The M1A1 is the first major block improvement to the M1 ABRAMS Tank System and
provides a significant improvement to the Army's offensive ground combat power as displayed during Operation Desert Storm. This block upgrade includes the 120mm M256 cannon, improved fire control
system, and NBC overpressure system, and improved suspension.
These improvements give the M1A1 greater shoot-on-the move capabilities and an increased first round probability against advanced enemy armor. A new configuration is currently under development that will incorporate the Force XXI Battle Command Brigade and Below (FBCB2) computer and software and a far target designate capability. The M1A1 is fielded throughout the US Army, the US Marine Corps, and is being coproduced for the Government of Egypt.
This tank significantly increases the capabilities of the Fleet Marine Forces across the full spectrum of conflict in the near and midterm. The M1A1 Tank, in addition to the improved armor, 120mm smoothbore gun and the NBC overpressure system, has a Deep Water Fording Kit (DWFK), a Position Location Reporting Systems (PLRS), enhanced ship tiedowns, Digital Electronic Control Unit (DECU) (which allows significant fuel savings),and Battlefield Override.
The main weapon of the M1A1 is the M256 120mm smoothbore cannon, designed by the Rheinmetall Corporation of Germany. Engagement ranges approaching 4000 meters were successfully demonstrated during Operation Desert Storm. The primary armor-defeating ammunition of this weapon is the armor-piercing, fin-stabilized, discarding sabot (APDS-FS) round, which features a depleted uranium penetrators. Depleted uranium has density two and a half times greater than steel and provides high penetration characteristics. Several other types of ammunition are available as well. It is reliable, deadly accurate and has a "hit/kill ratio" that equals or surpasses any main battle tank armament in the world.
As with virtually every tank every fielded by the US, the familiar .50 caliber Browning M2 Heavy Barrel machine gun - the "Ma Duce" - is located in a powered mount at the Commander's station and is equipped with a x3 magnification sight. The Loader is provided with a 7.62mm M240 machine gun, and another M240 is mounted in-line with the main gun of the tank ("coaxially"). It is in a fixed mount and is aimed with the main gun to suppress enemy ground troops.
The layout of the Abrams follows classic tank design and accommodates a crew of four: Commander, Gunner, Loader and Driver. The Commander and Gunner are seated on the right side of the turret. The Loader is seated on the left side of the turret, and the Driver is seated at the center front of the hull.
The Commander's station is equipped with six periscopes which provide all round 360 degree view. The Independent Thermal Viewer (ITV) from Texas Instruments provides him with independent, stabilized day and night vision with a 360 degree view, automatic sector scanning, automatic target cueing of the Gunner's sight with no need for verbal communication, and a complete back-up fire control system - the Commander is capable of firing the main gun independent of the Gunner.
The Gunner's Primary Sight-Line of Sight (GPS-LOS), was developed by the Electro-Optical Systems Division of Hughes Aircraft Company. The night vision Thermal Imaging System (TIS), also from Hughes, creates an image based on the differences of heat radiated by objects in the field of view. The thermal image is displayed in the eyepiece of the Gunner's sight together with the range measurement to within 10 meters of accuracy, from a Hughes laser range finder, which is integrated into all of the fire control systems.
The Abrams also has an onboard digital fire control computer. Range data from the laser rangefinder is transferred directly to the fire control computer, which automatically calculates the fire control solution. The data includes 1) the lead angle measurement, 2) the bend of the gun measured by the muzzle reference system of the main armament, 3) wind velocity measurement from a wind sensor on the roof of the turret and 4) the data from a pendulum static cant sensor located at the center of the turret roof. The Gunner or Commander manually inputs the data on the ammunition type and temperature, and the barometric pressure and the weapon is prepared for engagement.
The Loader's station is located on the left side of the turret and has no special fire control equipment.
The Driver's station is located at the center front of the hull. The Driver is in a semi-reclined position when his hatch is closed, as it must be whenever the vehicle is in operation. His station is equipped with a standard array of gages and monitors reflecting the condition of vehicle fluid levels, batteries and electrical equipment.
The Driver has either three observation periscopes or two periscopes on either side and a central image intensifying ("Starlight") periscope for night vision. The periscopes provide 120 degrees field of view. The Driver's night vision equipment enables the tank to maneuver at normal daytime driving speeds in darkness and in poor visibility conditions such as in the dust and smoke encountered on the battlefield.
The turret is fitted with two six-barreled M250 smoke grenade launchers, one on each side of the main gun.
The standard smoke grenade contains a phosphors compound that masks thermal signature of the vehicle to the enemy. A smoke screen can also be laid by an engine operated system.
An improvement program will eventually upgrade all M1A1 tanks with steel encased depleted uranium armor, which has a density at least two-and-a-half times greater than steel. The depleted uranium armor will raise the total weight of the Abrams tank to 65 tons, but offers vastly improved protection in the bargain.
The Abrams has been using Depleted Uranium (DU) armor since 1988. In 1996, a design change to the armor package was made by the Army and cut-in to production by General Dynamics Land Systems (GDLS) via Change Request XMPP-2083 in Oct 96 and effective with Job #1 M1A2 Phase II AUT. The use of DU armor is a primary feature that distinguishes the Abrams tank from numerous other commonly accepted equipment employed by the military and industry.
The current use of the depleted uranium (DU) armor package on the M1 Abrams Main Battle Tank (MBT) Heavy Armor System has been re-evaluated to determine whether the environmental impacts of its continued use remain insignificant, taking into consideration the current use of the tank and the Nuclear Regulatory Commission's (NRC's) reduction in allowable radiation exposure from 500 mrem/year to 100 mrem/year for tank and maintenance crews (individual members of the public).
As in already-fielded weapon system, M1 MBTs have been in production and in the field since the early 1980s. During that time, many technical, environmental and health assessments have been completed. These documents have addressed and minimized environmental impacts.
The stowage for the main armament ammunition is in armored ammunition boxes behind sliding armor doors. Armor bulkheads separate the crew compartment from the fuel tanks. The tank is equipped with an automatic Halon fire extinguishing system. This system automatically activates within 2 milliseconds of either a flash or a fire within the various compartments of the vehicle. The top panels of the tank are designed to blow outwards in the event of penetration by a HEAT projectile.
Nuclear, Biological and Chemical (NBC) warfare protection is provided by an overpressure clean-air conditioning air system, a radiological warning system, and a chemical agent detector. The crew are individually equipped with protective suits and masks.
The Marine Corps has fielded the M1A1 Common Tank to replace the aging M60A1 Rise/Passive tank. The M60 has reached the end of its service life and lacks the capability to survive and to defeat the threats expected to be encountered on the modern battlefield. During Operation Desert Shield/Storm, the Marine Corps borrowed 60 M1A1s (called the M1A1 Heavy Armor) from the US Army.
There were also 16 Marine Corps M1A1 Tanks delivered on an accelerated schedule for employment during the operation. This total of 76 M1A1 tanks was employed by 2d Tank Battalion and elements of 4th Tank Battalion. The M1A1 tanks saw immediate action during the I Marine Expeditionary Force (IMEF) drive through the burning Kuwaiti oil fields. All loaned tanks were returned to the US Army after Desert Storm.
Due to unique Marine Corps amphibious requirements, and the need for both supportability and interoperability between the Marine Corps and the US Army, the two services agreed to jointly produce the M1A1 Main Battle Tank. The M1A1 MBT has the capability to conduct operations ashore. It is compatible with all US Navy amphibious ships and craft (to include the LCAC) and Maritime Prepositioning Ships (MPS). The USMC completed fielding of all tanks, to include active, reserve, MPS, and depot maintenance float (DMF) during FY 96.
n 1995 the 26th MEU became the first amphibiously deployed unit to carry the M1A1. This added some complication to the logistics of the unit due to the tank's weight. Topping the scales at over 68 tons the vehicle requires special care during amphibious operations. One tank can be carried at a time on an Air Cushioned Landing Craft (LCAC), two on a Landing Craft Utility (LCU), but only during fairly calm seas. For operations with the Marine Corps, tanks have been equipped with special fording systems. These modifications include extended air intake and exhaust tubes that allow the vehicles to cross rivers and shallow waters such as the surf zones that Marines operate in.
M1A1 Abrams Tank Firepower Enhancement Program (FEP)
The M1A1 Abrams Tank Firepower Enhancement Program (FEP), a Marine Corps Systems Command initiative, is intended to increase the all weather, day and night target acquisition and engagement ranges and provide a far target location capability for the M1A1 Tank. The FEP system will include a scope of work that entails a suite of upgrades for the M1A1 Tank. These upgrades include a second-generation thermal sight and a north finding/target locating capability. The system will increase the tank crew's ability to detect, recognize, identify and accurately locate targets.
In the Fall of 2004, Marine Corps Systems Command signed the Milestone C Decision for full rate production of the M1A1 Tank Firepower Enhancement Program (FEP). Installed on the M1A1 Tank, the FEP will bring the MAGTF all weather, thermal, day or night, rapid and accurate target engagement capability. Additionally, it will couple extended engagement ranges with a new Far Target Locate (FTL) function. Overall, the FEP greatly increases tank lethality and extends the Marine Corps overmatch of current and expected threat systems beyond 2018.
The Firepower Enhancement Program is a suite of upgrades for the M1A1 tank that will be installed on all 403 existing platforms. The system includes a second-generation thermal sight, the Far Target Locate capability, and an eye-safe laser rangefinder. The second-generation thermal sight consists of upgrades to the M1A1's infrared optics, an infrared focal plane array, associated analog and digital electronics, display, and brackets and cables. The FTL consists of a North Finding Module (NFM), bracket, cables and inputs from the existing laser rangefinder, and a Precision Lightweight Global Positioning Receiver (PLGR). The FTL formulates a targeting solution using inputs from the laser rangefinder, the PLGR and the NFM. The eye-safe laser rangefinder will replace the current non-eye-safe rangefinder.
The FTL will initially be unique to the Marine Corps, providing tank crews with accurate target location out to 8,000m with less than 35m Circular Error Probable (CEP). Milestone C ultimately releases $121.5 million in procurement to begin full rate production, followed by install and Initial Operating Capability in FY '06. All 403 systems will be fielded and installed for Fully Operational Capability by end FY '09.
Abrams Integrated Management (AIM)
The Abrams Integrated Management (AIM) program is completely rebuilding every
M1A1 Abrams tank in U.S. Army Europe over a three year perios. The AIM program is a part of the Recapitalization Program that was established to extend the life of the Army's aging legacy
equipment. AIM will provide long-term sustainment of M1A1 Abrams tanks through fiscal year 2025. Higher-than- normal mileage for the tanks during operations in the Balkans and training in Germany
made the overhaul necessary.
The Military Traffic Management Command's (MTMC's) 838th Transportation Battalion at Rotterdam, The Netherlands, received the first tanks for shipment to the United States in September 2000. Up to 75 percent of the tanks were not operational. MTMC transported the tanks to Anniston Army Depot, Alabama, where they are be disassembled. The hull, turret, engine, and other parts are sent to the tank production plant in Lima, Ohio, to be reworked. MTMC returns the rebuilt tanks to Europe, where they will be swapped one-for-one with tanks that still need repair. The first shipment of rebuilt tanks arrive in Europe by fall 2001.
|Crew||4 (driver, commander, gunner, loader)|
|Length With Gun Forward||387in|
|Maximum Governed Speed||42mph|
|Cross Country Speed||30mph|
|Speed, 10% Slope||17mph|
|Speed, 60% slope||4.1mph|
|Acceleration||0mph to 20mph in 7.2 seconds|
|Range||265 miles cruising|
|Vertical Obstacle Crossing||42in|
|Main Armament||120mm smooth bore cannon, M256|
|Coaxial Weapon||7.62mm machine gun, M240|
|Loader's Weapon||7.62mm machine gun, M240, on skate mount|
|Commander's Weapon||0.5-calibre machine gun, M2, on powered rotary platform|
|NBC Protection||200 SCFM, clean cooled air|
|Propulsion||Gas turbine engine, 1,500hp|
|Transmission||Hydrokinetic transmission (4 forward gear, 2 reverse gears)|
|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||42 MPH||42 MPH|
|Armament:||105 MM||120 MM||120 MM|
Advanced Gunnery Training System (AGTS)
In August 1990, Iraq invaded Kuwait, and soon after, President George H. W. Bush committed U.S. troops to the theater, first to defend Saudi Arabia, and then to eject Iraqi troops from Kuwait.
Redeployment and Retraining
The 3rd Armored Division, then commanded by Major General Paul Funk, was one of four U.S. heavy divisions deployed with VII Corps. The division and its equipment were shifted from Germany to Saudi Arabia, with in some cases, Army National Guard and Army Reserve elements taking over some of their duties in Germany, while in others, caserns were left virtually empty. One must note that this massive redeployment was possible only due to the Western victory in the Cold War, in which the 3rd AD helped to play an integral part by guarding the Fulda Gap.
After redeployment, the "Third Herd" acclimated to the desert climate and its troops faced new challenges in mobility, tactics and maintenance in a sandy and hot climate. Various National Guard and Army Reserve units were then attached to the division for the duration of the conflict, swelling the division's size to over 20,000 troops - 25% larger than during its time in Germany.
The majority of the division's troops never received Desert Battle Dress Uniforms due to a shortage, and fought instead in lightweight summer "woodland pattern" uniforms, covered by tanker suits or the ever-present and much-despised chemical warfare protective MOPP suits.
Finally, after months of training the division moved to the Line of Departure, alongside the 1st Armored Division on its left flank and the 2nd Armored Cavalry Regiment on its right flank. While the Iraqi Army concentrated much of its defenses in and around Kuwait itself, the 3rd AD and VII Corps launched a massive armored attack into Iraq, just to the west of Kuwait, taking the Iraqis completely by surprise.
Scouts from 2nd Brigade crossed on the afternoon of the 23 February 1991 just after 1500 hours. Less than two hours later, they had penetrated several miles into Iraq and managed to capture over 200 prisoners. On 24 February, the official first day of action, the division as a whole swung into action as part of a coordinated attack by hundreds of thousands of allied troops.
During the first day of battle, the Third Herd pushed 18 miles into Iraq, taking over 200 prisoners. By dawn of the second day, an additional 50 prisoners had been taken, with scouts reporting enemy reinforcements moving to meet the division.
The Second Day
At 1115 hours of the second day, all elements of the division were finally across the Line of Departure. The day was marked by hard pushing to penetrate deep and fast, striking for an objective south of Basra. In the course of its drive, various elements of the division engaged the enemy, taking prisoners, skirmishing, sometimes bypassing enemy strongholds to gain ground, other time engaging in full scale battle.
By nightfall of the second day, 3AD had driven 53 miles into Iraq, with dozens of enemy vehicles destroyed, hundreds of POWs captured, and was on the verge of achieving its first objective - an accomplishment that war planners had not anticipated.
The Third Day
On the third day of combat, 26 February, the division closed in upon its objective and faced for the first time the Iraqi Republican Guard, a much stronger foe than the forces the division had first engaged, and less inclined to retreat or surrender. Opposing forces included the highly touted Republican Guard "Tawakalna" Division, the Iraqi 52nd Armored Division and elements of the 17th and the 10th Armored Divisions. The division engaged in full scale tank battles for the first time since World War II, and as one of the division's veterans states "There was more than enough action for everyone".
Action continued after nightfall, and by 1840 hours, the ground and air elements of the 3rd AD could report over 20 tanks, 14 APCs, several trucks and some artillery pieces destroyed. Unfortunately, that same evening, the 4-32nd Armored Battalion lost the division's first casualties in a Bradley Fighting Vehicle to 25mm cannon fire - with two soldiers killed and three wounded. During the night, both darkness and sandstorms hampered soldiers' visibility, but thermal sighting systems on board the M1A1 Abrams tanks and Bradleys allowed gunners to knock out Iraqi targets.
The Fourth & Fifth Days
By the fourth day, the division reached its objective, and pursued its now retreating enemy. The division turned east, into Kuwait, continuing to inflict heavy casualties and capture troops as it rolled forward, often hitting new units whose defensive berms and foxholes faced south from their northern flank, rendering their defenses ineffective. By nightfall, forces facing 3AD had been virtually eliminated, with their remnants in full retreat.
By the fifth day of combat, the division had achieved all objectives and continued to push east to block Iraqi retreat from Kuwait, conducting mopping up operations. One hundred hours after the ground campaign started, President Bush declared a ceasefire.
At the height of the battle, the 3rd Armored Division included 32 battalions and 20,533 troops. It was the largest coalition division in the Gulf War and the largest U.S. armored division in history. In its moving arsenal were 360 Abrams main battle tanks, 340 Bradley Fighting Vehicles, 128 self-propelled 155 mm howitzers, 42 Apache attack helicopters, 27 multiple-launch rocket systems, and more.
Superior training, initiative and equipment had enabled the soldiers of the "Third Herd" to spearhead their way through the Iraqi Army, including opponents with Soviet-provided training and equipment. In the 100-hour Gulf War, 3AD destroyed hundreds of Iraqi tanks and vehicles, and captured more than 2,400 Iraqi prisoners. Fifteen troops of the 3 AD were killed between December 1990 and late February 1991.
In 1991, Division Historian Dan Peterson, comparing the performance of the division in World War II and Desert Storm stated "History does always repeat itself. 3rd Armored Division was the Spearhead in both wars."
Following the war, 3rd Armored Division was one of the first units rotated to Caoha, Kuwait, providing protection to Kuwait as it rebuilt.
Operation Desert Storm 1991
The 120mm ammunition system equips the MlE1 (Abrams) tank with a 120mm main armament. It consists of a family of kinetic energy (KE) rounds and a family of high explosive anti-tank (HEAT) rounds. The KE rounds use a high length over diameter ratio subcaliber projectile with a depleted uranium (DU) fin-stabilized rod as the penetrator element. Traveling at supersonic speed, this penetrator concentrates an extremely high level of kinetic energy over a relatively small surface area of the target. The high specific energy on target enables the KE round to penetrate even the most resistive armor plates. The HEAT rounds, on the other hand, take a shaped charge warhead to targets. This shaped charge warhead, with its inherent blast and fragmentation capability, also provides additional weapon defeat capability
All 120mm rounds use a common combustible case which structurally combines the ammunition'scomponents prior to firing and is completely consumed during firing. The combustible case is the primary reason for the superior interior ballistics performance of the 120mm ammunition. This breakthrough in cannon ammunition technology allows both a greater chamber volume for the propellant and a higher working chamber pressure, thus giving the rounds greater muzzle velocities and higher ballistic efficiencies. The combustible case also minimizes round weight and, because the metal base is the only element ejected, the armount of spent cartridge case material and propellant gas within the tank is is greatly reduced.
While the combustible case is thoroughly consumed during firing, further assurance of a clean tube and chamber for each successive round is provided by a cannon bore evacuator. The evacuator functions as a large vacuum device, sweeping all portions of the barrel interior free of the most minute particles. All 120mm rounds have a propellant containment device that prevents propellant spillage if the combustible cartridge case is damaged.
The 120mm smooth bore cannon system was developed by West Germany for the Leopard II tank. The ammunition produced by both countries is interoperable and interchangeable between the Abrams and the Leopard, thus ensuring maximum commonality within the NATO community.