SAu 40 (CAM 2)

Serious work on a self-propelled gun intended to support infantry began in 1935, when the companies SOMUA (Société d´Outillage Mécanique et d´Usinage d´Artillerie) and ARL (Atelier de Construction de Rueil) created their designs for new self-propelled guns. SOMUA designed a pair of projects referred to as CAM 1 and CAM 2 (canon automoteur).


The SOMUA Type SAu 40 project, submitted to the French military authorities in 1937, used a modified medium tank platform Somua S 35, which was extended by 33 cm (the platform of the planned SOMUA S 40). The hull consisted of cast parts of rounded shapes. The prototype was completed (without turret and armament) in 12/1937. The armament, which was to consist of a 75 mm gun, was completed and supplied by APX. It was a modification of the 75 mm modéle 1929 de casemate fortress gun, which was to be mounted in the front of the hull. The gun had a semi-automatic breech mechanism and an automatic loading device. The weapon's range of sight was 7° to the left and 7.6° to the right, and the muzzle velocity - 10° + 30°. The secondary armament, a machine gun of 7.5 mm calibre, was located in a small turret located on the roof of the hull. The machine was powered by a 219 hp Hispano engine, which could run on several types of fuel (one of them could be e.g. aviation gasoline). The machine was equipped with an E26 ter and R61 radio set. The prototype was tested at the Bourges polygon in 1939. The tests revealed problematic loading at the front of the machine, where the weight of the gun adversely affected the stresses and durability of the undercarriage components at the front of the platform. Nevertheless, an order for 24 self-propelled guns and 12 command versions of this machine without armament was signed on 15 October 1939. The order was gradually increased to 72 self-propelled guns by 9.5.1940 (of which 24 were to be command vehicles). However, production of the main gun was uncertain, and so as an alternative solution it was proposed to replace the originally intended 75 mm calibre gun with a 47 mm calibre APX gun of the 1937 model. As of 9 May 1940, it was decided that this proposal would be accepted and all vehicles ordered were to be armed with these 47 mm guns. The design was thus transformed from a self-propelled gun to a tank interceptor.


The abandoned SAu 40 prototype was found near Compiégne at the conclusion of the fighting for France in 6/1940, when it was assigned to a provisional battle group armed with Somua S 35.

Francois Vauvillier - The encyclopedia of French tanks and armoured vehicles 1914-1940, Histoire & Collections, published in 2014, ISBN: 978-2-35250-322-4
Pascal Danjou - L´Automitrailleuse de Combat SOMUA S 35, Tracstory no.1, ISBN 2-9520988-0-8
Pascal Danjou - Juin 1940 L´Impossible Sursaut, Tracstory no.5, ISBN 2-9520988-4-0
Ivo Pejčoch - Obrněná technika 7, France 1919-1945, published by Ares, Prague 2007, ISBN 978-80-86158-47-1
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