M1 Abrams Main Battle Tank

M1 Abrams Main Battle Tank

The M1 Abrams Main Battle Tank (MBT) is the namesake of the late General Creighton W. Abrams, former Army Chief of Staff and commander of the 37th Armored Battalion. It is the backbone of the armored forces of the United States military, and several of US allies as well. The purpose of this vehicle is to provide mobile firepower for armored formations of sufficient capability to successfully close with and destroy any opposing armored fighting vehicle in the world, while providing protection for it's crew in any conceivable combat environment. It is capable of engaging the enemy in any weather, day or night on the multi-dimensional, non-linear battlefield using its firepower, manuever, and shock effect. The Abrams Tank System synchronizes its high tempo, distributed manuever via its digitized situational awareness and the fusion of onboard and remote battlefield sensors.

The Army made the decision for a new tank series in 1972 and awarded developmental contracts in 1973. The first prototypes of the M1, known as the XM1, reached the testing stage in 1976, and the tank began to arrive in battalions in February 1980. The M1 enjoyed a low silhouette and a very high speed, thanks to an unfortunately voracious gas turbine engine. Chobham spaced armor (ceramic blocks set in resin between layers of conventional armor) resolved the problem of protection versus mobility. A sophisticated fire control system provided main gun stabilization for shooting on the move and a precise laser range finder, thermal-imaging night sights, and a digital ballistic computer solved the gunnery problem, thus maximizing the utility of the 105-mm. main gun.

The M1 has a very angular appearance, reflecting the modular nature of its armor components, with the turret mounted centrally on the hull.

The M1 has a crew of four. The driver sits centered in the hull and forward of the turret, while the loader, gunner and tank commander occupy the turret, with the loader situated to the left of the main gun and the gunner and tank commander sitting in tandem on the right side. The driver's hatch has three periscope vision blocks which provide for forward vision. The center vision block may be removed and replaced with an AN/TVS-2 low-light periscope.

The engine is mounted in the rear of the vehicle with the exhaust coming out from a louvered grill centrally mounted in the rear of the hull. The M1 utilizes a torsion bar suspension with seven pairs of cast aluminum road wheels and two return rollers. The drive sprocket is to the rear, an idler compensation wheel is located forward, and there is a gap between the first and second pair of road wheels. The M1 has armored skirts running the full length of the track. M1 track is made up of vulcanized rubber blocks (M156 variety) or removable rubber pads (M158.)

The turret is also angular in appearance, with the main gun mounted in an exposed mantlet in the center of the turret face. The M68 rifled cannon is equipped with a metal thermal shroud, a bore gas evacuator located two-thirds of the way down on the barrel, and is equipped with a Muzzle Reference System collimator on the muzzle itself. The M240 coaxial (COAX) machine gun is located to the right of the main gun, with the flash tube extending through the main gun mantlet. The Gunner's Auxiliary Sight (GAS) aperture is located below the COAX flash tube on the right side of the main gun.

The M1 has two turret access hatches, mounted side by side, in the middle of the turret roof. The loader's hatch, located on the left side, is equipped with a pintle mounted M240 7.62mm machine gun. The hatch itself is equipped with a single vision periscope on a rotating base. When not in use, the drivers AN/TVS-2 sight may be used in the loader's hatch vision block. The tank commander's hatch is ringed by vision periscopes and the Commander's Weapon Station cupola is equipped with an M2 HB caliber .50 machine gun. The M2 may be fired while the commander is "buttoned up" but the commander must be exposed to reload the weapon. The CWS can be reconfigured to fire an M240 as a replacement weapon.

The Gunner's Primary Sight (GPS) is located forward of the commander's cupola. The GPS is housed in an armored box with hinged doors shielding the optics when not in use. The GPS is divided into two halves; a clear glass window for normal daylight viewing and an IR transparent Germanium coated window for the thermal imaging sight. The Laser Range Finder (LRF) is fired through the daylight window.

There are individual sponson boxes located on either side of the turret for equipment storage. These boxes are approximately three feet (1m) long and are bracketed by a three-rail cargo rack which runs the length of the turret side. The smoke grenade launchers are located on either side of the turret, forward of the turret sponson boxes. There are mounting points for two radio antennae, one on either side of the turret rear, and the cross wind sensor is mounted upright in the center of the turret rear. A cargo bustle rack is mounted on the rear of the turret and runs the length of the turret rear (in early production M1s this rack was omitted and a fabric cargo net mounted in it's place. An Auxiliary Power Unit (APU) may be mounted in the turret bustle rack or on the rear of the hull.

Assembly plants had manufactured more than 2,300 of the 62-ton M1 tank by January 1985, when the new version, the MlA1, was approved for full production. The MlA1 had improved armor and a 120mm. main gun that had increased range and kill probability. By the summer of 1990 several variations of the M1 had replaced the M60 in the active force and in a number of Army Reserve and National Guard battalions. Tankers had trained with the Abrams long enough to have confidence in it. In fact, many believed it was the first American tank since World War II that was qualitatively superior to Soviet models.

Production of M1A1 tanks for the US Army is complete. Over 8,800 M1 and M1A1 tanks have been produced for the US Army and Marine Corps, and the armies of Egypt, Saudi Arabia and Kuwait. Production of new M1A1 and M1A2 Abrams tanks is in its final phase for Foreign Military Sales. Egypt has purchased 777 M1A1 tank kits. The Kingdom of Saudi Arabia purchased and fielded 315 M1A2 Abrams tanks in the Royal Saudi Land Forces. The Government of Kuwait purchased and fielded 218 M1A2 Abrams tanks in the Kuwaiti Land Forces. All of these nations are considering additional orders or configuration upgrades.

Three versions of the Abrams tank are currently in service the original M1 model, dating from the early 1980s, and two newer versions, designated M1A1 and M1A2. The M1A1 series, produced from 1985 through 1993, replaced the M1’s 105mm main gun with a 120mm gun and incorporated numerous other enhancements, including an improved suspension, a new turret, increased armor protection, and a nuclear-chemical-biological protection system. The newer M1A2 series includes all of the M1A1 features plus a commander’s independent thermal viewer, an independent commander’s weapon station, position navigation equipment, and a digital data bus and radio interface unit providing a common picture among M1A2s on the battlefield.

In lieu of new production, the Army is upgrading approximately 1,000 older M1 tanks to the M1A2 configuration. The Army also initiated a modification program for the M1A2 to enhance its digital command and control capabilities and to add the second generation forward looking infrared (FLIR) sights to improve the tank's fightability and lethality during limited visibility. This system enhancement program will be fielded in the 2000 time frame concurrently with the M2A3 Bradley and other advanced digital systems. The initial M1A2 fielding to the First Calvary Division, Ft. Hood, TX, is underway. The Army will continue to field M1A2s to the CONUS contingency corps and other first to fight units.

	M1/IPM1		M1A1		M1A2
Length:	32.04 FT		32.25 FT		32.25 FT
Width:	12.0 FT		12.0 FT		12.0 FT
Height:	7.79 FT		8.0 FT		8.0 FT
Top Speed:	45.0 MPH		41.5 MPH		41.5 MPH
Weight:	60 TONS		67.6 TONS		68.7 TONS
Armament:	105 MM		120 MM		120 MM
Crew:	4		4		4

The M1 series tank is equipped with a 1500 horsepower Lycoming Textron gas turbine engine coupled to an Allison hydrokenetic transmission with four forward and two reverse gears. It's tactical crusing range is approximately 275 miles. Despite it's weight, the M1 can attain a top speed of nearly 45 miles per hour. The main armament is a 120mm smooth bore cannon, which replaced the 105mm gun on the initial M1 version. It has day/night fire on the move capability which is provided by a laser range finder, thermal imaging night sight, optical day sight, and a digital ballistic computer. Both the fuel and ammunition are compartmented to enhance survivability. The hull and turret are protected by advanced armor similar to the Chobam armor developed by the British Ministry of Defense. When required, the Abrams may be fitted with "reactive armor" to thwart armor-defeating munitions.

The M1 Abrams tank, weathered considerable criticism and, in fact, began from the failure of a preceding tank program. The standard tanks in the Army inventory had been various models of the M48 and M60, both surpassed in some respects by new Soviet equipment. The XM803 was the successor to an abortive joint American-German Main Battle Tank-70 project and was intended to modernize the armored force. Concerned about expense, Congress withdrew funding for the XM803 in December 1971, thereby canceling the program, but agreed to leave the remaining surplus of $20 million in Army hands to continue conceptual studies.

For a time, designers considered arming tanks with missiles for long-range engagements. This innovation worked only moderately well in the M60A2 main battle tank and the M551 Sheridan armored reconnaissance vehicle, both of which were armed with the MGM51 Shillelagh gun launcher system. In the late 1960s, however, tank guns were rejuvenated by new technical developments that included a fin-stabilized, very high velocity projectile that used long-rod kinetic energy penetrators. Attention centered on 105-mm. and 120-mm. guns as the main armament of any new tank.

Armored protection was also an issue of tank modernization. The proliferation of antitank missiles that could be launched by dismounted infantry and mounted on helicopters and on all classes of vehicles demonstrated the need for considerable improvement. At the same time, weight was an important consideration because the speed and agility of the tank would be important determinants of its tactical utility. No less important was crew survivability; even if the tank were damaged in battle, it was important that a trained tank crew have a reasonable chance of surviving to man a new vehicle.

The Army made the decision for a new tank series in 1972 and awarded developmental contracts in 1973. The first prototypes of the M1, known as the XM1, reached the testing stage in 1976, and the tank began to arrive in battalions in February 1980. The M1 enjoyed a low silhouette and a very high speed, thanks to an unfortunately voracious gas turbine engine. Chobham spaced armor (ceramic blocks set in resin between layers of conventional armor) resolved the problem of protection versus mobility. A sophisticated fire control system provided main gun stabilization for shooting on the move and a precise laser range finder, thermal-imaging night sights, and a digital ballistic computer solved the gunnery problem, thus maximizing the utility of the 105-mm. main gun.

Although fielded in 1980, the Abrams remained untested for over 10 years. When Iraq invaded Kuwait in August 1990, there were concerns that the Abrams would fall victim to the sand and long months of continuous operation without the luxury of peacetime maintenance facilities. There were also doubts about the combat survivability of the extensive turret electronics. Immediately following President Bush's decision to commit US forces to the Gulf region in defense of Kuwait and Saudi Arabia, American armored units began the difficult process of relocating to the threatened area. Due to the shear size and weight of the Abrams, the C-5 Galaxy, the largest cargo aircraft in the US Air Force inventory, was only able to handle one tank at a time. This meant that nearly all of the Abrams tanks deployed in the Gulf War were shipped by cargo ship. Although slow in coming, the arrival of the Abrams was much welcomed by Allied forces, as it is capable of defeating any tank in the Iraqi inventory.

The Iraqi Army had a considerable array of tanks, mostly purchased from the former Soviet Union. Chief among these were about 500 T-72's. These modern Soviet tanks were armed with an excellent 125mm smoothbore weapon and had many of the same advanced features found on the Abrams. Despite it's advanced design, the T-72 proved to be inferior to the M1A1's deployed during the Gulf War, and compared more closely with the older M60A3 tanks used there by the US Marine Corps. In addition, Iraq had a number of earlier Soviet models: perhaps as many as 1,600 T-62 and about 700 T-54, both of which were developed in the 1960's. These tanks were widely regarded as clearly inferior to the Abrams, but were expected to be highly reliable mechanically. The Gulf War provided military tacticians with an opportunity to evaluate developments in tank design that had not been available since World War II.

In his book "Desert Victory - The War for Kuwait", author Norman Friedman writes that "The U.S. Army in Saudi Arabia probably had about 1,900 M1A1 tanks. Its ability to fire reliably when moving at speed over rough ground (because of the stabilized gun mount) gave it a capability that proved valuable in the Gulf. The Abrams tank also has… vision devices that proved effective not only at night, but also in the dust and smoke of Kuwaiti daytime. On average, an Abrams outranged an Iraqi tank by about 1,000 meters." The actual numbers of Abrams M1 and M1A1 tanks deployed to the Gulf War (according to official DOD sources) are as follows: A total of 1,848 M1A1 and M1A1 "Heavy Armor" (or HA) tanks were deployed between the US Army and Marine Corp (who fielded 16 M1A1's and 60 M1A1(HA) tanks).

As the Gulf War shifted pace from Operation Desert Shield to Operation Desert Storm, and the preparatory bombardment lifted, U.S. Abrams tanks spearheaded the attack on Iraqi fortifications and engaged enemy tanks whenever and wherever possible. Just as they had done in the Iran-Iraq War, the Iraqi Army used it's tanks as fixed anti-tank and artillery pieces, digging them into the ground to reduce target signature. However, this also prevented their quick movement and Allied air power smashed nearly 50% of Iraq's tank threat before Allied armor had moved across the border. After that the Abrams tanks quickly destroyed a number of Iraqi tanks that did manage to go mobile.

The Abrams' thermal sights were unhampered by the clouds of thick black smoke over the battlefield that were the result of burning Kuwaiti oil wells. In fact many Gunners relied on their "night" sights in full daylight. Such was not the case with the sights in the Iraqi tanks, which were being hit from units they could not even see. Concerns about the M1A1's range were eliminated by a massive resupply operation that will be studied for years as a model of tactical efficiency.

During the Gulf War only 18 Abrams tanks were taken out of service due to battle damage: nine were permanent losses, and another nine suffered repairable damage, mostly from mines. Not a single Abrams crewman was lost in the conflict. There were few reports of mechanical failure. US armor commanders maintained an unprecedented 90% operational readiness for their Abrams Main Battle Tanks.