German Leopard 2A5 main battle tanks in 2010

A main battle tank (MBT), also known as a battle tank or universal tank, is a tank that fills the heavy direct fire role of many modern armies. They were originally conceived to replace the light, medium, heavy and super-heavy tanks. Development was spurred onwards in the Cold War with the development of lightweight composite armor. They are still supplemented in some armies with light tanks.

Today, main battle tanks are considered a key component of modern armies.^[1] Modern MBTs seldom operate alone, as they are organized into armored units which involve the support of infantry, who may accompany the MBTs in infantry fighting vehicles. They are also often supported by surveillance or ground-attack aircraft.^[2]

History[link]

Cold War[link]

Centurion Mk 3

The concept of the medium tank gradually evolved into the MBT in the 1960s,^[3] as it was realized that medium tanks could carry guns (such as the US 90 mm, Soviet 100 mm, and especially the British L7 105 mm) that could penetrate any practical level of armor at long range. The World War II concept of heavy tanks, armed with the most powerful guns and heaviest armor, became obsolete because they were as vulnerable as other vehicles to the new medium tanks.^{[citation needed]} Likewise, World War II had shown that lightly armed and armored tanks were of limited value in most roles. Even reconnaissance vehicles had shown a trend towards heavier weight and greater firepower during World War II; speed was not a substitute for armor and firepower.

Soviet T-64 undergoing decontamination

An increasing variety of anti-tank weapons and the perceived threat of a nuclear war prioritized the need for additional armor. The additional armor prompted the design of even more powerful cannons.^[4] The main battle tank thus took on the role the British had once called the 'Universal tank', exemplified by the Centurion, filling almost all battlefield roles. Typical main battle tanks were as well armed as any other vehicle on the battlefield, highly mobile, and well armored. Yet they were cheap enough to be built in large numbers. The first Soviet main battle tank was the T-64^[5](T-54/55 and T-62 then considered "medium" tanks) and the first American MBT was the M60 Patton.^[6]

An early model M60 "Patton"

The adoption of ceramic armor as well as greater armor coverage necessitated by non-frontal attacks from combat helicopters also resulted in an effective counter to nuclear explosion radiation.^[7]

By the late 70s, MBTs were manufactured by France, West Germany, Britain, India, Japan, the Soviet Union, Sweden, Switzerland, and the United States.^[8]

The Soviet Union war doctrine depended heavily on the main battle tank. Any weapon advancement making the MBT obsolete could have severely devastated the Soviet Union's fighting capability.^[9] The Soviet Union made advancements to the gun system. Mechanical autoloaders were introduced to replace the human loader. This permitted the turret to be reduced in size making the target smaller and less visible.^[4] Missile systems were added to extend range of the gun and to enhance the first-round hit probability.^[4]

The United States's experience in the Vietnam War contributed to the idea among army leadership that the role of the main battle tank could be replaced with attack helicopters. During the Vietnam War, helicopters and missiles competed with MBTs for research money.^[10]

Gulf War[link]

Though the Gulf War reaffirmed the role of main battle tanks, MBTs were outperformed by the attack helicopter.^[11] Other strategists asserted that the MBT was entirely obsolete because of the efficacy and speed with which coalition forces neutralized Iraqi armor.^[12]

Asymmetrical warfare[link]

A German Leopard 2 in the PSO-version, prepared for asymmetrical warfare

As of 2005, there were 1,100 M1 Abrams used by the United States Army in the course of the Iraq War. They have proven to have an unexpectedly high vulnerability to improvised explosive devices.^[13] A relatively new type of remotely-detonated mine, the explosively formed penetrator was used with some success against American armored vehicles. However, with upgrades to their rear armor, M1s have proven to be valuable in urban combat; at the Battle of Fallujah, the United States Marines brought in two extra companies.^[14] Britain deployed its Challenger 2 tanks to support its operations in southern Iraq.

Nations like Israel are reducing the size of their tank fleet and procuring more advanced models.^[15]

Advanced armor has not improved vehicle survivability but has reduced crew fatalities.^[16] Unmanned cupolas called remote weapon stations enhance crew survivability. Experimental tanks with unmanned turrets locate crewmembers in the heavily armored hull improving survivability and reducing the vehicle's profile.^[17]

The obsolescence of the tank has been asserted from time-to-time but recent history suggests that the MBTs are still necessary.^[18] Technology is reducing the weight and size of the modern MBT.^[19] A British military document from 2001 indicated that the British Army would not procure a replacement for the Challenger 2 because of a lack of conventional threats in the foreseeable future.^[20]

Design[link]

Overview[link]

1. Periscope 2. Gun mantlet 3. Coaxial gun 4. Bore evacuator 5. Main gun 6. Driver's optics 7. Driver's hatch 8. Glacis plate 9. Continuous track 10. Machine gun ammunition 11. Commander's machine gun 12. Hatch or cupola 13. Gun turret 14. Turret ring 15. Hull 16. Engine air intake 17. Engine compartment 18. Armored skirt 19. Drive sprocket 20. Link 21. Road wheel

Countermeasures[link]

The Challenger II is equipped with Dorchester armour, an advanced composite armour.

Originally, most MBTs relied on traditional steel armor to defend against various threats. As newer threats emerged, however, the defensive systems used by MBTs had to evolve to counter them. One of the first new developments was the use of Explosive reactive armor (ERA), developed by Israel in the early 1980s to defend against the shaped-charge warheads of modern anti-tank guided missiles and other such high-explosive anti-tank (HEAT) projectiles. This technology was subsequently adopted and expanded upon by the United States and Soviet Union.

MBT armor is concentrated at the front of the tank where it is layered up to a third of a meter thick.^[21]

The Indian T-90S has a two-tier protection system.

Missiles are cheap and cost-effective anti-tank weapons.^[22] ERA can be quickly added to vehicles to increase their survivability. However, the detonation of ERA blocks creates a hazard to any supporting infantry near the tank. Despite this drawback, it is still employed on many Russian MBTs, the latest generation Kontakt-5 being capable of defeating both HEAT and kinetic energy penetrator threats. The Soviets also developed systems designed to more actively neutralize hostile projectiles before they could even strike the tank, namely the Shtora and Arena systems. Recently, the United States has adopted similar technologies in the form of the Missile Countermeasure Device and as part of the Tank Urban Survival Kit used on Abrams tanks serving in Iraq.

Other defensive developments focused on improving the strength of the armor itself; the most notable advancement coming from the British with the development of chobham armor in the 1970s. It was first employed on the American M1 Abrams and later the British Challenger 1. Chobham armor uses a lattice of composite and ceramic materials along with metal alloys to defeat incoming threats, and proved highly effective in the conflicts in Iraq in the early 1990s and 2000s; surviving numerous impacts from rocket-propelled grenades with negligible damage.

Weaponry[link]

Merkava Mk 3d BAZ of the Israel Defense Forces firing its main gun.

Main battle tanks are equipped with a main tank gun, and at least one machine gun.

MBT main guns are generally between 90 and 130 mm caliber, and can fire both anti-armor and, more recently, anti-personnel rounds. The cannon serves a dual role, able to engage other armored targets such as tanks and fortifications, and soft targets such as light vehicles and infantry. It is fixed to the turret, along with the loading and fire mechanism. Modern tanks utilize a sophisticated fire-control system, including rangefinders, computerized fire control, and stabilizers, which are designed to keep the cannon stable and aimed even if the hull is turning or shaking, making it easier for the operators to fire on the move and/or against moving targets. Gun-missile systems are complicated and have been particularly unsatisfactory to the United States who abandoned gun-missile projects such as the M60A2 and MBT-70.^[23] The MBT's role could be compromised because of the increasing distances involved and the increased reliance on indirect fire.^[17] The tank gun is still useful in urban combat for precisely delivering powerful fire while minimizing collateral damage.^[12]

French Leclerc

High explosive anti-tank (HEAT), and some form of high velocity kinetic energy penetrator, such as APFSDS (Armor-piercing fin stabilized discarding sabot) rounds are carried for anti-armor purposes. Anti-personnel rounds such as high explosive or high explosive fragmentation have dual purpose. Less common rounds are beehive anti-personnel rounds, and High explosive squash head (HESH) rounds used for both anti-armor and bunker busting. Usually, a MBT carries 30-50 rounds of ammunition for its main gun, usually split between HE, HEAT and kinetic energy penetrator rounds. Some MBTs may also carry smoke or white phosphorus rounds. Some MBTs are equipped with an autoloader, such as the French Leclerc, or the Russian T-64, T-72, T-80 and T-90 and, for this reason, the crew can be reduced to 3 members. MBTs with an autoloader require one less crew member and the autoloader requires less space than its human counterpart, allowing for a reduction in turret size. Further, an autoloader can be designed to handle rounds which would be too difficult for a human to load.^[24] This reduces the silhouette which improves the MBT's target profile, however, with a manual loader, the rounds can be isolated within a blowout chamber, rather then a magazine within the turret, which could improve crew survivability. However, the force of a modern depleted uranium armor piercing fin discarding sabot round at the muzzle can exceed 6000KN.(a rough estimate, considering a uranium 60cm/2cm rod, 19g/cm3, @ 1750m/s) Composite+reactive armor could withstand this kind of force through its deflection and deformation, but with a second hit in the same area, an armor breach is inevitable. As such, the speed of follow up shots is crucial within tank to tank combat. ^[25]

As secondary weapons, an MBT usually uses between two and four machine guns to engage infantry and light vehicles. Many MBTs mount one heavy caliber anti-aircraft machine gun (AAMG), usually of .50 caliber (like the M2 Browning or DShK), which can be used against helicopters and low flying aircraft. However, their effectiveness is limited in comparison to dedicated anti-aircraft artillery. The tank's machine guns are usually equipped with between 500 and 3000 rounds each.

Mobility[link]

A former British Army Challenger 1

MBTs, like previous models of tanks, move on treads, which allow a decent level of mobility over most terrain including sand and mud. They also allow tanks to climb over most obstacles. MBTs can be made water-tight, so they can even dive into shallow water (5 m (16 ft) with snorkel). However, treads are not as fast as wheels; the maximum speed of a tank is about 65 km/h (40 mph) (72 km/h (45 mph) for the M1 Abrams). The extreme weight of vehicles of this type (60-70 tons) also limits their speed. They are usually equipped with a 1,200–1,500 hp (890–1,100 kW) engine (more than 25,000 cc (1,526 cu in)), with an operational range near 500 km (310 mi).

The German Army has prioritized mobility in its Leopard 2 which is considered the fastest MBT in existence.^[22]

The MBT is often cumbersome in traffic, much to the disdain of drivers who must share the road with it. The tracks can damage some roads after repeated use. Many structures like bridges do not have the load capacity to support an MBT. In the fast pace of combat it is often impossible to test the sturdiness of these structures. In the 2003 invasion of Iraq, an M1 Abrams attempting to cross a bridge to evade enemy fire plummeted into the Euphrates river when the bridge collapsed.^[12] Though appreciated for its excellent off-road characteristics, the MBT can become immobilized in muddy conditions.

Israeli Merkava Mark IV on a tank transporter.

The high cost of MBTs can be attributed in part to the high performance engine-transmission system. Also, propulsion systems are not produced in high enough quantities to take advantage of economies of scale.^[26]

Crew fatigue limits the operational range of MBTs in combat. Reducing the crew to three and relocating all crewmembers from the turret to the hull could provide time to sleep for one off-shift crewmember located in the rear of the hull. In this scenario, crewmembers would rotate shifts regularly and all would require cross-training on all vehicle job functions.^[27] Cargo aircraft are instrumental to the timely deployment of MBTs. The absence of sufficient numbers of strategic airlift assets can limit the rate of MBT deployments to the number of aircraft available.^[28] The only aircraft capable of transporting full-featured MBTs with ease are the C-5 Galaxy, Antonov An-22, and Antonov An-124 which are declining in number.

Military planners anticipate that the airlift capability for MBTs will not improve in the future.^[29] To date, no helicopter has the capability to lift MBTs.^[12] Rail and road are heavily used to move MBTs nearer to the battle, ready to fight in prime condition.^[29] Where well maintained roads allow it, wheeled tank transporters can be used.^[30]

The difficult task of resupply is usually accomplished with large trucks.^[31]

Storage[link]

Main battle tanks have internal and external storage space. Internal space is reserved for ammunition. External space enhances independence of logistics and can accommodate extra fuel and some personal equipment of the crew.^[32]

The Israeli Merkava can even accommodate crewmembers displaced from a destroyed vehicle in its ammunition compartment.^[27]

Crew[link]

Emphasis is placed on selecting and training main battle tank crew-members. The crew must perform their tasks faultlessly and harmoniously so commanders select teams taking into consideration personalities and talents.^[12]

Role[link]

U.S. Marines ride an M1 Abrams.

The main battle tank fulfills the role the British had once called the 'universal tank', filling almost all battlefield roles. They were originally designed in the Cold War to combat other MBTs.^[17] The modern light tank supplements the MBT in expeditionary roles and situations where all major threats have been neutralized and excess weight in armor and armament would only hinder mobility and cost more money to operate.

Reconnaissance by MBTs is performed in high-intensity conflicts where reconnaissance by light vehicles would be insufficient due to the necessity to 'fight' for information.^[29]

In asymmetric warfare, main battle tanks are deployed in small highly concentrated units. MBTs fire only at targets at close range and instead rely on external support such as unmanned aircraft for long range combat.^[33]

Main battle tanks have significantly varied characteristics. Procuring too many varieties can place a burden on tactics, training, support and maintenance.^[34]

The MBT has a positive morale effect on the infantry it accompanies.^[35] It also instills fear in the opposing force who can often hear and even feel their arrival.^[12]

Procurement[link]

Research and development[link]

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Manufacture[link]

Mechanics at Anniston Army Depot line up an M1 Abrams turret with its hull.

MBT production is increasingly being outsourced to wealthy nations. Tank manufacturers are primarily located in the northern hemisphere, whereas the major consumers are located in the Middle-East. Countries that are just beginning to produce tanks are having difficulties remaining profitable in an industry that is increasingly becoming more expensive through sophistication of technology. Even some large-scale producers are seeing declines in production. Even China is divesting many of its MBTs.^[29]

The production of main battle tanks is limited to manufacturers that specialize in combat vehicles. Commercial manufacturers of civilian vehicles cannot easily be repurposed as MBT production facilities.^[36]

Prices for MBTs have more than tripled from 1943–2011, although this pales in comparison with the price increase in fighter aircraft from 1943-1975.^[17]

Marketing[link]

This section requires expansion.

Several MBT models, such as the AMX-40 and OF-40, were marketed almost solely as export vehicles.^[29]

Several tank producers, such as Japan and Israel, choose not to market their creations for export.^[29] Others have export control laws in place.

See also[link]

Wikimedia Commons has media related to: Main battle tanks

• Light tank
• Cruiser tank
• Infantry tank
• List of main battle tanks by country
• List of main battle tanks by generation

References[link]

Notes