T-80

With contributions by Mike Ennamorato, including this introduction.

Although the T-80 is mostly remembered in the Western world for its lackluster performance during the invasion of Grozny, there was once a time when it was one of the most highly regarded assets in the vast Soviet tank fleet. In terms of technological novelty and sophistication, the T-80 was the top of the line and primarily distinguished itself from the T-64 and T-72 by having a gas turbine engine. Thus, by the end of the 1970's, the Soviet Army was the only army in the world to simultaneously operate three different main battle tanks with three different engines: an opposed piston diesel multifuel engine, a traditional V-shaped diesel multifuel engine, and a gas turbine multifuel engine.

As one should come to expect from anything on the other side of the Iron Curtain, the inception of the T-80 is rather intriguing story. While the Kharkov engineers were still ironing out issues with the 5TDF opposed-piston engine for the T-64, experiments on mounting a turboshaft engine were already in full swing. It was requested that production expand from just Kharkov (KMDB) to Kirov (LKZ) and Nizhny Tagil (UKBTM) as well. Both of the latter plants struggled to produce some of the more complex parts for the T-64 - namely the engine - due to a lack of personnel familiar with the intricacies of the fundamentally different engine, and hence, created their own variations of the basic T-64. UKBTM and LKZ split design elements and ended off designing what came to be known as the T-72 and T-80 respectively. LKZ's progeny were defined by their signature turbine engines and more robust suspension as well as a revised hull in order to accommodate the larger engine compartment and new suspension. The new hull was hybridized with the turret of the T-64A, thus forming the original model T-80. The early Object 219 sp.1 prototypes (of which few were produced) bore an even closer resemblance to the T-64A, as it was practically the same tank with the exception of the enlarged engine compartment and the different engine.

Upon entering service after extensive testing alongside its cousins the T-64A and T-72 in various climates, it was clear that this new vehicle was far more extravagant and expensive than the ones preceding it, making the T-80 much less common than its counterparts. It also came off as being a more ambitious project than T-72 (evidenced by a far longer development span). However, the final production model T-80 (Object 219 sp.2) came too late for its own good. The instant it entered low-rate production in 1976, it was already surpassed in capability by both the T-64B and T-72A: a troubling situation for a vehicle meant to replace and supplement them, made worse by its excessive price tag. As a result, the T-80B was quickly ushered into service a mere two years after the T-80, boasting the ability to fire ATGMs from the cannon while on the move with the Kobra system, and an updated armour layout that had better prospects against the latest and future anti-tank munitions. Beginning in 1980, a more powerful 1100 hp GTD-1000TF engine was installed in all new-production tanks. These upgrades along with the addition of Kontakt-1 explosive reactive armour and a further enhanced composite armour package formed the basis of the T-80BV, which arrived in 1985. The most advanced direct T-80 variant - the T-80U, arrived in 1986, and came with the revolutionary but flawed Kontakt-5 heavy reactive armour package. This new model presented improvements to just about everything; a new digital fire control system, engine, explosive reactive armour, and some other tidbits. Some late model T-80BV tanks had the T-80U turret installed but retained the familiar coat of Kontakt-1.

So without any further ado, let us dive deep into the intricacies of the T-80.

Table of Contents

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1. Commander's Station
2. Gunner's Station
3. T-80 Fire Control System
4. T-80B Fire Control System
5. T-80U Fire Control System

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6. Stabilizers
7. 2E28M2 "Sireneviy"
8. 2E42M1
9. Autoloader
10. Loose Stowage
11. Cannon
12. Missiles
13. PKT Co-axial Machine Gun
14. NSVT Anti-Aircraft Machine Gun

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15. Protection
16. T-80
17. T-80B
18. T-80BV
19. Kontakt-1
20. Kontakt-5
21. Smoke Screen
22. Firefighting
23. NBC Protection

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24. Driver's Station
25. Transmission, Suspension
26. Engines
27. Water Obstacles
28. Road Endurance

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As of 23 February 2019, this article is still undergoing minor renovations. If there are any errors or inconsistencies, feel free to write them down in the comments section

The section on the armour protection of the T-80 and its variants - specifically the T-80U - can only be considered a rough guideline as of February 2019. It is still being renovated pending further research.

COMMANDER'S STATION

The commander is seated on the right hand side of the turret and enters through a relatively tight clamshell-shaped hatch. The hatch is sprung with a torsion spring to make it easier for the commander to open the heavy armoured hatch, and the hatch offers protection from bullets when locked in the open position. If the commander wants to fight outside the hatch or simply take in the his surroundings with his head out and a pair of binoculars, he is almost fully shielded from sniper fire from the front, and the hatch can be spun around along with the cupola to face any direction.

Just like with the T-64 before it, accommodations for the commander are relatively spartan but still objectively superior to the T-54 and T-62 medium tanks. The commander's seat is well padded and adjustable in height and legroom is not in short supply, but there are not many concessions for width below waist level. This is due to the layout of the MZ autoloader which stowed ammunition in a ring around the turret ring. This reduced the internal diameter of the crew compartment in the hull which was already not particularly wide. However, this is not necessarily a problem as the amount of room for the commander's upper body is more than adequate.

In summertime, the roominess of the commander's station is acceptable for the average Soviet tanker, but in winter, the commander's bulky clothing cuts down on the already modest volume of habitable space. Taller people will not find it perfectly habitable as there is plenty of headroom. For ventilation, there is a small DV-3 plastic fan mounted on a ball joint just in front of him. It is enough for European summers considering the international standards for tank ventilation of the time (there were none), but not the high heat of Northern Africa and the Middle East. Because the commander is seated inside the turret cabin, he is isolated from the hull where the NBC filtration and ventilation system is installed. As such, there is virtually no airflow inside the turret cabin besides the breeze from the DV-3 plastic fan.

Like with the T-72 and T-64, the commander of the T-80 is supplied with four general vision periscopes, but the designers managed to remedy the rearwards blind spot with the inclusion of a TPNT-1 rear view prism block embedded into the center of the hatch. It is useful for directing the driver while buttoned up. In non-combat situations, the commander could just open his hatch and peek out, of course. The TKN-3 observation device directly in front of the commander is supplemented by two TNPO-160 periscopes embedded in the fixed cupola roof pointing in the 10 o'clock and 2 o'clock sectors and another two TNPO-165 periscopes embedded into the hatch pointing in the 8 o'clock and 4 o'clock sectors, thus giving him a generous field of view around the turret. With the inclusion of the TNPT-1 rear view prism, the commander theoretically has a full 360-degree view around the turret from six observation devices. While not as comprehensive as many NATO tanks in terms of the number of observation devices, the cupola of the T-80 is rotatable, so the dead zones between the periscopes are easily eliminated by simply rotating the cupola. In broader terms, general vision periscopes are useful for directing the driver, checking the positions of the commander's platoon mates and getting a sense of the surrounding environment.

However, the commander's responsibilities are not limited to simply monitoring the situation outside. In case the autoloader malfunctions, the commander is also responsible for manually operating the autoloader carousel. The ammunition type indexer memory unit (YELLOW) performs the double function of an indicator unit with LEDs in it to show what type of ammunition is currently aligned with the elevator and ramming mechanism so that the commander knows when he has reached the desired ammo type -

- and the silver-gray object (RED) underneath it is the hydroelectric carousel rotation drive motor. If all electrical power is cut to the tank, rotating the carousel is achieved by working the hand crank attached to the side of the motor.

The commander also has a control dial to operate the autoloader in the semi-automatic loading mode where he can control the loading process step by step to use the remaining functional parts of the system in the event of an autoloader failure or troubleshoot issues with the autoloader. From this dial, the commander can hydrolock the cannon in the loading position, raise the ammunition cassette to the loading position, ram the ammunition into the cannon breech, return the ammunition cassette to the carousel, and return the cannon to the stabilized mode whereby it is ready to fire. The commander is provided with an ammunition type selection dial (BLUE) to allow him to select the type of ammunition that is to be loaded when operating the autoloader in the semi-automatic mode.

Besides all that, the commander is provided a control box (GREEN) to control the autoloader replenishing procedure. The autoloader replenishing procedure can be described as the normal loading procedure except run in reverse, and without the ramming step.

Besides having his general vision periscopes and controls, the commander also gets to play around with a multifunctional pseudo-binocular TKN-3M sight. This is his primary means of observation.

TKN-3M "Kristal"

The original T-80 from 1976 was equipped with the TKN-3M pseudo-binocular combined periscope, similar to the T-64 and T-72 before it. Pseudo-binocular meaning that although the device has two eyepieces, the two optic feeds are combined to one aperture, which the viewer sees out of. It has a fixed 5x magnification in the day channel with an angular field of view of 10°, and a fixed 3x magnification in the night channel with an angular field of view of 8°. The periscope can be manipulated up and down for elevation, and the commander's cupola must be manually spun for horizontal viewing.

By 1976, the TKN-3M was already somewhat obsolete. It featured target cuing and was very compact, but it wasn't stabilized, and featured only rudimentary rangefinding capabilities and its night vision capabilities were only borderline acceptable for 1976. Night vision came in two flavours; passive light intensification or active infrared. In the passive mode of operation, the TKN-3M intensifies ambient light to produce a more legible image. This mode is useful down to ambient lighting conditions of at least 0.005 lux, which would be equivalent to an overcast, moonless and starless night. In these conditions, the TKN-3M can be used to identify a tank-type target at a nominal maximum distance of 400 m due to the resolution limit, but as the amount of ambient light increases such as on starlit or moonlit nights, the distance at which a tank-sized target is discernible can be extended. In dark twilight hours, the TKN-3M may be able to make out the silhouette of a tank at a distance of up to 800 m or more, but the sight is hamstrung again, this time not by the absence of light, but by the low magnification. Any brighter than dawn or dusk, and the image will be oversaturated and unintelligible.

The active mode requires the use of the OU-3GA2 or OU-3GKU IR spotlight, which connects directly to the tank's 27V electrical system. With active infrared imaging, the commander can identify tank-type targets from a distance of around 400 m, or potentially more if the opposing side is also using IR spotlights. In that case, the TKN-3M can be set to the active mode but without turning on the IR spotlight. The switch for activating the spotlight is the right thumb button while the operating channel selector is on the TKN-3M itself. The problem with spotlights as a whole is that while the user can use them to spot for targets, the targets can use them to spot the user too, but from much further away. However, the OU-3 design is particularly flawed in this respect because it lacks an occluder. The lack of an occluder means that around half of the light from the spotlight is projected directly forward instead of into the parabolic reflector. As such, an enemy observer will not only see a circular patch of light. When observing a Soviet tank with its IR spotlight on, a large portion of the tank will be brightly illuminated. The additional illumination brings the minor benefit of lighting up the ground for the driver to see more clearly, so the common issue of speed control due to short visibility distance with the complementary IR periscope for the driver is slightly alleviated in battle conditions.

The maximum distance at which a tank-sized target can be identified in the active mode is stated to be 400 to 450 meters, although the spotlight can illuminate objects further away than that. The main issue is the low resolution of the image and the low magnification factor of the TKN-3M. The OU-3GA2 and OU-3GKU spotlights are not particularly powerful. Both use an incandescent lamp that consumes just 110 watts and the spotlights have an aperture diameter of only 215 mm. The only difference between the two spotlights is the shape of the hinges on which the spotlight lamp is mounted.

Without the infrared filter, the spotlight emits white light at 240 candelas. The infrared filter prevents all but approximately 0.001% of the light in the visible spectrum (360-760 nm) to pass through, and the light that passes through is at the higher end of the visible spectrum. As such, the spotlight emits a very faint red light with an intensity of around 0.24 candelas that can be perceived by the naked eye at close range when the OU-3 spotlight is activated in low light conditions. The intensity of near infrared light is much higher, of course. This light can be detected by the photosensor of a digital camera without an infrared blocking filter. The photosensor displays this infrared light - which is otherwise invisible - as pink light. This can be seen in the photos below, showing the OU-3 of a BRDM-2 (pictures from kmshik from the Gaz 69 forum).

When the OU-3 spotlight is used without the infrared filter, the TKN-3M can be used at night in the daylight mode possible and the viewing distance can be increased at the cost of exposing the exact location of the tank to everyone. This is permissible in certain circumstances, but it is not common.

Overall, the TKN-3M offers very poor night viewing capabilities compared to modern thermal imaging sights, but it was an improvement over the original TKN-3 model from 1964 due to the inclusion of image intensification technology, which was appropriately advanced for the time. However, by the late 1970's, the system was outstripped by more advanced Western passive image intensifying optics.

The OU-3GA2 spotlight is mounted coaxially to the TKN-3M periscope via a connecting rod, visible in the photo below to the left hand side of the spotlight. Due to the vertical offset in the mounting position of the spotlight, some parallax error is to be expected.

Rangefinding is accomplished through the use of a stadiametric scale sighted for a target with a height of 2.7 m, which is the average size of the average NATO tank. The TKN-3 is not stabilized, making it difficult to reliably identify enemy tanks or other vehicles at extended distances while the tank is travelling over rough terrain, let alone determine the range. The left thumb button initiated turret traverse for target cuing. The range of elevation of the periscope is +10° to -5°. Because the OU-3GA2 spotlight is directly mechanically linked to the periscope, the elevation angles remain the same when using the TKN-3M in the night vision mode.


Target designation is done by placing the crosshair reticle in the periscope's viewfinder over the intended target and pressing the cue button. The system relies on the use of a single direction sensor installed on the cupola ring, so the system can only account for the cupola's orientation and not the elevation of the TKN-3M, so the cannon will not elevate to meet the target. This was not a serious issue because the gunner should be able to see the target quite easily from his sight once the turret has slewed on target.

TKN-3 viewfinder

PNK-4S Universal Sighting Complex

For the Soviet optronics industry at the time, the PNK-4S was only a small technical innovation, but the device placed the T-80 on the same level as the best NATO tank at the time, namely the Leopard 2 with its revolutionary PERI-R17 independent panoramic sight. Like the PERI, the PNK-4S complex combines the functionality of an auxiliary gunnery complex with that of a comprehensive surveillance unit, giving the commander full authority with regards to the fire control system including the ability to directly override the gunner, which can be useful in some situations, such as to immediately engage a standout threat at the very instant it is spotted. All this is done with a simple thumbstick on the control module located to the right of the TKN-4S pseudo-binocular surveillance device around which the PNK-4S system revolves.

The decision to use a thumbstick was probably because a full joystick could not be easily manipulated with precision while the operator's body and arm was rocking around if the tank were going over rough terrain, while the thumb would be completely stationary if the hand was securely gripping the handgrip. The index finger rests on the trigger button at the back of the handgrip.

The PNK-4 system is a part of the 1A45 fire control system, as it connects directly to the tank's ballistic computer and fully duplicates the control scheme of the gunner. It can also be used independently from the fire control system in case of an emergency as explained further in the TKN-4S section. When used in the gunnery mode, the PNK-4 module is locked facing forwards. Horizontal cupola rotation control then becomes horizontal turret control, and vertical sight movement then becomes gun elevation. Independent vertical stabilization is still present, so that the sight does not elevate when the gun does to load.

The control module has all the necessary controls for the use of the main gun, including ammunition selection vis-à-vis the autoloader. Late T-80U variants with a remotely controlled anti-aircraft on the cupola would also make use of this control module for aiming and firing. With all this and the TKN-4S sighting complex, the T-80U could boast of having one of the most sophisticated hunter-killer systems in the world at the time.

TKN-4S

The foremost improvement of the TKN-4S over the TKN-3M is the addition of an independent stabilizer with its own gyroscopic sensor and compensator motor, visible on the left side of the main periscope housing as the large bulging module. The stabilizer is designated as the 1ETs29-4s. The stabilization accuracy on the vertical plane is at least 0.30 mils, while the stabilization accuracy on the horizontal plane is much lower at 0.88 mils, because of the much greater burden of the cupola compared to the mirror in the sight aperture. This means that the maximum deviation from the original point of aim is 0.30 m vertically and 0.88 m horizontally at a distance of 1000 m. The sight can maintain this level of performance while the cupola is rotating at speeds of up to 35 degrees per second. The vertical range of elevation is quite reasonable, spanning from -10° to +20°, granting the commander an uninterrupted line of sight on any given target while the tank is on the move over terrain of any degree of impassibility (within reason).

Another major improvement over the TKN-3M came in the form of a higher maximum magnification factor of 7.6x in the day channel in the high magnification setting, along with the option to switch to a low magnification setting of 1.0x. The night channel has a fixed 5.2x magnification. The principal advantage of the increased magnification in daytime is that it enables the commander to see and designate targets at ranges suitable only for missiles and beyond what was determined to be the maximum effectiveness threshold for ballistic munitions. The field of view under x1 magnification is 47° for the day channel and 7° under maximum magnification, or 7°40' under maximum magnification in the night channel, owing to the relatively low effective viewing distance at night. The night vision module uses newer third generation light intensification technology; better than what the old TKN-3MK had, but still not competitive against first-gen thermal imagers. Like the TKN-3, the TKN-4S can operate under active IR imaging or passive light intensification. In the latter case, the TKN-4S facilitates the identification of a tank-type target at a distance of at least 700 meters under ambient lighting conditions no brighter than 0.003 lux. This is a major improvement over the TKN-3MK, which only allowed the user to identify a tank type target at 400 meters under 0.005 lux of ambient light. The viewing distance for the TKN-4S can be improved by the presence of moonlight, which can increase the viewing distance by several hundred meters.

Because the TKN-4S is designed to use the same OU-3GA2 spotlight as the TKN-3, the active mode option does not present any improvements, only just enabling the commander to identify a tank-type target at a distance of 800 m. This is a significant improvement, but still vastly inferior in general effectiveness compare to 1st Gen thermal imaging systems.

The difference between the active and passive modes of operation is that in the active mode, the maximum practical viewing distance changes minimally across a wide range of ambient lighting conditions and weather conditions. Passive light intensification is more sensitive in this respect. If not for mortar and artillery-delivered IR illumination flares which could be aimed and shot over enemy positions, active infrared imaging would be completely obsolete. In such a scenario, however, the IR spotlight is rendered totally redundant.


In hindsight, it is quite clear that pursuing light intensification technology instead of investing in prospective thermal imaging technology was a huge mistake, one that ended up setting back the Soviet Union by nearly a decade in this particular field. Up until quite recently, modern day Russia had still been playing catch-up with Western tanks by assimilating French sighting technology through technological cooperation. However, that doesn't change the fact that the TKN-4S still had a fairly modern nightvision feature, when the day-only PERI-R17 didn't. All in all, the TKN-4S was arguably one of the most advanced and most versatile device of its type available to any modern tank in the world, until that title was usurped after the fall of the USSR when the new CITV was introduced on the M1A2 Abrams in 1992 along with the new PERI-R17A2 in 1998. Both had thermal imaging technology, and were generally better in every possible way.


Unlike the TKN-3, which had only a simple lead measuring scale and a stadia rangefinder scale, the TKN-4S has markings for all ammunition types and all the necessary range and lead scales, plus the stadiametric rangefinder. Because the PNK-4 system lacks a ballistic computer and laser rangefinder, the targeting procedure is devolved into manual mode. The commander must manually find the range to the target using the stadia scale, of which there are two. The one on top is for a target 2.5 meters in height, for a modern tank-type target like the Leopard 2 and Abrams, which are shorter than their predecessors. The one below it is for a target 2.0 meters in height, for APC-type targets like the M113.

Besides all that, the TKN-4S has a handy 1x periscope installed just under the rubber forehead pad for wider forward vision, supplementing the two TNPO-160 periscopes flanking the device. It's not much, but it does grant the commander an almost totally uninterrupted field of vision around the frontal 180-degree arc of the cupola.

The PNK-4S system uses a different cupola counterrotation motor from the one used for the TKN-3. Instead of a motor mounted at the turret ring that was joined to the cupola by a cardan shaft, the cupola rotation motor for the new cupola was installed on the turret roof and connected to the cupola via a drive sprocket. The motor is powerful enough to spin the cupola at a maximum speed of 40 degrees per second, easily outstripping the turret, so there is no danger of the commander losing visual contact of his target. The electronic components for the control of the cupola rotation motor are contained inside an armoured box mounted externally above the housing for the TKN-4S sight, as shown in the photo above.

Strangely enough, the PKN-4 complex does not include a laser rangefinder, despite the availability of quite compact models already in the late 70's. To determine the distance to a tank-type target, the commander must still rely on a stadiametric ranging scale similar to the type found on the TKN-3, although the precision of the operation may have increased marginally thanks to the higher magnification factor. Still, this isn't that big of a problem, because the gunner can quickly and painlessly conduct ranging himself anyway, and the gunner should be putting more time in observing the target than the commander anyway, who is supposed to be spending his time looking for other things to shoot at.

GUNNER'S STATION

The original T-80 turret was essentially identical in form and in function to the one from the T-64A, the T-80 itself being a derivative of it. Just like the turret of the T-64A, the gunner in the T-80 was provided with nothing but a single front-facing periscope for general vision. Later on, both the T-80B and T-80U turrets gave the gunner's station two TNPO-165 general vision periscopes facing forward and one TNPO-160 periscope aimed to the left, giving the gunner a good view of his surroundings in addition to helping to improve the lighting condition of his station, which is pretty neat as well.

Keep in mind that in most NATO tanks, the gunner is not provided with any general vision devices at all, but inversely, the station in the T-80 is slightly more cramped and amenities are few are far in between. Wider tankers will find it very difficult fitting into the station due to the narrow hatch, but lankier people will find the tank more accommodating, especially since there is plenty of room to stretch his legs. If the gunner is short and slim, all the better.

Besides the controls for gunnery related things, the gunner also has access to a multitude of toggle switches for a variety of things around his station. Among them are switches for the ventilation system (just below his hatch), switches for the dome light, switches for the intercom system, and others.

The new and more spacious turret of the T-80U also enabled the crew to carry a small number of additional cartridges. It certainly was not the most reassuring design feature, but more importantly, the ammunition somewhat reduced the available space, so removing them was quite normal.

Fire Control

Being the best tank in the Soviet Union meant a few things. One of them was having the best optics and compact computer technology money could buy. One of the few interesting and unique traits of Soviet-style sighting complexes was the control handles. Instead of a thumbstick like on the Chieftain or a pair "steering wheel" style hand grips where turret slewing was done by turning the handles like, well, a steering wheel (z-axis), spinning the turret was done by rotating the grips on the y-axis. The hand grips have two buttons each. The left trigger button is for firing the coaxial machine gun and the left thumb button is resetting the laser rangefinder. The right trigger button is for firing the main cannon, and the right thumb button is for firing off the laser rangefinder.

T-80 obr. 1976

TPD-2-49

The earliest T-80s were essentially modified T-64As, and as such, they had a great many things in common. Among these commonalities was the use of the TPD-2-49 optical coincidence rangefinder.

By 1976 standards, the TPD-2-49 was already incredibly outdated. It was first used on the original T-64 introduced in 1966, but since then, the TPD-K1 laser rangefinding sight had been invented and was already in use on the T-64B and T-72A, both introduced in 1976.

The optic aperture is split into two halves, top and bottom. The two input lenses see different parts of the same target, and the gunner must use the adjustment dial near his hand grips to line up both halves and obtain a seamless picture.

This process was cumbersome and somewhat inaccurate - the error margin was 3 to 5%, which meant that the range could be off by up to a shocking ±200m at 4000m, or a much less serious ±30m at 1000m range. However, it's worth considering that the average tank engagement distance expected in Europe was estimated to be 1500m, relieving the TPD-2-49 somewhat. Plus, the use of hypersonic APFSDS ammunition meant that the error margin could usually be ignored since the ballistic trajectory was so flat that amount of drop was completely negligible at out to 1500m or more. The problem was much more pronounced with HEAT and HE-Frag ammunition, which were heavier, had a worse ballistic coefficient and traveled at much lower velocities. With the advent of long range ATGM systems mounted on jeeps, scout cars, IFVs and even light tanks, accurate long-distance fire with HEAT and HE-Frag shells was imperative.


One downside of optical coincidence rangefinders is that they tend to have reduced accuracy on camouflaged targets. Tanks or other targets concealed with camouflage netting and bushes can be difficult to accurately range because the outlines of the tank may not be very clear to the gunner, and determining the silhouette through other visual cues is time consuming, not to mention that it requires at least a fairly experienced gunner. Other methods of breaking up the silhouette of the tank can be effective. As such, the T-64A turret and fire control system could be considered practically obsolete by the time it was integrated as part of the T-80, so only a few hundred of the original 1976 production variant were ever manufactured and some were subsequently brought back up to current technological standards with the retrofitting of the TPD-K1 sight during the early 1980's.

TPN-1-49-23

The TPN-1-49-23 was the gunner's night vision sight for the original T-80, but it was relatively short-lived and it was replaced soon after by the more advanced TPN-3-49. The TPN-1-49-23 can either use ambient light intensification or use infrared light conversion and intensification by relying on the L-4A "Luna-2" IR spotlight for illumination. The Luna-2 spotlight is mounted coaxially to the main gun. Unlike the commander's OU-3GA2 or OU-3GKU spotlight, the L-4A spotlight uses a xenon arc lamp with an IR filter instead of an incandescent lamp. It draws power from the tank's 27V electrical system and consumes 600 W of power. Removing the IR filter transforms the IR spotlight into a regular white light spotlight, but this can only be done in a non-combat situation.

Take a look at this video here to see the L-4A spotlight in action.

The L-4A spotlight has an aperture diameter of 305 mm, smaller than the spotlights for the M60A1 and the Chieftain. The Chieftain's spotlight, for instance, has an aperture diameter of a staggering 570 mm, and consumes 2 kW of power. This is admittedly quite beneficial for searching for targets, because although the beam itself is only about 570 mm in diameter, dust, water vapor and smoke in the air help dissipate the light and increases ambient light levels, and illuminating a reflective object such as the ground will generate a bigger lit up spot. But despite the huge size and power of the spotlight, the nightsight on the Chieftain has an identification distance of just 1000 m. Despite using a much, much less powerful spotlight, the performance of the TPN-1-43-29 is quite close, with the ability to identify tank-type targets at around 800 m. The passive setting allows the same target to be spotted at ranges of up to 800 m if the ambient light is no less than 0.005 lux, which is the typical brightness of a moonless, starlit night with clear skies. Clarity and spotting distance improves with increasing brightness. The identification distance is expanded to around 1,000m on moonlit nights, and it is possible to spot tanks at distances of more than 1,300 m during dark twilight hours, although low magnification and mediocre resolution complicates viewing beyond that range. This level of performance is on par with the best Western equivalents of the mid to late 60's, but for 1976, the TPN-1-49-23 was simply no longer competitive. It did, however, have light intensification technology, which tanks like the M60 did not have until 1977.

If used as a backup sight, it can be used to identify tank-type targets at up to 3,000m in daylight or more, if the geography and weather permits it. It has a field of view of 6 degrees at 5.5x maximum magnification. Variable zoom allows reduction of magnification to 1x to give the gunner much better general visibility for spotting targets.

The sight has dependent stabilization in the vertical plane with 20 degrees of elevation and 5 degrees of depression. Dependent stabilization means that the sight is technically stabilized, but it piggybacks on the vertical stabilizer for the cannon. Since the cannon has to elevate by +3 degrees for the loading cycle, the gunner will usually lose sight of his target immediately after firing, so he will be unable to observe the "splash" so that he knows how much elevation correction he needs to apply. The commander can see, of course, but that's not a very convenient way of doing things.


Though the cover can be removed and the sight used during daytime, the light intensification channel must never be activated, because excessive light input will overload the sight unit and possibly damage it. In accordance with this, the aperture has shutters linked to the trigger unit. Upon firing, the shutters automatically close to shield the unit from the intense flash of cannon fire at night. These shutter may also be manually opened and closed via a handle.

TPN-3-49

Complementing the primary sighting complex from the original T-80 all the way to the T-80U is the obligatory nightvision sighting system, which also functions as the backup sight in the event of the destruction of the main sighting unit.

Although it still only features a 1st Generation IR imaging module, the TPN-3-49 boasts a more advanced (and also bulkier) design than the earlier TPN-1-49-23. More specifically, it features a more sensitive IR receiver module, enabling it to see farther using the same L-4A "Luna" IR spotlight as its predecessors. The spotlight is mounted coaxially with the cannon and follows it in elevation and depression via simple mechanical linkages.

There are three selectable reticle settings for the viewfinder, one for each ammunition type; APFSDS, HEAT, and HEF. Each reticle different ranging scales for the gunner to input range data onto. Gunnery is reduced to its most basic level when using the TPN-3-49. Determining the range to the target is done by comparing the size of its profile with the size of the chevron, which is a rudimentary and rather imprecise method of rangefinding that is still implemented in the most modern sighting systems as a fallback option for when everything else fails. Unfortunately, this is the only way for the gunner to conduct rangefinding. However, it was determined that since the viewing distance was so short, it didn't really matter anyway.



The sight is not connected with the 1V517 ballistic computer. Laying the gun onto the target is done by lining up an adjustable horizontal line to an appropriate graduation on the range scale, which also moves the chevron up and down. So for instance, if a tank-type target is located 900 m away, the gunner places the horizontal line between the "8" mark and the long mark, which drops the chevron slightly. By using the handgrips to lay the dropped chevron up and back on target, the cannon is given proper supraelevation and a ballistic solution is formed.

The maximum identification distance of a tank-type target is 1,300 meters in the active channel, and 850 meters in the passive channel under lighting conditions no brighter than 0.003 lux. This figure will increase as ambient light gets brighter, but an important point to take is that the amount of ambient light needed to achieve the 850 m identification distance - 0.003 lux - is lower than the 0.005 lux standard by which the performance of the TKN-3 is measured by. This essentially means that on the same night, the gunner will be able to see about a half kilometer further than the commander. Although the TPN-3-49 appears to be less capable than the gunner's IR sight on the British Chieftain with its 1000-meter nominal identification range, it's worth noting that that system uses a 2 kW spotlight that has a diameter of around 570 mm.


In accordance with its function as a night sight, TPN-3-49 features an automatic internal shutter that blocks off the light intensifier device via an electric signal from the trigger on the gunner's handgrips. This is to protect it from burning out from the flash of the cannon firing, as the device is extremely sensitive and a bright flash of light so close to the sight will generate a sudden spike in voltage large enough to fry the vacuum tubes. Of course, the image produced may also be bright enough to cause eye damage to the gunner. The light amplification channel must never be activated during daytime, because daylight is already bright enough to permanently damage the sight.

The armoured housing for the sight head of the TPN-3-49 can be distinguished by its small and squarish front profile, and the small bolt at each corner of the armoured cover. It is taller than the housing for the TPN-1-49-23.

T-80B (1978)

1A33 Fire Control System

1G42 Sight

The T-80B was equipped with the more advanced 1A33 fire control system featuring the 1G42 primary sight with the associated fire control sensors and computers together with the Kobra missile system. The 1G42 sight has an accelerometer and an independent gyroscopic sensor enforcing an independent 2-axis stabilization system. Supplementing all that is the 1V517 digital ballistic computer, the 1B11 crosswind sensor and the 1B14 ambient temperature sensor. Atmospheric data from the sensors is fed to the ballistic computer together with range data to form a firing solution. The system also includes a Delta-D sensor which records the distance traveled by the tank after the lasing of a target. This allows the tank to accurately engage a target without re-lasing it even if the tank has approached or receded from the target.

Unlike the rather outdated 1A40-1 fire control system used in the T-72B, the 1G43 features fully automatic lead calculation and automatic gun superelevation. What this means is that the aiming chevron at the center of the sight picture remains static as the FCS adjusts the elevation to account for ballistic drop and adjusts the orientation of the turret to account for lead. The sight is not displaced sideways as the gun is adjusted for lead, thanks to the 2-axis stabilizer in the 1G42 - the horizontal stabilizer rotates the sight aperture to compensate for the shifted orientation of the turret, thus allowing the gunner to maintain an unchanged view of the target.

The diagram below shows the markings and indicators in the sight picture. The digital readouts at the bottom of the sight picture show the type of ammunition currently loaded and the distance to the target. Beside the digital readouts are two LED light bulbs. The one on the left lights up to indicate that the cannon is ready to fire, and the one on the right lights up when the commander designates a target.

Besides the digital component of the targeting system, there is a range scale at the top meant for manual gunlaying in an emergency. It works just like in earlier gunsights like the TSh2B-32 for the T-54; the gunner turns a dial and the range scales move up and down while the horizontal line running across it stays fixed. The only difference between the old TSh2B-32 and the 1G42 is the range scale for APFSDS ammunition - marked "Б" in the diagram above - is not vertical, but split into a diagonal line instead. This is because the ballistic drop of 125mm APFSDS is too small to be represented on a vertical range scale - the scale would appear as a solid black bar with indiscernible markings and range values.

The horizontal sliding line lying on the vertical range line (labeled as "Шкала Боковых Поправок") moves up and down together with the range scale as the dial is turned. When the dial is turned for a farther distance, the sliding line slides down, and vice versa. The intersection point between the horizontal and vertical line forms the crosshair when firing in manual mode.


The crosswind sensor is shown in the photos below. It uses a rather old-fashioned windmill-type anemometer to measure windspeed and not a digital hot wire anemometer in later designs with a meteorological mast. Since the 1B11 anemometer can only be affected by crosswinds, the device cannot measure headwinds and tailwinds. It device is heated to prevent failure by icing and to enable windspeed measurements in low temperature environments.

GTN-12

The Kobra gun-launched guided missile is guided to its target via a radio command link, and the radio signal is transmitted by the GTN-12 antenna unit located directly in front of the commander's cupola. The transmitter is linked to the sighting system using the 9S416-1 control system, which translates the shifting of the point of aim in the 1G42 sight to generate a command signal for the missile, thus forming a SACLOS guidance regime.

The infrared bulb at the tail of the 9K112 missile is detected and tracked by the 1G42 sight. Due to the use of radio guidance, it is possible to jam the 9K112 missile during its flight. However, it does not appear that such equipment was developed or fielded by the expected enemy so this appears to be a very minor drawback.

T-80U

1A45 Fire Control System

1G46 Sight

The 1G46 sight is rather large and bulky, weighing in at 115 kg. The sight has independent two-plane stabilization with a range of elevation of -15 to +20 degrees, and a range of traverse of 8 degrees to either side. According to Ukroboronexport, the minimum laying speed in both axes is 0.05 degrees per second, which equates to the ability to lay the chevron with a maximum error of 0.88 meters at a distance of 1,000 meters in both the vertical and horizontal planes. The sight has two magnification settings to choose from: 2.7x or 12x.

The layout of the sight is almost exactly the same as the 1G42. The only differences are in the shape of the stadia rangefinder, the size of the horizontal sliding line for manual aim, and the shape of the digital readouts and the indicator lights at the bottom of the sight picture. A photo of the reticle can be seen below (credit to Stefan Kotsch).

The 1G46 sighting complex also comes with a liquid cooled laser beam encoding and transmitting unit attached to the right hand side, unlike the T-72B, which used its 1K13-49 auxiliary sight for this purpose. This probably explains the heavier weight of 1G46 compared to other Soviet sighting complexes. The missile control unit is pictured below.

Other than the inclusion of the encoded laser projection unit, there is not much difference between the 1G46 and the 1G42. The independent stabilization system for the sight head has a good accuracy by Soviet standards, but the sighting line drift can be problematic. If the tank is moving at a high speed of around 25 km/h, the sight may drift away from the original point of aim at a rate of 0.2 mrads per second, so in the space of five seconds, the chevron will have moved 1.1 meters off target. This can be easily corrected by twitching the hand grips just slightly, but this does mean that the gunner has to be mindful. It is not known if there is automatic drift compensation.

T01-P02-01 "Agava-2"

The revelation that new Western developments in thermal imaging technology was producing compact thermal imaging sights that were rapidly outstripping the capabilities of light intensifying night vision sights resulted in new research on creating analogous devices to up the ante. Thermal imaging was not an unknown scientific field for the Soviet military industry during the 1980's as prototype imaging systems for tanks had already been developed by the early 80's and installed on a small number of T-80 tanks on a trials basis. Working prototypes were already available for testing purposes by the early 80's, but problems with establishing mass production held up the development of thermal sights in the Soviet Union for a long time. In this sense, Soviet tank technology was behind the West by almost a decade, in both technological achievement as well as industrial know-how.

Only the command variant models of the T-80U, the T-80UK, had the Agava-2 installed due to their prohibitively high cost. The widespread introduction of this technology was not only a manufacturing challenge, but it would have bloated the already incredibly high price of the T-80 tank series. Due to the lack of widespread service compared to the basic T-80U, it was not common to find T-80UK tanks during the 1990's, but still, the Agava-2 had a few interesting quirks that are worth investigating.

Instead of an optical eyepiece or a "fishbowl" lens like the type found on the Abrams, the viewfinder on the Agava-2 was a 384x288p CRT monitor screen similar what the PZB-200 used. The sight itself is only capable of limited optical zoom, from 1.8x to 4.5x. To attain a greater degree of magnification, electronic interpolation (digital enhancement) is used to generate 18x zoom.

(Not actual resolution of viewfinder screen)

Under the highest magnification setting, the sight facilitates the identification of a tank-type target at a distance of around 2500 m under clear weather conditions. While the sight itself may be more than serviceable enough at combat distances, the low resolution and small size of the monitor makes it difficult to distinguish targets from one another at longer distances.

The commander is also provided with a 4.33" CRT monitor which feeds from the Agava-2, giving the commander a duplicate image of what the gunner is seeing.

The armoured housing that protects the sight aperture can be distinguished from the one for the TPN-3-49 by a hinge on the left of the armoured window cover. The window can be opened from within the tank via a simple pullstring, as you can see below. This particular T-80 is an experimental T-80B equipped with the Agava-2. The armoured housing is identical between all models.

STABILIZERS

By 1976, it would have been unimaginable to not include full two-axis weapons stabilization as a prerequisite for the T-80. Being a developmental offshoot of the T-64A, the original T-80 came with the same two-axis stabilizer system. The layout of the stabilizer components remained the same as the T-64A, which was also true when the 2E42 was introduced, as shown in the drawing below.

2E28M, 2E28M2

The 2E28M two axis stabilizer is used in the original model T-80 being the newest stabilizer at the time of its development, while the 2E28M2 was used for modernized T-80 models with the TPD-K1. The stabilization system is precise enough to guarantee hits on tank-sized targets at distances of up to 1.6 kilometers while the tank is travelling cross country, as indicated by Soviet tank gunnery exercise norms.

The hydroelectric generator for the hydraulic gun elevation mechanism is pictured below.

The maximum turret rotation speed is 18° per second. It would take it a minimum of 20 seconds to do a complete 360° revolution. An inherent shortcoming of hydraulic stabilizers is their risk factor in case of turret penetration. Hydraulic fluid is highly flammable, and it would most likely cause and spread an internal fire very quickly. This is an especially serious concern to the T-80, since the layout of its autoloader does not shelter the ammunition from burning fluids. 2E38M2 uses MGE-10A, a type of mineral hydraulic oil with very low temperature sensitivity, having an operating range of between -65°C to 75°C. The entire system operates at 7.25 psi. This is quite dangerous, as with all hydraulic systems, because hydraulic oil may spurt out from burst tubes at high speeds, spraying large portions of the interior with the flammable liquid.

The entire stabilization complex is centered around the use of a gyrostabilizer meant for measuring angular velocities in order to enforce corrections. The weight of the sum of all the components is 320 kg.



Vertical Stabilizer:

Maximum elevating speed: 3.5° per second
Minimum elevating speed: 0.05° per second


Horizontal Stabilizer:

Maximum turret slew speed: 18° per second
Minimum turret slew speed: 0.07° per second

The hydraulic fluid reservoir for both the 2E28 is mounted to the roof of the turret, just adjacent to the commander's head. It has a clear window with replenishing indicators. Maintaining the stabilizer and its associated subsystems is the gunner's responsibility.

2E42M1

The components shown in the photo above are the amplidyne generator for the turret traverse motor, the hydraulic arm for the vertical stabilizer with its attached hydraulic pump, and the turret traverse motor itself, from left to right.

The photo below shows all of the components for the turret rotation mechanism. From left to right: Amplidyne generator, relay control box (to control rate of rotation), and the electric motor for turret traverse.

The 2E42M1 combines a hydroelectric turret rotation and stabilization drive with a hydroelectric cannon elevation and stabilization drive.

  
The hydroelectric pump for powering the cannon elevation system is located under the cannon's breech, and the hydroelectric pump for turret traverse is installed in front of the gunner, behind his sight unit.

Amplidyne generator for 2E42M1 visible in the upper left corner of the photo

Besides being more precise than the 2E28M-2, the horizontal stabilizer motor is also more powerful, giving the turret on the T-80U a quicker rate of rotation.

Vertical Stabilizer:

Maximum elevating speed: 3.5° per second

Minimum elevating speed: 0.05° per second

Horizontal Stabilizer: 

Maximum turret slew speed: 24° per second

Minimum turret slew speed: 0.054° per second

The sum total of the components belonging to the stabilization system weighs 320 kg.

AUTOLOADER

Being a direct offshoot off of the T-64 family, the T-80 inherited its autoloader directly from its parent design. The official designation of the autoloader is the MZ ("Механизмом Заряжания") which directly translates to "Loading Mechanism", identical to the T-64A, but an updated version with new radio-guided gun-launched missile compatibility rapidly supplanted the original variant when the T-80B entered service shortly after the original T-80. Another updated version with an improved electronic system was used in the T-80U. In all of its variations, the MZ autoloader is of a hydroelectric type, utilizing hydraulic actuators to drive almost all of its moving parts. Between it and the AZ autoloader used on the T-72 series of tanks, it is quicker to load and has a considerably larger capacity, but it also has its own peculiarities and drawbacks. As usual, the gun needs to be lifted to a fixed angle to line it up properly for the loading mechanism to ram fresh rounds into the chamber, and this is done by the hydraulic vertical stabilizer piston of the cannon. To hold it in place, the gun is hydrolocked.

The autoloader carousel rotation mechanism is hydraulic, as is the lifting arm that brings the ammunition cassettes up to the ramming position behind the gun breech. The hydraulic lifting arm for the ammunition cassettes is located on the false floor of the turret crew cabin, as you can see in the photo below. A total of 2.2 liters of MGE-10A hydraulic fluid is used in the autoloader.

The ammunition cassette lifting arm can be seen in action in this video of the autoloader of the T-64.

Both the gunner and commander are provided with controls to the autoloader. The gunner's autoloader controls can be seen below. Photo credit to "coast70" from the QIP.ru photo sharing platform. The dial on the left allows him to select his desired ammunition type, and the big black button on top initiates the loading sequence. The white display panel on the right indicates the status of the autoloader.

The two-part cartridges are stowed in an 'L' position in the autoloader carousel, thus forming a basket around the turret ring. The basket carousel is mounted directly to the turret ring and moves with the turret, but it rotates independently of the turret when cycling for new ammunition. The turret ring of all T-80 turrets are designed with two ball bearing race rings: one between the turret and the hull and one between the turret and the autoloader carousel. This can be seen in the drawings below.

The autoloader carousel rotates at a rate of 26 degrees per second, and some additional fractions of a second are needed for the system to brake when the desired ammunition type is reached. When loading ammunition into the autoloader, the ammunition type is indexed by setting the appropriate type in the autoloader loading control box located next to the commander. Turning the carousel by one step takes up 12-15% of the total loading time, and turning it by three steps takes up 17-22%

The propellant charges are held vertically and the projectiles are held horizontally. This arrangement exposes the vulnerable propellant charges vertically, and without any armour protection to speak of (the aluminium cassettes are too thin), this layout increases the probability of ammo deflagration in the event that the armour of the tank is perforated from the front, sides and rear. The propellant charges are the most volatile half of the two-part ammunition, and storing them in such close proximity to the turret ring area of the tank where the majority of shots land would not bode well for the tank if the armour was perforated. Indeed, the thought of being surrounded by a ring of volatile propellant is hardly comforting for the crew in the turret. However, the layout of the autoloader carousel also allows the maximum possible quantity of ammunition to be stored within the geometric constraints of the turret ring diameter. The layout of the autoloader also gives the crew slightly more vertical space compared to the AZ autoloader of the T-72.

The cartridge cassette is composed of two lightweight aluminium trays connected by a hinge.

The second half of the cassette is raised by the hydraulic elevator mechanism acting upon an angled lug in front of its hinge point. The same elevator supplies most of the force propelling the cassette upwards, and it also helps support the weight of the cassette when it is unfurled. The first half of the cassette has an eccentric mounting point for the system of levers of the alignment mechanism to act upon.

As you can see in the GIF above, the two halves of the cassette split apart and release the cartridge from its bonds just a moment before the ramming cycle begins.

One drawback of the MZ autoloader is that it takes up some horizontal space because the ring of ammunition is installed within the diameter of the turret ring so the crew stations are narrower than the turret ring diameter would suggest. According to factory drawings of the T-64 (Object 432), the diameter of the crew cabin in the turret is 1590mm, although it may be worth noting that the Object 432 is armed with a 115mm D-68 gun and not a 125mm D-81 gun, and that the autoloader carousel holds 30 rounds of the slightly more compact 115mm cartridges instead of 28 rounds of 125mm cartridges. However, the difference is very small. The internal diameter of the turret crew cabin is less than the width of the hull and much less than the tank's turret ring which is 2,162mm in diameter. The photo below shows how the autoloader carousel occupies a significant amount of space and reduces the internal diameter of the crew compartment. The backrest visible in the lower half of the photo is the gunner's seat, and the gun is to the right.

One of the distinguishing features of the MZ autoloader is its ammunition capacity - it holds a remarkable 28 rounds of ammo, more than the 22 rounds carried on the T-72, more than the 22 rounds in the ready racks in the bustle of an M1 Abrams (105mm), much more than the 17 or 16 rounds in the M1A1 Abrams (120mm), and nearly double that of the 15 rounds on the Leopard 2. The average loading speed of the MZ autoloader is easily on par with an average human loaders, and even outpaces the AZ autoloader of the T-72 by around one second under ideal circumstances. According to a T-80 technical manual, the combat rate of fire is 7-8 rounds per minute. This is corroborated by the T-64A and T-64B/B1 manuals, which give a combat rate of fire of 8 rounds per minute from the same autoloader and the same fire control system. However, the autoloader itself is capable of loading a round and returning the gun to aim on a target of the gunner's choosing in only 6 seconds if the gunner chooses not to change ammunition types, so the maximum technical rate of fire is actually 10 rounds per minute. A translated cyclogram of the steps in the loading cycle is presented below:

This cyclogram comes from the document "Автоматические Системы Заряжания Вооружения Бронетанковой Техники" (Automatic Gun Loading Systems of Tanks) published by the Russian Ministry of Defence, 2011.

The average time between shots is 7.1 seconds to 19.5 seconds, but the 19.5 second loading time is only true if the gunner is switching from one ammunition type to another and the desired ammo type happens to be the last one in the carousel. Since the autoloader carousel can only rotate in one direction, this forces the carousel to rotate over 26 other rounds (347 degree rotation) at a rotational speed of 26 degrees per second to reach the last one in the carousel. By dividing 347 degrees by 26 degrees per second, we find that the rotation of the autoloader carousel takes up 13.5 seconds, plus a few fractions of a second to account for the initial acceleration period and the braking time. The loading of the cartridge itself takes just under 6 seconds to complete and the total time taken adds up to 19.5 seconds. However, 19.5 seconds is not realistic with a standard combat load of ammunition during real combat, as the autoloader will choose the first round of ammunition of the type specified by the gunner. If, for instance, the tank carried a 3:3:3 ratio of APFSDS, HEAT and HE-Frag (which it does not), the autoloader carousel would have 9 shots of each type loaded plus one extra round. Assuming that the gunner began with APFSDS and decided to switch to HEAT, the carousel would need to rotate over 8 other APFSDS shells to reach the first HEAT shell. If he began with APFSDS and decided to switch to HE-Frag, the carousel would need to rotate over 17 other shells to reach the first HE-Frag shell. This is not quick, but the time needed to rotate over 17 rounds is still much less than 26 rounds. If the gunner switches from HE-Frag back to APFSDS, the carousel will need to rotate over 8 rounds to reach the first APFSDS round. Unless the ammunition is loaded in an unusual order and autoloader is operating under the most unusual circumstances, it would be impossible for a loading cycle to take as long as 19.5 seconds to complete.

Tankers often came up with their own solutions on how to solve these problems, and one of the solutions was to load ammunition in a repeating pattern, as detailed by Major Mikhail Chobitok in this excerpt from "T-64: Main Battle Tank" by M. Saenko:


"Затолкать артвыстрелы в конвеер МЗ можно в любой последовательности. Но в бою, время на заряжание пушки – дороже золота.

Поэтому, если при загрузке равномерно чередовать боеприпасы по типам, то и поиск (а соответственно и заряжание) их будет быстрее.

Конвеер МЗ при заряжании вращается только в одну сторону. Если загрузить сначала все бронебойные, потом все кумулятивные, потом все осколочные, то, выбрав на заряжание любой тип, будешь ждать, пока конвейер прокрутит все и доберется до нужного. А для эффективной стрельбы вероятность нахождения боеприпаса в конвейере должна быть одинаковой! Вот и думай танкист, как тебе быть… Пришлось повозиться."


Translated:


"Loading the rounds into the MZ autoloader conveyor can be in any order. But in battle, the time to load the gun - more expensive than gold.

Therefore, if the ammunition is evenly arranged in alternate ammo types, then the search for the ammunition (and therefore loading) will be faster.

The conveyor when loading the MZ autoloader rotates in one direction only. If you load at first all armor-piercing, then all HEAT, then all HE-Frag, then, having chosen on loading any type, you will wait until the conveyor scrolls everything and gets to the correct one. But to effectively fire the probability of finding ammunition in the conveyor should be the same! Think as if you were a tanker... you have to tinker."


In other words, the ammunition was arranged thusly:


APFSDS - HEAT - HE-Frag - APFSDS - HEAT - HE-Frag - APFSDS - HEAT - HE-Frag


This makes it quicker for the gunner to switch from one ammunition type to the other, but when the ammunition is arranged in such a way, the carousel must rotate over two shells to get to the same ammo type for every loading cycle. So if the gunner needed to fire at the same target with the same type of ammunition twice in a row (such as if he were engaging a tank with APFSDS, for example), the loading cycle would take 7.5 seconds. This matches the claimed 7.5 second reload speed implied by the combat rate of fire according to the manual. This is not a coincidence. The average minimum time between shots of 7.1 seconds is achieved under the assumption that the autoloader always loads the next round in the carousel (6 seconds) and another 1.1 seconds is taken to aim the gun. This may be how the 8 RPM rate of fire figure is obtained. However, Chobitok does not explain how he or his compatriots accounted for the fact that the combat load of T-64 tanks did not contain an equal ratio of the three ammunition types, which was further complicated by the advent of gun-launched "Kobra" missiles in 1976.

Of course, this was not necessarily how all T-64 crews did it. It is reasonable to expect that this became a technique that was later passed down by word of mouth to fresh arrivals at specific tank companies, but it may not be institutional knowledge that was taught nationally to all recruits in tank schools.


Either way, it should be quite obvious by now that the rate of fire may not be the same in all situations, even if all tank crews adhered strictly to the same method of loading ammunition into the carousel. One must not forget that it is often the skill of the crew that determines how much time passes between each shot. Both the gunner and commander do their part to seek out potential threats through their respective vision devices, but the commander must also identify the target upon discovery and he must convey this information to the gunner. The gunner must then verify that he is seeing the same object as the commander, and then proceed determine the range to the target. On the original T-80 with the TPD-2-49 optical coincidence sight, rangefinding can take four seconds or more, depending on the skill of the gunner, but the average time needed to find a target using the tank's vision devices is rather more hazy. As such, the actual time needed to take the first shot is invariably longer than 7.1 seconds, and only subsequent shots on the same target - so the time needed to find and range the target is eliminated - can occur at the theoretical maximum speed of 6 seconds.

The autoloader is insensitive to scorching heat, freezing cold, nor does it care how fast the turret is spinning, thanks to its impeccable sense of balance. It does not matter if the tank is rocking around like a bucking bronco at 50 km/h over the most gutted dirt paths. The autoloader will still load a shell in the specified time, every time. The common argument that the autoloader can be "knocked out" by hard impact or a hit on the tank's armour is fallacious - a hit on the tank's armour that does not fully penetrate yet is powerful enough to disable the autoloader would also be powerful enough to concuss the people inside the turret and effectively disable the gunner and commander as well as the loader. From an economics standpoint, an autoloader makes sense too. Manufacturing an autoloader on an assembly line costs a certain amount, but training a loader would take at least around 3 months and cost more, and a shoddily trained candidate will not be able to perform "up to spec". Of course, it can be pointed out that depending on unskilled labourers to assemble the autoloaders would also produce the same effect, but really, but shoddy craftsmanship would most likely manifest as reduced reliability, not as reduced loading speed.

REPLENISHMENT 

When reloading the cassettes, these halves must be locked together with a special key before the cassette can be indexed and lowered back into the autoloader. This is shown in the photo below.

Ramming is conducted by a rigid chain actuator located at the back of the turret, directly behind the breech of the gun. The rammer passes through the open back end of the cassette, shoving the propellant and the projectile assembly into the gun chamber in one swift motion and immediately retracting so that the spent shell stub of the previous round can be placed into the cassette before it is folded up back into the autoloader carousel.

According to the manual, the process of restocking the entire combat load of ammunition including non-autoloader stowage can take between 25 and 30 minutes to complete, while replenishing the ammunition reserves of the autoloader carousel takes between 13 to 15 minutes. Reloading the autoloader is a simple process. All that happens is that the normal loading cycle is reversed, so instead of shells being rammed into the breech of the cannon, the cassettes are raised into position, where they are loaded with a fresh round, then lowered back into the autoloader.

One of the peculiarities of the autoloader is that the entire row of cartridges stowed around the perimeter of the turret ring completely isolates the driver from the rest of the crew. This makes it practically impossible for the commander to communicate with him without using the intercom system or for the driver to evacuate the tank through the turret. The latter requirement is quite a serious one because the driver cannot exit through his own hatch if the tank cannon is directly above it. However, the designers were kind enough to create provisions for creating a passage between the driver's station and the turret.

However, even this small provision is extremely flawed. The driver can only enter the turret via a small cutout in the turret cabin, but in order to get through the ring of ammunition, he must first remove two cassettes from the ring. This is done using a special lever, which the driver must secure to a protruding lug at the base of the ammunition cassette and then lift it off its mounting point on the carousel ring. This is quite easy if the cassette is empty but extremely difficult if it is not, considering that the tank's two-part ammunition weighed as much as 33.0 kg in the case of standard HE-Frag cartridges and the driver must perform his task from within the confines of the tank, not to mention that the cassettes themselves add some weight as well. The driver would need to deposit the two dismounted cassettes onto the turret cabin floor, preferably with assistance from the two crewmen in the turret.

LOOSE STOWAGE

Whereupon the entire load of ammunition in the autoloader has been expended, the crew has the option of replenishing it with extra cartridges from racks placed here and there all around the interior of the fighting compartment of the tank. The original T-80 and the T-80B had a rather small reserve capacity of just 7 cartridges, stowed in the hull in a conformal fuel tank-cum-ammo rack located on the port side of the hull, just behind the driver's seat.

Five shells of any type and seven propellant charges can be stowed in the racks, and another two shells may be strapped onto the exterior of the rack to complete the set. These two extraneous shells each have a metal cup bolted to the floor of the hull to hold them in place.

The new T-80U and its turret had space to store 10 extra cartridges. Stowing extra ammunition in the turret was a substantial security risk with the chance of catastrophic ammo detonation jumping up by two times, since now the turret and not just the hull was potential cause for a popped turret. So as mentioned before in the "Gunner's Station" segment, the crew could, and would have opted not to make use of the racks in the turret.

CANNON

There only ever were a few things in common between the members of the Soviet "tank triad", and the cannon was one of them. Like its brothers, the T-80 mounted the 2A46 125mm smoothbore cannon, but along with the T-64, the T-80 was consistently ahead of the T-72 in implementing the latest and most advanced 125mm gun variants.


The initial T-80 was equipped with the 2A46-1 cannon (D-81TM) which was an improved variant of the original 2A26 (D-81T). The T-80B was equipped with the 2A46-2 cannon which featured the necessary electronic equipment to fire guided missiles.

AMMUNITION

This section will only contain details on the missiles compatible with T-80, as the basic types of ammunition available to the T-80 are identical to what was available to the T-72. Therefore, if you wish to read about APFSDS, HEAT and HE-Frag ammunition, please head over to the T-72 article.

MISSILES

The relevance of gun-launched guided missiles designed for tank cannons of a limited bore diameter is arguable, to put it mildly, but what is most certainly true is that they were prohibitively expensive and their value against new NATO composite armour arrays was questionable at best until the new tandem charge Refleks-M missile arrived. Besides, the tank would have had very few chances to exploit the incredible range offered by its arsenal of missiles due to the infrequency of encountering large expanses in Central and Western Europe. The huge flatland fields of the Ukraine were optimal, but the Red Army was certainly not planning on being on the defensive.

However, missiles are not used just for shooting at ground targets. Airborne targets are fair game as well. In fact, besides the Germans, Soviet tank crews are the only tankers that are trained to engage low-flying aircraft as part of their curriculum. The only difference was that West Germans were taught to attempt to use APDS shells to do the job. With speedier 125mm APFSDS ammunition, the T-80 was capable of this too, as mentioned before, but the likelihood of scoring a hit isn't very high.

The missiles used for the T-80 are split into two halves; rocket motor and fuse for the front half, and warhead plus guidance receiver for the back. The two halves are snapped together by the straightening motion of the loading cassette as it is moved into the ramming position.

9M112 "Kobra"

From Stefan Kotsch's website

The 9M112 missile had only a single charge warhead placed at the front half of the missile. The shaped charge liner was possibly made of aluminium. An improved version with a copper warhead was also in use, designated 9M112M. The basic 9M112 version was introduced in 1976, while the improved 9M112M was introduced in 1979. The main improvement of the 9M112M over the basic 9M112 was the use of the new 9N129 warhead with a 20% higher penetration. 9M112M entered service in 1978 and began mass production in 1979. The 9N129 warhead uses OKFOL for a more powerful blast effect and for a more energetic cumulative jet.

The placement of the shaped charge warhead at the front of the missile severely limits the standoff distance. This has a negative effect on its penetration power, and renders the missile no more powerful than the typical 125mm HEAT shell.


Penetration:

9M112: 250mm at 60°

9M112M: 300mm at 60°

The missile is soft-launched out of the gun barrel by the 9D129 propellant charge.

The 9M112 missile is guided by radio command and directed by the GTN-12 radio antenna. The "Kobra" system is fully integrated into the 1A33 fire control system and works together with the 1G42 sight, which the gunner uses to designate the aiming point. The integral laser rangefinder in the 1G42 sight is also used to determine the distance to the target in order to determine the appropriate mode of guidance. At engagement distances of 4 km, the missile does not fly at a level altitude. Kobra climbs to 3 to 5 meters above the bore axis of the tank and cruises at this elevated altitude until it reaches within 600 to 800 meters of the target, whereupon it descends back to cannon level and continues until it hits the target. The system uses range data from the 1G42 sight in order to plan a flight path and guide the missile toward the target when it enters the final phase of its flight. This enables it to avoid striking bushes, low hills and other natural obstacles throughout its long journey to the target. Together with the low firing signature of the missile, this feature may also decrease the reaction time of the target, as the elevated cruising altitude of the missile puts it above the direct line of sight of a potential target and the missile is also more difficult to see when framed against the backdrop of the sky.

In the direct fire more, the missile travels at a level altitude and reaches the target in this manner. This direct fire mode is generally intended for use against helicopters, but it is also intended as an emergency mode for shooting high priority targets that appear suddenly at close range if the tank already has a missile loaded.

3UBK20 

9M119 "Refleks"

The 9M119 "Refleks" laser beam-riding missile is similar to the 9M119 "Svir" used in the T-72B, but with an increased range of 5,000 meters instead of 4,000 meters. Guidance is accomplished by the integrated 9S517 laser beam unit on the 1G43 sighting complex.


The missile is soft-launched by a 9Kh949 reduced load piston-plugged ejection charge, giving the missile some momentum before the rocket motor kicks into action. The piston plug is designed to properly seat the missile in the chamber, but its primary purpose is to protect the laser beam receiver at the base of the missile from propellant gasses. The total weight of the 9Kh949 charge is 7.1 kg.

The missile itself has an efficient layout with the rocket motor placed in the middle, the warhead at the very rear, and the control surfaces and mechanism at the front along with the fuse at the tip. The large distance between the tip of the missile and the warhead means that the warhead is given a large standoff distance without the need for a special standoff probe. The layout enables the 125mm missile to have a comparable flight range as the 127mm ITOW missile, and superior armour penetration performance, but in a much more compact package. With 700mm of penetration, "Refleks" is a much more serious weapon with a much better chance of defeating the new generation (at the time) of NATO tanks like the Leopard 2 and M1 Abrams, albeit from the side. The chances of defeating such tanks from the front with this missile are rather slim.

The missile uses a solid fuel motor, with four nozzles arranged radially. Flight stabilization is maintained via five pop-out tail fins with curved and angled surfaces to impart a slow spin onto the missile, while steering is accomplished by the two canard fins at the front. These are operated pneumatically, so the more corrections the gunner makes while the missile is mid flight, the less responsive the missile will be over time, though the gunner will have to be tracking a very difficult target like a moving helicopter for this to become noticeable.


Missile Diameter: 125mm
Wingspan (Stabilizer Fins): 250mm

Shaped Charge Diameter: 105mm

Maximum Engaging Distance: 5000 m
Minimum Engaging Distance: 100 m

Penetration: 700mm RHA

Hit Probability On Tank-Type Target Cruising Sideways At 30 km/h:
100 m to 4000 m =  >90%

Flight Distance Time:
4000 m - 11.7 s

3UBK14M

9M119M "Refleks-M"

The appearance of "Refleks-M" gave the T-80 the newfound ability to more confidently destroy newer NATO tanks like the M1 Abrams and Leopard 2, given that their protection requirements for the frontal arc were limited to single charge missiles equivalent to the Milan. With its tandem charge warhead, "Refleks-M"


The precursor warhead has a cone diameter of 64mm, essentially just as large as a 66mm LAW warhead, and almost equally as powerful. Unlike some tandem warhead designs where a shallow shaped charge of low power is used as the precursor to create a hole in an ERA panel through which the primary charge can pass, the precursor warhead on the "Refleks-M" is large and powerful enough to initiate an ERA panel prior to the detonation of the primary warhead, thus considerably limiting its effects on the primary warhead. However, the downside is that the flier plates of the ERA panel can still fly into the path of the shaped charge jet from the primary warhead, so the effects of ERA may not be fully eliminated. One advantage in having a powerful precursor shaped charge is that it is also effective in compromising armour other than ERA due to its high penetration power. For a precursor charge built for breaching a hole into an ERA panel rather than initiating it, the shaped charge is too weak to have any significant effect on complex multilayered armour as it would fail to perforate even the front plate of the armour array. On the other hand, a large 64mm shaped charge can penetrate the initial layers of a multilayer array and leave the back layers of the armour vulnerable to the primary charge.

Overall, the combination of features found on the "Refleks-M" missile makes it a suitable weapon against legacy tanks uparmoured with ERA including a number of M60A3 and AMX-30B2 tanks as well as the new standard NATO tanks of the second half of the 1980's, namely the M1A1 Abrams and Leopard 2A4.


Penetration:
700 - 750mm RHA (Without ERA)
650 - 700mm RHA (Behind ERA)

COAXIAL MACHINE GUN

The T-80 is equipped with the ubiquitous PKTM general purpose machine gun as a supplementary coaxial weapon.

The PKTM is mainly distinguished from the earlier PKT by the smooth barrel as opposed to the fluted barrel of the PKT. Internally, the PKTM and the PKT differ in the same way that the basic PK and PKM models differ. When the PKM replaced the PK on the production lines in 1969, the production of the original PKT also halted. As such, the T-80 was only officially equipped with the PKTM as the tank only entered service in 1976. The machine gun is fed with 250-round boxes of ammunition with an additional four boxes carried inside the turret cabin next to the commander's feet for total ammunition capacity of 1,250 rounds. The commander is responsible for reloading the machine gun.< br/>
7BZ-3 API (armour-piercing incendiary) rounds with the B-32 bullet and 7T2 API-T (armour-piercing incendiary tracer) rounds with the T-46 bullet are linked in a 4:1 ratio. The machine gun has a cyclic rate of fire of 700 to 800 rounds per minute. The cartridges are held in 50-round belt segments which are linked together. The coaxial machine gun can be fired either by depressing the trigger button on the gunner's handgrips, or by pressing the emergecy manual trigger button located on the trigger unit installed at the back the receiver of the machine gun.

In the case of the T-80U, the trigger button on the PNK-4S control module can also be used to fire the machine gun.

The machine gun is mounted to the right of the main gun, and protrudes from a pill-shaped port which provides vertical space for gun elevation. Since it is mounted alongside the main gun, it receives all the benefits of the stabilization system.

ANTI-AIRCRAFT MACHINE GUN

It should be clear by now that the T-80 (Object 219 sp.2) has remarkably little in common with the T-64A despite the fact that it was descended from it. The anti-aircraft machine gun installation is just another one of the details that distinguish the two types from each other.

The ZU-64 closed-hatch type anti-aircraft installation was being tested from April 13 to September 10, 1971, and it started appearing on T-64 tanks beginning from the T-64A obr. 1972 onwards. However, the ZU-64 had a flawed design and several of the flaws were conceptual and not technical. As such, a new anti-aircraft installation designated the ZU-219 was designed for the Object 219 and it was later evaluated in comparative trials held in Cuba, from February 1 to September 1, 1973. It was tested alongside the already established ZU-72 open-hatch type installation of the T-72, as well as the experimental ZTPU-2 and experimental ZU-62. At the end of the trials, it was recommended that all three Soviet main battle tanks should standardize on the ZU-219. However, the same questionable political factors that led to the creation and adoption of the infamous trio of main battle tanks prevailed here, and the T-72 retained its flawed ZU-72 installation while the T-64A retained its ZU-64 installation and the ZU-219 was shelved.

Following these developments, the vastly inferior ZU-80 anti-aircraft installation somehow became the final product that ended up being used on mass-production model of the T-80. The ZU-80 is an open-hatch type installation much like the ZU-72, but it is a unique and rather flawed design.

Unlike the ZU-72, the anti-aircraft installation is mounted directly onto the commander's cupola and not on a separate race ring or skate ring, but unlike the ZU-64, the cupola is not motorized so aiming must be done manually. The location of the machine gun mount had the rather unfortunate effect of completely disrupting the balance of the cupola, forcing the commander to put in more effort when rotating the cupola especially since he does this using the handlebars of his TKN-3 periscope. This issue is compounded if the tank is in motion, and especially so if the tank is moving over rough terrain. Due to the height and length of the machine gun, the tilting and swaying of the tank creates moments of force which the commander must fight when attempting to turn the cupola. The unbalanced loading of the cupola also makes it very difficult to rotate when the tank is on a slope. The ZU-64 would have the same issue, but it has a motorized horizontal drive which eliminates this problem entirely and give the commander a much more pleasant overall experience.

Firing the machine gun is done by pressing a trigger paddle located on a handlebar to the left of the gun mount. Elevation is done using a flywheel located on the right of the gun mount. The range of elevation is from -5 degrees to +75 degrees. Traverse is done by simply shifting the entire cupola manually. Although the design of the gun mount is clearly not ideal, to put it mildly, it should not be a serious issue when the commander is outside the hatch and using the machine gun. From outside the hatch, the imbalance of the installation would not be any different from a machine gun on a skate ring mount since the center of gravity of the machine gun itself is actually over the cupola ring even though the machine gun has a cantilever mount.

The NSVT is a respectably accurate, rapid-firing heavy machine gun chambered in the 12.7x108mm cartridge. It fires at a cyclic rate of 700 to 800 rounds per minute. Against slow-moving or hovering helicopters, the NSVT may occasionally prove marginally useful in theory, especially if the helicopter in question has poor or no cockpit and fuselage protection, although firing at attack helicopters with a machine gun is generally an exercise in futility except under unusual circumstances. Firing at aerial threats is facilitated by a K-10T collimator sight attached to the machine gun cradle. Firing at ground targets can also be done with the K-10T by using the burst-on-target (BOT) method, but using the machine gun's original iron sights are more appropriate for the job. The NSVT operator is trained to fire in 10-round bursts.

The K-10T collimator sight projects crosshairs onto the angled glass pane. A tinted glass block is placed in front of it to allow the operator to fire more effectively when facing the sun. When not in use, the sight is turned off and the protective cover is closed. The protective cover must also be closed when fording rivers to prevent water damage.

The relatively high cyclic rate of the NSVT compared to its peers like the DShKM and M2HB is useful when dealing aerial threats as the increased density of fire is useful when attempting to hit fast-moving aerial targets or at least deter the pilot from approaching the tank. Unlike the DShKM, the NSVT lacks a muzzle brake but has a flash hider instead which makes it distinctly more pleasant to shoot, especially in low light conditions. The operator is not only much less likely to be blinded by the muzzle flash, but he is also spared from the concussive effect of muzzle blasts.

The machine gun is fed with 100-round boxes. One box is placed on the machine gun mount and another two boxes are stowed outside the turret next to the commander's cupola for easy access. Three hundred rounds of 12.7mm ammunition is carried in total. The 100-round boxes are heavier and bulkier compared to the more familiar 60-round ammunition boxes provided for the NSVT of the T-72, making it slightly more time-consuming to reload, although this is compensated by the simple fact that the increased ammunition capacity reduces the need to frequently reload. However, by stowing the ammunition boxes externally, it is possible for them to be damaged by gunfire and artillery splinters. This is a drawback shared by all previous Soviet main battle tanks and medium tanks with an anti-aircraft machine gun, including the T-54, T-62, T-64, and T-72. In this case, there was no alternative as the commander's hatch is far too small for the commander to retrieve such large ammo boxes from inside the tank, transfer it through the hatch opening and onto the machine gun mount.

A mixture of B-32 (steel-core AP-I), B-30 (steel core AP) and BZT-44 (steel-cored API-T) is carried with the non-tracer and tracer rounds linked in a 4:1 ratio.

The ZU-80 anti-aircraft installation has been an integral part of the T-80B tank and can currently be found even on the latest T-80BVM tank models, as seen in the photo below.

T-80 tanks have been observed with a strange metal loop with track links affixed to the back of the cupola. This is apparently a solution to the imbalance of the cupola, though it is clear that this solution does nothing to address the root cause of this problem. Although it seems to be reasonably successful as a counterweight, it also adds more weight to the cupola which partly offsets its primary benefit.

The T-80U continues to feature an anti-aircraft machine gun, but the method of mounting the NSVT is rather bizarre. Instead of a conventional ring or skate mount or perhaps a direct installation onto the rotating cupola like on the ZU-80, the NSVT on the T-80U is mounted on any one of three pedestals welded to the turret roof. This can be seen clearly in the photo below (credit to Vitaly Kuzmin).

There is one forward and to the right of the commander's cupola (as shown in the photo above), one forward and to the left, and another directly behind the cupola. Alternatively, there is another pedestal behind the gunner's hatch. Elevation is done using a flywheel and traverse is done purely by physical force. The machine gun is still fed from large 100-round boxes and the stowage location of the reserve ammunition boxes remains the same.

This unusual scheme has its own small advantages, but for the most part, this system is a detriment to the usefulness of the machine gun. For one, the fixed installation of the machine gun limits the aiming sector to only about 90 degrees forward and slightly to the right, and that's with the commander leaning out of the hatch. To aim sideways, the commander must exit his hatch and sit out on the turret roof, open to all and sundry. Aiming backwards is not possible unless the machine gun is installed on the rearmost pedestal, which is not feasible when already in combat, as the machine gun itself already weighs 25 kg. The photo below shows the machine gun mount being demonstrated.

The NSVT mount also includes a canvas belt catcher to prevent sections of belt from landing in front of the commander's pericopes and obstructing them.

1ETs29 Remote Weapons Station

In 1987, the all-new T-80UD received a new remotely controlled, electrically assisted machine gun mount integrated into a redesigned commander's cupola. It is independently vertically stabilized, and derives horizontal stabilization from the counterrotation mechanism of the cupola. The range of elevation permitted by the mount is extremely generous, spanning from -15° to +85°.

Aimed fire on ground targets is conducted using the PNK-4 combined sighting system through the eyepieces of the TNK-4S. The commander can shift from observation to shooting at the flick of a toggle switch, whereupon the reticle of the TKN-4S changes to a graduated one with suitable markings and the stabilizer for the NSVT mount is slaved to the sight. The commander is then able to use the sight elevation handgrip to operate the machine gun up and down by +20° and -4° down respectively.

If the commander wishes to fire at a target situated higher than the tank, he may use the PZU-7 anti-aircraft sight installed at the front left quadrant of the cupola. Using it disengages the machine gun from the TKN-4S, but the use of the thumbswitch is retained for aiming and firing. The sight has a maximum elevation of +70° and maximum depression of -5°.

Thanks to vertical stabilization, the commander has the ability to engage targets while on the move.

The main merit of the new weapon system is of course the fact that the commander does not need to expose himself to fire the machine gun, thus isolating him from harm, but unfortunately, the new design is fundamentally not different from the much older ZU-64 installation. Unlike the ZU-219 design, 1ETs29 remote weapon system does not allow the commander to fire the machine gun manually from an open-hatch, thus constricting his ability to react to air attack in the same manner as the ZU-64.

PROTECTION

There is no doubt that it was the T-80 series that had the most sophisticated sighting systems and the best firepower, and the T-80s were one of the fastest tanks on Earth to boot, but nothing is perfect. For the T-80, the crux of the matter is the lackluster effort made in utilizing the best glacis armour available at the time, and the turret armour was surpassed by the T-72B in 1983. Regardless, the members of the T-80 family still had a warranty of virtual invulnerability to the vast majority of weapons deployed by NATO with a superiority margin of several years' worth of technology.

And let's not forget to mention that the secret to not blowing up is to not get seen. The T-80 was equally as short as its big brother the T-64 and its cousin the T-72, though it did get a little taller when the new Object 476 turret was fitted in 1985. Otherwise, the T-80 and T-80B from 1976 and 1978 respectively were both nearly as short as the novel Stridsvagn 103 by a margin of just a few centimeters. And one of the features that made the Strv. 103 so attractive to the Swedes was, of course, its low silhouette.

Still, getting seen might be inevitable even at the best of times, and not getting seen might not even be possible sometimes, so when the tank does get hit, the only thing that's worth anything is the steel between the crew and certain death.

T-80 (Object 219 sp.2)

The steel grade used for the construction of T-80 hulls was BTK-1. In 1976, this was the new standard steel grade. T-64 and T-72 tanks transitioned from 42 SM medium hardness steel to BTK-1 during that year.

Not only was the very first T-80 model from 1976 often visually indistinguishable from the earlier T-64A, they also shared many components and even had identical glacis armour geometry and configurations, although they also differed greatly. The entire upper glacis armour array measures 205 mm in actual physical thickness, but the 68° slope multiplies this figure to 547 mm in line-of-sight (LOS) thickness. The configuration is as follows:

80 mm HHA > 105 mm Glass Textolite > 20 mm HHA

The areal density of this armour array at the constructional angle of 68 degrees is 2,616 kg/sq.m, so the mass of the armour array is equivalent to a solid steel plate with a thickness of 333mm. Of that, 520 kg/sq.m is from the glass textolite interlayer and the remainder is from the steel plating. A highly detailed examination of this composite armour design is available on the T-72 article. You can view it here. The main difference between this armour and the armour of the T-72 ural is that BTK-1 high strength, high hardness steel is used as opposed to the medium hardness 42 SM steel, which is equivalent to normal HHA grade steel. As such, the protective value of the T-80 armour is higher by an undetermined amount. In all likelihood, it is somewhere between the older 80-105-20 armour with RHA steel and the 60-105-50 armour array of the T-72 Ural-1 and T-72A.

One of the distinguishing features of the T-80 armour that separates it from the T-64A is related to the implementation of three medium-sized periscopes installed in the upper glacis for the driver as opposed to a single large periscope in the upper glacis and two smaller ones embedded in the hatch. The visibility from the new scheme was good, but to accommodate the three periscopes, the cutout in the upper glacis armour had to be widened considerably. Since this cutout was a weakened zone, the increase in its size was not profitable, to put it mildly. The large cutout can be seen in the photo below (credit to VoLLanD).

This design flaw continued to plague the T-80 series to this day. It is not possible to eliminate this weakened zone without a fundamental overhaul to the armour geometry and the driver's station.

In 1979, the original T-80 underwent a modernization program to bring it up to the level of the T-80B, which sported a revised design that was better optimized against emerging Western long rod penetrators. As a result, it was decided to weld a high hardness steel appliqué plate to supplement the base armour. The pre-fabricated plates were sent to depots where they could be installed as part of regular scheduled maintenance, along with a few other minor things added as part of the modernization program.

T-80B (Object 219R)

While the original glacis armour configuration was more than enough to contend with perhaps all 105mm ammunition of the APDS variety found on the other side of the Iron Curtain, by 1976, the design was already teetering on the brink of obsolescence. By that point, only the T-64B and T-80 were still using the older upper glacis armour design which was first used in the original T-64 (Obj. 432) that had been mass produced since 1964. Keeping in step with these developments, the new T-80B obr. 1978 (Object 219R) used a more optimized armour design with improved performance against long rod APFSDS rounds. According to Alexey Khlopotov (known online as "Gur Khan"), the configuration is as follows:

60mm HHA -> 100mm Glass Textolite -> 45mm HHA

This new array was based on the design developed for the T-72 Ural-1 and T-72A and was nominally equivalent in overall thickness and in the distribution of layers. This armour layout is also considerably more resilient compared to the 80-105-20 design retained in the T-64B. According to Andrei Tarasenko, the upper glacis armour of the T-80B was equivalent to 380mm RHA whereas the armour of the T-72A was equal to 360mm RHA. It is worth noting that many of his numbers lack an internal consistency and sometimes contradict each other, so it is inadvisable to take these numbers at face value. For an in-depth examination of the 60-105-50 armour, please refer to Tankograd's T-72 article, Part 2. In short, the use of BTK-1 instead of normal RHA steel for the front plate and back plate of the armour increases the effectiveness of the armour by not only offering greater resistance due to its increased toughness, but also by increasing the transverse loading experienced by a long rod penetrator passing through the plate. This increases the stresses experienced by the rod, making it more effective at breaking apart long rod penetrators. An indirect effect of this phenomenon is that the glass textolite interlayer sandwiched between the two steel plates will have an increased efficiency.


In 1980, the steel grade used for the production of T-80 hulls was upgraded to BTK-1Sh. BTK-1Sh is a grade of high hardness, high strength steel produced by electroslag remelting (ESR), giving it higher hardness without sacrificing ductility. Further confirmation of the use of BTK-1Sh rolled steel plates in T-80 tanks comes from a Soviet study on the weldability of this steel. In general, BTK-1Sh is recognized as a general purpose high strength steel, suitable for welding and for manufacture in thick plates of up to 85mm, or perhaps more. Depending on the thickness of the plate, the hardness of the steel ranges from 400 to 450 BHN.


In 1983, the recent revelations on newly emerging 105mm APFSDS technology - embodied by the Israeli M111 Hetz - prompted the need to add additional armour in order to proof the hull against the M111 round at shorter range. As such, a 16mm appliqué plate was welded directly onto the upper glacis. The plate was cut in such a way that it could be fitted directly onto the surface of the upper glacis and not interfere with the mine plough mounting points and the tow hooks. Steven J. Zaloga claims in page 23 of "T-80 Standard Tank: The Soviet Army's Last Armored Champion" that the appliqué armour plate is 20mm thick, but this is not corroborated by any Russian or Soviet sources.

During this time, a new 5-layer glacis armour array was under development as a response to the growing threat posed by the new West German 120mm smoothbore cannon. When the T-80BV arrived in 1985 with the improved armour array, the obsolescent T-80B could not be left behind, so there was a need to bring its standard of protection up to the level of the new T-80BV without changing the armour layout entirely as that was not possible without dismantling the tank hull. Once again, the solution was to weld additional armour onto the existing array, but this time, the new appliqué armour plate was 30mm thick. The thick 30mm plate has the same cutout shape as the earlier 16mm plate, so the only way to distinguish them is to simply check the thickness by eye. The photo below shows one example of a T-80B modernized to T-80BV standards. Notice the much thicker weld seams joining the appliqué plate to the upper glacis.

As a result of this modernization, the total thickness of steel in the upper glacis armour array was increased to 135mm while the thickness of glass textolite remained the same at 100mm. The areal density increased to 3,347 kg/sq.m of which 2,829 kg/sq.m was steel. The mass of the armour became equivalent to 426mm of solid steel. It is interesting to note that the five layered armour design of the T-64BV was developed using the 60-100-45 layout as the basis. The same 30mm high hardness plate was used, but instead of welding the high hardness plate to the surface of the 60mm front plate, the 30mm plate relocated to the interlayer. The thickness of the original 100mm glass textolite interlayer was reduced accordingly to 70mm, and it was divided into two layers, thus forming the now-familiar 60-35-30-35-45 design. Due to the increased efficiency of the five layer armour design, the upper glacis armour of the T-64BV is more resilient than the upper glacis of a modernized T-80B.

The T-64B was modernized to T-64BV standards with an appliqué plate of the same thickness, but it still retained the old 80-105-20 array and thus lagged behind the T-80B in this aspect. Due to the low efficiency of the thin 20mm steel back plate of the older design, the overall efficiency of the upgraded armour was not high. For the most part, the burden of eroding a long rod penetrator would be largely taken up by the thickened front steel plates (30mm + 80mm) as opposed to a pair of plates with an optimal distribution of thickness. As such, the modernized T-80B armour had a non-trivial edge over both the T-64B and the T-72A while differing very little in weight.

The turret of the T-80B is very similar to the turret of the T-72A, but is very slightly thicker (by around an inch or so) in certain areas. The transition from the turret of the T-64A to the "Kvartz" turret which was originally developed for the T-72A seems surprising given that the T-80 is descended from the T-64 and not the T-72, and especially since the turret appears somewhat crude compared to the enigmatic "Combination K" ceramic armour of the T-64B, made from two rows of sintered silicon carbide balls suspended in solid cast steel. However, the level of protection offered by the "Kvartz" composite turret was not worse and the production process was very simple and cheap compared to the "Combination K" design.

The gradient of the decline in armour thickness at the sides of the turret is also slightly less steep than the T-72A turret. The "Kvartz" insert also reaches slightly further back along the side of the turret. However, this turret design is not necessarily better protected than the T-72A turret across a wide frontal arc, since the curvature of the T-80B turret is more rounded as opposed to the teardrop shape of the T-72A turret. Because of this, more of the sides and less of the frontal cheek armour will be exposed when the turret is viewed from a side angle of 30 degrees or more. By compensating for the curvature with thickened armour, both turret designs offer a very similar level of protection across the frontal 70 degree arc.

The "Kvartz" turret design was carried over to the T-80BV (Object 219RV) but it was eventually replaced by the more advanced T-80U (Object 219AS) turret which incorporated NERA elements. In 2017, the T-80BVM model was unveiled. The modernization program makes use of Soviet-era stocks of ageing T-80B and T-80BV and gives them a new purpose as specialized cold weather tanks. One of the improvements from the modernization was the installation of Relikt explosive reactive armour on the frontal arc of the turret and on the upper glacis. Due to the use of the "Kvartz" filler as an integral component in the casting process for the composite armour in the turret, it is not possible to upgrade the armour of the T-80B and T-80BV. The hull armour also cannot be upgraded for a similar reason. As such, the only increase in protection is derived from Relikt ERA.

T-80BV (Object 219RV)

In 1985, the newly introduced T-80BV came endowed with a heavier, but more effective double sandwiched laminate array design for the upper glacis. Instead of a single layer of glass textolite between two steel plates, the new array is composed of two thinner layers of glass textolite sandwiched between three 50mm steel plates. The steel plates are made from BTK-1 high strength, high hardness steel like before. This new array has a physical thickness of 220mm and a LOS thickness of 587mm at the constructional angle of 68 degrees. The areal density of this array is 3,490 kg/sq.m, which is equivalent to a solid steel plate with a thickness of 444.6mm. The turret of the T-80BV was the same as the T-80B, which was itself very similar to the turret of the T-72A and featured a similar "Kvartz" filler. The turret was not improved except for the installation of Kontakt-1. As such, the principal difference between the T-80BV and the T-80B is in the upper glacis armour and in the installation of reactive armour. The new upper glacis armour array is as follows:

50 mm RHA - 35 mm Glass Textolite - 50 mm RHA -> 35 mm Glass Textolite - 50 mm RHA

The additional protection against KE attack was achieved with the addition of a center steel layer and in the revised distribution of layer thicknesses. At a slope of 68 degrees, the LOS thickness of the steel alone is 400mm. The two glass textolite layers are not as thick as in the previous models, but the increased thickness of steel led to an increase in protection against shaped charges all the same. Compared to the similar 5-layer array of the T-64BV, the armour of the T-80BV is thicker and heavier, having a total thickness of 150mm of steel distributed equally in three layers as opposed to 135mm of steel distributed in the order of 60-30-45. It is known that the optimal thickness of a steel front plate is 1-2 rod diameters, and considering that the diameter of the latest 105mm and 120mm APFSDS rounds were all less than 30mm, the 50mm front plate of the T-80BV armour array lies squarely within the range of optimal plate thicknesses, and so does the 60mm front plate of the T-64BV, so the T-80BV does not have an advantage or disadvantage in this respect. The only advantage of the T-80BV armour lies in the thicker 50mm center and back plates inside the armour array, which are thicker than the 30mm and 45mm center and back plates of the T-64BV by a non-trivial amount.

It is likely that the 50-35-50-35-50 armour array of the T-80BV is more efficient than the 60-35-30-35-45 array of the T-64BV. Conceptually, the design of the T-64BV armour array is only an evolution of the simpler three-layer array of the T-80B. On the T-64BV, the option of creating an entirely new configuration with a new distribution of steel layer thicknesses was not pursued. Rather, a 30mm plate of high hardness steel was simply added to the existing 60-100-45 design created for the T-80B as the center layer - it was mentioned by Andrei Tarasenko in an article that the central steel plate in the five layer armour of the T-64BV had an increased hardness which increased the efficiency of the armour array. It is not known if the 50mm center layer of the armour of the T-80BV is made from a special grade of high hardness steel as well, or if all three steel layers are made from BTK-1. Based on Soviet and Russian studies on the topic, it is highly desirable to maximize the hardness of the center layer and increase the thickness of the steel back plate as this increases the efficiency of the armour array against long rod penetrators.


On page 297 of "Particular Questions of Terminal Ballistics" 2006 (Частные Вопросы Конечной Баллистики), an analysis of a five-layer composite armour arrays with steel and textolite reveals the inner workings of this type of armour and the methods of optimizing it. Analysis of experimental test results reveals that the penetrator rod experiences transverse loads in an oscillating pattern as it travels through a five-layer armour array. This is caused by the large differences in the physical characteristics of glass textolite and steel. The large oscillating amplitude of the lateral forces and torque generates strong bending stresses in the rod, thus weakening the rod and reducing its penetration power. The rod also experiences strong shock loads during each impact with the front surface of the steel plates. For a five layer design with three steel plates, three shock events are experienced by the rod. Deformation of the rod tip is observed throughout the penetration process, as the tip is deflected upwards by strong lateral forces when it impacts the front surface of the steel plates (impact phase) and then it is deflected downwards when it emerges from the back surface of the steel plates (breakout phase). The deformation of the tip during the breakout phase is caused by the asymmetry of material thickness above and below the rod. The asymmetry of material thickness generates an asymmetric load on the rod, causing the tip of the rod to deflect towards the path of least resistance.

Figure 5.27 (below) illustrates the physical changes experienced by the penetrator rod as it travels through an experimental five-layered steel and glass textolite armour array sloped at 65 degrees. The impact velocity of the rod is 1,450 m/s. As you can see in the first graph on the upper left corner, the transverse force imparted onto the long rod penetrator (Fy) is in the upwards direction when it travels through the front steel plate (1) and center steel plate (3) and then normalizes at the end of its travel through the steel back plate (5). Note that the rod is heavily deflected downward when it exits the back of the center steel plate. The upwards transverse force imparted during the penetration of the steel back plate (5) is only just enough to counteract this deflection. As you can see in the first graph, the direction of the transverse force on the rod shifts drastically as it enters the breakout phase on the center plate, plateaus for a short while, and then shifts further as the rod penetrates the second glass textolite layer (4). The sudden shift in transverse loading is amplified by the large forces involved, which creates huge stresses in the rod. The magnitude of forces is especially huge compared to the forces experienced by the rod as it travels through the front steel plate and first glass textolite layer. Furthermore, it can be seen that the resistive force along the axis of the penetrator (Fx) constantly increases as the penetrator progresses through the armour array, reaching its peak at the center layer, then fluctuates until the projectile reaches the steel back plate where the resistive force decreases until the penetration stops. Note that resistive force is proportional and opposite to the force imparted by the penetrator rod and is dependent on the mechanical properties of the target material.

From these results, it can be surmised that increasing the hardness of the center steel plate (for any given thickness) will maximize the stress on the rod and increase its deflection. Allocating more armour mass towards the center layer will also be advantageous. Increasing the thickness of the steel back plate is also desirable in order to better absorb the remainder of the penetrator and to further deflect its trajectory upwards, thus increasing the effective thickness of the back plate and imparting greater stress on the rod.

Breakout effects will indirectly generate additional losses in the penetration power of a long rod penetrator: during the period immediately after the rod emerges from the back of a steel plate, the tip of the rod has a low velocity relative to the rest of the rod and the tip will be deflected due to asymmetric loading. The tip will also continue to erode (read: lose mass) due to the release of accumulated stresses. When the tip of the rod impacts the next steel plate, the combination of low velocity and non-optimal shaping causes the tip to ricochet off the surface of the plate. This is a source of additional losses in rod material and structural integrity.

The glass textolite layers have a relatively minor effect compared to the steel layers, but the breakout effects also enhances the efficiency of the glass textolite: the penetration efficiency of a eroded penetrator rod with a deformed tip is reduced, and conversely, the efficiency of the glass textolite layer is increased.Still, it was identified that the protection value offered by a multilayered steel-glass textolite array is mainly derived from the spacing of the steel plates into multiple layers, but extensive testing on tank armour as well as special targets reveals that the efficiency of the glass textolite layers can be equal to steel of its own weight (mass efficiency coefficient of 1.0) when incorporated in an optimal multilayer design sloped at 65 degrees, and even exceed the mass efficiency of steel by 3-5% in some cases. The high obliquity of the upper glacis of the T-80BV (68 degrees) implies that the glass textolite layers in the armour have a mass efficiency coefficient of not less than 1.0.

This can be seen in the second graph on the right column. The bottom curve in the graph (u/V0) shows the velocity of the rod tip at the point of contact with the armour. The long rod penetrator travels at a lower velocity in the steel layers than in the glass textolite layers, but a constant deceleration can be observed.

On a side note, it is stated in the book that a homogeneous glass textolite block can have a mass efficiency exceeding homogeneous steel armour by 1.3 to 1.5 times when impacted at a flat angle (by an unspecified type of projectile). However, the arrangement of glass fibers in the glass textolite gives it anisotropic properties, such that the efficiency of the material is vastly degraded when it is sloped. Furthermore, the enhanced strength and ductility of modern tungsten alloy and depleted uranium long rod penetrators makes them much tougher which inhibits the erosion of the rod as it penetrates glass textolite, thus rendering glass textolite largely ineffective as a barrier against modern APFSDS threats if not incorporated into a heavy multilayered array. Conversely, the low toughness of tungsten carbide increases the efficiency of glass textolite, which provides a justification for the high thickness of glass textolite used in the previous armour designs for the T-64, T-72 and T-80.


In pages 410-427 of "Particular Questions of Terminal Ballistics", a multitude of different array layouts with different ratios of layer thicknesses were tested against tungsten alloy long rod penetrators of differing aspect ratios to find the optimal distribution of thicknesses and the optimal obliquity. The results are particularly interesting as they can be compared to the five-layer design of the T-80BV.

The three-layer array shown below has a 1.2:2.12:1.0 ratio of layer thicknesses with steel front and back plates with a glass textolite interlayer. The ratio of thicknesses is equivalent to the 60-105-50 armour layout. This layout was placed at an angle of 68 degrees and was tested against two types of tungsten alloy long rod penetrators with equal lengths but different diameters (aspect ratios: UPE-3 = 11.0, UPE-4 = 12.0) and compared to other layouts. The calculated magnitude of force imparted on the penetrator in the vertical plane and along the axis of the rod is shown in the first two graphs, and the change in velocity of the penetrator at the tip and at the tail (in separate curves) is shown in the third graph.

As you can see for the 60-105-50 armour layout, the penetrator experiences large destabilizing effects inside the steel front plate, but remains almost completely steady inside the glass textolite interlayer, and then experiences a downward deflection as it impacts the steel back plate before becoming deflected upward. More specifically, it can be observed that the long rod penetrator is strongly deflected upward during the initial phase of its impact with the front plate, and then the rod is strongly deflected downward during the breakout phase before equalizing as it travels through the glass textolite interlayer. The large forces involved and the violence of the shift in vertical deflection shows that the long rod penetrator experiences huge transverse loading during its penetration of the steel front plate, but there is practically no transverse loading as it penetrates the glass textolite interlayer. Furthermore, the velocity of the penetrator rod tip drops sharply as it penetrates the front steel plate but barely changes as it travels through the glass textolite layer and the resistive force along the axis of the penetrator (Fx) is very small - up to 20 times less than the resistive force from the steel plate. This is in marked contrast to the constant deceleration of the rod tip and the high resistive force that was observed in the five-layer armour.

The interaction between the rod and the steel back plate is also interesting, as the gradient of the deflection curve implies that the rod would continue to be deflected upward as it penetrates deeper into the plate. Conversely, a back plate of low thickness (such as the 20mm back plate found in the T-80 obr. 1976, in some T-72 models and in all T-64 models prior to the T-64BV) is clearly inefficient because the downward deflection of the rod would reduce its effective thickness. This observation is supported by other studies confirming that the 20mm back plate of the older 80-105-20 armour design was inefficient against long rod penetrators, which was the original incentive for the shift to the 60-105-50 design on the T-72 in 1976 and for the shift to the 60-100-45 design on the T-80B in 1978.

Overall, the performance of the simpler three-layered armour is clearly worse compared to a seven layer armour which was able to obtain much better results by simply redistributing the same materials into more layers. Two different long rod penetrators were fired at the seven-layer target: UPE-3 and UPE-4 with aspect ratios of 10.0 and 12.0 respectively. As shown in the graphs, the transverse loading on the rod oscillates violently in direction and magnitude, imparting huge stress on the penetrator. Furthermore, the velocity of the penetrator is constantly reduced as it travels through the armour array, which implies that the efficiency of the glass textolite layers is much better as they have a much greater contribution to the erosion of the long rod penetrator.

These experimental armour designs used only normal RHA steel plates, but it is well known that increasing the hardness of the front plate leads to a corresponding decrease in the performance of a long rod penetrator attacking the armour. The effects of increasing the hardness of the other steel plates in the armour array also tend to be positive. Considering all the available information, it is understood that the upper glacis armour of the T-80BV is of an efficient layout and its mass efficiency greatly exceeds that of a monolithic steel plate of equivalent mass, and based on the information gathered so far, it is obvious that the low mass efficiency coefficient implied by the low numbers attributed to the upper glacis armour of the T-80BV like "430mm RHA" are simply impossible as the efficiency of the five-layer armour is obviously higher than the simpler three-layered armour used in preceding tank models.


Adding on to that, the drawing below, shared by Militarysta (Jaroslaw Wolski) on the Polish militarium.net forum, details the formation of "lips" at the edges of the perforated plates due to the asymmetrical distribution of forces on the back surface of the plate during the penetration process. The "lips" are pushed into the path of the shaped charge jet or the long rod penetrator by a shock wave travelling through the non-metallic filler and rebounding off the neighbouring steel plate. The drawing are from MBB, a German company where the illustrious Dr. Manfred Held worked during the 70's and developed his first explosive reactive armour.

However, this appears to be a secondary effect at best. The contribution of the "lip" effect is reportedly quite low.


Because of the increased thickness of steel, the armour of the T-80BV is undoubtedly more resilient than the T-64BV design but the difference in mass efficiency is less clear as there are very few sources of information on how this affects the overall function of the armour array. According to Andrei Tarasenko in an article, the upper glacis of the T-80BV was equivalent to 430mm RHA and the upper glacis of the T-64BV is equivalent to 410mm RHA.


Having a mass of 444mm in terms of thickness of solid steel, the calculated mass efficiency coefficient of the T-80BV armor according to Tarasenko's figure is 0.97. On the other hand, the mass of the T-64BV armour is equivalent to 404mm of solid steel so the calculated mass efficiency coefficient of the array is 1.01. Perhaps the ratio of layer thicknesses in the T-64BV design is better, but the low mass efficiency of both designs compared to monolithic homogeneous steel is highly dubious. Indeed, if these numbers are correct, then a single monolithic steel plate (mass efficiency coefficient of 1.0) would be more efficient than the multilayered composite of the T-80BV which obviously cannot be true. Furthermore, Tarasenko also claims that the armour of the T-72A modernized with a 16mm appliqué plate is equivalent to 405mm RHA, but the T-72A armour is equivalent to 403mm of steel in weight so the mass efficiency of the armour would ostensibly be 1.0. Needless to say, it is extremely unlikely that the 5-layer array of the T-80BV would perform worse than the appliqué armour stop-gap solution used on the older and simpler 3-layer design of the T-72, especially since Tarasenko states in another article that the new 5-layer armour of the T-64BV was superior to the modernized T-64B armour with a 30mm appliqué plate. It is even less likely considering that the T-80BV uses an improved BTK-1 steel and not normal RHA steel like the T-72. In general, the low efficiency implied by Tarasenko's numbers is contradicted by the simple fact that simple two-layered design with a normal RHA steel front plate (not improved BTK-1 steel) and glass textolite back plate already has a mass efficiency coefficient of 1.0 against long rod tungsten penetrators with an aspect ratio of 10.0 and 12.5. A simple three-layer 80-105-20 design would be unquestionably better if not at least approximately equivalent, and a five-layer design such as the T-80BV array with a more optimized distribution of steel plate thicknesses simply cannot have a mass efficiency coefficient of less than 1.0.

Therefore, these numbers must be grossly underestimated by some amount. It is much more likely that the equivalent armour protection value of both the T-80BV and T-64BV is worth around 500mm RHA or more against a long rod penetrator, with the T-80BV being the more resilient of the two due to the higher steel thickness and better distribution of steel. At the very least, the higher thickness of the center layer in the upper glacis array of the T-80BV compared to the T-64BV begets a higher mass efficiency. Under the assumption that the T-80BV armour must be more efficient than the 60-105-50 armour of the T-72 (ME coefficient of 1.12 established earlier in this article), then the effective thickness must be equivalent to 497mm RHA against long rod heavy metal alloy APFSDS rounds at the very minimum. A mass efficiency coefficient of 1.25 to 1.3 would constitute a reasonable estimation given all available information. It is somewhat more difficult to predict the durability of the armour against shaped charges, but it must be worth more than 600mm RHA based on the 1.35 mass efficiency coefficient of the original 80-105-20 armour array. By multiplying 444mm with the reciprocal of 1.35, we get 600mm. Due to the improvements made over the old design, the real value of the armour should be somewhere between 600-700mm RHA but not higher.

On its own, this level of protection was sufficient for the anti-tank missiles and grenades of the 1970's, but more powerful weapons were being fielded rapidly in large quantities on the other side of the Iron Curtain. By 1985, the largest threats were the MILAN 2 and the TOW-2 which would have been enough to defeat the basic upper hull armour. The installation of Kontakt-1 was absolutely mandatory for the tank to withstand such powerful attacks. The 5-layer design was carried over to the T-80U which used Kontakt-5 instead of Kontakt-1.

Kontakt-1

The addition of Kontakt-1 ERA armour added just under 1.2 tons to the original weight of the tank. The layout of the blocks was not optimal, to put it mildly.

Installing Kontakt-1 on the tank is easy but tedious. Each reactive armour block is attached to the surface of the hull, turret and sideskirts using a pair of bolts. The ease of installing and replacing the blocks meant that the entire modification could be done as part of regular scheduled maintenance. However, simplicity comes at a price in this case. The rubberized side skirts are rather fragile, and can be quite easily knocked off when the tank is travelling through densely wooded areas, or perhaps traversing obstacles in urban sprawl. With the added burden of a few dozen Kontakt-1 blocks mounted onto it, it only gets easier to accidentally knock the side skirts off. The photo below shows a "naked" T-80BV with the necessary provisions for mounting Kontakt-1.

A detailed examination of Kontakt-1 is available on the T-72 article. Please access it here.

T-80U (Object 219AS)

The T-80U carried over the 5-layer glacis array from the T-80BV but differed by having built-in Kontakt-5 reactive armour instead of the less versatile Kontakt-1, although a few early T-80U samples had Kontakt-1 installed. Because the protection level of the underlying composite armour was not changed, the overall armour system was rendered obsolescent in short order by the appearance and later standardization of tandem warheads on many anti-tank weapons in the early 90's, although it is worth noting that these developments were directly influenced by extensive examinations of ex-Soviet and ex-East German tanks so the task of creating countermeasures to these tanks was made much simpler. The T-80U itself was notably examined in Sweden, where exact replicas of its turret and hull armour were made along with its complementary suite of Kontakt-5 armour. As a result, weapons like the Panzerfaust 3-IT (900mm RHA penetration behind ERA) could be created specifically to defeat its armour.


The new cast turret installed on the T-80U (Obj. 219AS) is generally quite similar to the previous turret designs of the T-64 and T-80, but differs in the design of the armour insert cavities. Rather than casting the steel turret structure around the non-metallic inserts ("Kvartz" in the case of the T-80B), hollow armour cavities in the T-80U turret are formed during the casting process and the cavities are filled later down the production line, after which a steel cover plate is welded on top to seal the cavity. This was probably done mainly because the inserts could not be used as casting moulds unlike the sintered quartz filler of the T-80B turret, but this feature could also make it much easier to replace spent inserts and mend holes in the cast steel armour.

Another difference is the elimination of the turret roof weakened zones by increasing the height of the turret cheeks, thus increasing the slope of the turret roof to an angle too high for modern long rod APFSDS rounds to defeat. The thickness of cast steel at the gun mantlet zone was also increased, but the zone remained weak compared to the turret cheeks as it was still made from homogeneous steel. The thickness of some parts of the gun mantlet zone was increased to over 500mm, but the armour around the machine gun port (the other side of the turret is also cut in the same way) and the armour in front of the gun mounting trunnions were still quite thin. The drawing below (taken from the btvt.narod website) shows the shape of the armour cavities and the general armour layout of the turret. Note that although the sides of the turret are not sloped back as much as the T-72B turret, it is thicker, so a similar level of protection is maintained.

Externally, the turret appears to be much less rounded than previous Soviet tanks. The vertical slope on the turret face is only 15 degrees - much less than the 25-30 degree slope of earlier turrets. Furthermore, the joint between the roof of the turret and the turret facings is almost at a right angle as opposed to the gradual steep curve commonly observed on earlier turret designs. This reduces the number of weakened zones by some amount and gives the turret a more flattened shape.

The turret cheeks have a total physical thickness of 548mm. The thickness of the armour insert cavity is 260mm and the cast steel front wall is 98mm thick while the rear cast steel wall is 190mm thick. From a 35 degree side angle, the LOS thickness of the turret cheeks is around 600mm, and when viewed directly from the front, the LOS thickness increases to more than 800mm. The armour cavities are sealed with a heavy cover plate that forms the ceiling of the cavity once welded in place. This feature facilitates quick repairs at depots and enables the composite armour inserts to be upgraded over time if desired, unlike previous Soviet main battle tank turrets where the steel structure was cast around the non-metallic inserts. In the case of serial T-64A tanks, the cast steel shell was formed around prearranged sintered silicon carbide balls, and in the case of the T-72A and T-80B, the cast steel shell was formed around the "Kvartz" filler. In these instances, repair or replacement of the composite elements is not possible, and indeed, the older turret design of the T-80B could not be upgraded in the recent T-80BVM modernization beyond simply adding Relikt ERA panels. The T-80U turret does not suffer from the same drawback and can be readily modernized if the situation calls for it.

The armour inserts utilized in the T-80U series evolved over time, but it is known that most turrets excluding later variants used a type of NERA known as cellular polymer armour. Unlike the more common "bulging plate" type of NERA which was used in the T-72B turret as well as foreign tanks like the M1 Abrams and Leopard 2, the cellular armour in the T-80U lacks air gaps, making it somewhat thinner while offering a similar level of protection. At the moment, the author has not yet accumulated enough information on the specific details of these NERA inserts to write an adequately detailed description meeting normal Tankograd standards.

The outline of the cover plates on the turret cheek armour cavities is visible in the photos below.

Kontakt-5

Although even the best 105mm APFSDS shells and the most powerful guided missiles had already been successfully nullified by the introduction of new composite armour and Kontakt-1 explosive reactive armour, there was still the 120mm threat to consider. 120mm ammunition of the early 80's were not a very serious threat in the short term for a variety of reasons, but it was clear that the new weapon had great potential, so serious countermeasures had to be devised. While the M1 Abrams was not armed with the M256 cannon for which it was famous for until the M1A1 upgrade in 1986, the Leopard 2 had achieved IOC in 1979 and had already grown into a thousand-strong contingent by late 1984. The folks at NII Stali did not twiddle their thumbs idly while news of the new NATO tanks trickled in, and thus, Kontakt-5 was introduced in 1985 as an integral component of the new T-80U.


Coverage on the glacis is good, but not for the turret, which is totally unprotected on either side of the gun mantlet. This was done in the interest of the driver's convenience in entering and exiting his station.

British trialing had long ago concluded that it is the turret that sustains the majority of hits when engaging in tank-on-tank combat, a fact corroborated by independent Soviet tank loss analyses during WWII. This is because the lower third of the tank is usually not visible to the enemy due to tall grass and undergrowth, making the turret ring of the tank the perceived center of the tank.

How Kontakt-5 Works

Kontakt-5 was first implemented on a Soviet tank in 1985 on the T-80U. In 1989, Kontakt-5 was integrated into the T-72B as well, but in a different form. The design of the reactive armour differed between the two models, even though they shared the same name and are generally considered interchangeable.

The 4S22 explosive elements in the upper glacis armour blocks are angled in a V-shape similar to the way 4S20 elements are arranged in Kontakt-1 blocks. By having one of the elements angled at a different angle, and air gap is created, allowing the rear flyer plate to be propelled backwards, thus acting on a penetrating shaped charge jet in the in-pursuit regime which is more effective than a head-on regime Furthermore, there is a small air gap between the flat 4S22 element and the base armour, producing the same effects albeit more weakly. Overall, this design should be more effective against shaped charges than normal Kontakt-1 and also more effective than the Kontakt-5 used on the T-72.

An extensive analysis of the mechanism of Kontakt-5 is available on Tankograd's T-72 article. You can view it here: (Link). 

There are two variants of Kontakt-5 employed on the T-80. The upper glacis panels are set at 68 degrees to the vertical plane, and that fact alone makes them extremely potent. However, the turret panels are set at only 50 degrees to the vertical plane. To compensate for this, the panels on the turret are of a bidirectional design. But first, let us examine the upper glacis of a T-80U.

GLACIS

Flyer plates removed

To reduce the likelihood of a chain detonation, each module is separated by a 20mm heavy duty steel partition permanently welded onto the surface of the upper glacis.

Loading and reloading the reactive armour panels is an extremely simple affair, as long as you have a wrench at hand. Each module is filled with eight 4S20 explosive cells, arranged in a pattern of four, stacked two layers deep with the top layer angled using a special bracket as described earlier.

TURRET

Loading the turret panels is as simple as on the upper glacis. However, the flyer plates for the turret panels are not bolted onto a fixed housing. Rather, they are welded to the walls of the support structure frame. As such, replacing the turret blocks flyer plates is less straightforward than replacing the ones on the glacis, as doing so requires welding equipment and subsequently results in a longer turnaround time.

Click to enlarge

Each turret module is composed of a single head-on flyer plate with a thickness of 15mm, with a robust 9mm steel box welded to it to contain four 4S22 explosive cells - two cells side by side, stacked two layers deep. The 9mm rear wall of the steel boxes act as an in-pursuit flyer plate.

While the turret panels on the T-72B obr. 1989 are set at a slope of 68 degrees on both halves, the panels on the T-80U are only sloped at 50 degrees and 55 degrees for the upper and lower halves respectively. The sole advantage to the Kontakt-5 design on the T-80U is that less of the turret ring area is exposed, so the vertical coverage is somewhat better. In terms of horizontal coverage, it is not significantly better than the T-72B even though the individual armour panels on the turret appear to be seamlessly joined whereas the Kontakt-5 panels on the T-72B are clearly separated by gaps. This is because there are null zones between the pockets containing the 4S22 explosive elements, so a projectile impacting the joints between the 15mm front plates will not be able to detonate the 4S22 elements. The only effect is that the projectile must penetrate the 15mm front plate (equal to around 40mm of steel due to the slope) before impacting the base turret armour.

The excellent protective properties of Kontakt-5 implies a very high mass efficiency, as the armour itself weighs very little compared to the amount of protection they provide in terms of steel thickness. For instance, the top and bottom halves of the turret panels have an areal density of 450 kg/sq.m and 500 kg/sq.m respectively according to Swedish data published by Rickard O. Lindström. This is equivalent to 57.3mm and 63.7mm of steel, which is very minor compared to the claimed penetration reduction of 20% claimed by NII Stali, and especially compared to an old NII Stali claim that attributes Kontakt-5 with an armour equivalency of 250mm RHA. In the latter case, the mass efficiency of Kontakt-5 would be nearly 5 times greater than normal steel, and in the former case, the mass efficiency would be 2.3 if the penetration of the APFSDS round was reduced by 140mm (for an APFSDS round with 700mm of penetration).

However, all things come at a cost. In the case of Kontakt-5, its high explosive content and power is also its biggest drawback, as it is perfectly possible for the activation of one module to set off another. The photo below doesn't actually show the aftermath of this phenomenon. It's just for illustration.

SIDE HULL

Without effective measures for protecting the sides of the hull, the tank's speed and agility will be for nothing. 80 mm of steel, even angled at 70 degrees, isn't really worth much against quasi-modern shaped charges or long-rod penetrators. With Kontakt-5 and about a meter and a half of air space, though (depending on the incidence angle), the odds of survival suddenly doesn't seem that bad. With these side hull panels, the T-80 should be immune to hits from most 105mm APFSDS shells within a 70° frontal arc, but this probably goes down to a much narrower 40° arc for 120mm APFSDS. This should include the DM13, DM23, and M829.

ROOF

Besides front facings of the turret, the upper glacis and the side hull, the roof of the turret is also partially protected by proprietary Kontakt-5 blocks.

EFFECTIVENESS

APFSDS ammunition was advancing rapidly, now that the 120mm cannon and the tanks that hosted them were in play. In 1989, the M829A1 was introduced - the best of its type so far. Measuring in at just a hair under 700mm in length, it was the lengthiest and thinnest long rod monobloc shell in the world. It could penetrate around 350mm RHA at 60 degrees at 2 kilometers' distance. Nothing came near it in performance. The M829A2 introduced in 1992 retained the construction of its predecessor except for a modified tip, and it flew faster thanks to better, more powerful propellant. In 1994, they discovered that M829A1 was unable to penetrate the front of the T-80U and T-72B obr. 1989. It was stopped by...

Kontakt-5.

And on that bombshell, let's take a look at what sort of measures are in place to preserve the tank in case it does get penetrated.

FIREFIGHTING

3ETs11-2 "Iney" Firefighting System

To prevent the spreading of internal fires in the engine and crew compartments, the 3ETs11-2 "Iney" halon gas quick-acting firefighting system was installed, with the driver-mechanic as the primary operator. The system can operate in two modes; automatic and semi-automatic. In the automatic mode, the system reacts immediately to a fire in either the crew compartment or the engine compartment and acts upon the flame regionally, meaning that the system activates specific fire extinguisher nozzles to put out the flame, as opposed to just flooding the entire compartment. In the semi-automatic mode, the system can still automatically detect a fire but instead of immediately activating the fire extinguishers, the driver-mechanic is alerted via the P11-5 control and signal unit placed just in front of him. The decision as to what the next course of action should be is deferred to him.

P11-5

There are 12 TD-1 thermal sensors strategically placed in the engine compartment and crew compartment. The ones in the crew compartment are attached just above the floor of the hull, and aimed mostly at the floor. You can see one of them in the picture below, just right of the three fire extinguishers attached to the 3ETs11-2 system.

The firefighting system reacts regionally when a rise of temperature to 150°C is detected in the crew compartments and engine compartments. The three PPZ fire extinguishers are fitted with electrically triggered quick release valves. The PPZ extinguishers use R-114B2, also known under the designation Halon 2402. It is very effective against any class of fire, but the tradeoff is that inhaling large quantities of it in a confined space (the inside of a tank, for example) is a huge health risk. It is advised to immediately throw open all hatches and exit the tank upon activation of the PPZ fire extinguishers. In the event of a penetrating hit, the tank and crew may be saved, but it cannot be manned until the gas has dispersed adequately. As such, the tank can be considered to be temporarily out of action.

Two handheld OU-2 carbon dioxide fire extinguishers are also provided to supplement the automatic fire extinguisher system. If the TD-1 fire detectors fail to respond (usually in the case of small flames), then these will be the only firefighting tools available to the crew, aside from manually activating the PPZ fire extinguishers via the driver's control box. Carbon dioxide fire extinguishers are suitable on Class B and C (fuel and electrical fires), so they are right at home inside a tank. CO2 fire extinguishers are also more directional that halon extinguishers, so the user can starve a fire of oxygen quite effectively within the confines of the tank. Using the OU-2 extinguishers might be a more appealing option to activating the 3ETs11-2 system, since your chances of asphyxiating is somewhat lower.

SELF ENTRENCHMENT

If a company of T-80s were to be called upon to defend a certain sector out of the blue, and there isn't any time to create proper fortifications, the crew may create their own cover using the dozer blade installed on the lower glacis.

On flat, dry terrain, it can take up to 20 minutes to dig a tank-sized dugout. For maximum stealthiness, camouflage netting and some improvisation is usually necessary for a proper disguise, but such preparations require more effort and time. 

However, because of the T-80's turbine engine, it is extremely ill-suited for static defence, seeing how the engine guzzles nearly as much fuel while the tank is immobile as when it is going at full speed. Because of this, it may not be able to sustain a counterattack when the moment comes. 

SMOKESCREEN

The secret to not getting blown up is to not get hit, and the secret to not getting hit is to not be seen. To that end, the T-80 is equipped with a smoke grenade system to shield it from prying eyes, but unlike prior Soviet tanks, the T-80 is unable to generate a fuel-based smokescreen from its engine, for fear of a potentially explosive result.  

902V Tucha

The "Tucha" smoke grenade dispersal system was universal between all Soviet armoured vehicles invented during the 70's, and was subsequently retrofitted to vehicles made before that. For some strange reason, the gunner - and not the commander - has access to the sole control panel for firing the grenades.

There are three variations of grenade layouts featured on the T-80 series. The T-80, T-80B and T-80U had their smoke grenades arranged on the front turret cheeks, which appears paradoxical: if the tank was hit in the front and the commander wishes to withdraw to a safer location, he may or may not be able to deploy a smoke screen owing to the damage received to the smoke grenade launchers. The damage may not necessarily have to be from a turret strike; a hit on the upper glacis with a HEAT round or an APDS round will invariably produce a large amount of secondary fragments, which will tend to be deflected into the turret face by the high slope of the upper glacis.

The T-80 and T-80B had a bank of five launcher tubes on the left hand side turret cheek, and only three launcher tubes on the right hand side due to the L-4 spotlight being in the way. Strangely enough, fewer smoke grenade launchers were provided compared to a T-72A without any good justification. The frontal part of the T-80B turret is virtually identical to the T-72A, and indeed, the left part of the turret has more than enough space to accommodate more smoke grenade launchers.

For the T-80BV, it was necessary to cluster the launcher tubes at the sides of the turret in order to not obstruct the placement of Kontakt-1 blocks over the turret cheeks. The earlier T-80BV with the T-80B turret and the late model T-80BV with the T-80U turret share the same configuration.

The launcher tubes on the T-80U are equally distributed, four per turret cheek. Since they are installed directly atop the Kontakt-5 panels, it's not hard to imagine what would happen to them if they got hit. Needless to say, many of the design decisions implemented on the T-80 series were highly suspect, to put it mildly.

NBC PROTECTION

Nuclear annihilation was a very real existential threat during the Cold War, and even more so during the 70's and early 80's; a period widely regarded as the peak of hostilities. Facilitating the crew's survival in the event of a nearby atomic blast or after one is the GO-17 NBC protection suite. The GO-17 system relied on a dosimeter installed inside the tank to detect and measure the dose rate of gamma radiation, and used a small air intake on the hull roof to detect the presence of biological or chemical contaminants in the air. The air intake was installed next to the driver's hatch, and is pictured below.

More details on the GO-17 NBC protection suite can be found on the T-72 article.

Under normal operating conditions, the crew was ventilated by a normal fan system with an integrated dust blower to ensure a clean supply of air. In case of NBC contamination, the system could operate on overpressure mode. The air intake for the crew compartment is located at the rear of the hull roof, next to the engine air intake. As you can see in the photo below, the air intake dome is protected from bullets by a heavy steel shield to the right.

The photo below shows the internal components of the ventilation system. The circular air outlet for normal, unfiltered air can be seen on the silver portion of the ventilator. The drum-shaped part is a filter designed to destroy biological and chemical particles contaminating the air. When the overpressure mode is activated, the circular air outlet is closed by a servomotor and the air is diverted into the drum filter.

Besides the more active part of the tank's anti-contamination system, the interior walls are lined with an anti-radiation material. The liner is composed of borated polyethylene - a type of high-density polyethylene infused with boron - woven into fibers and made into sheets, which are then laminated and bound by a resin. Boron is known to be extremely effective at capturing neutrons thanks to its large absorption cross section, making it suitable for use as radiation shielding. The fibrous construction of the sheets and the lamination process also makes it a suitable spall liner not dissimilar to early flak vests that used woven nylon plates.

MINE CLEARANCE

The mounting brackets on the upper glacis glacis are compatible with the KMT-6 mine plow. Th indiscriminately scoop up any mines, buried or unburied, anti-tank or anti-personnel, and shoves it to the side, creating a narrow mineless path for the tracks. This is fine... for the tank with the plow, which would be leading the crossing of the minefield as the only one of two in its company. For everyone else following behind, they can follow by driving on the track marks of the lead tank, but this is not possible in marshy and swampy ground, as doing so will lead to the tracks overpenetrating the soil, losing traction and getting stuck.

The ploughs can't reach anti-tank mines buried deeper than 8 or so inches, but this is fine, since the pressure exerted by the tracks probably won't be enough to set them off anymore at such depths.

DRIVER'S STATION

The left side of the cabin is dominated by the instrument panel. Just behind it is the front left hull fuel cell, and behind that is a stack of four accumulators.

On the right side of the driver's compartment, the hatch opening and closing mechanism is installed on the roof and behind it is the GO-27 gamma radiation detection unit system with its control board direction under it. The red boxes at the front of the hull are the fire location and warning indicator box (left) and fire extinguisher activation boxes (right), previously mentioned in the "Firefighting" section of this article.

Lighting for the driver is provided by a single dome light affixed to the ceiling of the station, just behind the driver's hatch and behind the driver's head, which is a rather poor idea since most of the light would be blocked by the driver, so finding the buttons on some of the control boards is harder than it should be. Just like the gunner and commander, the driver gets a DV-3 plastic fan right under his nose to help cool him down. The driver's seat is of the bucket type and is adjustable in height to allow him to drive under armour or with his head out of the hatch. The angle of the backrest can also be adjusted by a wide range of angles to ensure that the driver remains comfortable while performing his duties. The seat is shown in the drawing below

The driver is furnished with a GPK-59 gyrocompasss. It is particularly useful when driving underwater since there's no scenery to refer to. To use it underwater, the driver memorizes the figure indicated on the gyrocompasss dial while on land. This tells him about the orientation of the tank. Once the tank enters water, the driver can refer to how much the dial deflects whenever he steers left and right to know how much and how long he must steer in the opposite direction in order to reorient the tank back towards its original travelling direction.

The use of gyrocompasses can perhaps be labeled as a less sophisticated form of an Inertial Navigation System (INS), advanced versions of which are often present in modern combat vehicles due to their independence from outside input contrary to a GPS-based navigation system. You can see how the GPK-59 works on this video here.


The T-80 is speedy compared to most other tanks but unfortunately, the full potential of the powertrain is not exploited and the tank is not as nimble as it could be. While certainly able to turn fast, it isn't too graceful, and this can be blamed on the rather antiquated lever-type steering system. The steering levers have power assist and can be handled smoothly by an experienced driver, but it is not as easy to handle compared to contemporary German and American tanks that had long transitioned to motorcycle-style handlebars and steering wheel-type configurations.

As seen in the previous photos, the driver has a bank of three periscopes arranged in an arc to give a better panorama of where the tank is going, which, in the T-80's case, is sort of a mix between necessity and luxury. The relatively high cruising speed of the T-80 demands better-than-usual situation awareness on the driver's part as a safety measure, and compared with the earlier T-64 and T-72 with their single wide angle periscope, the T-80's three facilitates quicker turning as the driver can see the corners of the tank. There are two variants of the same basic periscope layout; the original version where the periscopes are largely exposed, and the modified version introduced on the T-80U where a protective roof was added above the periscopes. The roof has a high thickness of steel and its purpose appears to be to protect the periscopes from the blast and fragmentation of explosive munitions impacting the turret. It probably also helps keep rainwater from obscuring the periscopes too badly.

The visibility from these three periscopes is demonstrated in this video (link), taken by a T-80U driver.

At night, the driver suffers rather like all of his Soviet tanker brethren, only a bit worse. He is supplied with a single TNP IR imaging periscope. It facilitates a viewing distance of no less than 30 meters, within which he is guaranteed to be able to discern terrain features and obstacles, but because only the center periscope can be swapped out, the driver's field of view is rather narrow compared to the TNPO-160V used in the T-64 and T-72, which has a much wider aperture. With a view distance of only 30 meters and a bad case of tunnel vision at night, all the merits of the T-80's speed become irrelevant.

The driver is supplied with a face shield. It can be installed just behind the periscope, and it hooks up directly to the tank's electrical system. The face shield is mainly used when driving in convoys, serving to protect the driver's face from the dirt, insects and smoke (and in the T-80's case, hot exhaust plumes) of the leading tank as he drives with his head outside his hatch. It is only used when enemy contact is not a concern, as the shield prevents the cannon from depressing.

TRANSMISSION, SUSPENSION

The radically higher forces following the implementation of a gas turbine engine wore out the T-64's small diameter lightweight roadwheels and suspension at an alarming rate. Hence, the T-80 received an all-new reinforced torsion bar suspension system paired with larger and sturdier forged aluminium roadwheels with a diameter of 640 mm, and because of the much higher rolling speed of the tracks, it became necessary to have five return rollers instead of three (T-72) or four (T-64) in order to provide more dynamic support, and the RMSh tracks inherited from the T-64 required some modifications as well. Because of the extremely high spinning speed of the roadwheels, even the thick rubber rims were not enough to handle the stress, so the tracks needed to be outfitted with thick internal rubber pads which also helped reduce vibration when driving over uneven surfaces, and thus helped improve crew comfort and shooting accuracy when travelling at lower speeds.

The T-80 uses a hydraulically assisted mechanical transmission with dual planetary gearboxes and dual final drives. There are four forward gears and one reverse gear. The brakes are of a disk type, hydraulically operated. The T-80 turns on a pivot, meaning that to turn the tank on the spot, one of the two the tracks are locked in place while the other drives the tank around it. This system of neutral steering is mechanically simple, but vastly inferior to a pivot-type steering system where one of the tracks is run at the desired speed while the other is run slightly slower in the opposite direction. Besides being slower, false pivot steering creates a huge amount of friction and places more strain on the inactive track, leading to a quicker gradual weakening of the track and a shorter lifespan. To counteract this issue, the driver may "wiggle" the tank when turning so that the tension in the inactive track is released.

The transmission uses B-3V synthetic oil, of which 60 liters is needed. The same class of oil is used in helicopters like the Mi-17.

Because of the front-heaviness and high speed of the tank, nose diving into ditches and ruts would be particularly harsh on both the suspension and the crew. To alleviate the stresses of rough driving, the front two roadwheels and rearmost wheel are outfitted with hydropneumatic shock absorbers borrowed from the T-64. These aided recovery as the tank traversed natural obstacles.

The T-80 and T-80B have the same type of transmission. There are 5 forward gears and 1 reverse gear. The T-80U has a modified transmission with 4 forward gears and 1 reverse gear. Here's a video (link) of a T-80 driver showing off. The smooth transition to reverse and the high acceleration of the tank is demonstrated in the video. The T-80B weighs 42 tons. The T-80U weighs 46 tons. Stripped of additional armour, the T-80, T-80B and T-80U exert a ground pressure of 0.83 kg/sq.cm, 0.864 kg/sq.cm and 0.93 kg/sq.cm respectively.

ENGINES

With the sole exception of the T-80UD, the T-80 series featured a gas turbine engine. Contrary to popular belief, the T-80 was not the first tank in the world to mount this type of engine, only the first in the Soviet Union. The first serially produced tank to have a gas turbine engine was the Swedish Stridsvagn 103 which formally entered service in 1967 - almost a full decade before the T-80. However, the Strv 103 had a dual engine setup with an opposed piston engine supplementing its gas turbine engine, whereas the T-80 was propelled solely by a gas turbine engine. It was the first in the world to have this feature, followed shortly by the M1 Abrams which entered service four years later.

Unlike the T-64 and T-72, the gearbox of the T-80 was coupled to the engine together with the air intake system in a single powerpack assembly. It was the first Soviet tank to feature this, but it was by no means the first in the world. The photo below shows the powerpack of a T-80 with the GTD-1000T at its core. The large size of the air intakes is evident in this photo.

Compared to the T-72, the running gear of the T-80 is lighter by a small amount but it is still heavier than the running gear of the T-64 despite being a direct offshoot of the T-64A. The running gear of the T-80 weighed 8.28 tons, as opposed to the 8.47 tons of the T-72 and the 6.2 tons of the T-64. Although the T-80 uses a compact gas turbine engine, the weight of the engine is not less than the 5TDF of the T-64 and is even slightly heavier than the V-46 of the T-72, and besides that, the auxiliary systems accompanying the engine itself are heavier. For instance, large air intakes were necessary for the engine to develop its full power, and the large size of the intakes necessitated an engine compartment of larger volume.

The tracks and roadwheels of the T-80 are also heavier than the ones used for the T-64. As such, the tank weighed somewhat more than the T-64A despite having the same weight of armour and similar internal equipment, including the gun.

The turbine blades and turboshaft spins at 26,650 rpm, but the gearbox lowers this figure down to a maximum of 3,554 rpm on the seventh gear at the drive shaft. The final drives further reduce the rotational speed before the power is finally transferred to the drive sprockets.

It is well known that the biggest nemesis to any jet engine is the ingestion of foreign objects. The cyclone air cleaners built into the rear of the engine shoulder most of the burden of filtration but since they can only ensure an air purity of 98.5%, the engine will still ingest a small portion of pollutants, but contrary to popular belief, the dust consumption tolerance of gas turbine engines is reasonably high. To counteract the buildup of residue on the turbine blades, the designers implemented an ingenious solution whereby the blades would be shaken by high frequency vibrations produced by a system of motorized hammers. The hammers were tuned to vibrate the turbine blades at resonant frequencies, causing any particles on the surface of the blades to become dislodged and fall off. These particles are then blown out by blasts of compressed air. This purging process occurs during the startup procedure and during the deactivation procedure. This system is not dissimilar to ultrasonic polishing for jewelry, and the sum of all of the individual engineering solutions was so effective that the T-80U surpassed the T-90S in endurance during comparative endurance trials in India. The original T-80 performed exceptionally during its initial military tests as well, passing its hot climate trials in the Karakum desert in Turkmenistan with flying colours.

A portion of the engine's many essential life support systems can be accessed by simply opening up the engine compartment access hatch. Scheduled maintenance and regular check-ups can be done from outside, but to do any serious repairs on the engine or any of the drivetrain components, the entire powerpack often needs to be lifted out with a crane.

Th engine compartment cover has two filler ports for fuel and oil and two lifting points. The engine deck of a T-80B is shown in the drawing below.

There's no denying that the use of gas turbine engines in tanks have had more than their share of controversy, and for the most part, the controversy is not far off the mark. The most sanguine property is the excellent acceleration potential thanks to the high torque output of gas turbines at low revs, but the price for such performance is steep. From a defensive standpoint, the act of simply sitting idle to ambush or in wait of attack drains the tank's fuel reserves as prodigiously as when the tank is on the move, and if the tank were to be involved in a breakthrough assault as it was designed to do, the same issue limits its ability to exploit a successful breach and penetrate deep behind enemy lines.

Aside from that, one will find no small number of online sources repeating the claim that compact dimensions and low mass compared to conventional diesel powerplants are main selling points of this type of engine. The GTD series for the T-80 are no lighter than most diesel tank engines at a hefty 1050 kg (dry). However, it is a little smaller than many diesels, measuring in at 1.494 x 1.042 x 0.888 m (L-W-H) in all of its incarnations, compared to 1.480 x 0.896 x 0.902 m for the V-46 engine for the T-72. All members of the GTD family are marginally lighter than the AGT-1500, which weighs 1134 kg, and all of them are somewhat smaller, as the AGT-1500 measures 1.68x0.99x0.80.


An advantage to the use of jet fuels is that it will not gel up unless the ambient temperature is Arctic low, unlike raw diesel which will in fact gain viscosity in deep sub-zero temperatures if not mixed with some sort of antifreeze. The engines themselves can operate in ambient temperatures of down to -40°C and up to +40°C, but the true heat limit is significantly higher at +55°C, though running the engine at those sorts of conditions entails an extreme reduction of power. In addition to that, the GTD series of engines take no more than just 3 minutes to start up at temperatures of -40°C. That is more than 10 times shorter than the time it takes for a T-72 to get moving. This gives the T-80 a huge advantage in response time, which means that reinforcements can arrive around 40 minutes sooner, but the price of this blessing was very, very steep indeed. The price of the GTD-1000T was 10 times higher.

GTD-1000T

The GTD-1000T powered the original T-80. It would be later modified (minimally) to increase its output to match the ever increasing mass of future T-80 models. To the layman, the lower power output would ostensibly mean that the T-80 is less agile than something like the M1 Abrams (1980 original), but one must remember that the T-80 was nearly 36% lighter. The greatest bottleneck to the performance of the T-80 family was the manual transmission, which limited the acceleration of the tank in rough terrain and required more skilled drivers compared to a tank with an automatic transmission. The top speed of the tank on paved highways does not matter nearly as much, as the speed of tank convoys often depends on the optimum cruising speed (not top speed) of the tank where vibration and engine fatigue is minimal.



Power - 1000 hp (745 kW)
Rate of Rotation: 3554 RPM

GTD-1000TF

The newer GTD-1000TF for the advanced T-80B introduced in 1978 brought small but essential incremental improvements in both power output and fuel economy, which were achieved with the addition of a supercharger. Now, the engine is capable of developing 1100 hp, thanks to more oxygen fueling its fire, and the specific fuel consumption rate at full power was decreased slightly from 240 g/hph of the GTD-1000T to 235 g/hph (319 g/kWh). The GTD-1000TF is also used in the T-80BV. The photos below show the engine in the engine compartment of a T-80BV.

The photo below gives us a good view of location of the four accumulators, the oil and fuel tanks, and the air intakes (at the bottom corners of the photo). Note the little red TD-1 thermal sensor at the top left corner of the photo. Its location enables it to detect an electrical fire near the accumulators.

GTD-1250

To compensate for the added weight of Kontakt-5 armour on the new T-80U (1986), it was necessary to take another step forward and increase the power of the engine yet again. As its name suggests, the GTD-1250 can put out 1250 hp. The fuel efficiency of the GTD line-up reached its peak so far at 225 g/hph (306 g/hph).

Though still less economic from a design standpoint, the actual fuel consumption rate was nevertheless lower and the new engine gave the T-80U a small, but practically negligible edge in agility over the M1A1 and its descendants.

The GTD-1250 uses a modified exhaust port with an interrupted rectangular grille pattern instead of squares like on the GTD-1000T.


Net Power Output: 1250 hp

Max Torque Output: 4395 Nm

Rated Speed: 3,000 RPM



Supplementing the engine is the GTA-18 auxiliary power unit (APU). It is a small 30 hp generator outputting 18 kW. Only the command variants are equipped with an APU.

WATER OBSTACLES

For all the sacrifices that needed to be made to gain the extraordinary speed of the turbine engine, the ability to cross rivers was not one of them. The T-80 was equipped with the OPVT underwater driving system, containing the same elements as the T-72 but differing in the type of snorkeling equipment. The tank is able to cross a river with a depth of 5.0 meters with preparation and ford a stream with a depth of 1.8 meters with minor preparation.

Late model T-80 tanks may be provided with a proprietary "Brod" or "Brod-M" underwater driving system, allowing to drive into and across rivers as deep as 5.5 meters or even 12 meters in the case of the "Brod-M", and ford streams with a depth of up to 1.8 meters with minor preparations. Only the T-80UK and T-80UM models have this modification, and the T-80UD may have it as well. The snorkel configuration of the "Bord" kit is outwardly similar to the one used on the T-64, but the only real similarity is the implementation of a snorkel-mast where the commander can sit and direct the driver. However, the time needed to install the snorkels for the "Brod" system is much longer than for the OPVT system.

Photo Credit (Left): Maxim Volkonovsky

Ventilation for the crew is provided by the snorkel for both the "Brod" and "Brod-M" systems. For the "Brod-M", the large snorkel-mast is installed by locking it onto the commander's hatch. An internal ladder allows the commander to climb in and out of his station, and if necessary, the entire crew can escape a drowned tank through the snorkel. This is a safer way of escaping the tank as compared to the T-72 which had a simpler OPVT snorkel system that forced the crew to flood the tank by opening the hatches in order to leave. However, the

Photo Credit: Maxim Volkonovsky

The tank is provided with a snorkel adapter for the engine air intakes. The adapter is a simple, totally hollow shell made with thin sheet steel, encompassing both air intakes and curving to form a pill-shaped inlet duct. It is stowed in a special container mounted at the rear of the turret. Alternatively, it can be left attached to the air intakes for convenience, like in the picture below. In that case, though, the range of traverse of the turret is severely restricted.

The adapter also serves the secondary but equally important function of keeping the air intake grilles from being submerged or splashed with the water blown up by the exhaust. The clip below shows an early T-80 prototype using a pair of crude ventilation ducts as an interim solution.

While the pressure of the exhaust gasses is enough to eliminate backflow into the exhaust port in shallow water, it is not powerful enough to do so in deep water, making it impossible to use a valved exhaust cover like on the T-55, T-62 and T-72 for deep water driving. Instead, an exhaust tube is used to vent the exhaust gasses out and above water. Installing the exhaust tube requires the removal of the regular exhaust port, which can be hinged away and locked in place, as you can see in the photo below.

The exhaust port adapter is stowed away in a metal bin mounted on the rear of the turret.

Because of the large size and mass of all of the snorkeling equipment, it can take upwards of an hour to prepare for a river crossing. Fording a stream can be done without the crew ventilation tube and the exhaust tube, but the engine air intake snorkel must be installed, which can cost up to 20 minutes of the crew's time.

Crew members are each given a closed-circuit IP-5 rebreather for emergency use. It comprises a watertight, form fitting gas mask, a chemical respirator chamber containing potassium superoxide (KO₂), and a flotation collar. The rebreather uses the chemical reaction between potassium superoxide and carbon dioxide, activated by water from the user's breath reduce the former two to oxygen and potassium carbonate. The freshly produced oxygen gas is mixed into the previously exhaled breath to replenish its oxygen concentration for rebreathing. The crew usually puts the IP-5 on before entering water as a precautionary measure.

IP-5

ROAD ENDURANCE

In terms of fuel efficiency, the GTD-1000T was ostensibly unremarkable, guzzling jet fuel at the incredible rate of 240 g/hph (326 g/kWh), while its American cousin the AGT-1500 had a specific fuel consumption of just 213 g/hph (290 g/kWh) while simultaneously offering higher power. However, we must not forget to take the "hp" in g/hph into account. Multiplying 1000 hp with 240 g/hph yields 240,000 grams per hour, which translates to 192 liters of TS-1 per hour at full power. In real number terms, this is lower than the consumption rate of the AGT-1500 by 25%, while outputting 50% less power.

For an engine of about the same size and weight, this is perfectly reasonable performance. However, it is always necessary to strike a balance between striking speed and striking distance, and while the raw performance of the GTD-1000T may not be as optimal as desired, its dimensions and foundations enabled it to be easily uprated whenever the need arises. The best example of this is the GTD-1250, having a much higher power output of 1250 hp, while at the same time offering lower specific fuel consumption rates of 225 g/hph. In real number terms of efficiency, the GTD-1250 gave more power for every liter it took by 6.9% than the GTD-1000T, while the GTD-1000TF offered 2.3% better efficiency. The GTD series of gas turbine engines was not let down by poor Soviet engineering.


However, all of that is academic. Actual mileage testing has yielded some very interesting tangible results for the GTD-1000T engine. The engine consumes between 430 liters to 500 liters of standard TS-1 jet fuel for every 100 kilometers (62 miles) traveled on paved roads, or 450 liters to 790 liters for the same distance but on dirt roads, depending on the severity of the terrain. Assuming that the tank does not stop even once during its journey, the T-80 can travel between 233 kilometers to 409 kilometers on a full tank of fuel when driving cross country. The efficiency of a gas turbine engine will be lower for a smaller engine compared to a larger engine. This is one reason why the GTD series is less efficient than the AGT-1500.


This article is compulsory reading for all those meaning to understand the idiosyncrasies of gas turbine engines; strengths, weaknesses, and all. When operating with light loading, the power of the engine is not fully utilized. A large part of the fuel being consumed is burned up without doing any work, ending up as waste heat instead of useful mechanical energy. This is especially true for smaller engines like the GTD series. At full power, a gas turbine may be as efficient as, or more efficient than a diesel engine of the same power, but it is often not possible to travel place maximum load on the engine when travelling on most terrain. When idling, gas turbine engines are incredibly inefficient as they must guzzle fuel to compress enough air to feed its own fire.


Comparative testing of the T-80U against the Leopard 2A5 showed that the Leopard 2A5 could cruise around on gravelly mountain roads for a distance of 370 km, while the T-80U could go a similar distance of 350 km on the same track. As the Soviet doctrine of tank warfare involved a great deal of tactical maneuvering as opposed to static defence, it is conceivable that the constant motion of Soviet tank armies will result in a reduced rate of fuel wastage. However, it is clear that improved engine efficiency and the installation of an auxiliary power unit are still greatly desirable.

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The best tank in the Soviet Union was also arguably the best tank in the world for a good long while. This, however, had the unfortunate side effect of ballooning the cost of each T-80 to up to three times as much as its cousins. In fact, a single T-80 cost nearly as much as an M60A3! What a nightmare. Although more advanced by an appreciable margin, the usefulness to cost ratio for a T-80 was not favourable compared to a T-72 or a T-64.

With the fall of the Soviet Union and the subsequent economic collapse, the competition between the tank producing factories rose to a fever pitch. Today, only Uralvagonzavod remains. The Omsk factory in Saint Petersburg still refurbishes GTD gas turbine engines for T-80s still serving in the Russian Armed Forces, but no new examples are being produced. The production of the T-80 ended over a decade ago, and its fate has been sealed with the appearance of the T-90M and T-14.