillon Light Infantry Tank. Source

The construction of the hull of the light tank made judicious use of sloped armor and riveting. The driver was provided with large glass vision ports and the entrance to his position was a set of doors located at the center of the hull front. The tracks were Kégresse type rubber bands. The original suspension design, a spindly leaf spring setup with seven roadwheels and eight tiny return rollers, was replaced after initial trials with a much more robust combination of horizontal and vertical springs, supporting three pairs of two roadwheels and four return rollers.

The Batignolles-Châtillon Light Infantry Tank with revised suspension design. Source

Although it was a competent design for a first-time tank builder, Batignolles-Châtillon’s light infantry tank was not chosen for production, due to being underpowered and unreliable. The company continued to work on armored vehicles through the rest of the pre-war period, designing a set of amphibious tanks that, like their light tank, did not go anywhere. These three projects are usually regarded as being all of the tanks developed by Batignolles-Châtillon until after World War II, outside of which there is little in the historical record.

Fire, Smoke, and Steam

The two photographs of the Batignolles-Châtillon Automitrailleuse à vapeur. Source: Author’s Collection

In November 2020, two photographs came up for sale on ebay.de which showed a heretofore unknown vehicle being loaded onto a trailer by German soldiers. Its construction appeared to be a strange contradiction of modern and old-fashioned parts. A highly sloped frontal plate, sloped and reverse-sloped hull sides, what looks to be HVSS suspension, and a transmission housing reminiscent of the M4 Sherman, yet with Kégresse tracks. The hull is armored, but the driver’s position is poorly protected, with what seem to be supports for windows which had not yet been fitted. Among those who discussed the photos the consensus was clear: whatever it was, it was certainly French.

With the driver’s compartment so exposed and the main armor plates appearing to be no more than 15 mm (0.6 inches) thick, it was unlikely to be a tank. The engine being at the rear and the driver at the very front, there was ample room in the body of the vehicle for it to be an armored personnel carrier, ammunition carrier, or an artillery tractor. Verification that the photos were probably taken in France is given by the second photo, wherein to the right of the mystery vehicle a turretless Renault R.35 can be seen. The greatest indication of its provenance came from the suspension and tracks. Horizontal spring suspension was quite uncommon prior to the invention of HVSS by the United States, and the only other vehicle which paired this suspension type with Kégresse tracks was the Batignolles-Châtillon light tank.

With no information accompanying the photographs and nothing written on the back, the most that could be inferred was that this was an incomplete French prototype, probably from Batignolles-Châtillon. The photos evidence that it was captured by the Germans after the fall of France in 1940, and show it being prepared to be transported elsewhere for examination. This same fate befell many French prototypes, including Batignolles-Châtillon’s other prototype at the time, the DP3.

One of the photos was published in the second edition of the book Tous les blindés de l’armée française des origines à 1940 by François Vauvillier. Vauvillier identified the vehicle as most probably being the Batignolles-Châtillon Automitrailleuse à vapeur (Steam Armored Car), an extremely obscure project which is known from only one line of text.

The project was initiated under requirements issued by the French military on 29 August and 26 September 1934, however the contents of these requirements are not known. Vauvillier suggests it may have been part of the Automitrailleuse de Combat (AMC) cavalry tank project, which was initiated about the same time and which resulted in the SOMUA S35. It is worth noting that although “Automitrailleuse” translates into English as “Armored Car”, the term is more accurately rendered as “armored fighting vehicle”, and was used to refer to certain wheeled, half-tracked, and fully-tracked vehicles.

The only direct mention of the Automitrailleuse à vapeur is from a statement of the progress of various programs dated 1 July 1937. The relevant section reads:

“Étude terminée. Caisse et train de roulement en montage à la Compagnie des locomotives de Nantes. Les deux groupes moteur Sentinel sont satisfaisants et réceptionnés. Formalités de douanes en cours en vue de l’expédition à Nantes.”

English: “Study completed. Body and running gear being assembled at the Compagnie des locomotives de Nantes [Batignolles-Châtillon]. The two Sentinel engine groups are satisfactory and received. Customs formalities in progress for shipment to Nantes.”

The project was classified as “No.2 urgency”, meaning work on it was subject to the time and personnel available to Batignolles-Châtillon.

Sentinel Waggon Works was a British company located in Shrewsbury which manufactured steam locomotives and steam-powered trucks. In 1933, Sentinel launched a new, compact 4-cylinder steam engine and vertical boiler called the S Type, which would power its S4, S6, and S8 range of trucks, the most successful and best-selling steam trucks in history. This is most likely the type of engine which was selected for the Automitrailleuse à vapeur, and as indicated by the above excerpt, the twin S Type engines had been taken delivery of by 1 July 1937 and were en route to the Batignolles-Châtillon factory at Nantes. The S Type engine was a single-acting, 4-cylinder steam engine which weighed 1,007.5 lb (457 kg) and produced 120 brake horsepower. It was fed by a 255 psi boiler which produced 14 lb boiler horsepower, or, in other words, 14 lbs of steam per hour. The boiler consumed 3 lb (6.6 kg) of coal per hour. A Sentinel truck with this engine carried 165 gallons of water and 727.5 lb (330 kg) of coal, enough water for 60 miles (96.5 km) and enough coal for 180 miles (289.7 km) of running at most.

A Sentinel S4. The boiler was mounted in the cab behind the driver, underneath the smokestack, and the 4-cylinder engine was mounted underneath the chassis, the steam manifold being visible here in silver. Source

Scalded to Death by the Steam

The idea of a steam-powered armored vehicle was not new. In fact, some of the very first tank prototypes from World War I were steam-powered. The idea, however, never caught on, for a multitude of reasons. Steam boilers are bulky and difficult to fit within a vehicle where space is at a premium; increasing the internal volume of an armored vehicle will quickly balloon the weight of the armor as a result. They are also fragile, necessitating they be enclosed within the armor if a vehicle is going to be going anywhere near the battlefield. Most of all, steam engines are demanding to operate, constantly needing to be fed fuel, have the water level monitored, and the valving adjusted. They also require intensive maintenance during downtime. Even for a steam truck, it is a good idea to have a second person to tend to the engine; it would be an absolute necessity for a steam-powered tracked vehicle, as the driver would already have his hands full, literally, with steering the machine.

It is difficult to assess the condition of the Automitrailleuse à vapeur from the two photos that exist of it. There would have certainly been enough time to mount the steam engines between when they were acquired in 1937 and when the vehicle was carted off by the Germans toward the end of 1940, however, it is not clear whether the boilers are installed or not. There are no visible smokestacks, and the vehicle is obviously incomplete in other ways, most noticeably the driver’s area. On the other hand, it can be ascertained from the second photo, from the man standing on top of it, that the vehicle does have a roof over its center section. Perhaps the boilers are buried deep within the center of the vehicle, and the steam engines themselves are at the rear. This would be the most efficient layout for the vehicle, though apparently leaving it with an awkward amount of internal space. The area around the driver is clearly very spacious, but not spacious enough for the vehicle to be an effective personnel or ammunition carrier, especially if an engineer would occupy that compartment as well. The second photo seems to show a bulkhead behind the driver’s compartment, but this may be part of the boiler system. It would certainly be desirable to be able to access the boilers from the crew compartment, lest the engineer be forced to ride separated from the driver, which would have a negative psychological effect on both crewmembers.

It may seem that some of the above conclusions are baseless, however they were formulated upon comparison with another steam-powered artillery tractor, one that was also powered by Sentinel boilers, the Škoda SK 13. The SK 13 was a design built in 1945 for the German Wehrmacht by Škoda in Czechoslovakia. It was a last-ditch attempt to provide motive power to the Axis war machine that was desperately short on oil and artillery tractors. The power plant for the SK 13 came from the Škoda Sentinel, an older model of Sentinel steam truck, predating the S Type, which was built under license by Škoda. The boilers used for the SK 13 were larger than the S Type, and the engines less powerful, making only 70 hp each. The SK 13 was slightly larger overall than the Automitrailleuse à vapeur appears to have been, and considering the amount of space taken up by the proportionally larger boilers, likewise everything rearward of the driver’s compartment on the French machine would have to be devoted to the steam engines as well. It seems, therefore, that the only role this vehicle would be suited to is that of an artillery tractor.

The Škoda SK 13. The Automitrailleuse à vapeur and the SK 13 were the last steam-powered armored vehicles to be built. There are a handful of proposals that post-date them, such as a steam power plant for the M47 Patton, but none that would go beyond the drawing board. Source

Ultimately, the Automitrailleuse à vapeur would be largely lost to history, disappearing into Germany like so many of the more famous French prototypes and probably being scrapped before the end of the war. Only a pair of photos fortunate enough to survive give a face to what would otherwise be an incomprehensible footnote in the history of armored vehicles.

Sources:

Two Photographs, from Author’s Collection
Tous les blindés de l’armée française des origines à 1940 – François Vauvillier (Revised Edition)
https://www.sentineldriversclub.com
https://tanks-encyclopedia.com/batignolles-chatillon-light-infantry-tank
https://tanks-encyclopedia.com/skoda-sk-13

WW2 French Prototypes

Renault VM Early Design Version

Post author By Marisa Belhote
Post date November 30, 2022
2 Comments on Renault VM Early Design Version

Renault VM concept as illustrated by Pavel Alexe, funded by our Patreon campaign.

France (1931)
Light Armored Reconnaissance Vehicle – Design Only

During the interwar years, the French Army’s cavalry service was a force actively seeking new types of vehicle to introduce to its forces, generally more so than the better-funded infantry. There were active doctrinal developments within the Cavalry which led to new roles being created, for which various manufacturers would offer designs. In the early 1930s, the concept of a very light vehicle tasked with reconnaissance duties and armed with a machine gun was gaining popularity within the Cavalry. The Citroën P28 was the first vehicle adopted, in 1931. Renault, the largest vehicle manufacturer in France, did not want to allow its competitor Citroën to gain the lead and be able to sell vehicles to the French Army uncontested. As Citroën had done, it began the design process based on a logistical armored vehicle it had recently designed. A turreted light tank/tankette model designed in this manner was already in existence by late 1931.

Reconnaissance Vehicles and Citroën’s Successes

The French Cavalry ended the First World War with a varied fleet of armored cars of various weights, sizes and armaments. In the interwar years, the need for new, more modern vehicles was apparent, including vehicles which could fulfil a reconnaissance role.

In July 1930, the French Army approved an ambitious program which was to lead to the creation of vehicles to fulfill a large variety of roles. This was the general motorisation program. It called for two types of vehicles which would fulfil a reconnaissance role: a voiture de reconnaissance tout terrain blindée (Eng: all-terrain reconnaissance armored car) and a Automitrailleuse légère tout terrain (Eng: all-terrain light armored car). “Automitrailleuse” is a term that, although often translated as armored car, when used in the context of interwar French Cavalry, is used to designate all armored combat vehicles, regardless of means of motion. In other words, a program that, in English, would be translated as an armored car program, could in fact refer to a half-track or fully tracked

The first requirement would eventually evolve into the Type L armored car specification, for which Renault would produce the ill-fated Renault URL armored car.

The armed Renault UE prototype. This was an experimental prototype created shortly after the early VM for demonstration purposes, with the only change from the original UE being a raised compartment for the co-driver, who was tasked with operating the machine gun. Source: Renault documentation via Les Automitrailleuses de Reconnaissance, Tome 1: L’AMR 33 Renault, François Vauvillier

In comparison, the second set of requirements would quickly fall under the influence of a specification for a vehicle which would be ordered in much higher numbers – the Type N. The Type N was envisioned as a lightweight all-terrain, lightly armored infantry tractor and cargo vehicle. Three companies produced vehicles for this program: Latil offered a licence-built Carden-Loyd Mk.VI; Citroën offered the Citroën P28 chenillette, a half-tracked vehicle; and Renault offered a tankette, inspired by the general design features of the influential Carden-Loyd but by all means its own design. This was the Renault UE, a light (2.64 tonnes) and tiny (2.8 m long, 1.74 m wide, and 1.25 m high) tankette with a crew of two and protected by thin, bulletproof armor. It had a leaf spring suspension with three bogies containing two road wheels each, using a front sprocket and rear idler and supported by two return rollers.

Creating a Reconnaissance Vehicle Using the Renault UE as the Basis

The specifications of the Type N, which called for a lightweight, fairly mobile, bulletproof vehicle, co-incidentally proved to create designs which would provide a good basis for the kind of light reconnaissance vehicles the French Cavalry was seeking. Both Citroën and Renault would offer vehicles to fulfill such a role based on their logistical tankettes. Citroën offered a modified version of its P28, which was ordered in October 1931.

The Renault design was created around the same timeframe as the Citroën, in autumn 1931. The design would retain the same very short length of 2.8 m as the UE, and perhaps the same or at least a similar width of 1.74 m. However, there were major structural changes to the vehicle. Renault gave this modified design the internal code “Renault VM”.

Instead of retaining the front crew compartment, centrally-placed engine, and rear-mounted stowage area of the original UE, the VM’s crew compartment would instead be placed towards the left and rear of the vehicle, with an engine to the front and right.

A side schematic view of the early Renault VM, showing the similar drivetrain in comparison to the UE, as well as the turret and crew positions. Source: Renault documentation via Les Automitrailleuses de Reconnaissance, Tome 1: L’AMR 33 Renault, François Vauvillier

The largest difference in the vehicle design was the presence of a turreted armament. The early VM design featured a turret which was mounted on the left of the vehicle, behind the driver’s position, which was positioned in the same way as on an UE. The turret featured on the schematics of the vehicle was a fairly simplistic design. It would be armed with the new machine gun available for fortifications and armored vehicle designs, the 7.5 mm MAC 31. The MAC 31 Type E had a weight of 11.18 kg empty and 18.48 kg with a fully loaded 150-round drum magazine. The machine gun was gas-fed, and had a maximum cyclic rate of fire of 750 rounds per minute. It had a muzzle velocity of 775 m/s. The ammunition stowage present on the early Renault VM design is unknown. The turret would have housed a single crewmember, the gunner/commander. It appears that a small cupola would have been placed towards the rear of the turret, and would likely have had some sort of vision device, such as a panoramic periscope. From the design, the turret appears to have been very small overall, to the point it would have been quite cramped. It also appears that no reloads for the machine gun would be present in the turret, with all the magazines (the MAC 31 using 150-rounds drum magazines) having to be stowed inside the hull instead.

The other major structural change of the early VM design in comparison to the UE was the engine, with the early VM being designed to have a more powerful engine. Its potential horsepower output is unknown, as Renault used an alternative means of power measurement for it, CV. It would have been a 15 CV engine. In comparison, the original UE’s Renault 75 was a 10 CV engine producing 30 hp, while the AMR 33’s 24 CV engine would produce 84 hp. Unlike the centrally-mounted position on the UE, the engine was shifted to the right on the early VM design. This would have been a fairly uncommon feature at the time. As lateral space was quite limited, the radiator and ventilator would have had to be shifted at 90° and be installed to the rear of the engine, in a fairly distinct manner which would have also been quite rare at the time. The radiator, in particular, would have been installed as far to the back as the turret would have been, and the gunner would have effectively been sandwiched between the radiator on his right and the hull’s wall to the left.

A top view of the early VM design’s structural arrangement, showing the position of the crew as well as the engine block, which extended over the whole short 2.7 m length of the vehicle. Source: Renault documentation via Les Automitrailleuses de Reconnaissance, Tome 1: L’AMR 33 Renault, François Vauvillier

The suspension of the vehicle would have used the same components as the Renault UE, with three leaf springs bogies on which two small road wheels were mounted, a front sprocket and a rear idler. However, unlike on the UE, the sprocket and idler would have been placed higher. Though the return rollers are not seen on the schematics, they would very likely have been present.
Armor protection at this point in time would also very likely have been the same as the UE, with 9 mm on vertical surfaces and 6 mm on all other plates.

Rejection

Renault’s early VM design was submitted to the technical services of the French Cavalry at some point in autumn 1931. The vehicle was formally rejected by the French Cavalry on November 12th 1931.
A first review of the design by the French Cavalry was fairly negative. Several design choices of the vehicle were deemed subpar and proved unpopular, as some of the design features were quite unconventional for the time. Among which was the rear-turreted configuration, which the French Army would continue to object to on future evolutions of Renault’s light armored vehicle proposals. Another source of discontent was the engine’s offset mounting to the right. Furthemore, the engine was not thought to be powerful enough to allow for the vehicle to reach a high enough speed. This was further worsened by the use of a suspension almost identical to the UE, with six small road wheels mounted on leaf springs, which would generally favor cross-country mobility but make reaching higher maximum speeds harder. There were also issues with the proposed placement of the radiator all the way to the right, with the position of the commander, cramped between the radiator and the left wall of the vehicle.

During the same period, the French Cavalry had been somewhat pleased with the design of Citroën’s offer, the P28, and had ordered 50 vehicles of a modified version of the half-track tractor, now fulfilling a light reconnaissance vehicle role. As such, there was no immediate need for a swift replacement at this point in time, though the P28 was not viewed as a viable long-term solution but only as a stopgap.

Conclusion – A Failure which would Lead to Many Successes

The rejection of the early Renault VM in November 1931 would not be the end of Renault’s light reconnaissance vehicle designs, far from it. The P28 was considered to only be viable as a stopgap solution, and there was still a need for a more capable vehicle to offer a more durable reconnaissance platform. Formal specifications for such a vehicle would be formulated by the French Army on January 16th 1932.

One of the five Renault VM prototypes, n°79 756, is seen during the large French Army maneuvers of summer 1932. Source: Les Automitrailleuses de Reconnaissance, Tome 1: L’AMR 33 Renault, François Vauvillier

Renault would provide a modified version of its existing VM design, which would undergo many changes, most notably, a lengthened hull allowing for less tight and cramped spacing, a more powerful engine, and a new suspension and turret designs. Five prototypes of this design would be ordered in April 1932 and, in a true industrial feat at the time, completed in time to participate in large French Army maneuvers in the summer of 1932. These would eventually lead to the AMR 33, of which 118 new production vehicles would be manufactured in addition to the five prototypes. After this the even more produced AMR 35, a further evolution of the VM design, came. These were two success stories for Renault’s 1930s armored fighting vehicles design, despite the failure of the original VM design.

Renault VM concept as illustrated by Pavel Alexe, funded by our Patreon campaign.

Renault VM Early Design Version Specifications
Dimensions (L x w)	2.7 x likely 1.78 m
Suspension	Leaf springs
Road Wheels	6
Engine	Renault 15CV engine
Crew	2 (driver, commander/gunner)
Armament	7.5 mm MAC31 machine gun
Armor	6-9 mm

Sources

Les automitrailleuses de Reconnaissance, Tome 1: l’AMR 33 Renault, François Vauvillier, Histoire & Collection editions
Tous les blindés de l’Armée Française 1914-1940, François Vauvillier, Histoire & Collection editions
Char-français: http://www.chars-francais.net/2015/index.php/engins-blindes/automitrailleuses?task=view&id=70

Has Own Video WW2 French Prototypes

Jacquet Assault Train

5-way vies of the Jacquet Assault Train, showing off the articulated design and the odd turrets.

France (1944)
Articulated Vehicle – Design Only

Victor-Barthelemy Jacquet is not a French designer with golden name recognition, like Louis Renault or Colonel Jean Estienne, the fathers of the Renault FT and French tanks respectively. Indeed, virtually nothing is known of him outside of a few patent applications submitted between 1922 and 1944. It is this final patent, submitted at a time when France was being liberated from the Germans by the Allies, which was perhaps one of the oddest tank designs of the war – a train tank or, in modern parlance, a cybernetically connected articulated armored fighting vehicle.

The Man

Little can be found about Victor-Barthelmy Jacquet. What is known is that he submitted his first patent in France in 1922, followed by 7 more filings in Great Britain and France over the next 22 years. His penultimate patent was for this ‘train d’assaut’. His patent filings were technical in nature and showed a degree of engineering mechanical competency, so it is fair to assume that Jacquet at least had a degree of engineering knowledge. When it comes to the ‘train d’assaut’, there are not many clues from which to work for providing additional background on Jacquet, not even his address at the time. However, this was disclosed in the 1922 application in Great Britain for a patent on his reversible motor pump. At that time, he was living at 20 Boulevard de Villiers, Levallois-Perret, right in the heart of Paris. Today, this is a rather anonymous and mundane white apartment block with commercial premises underneath. Where Jacquet may have resided 22 years later is unknown, nor is the reason for the hiatus from 1922 to his next patent in 1943.

A French ancestry site (geneanet.co.fr), which cannot be verified, shows a trace of a Victor-Barthelmy Jacquet born in Montbrison, west of the city of Lyon on 6th December 1883 and dying in Paris on 7th May 1947, aged 67. If that entry is correct, then Jacquet was born as one of 11 children and had served in WW1 (1914-1919). He would have been 31 years old at the outbreak of WW1, and 39 when he submitted that first patent. At the outbreak of WW2, in 1939, he would have been too old for military service at 56 years of age and in 1944, when he submitted this assault train idea, 61.

He is certainly not to be confused with Victor Eugene Alexandre Jacquet from Montbrisson, born two years later (1885) and who died in 1946. That Jacquet was a poet and may have been a relative or just someone sharing a similar name, it is unclear which. If geneanet.co.fr has the correct Victor-Barthelmey Jacquet, then this Victor Eugene Jacquet is not a sibling.

Design

The design of Jacquet’s assault train was simple and complex, all in one package. Simple in theory and complicated in design. The fact that this was as far as it went belied the fact that to put such a vehicle into use would border on the fiendishly complex. Consisting of 3 distinct and different sections, known as ‘cabins’, the design connected all three of them together with a hydraulic coupling allowing for independent movement. In total, this vehicle would amount to some 6 to 7 meters long, with around 0.5 m of ground clearance. Using hydraulic pressure, the coupling could also be locked to assist in obstacle crossing. Each section had its own independent track system and turret.

Jacquet’s assault train, as seen in his 1944 patent application, climbing a short escarpment. The image has been digitally cleaned for clarity.
Source: French patent FR992901

The unusual shape of all three cabins left the leading section angled down and forwards, rather akin to the shape of the bonnet on a car. All three cabins were vertically sided with a rounded upper hull. The turret on cabin 1, mounted in the center of this part of the vehicle, could, therefore cover a very shallow angle to the front – ideal for spraying fire into the steep angle of a trench or for when this leading cabin cleared a slope. It also allowed for the turret on the larger and longer cabin in the middle to overlook the entirety of cabin 1, including its turret, meaning it could also fire to the front as well as to the sides. The third cabin, in the rear, was, like cabin 1, small and angled with a turret operating canted. The angle of the hull roof slope was not as sharp as that on cabin 1. Cabin 3 was also slightly larger than cabin 1 as well. All three turrets followed the same shape.

Harder to tell from the side image was that the leading cabin was also narrower than the main cabin in the middle. This allowed for weapons mounted in the leading edges of this central cabin to fire past the forward cabin.

Front view of Jacquet’s Assault Train. No armament shown in the foremost turret. Modified and adapted from French patent FR992901.

Suspension

All three cabins were tracked, using a relatively straightforward system consisting of a large drive sprocket and a toothed idler at opposite ends of the track. Between these large wheels were what appears to be four double sets of wheels connected together in pairs on either side of a heavy inverted elliptical spring, allowing vertical movement of the bogies. Each bogie was effectively split in two, with one wheel-pair in each piece and the two pieces connected together via a pin, allowing the wheel pairs to move slightly independently of each other. The inner of those two-wheel pairs, consisting of the inner half of each bogie, was connected by another set of leaf springs. To add to the suspension provided by those two sets of elliptical springs, a third set, consisting of half-elliptical springs, was fixed firmly at the top to the hull side and flexibly at the bottom to the foremost wheel on the foremost bogie. The rearmost end of the rearmost bogie was affixed to the hull via a vertical arm and, thus, the entire system could move as one, individually or as bogies. Whilst that is simple enough, albeit far from modern for a tank in 1944 which could be on a more modern system, like volute springs or torsion bars, it was still viable.

The suspension system for each of the cabins of the Assault Train. Note that the tracks are facing left to right. Modified and adapted from French patent FR992901.

Automotive

The center cabin carried the engine and primary gearbox for the vehicle, ensuring that the heaviest mechanical components were mounted close to the center of gravity. From there was a rather complicated system of secondary drive elements to carry power from this primary gearbox to the drive sprockets at the back of the center cabin and, via a long drive shaft, to a powered differential at the rear of the rearmost cabin. Although not shown in the plan view drawing in the patient, the output from the gearbox also went forwards down the center line of the vehicle to the front cabin, to presumably another powered differential at the front of the tracks.

Plan view of the main cabin (right) and the smaller fore or aft cabin (left). The image has been digitally cleaned for clarity. Source: French patent FR992901

Seating position for the crew in the center cabin of the vehicle is shown along with the steering levers. The image has been digitally cleaned for clarity. Source: French patent FR992901

Steering for the vehicle was delivered by means of levers and pedals for braking the tracks, accelerating the engine, and also controlling the hydraulics for moving the cabins in what must have been the most complicated driving job imaginable. This would be made worse by the fact that the driver was positioned high up centrally in the middle section of the vehicle, using the turret for visibility. This meant his view forwards on the ground would be totally obscured by the leading cabin.

Armament and Protection

Protection for all three cabins of the vehicle was provided by a body that was well rounded and made from cast type of steel of either manganese steel or another suitable alloy. Inside this cast steel shell would be the necessary supports, pre-made for the attachment of all of the mechanical components, such as the engine and transmission.

Weapons for the assault train are unnamed but, in his patent application, Jacquet describes how the cast steel body would come with supports cast to hold various components and weapons and any “.. liquids, gases, compressed air, etc., necessary for …. The defense of the assault train”. Whilst some of those elements may also form parts of the propulsion or fuel system, there is clearly also the potential envisaged for at least the use of hazardous liquids and gases for defensive purposes, effectively meaning either something corrosive, poisonous, and/or flammable.

To add to the burden and the otherwise difficult working position of the driver, he would also find himself sat alongside the primary armament of the cabin, which was fitted in the turret.

The rear cabin was designed to house a single 75 mm gun which, very oddly, was pointed directly backward out of the hull of the cabin rather than in the turret. Aiming the gun would therefore be a function of aiming the entire rear of the vehicle at the target. The patent further elaborated on armament by suggesting that other anti-tank guns, machine guns, or a “compressed air mine tube against anti-tank barriers” could be added, without providing any conception as to what that weapon might look like.

As a basic outline of the armament spread across the three cabins and turrets, there would be 4 machine guns and 2 cannons and the drawing clearly shows at least two of those machine guns protruding from the forward face of the central cabin. It is logical to assume that some armament would be mounted in each turret. Given that the leading cabin had the turret so sharply canted, there seems little point in a large cannon in that turret, being so limited in use. A reasonable estimate, therefore, of armament might be for just a single machine gun in that leading cabin’s turret, two in the sides of cabin 2, and a single machine gun in the turret of cabin 3, making 4 in total. With a large caliber gun presumably for firing high explosive shells, like the French 75 mm, in the rear of cabin 3, this would only leave the turret in cabin 2 to find a suitable armament for. Given the small size of the turret and the fact that the driver is also sharing it, whatever cannon or other armament mounted therein would have to be fairly small and would serve to complicate both driving and firing.

Crew

No specific crew is listed or detailed by Jacquet but, based on his drawings and description, an estimate can be made. Only one man was needed to drive the vehicle (cabin 2) along presumably with a commander – again, best positioned in the turret of cabin 2, and therefore probably having to operate the gun as well. At least one other crewman would be needed in cabin 2 to operate the hull machine guns on one side and two men if both were to be operated at the same time, for a total of 3-4 men (commander, driver, machine gunner x 2) in cabin 2.

Cabin 1, with no driving to do, would need at least one man to operate the gun and possibly a second to assist with loading or observation (machine gunner, assistant). The same is true in the rearmost cabin (cabin 3), with the added complexity of the large field gun which would need at least two men to operate so that it could be loaded, aimed, and fired with any degree of alacrity. That would mean not less than 3 and more likely 4 men (turret machine gunner, field gunner, two loaders) there. This means that across the three cabins, at least 8 and maybe as many as 10 men would be needed to operate the entire vehicle.

Articulation

This was certainly not the first articulated fighting vehicle concert. The first of the modern era was from British Colonel R. E. B. Crompton in 1915, with two tractors connected back to back in an effort to make a longer tracked vehicle for crossing trenches. It is this obstacle crossing ability which was, and still is, appealing to designers of articulated vehicles, like the plan for a set of additional tracks on the front of the St. Chamond in WW1, Delahaye’s 1918 design for a multi-tracked articulating vehicle, or the design for connecting a whole series of tanks together from M. Boireaux in 1936. They all used this characteristic to dramatically move one set of tracks from the other to increase the mobility of the vehicle over rough terrain or obstacles.

It is not known if Jacquet knew of some or any of these preceding ideas or not or if this was just a case of convergent thinking. Either way, the outcome was the same – using a system of articulation of one or more sections of track, whether independent on a chassis or not, to increase obstacle crossing.

The means by which Jacquet’s vehicle was to cross an obstacle was, much like the other ideas, to use one or more sets of tracks on a body or bodies. For Jacquet, in his three-cabin vehicle, it was the smaller leading cabin that led the way in crossing obstacles and this was achieved with a hydraulically controlled bearing between the cabins, which allowed for both vertical and horizontal movement. Cabin 2, the larger of the three cabins and located in the middle, provided the bulk of the system, with the third cabin at the back acting almost as a tail and balance for the whole lot. Between the cabins were effectively spheres, with a third of the front and rear removed and with the remaining part able to fit into the adjoining piece, giving the appearance of a concertina effect when in operation. For the connection between cabins 1 and 2, this was formed from three such ‘cut spheres’ forming the connection, but only two for the connection between cabins 2 and 3.

The three cabins of Jacquet’s Assault Train seen from above, showing the horizontal movement available to it. Note that the image has been digitally cleaned for clarity.
Source: French patent FR992901

When the system came to a vertical obstacle, such as a wall or even a cliff up to the height of the whole vehicle, it would begin to scale it by elevating the leading cabin hydraulically. Lifting this off the ground and then moving cabins 2 and 3 forwards would push cabin 1 up the cliff. As cabin 1 got to the top, the middle cabin would come off the ground but be hauled forwards by the trailing cabin, helping to provide forward thrust, as well as what traction cabin 1 could purchase at the top of the escarpment. As cabin 1 cleared the top, this tractive effort increased and brought cabin 2 to the top just as cabin 3 started to leave the ground and provided less and less traction.

Diagrammatic cross-section of the leading section of the vehicle, showing the engine and primary gearbox, along with the circles indicating the articulation. The rounded body work is also apparent. Note that the image has been digitally cleaned for clarity.
Source: French patent FR992901

Thus, all the pieces of the vehicle would act in sympathy with each other. As one piece lost traction, the others gained it, balancing out the forces needed. Even in the case of a vertical face, the system could work on paper.

The means by which the tank could climb a sheer cliff face as tall as itself.
Images adapted and modified from French Patent FR907544.

In the case of a wide gap, such as a particularly unpleasant anti-tank ditch, river, or canal, the system still worked. However, instead of elevating the leading cabin of the vehicle, the coupling could be locked and cabin 1 pushed ahead into the gap. As long as the center of gravity of the vehicle was not exceeded in pushing this leading cabin out in the void, the whole train would remain level on the other side of the gap. By the time cabin 1 reached the other side, cabin 2 would be exiting the bank, and cabin 1 would be pulling it across and so on for cabin 2 and cabin 3, with the coupling locked. Assuming that the gap allowed for a small dip onto the facing bank, like crossing a river, then the gap crossable could be even larger than that of the distance to the center of gravity. This relatively small vehicle of three parts possessed a remarkable level of agility which would set it apart from a more conventional design.

Original page from Jacquet’s patent.

Conclusion

Jacquet’s Assault Train swerved headlong into oblivion as a design. Once the basic elements were drawn as they were, Jacquet had committed the vehicle to an impossibly complex drive and hydraulic system to navigate even relatively modest obstacles. Hard to drive, complex to maintain, impossible to command to any effect, the vehicle rightly was as poorly thought-out as it was likely for production or adoption.

Many of the same problems with articulated vehicles which existed prior to this design and which continued to exist thereafter, such as control over the separate sections of the vehicle, how to command and operate it, how to effectively lock and release a hydraulically actuated flexible coupling, were unresolved. Jacquet’s solutions were just like his suspension design – simple in thought, complex in practicality and worse than every other available alternative. There was absolutely no likelihood of this design reaching any stage of trials or production with an armed force as it was laid out. If the technical issues were not bad enough, then the ludicrous number of crew required to operate it should be sufficient to kill it off. A vehicle needing 8 to 10 or more crew was simply never going to be a viable concept when contemporary vehicles fielded by Britain, France, the USA, and the Soviet Union, were 4 and 5 man crews for substantially more tank for the effort.

A slight ray of light for the vehicle was the basic concept of articulation. Whilst it was certainly not new at the time, it was at least clear on how an articulated vehicle of more than 2 sections could have an advantage over a 2 piece design. Namely, a three-piece vehicle could climb even higher obstacles or cross even greater gaps using that third cabin at the back as a tail. Nonetheless, the patent was accepted in July 1951 and quickly filed and forgotten.

5-way vies of the Jacquet Assault Train, showing off the articulated design and the odd turrets.

Front-right view of the Jacquet Assault Train cresting a rise. The advantages of the articulated design are evident.

The same from the rear. All renders done by Giganaut, funded by our Patreon campaign.

Specifications – Jacquet’s Assault Train

Crew: est. 8 – 10 men (driver, commander, machine gunners x 4, artillery gunner, loaders x 2)
Dimensions: 6 – 7 metres long. 0.5 m ground clearance.
Armor: cast steel or manganese or other alloy cast armour
Armament: Optional single 75 mm cannon, anti-tank guns, multiple machine guns, compressed air explosive launcher

References

French Patent FR545918 Moteur rotatif reversible, filed 14th January 1922, granted 4th August 1922, published 4th October 1922
British Patent GB191718 Reversible Rotary Motor or Pump, filed 29th December 1922 – application not accepted.
French Patent FR887564 Dispositif Differential, filed 6th November 1942, granted 16th August 1943, published 17th November 1943
French Patent FR897490 Disposif de changement de vitesse, filed 24th August 1943, granted 30th May 1944, published 22nd March 1945
French Patent FR90371 Machine rotative, filed 6th June 1944, granted 10th September 1945, published 8th April 1946
French Patent FR906066 Motor-thermique, filed 25th July 1944, granted 7th May 1945, published 21st December 1945
French Patent FR992901 Train d’assaut, filed 25th September 1944, granted 18th July 1951, published 24th October 1951
French Patent FR907544 Disposif de transport a patins et roues commandees, field 31st October 1944, granted 2nd July 1945, published 14th March 1946
Forehistoire.free.fr http://forezhistoire.free.fr/56-ph-victor-jacquet.html

WW2 French Prototypes

Automitrailleuse Renault UE

Post author By Marisa Belhote
Post date January 22, 2022
No Comments on Automitrailleuse Renault UE

The Automitrailleuse Renault UE. Illustrated by Pavel "Carpaticus" Alexe, based on work by Tank Encyclopedia's own David Bocquelet and funded by our Patreon campaign

France (1931-1932)
Tankette / Reconnaissance Vehicle – 1 Converted

During the interwar years, the French Army’s Cavalry service was a force actively seeking new types of vehicle to introduce to its forces, generally more than the better-funded infantry. There were active doctrinal developments within the Cavalry which led to new roles being created, for which various manufacturers would offer different designs.

In the early 1930s, the concept of a very light vehicle tasked with reconnaissance duties and armed with a machine gun was gaining popularity within the Cavalry. A first vehicle would be adopted in 1931 in the form of the Citroën P28.

Renault, the largest vehicle manufacturer in France, did not want to allow its competitor Citroën to gain the lead and be able to sell vehicles unchallenged to the French Army. Before more complex and specific vehicles would be developed and offered, Renault’s first light reconnaissance vehicle was a Renault UE modified to feature a small machine gun casemate. This basic vehicle served as a step in the developmental process which would lead to the Renault VM, a vehicle which would be adopted by the French Army as the AMR 33.

The armed Renault UE prototype. Source: Renault documentation via Les Automitrailleuses de Reconnaissance, Tome 1: L’AMR 33 Renault, François Vauvillier, colorized by Smargd123

Reconnaissance Vehicles and Citroën’s Successes

The French Cavalry ended the First World War with a varied fleet of armored cars of various weights, sizes, and armaments. In the interwar years, the need for new, more modern vehicles was apparent, including vehicles which could fulfil a reconnaissance role.

In July 1930, the French Army approved an ambitious program which was to lead to the creation of vehicles to fulfil a large variety of roles. This was the general motorisation program. It called for two types of vehicles which would fulfil a reconnaissance role: a voiture de reconnaissance tout terrain blindée (Eng: all-terrain reconnaissance armored car) and a automitrailleuse légère tout terrain (Eng: all-terrain light armored car). “Automitrailleuse” is a term that, although often translated as armored car, when used in the context of interwar French Cavalry, is used to designate all armored combat vehicles, regardless of means of motion. In other words, a program that, in English, would be translated as an armored car program, could in fact refer to a half-track or fully tracked vehicle.

The first requirement would eventually evolve into the Type L armored car specification, for which Renault would produce the ill-fated Renault URL armored car.

Of the three options, the Renault UE was the French Army’s favourite option and would be adopted into service. The vehicle was a light (2.64 tonnes) and tiny (2.8 m long, 1.74 m wide, 1.25 m high) tankette, with a crew of two and protected by thin, bulletproof armor. It could carry large quantities of rifle, machine gun, mortar, or anti-tank gun ammunition in a storage box mounted to the rear of the vehicle. Furthermore, the vehicle was also used to tow either a tracked trailer (designated Renault UK) containing more supplies, or in the future, the 25 mm SA 34 anti-tank gun. It was even possible to tow both, with the gun following the trailer.

Schematics of the Renault UE, showing the general design of the vehicle and the placement of its powertrain. Source: Renault documentation via Les Automitrailleuses de Reconnaissance, Tome 1: L’AMR 33 Renault, François Vauvillier

While the Renault vehicle was preferred in the infantry cargo and prime mover role, the Citroën P28 gathered significant interest from the Cavalry. It was considered as a good candidate for conversion into a light armored car, and, in October 1931, likely even before Citroën could provide a prototype of a vehicle modified for such a role, an order for 50 was notified. These would be the vastly modified Citroën P28 armored cars.

A Renault UE with a Machine Gun

Though the Citroën P28 gathered the most interest from the Cavalry early on, it did not completely forget about Renault, which was itself eager to provide a vehicle and offer a competitor to Citroën’s sudden success.

On November 21st 1931, the STC (Service Technique de la Cavalerie – Cavalry Technical Service) required Renault to provide two Renault UEs for a presentation to a Dragons Portés (Eng: mechanized dragoons) unit. Crucially, the STC requested one of the two vehicles to be armed. This request was made for a presentation which was to take place only nine days later, and this timeframe was considered too short to reasonably modify a UE to feature an armament.

However, while Renault could not produce a conversion for this specific presentation, the request from the STC made it very clear to Renault that there would be official interest in an armed version of the UE from the French Cavalry. Work quickly began on realizing such a conversion. By late 1931, Renault UE prototypes (six had been manufactured) were still undergoing trials for the French military, and the first production vehicles would only be delivered in 1932. As such, creating such a vehicle on such a short notice would be accomplished by modifying an existing prototype.

It ought to be noted that Renault was already working on a more complex and dedicated design by that time. A first proposal for a turreted, Renault UE-based vehicle had already been passed onto the French Cavalry and rejected on November 12th 1931. However, while work on more advanced vehicles was still at the design phase, a simple conversion on an existing Renault UE would allow to have a vehicle “in steel”, easier to experiment on, much quicker.

A front view of the modified Renault UE. The simplistic nature of the conversion can be seen. Source: char-français

Schematic views of the conversion. A gunner would be sat on the floor, with their eyes on the same level as the machine gun’s sight. Source: Renault documentation via Les Automitrailleuses de Reconnaissance, Tome 1: L’AMR 33 Renault, François Vauvillier

The modified vehicle would be the prototype registered as “n°77 982”. The modifications made to the vehicle were very simple. The roof of the co-driver’s compartment was raised by a small extent, using the same riveted construction as the rest of the vehicle. The dome-shaped cupola was retained. This raised compartment allowed for enough internal space for a machine gun to be added. This was the new machine gun available for fortifications and armored vehicle designs, the 7.5 mm MAC 31. The MAC 31 Type E had a weight of 11.18 kg empty and 18.48 kg with a fully loaded 150-round drum magazine. The machine gun was gas-fed, and had a maximum cyclic rate of fire of 750 rounds per minute. It had a muzzle velocity of 775 m/s. The ammunition stowage present on this vehicle would have been unknown, but likely quite limited.

This vehicle would be one of the first to use the new machine gun. It would, in the following decade, be present on almost every single French armored fighting vehicle. The exact weight added by the conversion is unknown. It would likely have been quite limited, and the weight of the modified Renault UE likely stayed under the 3 tonnes mark. Following the modification, the co-driver had to operate as the commander of the vehicle and gunner, with an optical sight present on the top-right of the gun in order to aim.

A Tiny Step Forward

The modified prototype was presented to the French Cavalry at an unspecified date in early 1932.

The 1st BDP (Bataillon de Dragons Portés) carried out operational testing. These trials generally underlined shortcomings of the vehicle when it came to fulfilling the light armored car role which was desired from the conversion.

Besides the machine gun, the modified Renault UE had been kept almost completely untouched. The vehicle retained the Renault 75 four-cylinders gasoline engine, mounted in the center of the vehicle, and producing a mere 30 hp. The leaf spring suspension with three bogies containing two road wheels each, using a front sprocket and rear idler and supported by two return rollers, remained the same. This suspension type was optimized for cross-country mobility rather than top speed. A standard UE would only reach a maximum speed of 30 km/h on road, and it is likely the machine gun armed version would achieve the same. The operational range of 100 km, though not awful, was also not perfect for a reconnaissance vehicle which could be placed into situations where it had to operate on its own for fairly extended periods of time.

The vehicle is seen during its trials, towing the Renault UK trailer. Source: loutan.net

The vehicle also retained all the elements which would have been found on the regular UE dedicated to an infantry logistical role. As such, it featured the rear stowage area, and even the towing hook. The armed prototype was seen towing a UK trailer in trials. This does mean it would retain the non-negligible carrying capacities of the UE. The storage area at the rear of the vehicle had a standard load of 8,100 7.5 mm ammunition in the form of FM 24/29 machine rifle magazines, 2,688 8 mm Lebel rifle cartridges, 150 hand grenades and 114 rifle grenades. The ammunition load transported by the vehicle could obviously be adjusted regarding which need it was to fulfil, with a full load of 7.5 mm cartridge being of a maximum of 18,000 in the UE’s own storage area alone. The standard load on the UK trailer was of 162 81 mm mortar rounds and 8,500 8 mm Lebel rifle cartridges, or alternatively 15,000 8 mm Lebel rifle cartridges. Generally, an UE and its trailer were considered to be enough to supply a mortar group or machine gun section.

While these logistical capacities could perhaps provide somewhat of an appreciated versatility, they did nothing to compensate for the fact the vehicle was woefully unadapted for combat. The casemate-mounted machine gun configuration was far inferior to the turreted Citroën P28, and unlike the French Infantry, the Cavalry tended not to entertain the concept of non-turreted vehicles and instead preferred only turreted ones. While the armor of a light reconnaissance vehicle would by definition be light, the Renault UE’s protection, with the vertical plates being 9 mm thick and all others being 6 mm thick, was likewise still quite light for a vehicle of the type.

Conclusion – The Unknown Fate of an Experiment

It should serve as no surprise that the armed Renault UE was not adopted by the French Army (though other forms of armed UEs would appear in the following years due to the eventual large-scale production of the vehicle, with some even armed with 25 mm anti-tank guns in the campaign of France, or surprisingly, similar machine gun-armed conversions being produced and sold to China, or created in the field in French Indochina). The vehicle was not adapted to provide a reasonable, mobile reconnaissance vehicle with a turreted armament. Renault was keenly aware of this, and their offer of an armed UE should likely only be taken as a way to prepare work on a more advanced vehicle dedicated for the role, as well a way not to leave the field of a light armored car entirely in the hands of Citroën while Renault was working on its own future vehicle.

Taking the UE as a base, Renault would eventually produce a much more mature, turreted design, with a different, frontally-mounted engine. This would be the Renault VM, which would be adopted by the French Army as the AMR 33. Including prototypes, 123 were produced, marking the start of an era of the 1930s where Renault would see several of its designs adopted by the French Cavalry, including later down the line the AMR 35 in a reconnaissance role, but also the AMC 34 and AMC 35 as cavalry combat vehicles.

As for the modified Renault UE, its fate is unknown. The vehicle could have been scrapped, or even have its modifications reversed to continue serving in an experimental role. Considering it was always a prototype though, being scrapped at some point in the following years appears to be the most probable hypothesis.

The Automitrailleuse Renault UE. Illustrated by Pavel “Carpaticus” Alexe, based on work by Tank Encyclopedia’s own David Bocquelet and funded by our Patreon campaign

Automitrailleuse Renault UE Specifications
Dimensions (L x w)	2.8 x 1.78 m
Weight	Likely between 2.64 and 3 tonnes
Suspension	Leaf springs
Road wheels	6
Suspension	Torsion Bars
Engine	Renault 75 4-cylinders gasoline engine producing 30 hp
Maximum Speed	Around 30 km/h
Crew	2 (driver, commander/gunner)
Armament	7.5 mm MAC31 machine gun
Armor	6-9 mm

Sources

WW2 French Prototypes

Citroën P28 Chenillette

France (1931)
Infantry Tractor – 3 Prototypes Built

The early 1930s were marked by the worldwide popularity of the tankette concept, which produced a variety of vehicles used in sometimes quite radically different manners across most major industrial powers of the world. The Citroën P28 original prototype was one of the more original derivatives of this design. Designed to serve as an infantry tractor, it used a half-track configuration with Kégresse suspension, which makes it a quite interesting and original design. While not adopted as an infantry tractor, with the more traditional fully-tracked Renault UE being picked, it became an interesting half-track cavalry armored car.

In the wake of the Carden-Loyd

In 1928, production of the British Carden-Loyd Mark VI tankette began. The result of several years of experimentation on one and two-man turretless armored vehicles, this British tankette was a 1.5 ton heavy vehicle with a two-men crew. A novelty on the international market, which was relatively stagnant and dominated by the WW1-era French Renault FT, the Carden-Loyd seemed to offer new possibilities as a lighter and cheaper armored vehicle.

The potential was not lost on France and, in June and July 1930, two Carden-Loyds were tested at the Centre des Essais de Véhicules (Vehicles Trials Center) of Vincennes. Those trials had been conducted at the initiative of engineer Edgar Brandt. Brandt was a prolific artillery designer, responsible notably for the Brandt 27/31 81 mm mortar, an evolution of the British Stokes that would, in turn, be adopted, modified, and/or copied by virtually every major and many minor military powers of the 1930s. It is reported two different Carden-Loyds were tested, one of a “light” and one of a “heavy” model. The light one could be outfitted with a machine-gun and used as a small combat vehicle, while the heavier one was tried as an armored tractor with a tracked trailer, with the purpose of carrying the Stokes-Brandt mortar and ammunition.

The Type N program

The trials of the two Carden-Loyd vehicles proved influential in the French Army’s infantry services. On October 7th, 1930, a set of specifications was issued for a new type of vehicle. These would be véhicules blindés de ravitaillement de l’infanterie, or armored infantry supply vehicles. This set of specifications was given the denomination of “Type N” a few weeks later. The Type N specifications requested vehicles with a maximum height of 1.10 m, able to carry a load of 950 kg, typically a mortar or heavy machine gun with ammunition, crewed by two men, able to reach 35 km/h, and with an autonomy of five hours.

Projects from three different companies were ordered to be built as prototypes. The orders covered six prototype vehicles, trailers to be used by these vehicles, as well as larger trailers on which the vehicles could be carried on, towed by a truck. The first company to receive orders was Latil, which produced a design created by Brandt and Vickers-Armstrong, the makers of the Carden-Loyd. The Latil design was very similar to the original British vehicle, and one of the six prototypes was actually imported from Great Britain. The second company was Renault, generally speaking, the giant of the French armored vehicles industry in the era, which produced the UE, a small entirely tracked tankette, obviously inspired by the British Carden-Loyd but still a new design. Finally, Citroën produced the P28, a vehicle far more different from the British tankette that inspired the Type N program

Citroën’s infantry tractor

Citroën’s military vehicles of the 1920s were almost systematically fitted with the Kégresse track system. This system consisted of tracks that, instead of separate metallic interlocked parts, were instead a unitary, flexible belt. It had been created by French engineer Adolphe Kégresse whilst he was based in Imperial Russia, from 1905 onward. In 1919, Kégresse returned to France and was hired by Citroën. From then on, his track systems were featured on a large number of military vehicles, often in a half-track configuration, including artillery tractors and armored cars such as the AMC P16 (designed by Citroën but produced by Schneider) and even some Renault FT light tanks.

The vehicle presented by Citroën to match the Type N specifications was no exception to the rule. It was a small half-track with two wheels at the front used for steering and powered Kégresse tracks at the rear. These had a large front sprocket and a single bogie holding two road wheels as well as a large rear trailing wheel. A notable feature of the Citroën vehicle was that it was crewed by only one man, who sat at the front-left of the vehicle, under an openable 6 mm-thick armored hood with vision hatches on the sides. The engine was to his right; the rear of the vehicle was unarmored and featured a storage bin where weapons or ammunition would typically have been carried. The front of the P28 featured two distinctive round headlights. No armament was fitted, as the vehicle was merely intended to transport arms and ammunition under minimal protection, not to actively fight.

The driver’s hood on prototype 35248. Source: char-français

Photo of prototype 4016-W1, showing the P28’s notable headlights. Source: char-français

The engine used was a Citroën C4 4-cylinder, 72×100 1,628 cm3 engine with an output of 30 hp. This gave it a maximum speed of 39.5 km/h on-road, without a trailer. It should be noted that, when the order for prototypes was placed by the French military, the production of three half-tracked vehicles and three fully tracked ones was requested. The tracked version never left the drawing board and even its design remains unknown as of today.

Unsatisfactory trials

Three prototypes were manufactured by Citroën, registered as 35248, 35249, and 4016-W1. The first prototype began its trials at Vincennes on 24th July 1931 and continued trials there until the 29th. The two other prototypes were delivered to the training grounds along with their trailers on July 31st of the same year. The trailer that had been designed by Citroën was wheeled, unlike the Renault UK trailer of the UE, which was tracked.

Prototype 4016-W1 shown towing the Citroën trailer, and with the side hatch open. Source: char-français

Prototype 35249 with a similar trailer on a platform. Source: char-français

The vehicles generally performed quite poorly during those trials, with complaints being addressed to Citroën. Notably, the vehicle’s cooling left a lot to be desired, with risks of overheating the engine. There was no system for the driver to detach the trailer without leaving the vehicle, which was both impractical and potentially dangerous under fire. The French Conseil Consultatif de l’Armement (Consultative Council of Armament) was pushed to make a choice between the different vehicles in October 1931. While its trials had not been without flaw either, the more conventional Renault UE was adopted by the French military, cutting short the P28’s life as an infantry tractor, though not as a military vehicle in general.

Conclusion – a future in the cavalry

Despite the rejection of the Citroën P28 infantry tractor, it did see further evolution thanks to interest from the cavalry, which considered the vehicle’s potential evolution into a light reconnaissance armored car, leading to at least one of three prototypes being converted to mount a turret instead of the storage bin, and the order of 50 armored car variants of the P28 featuring a centrally-mounted turret in October of 1931.

As for the infantry tractors prototypes, their fate beyond 1931 is unknown. It is quite likely they ended scrapped, if not by the French in the 1930s, then by the German occupiers during the Second World War.

Whilst Citröen’s proposals were not adopted, they remain the most original vehicles offered to the French Army as part of the Type N program. In comparison, the Latil-Brandt vehicle was little more than a copy of the original Carden-Loyd, and the Renault UE took a lot of inspiration from the British vehicle, particularly suspension-wise.

Illustration for the Citroën P28 tractor, created by Andrei ‘Octo10’ Kirushkin and funded by our Patreon campaign

Sources

Tout les blindés de l’armée Française 1914-1940, François Vauvillier, Histoire & Collections éditions,
char-français.net
Les matériels de l’armée Française: Les automitrailleuses de reconnaissance, Tome 1, l’AMR 33 Renault, François Vauvillier, Histoire & Collections, 2005

WW2 French Prototypes

Panhard 178 with Renault 47 mm Gun-Armed Turret

Post author By Marisa Belhote
Post date April 11, 2020
3 Comments on Panhard 178 with Renault 47 mm Gun-Armed Turret

France (1940)
Armored Car – 1 Prototype Built

In 1931, the French Cavalry formulated a request for an AMD (Automitrailleuse de Découverte / ‘Discovery’ armored car), an armored vehicle meant to perform reconnaissance while having enough combat capacities to be able to engage enemy units. This was in opposition to the AMR (Automitrailleuse de Reconnaissance / Reconnaissance Armored Car), smaller vehicles with more limited combat capacities. Panhard, the leading French armored car producer at the time, designed the Voiture Spéciale 178, more often simply known as Panhard 178, to answer this request. The vehicle was adopted by the French cavalry as the AMD 35 in 1934. Formal orders were placed in January of 1935, production beginning in 1936, and the first operational vehicles delivered in February of 1937.

A Panhard 178 in service with the 6th GRDI, a reconnaissance group, during a parade, late 1930s; this may have been either in Compiègne (where the unit was formed), or in either Vitry-le-François or Bar-le-Duc, in the Ardennes, where the unit was deployed in 1939. Source: char-français

The Panhard 178 was an 8-tonne armored car powered by a 4-cylinder 105 hp engine and able to reach a maximum speed of 72 km/h. One of its most interesting features, which separated it from the vast majority of other French armored vehicles, was its two-crew APX 3 turret, which allowed the commander to concentrate on his tactical and spotting missions, leaving the operation of the gun to the gunner/loader. This was a major improvement in comparison to the one-crew turrets which featured on the vast majority of French tanks, where the commander also had to reload and operate the vehicle’s armament.

This APX 3 turret featured a 25 mm SA 35 anti-tank gun as well as a coaxial MAC 31 7.5 mm machine gun, with 150 25 mm and 3,750 7.5 mm rounds. This armament was fairly capable for an armored car, being, for example, generally sufficient to deal with early Panzer III and IV models fielded in the campaign for France, as well as the earlier Panzer I and II, with a penetration of 40 mm of vertical armor at 500 m, and 30 mm at 30° at the same distance. This gun was significantly better than the 37 mm SA 18 found on many tanks and armored cars, but the 47 mm SA 35 gun found on Somua S35 and B1 Bis tanks offered better armor-piercing capacities, as well as explosive shells which the 25 mm lacked.

The Panhard and the SA 35

Outfitting the Panhard 178 with the 47 mm SA 35 gun was considered before the campaign for France actually began. In a letter from January 1939, the French Army General Staff and the Direction of the Cavalry stated that mounting the 47 mm SA 35 gun on the Panhard armored car was a possibility, at the very least for the vehicles destined for service in North Africa. However, the same letter reported that Panhard 178 armored cars would only be outfitted with the 47 mm SA 35 gun if the production of the latter was sufficient to equip tanks being produced with the gun (the S35 and B1 Bis) and to refit the older B1 and D2 that were temporarily armed with the short-barrel 47 mm SA 34. The letter ends with the General Staff requesting the acceleration of the production of 47 mm SA 35 guns “as much as possible” from the Direction of Armament Manufacturing.

Despite the General Staff urging for more 47 mm guns to be produced in order to outfit the Panhard 178 with them as early as January of 1939, there had been little to no advance in this field by May of 1940. It is known that arming the already used APX 3 turret with the 47 mm gun was considered instead of designing a new turret. However, it was still uncertain whether the APX 3 turret could practically be modified to mount a 47 mm SA 35.

The invasion of the Low Countries and France, beginning on the 10th of May 1940, led to the Panhard 178 being fielded in large numbers against German armored vehicles, where some issues with the 25 mm SA 35 arose. While sufficient against most German-made tanks, the gun notably struggled at range, particularly against what accounts from French tankers refer to as “Škoda tanks”, most likely describing both the Škoda Panzer 35(t) and CKD Panzer 38(t). Furthermore, the gun lacked any high-explosive shell and was not automatic, making it of very little use against infantry.

At the same time, a significant problem arose in the production of the Panhard 178, hulls were being manufactured at a significantly faster rate than APX 3 turrets. While not particularly a problem during the Phoney War, as hulls could be stored while waiting for a turret, in a context where the survival of the French state was now in question, finding military use for these unarmed hulls became a priority. It is in this context that a French officer, Squadron Chief d’Astorg, who commanded the 1st RAM (Régiment d’automitrailleuses / Armored Car Regiment) of the 1st DLC (Division Légère de Cavalerie – Light Cavalry Division), unable to receive APX 3 turrets for the Panhard 178 hulls he received, requested the Renault tank design office to come up with a way to arm Panhard 178 hulls with a 47 mm SA 35 gun behind a mere gun shield instead of a fully rotating turret. This request was most likely made on 31st May 1940.

Design of the Renault Turret

Renault’s design bureau, led by engineer Joseph Restany, managed to design an entire turret within three days. The production of a prototype of this turret began immediately, with a turret being mounted on a hull on the 5th of June 1940, and went on firing trials that proved successful the next day.

Unsurprisingly enough for a turret that had been designed and then manufactured in less than a week, the design Restany and his team came up with was fairly rudimentary, particularly in comparison with the original APX 3 turret. The Renault turret was entirely welded, with a simple shape. The frontal plate, one of the distinctive elements of the design, was sloped quite considerably. It was made from two different plates, the first was 13 mm thick followed by a 25 mm one, giving a thickness of 38 mm not accounting for the slope, something which was quite respectable even for medium tanks by 1940 standards. The sides and rear of the turret were 25 mm thick. The main armament was an SA 35 47 mm gun. This gun fired 47×193 mm rimmed shells. Its standard anti-tank shell was an armor-piercing capped (APC) shell, the Obus de rupture modèle 1935, fired at a velocity of 660 m/s. According to German tests, it could penetrate 40 mm of armor at an angle of 30° and a range of 400 m. Additionally, the gun could also fire a high-explosive (HE) shell with a muzzle velocity of 590 m/s and 142 grams of explosives.

Like the APX 3 turret, the Renault one could accommodate two crew members. However, as expected because of its short design circle, it was fairly primitive. The top hatch through which the crew accessed the vehicle was reported to be “more of a lid”, and despite the rear of the turret being quite spacious, there was no rear door. Vision on the sides was provided by simple, fairly large round holes which could be closed by a rotating cover. The turret did not feature electrical traverse and therefore had to be rotated by hand.

The first prototype was not kept for experimental purposes, as is usually the case, but instead delivered to the d’Astorg’s 1st RAM as early as 6th June 1940. Accomodations for production of more examples with a slightly revised turret to offer better conditions for the crew as well as mounting a FM 24/29 machine gun in the hull began. Renault stated it could produce four turrets a day on 11th June 1940. However, the next day, the French industrial giant’s main factories of Billancourt, west of Paris, were evacuated to secondary facilities further south. This put any potential production into disarray. By the time an official order for forty turrets came on 13th June 1940, Renault was not able to fulfill it, and the single produced turret remained unique.

A photo of the 47 mm-armed Panhard 178 where it was scuttled. The top hatch of the turret is opened, and the round view port is closed. Source: Collection Pascal Danjou

Another view of the 47 mm-armed Panhard, with the turret pointed at a different angle and the side view port opened. This photo was most likely taken at a later point than the first, as suggested by the tires being removed. Source: Collection J. Beauval

Service in the 1st RAM

The hull outfitted with the Renault turret was delivered to the 1st RAM. This regiment was part of the 1st DLC, which had been engaged in the battle of the Meuse. Its men were evacuated from the vast encirclement performed by the Wehrmacht in Northern France and the Low Countries, while their heavy equipment had to be abandoned. The unit was reformed into a DLM (Division Légère Mécanique – Light Mechanized Division, in practice quite similar to a German Light Division). It was as a part of this new 4th DLM that the 1st RAM continued to fight in the campaign of France. Thanks to d’Astorg, we know about one particular skirmish in which the 47 mm-armed Panhard played a pivotal role, on 15th June 1940. Near a bridge on the river Yonne at Etigny, about 100 km south-east of Paris, a patrol led by this vehicle engaged a German motorized column including 15 vehicles escorted by two “heavy tanks” (a term which, in French testimonies from the campaign of France, generally designates a Panzer IV and occasionally a Panzer 38(t)). The Panhard 178 was able to knock out the two tanks with three 47 mm shells, allowing the patrol led by Sous-Lieutenant (sub-lieutenant) Bouhier to then knock out the rest of the German column. D’Astorg also reported that the armored car’s turret resisted multiple hits, though he does not specify whether those were hits from anti-tank weapons or merely firearms.

The 47 mm-armed Panhard met an unfortunate end shortly after this skirmish. On the morning of 17th June, the 1st RAM was attempting to cross the largest French river, the Loire, in order to defend its southern banks, where the French High Command hoped a defensive line could be formed. By the point the regiment arrived in the town of Châtillon-sur-Loire, where it was supposed to cross, the bridge had already been blown up to prevent German crossings, with all bridges south from there being unusable. Left with no other option, the unit scuttled the vast majority of its equipment in order to prevent its capture, including the 47 mm-armed Panhard. All photos we have of the vehicle show it scuttled near the railway bridge of Châtillon-sur-Loire, including some in which German soldiers pose in front of the vehicle. The fate of the vehicle beyond this point is unknown, though it is very likely it ended up scrapped.

German soldiers examining the 47 mm-armed Panhard. This photo is particularly interesting, as it shows the Panhard with its tires, in a different location, and with its inside seemingly ripped out from the door. Source: char-français

Another photo of the vehicle’s inspection by German troops. A seat is visible in the foreground, as well as the ammunition storage inside the vehicle. Source: char-français.

The Future of 47 mm Gun-Armed Panhard Armored Cars

While only a single example of this particular 47 mm-armed Panhard turret was produced, the Panhard and the 47 mm SA 35 would be mated two different times in the future. During the German occupation of France, Joseph Restany, the engineer who had designed this first 47 mm turret, was recruited by a secret organisation within the army of the Vichy regime, the CDM (Camouflage du Matériel – Material Camouflage). His job was to lead the design and production of turrets accepting both 47 mm and 25 mm guns in order to outfit them on turretless hulls which had been evacuated to Southern France and remained stored away from the eyes of the Armistice Commission. The design of those turrets would be directly based on the first model designed by Restany in 1940, though being both more advanced thanks to a longer development time, and in some others more rudimentary due to the lack of materials and the high secrecy of the project. 45 of those CDM turrets were manufactured in 1942 and installed on a variety of Panhard 178 hulls, some which would be captured by German troops during the occupation of Southern France in November of 1942 and then issued to security units operating within France.

Panhard 178 CDM in service with the German Sicherungs-Aufklärung-Abteilung 1000, a reconnaissance group of the 189. Reserve Infanterie-Division, France, 1944. All vehicles in the photo are armed with 47 mm SA 35, but it should be noted that around half of the Panhard 178 CDM received 25 mm SA 34 guns instead. Source: Christophe Grégoire collection

After the end of the occupation of France, production of yet another 47 mm SA 35 Panhard began in 1945. This new model was designated Panhard 178B, and featured the gun in a quite large, cylindrical turret, the FL1. Unlike the Renault and CDM models, which were just mounted on pre-existing hulls, new, upgraded hulls were produced alongside those new turrets. 414 of these armored cars would be produced and would be in service during the late 1940s and the 1950s. They were used for securing the French colonial empire in its last decade. In this way, despite being a single prototype rushed in June of 1940, the 47 mm-armed Panhard would have a quite significant legacy.

A Panhard 178B, the vastly modernized, 47 mm-armed model of the Panhard 178 manufactured in the late 40s for colonial service. Source: char-français

Conclusion

The 47 mm-armed Panhard 178 designed by Renault’s design office and operated by the 1st RAM is a quite peculiar vehicle when it comes to France’s armored production. One of the various improvised vehicles which appeared during the collapse of France in the spring of 1940, it is notable because, despite being a prototype, it was used operationally, and in the only instance where it is known to have fought, performed brilliantly.

The combination of the 47 mm SA 35 gun and the Panhard 178 hull is indeed one which appears full of potential. The 47 mm weapon was quite effective against tanks by 1940 and the two-crew turret featured on the Panhard 178 meant it could be operated more effectively than in one-crew turret tanks such as the S35 and B1 Bis. While the armor of the vehicle, outside perhaps of the turret’s front, left much to be desired, as on most armored cars, it retained a great mobility. While the turret manufactured by Renault in 1940 was very much experimental, the concept of a 47 mm SA 35-armed Panhard was indeed full of potential, and had even been theorized earlier. But the fall of France would prevent it from reaching its full potential and being mass-produced in a mature form, though the CDM turrets manufactured in secrecy and based on the Renault turret were one of the most extensive armament projects undertaken in Vichy France.

Illustration for the Panhard 178 outfitted with the 47 mm gun-armed Renault turret produced by Tank Encyclopedia’s own David Bocquelet.

Sources

Une entreprise clandestine sous l’occupation Allemande, Joseph Restany, Charles-Lavauzelle & Cie editions, 1948
GBM (Histoire de Guerre, Blindés et Matériel) N°86, January-February-March 2009, pp 22-31
char-français.net (1) (2)

Batignolles-Châtillon Automitrailleuse à vapeur

Renault VM Early Design Version

Jacquet Assault Train

Automitrailleuse Renault UE

Citroën P28 Chenillette

Panhard 178 with Renault 47 mm Gun-Armed Turret

France (1937~1940) Steam-Powered Artillery Tractor? – 1 Built

Full of Hot Air

Fire, Smoke, and Steam

Scalded to Death by the Steam

Sources:

France (1931) Light Armored Reconnaissance Vehicle – Design Only

Reconnaissance Vehicles and Citroën’s Successes

Creating a Reconnaissance Vehicle Using the Renault UE as the Basis

Rejection

Conclusion – A Failure which would Lead to Many Successes

Renault VM Early Design Version Specifications

Sources

France (1944) Articulated Vehicle – Design Only

The Man

Design

Suspension

Automotive

Armament and Protection

Crew

Articulation

Conclusion

Specifications – Jacquet’s Assault Train

References

France (1931-1932) Tankette / Reconnaissance Vehicle – 1 Converted

Reconnaissance Vehicles and Citroën’s Successes

A Renault UE with a Machine Gun

A Tiny Step Forward

Conclusion – The Unknown Fate of an Experiment

Automitrailleuse Renault UE Specifications

Sources

France (1931) Infantry Tractor – 3 Prototypes Built

In the wake of the Carden-Loyd

The Type N program

Citroën’s infantry tractor

Unsatisfactory trials

Conclusion – a future in the cavalry

Sources

France (1940) Armored Car – 1 Prototype Built

The Panhard and the SA 35

Design of the Renault Turret

Service in the 1st RAM

The Future of 47 mm Gun-Armed Panhard Armored Cars

Conclusion

Sources

France (1937~1940)
Steam-Powered Artillery Tractor? – 1 Built

France (1931)
Light Armored Reconnaissance Vehicle – Design Only

France (1944)
Articulated Vehicle – Design Only

France (1931-1932)
Tankette / Reconnaissance Vehicle – 1 Converted

France (1931)
Infantry Tractor – 3 Prototypes Built

France (1940)
Armored Car – 1 Prototype Built