ZSU-23-4 encyclopedia topics

History

The previous Soviet Union self-propelled anti aircraft gun (SPAAG), the ZSU-57-2, was armed with two 57 mm cannons, it was aimed optically using a basic tracking and lead calculating system. The ZSU-57-2 was not particularly successful; it could only carry a small number of rounds, was inaccurate, and had only limited mobility.

The ZPU series of guns were a major step forward, providing 14.5 mm heavy machine guns carried on a towed mount for stationary, point air-defence. The 23 mm version of this weapon system was known as the ZU-23-2, a towed mount carrying two 23 mm cannons.

The ZSU-23-4 "Shilka" was brought into service in 1965 and replaced all ZSU-57-2 in air defense units toward the beginning of 1970s. Initially, tank regiment should have the antiaircraft artillery battalion of "Shilka" (consisted of two batteries, four "Shilka" in each). At the end of 1960s one battery was equipped with ZSU-23-4 and another - with ZSU-57-2. Motorized rifle and tank regiments got standard antiaircraft battery consisted of two platoons later (one platoon was equipped with four "Shilka" and another - with four mobile surface-to-air missile systems 9K31 Strela-1 or 9K35 Strela-10). ZSU-23-4 "Shilka" combined a proven radar system, the non-amphibious chassis based on GM-575 tracked vehicle and four 23 mm cannons. This delivered a highly effective combination of mobility with heavy firepower and considerable accuracy. The ZSU-23-4 outclassed all NATO anti-aircraft guns at the time, and it is still regarded as posing a major threat for low-flying fixed-wing aircraft and helicopters.

The system was widely fielded throughout the Warsaw Pact, other pro-Soviet states and Middle East states (around 2,500 ZSU-23-4 from 6,500 produced were exported to 23 countries). The Soviet Union's successor states continue to manufacture and supply variants of the Shilka, notably the Ukrainian 4M4 and the Belorussian 4M5.

Shilka units saw active service in the Yom Kippur War (1973) and other Arab-Israeli conflicts, the Iran-Iraq War (1980-1988), the First Gulf War (1990), and possibly in the various Indo-Pakistan conflicts. During the 1973 Yom Kippur War, the system was particularly effective against the Israeli Air Force. Israeli pilots attempting to fly low in order to avoid SA-6 missiles were often shot down by the Shilka. During the Soviet-Afghan War "Shilka" units were used widely and to great effect against mujahideen positions in the mountains, the Shilka's guns being able to elevate to a much higher azimuth than the weapons on BMPs, BTRs, or T-55s, and T-62s. They were also used to suppress defensive positions around the presidential palace during the initial coup in Kabul at the start of the Soviet-Afghan war. Russian Army uses "Shilka" for mountain combats in Chechnya also.

Description

The radar guided ZSU-23-4 "Shilka" SPAAG with its four 23 mm autocannons was a revolutionary SPAAG representing the extremelly effective weapon against enemy attack aircraft and helicopters. ZSU-23-4 has the very high density, rate and accuracy of fire and possibility for each of four autocannons to fire its own type of projectiles from separate belts. The appearance of "Shilka" caused very significant changes in NATO tactics to use aircraft at low altitude over battlefield. Despite its present obsolescence as modern short-range anti-aircraft weapon ZSU-23-4 is still deadly dangerous for enemy light armoured vehicles, infantry and firing points as infantry-support vehicle. With its high rate of accurate fire, the Shilka can even neutralize tanks by destroying their gun sights, radio antennas, etc. "Shilka" (late models especially) has an excellent performance and high reliability of its systems.

Based on the chassis of the GM-575 track vehicle which used components from PT-76 light amphibious tank, the ZSU-23-4 mounts an armoured turret holding four liquid-cooled 23 mm autocannon 2A7 linked to an RPK-2 "Tobol" Radar (nicknamed "Gun Dish"). The vehicle weighs 19 tonnes, has a range of 450 km and a top speed of 50 km/h. Additional firepower 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 locates in the nose part of the vehicle, fighting compartment - in the middle and engine compartment locates in the rear part of the vehicle. The transmission consists of a multiplate main clutch of metallic contact, 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 roadwheels, rear drive sprocket with detachable sprocket rings (lantern-wheel gear) and idler wheel per side. The first, fifth left and sixth right roadwheels have hydraulic shock absorbers. The track is 382 mm wide and has 93 links.

Because of a large number of different pipes and tubes which should be detached during a maintenance, the repair procedure for some vehicle 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 electric power supply system) has unsuccessful location (at the bottom of the hull) which causes overheat and sometimes jamming of the electric drive. On the other hand, the construction of electric power supply system is very reliable and successful. Also the main engine oil and coolant change is easy as well as the replacement of fuel and oil filters, sections of air filter.

The "Shilka" provides a minimal comfort for the crew. Whereas the driver's compartment has a very good self-contained air pump with electric heating system, other crewmembers suffer from cold in winter because heating system of the fighting compartment (heated handrails and floor) is ineffective. It is hot inside the vehicle in summer also.

ZSU-23-4 "Shilka" can cross 0.7 m high vertical obstacles, 2.5 m wide trenches, 1.0 m fording depth and climb 30° gradients "Shilka" has good cross-country ability but its engine power is quite insufficient for the vehicle of its weight, as the result the off-road accelerating capacity is low and the vehicle gets behind MBTs and IFVs on the uphill.

Each water-cooled 23 mm autocannon 2A7 has a cyclic rate of 850-1,000 rounds per minute for a combined rate of fire of 3,400-4,000 rounds per minute. Welded turret has a race ring from T-54 medium tank with a diameter 1,840 mm. The 360° rotatory turret is fully stabilised and capable of firing on the move. The mechanisms of turret rotation and elevation of autocannons provide a very good speed and accuracy of guidance of a target, also the hydraulic drives of aiming mechanisms proved to be tremendously reliable. Quad automatic anti-aircraft gun AZP-23 "Amur" has a range of elevation from -4° to +85°. GRAU designation for ZSU-23-4 turret with 23 mm AZP-23 "Amur" quad automatic gun is 2A10.

Ammunition is 2,000 rounds stowed aboard (480 rounds per each upper autocannon and 520 rounds per each lower autocannon) in belts for 50 rounds. ZSU-23-4 can use two standard types of 23 mm projectiles: BZT armour-piercing incendiary-tracer (API-T) projectile (weight 190 g, penetrates 25 mm armour at 400 m) and OFZT (high explosive fragmentation incendiary-tracer) (HEI-T) projectile (weight 188.5 g, self-destructed in 5-11 s); each ammunition belt contains 40 OFZT and 10 BZT rounds. HEI-T and API-T rounds are fired at muzzle velocity 980 m/s. They can be fired to a maximum horizontal range of 7 km (4.3 mi), and a vertical range of 5.1 km (3.2 mi). The effective anti-aircraft vertical range is 1.5 km (0.93 mi) at a direct range to target of 2.5 km (1.6 mi) and target speed 250 m/s (up to 500 m/s if use modern fire control system). In attacking targets on the ground, its effective range is around 2.5 km (1.6 mi). The short range of its 23 mm autocannons and relatively low explosive effect of small-calibre projectiles mean it is less able to engage threats such as jet attack aircraft and cruise missiles than modern systems like the 9K22 Tunguska armed with more powerful 30 mm autocannons and integrated missile armament. A special 23 mm round with a composite projectile was developed for modern modification of SPAAG (ZSU-23-4M4) to be used against cruise missiles.

The RPK-2 "Tobol" radar operates in the J band and can detect aircraft 12-20 km away. It has excellent target tracking capability and is relatively hard to detect by the enemy. Under 60 m (200 ft) of altitude however, the radar picks up many false returns (ground clutters). The antenna of radar is mounted on collapsible supports in the rear part of turret top. There is optical alignment sight also. Regardless, pilots consider the "Shilka" to be an extremely dangerous weapons system. It is either avoided completely or engaged first. The RPK-2 radar proved to have a good protection against enemy passive electronic radar countermeasures. Nevertheless, it must be noted that the radar system of ZSU-23-4 has quite short detection range during target search which depends on weather conditions (on intensity of rain and wet-snow precipitation mainly), it is hard to autotrack the target at ranges less than 7-8 km because of high angular speed of the target at close distances. Radar needs in quite often resetting because of unstable parameters of electronic cathode-ray memory tube of the maneuverable target selection system. The absence of automatic laser rangefinder requires skillful commander and gunner.

Early versions of the ZSU-23-4 sometimes had problem with "runaway guns": after prolonged periods of firing, the guns would get so hot that chambered rounds would "cook-off" even if the human operator was not pulling the trigger, discharging the weapon and chambering a new round, which would then also cook-off, etc. This would continue sometimes until the entire belt of ammunition had been consumed. Overheating barrels could jam and even break away from the vehicle. The problem resulted from a deficient cooling system and made the early ZSU-23-4's even dangerous to the friendly troops standing nearby if this happened. Despite the fact that happened seldom Soviet operators learned to give these machines a wide berth.(Perrett 1987:100). It wasn't recommended to perform continuous fire (bursts longer than 15 sec without short pause) on earlier models until the problem with autocannon reliability and overheating during intense fire was solved on ZSU-23-4M (welded tubes of coolant outlet were replaced with flexible pipes). After the autocannon cooling system was improved, the autocannons of "Shilka" became extremelly reliable and 100% trouble-free.

ZSU-23-4 is equipped with NBC system, fire-fighting equipment, TNA-2 navigational system, R-123 radio set, R-124 intercom and electric power supply system consisting of DG4M-1 single-shaft gas turbine engine (70 hp at 6,000 rpm) and direct-current generator.

Deployment

Soviet doctrine supplied the vehicle since 1965 in a anti-aircraft artillery battalion of two four-vehicle platoons for anti-aircraft defence of motor rifle and tank regiments. In the end of the 1960s one platoon was equipped with ZSU-23-4 SPAAGs while another one was still equipped with ZSU-57-2 SPAAGs. ZSU-57-2 were completelly replaced with ZSU-23-4 by the beginning of 1970s. Later, Soviet motor rifle and tank regiments were equipped with an anti-aircraft battery consisting of two platoons, one equipped with four ZSU-23-4 SPAAGs and the other with four 9K31 Strela-1 (SA-9 Gaskin) or four 9K35 Strela-10 (SA-13 Gopher) short-range surface-to-air missile systems.

The ZSU-23-4 is very vulnerable to enemy anti-tank missiles, cannons and heavy machine guns; the armour is thin (not exceeding 15 mm) and the exposed wheels, tracks, radar, and gun barrels can easily be damaged in combat. Firing positions of ZSU-23-4 SPAAGs are typically placed near the forward edge of the battle area (FEBA) but behind the main forces, usually 600-1000m behind defended objects when on the defensive or 400-600 m behind the leading tanks on the offensive. ZSU-23-4 SPAAGs are divided evenly along the troop columns on the march.

At first each "Shilka" SPAAG operated in combat autonomously, without target marking from air defence of regimental or divisional level. In 1978, the PPRU-1 (mobile reconnaissance and control post) was passed into service of the Soviet Army. PPRU-1 ("Ovod-M-SV") vehicle based on MTL-BU armoured tracked chassis and it was intended for control of motor rifle or tank regimental anti-aircraft unit equipped with ZSU-23-4 SPAAGs and 9K31 "Strela-1M" mobile surface-to-air missile systems. PPRU-1 is equipped with "Luk-23" radar and automatic fire control system associated with the divisional air defence system.

The guns are useful against low-flying aircraft and lightly protected ground targets. Due to its effectiveness against ground targets, the "Shilka" units have been effectively used in urban environments (e.g., Afghanistan, Chechnya, Lebanon). This is primarily because of the high rate of fire of their cannons. While a main battle tank can inflict substantially more damage per round, the anti-aircraft guns can fire at a comparatively much higher rate.

Besides the Russian Army a small amount of ZSU-23-4 is still in use by Russian marines (61^st and 175^th brigades of the Northern Fleet, 336^th brigade of the Baltic Fleet).

Variants

ZSU-23-4 "Shilka" (1964): pre-production and then initial production models.

ZSU-23-4V "Shilka" (1968): modernized variant with enhanced reliability of some details, ventilation system case located on the right side of the hull. Commander vision device was added.

ZSU-23-4V1 "Shilka" (1970): modernized variant with enhanced reliability of radar system and other details, ventilation system cases located on front bilges of the turret. Guidance-system computer was improved (as well as accuracy and efficiency of anti-aircraft fire on the move at 40 km/h). Fitted with a slightly improved diesel engine V-6R-1.

ZSU-23-4M "Biryusa" (1973): armed with modernized autocannons 2A7M - pneumatic loading was replaced with pyrotechnic loading (unreliable compressor was removed), welded tubes of coolant outlet were replaced with flexible pipes which increased autocannon barrel life from 3500 rounds to 4500 rounds.

ZSU-23-4MZ "Biryusa" (Z stands for "zaproschik" - interrogator) (1977): equipped with identification friend-or-foe system "Luk". All ZSU-23-4M were upgraded to ZSU-23-4MZ level during scheduled repairs. It should be noted that army unofficially continued to use the name "Shilka" for all variants of ZSU-23-4.
ZSU-23-4M2 (1978): so called "Afghan" variant. Reequipment performed during the Soviet War in Afghanistan for mountain combats. Radar system was removed and night-sight was added. Ammunition increased from 2,000 rounds to 4,000 rounds.
ZSU-23-4M4 (1999): modernized variant developed by Ulyanovsk Mechanical Plant. The vehicle armed with two additional paired man-portable air-defense systems "Igla" (on each side of the turret) and equipped with laser emission sensors, electron-optical vision devices (including television system for driver) and improved weapon radar system. Mechanical transmission was replaced on hydrostatic transmission, hydraulic boosters were installed. Mobility increased to the level of main battle tanks. First shown on public during exhibition MAKS-99 in Zhukovsky.

Donets (1999): Ukrainian modernization developed by Malyshev Tank Factory in Kharkiv . Improved turret from ZSU-23-4 armed with two additional paired man-portable air-defense systems "Strela-10" was installed on chassis from T-80UD main battle tank. Ammunition for 23 mm autocannons increased two times.
ZSU-23-4MP "Biała" (2000): Polish upgrade, Grom anti-aircraft missiles, fully digital passive aiming devices instead of the radar.

Combat history

1968 - 1970 War of Attrition
1973 Yom Kippur War
1959 - 1975 Vietnam War, during the last years of the war
1975 - 1991 Angolan Civil War, 1st Civil War
1977 Libyan-Egyptian War
1977 - 1978 Ogaden War
1979 - 1988 Soviet War in Afghanistan
1980 - 1988 Iran-Iraq War
1982 Lebanon War
1990 - 1991 Gulf War
1994 - 1996 First Chechen War
1999 - NATO bombing of the Federal Republic of Yugoslavia
1999 - Second Chechen War
2003 - Invasion of Iraq

Users

- 20 were delivered from USSR.
- 210 in 1995. According to another sources - 310 were delivered from USSR.
- 20 were delivered from USSR.
- 27.
- 36 in 1995 (delivered from USSR).
- 350 in 1995. 330 were delivered from USSR, also a new contract was signed with Russia in 2005.
- 38.
- 131 were delivered from USSR.
- 16 were delivered from USSR.
- 20 in 1995. 14 were delivered from USSR.
- 100 were delivered from USSR.
- captured Egyptian and Syrian vehicles.
- 16 in 1995 (delivered from USSR).
- >100 were delivered from USSR.
- 35 in 1995 (delivered from USSR).
- 44. 150 were delivered from USSR.
/ - ~450 in active service in 2007 (400 are used by army and 50 by marines)
- 400 were delivered from USSR.
- 40 in 1995 (delivered to South Yemen from USSR).

References

Perret, Bryan (1987). Soviet Armour Since 1945. London: Blandford Press. ISBN 0-7137-1735-1.
Shirokorad A. "Shilka" i drugie otechestvennye ZSU ("Shilka" and Other Native SPAAGs), Bronekollektsiya, 1998, No. 2.