PT - 91 Twardy The PT - 91 " Twardy " ( " tough " or " resilient " ) is a Polish main battle tank . It is a development of the T - 72M1 and first entered service in 1995 . The PT - 91 was designed at the OBRUM ( " OBRUM " for " Ośrodek Badawczo - Rozwojowy Urządzeń Mechanicznych " – Polish for " Research and Development Centre for Mechanical Appliances " ) and is produced by the Bumar Łabędy company - part of Polish military consortium - Bumar Group . Changes from the T - 72 include a new dual - axis stabilized fire - control system , reactive armour , a more powerful engine , transmission and new automatic loader . History . In the late 1980s the Polish Army modernized all of its obsolete T - 55 tanks to the T - 55AM " Mérida " standard . The successful conversion convinced the General Staff that similar modernization could also be applied to other Soviet - designed tanks made in Poland and used by the Polish Armed Forces . In late 1988 it was decided to prepare a project of modernization for the T - 72M1 design - using the experience from production of licenced T - 72M ( obiekt 172M - E3 - Polish army designation T - 72 ) , T - 72M1 ( obiekt 172M - E5 ) , T - 72M1K ( Polish army designation T - 72M1D ) . The Gliwice - based " Research and Development Centre of Mechanical Systems " OBRUM ( ) was chosen as the main design bureau . However , initially the work progressed at a very slow pace , mainly because the Polish General Staff was also considering the purchase of a newer version of T - 72 ( T - 72 S ) or the modern T - 80 . After the political changes of 1989 and the dissolution of the Soviet bloc , Polish - Soviet talks on purchase of modern tanks came to a halt and the design of a new Polish tank gained momentum . The first design proposed by the bureau was code - named " Wilk " ( Polish for " wolf " ) , but the project was cancelled . Instead , the priority was shifted to a different project named " Twardy " . The basic aim of the conversion of T - 72 was to adapt it to the reality of modern warfare and fix its most visible deficiencies . Among those were low mobility , insufficient armour , lack of a fire control system and poor stabilisation of the main gun , which resulted in poor firing accuracy . An additional problem was lack of passive night vision aiming systems . Development . Starting from July 1991 T - 72 modernization programs were implemented by the Bumar combine which had been producing T - 72 s under Soviet license . The modernized main battle tank was designated PT - 91 " Twardy " . From base modification it differs in increased defense , fire control system and engine . In 1993 the Polish Defense Ministry ordered 20 PT - 91 tanks to be used for field trials and Armed Forces tests . The main battle tank ' s defense from high - explosion projectiles and missiles is increased by the new " Erawa " dynamic armor developed by the Poland Military - Technical Institute . This defense consists of 394 tiles with explosives , detonating in case of a direct hit . The tiles cover 9m on the tank . 108 tiles are placed on the turret , 118 on the hull and 84 on each side ' s anti - cumulative screens . The " Twardy " uses steel anti - cumulative screens instead of the rubber used on the T - 72 . Erawa ' s main difference from the Soviet analogs is that Erawa ' s containers fit almost without gaps while on the Soviet modernised T - 72 gaps reach 10 – 15 mm noticeably decreasing defense effectiveness . There are two Erawa modifications : " Erawa " - 1 and - 2 , differing in weight of the explosives . Experiments showed that the " Erawa " dynamic defense decreases the high - explosion stream proofing depth by 50 - 70 % and undercaliber projectiles by 30 - 40 % . Furthermore , explosive containers don ' t detonate when hit by bullets ( up to 30 mm ) , projectile or mine fragmentations , or when covered in burning napalm or petrol . The " Twardy " is armed with the same 125 mm smoothbore gun 2A46 used in the T - 72 , fitted with an automatic reloading mechanism which reduced the tank crew by one as it replaced the gun loader , and gave a rate of fire of 8 to 10 rounds " per " minute . Additional armament comprises the 7 . 62 mm PKT coaxial general purpose machine gun and 12 . 7 mm NSVT anti - aircraft heavy machine gun . The PT - 91 has a thermosmoke device generating smoke screens from fuel and 24 grenade launchers fitted with smoke or anti - personnel frag grenades . The modernization of the fire control system started by replacing the earlier used Soviet two plane stabilizer 2Є28M with a new stabilizer developed in Slovakia . It has an electronic information block showing the tank ' s technical condition . Furthermore it informs commander when effective sighted fire becomes ineffective because of an excessively high cross - country speed or other reasons . The Drawa fire control system , developed by Polish engineers , contains the gunner ' s day sight PCD and the TES thermovision night sight developed by the Israeli company ELOP , the commander ' s combined day - night passive observation and aiming sight POD - 72 , a ballistic computer , a laser rangefinder and a data system processing information for the ballistic computer . The sighting of the ballistic computer depends on the target ' s speed , weather conditions , projectile temperature and projectile type . The driver uses the control and diagnostic complex US - DK - 1 controlling the tank ' s main systems and displaying information on a monitor . The driver ' s night sight was replaced by the " Radomka " passive night sight . The modernized tank ' s increased weight led the developers to add a more powerful engine . It is a 12 cylinder S - 12U diesel engine , a modernized version of the Soviet V - 46 - 6 produced in Warsaw by PZL - Wola ( 850 hp instead of 780 ) . The main improvement is the modernized fuel and air injection system . This caused a noticeable decrease in the tank ' s road endurance . The latest " Twardy " variants have the 1000 hp S - 1000 engine with a turbocharger . Variants . PT - 91 " Twardy " . Production variant for Polish Army , extensively modernized development of T - 72M1 . Most of the vehicles are equipped with SKO - 1M Drawa - 1T dual - axis stabilized fire control system ( with TES - Thermal Elbow Sight - total number of delivered thermal sights is 202 < ref name = " NTW 05 / 09 " > Nowa Technika Wojskowa - May 2008 page 22 - Odmłodzona Drawa - by Andrzej Kliński < / ref > ) though some early production vehicles have a SKO - 1 Drawa ( with NV sight ) , " Erawa " reactive armour , a PCO SSC - 1 Obra - 1 laser - warning system and 850 hp PZL - Wola S - 12U engine . < ref name = " NTW 09 / 07 " > Nowa Technika Wojskowa - September 2007 page 14 - Jak można zmodernizować Twardego ? - by Andrzej Kliński < / ref > The first 20 initial production vehicles were delivered to Polish Land Forces in 1993 - 1994 with another 78 full scale production vehicles delivered 1995 - 1997 , 135 modernized T - 72M1 tanks ( made in late 80s ) delivered 1998 - 2002 . Both new and modernized tanks have the same combat capabilities . Depending exact configuration Polish Army uses PT - 91s in 3 variants PT - 91 , PT - 91M and PT - 91MA1 ( the M designation shouldn ' t be confused with the Malaysian variant ) . PT - 91A " Twardy " . Development variant with PZL - Wola S - 1000 1 , 000 - hp engine with mechanic transmission and number of other minor changes . Used for trials and as demonstrator on military exhibitions . PT - 91Z " Hardy " . ( " Z " for " Zmodernizowany " – literally " Modernized " ) Further development with SAGEM Savan - 15 fire control system , according to life fire test Savan - 15 has only minor advantage if accuracy over Drawa . < ref name = " NTW 11 / 99 " > Nowa Technika Wojskowa - November 1999 page 18 - Polskie T - 72 - Co dalej ? - by Tomasz Begier and Dariusz Użycki < / ref > The biggest advantage was a new gun stabilization system that gave a tank significant increase in accuracy when the tank is on the move . Later it was used as a base to develop PT - 91M . This variant has won a number of stress tests in Malaysia over T - 90 , T - 84 and K1 tanks , and has won the competition for a new Malaysian MBT . Only one prototype was made . PT - 91M " Pendekar " . ( " M " for " Malaysia " ) — production export variant for Malaysia with SAGEM Savan - 15 fire control system , PZL - Wola S - 1000R 1 , 000 - hp powerpack with Renk / SESM ESM - 350M automatic transmission bringing its top speed to 70 km / h , and a new communications system . Weapon s have been changed to a " Konštrukta defence a . s . " design 2A46MS 125 mm tank gun made by " ZTS - Špeciál a . s . " , a 7 . 62 mm FN MAG coaxial machine gun and a 12 . 7 mm FN Browning M2 HB AA machine gun . This variant is also equipped with Sagem VIGY 15 gyro - stabilised panoramic sight optronics , a SIGMA 30 laser gyro inertial navigation system , EADS EPS72 turret stabilisation system , a PCO SSP - 1 Obra - 3 laser - warning system , ERAWA 3 Explosive Reactive Armour , " ZM Dezamet 902A " 81mm grenade launcher s and Type 570P Diehl Remscheid GmbH tank track s . Two prototypes made ( renamed PT - 91E and PT - 91Ex ) , 48 serial PT - 91M vehicles produced 2007 - 2009 . < ref name = " NTW 10 / 05 " > Nowa Technika Wojskowa - October 2005 page 9 - Pierwsza prezentacja " Malaja " - by Andrzej Kliński < / ref > PT - 91E / Ex . ( " E " for " Export " ) - renamed prototypes of PT - 91M used as demonstrators of export variant showed on military exhibitions . PT - 91E is a first prototype named SP1 ( it is same vehicle as shown on military parade in Kuala Lumpur in 2005 ) , PT - 91Ex is a second prototype named SP2 . < ref name = " NTW 11 / 07 " > Nowa Technika Wojskowa - November 2007 page 15 - Pokaz " Malaja " i CV90120 - T na Drawsku - by Andrzej Kliński < / ref > Both vehicles faced number of tests in Malaysia SP1 was used for traction tests and has made 7000 km offroad in Malaysia , SP2 2000 km and 500 shoots from main cannon . Very similar to PT - 91M , offered for export to other countries . PT - 91P . ( " P " for " Peru " ) - Demonstrator for SITDEF Peru ' 2009 military exhibition . A cheaper alternative to PT - 91Ex . This variant is equipped with newest PCO Drawa - TG fire control system with a thermal sight and modern communication system ( Radmor RRC9310 radio , WB Electronics Fonet - IP communication system and Teldat battlefield management system ) . The vehicle was be shown on number of South American events including SITDEF Peru ' 2009 Expo . Peru decided to buy a Chinese MBT - 2000 ( a Type 90 development ) instead . < ref name = " NTW 04 / 09 " > Nowa Technika Wojskowa - April 2009 page 16 - Twardy na wystawie w Peru - by Andrzej Kliński < / ref > Related Vehicles . WZT - 3 . ( " WZT " for " Wóz Zabezpieczenia Technicznego " – literally " Technical Support Vehicle " ) – family of armoured recovery vehicle s based on the PT - 91 / T - 72 tank hull . Probably most popular T - 72 based ARV on the world with over 400 vehicles delivered to the clients . It is armed with a 12 . 7 mm ( ½ in ) machine - gun fitted to the commander ’ s hatch . Standard equipment includes : crane with telescopic jib that can lift a maximum load of fifteen tonnes , front - mounted stabilizing dozer blade , main and secondary winches . MID " Bizon " - S . ( " MID " for " Maszyna Inżynieryjno - Drogowa " – lit . " Engineering - Roading Machine " ; " Bizon " is Polish for " Bison " ) – Polish engineering tank based on the PT - 91 tank hull . PMC . ( " PMC " for " Pomocniczy Most Czołgowy " – lit . " Auxiliary Tank Bridge " ) – Polish Armoured Vehicle Launched Bridge is a close support bridge layer . The PMC - 90 , developed on the basis of PT - 91 , is able to carry out missions required to operations of combat forces . PZA " Loara " . ( " PZA " for " Przeciwlotniczy Zestaw Artyleryjski " – lit . " AA Artillery System " ; “ Loara ” means “ river ” in Polish ) – antiaircraft artillery system is a Polish armoured radar directed " Self Propelled Anti - Aircraft Gun " system developed in the late 1990s . Based around the " Twardy " chassis , this system mounts an armoured turret holding two Oerlikon KDA 35 mm cannons linked to a radar fire control system . It was planned that it would work closely together with PZR “ Loara ” ( anti - aircraft rocket system ) vehicles built on the basis of the PZA Loara but that project is currently on hold . The Loara is an autonomous fire unit capable of performing its tasks independently or acting as a component of a wider air defense system . The system has two radars , 3D search radar and engagement radar . The search radar has a range of 26 km ( 16 miles ) and is capable of tracking and identifying up to 64 targets at once . The radar system can also be operated on the move , refreshing its data every second . The system also has a laser range - finder , TV and FLIR cameras giving the system both all - weather day / night capabilities and the ability to operate entirely passively in a heavy ECM environment . The system also has a reaction time less than 10 seconds . The system can engage aircraft flying at altitudes from very low altitudes up to 5000 m ( 16 , 500 ft ) , and flying at speeds up to 500 m / s ( 1 , 125 mph ) . It is also effective against lightly armored ground and naval targets . PT - 94 " Goryl " . ( " Goryl " is Polish for " Gorilla " ) – project of a Polish main battle tank designed using experience gained on PT - 91 project . The tank would be similar in its design to Merkava ( engine at front ) . Armor : composite + ERA , main armament : 120 / 125 mm gun , 60 mm mortar , secondary armament : 7 . 62 mm PKT coaxial machine gun , 12 . 7 mm NSWT AA machine gun , crew : 3 . This program was also known under the name Anders . The program was cancelled at early stage . " Krab " . ( " Krab " is Polish for " Crab " ) - 155 mm NATO - compatible howitzer designed by HSW S . A . combining OBRUMs UPG chassis , licensed AS - 90M " Braveheart " turret with 52 - calibre gun and WB Electronics Artillery Fire Control System Topaz . The Howitzer is equipped with S - 12U engine and other elements ( like road wheels ) from PT - 91 . UPG / UPG - NG / PLC . ( " UPG " for " Uniwersalne Podwozie Gąsiennicowe " – lit . " Universal Tracked Chasis " ) - An OBRUM project to design universal base for family of tracked vehicles . UPG is not a vehicle but rather set of technologies used in particular vehicles . Many elements of UPG based vehicles are common with T - 72 / PT - 91 family of tanks . In 2009 OBRUM has begin studies on UPG - NG , the next generation of UPG uniwersal platforma . The most advanced vehicle of new family will be the PLC ( " Polski Lekki Czołg " - lit . " Polish Light Tank " ) . New vehicle will feature 120mm RUAG LWC main gun , MTU engine , active defence system , crew of tree and combat weight of between 30 and 40 tones . Project is in development stage , first prototype is planned to be showed on 2010 MSPO Kielce defence exhibitions . Serial vehicles are planned to enter service beyond year 2016 . Operators . Poland . 233 PT - 91 " s " were delivered between 1995 - 2002 ( 232 vehicles remain in service ) and 38 support vehicles based on the T - 72 / PT - 91 hull ( 29 WZT - 3M armoured recovery vehicle , 8 MID engineering tank and 1 prototype PZA Loara self - propelled anti - aircraft weapon ) . Units equipped with PT - 91 Twardy : Former units equipped with PT - 91 Twardy : At the introduction of PT - 91 the intention of Polish General Staff was to equip with PT - 91 all brigades of 11th Armored Cavalry Division , at the time the division had 4 brigades : 10th Armored Cavalry , 15th Armored Cavalry , 17th Mechanized and 34th Armored Cavalry . In 2002 10th Armored Cavalry received Leopard 2 A4 tanks donated to Poland by Germany , in 2007 the 15th Armored Cavalry was disbanded , same year 17th Mechanized received first KTO Rosomak , all this changes allowed the reallocation of PT - 91s to other divisions - replacing the oldest T - 72s . Typical Polish PT - 91 tank battalion equipped with 53 tanks is built of 4 frontline companies – 13 vehicles in each + 1 tank for battalion commander . Every company of 13 tanks is built of three platoons – 4 tanks in each + 1 tank for company commander . Malaysia . In March 2002 , Malaysia declared an intention to purchase 48 modernized PT - 91M and 15 support vehicles ( 6 WZT - 4 { WZT - 91M } armoured recovery vehicle , 3 MID - M { MID - 91M } engineering tank , 5 PMC Leguan { PMC - 91M } - armoured vehicle - launched bridge and one SJ - 09 driver training tank ) , ammo , spares and support for $ 370 million USD The tanks were delivered to Malaysia in 2007 - 2009 . Units equipped with PT - 91M : Rejimen - 11 KAD is the sole user of PT - 91M in Malaysian Army , PT - 91M has replaced FV101 Scorpion light tank . India . In April 1999 , India ordered 44 WZT - 3 armored recovery vehicles , which was followed by another two orders in April 2002 ( 80 vehicles ) , and in July 2005 ( 228 vehicles ) – for a total of 352 WZT - 3 armored recovery vehicles ordered . These vehicles are used to support the T - 72 and T - 90 MBT . Deliveries began in 2001 , and India is planning to upgrade its Ajeya Mk1 tanks ( local name for T - 72M1 ) to Ajeya Mk2 standard , with some elements from PT - 91 , such as the SKO - 1T DRAWA - T fire control system and the PZL - Wola S - 1000 engine . Kuwait . In the early 1990s , Kuwait ordered 170 M - 84AB tanks ( a T - 72M1 development ) , 15 M - 84ABK command tanks and 15 M - 84AI engineering tanks from Yugoslavia . The producer decided to purchase the license for the WZT - 3 instead of constructing their own design . The Kuwaiti M - 84AIs are almost identical to the original WZT - 3s . In 2005 , R . Bumar offered to modernize Kuwait ' s M - 84AB tanks with elements of the PT - 91 - competing with the Croatian proposed ( M - 84D ) . Both proposals , however , were refused .