Main battle tank

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"Battle Tank" redirects here. For the video game, see Battle Tank (video game).
German Army Leopard 2A5 main battle tanks in August 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 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[edit]

Previous concepts[edit]

Prior to and during World War II tank design suffered from a number of limitations due largely to engine power and transmission capability. A designer could produce a tank with high maneuverability, armour, or a large gun, but generally not all three at the same time. Combined with tank theory which stressed high-speed dashes into the rear of the enemy's lines, these limitations led naturally to two classes of tanks.

The first, known variously as light tanks, cruiser tanks or even tankettes for the very smallest versions, were designed for outright speed. The concept was to exploit holes in the enemy lines and run far into the rear areas in self-supporting armoured groups. This would disrupt enemy logistics and command-and-control, as well as delay the movement of reserves to the front. It was believed operations of this sort would undermine or completely destroy the ability for the front-line troops to continue battle.

To create those holes in the line, a second class known as heavy tanks or infantry tanks, were designed to work in concert with front-line infantry. As these were expected to move forward at the same speed as the men, higher speeds were not required and the engine power could instead be used to carry a much greater load. Infantry tanks featured much larger amounts of armour, heavier guns, and more track area to allow them to cross a shell-riddled battlefield.

A final class evolved during the war, the dedicated tank destroyer. These were generally conversions of existing tank designs, lightened in order to allow them to carry much larger guns.

Trial by fire[edit]

In spite of a great amount of theory and pre-war testing, the plans for armoured combat quickly proved themselves outdated. The battlefield did not bog down like it did in World War I and tended to be much more mobile. This was especially evident in the great sweeping battles in North Africa and the Soviet Union, where armoured forces executed drives of hundreds of miles. In these cases the problems with having two designs became especially evident; the tanks able to go toe-to-toe with the enemy were generally found miles to the rear, trying to catch up. Those able to maintain the drive were lightly armoured, and proved easy prey for enemy anti-tank guns and rifles. Tank destroyers were particularly derided, invariably finding themselves in the wrong place at the wrong time, attacked by infantry when on their own and rarely finding their intended prey.

This led to the emergence of designs with slightly greater armour, able to defeat anti-tank rifles and most smaller guns. As these appeared, the tank's own weapons had to grow larger in order to deal with enemy tanks with the same level of armour. This evolution led to the medium tank, which dominated combat in the second half of the war. Generally these designs massed about 25-30 tonnes, were armed with cannons around 75 mm, and powered by engines in the 400 to 500 hp range. Notable examples include the Soviet T-34, the most-produced tank to that time, the German Panzer IV, and the US M4 Sherman. The widespread production of these designs led to most others being pushed out of service or into niche roles.

Emergence of the MBT[edit]

Centurion Mk 3

Meanwhile the rapid increase in engine power in the aviation world had trickle-down effects in the tank world. An especially notable example was the deal arranged between Rolls-Royce and Rover, which led to Rolls gaining access to early jet engines while Rover took over development of the Rolls-Royce Merlin engine for tank use. The latter, the 600 bhp Rolls-Royce Meteor, offered such a great improvement in power that the resulting Cromwell and related designs were considered cruisers (light or medium tanks) while offering firepower and armour similar to the infantry tanks. Continued development of the basic Cromwell design led eventually to the Centurion. This design's armour was able to defeat all small and medium anti-tank guns, mounted a gun able to defeat even the largest enemy tanks, and offered manoeuvrability even better than earlier light tank designs. It was so flexible that they referred to it as the "universal tank", and it formed the backbone of post-war British Army tank units.

Cold War[edit]

A surplus of effective WWII-era designs in other forces, notably the US and Soviet Union, led to slower introductions of similar designs on their part. By the early 1950s these designs were clearly no longer competitive, especially in a world of shaped charge weapons, and new designs rapidly emerged from most armed forces.

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. Also, the heaviest tanks were unable to use most existing bridges. The World War II concept of heavy tanks, armed with the most powerful guns and heaviest armor, became obsolete because the large tanks were too expensive and just as vulnerable to damage by mines, bombs, rockets and artillery. 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 guns.[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 attacks from above by combat aircraft such as helicopters also resulted in an effective counter to nuclear explosion radiation.[7]

By the late 1970s, MBTs were manufactured by China, 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 devastated the Soviet Union's fighting capability.[9] The Soviet Union made novel advancements to the weapon systems including mechanical autoloaders and anti-tank guided missiles. Autoloaders were introduced to replace the human loader, permitting the turret to be reduced in size, making the target smaller and less visible,[4] while missile systems were added to extend the range at which a vehicle could engage a target and thereby 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]

Persian Gulf War[edit]

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

Asymmetrical warfare[edit]

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

The United States Army used 1,100 M1 Abrams in the course of the Iraq War. They proved 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 proved to be valuable in urban combat; at the Battle of Fallujah the United States Marines brought in two extra companies of M1s.[14] Britain deployed its Challenger 2 tanks to support its operations in southern Iraq.

Nations such as 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] Small unmanned turrets on top of the cupolas called remote weapon stations armed with machineguns or mortars provide improved defence and enhance crew survivability. Experimental tanks with unmanned turrets locate crew members in the heavily armored hull, improving survivability and reducing the vehicle's profile.[17]

Technology is reducing the weight and size of the modern MBT.[18] 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 warfare threats in the foreseeable future. The obsolescence of the tank has been asserted, but the history of the late 20th and early 21st century suggested that MBTs were still necessary.[19]

Design[edit]

A main battle tank has been officially described as "a self-propelled armoured fighting vehicle, capable of heavy firepower, primarily of a high muzzle velocity direct fire main gun necessary to engage armoured and other targets, with high cross-country mobility, with a high level of self-protection, and which is not designed and equipped primarily to transport combat troops."[20]

Overview[edit]

Countermeasures[edit]

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

Originally, most MBTs relied on 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 the Soviet Union.

MBT armor is concentrated at the front of the tank, where it is layered up to 33 centimetres (13 in) thick.[21]

The (Russian made) Indian T-90 Bhishma 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 M1 Abrams tanks serving in Iraq.

Other defensive developments focused on improving the strength of the armor itself; one of the notable advancement coming from the British with the development of Chobham armour 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 1950–60s–era rocket-propelled grenades with negligible damage. It is much less efficient against later models of RPGs. For example the RPG-29 from the 1980s is able to penetrate the frontal hull armour of the Challenger II[23][24]

Weaponry[edit]

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,[25] but have been diligently developed by the Soviet Union, who even retrofitted them to T-55 tanks, in an effort to double the effective range of the vehicle's fire. 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, an 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/Ukrainian T-64, T-72, T-80 T-84 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.[26] 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 than 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 60 cm/2 cm rod, 19g/cm3, @ 1,750 m/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.[27]

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[edit]

T-64BM Bulat on parade, a Ukrainian Ground Forces upgrade of the T-64, produced by the KMDB
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 Leopard 2). The extreme weight of vehicles of this type (45-70 tons) also limits their speed. They are usually equipped with a 1,200–1,500 hp (890–1,120 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 Italian Ariete. Its relatively low weight (54 tonnes) facilitates mobility, especially while crossing bridges.

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 and to the fire control system. Also, propulsion systems are not produced in high enough quantities to take advantage of economies of scale.[28]

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.[29] 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.[30] 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.[31] 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.[31] Where well maintained roads allow it, wheeled tank transporters can be used.[32]

The difficult task of resupply is usually accomplished with large trucks.[33]

Storage[edit]

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.[34]

The Israeli Merkava can even accommodate crewmembers displaced from a destroyed vehicle in its ammunition compartment.[29]

Crew[edit]

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[edit]

U.S. Marines during the Iraq War ride on an M1A1 Abrams tank in April 2003.

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.[31]

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.[35]

Main battle tanks have significantly varied characteristics. Procuring too many varieties can place a burden on tactics, training, support and maintenance.[36]

The MBT has a positive morale effect on the infantry it accompanies.[37] It also instills fear in the opposing force who can often hear and even feel their arrival.[12]

Procurement[edit]

Research and development[edit]

Manufacture[edit]

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

MBT production is increasingly being outsourced to wealthy nations. 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.[31]

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.[38]

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

Marketing[edit]

Several MBT models, such as the AMX-40 and OF-40, were marketed almost solely as export vehicles.[31]

Several tank producers, such as Japan and Israel, choose not to market their creations for export.[31] Others have export control laws in place.

See also[edit]

References[edit]

Notes
  1. ^ House (1984), Toward Combined Arms Warfare:A Survey of 20th-Century Tactics, Doctrine, and Organization
  2. ^ Tranquiler, Roger, Modern Warfare. A French View of Counterinsurgency, trans. Daniel Lee, "Pitting a traditional combined armed force trained and equipped to defeat similar military organisations against insurgents reminds one of a pile driver attempting to crush a fly, indefatigably persisting in repeating its efforts." 
  3. ^ Советская Военная Энциклопедия. Под ред. Гречко А.А. - М.: Воениздат, 1976–80 гг., в 8-и томах, статья «Танк» (Soviet Military Encyclopedia)
  4. ^ a b c Thomas W. Zarzecki (2002). Arms Diffusion: The Spread of Military Innovations in the International System. Psychology Press. p. 212. ISBN 0-415-93514-8. Retrieved 5 April 2011. 
  5. ^ T-64 manual ("Танк Т-64А. Техническое описание и инструкция по эксплуатации. 1984") state T-64 as "main battle" tank, while previous T-62 and T-55 (in corresponding military manuals, like "Танк Т-62. Руководство по материальной части и эксплуатации. 1968") stated as "medium" tanks
  6. ^ MIL-T-45308 state "Tank, Main Battle, 105MM Gun, M60", while MIL-T-45148 state "TANK, COMBAT, FULL-TRACKED, 90MM GUN, M48A2"
  7. ^ AcademicJohn Harris and Andre Gsponer (1986). Armour defuses the neutron bomb. Reed Business Information. p. 47. Retrieved 29 July 2011. 
  8. ^ Academic American encyclopedia, Volume 2. Aretê Pub. Co., 1980. 1980. p. 177. Retrieved 4 April 2011. 
  9. ^ David C. Isby (1988). Weapons and tactics of the Soviet Army. Jane's. Retrieved 4 April 2011. 
  10. ^ Daniel H. Else (III.) (2008). "Chapter 3". Bias in weapon development. ProQuest. p. 62. Retrieved 12 March 2012. 
  11. ^ Canadian Institute of Strategic Studies (1993). The Canadian strategic forecast. Canadian Institute of Strategic Studies. p. 73. Retrieved 4 April 2011. 
  12. ^ a b c d e f Chris McNab, Hunter Keeter (2008). Tools of violence: guns, tanks and dirty bombs. Osprey Publishing. Retrieved 6 April 2011. 
  13. ^ Komarow, Steven (2005-03-29). "Tanks take a beating in Iraq". USA Today. Retrieved 2010-04-09. 
  14. ^ Komarow, Steven (2005-03-29). "Tanks adapted for urban fights they once avoided". USA Today. Retrieved 2010-04-09. 
  15. ^ Anthony H. Cordesman (2006). Arab-Israeli Military Forces in an Era of Asymmetric Wars. Greenwood Publishing Group. ISBN 0-275-99186-5. Retrieved 14 February 2011. 
  16. ^ Anthony H. Cordesman, Aram Nerguizian, Ionut C. Popescu (2008). Israel and Syria: The Military Balance and Prospects of War. ABC-CLIO. p. 99. ISBN 978-0-313-35520-2. Retrieved 1 April 2011. 
  17. ^ a b c d Neville Brown (2009). The Geography of Human Conflict: Approaches to Survival. Sussex Academic Press. p. 254. ISBN 978-1-84519-169-6. Retrieved 5 April 2011. 
  18. ^ Stan Krasnoff (2008). A Claytons Defense. Strategic Book Publishing. p. 35. Retrieved 5 April 2011. 
  19. ^ Asia-Pacific defence reporter, Volume 30. Asia-Pacific Defence Publications. 2004. Retrieved 2 April 2011. 
  20. ^ Treaty on conventional armed forces in Europe. Organization for Security and Co-operation in Europe. 1989. p. 3. Retrieved 4 April 2013. 
  21. ^ Stan Windass, Paul Walker (1985). Avoiding Nuclear War: Common Security as a Strategy for the Defence of the West. Brassey's Defence Publishers. p. 38. Retrieved 4 April 2011. 
  22. ^ a b Richard Holmes, Hew Strachan, Chris Bellamy (2001). The Oxford Companion to Military History. Oxford University Press. pp. 493, 902. Retrieved 4 April 2011. 
  23. ^ "Defence chiefs knew 'invincible' tank armour could be breached". Daily Mail. 24 April 2007. 
  24. ^ Sean Rayment (May 12, 2007 *). "MoD kept failure of best tank quiet". Sunday Telegraph.  Check date values in: |date= (help)
  25. ^ African armed forces journal. Military Publications Ltd. 1994. p. 10. 
  26. ^ Jeff Groman (1985). Weapons of War. Gallery Books. p. 126. Retrieved 18 February 2011. 
  27. ^ Thomas W. Zarzecki (2002). Arms Diffusion: The Spread of Military Innovations in the International System. Psychology Press. Retrieved 18 February 2011. 
  28. ^ National Research Council (U.S.). Committee on Adiabatic Diesel Technology (1987). A review of the state of the art and projected technology of low heat rejection engines: a report. National Academies. p. 108. Retrieved 2 April 2011. 
  29. ^ a b Robin Fletcher (May 1995). "The Crewing and Configuration of the Future Main Battle Tank" (PDF). ARMOR: 6-8, 42, & 43. Retrieved 4 May 2011.  (HTML version)
  30. ^ Michael Chichester, John Wilkinson (1987). British defence: a blueprint for reform. Brasseys Defence. p. 126. Retrieved 4 April 2011. 
  31. ^ a b c d e f Mary Kaldor, Basker Vashee, World Institute for Development Economics Research (1998). [Restructuring the Global Military Sector: The end of military Fordism Restructuring the Global Military Sector: The End of Military Fordism]. Continuum International Publishing Group. p. 108. ISBN 1-85567-428-9. Retrieved 4 April 2011. 
  32. ^ Brian MacDonald (1997). Military Spending in Developing Countries: How Much Is Too Much?. McGill-Queen's Press - MQUP. p. 136. ISBN 0-88629-314-6. Retrieved 2 April 2011. 
  33. ^ Michael Green (2008). War Stories of the Tankers: American Armored Combat, 1918 to Today. Zenith Imprint. p. 281. ISBN 978-0-7603-3297-9. Retrieved 4 April 2011. 
  34. ^ David Miller (2000). The illustrated directory of tanks of the world. Zenith Imprint. p. 384. ISBN 0-7603-0892-6. Retrieved 4 April 2011. 
  35. ^ David Eshel, Bill Sweetman (25 April 2011). "New Designs Suit Tanks For Asymmetric War". The McGraw-Hill Companies, Inc. Retrieved 3 May 2011. 
  36. ^ Saudi Arabia Enters the Twenty-first Century: The Military and International Security Dimensions. Greenwood Publishing Group. 2003. p. 140. Retrieved 1 April 2011. 
  37. ^ Stanley Sandler (2002). Ground Warfare: An International Encyclopedia, Volume 1. ABC-CLIO. p. 59. ISBN 1-57607-344-0. Retrieved 5 April 2011. 
  38. ^ United States. Congress. House. Committee on Appropriations (1990). Department of Defense Appropriations for 1991, Part 6. U. S. Govt. Print. Off. Retrieved 4 April 2011.