SOMUA S35

The vehicle was designed and manufactured by the Société d'Outillage Mécanique et d'Usinage d'Artillerie (SOMUA) and comes from a requirement from the French High Command in 1931. It was a tank for the cavalry, fast, well armed and well protected. It was the world first tank made of whole cast armor instead of bolted plates.
It entered in service with the French army in 1935/1936 and a total of 430 Somua S35 had been delivered until the defeat, they all saw action. Due to the French tactics at the time it was not used to its best effect. Many experts regarded the Somua S35, in 1940, as the best medium tank in the world. Equipped with excellent cast and sloped armor, the tank was considered hard to kill by German anti-tank gun teams as well as by German tank crews.
One other advantage was that it was able to turn on the spot because of differential steering (like on the B1bis) which allowed both tracks to go in opposite directions (without moving forward), one track was slowed down while the opposite track was accelerated.


Other unusual for the time feature concerning the Somua S35 is the automatic fire extinguishing system. Made by "Telecamit", it is made of 3 pressurized tanks containing each a litre of methyl bromide. Situated between the access hatch and the firewall and near the driver, the tanks are connected to sprinklers set around "hot "spots" (carburettors, fuel dump, fuel tanks, etc.).


Length : 5.38m
Width : 2.12m
Height : 2.62m

Crew : 3 men (Commander, driver, radio operator)
Maximum armor : 47mm
Maximum speed : 45 km/h (Somua V8 engine, water cooled, gasoline, 190 hp at 2000 rpm, up to 2300 rpm, 12700 cm3)

Transmission : 5 forward, 1 reverse
Diameter of turning circle at 6 km/h : 12m (Jentz)
Autonomy : 255 km (on road)
Ground pressure : 0.85 kg/cm² (compared to 0.73 for PzIIc, 0.92 for a Pz III e/f and 0.83 for PzIV d)

Armament : a 47mm SA35 L/32 gun (28 HE and 90 AP - traverse 360° and elevation -18 to +18°) and a coaxial 7.5mm MAC1931 in the turret (3750 rounds, RoF = 750 rpm, traverse 10° left and right and elevation -18 to +18°).

Detailed armor thickness (mm) :
Turret Front : 42mm/0° + gun and CMG mantlet (42mm)/round covering about 50% of the front surface
Turret Sides : 42mm/23°
Turret Rear : 42mm/24° (rear hatch is 42mm thick)
Turret Top : 30mm/74° and 90°
Copula : 40mm/25° and 90° (round)
Hull Front, Upper : 47mm/21°
Hull Front, Lower : 47mm/round
Hull Sides, Upper : 40mm/15°
Hull Sides, Lower : 40mm, 25mm+10mm/0° + protective skirting plates to protect the wheels
Hull Rear : 35mm/0° and 25mm/30°
Hull Top : 25mm/82° and 90°
Hull Bottom : 20mm/90°

47mm SA35 L/32 - in German service : 4.7cm KwK 173(f)


Practical AT range : 800-1000m

Ammunition :

Obus de rupture Mle1935 (APC) - in German service : Pzgr 176(f)
Caliber : 47x193R mm
Weight of projectile : 1.620 kg (sometimes 1.625 kg is indicated)
Length of projectile : 145mm (length of the case : 193mm and total length of the shell : 325mm)
V° = 660 m/s (sometimes 680 m/s is indicated)
Penetration : 40mm/30° at 400m


Obus explosif Mle1932 (HE) - in German service: Sprgr 175(f)
Caliber : 47x193R mm
Weight of projectile : 1.410 kg (142g explosive)
Length of projectile : 183mm
V° = 590 m/s


Source:
David Lehmann
Documents from Aberdeen Proving Grounds
German Documents from the National Archives
Panzertruppen