Merkava is optimized for crew survival and rapid repair of battle damage. Through the use of spaced-armor techniques and quick-replacement modular designs, the design team was able to incorporate composite armor, a derivative of rolled homogeneous armor (RHA) and Chobham armour. Additionally, the space between the inner and outer hulls is filled with diesel fuel—an economical storage method and a means of defeating HEAT rounds.
Following the model of contemporary self-propelled howitzers, the turret assembly is located nearer the rear than in most main battle tanks. This gives the crew additional protection against a frontal attack by putting the engine between them and the attack. This arrangement also creates more space in the rear of the tank that allows increased storage capacity, as well as a rear entrance to the main crew compartment allowing easy access even under enemy fire. This allows the tank to be used as a platform for medical disembarkation, a forward command and control station, and an armored personnel carrier. The rear entrance's clamshell-style doors provide overhead protection when off- and on-loading cargo and personnel.
Merkava Mark I
The Merkava Mark I is the original design created as a result of Israel Tal's decision, and was fabricated and designed for mass production. The Merkava Mark I weighed 63 tonnes and had a 900 horsepower (670 kW) diesel engine, with a power to weight ratio of 14 hp/ton. It was armed with the 105 millimeter M68 main gun (a licensed copy of the British Royal Ordnance L7), two 7.62 mm machine guns for anti-infantry defense, and a 60 mm mortar mounted externally, with its operator not completely protected by the tank's hull.
The Merkava was first used in combat during the 1982 Lebanon War where Israel deployed 180 units. After the war many adjustments and additions were noted and designed, the most important being that the 60 millimeter mortar needed to be installed within the hull and engineered for remote firing. A shot trap was found beneath the rear of the turret bustle where a well-placed shot could jam the turret completely. Installation of chain netting to disperse and destroy rocket propelled grenades and anti-tank rockets before impacting the primary armor increased survivability.
Merkava Mark II
The Merkava Mark II was first introduced into general service in April 1983 and incorporated several upgrades as a result of the previous incursion into Lebanon. The new tank was optimized for urban warfare and low intensity conflicts, with a weight and engine no greater than the Mark I.
The Merkava Mark II used the same 105 millimeter main gun and 7.62 millimeter machine guns as the Mark I, but the 60 millimeter mortar was redesigned during construction to be located within the hull and configured for remote firing to remove the need to expose the operator to enemy small-arms fire. An Israeli-designed automatic transmission and increased fuel storage for increased range was installed on all further Mark IIs. Anti-rocket netting was fitted for increased survivability against infantry equipped with anti-tank rockets.
Many minor improvements were made to the fire-control system. Updated meteorological sensors, crosswind analyzers, and thermographic optics and image intensifiers gave greater visibility and battlefield awareness.
Incrementally improved versions of the original The Merkava Mark II were designated:
- The Merkava Mark IIB, with thermal optics and unspecified updates to the fire control system.
- The Merkava Mark IIC, with more armor on the top of the turret to improve protection against attack from the air.
- The Merkava Mark IID, with next-generation modular composite armor on the chassis and turret.
The Merkava Mark III was introduced in December 1989, and had many major upgrades to the drivetrain, powertrain, armament, and safety systems. The most prominent addition was the incorporation of the locally-developed IMI 120 mm gun based on German Rheinmetall 120mm Gun. This gun and a larger 1,200 horsepower (890 kW) diesel engine increased the total weight of the tank to 65 tonnes, but the larger engine increased the maximum cruising speed to 60 km/h.The turret was re-engineered for movement independent of the tank chassis, allowing it to track a target regardless of the tank's movement. Many other improvements were made, including:
- External two-way telephone for secure communications between the tank crew and dismounted infantry,
- Upgraded ammunition storage containers to minimize ammunition cook-off,
- Addition of laser designators,
- Incorporation of the Kasag modular armor system, designed for rapid replacement and repair in the battlefield and for quick upgrading as new designs and sophisticated materials become available,
- Creation of the The Merkava Mark IIIB, with unspecified armor upgrades.
The 1995 The Merkava Mark III BAZ (Hebrew Acronym signifying Barak Zoher) had many improved and additional systems including:
- Upgraded fire-control system components, from Electro Optics Industries (EL-OP) and Elbit Ltd, provides the tank with the ability to engage moving targets while on the move (an automatic target tracker),
- NBC protection systems,
- Locally-developed central air-conditioning system,
- Added improvements in ballistic protection,
- The The Merkava Mark IIID had modular composite armor on the chassis and turret.
The last generation of the Merkava Mark III class was the Mark IIID Dor-Dalet (Hebrew: Fourth Generation), which included several components as prototypes to be introduced in the Mark IV.
- Upgraded and strengthened tracks (built by Caterpillar, designed in Israel),
- Installation of the R-OWS.
The Merkava Mark IV is the latest generation of the Merkava and has been in development since 1999. Its development was first announced in an October 1999 edition of the Bamachaneh (at The Camp) military publication.
Design features
The new model has a more robust fire-control system, the Knight Mark 4, produced by El-Op. The Merkava Mark IV has improved armor on all sides, including the top and underbelly, and is optimized for urban combat. The underside of the tank is reinforced with a modular, removable V-shaped "belly armor pack."
Ammunition is stored in individual fire-proof canisters, which reduce the chance of tank rounds cooking-off in the case of a fire inside the tank. As a result, the turret is classified as "dry", meaning that no active rounds are stored above the turret line.
Some features, such as hull shaping, exterior non-reflective paints, and shielding for engine heat plumes mixing with air particles to confuse enemy thermal imagers, were carried over from the IAI Lavi program of the Israeli Air Force to reduce the battlefield signature of the Merkava series tanks.
The Merkava Mark IV includes the larger 120 millimeter main gun of the previous versions but is capable of firing a wider variety of ammunition, including HEAT and sabot rounds like the APFSDS kinetic energy penetrator, using an electrical semi-automatic revolving magazine for 10 rounds. It also includes the incorporation of a much larger 12.7 mm machine gun for anti-vehicle operations (most commonly used against technicals).
Upgraded fire control system
The new fire-control system enables the Merkava to operate as an anti-helicopter platform and is capable of detecting and destroying armored attack helicopters such as the French Gazelle and the ubiquitous Russian Mil Mi-24, both used by Israel's neighbors.
Upgraded tracks
Digital battlefield management system
A new and very sophisticated Israeli Elbit Systems BMS has been designed, constructed, and tested. It is a centralised system which displays battlefield data on color screens. It collects data from tracked units and UAVs deployed in theater, and immediately distributes it in encrypted form to all other units equipped with BMS in a given theater.
