Editing AMR 33 (section)

==Projects and variants==
===AMR 33 TSF===
In 1934, the three command vehicles of the 4e GAM and 18e Dragons of 4e DC were rebuilt as AMR 33 TSF (''Télégraphie Sans Fil'' or "wireless") by fitting them with an ER29 radio set, the antenna of which was placed on the left rear corner of the hull. It is unknown whether any other command tanks were so modified.<ref>{{harvnb|Vauvillier|2005|p=43}}</ref><ref>{{harvnb|Vauvillier|2005|p=47}}</ref>

===Modernisation===
In 1934, it had already become obvious that Renault had been right in advising the selection of a different suspension type. The standard one proved to be much too flimsy and very maintenance intensive, especially the oil shock dampers. Both the three vehicles built in 1935 and the two rebuilt prototypes were therefore fitted with an improved AMR 35 suspension type with rubber cylinders.<ref>{{harvnb|Vauvillier|2005|p=27}}</ref> Prototype 79758 had been used to test three different systems: the first with the trailer wheel touching the ground, the second with five road wheels and the last, which was the one selected.<ref>{{harvnb|Vauvillier|2005|p=22}}</ref> The second type would form the basis for the Renault ZB, a lengthened export version, destined for [[China]]. It was more lightly armoured at 9&nbsp;mm and had a 65&nbsp;hp engine. Twelve were ordered in 1938, six with a 13.2&nbsp;mm machine gun and six with a 37&nbsp;mm cannon.<ref>{{harvnb|Vauvillier|2013|p=74}}</ref>

After continuing reports regarding the unreliability of the matériel – often ascribed to the fact that half-trained conscripts were the most frequent users rather than professional drivers – it was decided to investigate whether structural changes had to be made. Accordingly, the type was again tested by the Commission de Vincennes between 8 September 1936 and 5 May 1937. The commission concluded on 17 February 1938 that the suspension was fundamentally unsuited for cross-country driving and advised that all existing vehicles be fitted with a new system.<ref>{{harvnb|Touzin|1979|pp=50–51}}</ref> When war broke out, it was decided to improve readiness by fully revising all AMR 33s. During that process, they were to be refitted with the new suspension.<ref>{{harvnb|Vauvillier|2005|p=27}}</ref> About half a dozen vehicles had been so modified on 10 May.

===Type M===
Late in 1932 – this is known by a later confirming letter dated 18 December 1932 – Renault had a meeting with General Weygand, during which he proposed to develop an entire family of light armoured fighting vehicles based on the AMR 33-chassis. He was especially interested in producing a ''Voiture légère de transport de personnel'', an [[armoured personnel carrier]] capable of transporting four to five infantrymen and having a crew of two and a 19 CV engine. As there was an insufficient budget to equip even a limited part of the Infantry with fully tracked vehicles, this plan was abandoned. However, on 20 March 1933, Renault received an order from the STMAC (''Section Technique des Matériels Automobiles de Combat'') to develop a prototype of a different design discussed with Weygand: a command vehicle corresponding to the specifications of 9 January 1931 for a so-called ''Type M''.<ref>{{harvnb|Vauvillier|2005|p=33}}</ref>

In September 1933, two prototypes were presented in [[Mailly]], which were rebuilt with a more powerful 22 CV engine in 1934. In January 1934, it had been decided to order ten of these, but to use the chassis of the AMR 35 instead. The second prototype would be used in the autumn of 1936 to develop the Renault YS artillery observation vehicle, the production vehicles of which would, however, also be based on the AMR 35 chassis.<ref>{{harvnb|Vauvillier|2005|p=33}}</ref>

===Engin P===
On 9 January 1931, the French Artillery officially issued the specifications for a ''Type P'', which was to be a ''véhicule antichar'', a [[self-propelled gun|self-propelled antitank-gun]], that was to serve in the [[Maginot Line]] as a [[tank destroyer]]. On that date, Renault, who had been informed of the plans about a year earlier, had already begun to develop a prototype. The first plans foresaw a very small tracked vehicle, a ''chenillette'', weighing no more than 1.5 metric tonnes, on which a 25&nbsp;mm antitank-gun was to be mounted on a tripod in an open position. The gun would have to be removable, so that it also could be placed on the ground after having been transported by the vehicle.<ref>{{harvnb|Vauvillier|2005|p=34}}</ref>

However, the same year, it was decided to let the 25&nbsp;mm gun be towed by the Renault UE ''chenillette'', making the Type P redundant in its original scope. The Artillery therefore decided to mount, under armour, a much more powerful [[AC 37 anti-tank gun|37&nbsp;mm Modèle 1934 fortress gun]] with a [[muzzle velocity]] of 860&nbsp;m/s, which yet had to be developed by the ''Atelier de Puteaux'', the State armament arsenal.<ref>{{harvnb|Vauvillier|2005|p=34}}</ref>

In 1932, Renault delivered a prototype, a specially built chassis (N° 81805), that in general form resembled the standard AMR 33 but lacked a turret and had a raised hull roof. In the middle of the front of the superstructure, there was room for a gun; to the left of it, the driver was to be seated. Almost all available space was then occupied; this was solved by letting the gun loader sit on the floor, with his outstretched legs below the gun breech. In this cramped position, he was supposed to load the weapon, taking rounds with his right hand from a stock of 107 shells that had been positioned on the left back of the hull, where in the standard AMR 33 the back exit hatch was located. The third crew member, the commander, sat on the right, squeezed between the hull roof and the engine; he had hardly any headroom.<ref>{{harvnb|Vauvillier|2005|p=34}}</ref>

The Puteaux workshop only finished the prototype, now named the ''Engin P'', in the spring of 1935. After the gun was placed, the ''Engin P'' weighed 4565 kilogrammes and had a maximum speed of 54.1&nbsp;km/h. On 18 April 1935, the CEMAV (''Commission d'Expériences du Matériel Automobile de Vincennes''), after testing, expressed a very negative opinion: "An ancient and outdated model [...] incapable of rendering serious service". Moreover, on 24 June, the ''Conseil Consultatif de l'Armement'' decided that in future all guns up to a calibre of 47&nbsp;mm would have to be towed by the Renault UE after modifying the latter type (though this in fact never happened). As a result, the ''Engin P'' was rejected.<ref>{{harvnb|Vauvillier|2005|p=35}}</ref>

===Renault YI===
[[File:D50-12 Nr 601 (f) (1941-01-02) leichter Artillerieschlepper R 601 (f) - Tracteur d'artillerie Renault Y I (Bild).png|thumb|Renault YI]]
In the years 1932 and 1933, Renault developed a series of three unarmoured military caterpillar tractors. The smallest of these, the ''tracteur de 2 tonnes'', which had the factory designation Renault YI, largely used the AMR 33 suspension, though the sprocket was not spoked but consisted of a single convex plate. The vehicle had an open cargo room behind, the engine in front and the cabin in between. The French Ministry of War ordered two Renault YI.<ref>{{harvnb|Vauvillier|2005|p=33}}</ref>

===The Trench-Jumper===
AMR 33 prototype N° 78758 was used in 1935 by the engineer [[Nicolas Straussler]], a former citizen of [[Austria-Hungary]] who at the time lived in the [[United Kingdom]], to demonstrate his hydraulic "Trench-Jumper" that he already had tested in England.<ref>{{harvnb|Touzin|1979|p=51}}</ref> He had proposed the system to the French Army in 1933 and the ''Atelier et Chantier de la Loire'' had obtained an example. The contraption consisted of two large hydraulic arms that were to be fitted on the front and back of a vehicle. The arm in front would secure itself on the opposite bank of a trench to be crossed, preventing the tank from falling in. The tank would then drive over the trench, folding the forward arm, while the back arm would lodge itself on the bank of departure and unfold, pushing the vehicle safely across. In this way, a trench two metres wide could be crossed.<ref>{{harvnb|Vauvillier|2005|p=21}}</ref>

The system was tested on 3 April 1935 and 21 March, 30 April and 4 May 1936 and finally in March 1938. It proved to be quite effective but in 1938 the ''Commission de Vincennes'' rejected the project as the small gain in trench-crossing capacity did not make up for the higher weight.<ref>{{harvnb|Touzin|1979|p=51}}</ref>

===Smoke-laying tank===
In 1938, a smoke-laying system was tested using the AMR 33. An AM5 apparatus was fitted by the ''Chaubeyre'' factory. It was not taken into production,<ref>{{harvnb|Touzin|1979|p=51}}</ref> despite a favourable report by the ''Section Technique de la Cavalerie''.<ref>{{harvnb|Vauvillier|2005|p=21}}</ref>