The new version of MBK MERKAVA, the Mk-4 appeared for the first time in public in June of the 2002, constitutes the fourth generation of the original Mk-1 model, whose design began at the end of the Kippur war and saw the first operational employment during the 1982 Lebanon campaign.
The MERKAVA Mk-4, which with its 65 tons is perhaps the heaviest wagon in the world, is equipped with the 251 / 120 mm smooth-core MG-44 cannon, built in Israel by the IMI Slavin Land System Division and designed to tolerate internal pressures higher than the previous 120 / 44 of the Rheinmetall, in order to allow a greater initial speed depending on the use of an advanced type of kinetic energy ammunition. The recoiling mass of the MG-251 is 2.000 kg, the same as the previous German model, but its recoil absorption system is more compact. The cannon can employ all types of ammunition existing today, including APFSDS kinetic energy, HEAT (High-Explosive Antitank), APAM (Antipersonnel / Antimaterial), and the LAHAT (Lase-Homing Antitank) laser guided missile.
The servant can pick up the projectiles from a warehouse made up of two rotating drums arranged in the rear fa├žade. The semi-automatic loading system, which contains 10 ready-to-use shots of four different types, which can be selected automatically, is electronically activated and the selection of the ready-to-use shots is controlled by means of a microprocessor.
The wagon is equipped with an advanced system for integrated shooting control, focused on an improved version of the Elbit KNIGHT Mk-3 viewer, which uses ballistic calculations performed by a modern computer whose software is designed to take into account all the parameters that influence the ballistic equation. Next to the improved KNIGHT Mk-3, stabilized on two axes for the gunner, on the MK-4 there is also a panoramic observation system stabilized on two axles for the truck, both equipped with an advanced FLIR system (thermal chamber) and a TV screen for day and night observation channels, which greatly increase the probability of centering the target on the first shot.
An automatic second-generation tracking system (ATS) engages the target at a distance of a few kilometers, tracking it automatically whether it is moving vehicles on the ground, or helicopters flying at low altitude. The gunner's viewfinder then begins the fire sequence, independently of any evasive action that the target can perform when it realizes that it is under attack.
As far as protection is concerned, since the MERKAVA Mk-4 was designed for modern battlefields, maximum attention has been given to the improvement of the survivability capabilities of the third- and fourth-generation anti-tank systems, with particular attention to end-guide missiles equipped with a top attachment profile. To ensure maximum protection of the upper part of the turret, the servant's door has been removed. This makes it possible to use a wide range of modular protection systems - made of hybrid armor - on the turret sky itself, as well as on the entire surface of the wagon.For the perimeter defense the Mk-4 is equipped with the Amcoram laser alarm system LWS-2, whose sensors are able to detect approaching missiles immediately after launch. The LWS-2 incorporates an advanced defensive system, called TROPHY Active Protection System (APS), whose operation is based on the association of a search and tracking radar IAI Elta, which is intended for the detection of threats on arrival, with a launch device for hard-kill countermeasures. After the identification of a potentially dangerous device, the TROPHY automatically begins the interception process that neutralizes the threat at a safe distance. The radar subsystem consists of 4 fixed antennas of which 2 on the roof of the turret facing forward and the remaining 2 behind the rear wall of the same.
The two hard-kill countermeasure launchers are located on either side of the turret and each covers an arc of 210 ┬░. The TROPHY is effective, both against long-thrower missile missiles, and against short-throw systems and provides protection on 360 ┬░. It also has the ability to cope with threats from above.
The MK-4 propulsion system consists of a 1.500 Hp turbodiesel with 3.700 revolutions per minute, liquid-cooled, General Dynamics GD 883. Its most striking feature is its compactness. Compared to the LEUNARD 2 engine, it has a specific volume equal to 60% only; in particular the height is equal to 656 mm (against 845) while the width is limited to 940 mm (against 1.060).
The Mk-4 was used for the first time in Lebanon, during the SUMMER RAIN operation, and 18 of them were put out of action due to tandem charging anti-tank missiles. The losses, all things considered, high, since Hezbollah did not align any wagons to keep up with the Mk-4, were attributed to the gaps in the Armored Corps general training program and the lack of preparation both at the crew level and at the constituted units .
The Tsahal began to modify its operative doctrine, molding it on a concept of asymmetrical war, in which the adversary, which was previously conventional, has now become unconventional, and where the chariot, which first fought against enemy tanks and observed great distance, it must increasingly face small, heavily armed teams with anti-tank systems.
(photo: IDF / Rafael Advanced Defense Systems)