2S4 Tyulpan

The 2S4 Tyulpan designs is based on the GM-123 chassis carrying an externally mounted M-240 240 mm breech-loading mortar on the rear of the hull. The 2S4 uses an autoloader of sort. It has two automated drum-type magazines, capable of holding up to 40 standard high-explosive rounds or 20 long range rocket-assisted rounds. The rounds are fed to the top of the carrier, where they are placed on a track. The mortar then tilts to the horizontal position. The breech opens and a ramming device pushes the round into the breech. The breech closes and the mortar tilts into the firing position. The primary ammunition for the weapon is the high-explosive 53-F-864 mortar projectile which contains 32 kg of explosive charge and has a total weight of 130.7 kg. The GMWZ-7 fuze could be set to have either a delayed action or detonate on contact. The weapon uses a 5-part propelling charge system, which vary the muzzle velocity from 158 to 362 m/s and ensure a range from 800 to 9,650 m. 1970 saw the introduction of a new type of rocket-assisted family of munitions for the M-240, designated ARM-0-3WF2 (or simply 3WF2) which used a new 4BN56 propellant charge to carry a 228 kg high explosive projectile (designated 3F2 'Gagara') to a maximum range of 18 km. Also developed was the 3O8 'Nerpa' cargo mortar round which delivers 14 submunitions fitted with fragmentation warheads which are deployed over the target by miniature parachute, as well as the 'Sayda' incendiary round. In 1983, the capabilities of the weapon were further enhanced with the development of the 1K113 'Smelchak' precision munition system which comprises a 3WF4 round with a 3F5/3W84 projectile that has a range of 9.2 km, weighs 134.2 kg and contains 21 kg of high explosive. The projectile has a seeker head which homes in on reflected laser energy, generated by ground-based 1D15 or 1D20 laser rangefinders. Course corrections are carried out in 0.2 to 3.0 s. The laser target designation system can also be linked by radio with the vehicle/mortar—and within 5 km of the target—to allow for a mode of operation whereby the laser illumination activates only once the projectile has been launched, and thus limiting the reaction time of the target and alleviating countermeasures such as laser warning devices. Such a setup makes use of the R-107 portable radio transceiver. One of the more unique aspects of the 2S4 is their nuclear capability. Development of tactical nuclear munitions for the type was initiated relatively late in the service cycle of the vehicle, in 1967, and resulted in the 3BW4 round using a 3B4 nuclear projectile with a yield of approx. 2 kt. This was improved on three years later with the development of a rocket-assisted 3WB11 nuclear round (using a 3B11 projectile with an RD-14 warhead and propelled by a 3M15 rocket motor). Development of a nuclear warhead for the M-240 was technologically limited for a period of time by the small bore of the weapon; miniaturization had only recently allowed for the reduction of the diameter of a nuclear device to a sufficiently small size so as to be used in a field artillery system. To date, the range of these nuclear projectiles has not been published, but the greater weight of such a warhead compared to the conventional mortar rounds compels experts to speculate on a lower range for such a projectile, and thus the questionable, tactical utility of the system. One of the arguments for a nuclear mortar is the fact that the nuclear device would be more reliable, since the acceleration and forces experienced by a mortar round are substantially less than that endured by a howitzer-launched projectile.

The carrier for the 2S4 was a dedicated tracked chassis also used with the 2K11 Krug TEL vehicle, and later used as the chassis for the 2S3 'Akatsiya' and 2S5 'Giatsint' self-propelled guns. Having carried out necessary modifications, this vehicle was designated Object 305. It's powered by 12-cylinder "V"-layout W-54 engine. The tracked suspensions consists of a pair of drive sprockets located at the front of the vehicle, idler wheels at the rear, six pairs of road wheels and four pairs of return rollers. The tracks are 482 mm wide each, with 115 links per tread. The vehicle is equipped with a lightweight bulldozer blade mounted to the underside of the front hull which is used for preparing dugouts for vehicle firing positions. The driver is seated on the left side of the hull, towards the front with the vehicle commander positioned directly behind him in a raised, fixed, armored cupola outfitted with vision blocks for situational awareness, and his hatch. The cupola is ringed by a skate mount that can be used to fix a PKT machine gun which can be configured to fired remotely with the crew buttoned down.

The 2S4 has a slow rate of fire, only one round per minute. This is due to the large size of the mortar and the weight of its ammunition (130 kg (290 lb) for a standard HE rounds and 228 kg (503 lb) rocket-assisted HE rounds). It can also be loaded one round at a time via a small crane, which is most often used to load the magazines or to place specialty rounds onto the loading track.

The 2S4 has a range of 9,650 meters using standard high-explosive rounds, but a range of 20,000 meters using extended range munition. In addition to the high explosive rounds, it can also fire armor-piercing, laser-guided and cluster munitions, as well as chemical, neutron and tactical nuclear rounds