Design details
This T-80BV (a monument in St Petersburg) has reactive armour adapted to its turret and hull. The later T-80U has newer-generation reactive armour integrated into its design.
This T-80BV (a monument in St Petersburg) has reactive armour adapted to its turret and hull. The later T-80U has newer-generation reactive armour integrated into its design.

One of the T-80's advantages is the small size of the tank (about half to three quarters that of the U.S. M1 Abrams, depending on the aspect) and optimal internal volume (about half of the M1's, but a bit roomier for the crew than the T-72). This gives high armour to volume ratio (one of protection indices).

Except in more modern versions of the tank (like the T-84 Oplot), the ammunition is stored in the most protected area - below the crew inside the crew compartment in the autoloader carousel. This means that if the tank is penetrated, the ammunition can cook off, killing the crew and blowing the turret into the air. In most western tanks, like M1 Abrams, only part of ammunition is stored inside crew compartment and can cook off too; however, to protect the crew this ammunition is usually stored in a blast proof cabinet with blow out panels above it in case it ever does cook off. Autoloader speed is from 7.1 seconds to 19.5 s depending on the initial position of autoloader carousel.

The carousel itself is actually quite well protected. It is the rounds stored outside of the autoloader, especially those in the fighting compartment, that are mainly responsible for this "trademark" survivability issue, and this problem is made all the more acute by the use of semi-combustible charge casings instead of the traditional brass ones, giving almost no protection from the white-hot metal fragments sprayed inside the vehicle in the event of penetration. A T-80 restricted to carrying ammunition in its carousel greatly reduces this hazard, though it limits the vehicle to 28 rounds of ammunition (a fully laden T-80 can hold 45 rounds), which may be quite inadequate for most combat missions on the high intensity battlefield, but more acceptable in low intensity operations.

Due to the low turret roof, the lowest gun elevation is a few degrees below zero and so it is more difficult to find hull-down positions that the tank can fire from. The latest prototype, the T-84 Oplot, has an entirely new turret with armoured ammunition compartment. A disadvantage compared to tanks such as Abrams and Merkava is that T-80, being much lighter, has less thick armor, which the lastest Western rounds are expected to penetrate.

[edit] Models
T-80 graphic.
T-80 graphic.
T-80 in the field.
T-80 in the field.
T-80BV graphic.
T-80BV graphic.
T-80BV
T-80BV
T-80BV (this photo has been flipped left-to-right)
T-80BV (this photo has been flipped left-to-right)

* Ob'yekt 219 SP1 - Prototype. Essentially it was a T-64T with GTD-1000T multi-fuel gas turbine engine with the power of 1000 hp (746 kW).
* Ob'yekt 219 SP2 - Prototype. Ob'yekt 219 SP1 with bigger drive sprocket and return rollers. The number of wheels was increased from four to five. The construction of the turret was also altered while using the same apartment as the T-64A which was 125 mm 2A46 tank gun, auto loader and the placement of ammunition. Also some of the additional equipment came from T-64A. It was upgraded and in 1976 it became the T-80.
* T-80 (Ob'yekt 219) (1976) - First production model. The T-80 has some features of both the T-64 and T-72, and other features unique to itself. In general, the offensive capabilities of the T-80 are similar to the T-64A, but it is faster thanks to the GTD-1000T 1,000 hp (746 kW) multi-fuel gas turbine engine and better protected. Visual keys are large, die-cast, irregularly spaced, rubber-tired road wheels with three support rollers[2], a self-entrenching blade on the lower glacis, a large left-hand optic, and smoke grenade launchers on the rear of the turret sides (seven on the left side and five on the right side)[2]. Significant differences are a probable laser range finder, and probable enhanced armor on the glacis and turret (an upper glacis of steel layers enclosing fiberglass layers and a cast steel turret enclosing nonmetallic materials).[2] Ulike the later models T-80 had V-shaped splash plate on glacis plate. Only a few hundred were built between 1976 and 1978 before the production switched to the T-80B. Some T-80's were later upgraded to B level.[8][9][10][7]
o T-80M-1 - T-80 with an Arena countermeasures array fitted to rear of the turret's roof. It also has an armour belt around turret.[7]
o T-80B (Ob'yekt 219R) (1978) - This first major redesign features a modified turret with new composite K ceramic armor providing better protection against APFSDS kinetic energy penetrators. The protection level of the turret increased from 410 mm of steel to 500 mm of steel. It also includes 1A33 fire control system, 9K112-2 system which allows firing 9M112 "Kobra" (NATO code: AT-8 Songster) ATGM using the tank's barrel. The missile control box is mounted in front of the cupola and has angled support.[11] The ATGM may be launched while moving slowly and can be auto-loaded with the two halves mated during ramming but the stub charge is manually loaded. [2] Unlike T-80, T-80B doesn't have a splash plate on glacis plate.[6] [9][7]
+ T-80B obr.1980g. - T-80B with a new 1,100 hp (820 kW) GTD-1000TF gas turbine engine.
+ T-80BK (Ob'yekt 660) - T-80B command tank equipped with additional R-130 radio, TNA navigation set, a 2nd whip antenna and a telescopic mast. It doesn't have the 9K112-2 system. [9][12]
+ T-80BV (Ob'yekt 219RV) (1985) - T-80B with Kontakt-1 explosive reactive armour. The smoke grenade launchers were moved from either side of the main armament back to the either side of the turret and positioned between the turret side and the ERA panels. On the turret of the T-80BV, the panels are joined to form a shallow chevron shape. ERA is also fitted to the forward part of the turret roof to provide protection against attacks from above. While the ERA provides a high degree of protection against ATGM of it's time which relied on a HEAT warhead to penetrate armor over the frontal arc. It does not provide any added protection against APDS or APFSDS. Vehicles which were build first for sometime lacked the ERA because of supply problems. Some T-80BV tanks have been equipped with dust flap under glacis plate and some of them were equipped with single line of ERA along top of hull side. A late production version had a new turret similar to the T-80U but with Kontakt-1 ERA.[13][9][7]
# T-80BVK - As per T-80BK but with ERA. First models were just T-80BK tanks with ERA. Later models were T-80BV tanks with additional communications equipment and an antennae. [9][7]
+ T-80A (Ob'yekt 219A) (1982) - a further development of T-80B. It was developed in late 1970s and first model was produced in 1982. It was an attempt to provide the T-80B tank with an improved armour and firepower. It uses 1,200 hp (895 kW) GTD-1000M gas turbine engine.[6] It has the 9K119 system which allows it to fire 9M119M Refleks (AT-11B Sniper) ATGM using the tank's barrel.[6] It also had several pintle mounts for the NSVT heavy machine gun and other improvements. The ammo load for 125 mm smoothbore tank gun was increased considerably when comparing it to the one of T-80B (T-80B - 38 rounds, T-80A - 45 rounds). It has some features of the future T-80U including the new turret with stronger armour and equipped with a new fire control system with the 1G46 gunner's sight. However because of all those improvements T-80A is 2.8 tonnes heavier than the T-80B. It was further developed as T-80U. [14][7]
# T-80A obr.1984 - T-80A with Kontakt-1 explosive reactive armour. The model with Kontakt-1 is sometimes called T-80AV. The main difference between T-80BV and T-80A obr.1984 is the lack of missile guidance box in front of the commanders cupola.[7]
# T-80AK - Command variant of T-80A.[7]
* T-80AK obr.1984 - T-80A with Kontakt-1 explosive reactive armour. The model with Kontakt-1 is sometimes called T-80AKV.[7]
# T-80U (Ob'yekt 219AS) (1986) - (U for Ulushchenniy) A further development of T-80A. This version has a new 1,100 hp (820 kW) GTD-1000F multi-fuel gas turbine engine as well as 1A46 fire control system and a new turret. T-80U also received a different engine decking. 9K112-2 system was replaced with newer 9K120 system which allows firing 9M119 Svir (AT-11 Sniper) and 9M119M Refleks (AT-11B Sniper) ATGM.[2] Also the 12.7mm NSVT heavy machine gun received the ability to be fired from within the turret with a use of a remote-control which work in a similar manner to the one in T-64. Infra-red searchlight mounted on the commander's cupola is replaced with an image intensification channel. There's a laser designation system mounted on the tank's roof forward of the tank's commander cupola, it projects a modulated beam. The system is protected by a rectangular armored box cover. Like all of the previous T-80 models, the T-80U has full length rubber side skirts protecting the sides but those above the first three road wheels are armored and are provided with lifting handles. There are also rubber elements fitted beneath the front glacis which provide additional protection against mines with tilt-rod fuses and HEAT warheads. The forward skirt elements are armored and a radiation absorption liner coat is mounted on the inside and on the outside of armour. The turret roof between the commander's and gunner's hatches has been provided with additional protection against attack from above. Driver's protection, particularly against mine explosions, is enhanced by suspending the driver's seat from the hull roof. Two clusters of four 81mm 902B Tucha electrically operated smoke dischargers are mounted on either side of the turret. The new turret also has an improved frontal armor package with Kontakt-5 explosive reactive armour which defeats APFSDS. Early production version of T-80U still used Kontakt-1 ERA. A special camouflage paint distorts the tank's appearance in the visible and IR wavebands. GTA-18A Auxiliary Power Unit is used when the engine is off. Late production version had a more powerful GTD-1250D multi-fuel gas turbine engine and the "Brod-M" snorkel.[2][9][6][7]
* T-80U obr.1992 - T-80U with an improved 1,250 hp (930 kW) GTD-1250 multi-fuel gas turbine engine.[6]
* T-80U(M) - Improved fire control.
* T-80UK - Command version, equipped with additional R-163-50K and R-163-U radios, TNA-4 land navigation system, TShU-1-7 Shtora countermeasures system[9], electronic fuze-setting device that permits use of "Ainet" shrapnel round, a meteorological sensor, laser warning receivers, "Agava" thermal sight which provides a 2,600-meter night acquisition range, fire control and APU. Became the main Russian export tank in the 1990s. It can be easily recognized by EO boxes on the front of turret on either side of the main armament and multiple radio antennas.[2][7]
* T-80UE (1999) - Export version of the T-80U with some of the equipment from the T-80UK (including the TShU-1-7 Shtora electro-optical countermeasures system). Unlike the T-80U it doesn't have the anti-aircraft heavy machine gun mounted on the commander's cupola, instead it has pintle mounts at the four corners of the turret allowing it's position to be switched.[7]
* T-80UM - Russian version with a new weapon system for the 9M119M Refleks (AT-11B Sniper) ATGM, new thermal imaging sight "Agava-M1" (optionally "Agava-2" or "Buran-R") because of which the L-4 "Luna" IR has been removed.[7]
o T-80UM-1 "Bars" ‘Snow Leopard’ - Russian 1997 prototype with new Arena active protection system (Zaloga 2000:4).[7]
* T-80UM-2 - Russian prototype with KAZT Drozd-2 active protection system (Zaloga 2000:4).[7]
o Chorny Oryol (Ob'yekt 640) (Black Eagle) - A series of Russian demonstration prototypes with new turret including separate crew and ammunition compartments, blow-out panels on the ammunition compartment, new autoloader, Kaktus ERA, new targeting systems, and other undisclosed improvements. Six and seven-axle versions have been demonstrated. [14]
+ Desert Eagle - Tank based on the second prototype of the Chorny Oryol (Black Eagle) but it has a longer hull with 7 road-wheels. It is fitted with the KAZT Drozd-2 automatic protection system with it's launchers on either side of the turret. It's probably intended for export.[7]
* T-80UD "Beryoza"[15] (Ob'yekt 478B) (NATO code: SMT M1989) (1985[9]) - (Beryoza - birch-tree) Ukrainian diesel-engined version with 1,006 hp (750 kW) 6TD engine. Early production version used Kontakt-1 ERA which was later replaced with Kontakt-5 ERA.[9]
o T-80UDK - T-80UD command tank. Prototype only. [9]
o Ob'yekt 478BK - T-80UD with a welded turret.
o Ob'yekt 478BEh - T-80UD sold to Pakistan.[7]
o T-84 (Ob'yekt 478DU2) - Ukrainian development of the T-80UD, including T-84U, T-84 Oplot, and T-84 Yatagan models.