The PT-91, WR-40, Newa SC, and ZSU-23-4MP: Poland’s Upgrades to Soviet Gear

The Polish PT-91 main battle tank is a modernized version of the T-72.

The Polish PT-91 Twardy main battle tank is a modernized version of the T-72.

Often times, mainstream coverage of military equipment focuses on flashy new weapon systems, such as the F-35 fighter jet. Based on these prominent articles and the formidable budgets of many militaries, it would be a natural assumption that militaries regularly replace their old gear with cutting-edge technology. However, this is far from the case. Even best-funded militaries tend to retain large amounts of fairly antiquated gear because purchasing new equipment is expensive. For example, the US’s frontline main battle tank, the M1 Abrams, has been in service for over three decades. The F-15 Eagle fighter jet, which is still undefeated in air-to-air combat, has been in service for forty years and will serve for many more. In fact, the average military vehicle has been in service far longer than the average civilian car.

This is because military systems are phenomenally expensive, not only to purchase but to develop. As a result, many nations opt to upgrade their existing equipment with new features instead of purchasing new gear. Common upgrades include the addition of modern electronics, survivability measures, lightweight materials, etc. In many cases, these upgrades can bring a piece of obsolete equipment back into the 21st century at an appealing price point.

The Polish defense industry, in particular, exemplifies this practice. After the collapse of the Soviet Union and the Warsaw Pact, Poland joined NATO. Unlike many other European nations, Poland maintains high defense spending, and so the Polish military was able to retain much of its Soviet gear for future use. However, little of this equipment was up to NATO-standard. The Polish government decided that, instead of replacing all of its Soviet gear with a pricey Western equivalent, a hybrid approach would be taken. Poland purchased some new systems, such as German Leopard tanks and American F-16 jets, from fellow NATO nations. However, Poland also retained large quantities of Soviet gear. Poland’s indigenous defense industry produces new equipment but also extensively upgrades these old Soviet systems.

Cost-effectiveness is not the only reason Poland opted to upgrade much of its old equipment instead of producing a replacement. The reality is that, in most cases, Poland’s arms industry was not capable of producing a modern replacement for its Soviet equipment. As noted, designing new military systems is a demanding task, and Polish factories in the 1990s had neither the skill nor the resources to produce clean-sheet main battle tanks or integrated air defense systems. This was partially the result of how the Warsaw Pact functioned: Poland did have some indigenous manufacturing, but big-ticket items were usually designed in either the Soviet Union or the Ukraine and then sold or given to the other Soviet satellites. As a result, Poland’s defense industry did not have experience producing advanced systems for itself, so upgrade programs were used to give work to these defense firms. This is not an unusual situation: when offering a contract, most governments consider not only the effectiveness of each proposal but also the effects it will have on the indigenous defense industrial base. The extent to which a nation’s government should shelter its own defense industries from competition is hotly debated in many nations.

Without further ado, it is time to delve a bit deeper into each of Poland’s major upgrade programs. This article will focus on Polish armored land vehicles which have Soviet underpinnings.

PT-91 Twardy

A Polish PT-91 maneuvers during an exercise.

A Polish PT-91 maneuvers during an exercise.

A T-72 tank. The PT-91 is an upgraded version of the T-72.

A T-72 tank. The PT-91 is an upgraded version of the T-72.

The Soviet Union was famous for its tanks. The T-72, which can still be found in service among dozens of armies worldwide, was one of the most successful Soviet tanks. Poland received many T-72s, which it inherited when the Warsaw Pact and the communist Polish government collapsed. While advanced for its time, the T-72 was showing its age by the 1990s. Indeed, in the Gulf War, several tank battles occurred in which (heavily upgraded) American M1 MBTs routed Iraqi T-72 formations. Relative to modern Western tanks of the time, the T-72 was poorly armored, technologically obsolete, and lacking in firepower.

To address these shortcomings, Poland developed an upgrade package for the T-72 called the PT-91 Twardy (Twardy means “hard” in Polish). The most visible component of the upgrade is the addition of explosive reactive armor (ERA) bricks to the T-72. Russia itself produces an ERA package for the T-72, Polish T-72s were not equipped with Russian ERA. Poland’s ERA blocks differ slightly in design from their Russian equivalents.

The PT-91’s usage of ERA, which is merely affixed to the surface of the T-72’s armor, affords the PT-91 increased survivability without the need to outright replace the T-72’s hull armor. However, while ERA can do much to augment the protection level of the PT-91, it cannot make up for the lack of base armor inherent in the T-72 platform; modern Western MBTs such as the M1A2 Abrams and the Leopard undoubtedly have superior protection to a PT-91, largely because they were designed from the ground up as exceptionally well-armored vehicles.

As well as the survivability upgrades, the PT-91 has an extensively modernized optics and fire control package. Additions include a thermal sight, a new stabilization package, and a modern digital fire control system. These upgrades address a major deficiency revealed in the Gulf War: non-upgraded T-72s were almost always the hunted as opposed to the hunter, largely because their optics and electronics were vastly inferior to modern Western MBTs. While optics are not the most flashy tank component, they are arguably as important as gun performance and armor levels. After all, a tank cannot engage what it cannot detect, and without the ability to effectively assess battlefield conditions, tanks quickly fall prey to anti-tank missile teams or other tanks. Similarly to the ERA package, the electronics PT-91 electronics upgrades are relatively non-invasive and do not require any major alterations to the T-72’s chassis.

In the end, over 200 T-72s were upgraded to the PT-91. The PT-91 forms the backbone of Poland’s modern armor force along with Leopard MBTs purchased from Germany. Poland has also produced other vehicles based on t he PT-91’s chassis. The around 100 T-72s still in Polish service are being phased out.

WR-40 Langusta

WR-40s during a Polish military parade.

WR-40s multiple rocket launchers during a Polish military parade.

Venezuelan BM-21 Grad multiple rocket launchers during a parade.

Venezuelan BM-21 Grad multiple rocket launchers during a parade.

The Warsaw Pact also had a noted affinity for rocket artillery. One of the most prolific examples is the BM-21 Grad multiple rocket launcher, which was introduced in 1963. The Grad is a truck-based system capable of unleashing deadly salvos of 122mm rockets. However, the original Grad design is lacking in the automation department; the launcher itself is laid manually with turnwheels and accuracy is low. The Grad launcher’s lack of an electronic fire control system to handle ballistic calculations negatively impacts accuracy, and the low automation levels of the Grad system increase the time it takes to emplace and aim the weapon.

The WR-40 Langusta is a deeply modernized BM-21. Unlike the PT-91 Twardy, the WR-40 upgrade improves not only the weapon and electronics but the whole entire chassis. As such, the WR-40 is less of an applique upgrade and more of a total overhaul of the original BM-21 setup. The upgrades address the Grad’s aforementioned shortcomings by replacing the manual aiming equipment with a Topaz automated digital fire control system. The Topaz is capable of rapidly incorporating targeting information and ambient conditions into the firing solution. Topaz also automates the laying of the launch tubes, decreasing response times and increasing accuracy.

The original Ural launch platforms are replaced with a modern Polish P662D.35 6×6 truck chassis, which is armored and offers increased mobility relative to the original configuration.

Newa SC

A quadruple Newa SC launcher unit based on a T-55 chassis.

A quadruple Newa SC launcher unit based on a T-55 chassis.

A static quadruple S-125 launcher.

A static quadruple S-125 launcher.

The News SC is based on the S-125 Pechora, a relatively old Soviet surface-to-air missile (SAM) system. The S-125, like many Soviet systems, was advanced for its age but was not upgraded rapidly enough to keep pace with advances in air defense. One of the main issues facing the S-125 is its obsolete electronics. The analog electronics used on the S-125 were bulky and highly vulnerable to jamming and electronic countermeasures, making the system almost useless in a modern conflict against a high-tech adversary.

The original S-125 system also had severe mobility issues. S-125s were launched from static emplacements or trailers, both of which had to be emplaced prior to firing; radar systems and command and control units also had to be set up prior to use. As a result, the S-125 complex took hours to emplace or relocate, so S-125 batteries were essentially sitting targets and were easily eliminated by either cruise missiles or enemy aircraft. The vulnerability of analog static SAM systems was demonstrated when first Israel and then the United States repeatedly eliminated the air defenses of various Middle Eastern countries from the 1970s to the 1990s using a combination of countermeasures, low-flying strikes, and cruise missiles to overcome largely obsolete air defense networks, many of which included the S-125.

The Newa SC upgrade changes many aspects of the S-125 system in order to increase mobility and simplicity. First of all, it eliminates the need for a large number of auxiliary vehicles by modernizing componentry. For example, instead of a separate command and control unit, the Newa SC system has a combined radar and command vehicle. Like both the PT-91 and the WR-40, the Newa SC’s antennas and electronics are all improved with the introduction of solid-state digital componentry, which increases accuracy and resistance to electronic countermeasures.

One of the most distinctive features of the Newa SC is its unique transporter-erector-launcher, which is based on a T-55 tank chassis. Unlike the static S-125 launchers, the Newa SC launcher is fully mobile and can relocate rapidly to increase survivability. The chassis portion of the launch vehicle is armored. Each Newa SC launcher carries four missiles. One byproduct of the modernized electronics is that Poland no longer has to purchase obscure analog spares from Russia.


A ZSU-23-4MP. Note the box-shaped missile launcher mounted at the rear of the turret.

A ZSU-23-4MP. Note the box-shaped missile launcher mounted at the rear of the turret.

ZSU-23-4s during a Peruvian military parade. Note the large grey radar antennae, which ZSU-23-4MPs lack.

ZSU-23-4s during a Peruvian military parade. Note the large grey radar antennae, which ZSU-23-4MPs lack.

The original ZSU-23-4 self-propelled anti-aircraft gun can be found in conflict zones across the world. The ZSU-23-4 has four 23mm automatic cannons mounted to a rotating turret. While potent in certain circumstances, the ZSU-23-4 has a markedly short aerial engagement range, a problem which is exacerbated by its lack of missile armament. Because of this, the ZSU-23-4 is usually used against helicopters and ground targets but lacks the capability to effectively engage high-performance jets. Indeed, ZSU-23-4s in modern times tend to be used not against aircraft but rather against infantry, and many examples no longer have their original radar antennae. As is the case with most Soviet Cold War-era equipment, the ZSU-23-4 lacks modern electronic systems.

The ZSU-23-4MP is a modernized Polish version of the classic ZSU-23-4 design. Perhaps the most notable addition is that of four GROM SAMs, which have twice the range of the autocannons. The autocannons are also capable of firing a new sub-calibre ammunition for increased range. Unsurprisingly, the electronics and fire control systems of the ZSU-23-4 are also upgraded. The ZSU-23-4MP’s guidance system is completely reworked; instead of a radar set, the ZSU-23-4MP uses passive electro-optical guidance, including thermal cameras, to direct its gunfire. This significantly increases the ZSU-23-4MP’s survivability, as radar emissions are easily detected. Engineers also reduced the ZSU-23-4’s thermal and electromagnetic signature.

In conclusion, there are many common trends among the Polish upgrade programs. While the level of modernization varies, from the PT-91, which retains most of the original chassis, to the WR-40, which completely reworks most components including the chassis. However, no matter the level of modernization, these programs always address shortcomings in electronic systems, which goes to show the value placed on automation and networking on the modern battlefield.

Despite the compelling benefits of such upgrade programs, there are drawbacks as well, mainly in terms of capabilities; after all, upgrades can only accomplish so much, especially when many flaws of an older system may derive from fundamental attributes that are impossible to fix with an upgrade. For example, upgrades such as the WR-40 cannot address the poor range of the BM-21’s basic missile design, and the PT-91 upgrades do not remedy shortcomings in the T-72’s base armor. This may be why none of the aforementioned systems has been met with great success in the export market. Whether sales will pick up in light of recent events remains to be seen. Nevertheless, the upgrade programs appear to have made sense for Poland, considering its need to supply factories with work as well as its abundance of Soviet equipment in need of a new lease on life. In the end, it is important to remember that defense decisions are based not only on capabilities but also on cost and industrial base decisions, all of which were likely at play here.

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