T-72 Design - Fire Power
The biggest difference between it and the previous models is that its fire power has been significantly increased. Its main weapon is the smooth- barrelled 125^mm diameter Cannon with which the tank can overcome all armored targets within the targeted fire field. The bullet's muzzle velocity reaches 1,500 m/s and the bullet has high armor-piercing ability. At the same time the probability of hitting the target and target distance also increase.
Bullet inventory consists of anti-personnel, under-gage armor piercing bullets and cumulative granades. The cumulative granades regardless of the distance of the target can also pierce armors corresponding to three to four times the thickness of their caliber.
The tank's personnel is 3 persons: driver, commander and gunner. The fourth member of the traditional tank crew, the charge handler is not needed because the charge is served up by an automatic charge-handling equipment. The bullets are of the divided type, the shot and the shell meet each other only in the cannon barrel. The shell's mantle burns up during the firing, only the sole-part made of metal remains.
The D-81TM 125mm gun uses three primary types of ammunition: APFSDS, HEAT, and High-Explosive/Fragmentation (HE-Frag). A flechette anti-personnel round is available but seems to be fairly rare. A variety of APFSDS rounds have been developed for the 125mm gun. Several types were in service in the 1970s, including the homogeneous steel 3BM9, the tungsten carbide-cored 3BM12 and improved types such as the 3BM15 and 3BM17.
The performance of the D-81 gun has been continually enhanced by ammunition improvements, with the Russians displaying depleted uranium BM-32 APFSDS rounds for the first time in 1992. Likewise, there were several HEAT projectiles which included the three-charge START-1 HEAT round—where the two outermost charges are precursor charges while the main charge resides in the middle of the round. The standard 30F19 high explosive/fragmentation round has an explosive fill of 3.15 kilogram.
The accuracy of the cannon's fire is increased by horizontal and vertical stabilizers. These keep the cannon constantly in the given target direction. The gunner as well as the commander can operate the targeting equipment which is also equipped with telemetry. Thus it has become possible for the commander to take over the firing and handle the targeting and fire activation. The tank can continue to do battle even in the event the gunner is disabled.
Like the earlier domestic-use-only T-64, the T-72 is equipped with an automatic loading system, eliminating the need for a dedicated crewmember, decreasing the size and weight of the tank. However, the autoloader is of a noticeably different design. Both the T-64 and T-72 carry their two-section 125 mm ammunition (shell and full propellant charge, or missile and reduced propellant charge) in separate loading trays positioned on top of each other; but firstly, in T-64, 28 of these were arranged vertically as a ring under the turret ring proper, and were rotated to put the correct tray into position under the hoist system in the turret rear. This had the disadvantage of cutting the turret off from the rest of the tank, most notably, the driver. Accessing the hull required partial removal of the trays.
The T-72 uses a design that has lower width requirements and does not isolate the turret compartment: the trays are arranged in a circle at the very bottom of the fighting compartment; the trade-off is the reduction of the number of trays to 22. The second difference is that in the T-64 the trays were hinged together and were flipped open as they were brought into position, allowing both the shell/missile and propellant charge to be rammed into the breech in one motion; in the T-72 the tray is brought to the breech as-is, with the shell in the lower slot and the charge in the upper one, and the mechanical rammer sequentially loads each of them, resulting in a longer reloading cycle.
To engage a target, the gunner begins by selecting the proper ammunition type on instructions from the tank commander. There are generally three ammunition options: sub-caliber (APFSDS), high-explosive- fragmentation (HE-Frag), and high explosive anti-tank (HEAT). Once selected, this puts the autoloader in motion. The autoloader cassette is fast, about 70 degrees per second in the horizontal axis, meaning that the ammunition is under the autoloader in less than three seconds.
While this is taking place, the gunner aims the cross-hairs of the main TPD-K1 at the target and fires the laser rangefinder with a finger control. The range is displayed in the sight and then has to be manually inputted into the tank's analog ballistic computer. Besides the range, the computer requires manual input of ballistic and meteorological corrections which are calculated from data available to the gunner before the engagement (barrel wear, charge temperature, barometric pressure and ambient temperature). The only automatic data input is for vehicle movement. The T-72M1 fire control system does not incorporate corrections for cross-wind data or inherent system errors.
The 2E28M gun stabilization system is two-axes: a vertical stabilizer in the main sight and a horizontal stabilizer for the hull, supplemented by an accelerometer. The 2E28M is based on mid-1960s technology and does not incorporate dynamic cant data. In addition, the high shock levels from firing require that the system be recalibrated after five or six firings. This limits the tank's ability to fire on the move.
This fire control system is similar in performance to that of the early 1970s generation of Western tanks such as the M-60A1 RISE, Leopard-1 A3, Chieftain Mk.5 or AMX-30. It is poorly suited to firing on the move because of the complexities of manual data input and inherent limits in the gun stabilization system. In the T-72, fire-on-the-move is accurate, even at short ranges, only when on level ground, at moderate speeds (up to 25 kilometers per hour) and against a target with small lead angles. Because of these limitations, all but the best crews will usually halt before firing.
While the gunner is aiming the main gun, the autoloader is preparing the ammunition for firing. This feature differs from most contemporary Western tanks (with the exception of the French AMX LeClerc) which have a third turret crewman to load the gun. After the gunner selects the type of ammunition desired at the beginning of the engagement, an ammunition cassette in the floor rotates and stops under the autoloader hoist at the turret rear when the proper type of ammunition is located. The gun is automatically elevated into the proper loading position. The autoloader hoist then brings up the two-piece ammunition from the cassette storage, rams the projectile into the breech, and next, the Zh40 propellant charge.
The gun then returns to the gunner's line of sight, and the weapon can be fired. The process will also eject the spent stub casing from the previous round out of the turret through a small port in the roof. The entire process from selecting the round until the gun is ready to fire takes 8 seconds. The system theoretically has a maximum rate of fire of 8 rounds per minute. In the event that something goes wrong in the process, a manual crank is mounted on the autoloader hoist. The gun has a theoretical rate of fire of only 2 rounds per minute when loaded manually.
The autoloader gives the T-72M1 a higher rate of fire on paper than earlier manually loaded guns such as on the T-62. But in practice, this has not proven to be particularly relevant in tank fighting. Manually loaded tanks such as the M-1A1 Abrams have a theoretical rate of fire of only 4 rounds per minute, but in practice, a well trained crew can get off three rounds in the first 15 seconds of an engagement.
Furthermore, the speed of target engagement is primarily dependent on the ability of the gunner to quickly acquire the target, perform the necessary calculations and aiming corrections, fire the gun and then switch to the next target. This is as much a function of training as technology. In both regards, NATO tanks long enjoyed a significant advantage. In NATO tanks such as the M-l Abrams and Leopard-2, the gunner's engagement sequence is automated to a greater extent than on the T-72M, with many data being automatically entered into the computer, and the computer taking a greater role in ballistic corrections.
The cannon's firing speed is 8 shots per minute. Its firing range is 9,400 meters. In order to decrease firing gas pollution in the manned area a smoke removing device is installed on the cannon's barrel. The thermal insulation cover on the cannon's barrel decreases deformation caused by heat and thus increases the shot's accuracy.
The tank's weaponry also includes the 7.62 millimeter machinegun which is parallel with the cannon and the 12.7 millimeter aerial defense machinegun.
External armament consists of a 12.7mm NSVT heavy machine gun, code named Utes (Rock). Unlike the T-64, the machine gun mounting on the T-72M1 is entirely manual, not remote controlled. The machine gun is aimed using a K-10 reflex sight mounted in a small protective container above and to the right of the gun. Two additional boxes of 12.7mm machine gun ammunition are stowed externally on the turret side.
In the front of the tank are 12 System 902B Tucha 81mm smoke dischargers. When fired together, this creates a smoke screen 300 by 300 meters lasting about two minutes. The T-72M1 also has the normal engine-mounted TDA smoke generating system. Crew protection is limited to a single AKS-74U or similar assault rifle, as well as grenades. Soviet tank crews are not regularly issued pistols. The T-72M1 is provided with the usual PAZ nuclear protection system. This system detects the radiation wave from a nuclear blast and automatically carries out actions to minimize crew injury from the subsequent shock wave. The interior of T-72Ml's crew compartment is protected with a layer of resin-impregnated lead antiradiation lining. This is found even on export tanks, for example, the Iraqi T-72Mls.
The T-72M1 is fitted with a passive image-intensification night vision system for the gunner, fitted in the TPD-K1 system. The commander often is issued with an image intensification night sight, typically the PNV-57 biocular face-mask type. He uses these outside the tank. In the event of inadequate light, it depends on an active infrared system for night combat, based around the L-2AGM infrared searchlight on the turret. The driver can use a similar system connected to the driving lights, and the commander is provided with his own small infrared searchlight which is independent of the main gun Luna searchlight.
This night fighting system is similar to those used by NATO in the 1970s. However, since the early 1980s, thermal imaging sights were introduced on tanks like the M-60A3, M-l and M-1A1 Abrams, Leopard-2, Challenger and AMX- 30B2. Thermal sights were only introduced on the latest models of the T-80 tank in the 1990s. The lack of modern night fighting sights was one of the main tactical drawbacks of Russian tanks compared with contemporary Western tanks.
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