Constructive vulnerabilities of the main combat vehicle AOI "Merkava Mk.4"
Decision to develop your own tank It was adopted by Israel in 1970 after the refusal of the United Kingdom to sell tanks "Chieftain." Former tank commander of the AOI, retired Major General Yisrael Tal, author of the Israeli military doctrine on the use of armored forces, was appointed head of the development of the new tank.
The design of the tank was named Merkava - the chariot.
The development leader made a decision in principle to abandon the classic tank layout, which had previously been developed within the framework of the Soviet, American, German and British tank design schools. Being a professional tanker, I.Tal did not focus on the protection of the machine, but on the protection of her crew. To this end, he placed the engine compartment (MTO) in the nose of the case and applied a front-wheel drive tracked propulsive. The front fuel tanks located behind the lower frontal part of the hull, the armored partition between the tanks and the logistics, as well as the armor partition between the logistics and control compartment are used as additional protection for the crew.
The second fundamental difference between the "Merkava" and classic tanks was a significant increase in hull height (up to 1860 mm) while reducing the height of the turret. In making this decision, I.Tal was guided by the combat statistics of hit in tanks at the beginning of 1970 - more than half of the projectile strikes were in the projection of the tower.
As part of the tank was originally supposed to apply enhanced booking, which led to an increase in the bearing surface of the tracks by increasing their width and length. The first modification was protected by homogeneous armor, subsequent modifications increased the protection through the use of overhead modules of composite armor and side screens. In connection with the use of multi-layered armor with air gaps between the layers, the installation of elements of dynamic protection was impossible.
The tall hull allowed the engine and transmission to be linked in height, freeing up additional volume in the stern of the relatively long hull of the tank. As conceived by the main developer, this section was to be used to transport the reserve crew of the tank.
In order to implement this controversial decision, the tower shoulder strap was located in the classical style - in the center of the hull, which did not allow the weight of the tower to balance the weight of the engine with the transmission. As a result, the Merkava center of gravity shifted forward, which was reflected in the uneven placement of the track rollers in the longitudinal plane.
The armament of the first modification of the tank consisted of a 105-mm rifled unitary loading gun, two 7,62-mm machine guns (one of which was paired with a gun, the other was mounted on a turret), an 60-mm mortar installed inside the control compartment and firing fragmentation and lighting mines, and smoke mortars fixed outside the tower. In the aft niche of the turret there was a mechanized ammunition on 5 shots, increasing the rate of fire from the gun within the specified stock.
For the first time in tank building practice, all shots to a tank gun, cartons with cartridges and mines were in fiberglass refractory containers that withstand open flame for 45 minutes. In addition to this, the logistics, control and additional departments were equipped with a powerful fire extinguishing system. Aft fuel tanks were removed from the hull to separate lightly armored tanks.
Also for the first time in the practice of tank building in the serial tracked vehicle, the suspension rollers of the Christie rollers with an external arrangement of dual springs and tubular shock absorbers were used. This solution made it possible to double (up to 604 mm) the full travel of road wheels as compared to tanks equipped with a torsion bar suspension and to significantly expand the free volume of the hull. One half of the balancers of the road wheels were turned towards the nose, the other half towards the stern of the hull.
A modification of the Merkava Mk.1 tank was adopted by the Israel Defense Forces in October 1979. The first combat test tank passed in 1982 year during the First Lebanon War. The results of its combat use were ambiguous - on the one hand, the Merkava suffered small losses (up to 15 machines, of which 7 was irrevocable), on the other hand all the lost tanks were hit by ATGMs, since during the war there was not a single fire contact with the Syrian Soviet-made T-72 tanks.
The Merkav debut on the battlefield was badly damaged by the photo frames of one of the cars burnt by the ATGM at the Beirut airport. Due to the fact that these pictures went around all the major newspapers in the world and in order to rehabilitate the design of the newest Israeli tank, the Merkava staged firing at the T-72 Syrian tank, previously hit by the Tou ATGM and located in the neutral zone, was organized. The shooting was carried out after the conclusion of a truce between the warring parties under the cameras in the presence of the Chief of Staff of the IDF.
In subsequent years, the Merkava participated in all local military conflicts in southern Lebanon, as well as in police operations in the West Bank and the Gaza Strip. In connection with the constant increase in the combat capabilities of the enemy’s anti-tank weapons, the Merkava tank was upgraded by increasing the caliber of the cannon and installing a modern fire control system, enhancing armor protection in the form of mounted composite armor modules and onboard screens, as well as increasing engine power due to an increase in tank mass.
The chassis of the “Merkava” has also undergone significant changes - the balancers of all road wheels were turned to the stern, the openly located tubular shock absorbers were replaced with blade-type, mounted in the thickness of the armor.
The latest version of the Merkava Mk.4, put into service in the 2004 year, weighs 70 tons, is equipped with a hp 1500 diesel engine, a five-speed automatic transmission and a 120-mm smooth-bore gun. The capacity of the mechanized ammo pack is increased to 10 shots. Suspended composite armor mounted on the sides and on the roof of the tower, as well as on the upper frontal hull details. The sides are protected by multi-layered screens, the bottom is a steel sheet installed with an air gap (with a decrease in clearance from 530 to 430 mm).
However, these measures led to the opposite result. While in the First Lebanese War 1982, the Merkava Mk.1 was used as the main battle tank (MBT) with a small level of losses, while in the Second Lebanon War 2007, the Merkava Mk.4 suffered a loss in approximately 50 machines (half of those who took part in the operation in the territory of South Lebanon), of which 10 were irretrievably destroyed.
As a result of the opposition from the Lebanese organization’s Hezbollah militia units, which rely on pre-prepared fortified areas (located in populated areas) and armed Soviet-made RPGs and anti-tank guided missiles with tandem shaped charges, the IDF command was forced to remove Merkava from the assault groups and take them to the second tier.
From this point on, the Merkava began to use self-propelled artillery systems for firing at the front edge of the defenders, since the magnitude of the tank gun and the gunners' qualifications did not allow them to mount fire on targets in the depths of urban areas of fortified areas. Left without a tank cover, the infantry of the assault groups suffered substantial losses.
The plan for the military company was thwarted — the IDF ground attack in southern Lebanon was stopped, Hezbollah’s rocket attacks on Israel increased throughout the Second Lebanon War and were stopped only after a truce between the opposing sides.
The main reason for the IDF’s refusal to use the Merkava as an MBT was the design vulnerabilities inherent in the very first modification of the car.
I.Tal, being the main ideologue of the original Merkava layout, made a fundamental mistake - he replaced the concept of tank protection with the concept of crew protection. At the same time, the method of protecting the crew was also chosen incorrectly - due to the substitution of a vital component of the tank structure - an engine block with a transmission. Thereby, one of the mandatory requirements for the OBT was ignored - countering the loss of travel.
At the same time, the protection of the hull forehead increased by less than 10 percent: the thickness of the upper frontal part together with the composite armor is 200 mm at an angle of 75 degrees, the thickness of the vertical partition between the nasal fuel tanks and MTO - 40 mm, the thickness of the vertical partition between the MTO and the control section - 80 mm, additional protection from the engine and transmission is estimated to 60 mm steel homogeneous armor.
But the situation with the protection of the Merkava from loss of stroke is even worse - the lower frontal part of a high body with a thickness of only 100 mm at an angle of 25 degrees cannot save the MTO from being hit by rocket-propelled grenades with RPG-29 type charges - the precharge pierces the lower frontal part , the main charge pierces the 40-mm septum and disables the engine with the transmission, simultaneously burning the fuel in the nose tanks.
In addition, the use of a front-drive tracked propulsor forces the drive gears into the nose of the hull into protruding niches. Even being covered with armor of a certain thickness, the gear mechanisms of the gearboxes and bearings, on which the axles of the driving wheels rest, are extremely sensitive to any distortion of their design. Therefore, an explosion on the lower frontal part, on a caterpillar or on the ground under the 152-155 mm tank of a high-explosive fragmentation projectile or a thermobaric grenade fired from an Hashim RPG, will also lead to loss of travel without breaking through the frontal armor.
Paradoxically, but the fact is that if the Merkava MTO were moved to the place of an additional aft compartment, and the built-in fuel tanks were placed in the treadmill sponsons, the empty volume in the nose could be filled with a composite cake of thickness 1500 mm, and all this without the risk of loss of travel in the case of partial penetration of armor protection or jamming of the onboard gearboxes.
The developers of the first modification of the tank made two more engineering mistakes: - they increased the height of the hull and placed the towing tower in the center of the hull.
The first mistake led to a sharp increase in zarvievogo volume. As a result, the 70-tonne Merkava Mk.4 has a 1,42 times less security (3,18 tons / cubic meter) than the 50-tonnes T-90MS (4,54 tons / cubic meter). It should be borne in mind that due to the massive introduction of the LMS, the combat statistics of the hitting of shells into the tank in 2000-ies has changed dramatically - now most of the strikes are in the hull, not the tower.
The second error led to a shift in the nose of the center of gravity of the machine. This causes a swing of the tank hull when firing on the move, negating the technical rate of fire of the gun provided by the semi-automatic loading mechanism.
A direct consequence of the original Merkava layout is also the degraded accuracy of aiming the cannon at the target when firing forward in the range of horizontal pointing angles + -15 degrees while the engine is running. The flow of warm air rising from the upper frontal part covering the heated engine causes distortion of the visibility of the target in a tank sight. Therefore, the main way of firing the Merkava with a running engine is to turn the gun sideways at an angle of more than 15 degrees, recorded in numerous photo and video frames. At the same time, the tank automatically substitutes its weakly protected board under attack of the enemy.
After the Second Lebanon War, the AOI attempted to upgrade the tank once again by installing a Trophy active defense system designed to intercept rocket-propelled grenades and anti-tank missiles. 1 March 2011 year-ready attack elements, fired from a mortar, for the first time in a combat situation on the border with the Gaza Strip struck a rocket grenade fired at the Merkava.
But the Trophy has a fatal drawback - the radars for detecting rocket-propelled grenades and anti-tank missiles are openly mounted on the tank turret and absolutely vulnerable to small-arms bullets weapons, not to mention the shrapnel and small-caliber shells. Therefore, in future clashes, IDF opponents armed with RPGs and anti-tank guided missiles will likely be included in the anti-tank sniper group, which will disable Trophy radars from a SVD or other rifle with a telescopic sight, so that their partners can then hit the tank out of portable equipment.
The recognition of the completion of the Merkava’s career as the main fighting vehicle of the AOI is that the Defense Research and Development Department of the Israel Defense Ministry embarked on the implementation of the Rakiya-Rakia project - (רקיע) - “Neosvod” to create a promising armored platform consisting of a set of specialized armored vehicles designed to replace the existing tanks, infantry fighting vehicles, self-propelled artillery installations, engineering vehicles and BREM.
The weight of one combat unit created on the Rakia platform is determined at the level from 35 to 40 tons. The main type of protection is considered to be a promising SAZ, which is capable of intercepting, inter alia, armor-piercing sub-caliber shells. During 2013, it is planned to prepare tactical and technical requirements and tender documentation for the creation of a promising platform for holding a competition among armored vehicle manufacturers. Planned term of putting into service - 2020 year.
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