Armor protection of the tanks of the second postwar generation T-64 (T-64A), Chieftain Mk5P and M60
© Andrei Tarasenko
Technical data on soviet 1-st post WW2 generation of tanks, Like T-54, T-55 and T-62 are well known and well described in literature. But what if Soviet “premium” tanks of 70-s era were engaged into real combat against western tanks in Europre.
This article provides
description of "Object 432" (T-64) and T-64A tank combined protection
(composite armor, anti radiation and chemical protection) in comparison to
western designed tanks – “Chieftain” Mk5P and M60A1. Information on T-64
protection includes technical project (presentation) dated 1961 and technical
drawings from various periods. Information on “Chieftain” Mk5P and M60A1 tanks is a result of study of captured tanks
T-64 was the first tank with complex combined protection. When designing the T-64 tank, designers paid equal attention to the issues of protection firepower and mobility. For its time, the "Object 432" (T-64) tank had the most powerful armor protection not only among Soviet tanks. No medium or heavy tank in the world could match T-64 the level of protection, including the British “Chieftain” tank, which was considered by some researchers as the one of most heavily protected Western block tank.
Also much attention was paid to the issue of protecting the crew from the penetrating radiation of an atomic explosion, which was one of the important requirements for the Soviet designers at that time.
The war to which the Soviet’s were preparing meant the widespread use of tactical nuclear weapons, the same was expected from opponents.
The complex combined protection of the "Object 432" consisted of:
• armored steel, which main purpose was protection against armor-piercing sub-caliber projectiles;
• anti shaped charge materials of large thicknesses, which are significantly inferior in strength to steel, which means that they are much lighter;
• special anti-radiation materials, providing, in combination with the rest of the elements, biological protection.
Technical requirements for "Object 432" armor protection level against armor piercing projectiles. Chief designers notes are visible on the paper,
"Object 432" hull and turret armor protection
Like all pioneers, the designers of the T-64, led by Alexander Morozov, had to face many difficulties in solving the task of equipping the tank with composite armor, an important role in the solution of which was played by VNII-100. Not all initial decisions proved to be correct, but there was no previous experience in design of composite armor in anywhere at that time.
In the initial technical project of the tank "Object 432" presented in 1961  two versions of the filler were considered:
Cast turret with “ultraporcelain” inserts with the initial base
thickness equal to
Turret with “ultraporcelain” (ceramic) inserts.
Protection was provided in 70° frontal arc
Cast turret, consisting of a steel armor base with cavities, an aluminum
anti-cumulative inserts were filled into turret cavities after casting a steel
base. The total maximum LOS thickness was ~ 500-
"Object 432" turret with aluminum filler with LOS numbers of LOS thickness
Both versions of the towers gave more than one ton of weight saving compared to a homogeneous steel turret of equal protection. Due to delays in manufacture of “ultraporcelain”
ceramics and initial quality concerns an aluminum filler was chosen for the serial production of "Object 432" medium tank, which received T-64 designation.
About 1300 (1285) T-64 tanks were produced (1964-1969) and served in
Soviet army up to the 1990-s when they were mostly scrapped according to arms
limitations treaty in
During the accumulation of experience, a number of drawbacks of the turret were revealed, primarily related to its large dimensions of the thickness of the frontal areas which cramped tanks interior.
In 1967-1970 period a new the design of modernized T-64A turret with
high hardness steel plates inserts was in production. Finally in 1971 initiall
design with “ultraporcelain” was mastered and balls inserts were used up to the
end of serial manufacture of T-64A and its modifications in 1987 (turret LOS –
Historical 1976 documentary about
T-64A manufacture on Malyshev Plant in
T-64 front hull protection was also new for tank design. The front hull
had composite protection consisting of
"Object 432" from 1961 technical project presentation with 80 steel + 140 glass fiber front hull
Driver’s sights placement and front hull of the "Object 432"
The upper sides of the hull were made of
First variant of T-64 "Object 432" front hull design
First variant of T-64 "Object 432" used for target practice in 90-s
The use of fiberglass, also provided a reliable (with exceeded technical requirements) antiradiation protection. The absence in the technical design experience resulted in not ideal solution. Lack of back plate evidently decreased frontal hull survivability. The upper sides of the hull - "cheekbones" were also more vulnerable to shaped charge attacks.
The lack of back plate after the glass fiber layer shows a complicated search for the right technical solutions for creating the optimal three-layer armor.
T-64A "Object 434" drawing with “classical” 80 steel + 105 glass fiber + 20 steel front hull
After the solution of initial frontal hull design problems "Object 432" and all later produced variations, including T-72 and T-80 used same three-layer armor for a next decade.
Finally at the beginning of 70-s composite armor of soviet tanks provided
reliable protection against shaped charge projectiles equivalent to
The overall increase of weight of the tank over T-62 was only 2 metric tons.
It should be noted that the layout of the driver compartment provides additional protection for the driver on the left and right by the front group of fuel tanks, which is produced last, and the left 4 battery packs. To further protect the sides of the hull from cumulative short-range weapons, flap-mounted aluminum anti shaped charge shields were installed on the sides of the tank, later replaced with solid rubber-metallic screens.
Explosive reactive armor
Soviet designers were pioneers not only in composite armor, but in the area of explosive reactive armor, locally known as dynamic armor.
The idea of reactive armor appeared on the basis of WW2 experience, first materials were published in 1946, following laboratory tests in 1949. Full scale testing of experimental hulls with ERA using 115-mm APFSDS and various shaped charge warhead commenced in 1968 with good results. The success of testing allowed recommending a new design of the hull front for installation on T-64A tank. But due to reasons not clear for now this works did not realized in production. It can be assumed that the existing armor protection level of T-64A tanks was adequate to the treats of 70-s. Another reason was a strong opposition of certain high rank military officials to the installation of explosives on tank external surfaces.
Results of fire trials of
T-64 reactive armor designed in 1968
Installation of new ERA on T-64A tank could provide increase of
protection against shaped charge projectiles at the level of
Protection from weapons of mass destruction
In addition to composite armor, the key attention was paid to protection from the weapon of mass destruction. To protect the crew from penetrating radiation in the area where the crew workplaces were located and where the thickness of the armor protection was insufficient, a special anti-radiation lining and appliqué was installed. In addition, this lining provided some additional level of protection from splinters, breaking off from the armor during the shell impact.
On the T-64, an automatic collective defense system against WMD and chemical weapons system was installed. A powerful filter-ventilation unit provided overpressure inside the tank, which excludes the immission of contaminated air inside the tank. Therefore, the crew could overcome the contaminated areas without special protective equipment.
Biological protection of driver
The biological protection of the hull was determined by the protection of
the driver, which, for better visibility, is located along the longitudinal
axis of the tank, which made it possible to implement its local anti radiation
protection. The main element of this protection was the
Biological protection of turret crew
Large arrays of armor in the front part of the turret allowed to use
thin 20 to
The roof of the tower is equipped with a rebound of
Overall protection against penetrating radiation from a nuclear explosion of an average caliber (30 KT) was decreased 15 times.
Protection of turret with anti radiation lining
Fuel tanks also provided protection to the driver from sides
This ensured the safe location of the crew in a tank at a distance of
The protection also provides 18-time decrease of radiation in the contaminated area, which allowed the crew to be in the area of radioactive contamination at a level of 300 roentgen per hour for 12 hours, at an admissible dose of 200 roentgens.
Protection from incendiary weapon
Attention was also paid to the protection from incendiary weapon such as napalm, widely used in the West. First of all it concerned rollers of the tank. The tank's rollers had internal cushioning. The main part of the rubber was covered with an aluminum cap. Thus, the tank could cross the fire zone without threat of being left without rubber bandages.
The use of an ejection cooling system with a sealed box under the roof of the motor compartament reliably protected the engine and transmission assemblies from the penetration of incendiary mixtures.
Comparison of armor protection of T-64 with the "Chiftein" Mk5P
In the early 1980s, the
Results of study
The design of the "Chieftain" is made in accordance with the
concept adopted in
The same marks of steel armor were used for hull and the turret protection, which were used earlier for the “Centurion” tank.
Both tanks have large dimensions and weight. The weight of the "Chieftain" Mk5P is 54.8 tons. The weight of the hull and the turret armor is 29 tons, which is 53% of the total mass of the tank.
The hull is made welded using homogeneous cast and rolled armor of medium hardness. The cast upper hull detail has a complex streamlined geometric shape.
The lower frontal part is made of rolled armor
In the aft part of the over tracks shelves in the zone of the motor-transmission
compartment there are compartments in which the rubber-fabric fuel tanks are
placed. The walls of the compartments are made of rolled steel armor with a
Along hull entire length on both sides of the tank at a distance of
Let’s examine the geometric scheme of armor protection (figure).
Scheme for armor protection
of the “Chieftain” Mk5P tank on the basis of a study of the sample received by
Analyzing the tank protection scheme (see the figure) together with the
data (table below) it can be concluded that the tank has no anti shaped charge
protection of hull and turret, since the horizontal thicknesses of homogenous
armor do not exceed
However, it should be noted that a four-section aluminum side-screen
with a thickness of
It turned out that the protection level of frontal projection of turret
and hull provides protection from the
All types of shaped charge rounds (HEAT) can penetrate "Chieftain Mk5P" at all realistic ranges of fire.
Protection of the upper frontal part of the hull and the frontal part of the turret provides protection:
from 100-mm caliber and armor-piercing sub-caliber shells of the T-54/55
tank at a distance of
from 115-mm APFSDS of the T-62 and T-64 tank at a range of
protection from 125-mm APFSDS of T-64A (T-72, T-80)tanks is not provided.
The tank can be penetrated by these projectiles from a distance of more than
The rest of the projections of the hull and the turret have a low level of protection. Rear parts of the hull and turret has anti-bullet and anti-fragmentation protection. The welded joints of the hull and tower parts are made with the use of mechanical processing of the edges and have small legs of welded joints made without a complete fusion. Such a design of welded joints has a low survivability in firing by armor-piercing sub-caliber and high-explosive fragmentation projectiles.
Characteristics of sub-caliber projectiles for the D-81 gun
Features of the “Chieftain” Mk5P turret are:
a narrow embrasure with a width of
the fastening of the cannon (trunnion) in the tide protruding in the frontal part of the tower, which significantly reduces the weakened zone of the frontal projection of the tower;
the presence of compartments outside of main armor of the fighting compartment in the aft part of the turret, in which additional equipment is located.
Distance D and velocity V of penetration
* Considered with hull and the turret safe maneuvering zones for the hull ± 20 °, and for the turret ± 35 °;
** including the casing of the support rollers to the body;
** at nominal speed.
In the early 1970s, the
The armored design of the American M-60A1 tank and its subsequent modifications is different in that both the body and the tower are made of a homogeneous cast steel of a transverse thickness.
The hull is made of solid cast steel with welded bottom. The cast part
of the bottom has a thickness of
The sides of the hull have a complex configuration, which allows to
arrange individual parts at constructible angles of inclination up to 50° from
the vertical axis. The thickness of the side variable - from 40 to
The upper front hull detail has the same thickness (
The front roof of the hull has a thickness of
The turret of the tank is a cast with variable thickness with different
structural angles in height and contour and with a characteristic elongated aft
niche. The frontal sections have a thickness of 180-
The sides of the turret are not symmetrical: the left side is 85-
The front roof of the turret has a thickness of
Turret back has a thickness of
The armored protection of the M-60A1 tank is highly differentiated. The use of cast armor made it possible to use a variable thickness in the lower frontal hull, on the sides and rear of the hull, and also on the turret - along the height and along the contour.
The frontal projections of the tank are protected from its own 105-mm
gun projectiles from the real battle distances: the upper front sheet of the
hull is from a distance of
From the armor-piercing 100, 122 and
Turret - at the course angles of firing ± 30 ° - from a distance of more
Upper front hull detail - when firing at point-blank with a
Protection of the turret at a course angle of firing 0 ° is ensured at a
relatively small thickness, mainly due to large angles of slew – 55-60 °. At
the course angles of firing ± 30 ° the protection of the turret decreases very
sharply and it can be penetrated by armor-piercing-subcaliber projectiles from
a distance of more than
The upper front hull detail is protected due to the thickness of the steel plate and a large structural angle of 64 °. The level of protection of the lower frontal sheet of the body is somewhat lower than that of the upper one, but its protection is much higher than that of existing serial tanks.
Scheme of armor protection of the tank M60A1 
* - The positions in the figure are indicated in parentheses
** - turret front angles of slew 55 - 60 °
The sides of the hull provide protection against a
The developed rear part of turret increases the internal volume and gives turret a prolongated form, which determines the significant overlapping of the turret rear of the engine-transmission compartment and the appearance of "shot trap" of large dimensions.
This can lead to a significant weakening of protection from high-explosive fragmentation and armor-piercing fusible projectiles. M-60A1 tank is not protected from the existing cumulative rounds at any range.]
Unlike the West German tank "Leopard-1 A4" and the English "Chieftain", there are no even anti-cumulative screens along the sides of the hull.
A cast cradle mask attached to the gun barrel creates an additional
protection for the turret at the weakened point of under the embrasure, but
this zone is still a weakened place. Mask-cradle can protect only from
splinters and bullets. A weakened place of protection is also the zone of the
joint between the tower and the hull, where the possibility of flying fragments
can cause the tower to get stuck. A significant weakening of armor protection
is created by the commander's turret, protected only from a
The scheme of weakened zones of armored protection of the tank M-60A1
1 - the joint of the hull and tower, 2 - the commander's turret, 3 - the cannon's embrasure, 4 - the blinds, 5 - the hatches, 6 - the embrasure of the range finder, 7 - driver's viewing devices
Comparison of side and frontal projection of T-64 and M60 tanks
Relatively large area of the frontal projection (in
comparison with other foreign tanks) indirectly weakens the defense, increasing
the probability of hitting the tank. This was specially important criteria in
the times when most tanks had no laser rangefinder systems (1960-1970-s). An
internal volume of the tank M-60A1 (
The weight of the tank "Chiften" Mk5R is 54.8 tons. The weight of the protection is 29 tons, which is 53% of the total tank weight.
At the course angles of firing ± 30-35° the protection of the turret
decreases very sharply and it can be penetrated by armor-piercing-subcaliber
The weight of the reservation M60A1 is 27 tons with a weight of 49.6 tons.
Soviet approach to armor protection required ± 35° area of safe maneuvering zone for turret, which largely exceeds the parameters for both "Chieftain" and M60A1.
Protection against WMD of T-64 tanks also much superior to western tanks of that time.
Despite the fact that the "Chieftain" has a large overall mass, its armor protection does not exceed M60A1, but is inferior to it in some aspects.
Also this article concerns only protection against armor-piercing-subcaliber projectiles, as both western tanks can be easily penetrated by all existing HEAT rounds of 60-70 period at any ranges.
It is worth noting that despite the conservative design approach for the
"Chieftain" does not cancel British innovative approach to tanks
design in general. Since the second half of the 60-s the development of a new
type of armor, called "
Judging from now uncovered reports available in British archives western designers were not aware of a fact, that T-64 tank (and it’s modifications) had composite armor.
It is evident from 1978 report «Technical Assessment of the Soviet T-64 medium tank».
Page from the report «A Technical Assessment of the Soviet T-64 medium tank»
Starting from the first half of the 1980s, this type of armor will be installed on NATO and US tanks, providing them with high rates of anti-cumulative resistance and protection against APFSDS.
Almost in that period of time in
Overall in 60-s ERA Soviets were definitely leaders in armor protection, this situation shifted in the beginning of 80-s. But this is a theme fore another research.
1. Medium tank “Object
2. Questions of defense technology. - 1983. - No. 5 (111)
3. Questions of defense technology. - 1967. - Issue 67
4. Armored forces herald. - 1980. - No. 4