PT-91
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| PT-91 Twardy | |
|---|---|
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| Specifications | |
| Weight | 45.9 tonnes |
| Length | 6.67 m |
| Width | 3.4 m |
| Height | 2.19 m |
| Crew | 3 |
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| Armour | composite armour; front and side armor laminated; front, side and top armor behind Erawa-1/Erawa-2 ERA, steel side anti-cumulative screens |
| Primary armament |
1 x 125mm 2A46 (D-81TM) gun |
| Secondary armament |
1 x 7.62mm PKT coaxial machine gun, 1 x 12.7mm NSWT AA machine gun |
| Engine | PZL-Wola S-12U diesel 850 HP (630 kW) |
| Power/weight | 13.6 kW/t |
| Suspension | torsion-bar |
| Operational range |
650 km |
| Speed | 60 km/h |
The PT-91 Twardy (translated PT-91 Hardy, meaning resilient) is a Polish main battle tank. It is an extensive modernization of the T-72M1. It entered service in 1995. The PT-91 was designed at the Research and Development Centre of Mechanical Systems OBRUM and is produced by the Bumar Łabędy company. Changes from the T-72 include a new dual-axis stabilized fire-control system, reactive armour, a slightly more powerful 850-hp S12-U engine, and hydraulic transmission with seven forward gears and one reverse. In 1995 the PT-91 Twardy underwent a second modernization, called PT-91A, including a 1000-hp engine and a more advanced fire-control system, the automatic loader is also new.
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[edit] History
In the late 1980s the Polish Army modernized all of its obsolete T-55 tanks to the T-55AM Merida standard. The successful conversion convinced the General Staff that similar modernization could also be applied to other Soviet-made tanks in Polish service. In late 1988 it was decided to prepare a project of modernization for the T-72M1 design. The Gliwice-based Research and Development Centre of Mechanical Systems OBRUM (Polish: Ośrodek Badawczo-Rozwojowy Urządzeń Mechanicznych) 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-72S) 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 (meaning tough, or resilient in Polish). 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 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.
[edit] Development
| PT-91M Hardy | |
|---|---|
 |
|
| Specifications | |
| Weight | 46.5 tonnes |
| Length | 6.67 m |
| Width | 3.4 m |
| Height | 2.19 m |
| Crew | 3 |
|
|
|
| Armour | composite armour; front and side armor laminated; front, side and top armor behind Erawa-1/Erawa-2 ERA, steel side anti-cumulative screens |
| Primary armament |
1 x 125mm 2A46MS gun |
| Secondary armament |
1 x 7.62mm FN MAG coaxial machine gun, 1 x 12.7mm FN M2 HB AA machine gun |
| Engine | PZL-Wola S-1000 diesel 1000 HP (735 kW) |
| Power/weight | 16 kW/t |
| Suspension | torsion-bar |
| Operational range |
500 km |
| Speed | 70 km/h |
Starting from July 1991 T-72 modernization programs were implemented by the "Bumar" combinate which has been serially producing the T-72 under Soviet license. The modernized main battle tank got the indexation 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 polygon 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 9 m2 on the tank. 108 tiles are placed on the turret, 118 on the hull and 84 on each side's anti-cumulative screens. The PT-91 "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 effectivity. There are two Erawa modifications: Erawa-1 and Erawa-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 30mm), projectile or mine fragmentations, or when covered in burning napalm or petrol.
The PT-91 "Twardy" is armed with a 125-mm smoothbore gun 2A46 used in the T-72. The main gun is fitted with a reloading mechanism which allowed for removing the gun's loader as a crew member. With 8 to 10 rounds per minute the main gun has a great rate of fire. Additional armament comprises the 7.62-mm coaxial PKT and the 12.7-mm anti-aircraft NSVT machine guns. 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 2Je28M 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 not perspective in case of a too high cross-country speed or other reasons.
The fire control system Drawa 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 commander 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 passive night sight "Radomka".
The modernized main battle tank's increased weight led the developers to integrate a more powerful engine. It is a 12 cylinder S-12U diesel engine. The S-12U is a modernized version of the Soviet engine V-46-6 produced in Warsaw by "PZL-Wola" (850 h.p. instead of 780 h.p.). The main improvement is the modernized fuel and air feeding system. This caused a noticeable decrease in the tank's road endurance. The latest PT-91 "Twardy" versions have got the 1.000 h.p. S-1000 engine with an exhaust compressor.
[edit] Variants
[edit] PT-91
New production vehicle based on the T-72M1, extensively modernized with DRAWA dual-axis stabilized fire control, Erawa reactive armour, 850-hp S12-U engine. First 20 initial production vehicles were delivered to Polish Land Forces 1993-1994 with another 78 full scale production vehicles delivered 1995-1997.
[edit] T-72M1Z
T-72M1 upgraded to PT-91 standard, 135 T-72M1 tanks made in late 80s were overhaulled and modernised to full PT-91 standard, delivered 1998-2002.
[edit] PT-91Z
(Z for Zmodernizowany - modernized) — demonstrator of export variant showed on military exhibitions with SAGEM Savan-20 fire control system, 1,000-hp S-1000 engine. PT-91M was designed from PT-91Z. This variant has won a number of stress tests in Malaysia over T-90, T-84 and K1 tanks, and has won a whole commpetition for new Malaysian MBT. Only one prototype tank in this standard was made.
[edit] PT-91M
(M for Malaysia) — production export variant for Malaysia with SAGEM Savan-20 fire control system, 1,000-hp S-1000 engine bringing its top speed to 70 km/h, and a new communications system. Weapons have been changed to a 2A46MS 125mm gun, a 7.62mm FN MAG coaxial machine gun and a 12.7mm FN Browning M2 HB AA machine gun. 1 prototape made, 48 serial vehicles are in production now.
[edit] PT-91E
(E for Export) - demonstrator of export variant showed on MSPO 2006 military exhibitions, Poland. Similar to PT-91M, offered for export to other countries. Renamed prototype of PT-91M.
[edit] Vehicles based on PT-91
[edit] WZT-3
(WZT for Wóz Zabezpieczenia Technicznego) - Polish armoured recovery vehicle based on the PT-91 tank hull. It is armed with a 12.7mm machine-gun fitted to the commander’s hatch. Standard equipment includes: crane with telescopic jib that can lift a maximum load of fifteen tons, front-mounted stabilizing dozer blade, main and secondary winches. WZT-4 is a variant based on PT-91M and equipped according to Malaysian requests.
[edit] MID
(MID for Maszyna Inżynieryjno-Drogowa) - Polish engineering tank based on the PT-91 tank hull, designed for engineering units. MID-M is a variant based on PT-91M and equipped according to Malaysian requests.
[edit] PMC-90
(PMC for Pomocniczy Most Czołgowy) 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. PMC-Leguan is a variant for Malaysia based on PT-91M and equipped with the 26m long MLC 70 Leguan bridge system.
[edit] PZA "Loara"
(PZA for Przeciwlotniczy Zestaw Artyleryjski) antiaircraft artillery system is a Polish armoured radar directed Self Propelled Anti-Aircraft Gun system developed in the late 1990s . Based around the chassis of the PT-91 "Twardy" tank, system mounts an armoured turret holding two Oerlikon KDA 35 mm cannons linked to a radar based 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 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, and flying at speeds up to 500 m/s. It is also effective against lightly armored ground and naval targets.
[edit] PT-94 "Goryl"
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. (Armor: composite + ERA, Main armament: 120/125mm gun, 60mm mortar Secondary armament: 7.62mm PKT coaxial machine gun, 12.7mm NSWT AA machine gun, Crew: 3). This program was also know under the name Anders. The program was cancelled due to lack of funds.
[edit] Operators
Poland. 233 PT-91 delivered between 1995-2002 (older tanks received a number of upgrades to match the new ones) and 39 support vehicles based on the T-72/PT-91 hull (29 WZT-3 armoured recovery vehicle, 8 MID engineering tank and 2 PZA Loara self-propelled anti-aircraft weapon).
Malaysia. In March 2002, Malaysia declared an intention to purchase 48 modernized PT-91M Twardy's and 14 support vehicles (6 WZT-4 armoured recovery vehicle, 3 MID-M engineering tank and 5 PMC Leguan - armoured vehicle-launched bridge) for $275 million USD. Delivery began in 2005.
India. In April 1999, India has ordered 44 WZT-3 armored recovery vehicles, this order was followed by another two orders in April 2002 (another 80 vehicles) and in July 2005 (228 vehicles) – that gives the total number of 352 WZT-3 armored recovery vehicles ordered by India. Vehicles are used to support units with T-72 and T-90 MBT. Deliveries began in 2001. Also 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 SKO-1T DRAWA-T fire control system and PZL-Wola V46-6 engine.
[edit] External links
- BUMAR Group Web Site — Polish Military Consortium - manufacture of PT-91 - (PT-91 Summary)
- PT-91 Twardy Main Battle Tank at globalsecurity.org
- PT-91 at army-guide.com
- Polish Armour Thread at militaryphotos.net
- PT-91 Galery
 Ariete | Arjun |  Challenger 2 |  Ch'onma-ho |  K1 | K2 Black Panther |  Leclerc |  Leopard 2 |  M1 Abrams |  / MBT 2000 M-84 |  Merkava | PT-91 Twardy |  T-80 |  T-84 |  T-90 |  Type 90 | Type 96 | Type 99 | Zulfigar |
