T-90S

Armament
The T-90's main armament is the 2A46M 125 mm smoothbore gun. This is a highly modified version of the Sprut anti-tank gun, and is the same gun used as the main armament on the T-80-series tanks. It can be replaced without dismantling the inner turret and is capable of firing armour-piercing fin-stabilized discarding sabot (APFSDS), high-explosive anti-tank (HEAT-FS), and high explosive fragmentation (HE-FRAG) ammunition, as well as 9M119M Refleks anti-tank guided missiles. The Refleks missile has semi-automatic laser beam-riding guidance and a tandem hollow-charge HEAT warhead. It has an effective range of 100 m to 6 km, and takes 17.5 seconds to reach maximum range. Refleks can penetrate ~950 mm of steel armour and can also engage low-flying air targets such as helicopters.

The NSV 12.7mm (12.7x108) anti-aircraft machine gun can be operated from within the tank by the commander and has a range of 2 km and a cyclic rate of fire of 650-750 rounds per minute with 300 rounds available. The PKT 7.62 mm coaxial machine gun weighs about 10.5 kg while the ammunition box carries 250 rounds (7000 rounds carried) and weighs an additional 9.5 kg.

Like other modern Russian tanks the 2A46M in the T-90 is fed by an automatic loader which removes the need for a manual loader in the tank and reduces the crew to 3 (commander, gunner and driver). The autoloader can carry 22 ready-to-fire rounds in its carousel and can load a round in 4-5 seconds. It has been suggested that the automatic loaders on modern T-90 tanks have been modified to take advantage of newer ammunition such as the 3BM-44M APFSDS, which like the US M829A3 penetrates armour better than the previous shorter rounds. Additionally the T-90 features the Ainet fuse setting system which allows the tank to detonate HE-FRAG rounds at a specific distance from the tank as determined by the gunners laser range finder, improving performance against helicopters and infantry.

Fire control on the T-90 includes the PNK-4S/SR AGAT day and night sighting system mounted at the commanders station which allows for night time detection of a tank sized target at ranges between 700 and 1100 meters depending on the version of the sight. Early models of the T-90 were equipped with the TO1-KO1 BURAN sight but later models (T-90S) were upgraded to use the ESSA thermal imaging sight, which allows for accurate firing to a range of 5000-8000 m using the CATHERINE-FC thermal camera produced by Thales Optronique. The gunner is also provided with the 1G46 day sighting system which includes a laser range finder, missile guidance channel and allows tank-sized targets to be detected and engaged at a range from 5000 m to 8000 m. The driver users a TVN-5 day and night sight.


[edit] Protection

T-90S Bhishma of the Indian Army on displayThe T-90 is fitted with a "three-tiered" protection systems: First tier is the Russian version of Chobham armour in the turret; consisting of basic armour shell with an insert of alternating layers of aluminum and plastics and a controlled deformation section, composite armour. The Second tier is third generation Kontakt-5 ERA explosive reactive armor which significantly degrade the penetrating power of kinetic-energy APFSDS ammunition and also these ERA blocks give the turret its distinctive angled "clam shell" appearance. ERA bricks are also located on the turret roof and provide protection from top-attack weapons. The turrets forward armour package in addition to the ERA and steel plating contains a composite filler sandwiched of Russian version of Chobham armour between upper and lower steel plates, the composite armour takes advange lower weight and improve protection when compared with steel plate.

And the third tier is Shtora-1 (Russian: Штора-1 or "curtain" in English) countermeasures suite, produced by Elektromashina of Russia. This system includes two infrared jammers on the front of the turret, four laser warning receivers, two 3D6 aerosol grenade discharging systems and a computerized control system. The Shtora-1 warns the tank's crew when the tank has been 'painted' by a weapon-guidance laser and allows the crew to slew the turret to face the threat. The infrared jammer, the TShU1-7 EOCMDAS, jams the semiautomatic command to line of sight (SACLOS) guidance system of some anti-tank guided missiles. The aerosol grenades can be used to mask the tank from laser rangefinders and designators as well as the optics of other weapons systems. Indian T-90S tanks are not equipped with the Shtora-1 countermeasures suite.

Also in addition to the passive and active protection systems the T-90 is also fitted with nuclear, biological and chemical (NBC) protection equipment, KMT mine sweeps and an automatic fire fighting system.

During a reported test conducted by the Russian military in 1999 the T-90 was exposed to a variety of RPG, ATGM and APFSDS munitions. When equipped with Kontakt-5 ERA the T-90 could not be penetrated with any of the APFSDS or ATGM used during the trial and outperformed a T-80U which also took part.[23]