The S-51 was a Soviet experimental heavy
self-propelled gun
Self-propelled artillery (also called locomotive artillery) is artillery equipped with its own propulsion system to move toward its firing position. Within the terminology are the self-propelled gun, self-propelled howitzer, self-propelled mo ...
designed by TsAKB.
History
At the end of 1942, the
Red Army
The Workers' and Peasants' Red Army (Russian: Рабо́че-крестья́нская Кра́сная армия),) often shortened to the Red Army, was the army and air force of the Russian Soviet Federative Socialist Republic and, after ...
switched from defensive to offensive operations, which revealed the need for self-propelled artillery. The firepower of
towed
Towing is coupling two or more objects together so that they may be pulled by a designated power source or sources. The towing source may be a motorized land vehicle, vessel, animal, or human, and the load being anything that can be pulled. Th ...
and self-propelled artillery of 152.4mm caliber was sometimes not enough against pillboxes and fortified buildings in urban battles. To solve this issue, the Red Army was armed with the towed
203 mm howitzer M1931 (B-4). However, the 203 mm howitzer was exposed and unarmored, making attacking risky. In addition, it had a low speed which made swift breakthrough of enemy lines impossible.
Therefore, the Red Army initiated a project for a heavy self-propelled gun. Plant № 100,
CB Uralmash, and
TsAKB took part in this competition. Plant № 100 under the leadership of
Josef Yakovlevich Kotin created a self-propelled gun carriage that looked similar to the
Canon de 194 mle GPF
The Canon de 194 GPF (''Grande Puissance'' Filloux - "High-Power" Filloux) - was the first French tracked self-propelled gun (SPG). Designed at the end of World War I, it was a pioneering weapon with many modern features.
Design
The vehicle wa ...
. The design by CB Uralmash was two 152mm howitzers on two connected
SU-122
The SU-122 (from '' Samokhodnaya Ustanovka 122 mm'') was a Soviet self-propelled howitzer or assault gun used during World War II. The number "122" in the designation represents the caliber of the main armament, a 122 mm M-30S howitzer. The c ...
chassis.
In the autumn of 1943, the TsAKB designed and built a self-propelled gun on the basis of the
KV-1S
The Kliment Voroshilov (KV) tanks are a series of Soviet heavy tanks named after the Soviet defence commissar and politician Kliment Voroshilov who operated with the Red Army during World War II. The KV tanks were known for their heavy armour pro ...
equipped with the 203mm howitzer. The self-propelled gun received the designation, S-51.
[
]
Description
Hull
The S-51 had a very long hull and an open topped fighting compartment. The front, side and rear of the hull had 75 mm, 60mm and 30 mm of armour respectively. The hull had a driver’s compartment and could seat one out of the 10 crews required, with the engine and transmission being located in the rear of the hull. The hull also had a bottom hatch for emergency escape and a number of small hatches for access to the other modules of the vehicle.
Armament
The S-51 was armed with a modified 203 mm howitzer M1931 (B-4). The gun was mounted at the front of the vehicle with gun shields. The elevation of the gun was 0 to +60 degrees, and the gun traverse being 4 degrees to either side. The vehicle had 12 rounds of ammunition that could be HE and/or armour piercing shells. The shells and propellant charges were placed behind the gun shields of the vehicle.[
During transport, the gun shields were let down and the barrel of the howitzer was turned to the center of the hull.][
]
Engine
The S-51 was powered by a four-stroke V-shaped 12-cylinder diesel engine V-2K. The engine produced 600 hp allowing the vehicle to travel at 35 km/h. The engine was started by a starter ST-700 with a capacity of 15 liters. Fuel tanks with a volume of 600-615 liters were located inside the hull.[
]
Transmission
Self-propelled artillery mount S-51 was equipped with a mechanical transmission. Unreliable operation of the transmission group was noted during its testing. This fact served as further confirmation of the thesis that transmission defects were one of the most significant shortcomings of the KV series tanks and vehicles based on it.[
]
Chassis
The chassis of the S-51 was identical to that of the KV-1S
The Kliment Voroshilov (KV) tanks are a series of Soviet heavy tanks named after the Soviet defence commissar and politician Kliment Voroshilov who operated with the Red Army during World War II. The KV tanks were known for their heavy armour pro ...
tank. It had 1 drive wheel, 1 rear wheel, 3 support rollers and 6 roadwheels on each side.[
]
Development
In February 1944, the S-51 underwent factory testing. It was transferred to the artillery testing ground before completing the factory tests due to the great interest in the heavy self-propelled gun project.
However, many flaws in the S-51 were discovered during the trials. When the gun was elevated to a high angle and fired, the gun would sway and the recoil would push the tank back. When the gun was elevated at a low angle and fired, the recoil would be so strong that the crew would fall over, which could be deadly in battle. Overall, it was deemed that the KV-1S chassis was unsuitable for conversions into SPGs.
Due to these problems, the S-51 did not enter mass production.[
]
References
{{WWIISovietAFVs
Tracked self-propelled howitzers
World War II self-propelled artillery
Self-propelled howitzers of the Soviet Union
Experimental self-propelled artillery
Abandoned military projects of the Soviet Union