Prototype SPG: 2S18 "Pat-S"

2S18 "Pat-S"

In the early 1980s, the new project reached the stage of construction and testing of the first prototype. During the project's implementation, the Kurgan Machine-Building Plant designers had to solve several serious technical problems, primarily those related to the strength of the structure. It was required to find a chassis capable of withstanding the recoil of a large-calibre gun or to install a cannon with a lower recoil on a new SPG.

As a result, it was possible to find the optimal combination of the base chassis and weapons, while meeting the requirements for dimensions and weight. The finished self-propelled gun with fuel, crew, and ammunition weighed about 18.7-18.8 tons, which suited the needs set by the government at the time.

 The newly developed tracked chassis of the BMP-3 infantry fighting vehicle was taken as the basis for the 2S18 SPG. The chassis was equipped with a multi-fuel 10-cylinder UTD-29 diesel engine capable of outputting 450 horsepower. With such a power plant, the Pat-S self-propelled gun could accelerate along the highway to a speed of 70 kilometres per hour and cover up to 600 km at one gas station. In addition, thanks to the BMP-3 chassis, the new combat vehicle was able to cross water bodies by swimming at a speed of up to 10 km/h.

A new rotating turret of a relatively large size was installed on the modified horizontal drive of the armoured hull. The 2A61 Pat-B howitzer developed earlier by the Sverdlovsk Design Bureau-9 was chosen as the main weapon of the 2S18 self-propelled guns. The 152-mm gun was originally created as a towed howitzer for regimental artillery, but it was also decided to use it on a self-propelled gun mount. The howitzer was modified before being installed on a self-propelled chassis, after which it received the 2A63 GRAU Index. When choosing a gun for self-propelled guns, they took into account its relatively small recoil. The fact is that initially the 2A61 howitzer was made on a modified gun carriage 2A18 (D-30), which had a smaller calibre and, accordingly, lower recoil energy. To avoid damage to the carriage structure, the new howitzer was equipped with effective recoil devices and an original muzzle brake.

The 2S18 Pat-S self-propelled artillery mount was tested and did not satisfy the military. The project was closed due to hopelessness. There are still no exact data on the reasons for the refusal of the Ministry of Defense from a promising SPG.

In the second half of the eighties, the design of a new self-propelled gun 2S31 "Vena" began. Initially, it was planned to build it on the basis of the Gvozdika chassis modified as required, but then the Pata-S chassis was chosen.