The basic task of a self-propelled 120mm mortar is to perform indirect, semi-direct or direct fire on enemy targets. Moreover, with special ammunition, the mortar can fulfill fire support tasks in the range of lighting and smoke screens.
HSW M120 Rak self-propelled mortar on tracked chassis (Picture source: Army Recognition)
M120 Rak is a self-propelled artillery system equipped with an automatically-loaded 120 mm mortar mounted on a tracked (SMG 120/M120G) or wheeled (SMK 120/M120K) chassis, designed by Huta Stalowa Wola (HSW). It is in service with the Polish Land Forces. Serial production and the first delivery started in 2017. Work on the Rak mortar started in 2006, the first prototypes were presented in 2009. It is constantly being refined and improved. It was initially designed by HSW, later with co-financing from the Ministry of Science and Higher Education. Most of the mortar elements are produced in Poland. HSW has received several patents for the manufacture of individual mortar solutions.
In April 2016, with the consortium of HSW and Rosomak S.A., a contract was signed for the supply of eight KMO Rak systems (64 M120K mortars and 32 artillery command vehicles (AWD)) in 2017–2019. In October 2019, another contract was signed for the supply of two KMO Rak systems (18 M120K mortars and 8 AWD) and two mortars for training at the Centrum Szkolenia Artylerii i Uzbrojenia (Artillery and Armament Training Center) in Toruń. In May 2020, the Inspektorat Uzbrojenia (Armaments Inspectorate) signed a contract with the consortium for the delivery of another 5 KMO Rak systems (40 RAK mortars and 20 AWD).
The autonomy of the self-propelled mortar turret was achieved thanks to the application of an integrated C4I-class fire and command control system (TOPAZ) enabling automatic cooperation with external fire command and control systems of this class. Its reliable operation is ensured by, among others, the inertial navigation system Talin 5000 + GPS with odometer and ballistic computer, on the monitor of which the current tactical situation is displayed on a digital map. In addition, the turret equipment includes a FONET internal communication system, an external communication system (VHF RRC 9311 AP digital radio), an optoelectronic sight for direct shooting with a thermal imaging camera and a laser rangefinder, day and night commander’s observation devices, a 360° observation system, an OBRA-3 SSP-1 laser radiation detection system, an auxiliary armament made of a 7.62mm UKM 2000D machine gun with day-night Bazalt sight system, and 81mm smoke grenade launchers.
Important and innovative solutions implemented in the M120 are the automatic mortar guidance system and the automatic loading system able to operate at 360°, with a -3 to 80° angle of fire. This enables reduction of the reaction time: the self-propelled mortar needs less than 30 seconds to set the parameters and open fire, and 15 seconds to change firing location. The maximum rate of fire ranges from 6 to 8 rounds er minute at 10 km maximum. The rotary magazine contains 20 rounds for immediate use. 26 additional rounds are stored in racks located on the chassis.
The new tracked chassis uses a hydropneumatic suspension, a system that enables changing the round clearance. The 21-ton vehicle is motorized with an MTU 6V199 TE20 turbocharged diesel engine developing 260 kW that enables a top speed of 60 km/h on a hard surface. The autonomy averages 500 km. Only three crew members are needed to operate the system.
