Russo-Ukrainian War: The ZSU-23-4M1 Shilka SPAAG

Source: front_ukrainian on X™

     In its heyday, the ZSU-23-4 Shilka (meaning “Awl”) was a much feared SPAAG (Self-Propelled Anti-Aircraft Gun) as it was far superior to all anti-aircraft guns then deployed by Western forces. The ZSU-23-4 proved its worth during the Yom Kippur War in 1973, devastating Israeli Air Force aircraft who were flying low to avoid 2K12 Kub (NATO reporting name SA-6 Gainful) SAMs (Surface-to-Air Missiles). The ZSU-23-4 was not just lethal to low flying aircraft but also against ground targets. Some NATO country military doctrines at the time stated when infantry units engaged Soviet or Warsaw Pact armored columns, if a ZSU-23-4 was present, it was to be targeted and destroyed first. This is because its four 23mm cannons could decimate infantry with ease. Eventually, the ZSU-23-4 was eclipsed by more modern SPAAGs and in Russian service, the 2K22 Tunguska was its successor. Nevertheless, despite entering service in 1962, the ZSU-23-4 remains in active service with 25 countries, including Ukraine. As such, some countries have upgraded the ZSU-23-4 to better compete on the modern battlefield. These countries include Belarus, India, Iran, the Netherlands, Russia, and Ukraine. The photograph shows a ZSU-23-4M1, one of sixteen, that were upgraded by donations made through the Come Back Alive Foundation. This particular vehicle is in service with the 13th. Operational Brigade “Khartia”, a unit within the National Guard of Ukraine. The name of the vehicle is “Alligator” (“АЛІГАТОР”) and the crew has shot down four Russian Geran-2 drones as shown by the kill markers on the hull side.

     Power for the 20-ton ZSU-23-4 comes from a V6R-1 6-cylinder, water-cooled diesel engine that develops 290 horsepower and this can push the ZSU-23-4 along roads to a maximum speed of 31 miles per hour and off-road, terrain depending, to a top speed of 19 miles per hour. 136 gallons of onboard fuel provide the ZSU-23-4 with a maximum road range of 280 miles but if moving off-road, the range drops to 186 miles.

     The ZSU-23-4 is built upon a GM-575 tracked chassis and the manufacturer in Russia was the Mytishchi Machine Building Plant. It has six road wheels per side and no track return rollers. The four man crew is protected by welded steel armor though it is not thick. The hull front and sides support 15mm thick armor while the turret has between 8mm to 9mm of armor protection. This makes the ZSU-23-4 vulnerable to most battlefield weapons. In fact, the 5.56mm M995 tungsten core AP (Armor Piercing) round can penetrate 12mm of armor at 100 meters so heavier calibers can threaten the ZSU-23-4 from much greater ranges. Other protective equipment include a overpressure NBC system and the ability to mount 81mm smoke grenade launchers. Communication equipment inside the ZSU-23-4 includes a digital R-123 system which has a maximum range of 31 miles. The driver is provided with a BMO-190 daylight periscope while the commander is provided with a TPKU-2 daylight periscope and a TKH-ITC infrared periscope.

     The sole armament of the ZSU-23-4 consists of the AZP-23 “Amur” weapon system which comprises four water-cooled 2A7 23mm autocannons. The turret provides 360 degrees of traverse while the stabilized mounting for the AZP-23 permits a maximum of 85 degrees of elevation and 4 degrees of depression. Each 2A7 autocannon has a maximum cyclic rate of fire between 850 to 1,000 rounds per minute which means with all four autocannons firing, the ZSU-23-4 can put 3,400 to 4,000 rounds per minute into the sky. In practice, 10 to 30 round bursts are fired at a time for a 400 round per minute sustained rate of fire. The reason for short bursts is because the ZSU-23-4 has a maximum of 2,000 rounds of ready ammunition (520 rounds for each top cannon and 480 rounds for each bottom cannon) and once expended, it takes 20 minutes to reload. Another reason for short bursts is to prevent barrel overheating. The effective direct fire range of the AZP-23 is 1.6 miles and a effective vertical firing range of 3.2 miles. Typical ammunition fired includes the BZT blunt steel core API (Armor Piercing Incendiary) round which can penetrate 15mm of rolled homogeneous armor at a 30 degree slope at 1,000 meters and the OFZT HE-T (High-Explosive Tracer) round. Often, the ammunition will be a mixture of AP and HE rounds to engage different target types. In addition to radar controlled automatic target engagement, the AZU-23 can be manually aimed and fired if the radar system fails or is jammed.

     The radar system in this upgraded ZSU-23-4M1 replaces the standard RPK-2 “Tobol” (NATO reporting name Gun Dish) fire control radar with a more modern set. While the specific performance parameters of the new radar have not been disclosed, a December 22, 2025 report on the website Zona Militar states that the effective radar range is “doubled” which would mean a 24 mile target detection range (the RPK-2 is 12 miles) and a tracking range of 22 miles (compared to 11 miles for the RPK-2). The ZSU-23-4's original fire control apparatus has been replaced with digital equivalents that reduces the engagement time from 12 to 18 seconds down to under 1 second. Also, the new radar permits simultaneous tracking of up to 20 targets.

Russo-Ukrainian War: Abandoned 2K22 Tunguska

     One of the more curious aspects of the war is the lack of Russian air power in the skies. In a November 2021 report from Flight International, the Ukrainian Air Force fielded 37 Mikoyan MiG-29 Fulcrum multi-role fighters, 12 Sukhoi Su-24 Fencer attack jets, 17 Su-25 Frogfoot attack/close air support jets, and 32 Su-27 Flanker multi-role fighters. Against these 98 combat aircraft (Ukraine has no bombers any longer), the Russians have arrayed at least 300 combat aircraft in the region. Yet, even now, Ukrainian pilots are still able to sortie against Russian ground targets and engage in low-level aerial combat with what Russian aviation is about in the sky.

     So why is this the case? There are many opinions out there. The first is a lack of PGMs (Precision Guided Munitions) coupled with the inability to accurately deliver said ordnance. The latter is due to inadequate pilot training. It is believed that Russia's inventory of PGMs is very low and thus if any strikes were to be carried out, it would be done with unguided bombs and rockets. By having to use such munitions, it forces the aircraft into range of Ukrainian surface-to-air missiles, especially man-portable ones.

     Another factor is the fear that Russian ground forces will shoot first and ask questions later. Considering that a decent portion of Russian troops are conscripts, this fear is very much valid. Combine this with the fact the Ukrainian Air Force flies the same exact types of aircraft the Russian Air Force does, the risk is very real and the last thing the Russian Air Force wants is lost planes due to friendly fire.

     Finally, some think that the typical Russian pilot lacks flight hours, and thus the needed skill to engage in actual combat successfully, in comparison to Western pilots. On average, a Russian pilot gets under 100 hours in the cockpit every year while, for example, U.S. Air Force pilots can get up to 240 hours each year.

     The photograph here shows an abandoned 2K22 Tunguska somewhere around Kharkiv. The 2K22 is the replacement for the ZSU-23-4 Shilka, a rather lethal self-propelled anti-aircraft gun (SPAAG) that entered service in 1960. So lethal was the Shilka that many NATO nations stated in their infantry combat doctrine that any time a ZSU-23-4 was spotted in a column being ambushed, it was to be destroyed immediately before any other target as the quadruple 23mm cannons would quickly put an end to the attack. Although the Russian Marines still deploy the Shilka, the Russian Army uses the 2K22.

     The 2K22 is built on a GM tracked chassis, powered by a V-46-6-MS turbocharged, V-12, fuel-injected, water-cooled diesel engine developing between 780 to 840 horsepower. This gives a top road speed of 40 miles per hour and enough fuel for a 310 mile operational range. The SPAAG is equipped with the Hot Shot (NATO code-name) system that combines a parabolic E-band target acquisition radar (what we see in the folded position in the photograph) with a J-band monopulse tracking radar fitted in the center of the turret front. The target acquisition radar has a 360 degree field of view, can detect aerial targets out to 11 miles and flying as low as 50 feet off the ground. It can track targets starting within 10 miles at an altitude of 2 miles or less. Engagement can occur when the target speed is 1,640 feet per second or less with the response time of the weapon systems being 6-8 seconds. The Hot Shot system is all-weather, day and night.

     Speaking of weapons, the 2K22 is fitted with two 2A38M 30mm guns with each gun provided with 1,904 rounds of ammunition. Underneath each gun is a battery of four 9M311 surface-to-air missiles (NATO code-name SA-19 Grison), for a total of eight ready-to-fire missiles. The combined fire of both cannons is 3,900 to 5,000 rounds per minute but the usual is brief bursts of 83 to 250 rounds target depending. The maximum effective range is 2,000 meters while with the 9M311, the maximum range is between 5 miles to 6.2 miles. The missiles cannot be fired while the 2K22 is on the move though the guns can when set to full automatic computer controlled engagement. If need be, the gunner is provided with a stabilized sight for manual engagement, using the radar for range data.

     The 2K22's armor protects the four man crew from small arms fire and shell fragments but it is incapable of surviving hits by anything heavier. It is well equipped with good ventilation, heating system, NBC (Nuclear Biological Chemical) system, automatic fire suppression, night vision, extensive communication equipment, and navigational systems.

     The Ukrainian Army had, in a 2012 report, 70 Tunguska on strength but built on a 2S6 chassis rather than a GM chassis. How many remain in service now is unknown. It is believed that this example may have ultimately been destroyed by Ukrainian forces. This assumes the Russians rendered the 2K22 unusable prior to abandoning it.

Originally posted on March 3, 2022.

The Flugabwehrkanonenpanzer Gepard: The Bundeswehr's Potent SPAAG

      A West German crewman of a Flugabwehrkanonenpanzer Gepard (Anti-Aircraft Cannon Tank “Cheetah”), more commonly referred to as the Flakpanzer Gepard, shows off a section of linked 35mm ammunition for the Gepard's twin 35mm Oerlikon GDF automatic cannons. The advent of the jet aircraft in the ground attack role meant that existing self-propelled anti-aircraft guns (SPAAGs) which relied on visual (optical) sighting (also called “clear weather” systems) and manual fire controls were rapidly on the road to obsolescence. The deployment by the Soviet Union of the ZSU-23-4 “Shilka” (Zenitnaya Samokhodnaya Ustanovka; Anti-Aircraft Self-Propelled System) beginning in 1965 which featured the RPK-2 “Tobol” (NATO codename Gun Dish) radar linked to its four 23mm 2A7 autocannons was something that the West had to fear as no NATO country had anything comparable. The U.S. Army did have the T249 Vigilante, a radar-controlled 37mm six-barrel rotary cannon that was capable of spitting out 3,000 rounds per minute. Mounted on a modified M113 armored personnel carrier chassis, development of the T249 started in 1956, one year prior to the start of the ZSU-23-4 program. However, by 1962, the T249 was canceled in favor of the General Dynamics MIM-46 Mauler self-propelled anti-aircraft missile system. Meanwhile, Germany commenced work on the Flapanzer Gepard in 1963 with the first four prototypes being constructed in 1969. These prototypes tested both 30mm and 35mm automatic cannons and on June 25, 1970, it was decided that the Gepard was to utilize the 35mm Oerlikon GDF guns. A year later, a further twelve prototypes were built. The Gepard was not an inexpensive piece of equipment with one Gepard having three times the price of a single Leopard 1 main battle tank (MBT). On February 5, 1973, the approval of funds for the purchase of 420 examples was given and in September of 1973, Krauss-Maffei was contracted to construct and assemble the new SPAAG. The first Gepards entered Bundeswehr service beginning in December 1976.

     The chassis of the Gepard consists of a Leopard 1 MBT hull with only a minimal of design changes. The key changes included adding more batteries, slightly increasing the distance between the third and fourth road wheel, and adding a Daimler-Benz OM 314 4-cylinder auxiliary diesel engine into a compartment that originally housed ammunition for the Leopard 1's main gun. This auxiliary engine generates 66 kilowatts and provides power to two tandem Metadyn machines linked to a flywheel which controls the turret traverse and gun elevation drives, two 3-phase 380 Hertz generators that operate the ventilation, fire control, and radar systems, and a Model 300-A 28 volt DC generator for the Gepard's electrical system. 260 gallons of diesel fuel feed the engine and provides up to a maximum of 48 hours of continuous usage. The engine is the same as the Leopard 1, being a MTU built Model 838 10-cylinder multi-fuel engine that produces 819 horsepower which gives the Gepard a maximum speed of 40mph with an operational range of 340 miles. The chassis modifications were done by Krauss-Maffei and also Porsche.

     The twin 35mm Oerlikon GDF guns and the turret were designed by Oerlikon-Bührle with the guns having a muzzle velocity of 4,700 feet per second that give an effective range of 5,500 meters. Each gun is supplied with link belted ammunition with a mixture of 320 rounds of anti-aircraft ammunition and 20 rounds of armor-piercing ammunition for a total capacity of 680 rounds. The combined rate of fire for the guns is 1,100 rounds per minute. Maximum gun elevation is 85 degrees with the maximum gun depression being 10 degrees. Fitted to the back of the turret on a retractable arm is the search radar developed by Hollandse Signaalapparaten while fitted to the front of the turret is the tracking radar, designed by Siemens. The search radar operates in the S band and has a 9 mile range while the tracking radar operates in the Ku band and also has a 9 mile range. In addition, the Gepard is equipped with a laser rangefinder. This provides the Gepard with all-weather fire-control. For self-defense, eight smoke grenade launchers are fitted to the turret, four per side. For protection, the turret has approximately 40mm of armor while the hull has between 50mm to 70mm of frontal armor, 35mm of side armor, and 25mm of rear armor. The armor type is RHA (rolled homogeneous armor).

     Today, the Gepard has been replaced in Bundeswehr service by the missile-armed Wiesel 2 Ozelot (“Ocelot”) Leichtes Flugabwehrsystem (Light Anti-Aircraft System). Brazil, Jordan, and Romania are the only current operators of the Gepard with Qatar to be the fourth with 15 expected to be in service by 2022 for anti-drone duties.

     As a note, the MIM-46 Mauler mentioned above ended up canceled in 1965. During the time of the Gepard's development, the U.S. came up with the M163 Vulcan Air Defense System (VADS) which utilized the General Dynamics M61 20mm 6-barrel Vulcan rotary cannon linked to a simple AN/VPS-2 range finder radar and M61 optical lead-calculating sight. Usage of a night vision sight allowed the M163 to have day and night firing capability. It was to work in conjunction with the missile-armed M48 Chaparral and thus between the two, short to long range engagements of enemy aircraft could be conducted. The M163 used the M113 chassis while the M48 utilized the M730 chassis, the latter a heavily modified carrier variant of the M113. In 1977, the U.S. Army started the M247 Sergeant York DIVAD (Division Air Defense) SPAAG project. Built on a M48 Patton tank chassis, the M247 was developed by Ford Aerospace and consisted of twin 40mm Bofors L/70 cannons in turret which also contained the search radar and the Westinghouse AN/APG-66 tracking radar. The entire M247 program was riddled with problems, not the least of which the M247 was built using as much “off the shelf” components as possible. Other problems included an easily jammed electronic counter-countermeasures (ECCM suite), the inability of the M247 to keep pace with the M1 Abrams MBT, a turret which turned too slow to engage fast moving targets, a tracking radar which was incapable of detecting targets from ground clutter and had a slow reaction time, and huge cost overruns. After 50 vehicles were built, the entire project was canceled in August 1985. In the meantime, the U.S. Army kept on using the M163 and M48 Chaparral into the 1990s before the introduction of the M6 Linebacker and later, the M1097 Avenger.

The 8.8cm Flak 41 (Sf) mit Panther I Bauteile: Drawing Board Flakpanzer

Armin Hage's excellent model of the proposed 8.8cm Flak 41 (Sf) mit Panther I Bauteile.

     If one examines the many German self-propelled anti-aircraft guns (SPAAGs) produced or designed during World War Two, two of the production medium tank chassis were utilized for mounting anti-aircraft guns and these were the Panzerkampfwagen PzKpfw IV, and not surprisingly, the PzKpfw V Panther. Of the two, the PzKpfw IV had the only SPAAG variants that saw production and combat use and these included the Möbelwagen (single 3.7cm FlaK 43), Wirbelwind (four barrel 2cm Flakvierling), and the Ostwind (single 3.7cm FlaK 43). Several experimental designs emerged as well, to include the Gerät 556 (Kugelblitz) armed with twin 3cm MK 108 cannons, a variant of the Möbelwagen mounting the same 2cm Flakvierling as the Wirbelwind, the Ostwind II equipped with two 3.7cm FlaK 43 guns, and the Flakpanzer IV (Zerstörer 45) armed with the four barrel 3cm Flakvierling 103/38. All of the experimental PzKpfw IV SPAAG designs made it to at least a single working prototype. The same cannot be said at all for the SPAAG variants of the Panther.

     The image shown here displays a nicely done “what if” model by Armin Hage of the first of what would become several Panther based SPAAG designs. The vehicle had the very long name of 8.8cm Flak 41 (Sf) mit Panther I Bauteile which translated as 8.8cm Flak 41, Self-Propelled, with Panther I Components. The designer was Rheinmetall-Borsig and the first draft of the new SPAAG was completed by October 24, 1943. As the name suggested, the basis of the vehicle was the Panther already in production. Thus, it kept much the same components to include the suspension, drive train, driver controls, AK 7-200 transmission, and the Maybach HL 230 engine. There was one major change and that was a lengthening of the chassis due to the expansion of the wheelbase to 13.2 feet. The standard Panther had a wheelbase of approximately 12.9 feet. The draft drawings showed that the on each side of the hull were two outriggers so that once the SPAAG was in position, all four outriggers would be deployed to provide for the stability of the gun platform. In addition, Rheinmetall-Borsig envisioned that the Flak 41 gun could be removed from the turret and placed onto the ground and utilized in the more traditional manner. This had some precedent as Rheinmetall-Borsig had an experimental design using the PzKpfw IV chassis which was fitted with a 10.5cm leFH 18/40 field gun mounted in a rotating turret in which the gun could be dismounted. In fact, the trailing arms and the wheels for the field gun were carried on the rear of the hull.

     Rheinmetall-Borsig struggled with the turret design and a report dated January 13, 1944 showed they still had not satisfactorily come up with a workable turret. In any case, it was the end of the 8.8cm Flak 41 SPAAG as on that same day, German military planners decided that the idea of mobile heavy anti-aircraft guns accompanying tanks was flawed. The main flaw was that heavy guns like the Flak 41 were designed to combat high flying aircraft, not low flying fighters or fighter-bombers seeking to attack tank columns. Such guns simply did not have the rapid fire capability nor the ability to quickly track fast moving targets. In addition, it was surmised that regular flak batteries would be able to handle the high flying bombers while smaller caliber cannon would be better suited against low flying aircraft. This, then, was the emphasis for the PzKpfw IV SPAAG developments and the Panther chassis was to be the backup if the PzKpfw IV was not viable. As discussed earlier, three models of SPAAGs derived from the PzKpfw IV were put into production and issued to panzer divisions as part of their anti-aircraft unit composition. Various designs were put forward using the Panther chassis, armed with varied turrets and weapon fits as small as the 2cm MG 151/20 autocannon up to the 5.5cm Gerät 58 gun. Only one design, the Gerät 554, better known as the Flakpanzer “Coelian”, advanced to a mock-up stage when the 1:1 scale wooden mock-up of the Flakpanzer 314 turret with twin wooden 3.7cm gun barrels was fitted to a Panther Ausf D chassis. As for the 8.8cm Flak 41 (Sf) mit Panther I Bauteile, all that that we know of it comes from the existence of single wooden model that was constructed by Rheinmetall-Borsig during the design phase.

     There are no known specifications for the 8.8cm Flak 41 (Sf) mit Panther I Bauteile such as dimensions, performance, and the like. Assumptions can be made but they would be merely that, guesswork. We do know the performance of the Flak 41, which, in its towed form, used a horizontal semi-automatic sliding block with rounds being electrically fired. The gun's elevation was 90 degrees with a maximum gun depression of 3 degrees. With a muzzle velocity of 3,281 feet per second, the maximum ceiling was 9.3 miles, an effective ceiling of 6.6 miles, and maximum horizontal range of 12.2 miles.