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WW2 French Prototypes

Automitrailleuse Renault UE

Nation Flag IconFrance (1931-1932)
Armed 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.

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, named Renault UE.

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

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

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