JRTC VISMOD: ZSU-23-4 Shilka Russian Self-Propelled 23mm Anti-Aircraft Weapon System

The Shilka ZSU-23-4 is a Self-Propelled Anti-Aircraft Gun (SPAAG) featuring a prominent radar dish that can be folded down mounted on a modified PT-76 chassis. ZSU 23-4 Shilka, is capable of acquiring, tracking and engaging low-flying aircraft (as well as mobile ground targets while either in place or on the move). Employed in pairs 200 meters apart, 400 meters behind battalion leading elements, it is commonly used to suppress ATGM launch sites, such as TOW vehicles. The armament consists of four 23mm cannon with a maximum slant range of 3,000 meters. Ammunition is normally loaded with a ratio of three HE rounds to one AP round. Resupply vehicles carry an estimated additional 3,000 rounds for each of the four ZSUs in a typical battery. Recent (October 1997) information details ZSU-23-4 updates/modernization being offered by the Ukrainians that include: a new radar system replacing the GUN DISH radar, plus a sensor pod believed to include day/night camera, and a laser rangefinder; and mounted above radar/sensor pod is a layer of six fire-and-forget SAMs, believed to be Russian SA-18/GROUSE. The radar-guided ZSU-23-4 "Shilka" SPAAG, with its four 23 mm (0.90") autocannons, was a revolutionary SPAAG, proving to be an extremely effective weapon against enemy attack aircraft and helicopters under every weather and light condition. The ZSU-23-4 has a very high density, rate and accuracy of fire, as well as the capability for each of the four autocannons to fire its own type of projectile from separate belts. While it is technically possible that each cannon shoots different type of ammunition, there were two types commonly used in late 1970s: OFZT incendiary fragmentation and BZT armor-piercing tracer, which were to be loaded in 3:1 ratio—three OFZT, then one BZT, every 10th BZT round equipped with so-called "copper remover" and marked. Operators were strongly discouraged from shooting from a single barrel. The appearance of the "Shilka" caused significant changes in NATO tactics in aircraft use at low altitude over the battlefield. Despite its present obsolescence as a modern short-range anti-aircraft weapon, the ZSU-23-4 is still deadly for enemy light armored vehicles, infantry and firing points as an infantry-support vehicle. With its high rate of accurate fire, the ZSU-23-4 can even neutralize tanks by destroying their gun sights, radio antennas, or other vulnerable parts.[3] ZSU-23-4s, especially late models, have excellent performance and good systems reliability. Based on the GM-575 tracked vehicle chassis, which used components from the PT-76 light amphibious tank, the ZSU-23-4 mounts an armored turret holding four liquid-cooled 23 mm (0.9") 2A7 autocannons linked to an RPK-2 "Tobol" radar (NATO designator: "Gun Dish"). The vehicle weighs 19 tonnes (late modifications up to 21 tonnes), has a movement range of 450 km (280 mi) and a top speed of 50 km/h (31 mph). Additional firepower of late modifications can be supplied by a roof-mounted pod of six short-range SA-18 SAMs, or side mounted SA-16s. The crew numbers four: driver, commander, gunner and radar operator. The driver's compartment is located in the nose part of the vehicle. The fighting compartment is in the center, and the engine compartment is in the rear part of the vehicle. The transmission consists of a multi-plate metal-contact main clutch, a manual gearbox with five forward gears, two planetary two-step steering gears with locking frictions and two final drive groups. The vehicle chassis has six single rubber tired road wheels, a rear drive sprocket with detachable sprocket rings (lantern-wheel gear) and one idler wheel per side. The first and fifth left, and sixth right road wheels have hydraulic shock absorbers. The track is 11.904 m long, 382 mm (15") wide and has 93 links. Because of a large number of different pipes and tubes to detach during maintenance, the repair procedure for some of the vehicle's mechanisms is hard (for example, replacement or repair of a starter). The electric drive of an air outlet hatch of a gas turbine engine (part of the vehicle's electric power supply system) has an inconvenient location (at the bottom of the hull) which causes overheating and sometimes, jamming of the electric drive. On the other hand, the construction of the electric power supply system is very reliable. Changing the main engine oil and coolant is easy, as is replacement of fuel and oil filters, and sections of the air filter. The ZSU-23-4 can cross vertical obstacles 0.7 m (2.3') high, trenches 2.5 m (8.2') wide, has a 1.0 m (3.3') fording depth and can climb 30° gradients. The ZSU-23-4 has good maneuverability and cross-country ability, but its diesel engine's power is insufficient for a vehicle of its weight. As a result, off-road acceleration capabilities are sub-par, and the vehicle lags behind MBTs and IFVs on up-hill terrain. The ZSU-23-4 is equipped with an NBC system with an air filtration unit, fire-fighting equipment, TNA-2 navigational system, infrared vision device, R-123 radio set, R-124 intercom and electric power supply system consisting of a DGChM-1 single-shaft gas turbine engine (70 hp at 6,000 rpm) and a direct-current generator (which provides 27 V and 54 V direct current or 220 V 400 Hz alternating current).