Cardboard model of the Polish PT-91 Twardy tank

The model tank was made in 1:16 scale. The work was awarded at the 8th Competition of Paper and Plastic Models in Świdnik, Poland in 2014.

The PT-91 Twardy (Hard) tank is actually a modernized version of the Soviet T-72M1 tank. The tank was equipped with a more powerful engine. This did not increase the mobility of the machine, as its weight increased after the modernization. The new DRAWA fire control system was also introduced and the night observation devices were changed.

An interesting way was used to strengthen the tank's armor. Due to the high costs, the main armor was not modernized. Instead, a Polish patent was used. The basic armor was covered with the ERAWA reactive armor. Its pieces look like bricks. They are made of two steel plates with an explosive between them. This material is resistant to high temperatures, shrapnel hits and small arms fire. Only large-caliber shells hitting the outer plate exert a sufficiently high pressure to detonate the explosive contained in the armor brick. The inner armor plate is thicker. This causes the force of the explosion of the explosive contained in the brick to be directed outwards. This reduces the penetrating ability of the shaped-shells by about 70%, and for sub-caliber shells, i.e. those whose ability to penetrate results from high kinetic energy - 30%. Hit bricks reveal the base armor and it need to put new ones in this place.

In the years 1994-2002, 281 the PT-91 Twardy tanks were produced, 233 of which went to the Polish army, and the rest for export.

Some technical data:

• Length: 10.3 m (33 ft 9.51 in),
• Width: 3.72 m (12 ft 2.46 in),
• Height: 2.19 m (7 ft 2.22 in),
• Mass: 45.9 t (UK-45.2 t, USA-50.6 t),
• Speed on the road: 60 km/h (37.3 mph),
• Off-road speed: 35-45 km/h (21.7-28 mph),
• 850 hp supercharged 12-cylinder diesel V-engine (625 kW),
• Engine displacement: 38.88 l (2,372.6 in³),
• Off-road fuel consumption: około 480 l/100 km (UK-171 gal/100 mi, USA-205 gal/100 mi),
• Range with additional fuel tanks: 560 km (348 mi),
• Armor thickness:
  • Turret: 400 mm (15.7 in),
  • Hull: 220 mm (8.7 in),
  • Side: 80 mm (3.1 in),
• Crew: 3 (commander, gunner and driver-mechanic).

Armament:

• 125 mm (4.92 in) cannon (stock of ammunition: 39),
• Tank machine gun caliber 7.62 mm (0.3 in) (stock of ammunition: 2000),
• Anti-aircraft machine gun caliber 12.7 mm (½ in) (stock of ammunition: 300).

Overcoming obstacles:

• Depth of the ford: 1,20 m (3 ft 11.2 in),
• Height of the wall: 0,85 m (2 ft 9.46 in),
• Width of the ditch: 2,80 m (9 ft 4.20 in).

Sources:

• https://pl.wikipedia.org/wiki/PT-91
• http://www.smartage.pl/pt-91-twardy-polski-mbt/
• https://pl.wikipedia.org/wiki/ERAWA

20 Jun 2014