The PT-76 amphibious tanks regularly served in our armed forces in various regions and were popular both with sailors and in the Ground Forces. In the well-established areas of the North and the Far East, these cars were often rescued as the only means of transport to the muddy road, on which it was possible to deliver food or take the woman to the nearest hospital. There were cases when they did not have time to get to the hospital, and courageous officer wives gave birth on the armor of “swimmers”.
PT-76 was used in hostilities in Africa, the Middle East, the Indo-Pakistan conflict 1965 of the year and was especially widespread in the 1965-1975 years in Vietnam by the North Vietnamese army. And, despite such a "respectable" age, these tanks are still in service with the Russian Army. PT-76 took part in the war in Chechnya.
In other countries, where the floating tanks were delivered, and there are more than two dozen of such countries only in foreign countries, these vehicles also continue to serve.
What explains such popularity and the birth of plans to modernize the floating long-liver? In my opinion, everything is very simple - since the adoption of the PT-76, nothing like this has been created that can replace this tank.
In addition, modern views of the theory and practice of warfare draw attention to the ever-increasing role of mobility of forces capable of conducting rapid, highly maneuverable actions on large spaces, both with a developed network of roads and on off-road operational areas, as well as conditions of severe destruction and flooding, artificial obstacles where a wide and fast maneuver is required by forces and means. In this regard, in the armies of many countries, to create mobile forces that meet these requirements. To equip such forces at the end of the 20th century, they began to develop and deploy production of a whole range of new light tanks, such as: Stingray and M8 (USA). CV90120 (Sweden) and others.
The formation of mobile forces today are in demand both in regular searches and in the composition of the internal troops (gendarmerie, police).
What are the requirements for a modern light tank?
First of all, light tanks should significantly exceed other vehicles of mobile forces in terms of firepower. Their weapons should be universal, ensuring effective defeat: open and sheltered, including in engineering structures, enemy manpower, anti-tank weapons of small, medium and long range, light in weight combat and special vehicles.
In addition, light tanks must be able to counteract heavy combat vehicles (medium and heavy tanks), destroying the latter or causing damage to them, causing their operation to cease during the battle.
It is also necessary that the armament of the light tank be able to protect mobile units from attacks by helicopters and low-flying aircraft in conditions of weak air defense.
The most important property of light tanks when operating as part of the mobile * forces is tactical and operational mobility. So, for example, the average speeds of movement of machines, consisting on the equipment of their forces. on the aggregate of road conditions must be at least 40-45 km / h with a reserve stock for fuel 500-600 km.
In the fulfillment of operational tasks, the design of light tanks should ensure the transfer of large masses of troops by road, rail, water, or air transport.
The most important property for light tanks is their amphibiousness, which allows troops to overcome water obstacles, such as lakes, rivers, canals, flooded areas, as well as act quickly in capturing and defending the coast or in a developed island zone.
It is fundamentally important that light tanks, in principle, cannot be replaced by others that are commensurate in mass, including infantry fighting vehicles (BMP), although such proposals have been heard more than once. This is due to the fact that tanks and infantry fighting vehicles are designed to perform various tasks, and the need to deploy troops with a limited internal volume of infantry fighting vehicles makes it impossible to deploy powerful enough tank weapons.
As a result of a comprehensive analysis of the development trends of light tanks, the most promising direction in the creation of a modern machine in Russia was the adoption of a profound modernization of the PT-76B light tank tanks that proved themselves well in service and in the battlefield.
Our Russian designers have developed a program for upgrading a floating tank. The lead company for the development of this program was the company Special Machinery and Metallurgy (Moscow). Its implementation allows not only to significantly increase the life of the machine, but also several times increases its combat effectiveness.
With regard to the previously listed fire tasks, the most versatile weapon for a light tank is currently a cannon. As such, for installation in the PT-76 tank, the Russian 57-mm automatic gun C-60 and 90-mm Belgian gun Mk III of the company "Cockeril" were considered. Preference was given to C-60. Below it becomes clear why. The 90-mm cannon has a great ability to combat bronzelelimi and at 1000-1500 m ranges the armor-piercing projectile has armor penetration in 1.7 - 1.9 times higher than the C-60 projectile. However, this is not enough to defeat modern tanks into frontal projections, and any modern tank takes to the board at the same ranges of the 57-mm gun.
Left view of the light modernized tank PT-76B
On the other hand, when firing an infantry combat vehicle (armored personnel carrier) at a distance of 2 km, the probability of hitting a target with one line of an 57-mm automatic cannon is 1,75 times higher than a single shot from an 90-mm Mk III cannon.
If we compare the results of firing from the same guns at the anti-tank missile system at a distance of 2,5 km, then the automatic gun surpasses the Belgian competitor 2 times. As for firing at helicopters, non-automatic guns are completely unable to fight such an opponent. At the same time, the automatic cannon in one turn hits this target with a probability of no less than 0,6. This is also important because mobile forces often operate in the absence of cover for highly effective air defense systems.
Considering the above, it was decided to drastically increase the firepower of the upgraded PT-76 by installing a new turret with an armament complex based on an automatic cannon mounted on the vehicle. The complex includes an 57-mm automatic gun (converted from the C-60 anti-aircraft gun). The revision of the gun and its loading mechanism with the aim of being able to be mounted on light armored vehicles was made by the Nizhny Novgorod Burevestnik design bureau. When firing an armor piercing tracer at a range of 1120, the gun provides penetration of 100 mm armor, in other words, it pierces the side of any modern tank. As for the reliable defeat of light-class armored vehicles, such as infantry fighting vehicles or armored personnel carriers, the new gun ensures their reliable defeat throughout the target range. Zabronevy action consists in breaking off and scattering fragments of the armored structure and the projectile as a result of the operation of the bottom fuse and the explosion of the projectile.
The 57-mm automatic cannon uses two types of regular unitary shots: with a fragment-tracer projectile and with an armor-piercing-tracer projectile. However, it is possible to use shots with a special anti-aircraft projectile (in this case, the maximum slant range for firing at air targets is more than 6 km.). Shooting from a cannon can be carried out by single shots, short bursts of 2-5 shots or continuous bursts. The maximum length of a continuous queue is 30 shots.
Automatics of the gun works at the expense of the shot energy, which makes it possible to dispense with the use of an external automatic drive, as is done on most foreign automatic guns. Automatics used in our company will provide an opportunity to obtain a design with acceptable weight and size characteristics and does not require additional power sources, and provides firing even in the absence of power supply.
To reduce gas content in the fighting compartment, the gun is closed with a protective casing with ventilation. The gun is equipped with an automatic loader and ejection of spent cartridges driven by sliding parts, which provides it with a technical rate of fire of 120 shots per minute. As an additional weapons in the new turret, an 7.62-mm PKT machine gun coupled with a cannon is used.
Combined sight "League-S"
Combat module of the upgraded tank PT-76B
Automatic ammunition on 20 shots.
The ammunition for the cannon is placed in an automatic 20 round of ammunition with a mechanism for selecting the type of ammunition in the shooting process and in a mechanized ammunition using 70 rounds.
Essentially automatic ammunition is an automatic loader with automatic selection of the type of ammunition. This device allowed the use of a single-threaded gun on the tank, while ensuring the use of ammunition of various types. The ammunition type change is carried out, automated in 2-4 seconds.
The replenishment of the automatic ammunition is carried out by the loader. It does not require any complex manipulations. The next projectile is selected from the mechanized ammunition and placed in the automatic. The total time for filling the automatic ammunition is two minutes. This design of the power supply system has no analogues in the world and can be considered as Russian “know-how”.
In order to ensure high accuracy of firing, a modern automated fire control system (SLA), working in conjunction with a new two-plane weapon stabilizer (STV), is included in the armament complex. MSA provides: round-the-clock target detection; measurement of the distance to them; defining and entering corrections for firing; stabilized targeting of primary and secondary weapons and the firing of ground, surface and air targets from a place, from a course and afloat with a selected type of ammunition with the required length of turn.
The sighting and observation complex of the control system includes a combined sight “Liga-S” with an independent line of sight stabilized in two planes (developed by one of the Belarusian optical-mechanical enterprises), having optical, infrared and laser rangefinder channels, as well as a duplicate of the main sight - zenith sight 1П67.
Correction for shooting is determined by a tank ballistic computer (TBV), working in conjunction with a set of automatic sensors for firing conditions. Such sensors in the OMS of the upgraded PT-76 tank are: League-S head mirror unit, laser rangefinder, heel, heading angle sensor, tank movement speed and weather conditions. Part of the data needed for making corrections for firing is entered into the TBV manually, such as air temperature and charge, barrel bore wear (total gun head), atmospheric pressure, and some others http://www.elconcept.ru/. In accordance with the manual firing conditions received from automatic sensors and manually entered in the TBV, the computer generates electrical signals corresponding to the aiming and leading angles that are fed to the control unit of the weapon stabilizer, and the PST guidance actuators aim the weapon at the pre-empted point.
The median error of stabilization when driving at a speed of 25 km / h is no more than 0,5 mrad. In other words, when shooting on the move with a specified speed of at least 50,% of hits when shooting at a range of 1000 meters will not deviate more than 50 cm from the aiming point.
To improve the visibility of the vehicle at the workplace of the tank commander and loader, prism observation devices were installed: four TH PO-170A and two TN PT-1.
Based on the firing from the spot, on the move, afloat, the following average data characterizing the effective firing range of the 57-mm automatic cannon of the upgraded PT-76 at various targets was obtained:
for medium and main tanks (defeat after penetration of onboard projections) - up to 1000 m:
on infantry fighting vehicles (armored personnel carriers, self-propelled guns) - up to 2100 m:
towed artillery - up to 2300 m;
for unarmored vehicles - up to 2500 m;
on manpower in defenses - up to 1300 m;
on open manpower - up to 3500 m;
by helicopter - to 4000 m.
Elements of the stabilizer weapons upgraded tank PT-76B
1 - control panel
2 - control unit
3 - Gyrotachometer
4 - Inverter
5 - amplifier
6 - drive motor
7 - gun position sensor
8 - angle limiter
In general, the new weapon system provides the upgraded vehicle with increased firepower compared to PT-76B by 5.5!
At the same time, there are real technical possibilities for the implementation of other options for constructing an SLA - from less complex to the most modern, using a thermal sight. The use of guided missile weapons and the inclusion of an appropriate control channel in the LMS are also not excluded.
Along with the task of achieving a new level of firepower with the modernization of the tank, the task of increasing the mobility and reliability of the machine was solved. This provides for the full restoration of the resource tank.
In order to increase the mobility of the vehicle on land (afloat in its class, tanks of the PT-76 type are still unequal), a more powerful UTD-23 diesel engine (hp 300 power .c.) and transmissions used on BMD-238, with appropriate supporting systems.
Gearbox installed when upgrading the tank PT-76B
This allowed significantly, from 17.1 at least to 20 hp / t, to raise the specific power of the tank. According to this indicator, among the light tanks, the upgraded vehicle is second only to the newest US light tanks, Stingray and M8.
However, it should be noted that American cars are not capable of swimming across water obstacles, which greatly limits their maneuverability and reduces the value as a light tank. The Russian modernized PT-76 kept its buoyancy at the same level.
Mobility upgrades: the tank allowed the maximum speed to be increased from 44 to 60 km / h, and the average speed on pound roads from 32 to 42 km / h.
Installed on the machine and new tracks with the best grip and long service life. Modernization of the power plant on the chassis developed by the Volgograd Tractor Plant design bureau, mobility, it allows to increase the operational reliability of the machine, and reduces the fatigue of the driver when making long marches and driving difficult terrain conditions.
The incompatibility of the requirements of high mobility, buoyancy, air mobility and armor protection from the effects of anti-tank weapons made limited the ability of the PT-76 design to protect the crew and internal equipment of the machine from heavy machine guns, small-caliber automatic guns, artillery shrapnel and mines. Moreover, practically any armored design of a combat vehicle weighing up to 30 t does not provide protection against the shells of tank guns and grenades of hand-held anti-tank grenade launchers.
General view of the light modernized tank PT-76B
The security of the upgraded machine and its survival on the battlefield are provided with a new high-speed fire extinguishing system. In addition, the equipment is considered to be equipped with a system for scanning and detecting optical devices (like sniper detection instruments) and automatic target designation. In other words, as soon as an optical device appears in the field of view of the sight, aimed at the side of the tank. The LMS in automatic mode will split the turret in a fraction of a second in its direction, prepare the data for firing and hover the gun at it, all that remains is to press the firing button.
A promising solution is to equip the upgraded tank with a system of mounted dynamic protection, allowing the machine to be protected from hand grenades and anti-tank grenade launchers and anti-tank guided missiles with tandem combat units. And such systems in Russia have already been developed and tested.
Another direction to enhance the protection of the upgraded PT-76 (and other light combat vehicles is the system of opto-electronic suppression of the control channels of anti-tank missiles and corrected artillery shells and mines in the final section of the trajectory, as well as active protection complexes. Such systems have also been developed and tested. By the way, American specialists show great interest in them, having the goal to minimize the loss of their armored vehicles in Iraq. In general, light tanks can be provided reliable protection from the effects of most anti-tank weapons, it all depends on the thickness .... No, not armor, but the customer’s wallet.
One of the important properties of modern armored vehicles is command control. In this regard, the modernization program PT-76 replacement of previously installed communications with modern ones. At the request of the customer can also be installed and means of communication of foreign origin.
The process of upgrading the PT-76 is technologically advanced and requires a relatively low labor intensity. This is achieved through the use of modular technology.
In the course of modernization, two major technological operations are being carried out on the installation of a new combat module and the installation of a new engine with improved transmission assemblies. These operations can be carried out at enterprises with a minimum of high-tech equipment, including forces of military repair enterprises. By the way, after the development of the described modernization program for the PT-76 tanks, it was decided to resume the production of spare parts for this tank at the main manufacturer.
Modernization of the PT-76 tank according to the considered project will increase its combat capabilities by 2.7 times, which, at relatively insignificant costs, takes this vehicle to the level of a new modern light amphibious tank that meets all the requirements for this class of combat vehicles. Great for you swimming good old "floater"!