Function: Main battle tank (MBT).









Description: 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 hatched, 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.







History: Fielded in February 1980, the M1 General Abrams main battle tank revolutionized armored warfare. Incorporating an advanced shoot-on-the-move fire control system, a thermal imaging sight, a 1500 horsepower gas turbine engine and an advanced armor design similar to the Chobham armor developed in England, the M1 was the most lethal armored vehicle in the world. Conceived in 1971 as a replacement for the aging M60 tank, which was itself an extension of the 1050s era M 47/48 program, the M1 was going to be of a completely new design, establishing a new family of American main battle tanks. Providing the Abrams with a true shoot on the move capability, the fire control system automatically corrects for range, turret slew (motion) rate, crosswind, and tank axial tilt (cant). In addition, the gunner manually enters ammunition or weapon type, air and ammunition temperatures, barometric pressure, and gun tube wear, while range is instantly calculated by a Nd:YAG (Neodymium doped Yttrium Aluminum Garnet) near infrared laser rangefinder. Lastly, the gunner can compensate for gun tube deformation (caused either by heat generated from firing the cannon or atmospheric changes) through the use of a muzzle reference system, which allows for a rapid realignment of the cannon and the gunner's primary sight.



The Chobham armor built into the M1 represents a veritable leap in armor technology. Composed of layers of metal, ceramics, and spaces, this new armor is far superior to RHA (Rolled Homogeneous Armor) in defeating kinetic and chemical energy weapons. To increase crew safety and survivability, all of the M1's ammunition is stored in armored compartments which are designed vent dangerous gasses and fragments away from the crew in the event of an ammunition explosion. The crew and engine compartments are equipped with an automatic fire suppression system, utilizing numerous fire detection sensors and pressurized Halon gas, which can react to and suppress a compartment fire in less than 250 ms.



To survive on the NBC (Nuclear, Biological, Chemical) battlefield the M1 is also equipped with both an over pressurization and air sterilization system which will protect the crew from these hazards and allow them to continue combat operations without having to wear protective overgarments and masks while buttoned up inside the vehicle.



Lastly, the M1 was the first land combat vehicle to utilize a gas turbine multi fuel engine, which offers a higher power to weight ratio than any other contemporary tank power plant and gives the Abrams unparalleled tactical mobility and cross country speed. The M1 retains the M68 105mm rifled cannon used on the M60 series tanks, which was originally based on the British M7 105mm cannon design, and is capable of firing both rifled and fin stabilized ammunition. In addition, the M1 is equipped with two M240 7.62mm machine guns; one mounted coaxially with the main gun and fired by gunner, and the other mounted at the loader's station. The Commanders Weapon Station (CWS) is equipped with an M2 heavy barrel Caliber .50 machine gun. The CWS can be reconfigured to fire the M240 machine gun as a substitute.) The M1 is equipped with a pair of M250 red phosphorus smoke grenade launchers and is capable of generating smoke by injecting diesel fuel into the engine exhaust.



Originally designated the XM1, the first production model was designated the M1, of which 2,374 were built between 1982 and 1985. In 1984 the M1IP (Improved Product) was introduced, which was outwardly identical to the M1, but which incorporated a number of internal automotive, electronic and armor improvements. Production of the M1IP was halted at 84 tanks in 1986, when the Lima and Detroit tank plants were reconfigured to produce the up-gunned 120mm M1A1. In 1992 a study was conducted evaluating the feasibility of upgrading the Army's fleet of M1s to M1A2 SEP (Standard Equipment Package) standard and low rate production was approved in 1994. Since then the Army had agreed to convert 547 M1s to the M1A2 SEP standard.