Source: Ministry of Defense of Ukraine
Starting in April 2023, the Ukrainian Army began receiving the PT-91 Twardy (“Hard”) main battle tank as part of Poland's sizable military contribution to Ukraine. In all, sixty tanks have been provided. The PT-91 is derived from the T-72M1 which is a Polish license built T-72A, the latter's production having started in 1983. Development of the PT-91 started in 1991 and the objective was to modernize the T-72M1 using as many Polish produced components as feasible in order to be as independent from imported matériel as possible. In 1993, a purchase order was placed for twenty examples for field trials and after acceptance, the first production PT-91 tanks reached Polish armor units beginning in 1998. In the photograph, the crew of a PT-91 belonging to the 22nd. Mechanized Brigade “Mykolaiv” performs repair or maintenance on the running gear.
Power for the 46-ton PT-91 comes from the S-12U, 12-cylinder, water-cooled, turbocharged diesel engine that generates 850 horsepower. Built by PZL-Wola, the S-12U is a Polish variant of the old Soviet 780 horsepower V-46-6 diesel engine. The S-12U features a updated fuel injection system along with air injection system to more efficiently burn off exhaust gases. This engine is mated to a manual transmission with an 8-speed gearbox (7 forward, 1 reverse). The top road speed the PT-91 can attain is 37 miles per hour while 264 gallons of diesel fuel give the tank a maximum operational range of 403 miles. If fitted with external fuel tanks, the operational range increases to 434 miles.
For a main armament, the PT-91 uses the exact same 2A46 125mm smoothbore gun as the T-72M1. However, the Soviet-era 2E28M 2-plane gun stabilizer is replaced with a more modern stabilizer produced in Slovakia (one of the few imported components) which is tied into the tank's SKO-1M Drawa-1T FCS (Fire Control System). The Drawa-1T FCS is a suite which includes the PCD gunner's sight, the TES thermovision night sight (developed by the Israeli company El-Op), a POD-72 commander's day/night sight, laser rangefinder, and a ballistic computer. The latter calculates the targeting requirements based on the tank's speed, the target's speed, weather conditions, the type of round being fired, and even the temperature of the round. The output is displayed on a monitor and the computer will even state when the probability of a successful hit on a target is minimal. Like the T-72M1, the PT-91 uses a automatic loader which is fed via a ammunition carousel located beneath the turret. A total of 42 rounds of ammunition are carried. This provides for a maximum rate of fire between 8 to 10 rounds per minute. The turret provides 360 degrees of traverse for the 2A46 while the gun mount offers a maximum elevation of 14 degrees and a maximum depression of 6 degrees.
The 2A46 can fire a multitude of ammunition types. An example of a APFSDS (Armor-Piercing, Fin-Stabilized, Discarding Sabot) round is the 3VBM11 which can penetrate 410mm of RHA (Rolled Homogeneous Armor) at a 0 degree slope at a range of 1.2 miles and with a 60 degree slope, the penetration is 200mm. The 3VBK27, a HEAT (High-Explosive Anti-Tank) round, can drill through 350mm of armor at a 60 degree slope out to 1.8 miles. The more standard 3VOF22 HE (High-Explosive) round can be fired out to a range of 2.5 miles. The PT-91 is not believed to be capable of using the Russian 9M119 Svir (NATO reporting name AT-11 Sniper) tube-launched, laser guided anti-tank missile.
Secondary armament includes a coaxial 7.62mm PKT machine-gun provided with 2,000 rounds and a 12.7mm NSVT heavy machine-gun fitted to a pintle mount next to the commander's cupola on the turret. A total of 300 rounds for the NSVT is typically carried.
The effective armor protection of the PT-91 and its crew of three (commander, driver, and gunner) is not specified but the standard thickness (not accounting for sloping) of the T-72M1 upon which the PT-91 is derived from sports 220mm thick front hull armor, 240mm of armor on the turret front, 200mm on the sides and rear of the turret, and up to 190mm of armor on the hull sides and rear. On the upper hull front, 16mm thick high hardness steel armor is added to boost protection. The PT-91 utilized by Ukraine are fitted with the distinctive Polish developed ERAWA-1 explosive reactive armor (ERA). It is characterized by having more squarish blocks (rather than the rectangular blocks used by the common Russian Kontakt-1 ERA) and with barely any gap between the blocks when mounted. A complete ERAWA-1 arrangement consists of a total of 394 blocks arranged on the turret, front upper hull, and sides. ERAWA-1 will not be triggered by being hit by small arms calibers nor by light cannon rounds up to and including 30mm ammunition. ERAWA, assuming it is struck by a incoming munition, offers between 95% to 100% protection against HEAT rounds from weapons such as the RPG-7. Against larger HEAT munitions, the protection is still excellent with a 65% to 70% protection versus the 125mm HEAT round and anti-tank weapons such as the Swedish AT4 (which is utilized by the Ukrainian Army). However, like any ERA, it is susceptible to defeat by tandem-charge warheads.
Other defensive systems include the PCO SSC-1 Obra-1 laser warning system. The Obra-1 consists of four sensors on the exterior of the hull and these can detect when the tank is “painted” by laser rangefinders or laser illuminators which are used most often by laser guided anti-tank missiles. These sensors are tied into a control unit with a display for the crew. In addition, the PT-91's smoke grenade launchers, 24 in all, are also tied into the control unit. When set to automatic, if the tank is painted, the Obra-1 detects the direction, warns the crew, and triggers the grenade launchers to fire and create a smoke screen between the tank and the origin of the laser. With the crew taking evasive action and the smoke degrading the laser's effectiveness and obscuring the missile operator's view, the Obra-1 offers a higher survival chance against laser guided missiles. It is possible for the Obra-1 to work semi-automatically in which the tank commander decides if the smoke grenades are launched and there is also a manual mode in which the Obra-1 simply warns of the “painting” and from what direction and the commander then has to determine which grenade launcher battery to use in addition to firing them. Besides smoke grenades, the launchers can be fitted with non-lethal tear gas grenades or fragmentation anti-personnel grenades. Further defensive equipment has the crew and engine compartments fitted with automatic fire detection/suppression systems and NBC (Nuclear Biological Chemical) protective apparatus. The PT-91 can also generate a smoke screen by dumping fuel onto the hot exhaust.
Finally, the driver's station is equipped with a US-DK-1 panel which provides the driver with full control over the tank's systems and also it can run and display diagnostic test results onto a display. For night driving, the station is equipped with a Radomka passive night sight.
As of January 2025, the Ukrainian Army has lost a total of eleven PT-91 tanks.
