Definitions

Homogeneous armor

M1 Abrams

The M1 Abrams is a main battle tank produced in the United States. The M1 is named after General Creighton Abrams, former Army Chief of Staff and former commander of the 37th Armored Regiment. It is a well armed, heavily armored, and highly mobile tank designed for modern armored ground warfare. Notable features of the M1 Abrams include the use of a powerful gas turbine engine, the adoption of sophisticated composite armor, and separate ammunition storage in a blow-out compartment for crew safety. It is one of the heaviest tanks in service, weighing in at close to 70 tons.

The M1 Abrams entered U.S. service in 1980, replacing the M60 Patton and M48A5. It did, however, serve for over a decade alongside the improved M60A3, which had entered service in 1978. Three main versions of the M1 Abrams have been deployed, the M1, M1A1, and M1A2, incorporating improved armament, protection and electronics. These improvements, as well as periodic upgrades to older tanks have allowed this long-serving vehicle to remain in front-line service. It is the principal combat tank of the United States Army and Marine Corps, and the armies of Egypt, Kuwait, Saudi Arabia, and as of 2007, Australia.

Background

The first attempt to replace the aging M60 series of tanks was the abortive MBT-70, developed in partnership with West Germany. The M60 Patton was itself a gradual evolution of a design starting with the World War II era M26 Pershing, with a very tall profile, and average armor and weaponry compared to the contemporary Soviet designs. The MBT-70 was very ambitious, like many American weapons programs of the 1960s. It had a gun launched missile system, kneeling suspension, a driver housed in the turret, and various other ideas that ultimately proved unsuccessful. Cancellation of this project paved the way for the much more successful M1 Abrams tank, which did not incorporate most of the troublesome innovations tried by the MBT-70.

Development

The M1 Abrams was designed by Chrysler Defense (in 1979, General Dynamics Land Systems Division purchased Chrysler Defense Division) and is currently produced by General Dynamics Corporation in Lima, Ohio, and first entered US Army service in 1980. An improved version of the M1, the M1A1, was introduced in 1985. The M1A1 has the M256 120 mm smoothbore cannon developed by Rheinmetall AG of Germany for the Leopard 2, improved armor, and a CBRN protection system. The M1A2 is a further improvement of the M1A1 with a commander's independent thermal viewer and weapon station, position navigation equipment, digital data bus and a radio interface unit. The M1A2 SEP (System Enhancement Package) added digital maps, FBCB2 (Force XXI Battlefield Command Brigade and Below) capabilities, and an improved cooling system to maintain crew compartment temperature with the addition of multiple computer systems to the M1A2 tank.

Further upgrades include depleted uranium armor for all variants, a system overhaul that returns all A1s to like-new condition (M1A1 AIM), a digital enhancement package for the A1 (M1A1D), a commonality program to standardize parts between the U.S. Army and the Marine Corps (M1A1HC) and an electronic upgrade for the A2 (M1A2 SEP).

During Operations Desert Shield and Desert Storm and for Bosnia, some M1A1s were modified with armor upgrades. The M1 can be equipped with mine plow and mine roller attachments if needed. The M1 chassis also serves as a basis for the Grizzly combat engineering vehicle and the M104 Wolverine heavy assault bridge.

Over 8,800 M1 and M1A1 tanks have been produced at a cost of US$2.35–$4.30 million per unit, depending on the variant.

Design features

Armor

The Abrams is protected by Chobham armor, a further development of British "Burlington" armor. Chobham is a composite armor formed by spacing multiple layers of various alloys of steel, ceramics, plastic composites, and kevlar, giving an estimated maximum (frontal turret) 1320-1620 millimeters of RHAe versus HEAT (and other chemical energy rounds) and 940-960 mm versus kinetic energy penetrators. It may also be fitted with reactive armor over the track skirts if needed (as in the Urban Survival Kit) and Slat armor over the rear of the tank and rear fuel cells to protect against ATGMs. Fuel and ammunition are in armored compartments with blowout panels to protect the crew from the risk of the tank's own ammunition cooking off if the tank is damaged. Protection against spalling is provided by a kevlar liner. Beginning in 1987, M1A1 tanks received improved armor packages that incorporated depleted uranium (DU) mesh in their armor at the front of the turret and the front of the hull. Armor reinforced in this manner offers significantly increased resistance towards all types of anti-tank weaponry, but at the expense of adding considerable weight to the tank. Depleted uranium is 1.7 times heavier than lead.

The first M1A1 tanks to receive this upgrade were tanks stationed in Germany, since they were the first line of defense against the Soviet Union. US-based tank battalions participating in Operation Desert Storm received an emergency program to upgrade their tanks with depleted uranium armor immediately before the onset of the campaign. M1A2 tanks uniformly incorporate depleted uranium armor, and all M1A1 tanks in active service have been upgraded to this standard as well, the armor thickness is believed to be equivalent to 24 inches (610 mm) of RHA. The strength of the armor is estimated to be about the same as similar western, contemporary main battle tanks such as the Leopard 2. In the Persian Gulf War, Abrams tanks survived multiple hits at relatively close ranges from Iraqi T-72s and ATGMs. M829A1 "Silver Bullet" APFSDS rounds from other M1A1 Abrams were unable to penetrate the front and side armor (even at close ranges) in friendly fire incidents as well as an incident in which another Abrams tried to destroy an Abrams that got stuck in mud and had to be abandoned.

In addition to the advanced armor, some Abrams, are equipped with a Missile Countermeasure Device that can impede the function of guidance systems of semiactive control line-of-sight (SACLOS) wire and radio guided anti-tank missiles (Russian AT-3, AT-4, AT-5, AT-6 and the like) and thermally and infrared guided missiles (ATGM). This device is mounted on the turret roof in front of the Loader's hatch, and can lead some people to mistake Abrams fitted with these devices for the M1A2 version, since the Commander's Independent Thermal Viewer on the latter is mounted in the same place, though the MCD is box-shaped and fixed in place as opposed to cylindrical and rotating like the CITV.

In the chance that the Abrams does suffer damage resulting in a fire in the crew compartment, the tank is equipped with a halon fire-suppression system that automatically engages and extinguishes fires in seconds.

Armament

Main armament

M68A1 rifled gun The main armament of the original model M1 was the M68A1 105 mm rifled tank gun firing a variety of high explosive anti-tank (HEAT), high explosive, white phosphorus, and a highly efficient and lethal anti-personnel (multiple flechette) round. This gun is a license-built version of the British Royal Ordnance L7 gun. While being a reliable weapon and widely used by both NATO and former Warsaw Pact nations alike, a cannon with lethality beyond the 3 kilometer range was needed to combat newer armor technologies. To attain that lethality, projectile diameter needed to be increased. The M68A1's performance in terms of accuracy and armor-piercing penetration is on par with the M256A1 up to 3000 meters out, but beyond that range the 105mm projectile lacks the kinetic energy to defeat modern armor packages. M256 smoothbore gun

The main armament of the M1A1 and M1A2 is the M256A1 120 mm smoothbore gun, designed by Rheinmetall AG of Germany. The M256A1 is a variant of the Rheinmetall 120 mm L/44 gun carried on the German Leopard 2 on all variants up to the Leopard 2A5. Leopard 2A6 replaced the L/44 barrel with a longer L/55. The newer M256A1 is manufactured under license in the United States by Watervliet Arsenal, New York.

The M256A1 fires a variety of rounds. The M829A2 was developed specifically to address the threats posed by a Soviet T-90 or T-80U tank equipped with kontakt-5 Explosive Reactive Armor. It also fires HEAT shaped charge rounds such as the M830, the latest version of which (M830A1) incorporates a sophisticated multi-mode electronic sensing fuse and more fragmentation which allows it to be used effectively against armored vehicles, personnel, and low-flying aircraft. Unlike the Soviet-built tanks it was designed to go up against, the Abrams uses a manual loader rather than an automatic device, due to the belief that having a person reload the gun is faster and more reliable. This decision was proven out as the Soviet-era automatic loading system proved troublesome. Also important in the decision to use a crew member instead of an automatic loader during the XM-1 development was the fact that autoloaders of the day did not allow for separate ammunition storage in the turret.

The new M1028 120 mm anti-personnel canister cartridge was brought into service early for use in the aftermath of the 2003 invasion of Iraq. It contains 1,098 3/8 inch steel ball projectiles which spread from the muzzle to produce a shotgun effect lethal out to 600 m. The steel balls can be used to clear enemy dismounts, break up hasty ambush sites in urban areas, clear defiles, stop infantry attacks and counter-attacks and support friendly infantry assaults by providing covering fire. The Canister round is also a highly effective breaching round and can level cinder block walls and knock man-sized holes in reinforced concrete walls for infantry raids at distances up to 75 meters.

In addition to this, the new XM1111 (Mid-Range-Munition Kinetic Energy) is also in development. Essentially a cannon-fired guided round, it has a range of roughly 12 km and uses a KE warhead which is rocket assisted in its final phase of flight. This is intended to be the best penetrator yet, an improvement over the US 3rd generation DU penetrator (estimated penetration 790 mm).

Secondary armament

The Abrams tank has three machine guns:

  1. A .50 cal. (12.7 mm) M2 machine gun in front of the commander's hatch. On the M1, M1IP and M1A1, this gun is on a powered mount and can be fired using a 3× magnification sight, known as the Commander's Weapon Station (CWS for short), while the vehicle is "buttoned up" with all its hatches closed to protect the crew. On the M1A2 & M1A2SEP, this gun is on a flex mount (seen at right), the Commander having to expose himself to fire the weapon manually. With the forthcoming TUSK addon kit, an M2 or an Mk 19 grenade launcher can be mounted on the CROWS remote weapons platform (similar to the Protector M151 remote weapon station used on the Stryker family of vehicles). The upgrade variant called M1A1 Abrams Integrated Management (AIM) equips the .50 caliber gun with a thermal sight for accurate night and other low-visibility shooting.
  2. A 7.62 mm M240 machine gun in front of the loader's hatch on a skate mount. Some of these have been fitted with gun shields during the ongoing conflict in Iraq as seen in the image at right, as well as night-vision scopes for low-visibility engagements.
  3. A second 7.62 mm M240 machine gun in a coaxial mount to the right of the main gun. The coaxial MG is aimed and fired with the same computer fire control system used for the main gun.
  4. (Optional) A second 12.7 mm M2 machine gun can be mounted directly above the main gun in a remote weapons platform as part of the TUSK upgrade kit mentioned below.

The turret is fitted with two six-barreled smoke grenade launchers (USMC M1A1s use an eight-barreled version). These can create a thick smoke that blocks both vision and thermal imaging, and can also be armed with chaff. The engine is also equipped with a smoke generator that is triggered by the driver. When activated, fuel is sprayed on the engine manifold, creating the thick smoke. However, due to change from diesel as a primary fuel to the use of JP-8, this system is disabled on most Abrams today, because JP-8 causes the tanks to catch fire when sprayed on the manifold. The Abrams also has provisions for storing an M16 rifle or M4 carbine inside the turret in case the crew is required to leave the tank under potentially hostile conditions; while the crewmen are supplied with the M9 Beretta pistol as a personal sidearm.

Aiming

The Abrams is equipped with a ballistic fire-control computer that uses data from a variety of sources, including the thermal or daylight Gunner's Primary Sight (GPS), all computing and displaying one of three components of the ballistic solution - lead angle, ammunition type, and range to the target. These three components are determined using a laser rangefinder, crosswind sensor, a pendulum static cant sensor, data on the ammunition type, tank-specific boresight alignment data, ammunition temperature, air temperature, barometric pressure, a muzzle reference sensor (MRS) that determines and compensates for barrel droop at the muzzle due to gravitational pull and barrel heating due to firing or sunlight, and target speed determined by tracking rate tachometers in the Gunner's or Commander's Controls Handles allowing for target speed input into the ballistic solution. The fire-control system uses these data to compute a firing solution for the gunner. The ballistic solution generated ensures a hit percentage greater than 95 percent at nominal ranges. Either the commander or gunner can fire the main gun. Additionally, the Commander's Independent Thermal Viewer (CITV) on the M1A2 can be used to locate targets and pass them on for the gunner to engage while the commander scans for new targets. In the event of a malfunction or damage to the primary sight system, the main and coaxial weapons can be manually aimed using a telescopic scope boresighted to the main gun known as the Gunner's Auxiliary Sight (GAS). The GAS has two interchangeable reticles; one for HEAT and MPAT (MultiPurpose AntiTank) rounds and one for APFSDS and STAFF (Smart Target-Activated Fire and Forget) ammunition. Turret traverse and main gun elevation can be accomplished with manual handles and cranks in the event of a Fire Control System or Hydraulic System failure. The commander's M2 .50 caliber machine gun on the M1 and M1A1 is aimed by a 3x magnification sight incorporated into the Commander's Weapon Station (CWS), while the M1A2 uses either the machine gun's own iron sights, or a remote aiming system such as the CROWS system when used as part of the TUSK (Tank Urban Survival Kit). The loader's M240 machine gun is aimed either with the built-in iron sights or with a thermal scope mounted on the machine gun.

Mobility

The M1 Abrams is powered by a 1500 hp (1119 kW) Honeywell AGT 1500 (originally made by Lycoming) gas turbine, and a six speed (four forward, two reverse) Allison X-1100-3B Hydro-Kinetic Automatic transmission, giving it a governed top speed of 45 mph (72 km/h) on paved roads, and 30 mph (48 km/h) cross-country. With the engine governor removed, speeds of around 60 mph (100 km/h) are possible on an improved surface; however, damage to the drive train (especially to the tracks) and an increased risk of injuries to the crew can occur at speeds above . The tank for all intents and purposes was built around this engine. The tank can be fueled with diesel fuel, kerosene, any grade of motor gasoline, JP-4 jet fuel, or JP-8 jet fuel; the US Army uses JP-8 jet fuel in order to simplify logistics. The Royal Australian Armoured Corps' M1A1 AIM SA uses diesel fuel; it is cheaper and makes practical sense for Australian military logistics.

The gas turbine propulsion system has proven quite reliable in practice and combat, but its high fuel consumption is a serious logistic issue (starting up the turbine alone consumes nearly 10 gallons of fuel). The engine burns more than 1 gallon per mile and 12 gallons per hour when idle. The high speed, high temperature jet blast emitted from the rear of M1 Abrams tanks makes it difficult for the infantry to proceed shadowing the tank in urban combat. The turbine is very quiet when compared to diesel engines of similar power output and produces a significantly different sound from a contemporary diesel tank engine, reducing the audible distance of the sound, thus earning the Abrams the nickname, "whispering death" during its first REFORGER exercise.

Honeywell was developing another gas turbine engine with General Electric for the XM2001 Crusader program that was also to be a replacement for the AGT-1500 engine already in the Abrams tank. The new LV100-5 engine is lighter and smaller (43% fewer parts) with rapid acceleration, quieter running and no visible exhaust. It also features a 33% reduction in fuel consumption (50% less when idle) and near drop-in replacement. The Abrams-Crusader Common Engine Program was shelved when the Crusader program was canceled, however Phase 2 of Army's PROSE (Partnership for Reduced O&S Costs, Engine) program calls for further development of the LV100-5 and replacement of the current AGT-1500 engine. Future US tanks may return to reciprocating engines for propulsion, as 4-stroke diesel engines have proven quite successful in other modern heavy tanks, e.g. the Leopard 2, Challenger 2 and Merkava. The small size, simplicity, power-to-weight ratio, and easy removal/replacement of the turbine powerpack does, however, present significant advantages over any proposed reciprocating replacement.

The Abrams can be carried by a C-5 Galaxy or a C-17 Globemaster III. The limited capacity (two combat-ready in a C-5, one combat-ready tank in a C-17) caused serious logistical problems when deploying the tanks for the First Gulf War, though there was enough time for 1,848 tanks to be transported by ship.

Combat history

As the Abrams entered service in the 1980s, they would operate alongside M60A3 within the United States military, and with other NATO tanks in numerous Cold War exercises. These exercises usually took place in Western Europe, especially West Germany, but also in some other countries like South Korea. During such training, Abrams crews honed their skills for use against the men and equipment of the Soviet Union. However, by 1991 the USSR had collapsed and the Abrams would have its trial by fire in the Middle East.

Operation Desert Storm

The Abrams remained untested in combat until the Gulf War in 1991. A total of 1,848 M1A1s were deployed to Saudi Arabia. The M1A1 was superior to Iraq's Soviet-era T-55 and T-62 tanks, as well as Iraqi assembled Russian T-72s, and locally-produced copies (Asad Babil tank). The T-72s like most Soviet export designs lacked night vision systems and then-modern rangefinders, though they did have some night fighting tanks with older active infrared systems or floodlights—just not the latest starlight scopes and passive infrared scopes as on the Abrams. Only 23 M1A1s were taken out of service in the Gulf and none of these losses resulted in crew deaths from Iraqi fire. Some others took minor combat damage, with little effect on their operational readiness. There were only three tank crew members wounded beyond doubt by enemy action.

The M1A1 was capable of making kills at ranges in excess of 2500 m. This range was crucial in combat against tanks of Soviet design in Desert Storm, as the effective range of the main gun in the Soviet/Iraqi tanks was less than 2000 meters (Iraqi tanks could not fire anti-tank missiles like their Russian counterparts). This meant Abrams tanks could hit Iraqi tanks before the enemy got in range—a decisive advantage in this kind of combat. In friendly fire incidents, the front armor and fore side turret armor survived direct APFSDS hits from other M1A1s. This was not the case for the side armor of the hull and the rear armor of the turret, as both areas were penetrated at least in two occasions by friendly DU ammunition during the Battle of Norfolk.

Nearly all sources claim that no Abrams tank has ever been destroyed as a result of fire from an enemy tank, but some have certainly taken some damage which required extensive repair. There is at least one account, reported in the following Gulf War's DamagedByAssadBabil.gif, of an Abrams being damaged by three kinetic energy piercing rounds. The DoD report indicates that witnesses in the field claimed it was hit by a T-72 Asad Babil. The KE rounds were unable to fully penetrate and stuck in the armor, but because of the external damage it was sent to a maintenance depot. This is the only verified case of an M1A1 put out of action by an Iraqi MBT.

Six other M1A1s were allegedly hit by 125 mm tank fire in the Gulf war official report, but the impacts were largely ineffectual.

On the night of February 26, 1991, four Abrams were disabled in a suspected friendly fire incident by Hellfire missiles fired from AH-64 Apache attack helicopters, with the result of some crew members wounded in action. The tanks were part of TF 1-37, attacking a large section of Tawakalna Republican Guard Division, their numbers being B-23, C-12, D-24 and C-66. However, C-12 was definitively hit and penetrated by a friendly DU shot and there is some evidence that another Iraqi T-72 may have scored a single hit on Summary.gif, besides the alleged Hellfire strike (see Iraqi T-72 article).

Tanks D-24 and C-66 took some casualties as well Only B-23 became a permanent loss. The DoD's damage assessments state that B-23 was the only M1 with signs of a Hellfire missile found nearby.

Also during Operation Desert Storm, three Abrams of the 24 ID were left behind the enemy lines after a swift attack on Talil airfield, south of Nasiriyah, on February 27. One of them was hit by enemy fire, the two other embedded in mud. The tanks were destroyed by U.S. forces in order to prevent any trophy-claim by the Iraqi Army.

List of Abrams disabled or damaged in Desert Storm

No. Identification Number Type of Weapon Place & Date Description of damage Casualties
1. Bumper B-31 TF 1-5 CAV Mine February 19 Ruqi Pocket Tracks/Engine None
2. Unknown number 1st Brigade, 2nd Armored Division Mine February 24 Southern Kuwait Tracks, One M1 tank struck a mine in the breach and lost some road wheels. No one in the tank was injured, and the tank was back in action within a day. None
3. Bumper K-42 2nd Armored Cavalry Regiment Struck by DPICM artillery February 26 73 Easting Loader machine-gun and left fuel cell destroyed 1 WIA
4. Bumper B-66 TF 1-41, 2nd Armored Division(FWD) Three DU kinetic energy rounds, after being hit by an Iraqi RPG February 26 Norfolk line Penetration in the hull, below the turret 1 KIA
2 WIAs
5. Bumper B-22 TF 1-41, 2nd Armored Division(FWD) One DU kinetic energy round February 26 Norfolk line Front slope hit with no internal damage 1 WIA
6. Bumper A-14 TF 1-41, 2nd Armored Division(FWD) One DU kinetic energy round February 26 Norfolk line One hit in the left side of the hull. Extensive damage by fire 3 WIAs
7. Bumper A-31 TF 1-41, 2nd Armored Division(FWD) Splinters of one DU kinetic energy penetrator February 26 Norfolk line Hit in the rear left hull None
8. Bumper A-33 TF 1-41, 2nd Armored Division(FWD) Two DU rounds, after being hit by TOW missile February 26 Norfolk line Double penetration of the hull 3 WIAs
9. Bumper D-24 TF 1-37, 1st Armored Division Small caliber shaped charge February 26 Assault on Tawakalna Division Impact on NBC exhausts, compartment penetrated 2 WIAs
10. Bumper B-23 TF 1-37, 1st Armored Division Large caliber shaped charge, then hit by an unknown round, likely a KE (non-DU) February 26 Assault on Tawakalna Division Two hits, one on the rear grills, another penetrated both sides of the hull. Catastrophic damage by fire 1 WIA
11. Bumper C-12 TF 1-37, 1st Armored Division One DU kinetic energy penetrator, then hit by anti-tank missile February 26 Assault on Tawakalna Division KE round achieved a double penetration of the hull. The anti-tank missile set the storage area of the turret on fire None
12. Bumper C-66 TF 1-37, 1st Armored Division Two small shaped charges February 26 Assault on Tawakalna Division Small penetration of the left rear side of the hull. Impact on the turret defeated by armor 3 WIAs
13. Bumper C-12 TF 4-8th CAV, 3rd Armored Division 73 mm shell
from a BMP-1
February 26 Assault on Tawakalna Division Minor damage to sponson box and .50 machine-gun 1 WIA
14. Bumper B-24 TF 4-8th CAV, 3rd Armored Division Enemy indirect fire February 26 Assault on Tawakalna Division Damaged to sponson box and duffle bags None
15. Bumper C-24 TF 4-8th CAV, 3rd Armored Division Friendly DPICM February 26 Assault on Tawakalna Division Storage area shredded by shrapnel Main gun punctured None
16. Unknown number 197th Brigade, 24 Infantry Division Crippled by enemy fire, then destroyed by DU rounds February 27 Assault on Tallil airfield Ammunition blown-up None
17. Unknown number 197th Brigade, 24 Infantry Division Stuck in mud, then destroyed by DU rounds February 27 Assault on Tallil airfield Ammunition blown-up None
18. Unknown number 197th Brigade, 24 Infantry Division Stuck in mud, then destroyed by DU rounds February 27 Assault on Tallil airfield Ammunition blown-up None
19. Bumper HQ66 Commander tank, TF 4-64 Armor, 24 Infantry Division Two conventional KE or HEAT rounds from a 100 mm gun February 27 South-west of Basra 120 mm gunner's primary sight (GPS) damaged and fuel-cell punctured. Sight replaced next morning. Tank continued in combat. None
20. Unknown number Turret number:5840U

Hull number:D10060

Three conventional KE rounds from an Iraqi T-72 Unknown date/location Two partial penetrations on the rear turret right side (possible fire in the storage area). Cosmetic damage on the turret front DU left armor plate. None
21. Bumper A-22 2nd Platoon, A Company, TF 4-64, 24 Infantry Division Secondary explosions from an Iraqi T-72 March 2 Rumeilah Oilfields Storage area devastated by fire. Ammunition blown-up. 1 WIA

The Iraq war

Further combat was seen during 2003 when US forces invaded Iraq and deposed the Iraqi leader Saddam Hussein. As of March 2005, approximately 80 Abrams tanks were forced out of action by enemy attacks. Nevertheless, the campaign saw very similar performance from the tank with no Abrams crew member being lost to hostile fire during the invasion of Iraq, although several tank crew members were later killed by snipers and roadside bombs during the occupation that followed. Abandoned Abrams were purposely destroyed by friendly fire to prevent recovery of vehicle or technology. Damages by 25 mm AP-DU, anti-armor RPG fire and 12.7 mm rounds was encountered. But on no occasion anti-tank guided weapons or anti-tank mines struck the US MBTs.

The most lopsided achievement of the M1A2s was the destruction of seven T-72 Lion of Babylon tanks in a point-blank skirmish (less than 50 yards) near Mahmoudiyah, about south of Baghdad, with no losses for the American side. However, on October 29, 2003, two soldiers were killed and a third wounded when their tank was disabled by an anti-tank mine, which was combined with other explosives (500 kg, including several 155 mm rounds) to increase its effect. The massive explosion beneath the tank knocked off the turret. This marked the first time deaths resulted from a hostile-fire assault on the M1 tank from enemy forces. Following lessons learned in Desert Storm, the Abrams and many other US combat vehicles used in the conflict were fitted with Combat Identification Panels to reduce friendly fire incidents. These were fitted on the sides and rear of the turret, with flat panels equipped with a four-cornered 'box' image on either side of the turret front (the latter of which can be seen in the above image, similar flat panels also being employed on British Challenger 2 tanks serving in the conflict). In addition to the Abrams' already-formidable armament, some crews were also issued M136 AT4 shoulder-fired anti-tank weapons under the assumption that they might have to engage heavy armor in tight urban areas where the main gun couldn't be brought to bear. Some Abrams were also fitted with a secondary storage bin on the back of the existing bustle rack on the rear of the turret referred to as a bustle rack extension to enable the crew to carry more supplies and personal belongings.

During the major combat operations in Iraq, Abrams crew members were lost when one tank of the US Army's 3rd Infantry Division, and US Marine Corps troops, drove onto a bridge. The bridge collapsed, dropping the tank into the Euphrates River, where four Marines drowned.

During an early attack on Baghdad, one M1A1 was disabled by a recoilless rifle round that had penetrated the rear engine housing, and punctured a hole in the right rear fuel cell, causing fuel to leak onto the hot turbine engine. After repeated attempts to extinguish the fire, the decision was made to destroy or remove any sensitive equipment. Oil and .50 caliber rounds were scattered in the interior, the ammunition doors were opened and several thermite grenades ignited inside. Another M1 then fired a HEAT round in order to ensure the destruction of the disabled tank. The tank was completely disabled but still intact. Later, an AGM-65 Maverick and two AGM-114 Hellfire missiles were fired into the tank to finish its destruction. Remarkably, the tank still appeared to be intact from the exterior.

On November 27, 2004 an Abrams tank was badly damaged from the detonation of an extremely powerful improvised explosive device (IED). The IED consisted of three M109A6 155 mm shells, with a total explosive weight of 34.5 kg, that detonated next to the tank. The tank's driver received lethal injuries from shrapnel. The other three crew members were able to escape.

On December 25, 2005 another U.S. Army M1A1 was disabled by an explosively formed penetrator IED. The IED penetrated through a road wheel, and hit the fuel tank, which left the tank burning near central Baghdad. One crew member, SPC Sergio Gudino, died in the attack.

On June 4, 2006 two of the four soldiers in an Abrams crew died in Baghdad, when an IED detonated near their M1A2.

Some Abrams were disabled by Iraqi infantrymen in ambushes employing short-range antitank rockets, such as the Russian RPG-7, during the 2003 invasion. Although the RPG-7 is unable to penetrate the front and sides, the rear and top are vulnerable to this weapon. Frequently the rockets were fired at the tank tracks. Another was put out of action in an incident when fuel stowed in an external rack was struck by heavy machine gun rounds. This started a fire that spread to the engine.

There have also been a number of Abrams crewmen killed by sniper fire during times when they were exposed through the turret hatches of their tanks. Some of these attacks were filmed by insurgents for propaganda purposes and spread via the Internet. One of these videos shows a large IED detonating beneath an Abrams and nearly flipping the vehicle, though the tank landed back on its treads and appeared to have suffered no serious damage as it was still mobile and traversing the turret following the attack.

Variants and upgrades

  • XM1 Experimental model. Nine test-beds were produced in 1978.
  • M1 First production variant. Production began in 1979 and continued to 1985 (3,273 build for US).
    • M1IP (Improvement Production). Produced briefly in 1984 before the M1A1, contained upgrades and reconfigurations.
  • M1A1 Production started in 1986 and continued to 1992 (4,976 build for US, 221 for USMC, 755 for Egypt, 59 M1A1 AIM SA sold to Australia).
    • M1A1HC (Heavy Common) added new depleted uranium armor mesh, pressurized NBC system, rear bustle rack for improved stowage of supplies and crew belongings, and M256 120 mm smoothbore cannon.
    • M1A1-D (Digital) A digital upgrade for the M1A1HC, to keep up with M1A2 SEP.
      • M1A1-AIM (Abrams Integrated Management) A program whereby older units are reconditioned to zero hour conditions; and the tank is improved by adding Forward-Looking Infra-Red (FLIR) and Far Target Locate sensors, a tank-infantry phone, communications gear, including FBCB2 and Blue Force Tracking, to aid in crew situational awareness, and a thermal sight for the .50 caliber machine gun. General Dynamics has been awarded contracts by the US Army to supply this variant. Additionally, 59 M1A1 AIM SA have been sold to Australia.
    • M1A1 KVT (Krasnovian Variant Tank) M1A1's that have been visually modified to resemble Soviet-made tanks for use at the National Training Center, fitted with MILES gear and a Hoffman device.
  • M1A2 (Baseline) Production began in 1992 (77 build for US and more than 600 M1s upgraded to M1A2, 315 for Saudi Arabia, 218 for Kuwait). The M1A2 offers the tank commander an independent thermal sight and ability to, in rapid sequence, shoot at two targets without the need to acquire each one sequentially.
  • M1A2 SEP (System Enhancement Package) Also with upgraded 3rd generation depleted uranium encased armor with graphite coating (240 new build, 300 M1A2s upgraded to M1A2SEP for the USA, 250 for Egypt in 2 Egyptian co-production batches of 125 each).
  • M1 Grizzly Engineer Vehicle
  • M1 Panther II Remote Controlled Mine Clearing Vehicle
  • M104 Wolverine Heavy Assault Bridge
  • M1 Panther II Mine Clearing Blade/Roller System.
  • M1 Assault Breacher Vehicle.
  • M1 Armored Recovery Vehicle. Only a prototype produced.

Specifications of variants

M1 M1IP M1A1 M1A2 M1A2 SEP
Length 32.04 ft (9.77 m)
Width
Height 7.79 ft (2.37 m) 8.0 ft (2.44 m)
Top speed 45 mph (72 km/h) 41.5 mph (67 km/h) 42 mph (68 km/h)
Range 310 mi (498 km)   288 mi (465 km) 243 mi (391 km)  
Weight 61.4 tons (55.7 tonnes) 62.8 tons (57.0 tonnes) 67.6 tons (61.3 tonnes) 68.4 tons (62.1 tonnes) 69.5 tons (63.0 tonnes)
Main armament 105 mm M68 rifled 120 mm M256 smoothbore
Crew 4 (commander, gunner, loader, driver)

Note: All of the above produce a power of 1500 hp (1119 kW).

Tank Urban Survival Kit

The Tank Urban Survival Kit, or TUSK, is a series of improvements to the M1 Abrams intended to improve fighting ability in urban environments. Historically, urban and other close battlefields have been the worst place for tanks to fight—a tank's front armor is much stronger than that on the sides, top, or rear, and in an urban environment, attacks can come from any direction, and attackers can get close enough to reliably hit weak points in the tank's armor, or get sufficient elevation to hit the top armor square on.

Armor upgrades include reactive armor on the sides of the tank and slat armor (similar to that on the Stryker) on the rear to protect against rocket-propelled grenades and other shaped charge warheads.

A Transparent Armor Gun Shield and a thermal sight system are added to the loader's top-mounted M240B 7.62 mm machine gun, and a Kongsberg Gruppen Remote Weapon Turret carrying a .50 caliber machine gun (again similar to that used on the Stryker) is in place of the tank commander's original .50 caliber machine gun mount, wherein the commander had to expose himself to fire the weapon manually. An exterior telephone allows supporting infantry to communicate with the tank commander.

The TUSK system is a field-installable kit that allows tanks to be upgraded without needing to be recalled to a maintenance depot.

While the reactive armor may not be needed in most situations in maneuver warfare, items like the rear slat armor, loader's gun shield, infantry phone (which has already seen use on Marine Corps M1A1s as early as 2003), and Kongsberg Remote Weapons Station for the .50 caliber machine gun will be added to the entire M1A2 fleet over time.

On August 29, 2006 General Dynamics Land Systems received a US Army order for 505 Tank Urban Survivability Kits (TUSK) for Abrams main battle tanks supporting operations in Iraq, under a US$45 million contract. The add-on kit will be provided for M1A1 and M1A2-series tanks to enhance crew survivability in urban environments. The kit ordered by the Army consists of a Loader's Armor Gun Shield (LAGS), a Tank Infantry Phone (TIP), Abrams Reactive Armor Tiles (ARAT), a Remote Thermal Sight (RTS) and a Power Distribution Box (PDB). Deliveries are expected to be complete by April 2009.

Under a separate order, the US Army awarded General Dynamics Armament and Technical Products (GDATP) US$30 million to produce reactive armor kits to equip M1A2. The total contract value could reach $59 million if all contract options are exercised. The reactive tiles for the M1 will be locally produced at GDATP's Burlington Technology Center. Tiles will be produced at the company's reactive armor facility in Stone County Operations, McHenry, Miss. On December 8 2006 the U.S. Army added Counter Improvised Explosive Device enhancements to the M1A1 and M1A2 TUSK, awarding GDLS U.S. $11.3 million, part of the $59 million package mentioned above. In December GDLS also received an order amounting about 40% of a US$48 million order for loader's thermal weapon sights being part of the TUSK system improvements for the M1A1 and M1A2 Abrams Tanks.

M1 Abrams camouflage

Unlike older US military vehicles from World War II through Vietnam, which used a scheme of dark brownish green with large white stars, prototypes and early production M1 (105mm gun) & M-1IP models used the flat medium green paint known as "olive drab." Some units painted their M1s with the older MERDC paint scheme but the turn-in requirements for these tanks required repainting them to solid green. Therefore, even though a large number of the base model M1s were camouflaged in the field, few or none exist today.

M1A1s (120mm gun) came from the factory with the NATO 3 color camouflage Black/Med-Green/Dark-Brown CARC paint jobs. Today M1A1s are given the NATO three color paint job during rebuilds. M1s and M1A1s deployed to Desert Storm were hastily painted desert tan. Some, but not all, of these tanks were re-painted to their "authorized" paint scheme. M1A2s built for Middle Eastern countries were painted in desert tan.

Some M1 series tanks are being painted desert tan for service in Iraq and some are not. Replacement parts (roadwheels, armor skirt panels, drive sprockets, etc.) are painted overall green, which can sometimes lead to vehicles with a patchwork of green and desert tan parts.

Operators

  • - 59 M1A1 AIM SA tanks were bought from the United States in 2006, to replace the Leopard AS1 in 2007.
  • - 1005 (755 M1A1 to be brought to M1A2 SEP standard + 250 M1A2 SEP) M1A1
  • - 218 M1A2
  • - 315 M1A2 - 73 M1A1 - 388 Total
  • - Over 9,000 built, including foreign sales above
    • 1174 M1A2 (Army inventory)
    • 4393 M1A1 (Army inventory)
    • 403 M1A1 (USMC inventory)
    • Remaining number of M1 (Army, M1 in service according to the US Army Factfile but probably only used by National Guard).

On July 31/08, the US Defense Security Cooperation Agency announced [PDF] Iraq’s formal request to buy M1 Abrams tanks, well as the associated vehicles, equipment and services required to keep these tanks in the field. It is likely that the tanks themselves will be transferred from US stocks, but this has not been verified. With this purchase, Iraq will become the 4th M1 Abrams operator in the region.

See also

Comparable Vehicles

Notes

References

External links

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