The last Kégresses
Through the 1920s, the French company Citroën experimented heavily with military vehicles that used Kégresse suspension. This suspension was initially created by engineer Adolphe Kégresse, who was French but had worked in Imperial Russia prior to and during World War One. Kégresse returned to France in 1919 and was hired by Citroën to produce vehicles using his suspension. The Kégresse suspension consisted of a soft rubber track that had a unitary belt-type structure instead of several metallic interlocked parts. It was often used in a half-tracked configuration, including for artillery tractors but also armored cars such as the Schneider P16, which was developed during the 1920s.
The Citroën P28 was originally designed as a one-man turretless tractor, intended to carry mortars and ammunition, under the ‘Type N program’ of the French infantry, formulated in October 1930. It used an original half-track configuration, with two steering wheels at the front and a suspension using Kégresse tracks at the rear, while the two other vehicles offered for the Type N specifications were both fully tracked tankettes clearly inspired by the Carden-Loyd. While three P28 tractor prototypes were produced and tested in the summer of 1931, they did not provide satisfactory results and were not accepted by the French infantry.
The rejection of the P28 as an infantry tractor did not stop development on the vehicle though. While a program initiated and conducted by the infantry, the Type N vehicles quickly attracted interest from the French cavalry, as they were very light and quite mobile. The cavalry developed the concept of Automitrailleuse légère de contact (Light Contact Armored Car). In essence, this was a very light and only minimally armored and armed vehicle that was tasked with reconnaissance missions.
While the frame in which this was accomplished is uncertain, two variants of the P28 were modified with armament by Citroën in late 1931. It is known that no new vehicles were produced. However, whether a single vehicle was transformed twice or two prototypes were modified is unknown. These modifications, done very hastily and more for demonstration purposes than to serve as a durable, definitive vehicle. These saw the replacement of the rear storage area of the infantry tractor with a fully rotatable turret, adding an additional crew member. Two different turrets were experimented with. One was cylindrical in shape, and seemingly featured a 37 mm SA 18 main gun, similar to the gun-armed Renault FT tanks and a number of other French armored vehicles of the era. This turret was manufactured by the firm Schneider. The other prototype featured a much more rectangular-shaped turret armed with a single machine-gun of unknown model. The prototypes also had some differences in their hull design, with the driver’s hatch being extended further back than on the original tractor prototypes. Being conversions of original P28 tractors, those prototypes kept some of their elements, notably an engine to the front-right of the vehicle, in front of the turret. This prototype also retained the same engine, the Citroën C4 4-cylinders 72×100 1628 cm3 engine, with an output of 30 hp.
On 15th October 1931, a date which may have predated even the first P28 prototype being transformed, the French cavalry placed an order for 50 armored cars, though those featured a vastly modified design. They were delivered in 1932 and 1933.
The definitive P28
The P28 design which entered cavalry service in 1932 appears to have skipped the prototype stage entirely. The two first production vehicles were tested in July of 1932; one was given the C6 6-cylinders 72×100 2 442cm3 engine with an output of 55hp, and the other the K6 6-cylinders 80×100 3020 cm3 engine with an output of 67hp. This later engine was finally chosen as the definitive one for the production P28s, though issues in its development would lead to some technical issues in the first months of the P28’s service life; the vehicle finally entered regular service within the French cavalry in April of 1933.
In comparison to the prototypes, it featured a turret-mounted not on the rear of the vehicle, but instead in its center. This turret had a simple design and theoretically featured the new 7.5 mm MAC 31 machine-gun as its main armament. However, this appears to have been rarely mounted in practice, with the vehicle mostly being used for driver training. The turret had three hatches that could be opened for vision: one on the rear, and one on each side. A vision slot was also present on the front right of the turret. It had a two-part top hatch from which the commander entered the armored car.
The vehicle had a quite significantly revised hull design as a consequence of the addition of this new turret. The previously horizontal mudguards were now angled backward, somewhat similar to the tracks, though at a lower angle. The whole central armored superstructure had been redesigned to accommodate the turret, with a new two-part front hatch being designed to enable the driver to access the vehicle. The commander, who also fulfilled the role of gunner, entered through the turret hatch. Three smaller vision hatches were featured just under the turret, one frontally, one on the front left, and one on the front right. A frontal drum, similar in concept to those found on Schneider P16 armored cars, was fitted at the front of the vehicle, in order to improve crossing capacities. The P28 also had two notable, large front headlights; those were sometimes placed very far forward, very close to the drum, or further back, just in front of the turret.
The vehicle’s Kégresse suspension had a large front sprocket and a single bogie holding two road wheels as well as a large rear trailing wheel. The two front wheels were used for steering. In comparison to the P28 prototypes, the production model featured a more powerful engine that had been pushed from the right side to the back. It was a Citroën K 6-cylinders 3,020 cm3 petrol engine producing 67 hp The vehicle could, with its modest weight of 4,540 kg, reach a maximum speed of 53 km/h on a good road. It retained very modest dimensions, with a length of 4 meters, a width of 1.63 m, a height of 1.96 m, and a ground clearance of 23 centimeters. The transmission featured four forward and one reverse speed.
The vehicle’s armor had been raised to a maximum of 9 mm, however, quite shockingly for a production run of an armored vehicle, it was not manufactured using military quality steel, but instead mild steel; with a thickness of 9mm, this meant the P28 had basically no protection at all, being vulnerable to even rifle-caliber bullets. Indeed, it appears the cavalry’s P28 order was meant to be, from the start, for training purposes only while specifications for a more advanced reconnaissance armored car were being worked on (the AMR specifications being published in January of 1932).
The production P28 armored cars were delivered to French cavalry units from 1932 onward. As they served a training role, it appears they were not delivered in large batches, but instead to a variety of units in small numbers; the 1st BDP (Bataillon de Dragons Portés – Motorized Dragoon Battalion) is known to have made use of some towards 1934, for example. The vehicles appear to have been designated as AMR (Automitrailleuse de Reconnaissance – Reconnaissance Armored Car) despite their training function, with the actual role of operational AMRs being taken by the tracked AMR 33/Renault VM and AMR 35/Renault ZT.
Moderate but notable export
Despite being generally considered a mediocre vehicle, the P28 was the subject of one foreign order. In either 1933 or 1934, the Guardia Metropolitana Uruguayana, a military unit of the police of Montevideo, received three P28s which appear to have been part of the batch of fifty ordered by the French cavalry, and not built specifically for this order. Why or how the Guardia Metropolitana picked the P28 is unknown; it has been theorized the vehicles may actually have been intended to be delivered to Paraguay to reinforce its troops fighting in the Chaco war against Bolivia but may have ended up in the hands of the Uruguayan force instead of reaching their intended destination.
In any case, the P28 vehicles were put to use by the Guardia Metropolitana, and appear to have been the first armored vehicles used by the South American nation. It appears they were painted in a very light gray color. Little is known about their service life and few photos of the vehicle in Uruguayan service remain.
A lackluster French Service
In the French Army, the P28 remained confined to its training role. Despite the breakout of hostilities with Germany in September of 1939, they were typically kept as far from the frontline as possible. While it is sometimes claimed the vehicles had been retired by 1940, photographic evidence tends to show this was not actually the case; while not frontline vehicles in any way, the P28s were kept as training armored cars for the French Cavalry. A surprisingly high number of good quality photographs of these vehicles remain, which tends to be a rarity with pre-WWII French armored vehicles. Considering their less than strategically important use, it is likely the P28 armored cars were far more easily accessible to photographs and journalists than more useful vehicles.
While not meant to see combat at all, it appears that, following the disastrous German encirclement of a large part of the French army along with the British Expeditionary Force and the Belgian army in northern France, the P28 armored cars were pulled out of their training role to be used in a last-ditch effort to defend France. Desperate times need desperate measures and these wholly inadequate vehicles, just like a variety of other armored vehicles pressed into service, such as the D1 tanks urgently shipped back from North Africa, or B1 Bis heavy tanks sent into combat without their turrets. Little to no detail is known of the P28’s actions in the closing days of the 1940 campaign, but considering the vehicle’s abysmal combat capacities, it is unlikely to have performed well. Some photos do show German servicemen posing around P28s, including some which appear to have taken some damage. It is known that some were captured intact, however, unlike the vast majority of French armored vehicles, they were not pressed into German service or even given captured denominations, being entirely disregarded by the Wehrmacht; the surviving French vehicles were most likely scrapped during the war.
The Uruguayan survivor
While all French vehicles appear to have met an undignified end during the Second World War, this was not the case for the Uruguayan vehicles, which were untouched by the war. Between 1958 and 1963, the last surviving Uruguayan P28, now vastly unnecessary as the country had acquired far more potent vehicles, such as 40 M3A1 Stuarts, was put on static display at the Plaza de Armas del Instituto Militar CIGOR, a military school in Montevideo. At this point, it lost its light gray camouflage for a more military-looking green one. At an unknown date, the vehicle was then moved to serve once again as a static display in the quarters of the 4th Cavalry Regiment. The vehicle is now located at the Plaza de Armas de la Guardia de Granaderos en Montevideo. It was at some point painted entirely in an orange color with the exception of the suspension painted in light blue, but now appears to bear a more modest dark gray paint job with “GM”, for Guardia Metropolitana, painted in yellow on the turret’s front.
The Citroën P28 is one of the most often ignored armored vehicles fielded by the French military in 1940. It was an obscure half-track armored car that only offered mediocre performances and was theoretically limited to a training and perhaps propaganda role at first. However, the vehicle did end up seeing very limited combat because of the general collapse of the French military, though most vehicles appear to have fallen into German hands unharmed. They were ignored by their new owners, who appear to have promptly sent them to be scrapped.
Nonetheless, the vehicle has some interesting elements. It serves as the first armored vehicle of Uruguay, which would then go on to become a regular customer of American light tanks, acquiring M3A1s and then M24 Chaffees. The P28 is also one of the last combat vehicles using the Kégresse track system, an innovation originating from a French engineer in Imperial Russia, and which was experimented on heavily by the French in the 1920s, but somewhat fell aside, at least for armored vehicles, in the following decades, mostly because of the typical fragility of Kégresse tracks.
Tout les blindés de l’armée Française 1914-1940, François Vauvillier, Histoire & Collections éditions,
Blindados Argentinos de Uruguay y de Paraguay, Ricardo Sigal Fogliani, Ayer y hoy editions
char-français.net (https://www.chars-francais.net/2015/index.php/7-archives/de-1930-1940/1491-1931-citron-chenillette ) (https://www.chars-francais.net/2015/index.php/engins-blindes/automitrailleuses?task=view&id=793 )
Les matériels de l’armée Française: Les automitrailleuses de reconnaissance, Tome 1, l’AMR 33 Renault, François Vauvillier, Histoire & Collections, 2005
|Dimensions||4.00 x 1.63 x 1.96 m|
|Crew||Two (Driver, Commander/gunner)|
|Propulsion||Citroën K 6-cylinder petrol, 80 x 100 mm, 3,020 cm3, 67 hp at 3,250 rpm|
|Maximum speed||53 km/h|
|Transmission||4 forward, 1 reverse|
|Armament||One 7.5mm MAC 31 machine-gun (often removed)|