XM-1 and M1 Abrams: The Last Chrysler Tanks
Chrysler tank development and production goes back to World War II, but the modern M-1 “Abrams” tanks has a much more recent pedigree.
The M-1 tank had double the power, cross-country speed, and mobility of existing combat tanks, when launched; Chrysler also provided it with self-diagnostic telemetry and, later, on-board diagnostics.
M-1 tank development
In 1970, the Chrysler Defense Division joined the joint U.S./German development of the MBT-70 tank in 1970 to design a military battle tank, targeting the Soviets. The Department of Defense, however, had higher targets, and in 1973, both Chrysler and General Motors began building competing tanks to replace Chrysler’s M60 and the MBT-70 project. The tanks were given to the U.S. Army for trials in February 1976; in November, the Army’s selection committee chose Chrysler’s XM-1 prototype, possibly because of its powerful, flexible-fuel turbine engine, according to Major General Robert J. Sunell.
In 1978, Chrysler Corporation began producing the turbine-powered XM-1 tank — the “X” (for “experimental”) now dropped.
Amidst the loans guarantees of 1979, M1 Abrams tank production began at the Lima Army Modification Center in Lima, Ohio (now known as the Lima Army Tank Plant or the Joint Systems Manufacturing Center). The tank was named after the late General Creighton W. Abrams, commander of the 37th Armored Battalion and Army Chief of Staff.
The M1 tank was released through the Highland Park factory, the same complex that housed the turbine research group. The tank's electronic assemblies were produced through the Huntsville factory by Pentastar Electronics (PEI), the renamed Military/Public Electronics Systems division.
Chrysler’s Huntsville engineers, many veterans of the space program and the Moon rockets, created a testing system, the Direct Electrical System Test Set (DSESTS), for Chrysler cars and military vehicles; it is still used today (as of late 2012) for the Abrams and Bradley tanks as well as the Marines’ LAV. Later, PEI created a sidecar embedded diagnostic system which put full diagnostics into the tank itself. (In 1997, PEI was purchased by investors, ending up with Finmeccanica in 2003; but it still exists as a separate entity, now called DRS Technologies. Chrysler’s tank manufacturing was sold to General Dynamics in 1986.)
|Refueling Time||10 minutes|
|Refueling/Rearming Total Time||30 minutes|
|Fuel Mileage||0.6 mpg|
|Basic Idle||10 gallons|
|At a Tactical Ideal||About 30 gallons/hour|
Powered by a 1,500-horsepower gas turbine engine, the four-crew-member M1 tank has a power-to-weight ratio superior to competing tanks; the engine is also smaller, providing more available space. The power-to-weight ratio allows the tank to maneuver better and be faster than other tanks. It goes from 0 to 20 mph in 70 seconds – while getting less than 1 mpg; recent models of the M1 tank have a 490-gallon fuel tank, allowing it to travel about 265 miles as it uses gasoline, diesel, or jet fuels.
The tank has a six-speed hydrokinetic transmission, with four forward gears and two reverse gears. Because of its manueverability and quiet operation, the tank was nicknamed “Whispering Death.”
Major General Sunell said:
Early on, I wasn’t sure about the turbine engine because it was new. I wasn’t completely sure about how well it would do. As I look at it now, that engine has turned out to be excellent. It eats a lot of fuel, but it’s a very reliable engine, and it gives you the power you need, and it saves you space.
The turbines were originally produced by Lycoming (Stratford Army Engine Plant), then by Garrett (who worked with Chrysler on the cars), and was finally made by Honeywell as the AGT1500. The “recuperator” in the AGT1500 is a direct decendent of the twin “regenerators” used in the third generation Chrysler turbine engines, which also used Garrett power turbine wheels and compressors (according to Bob Sheaves).
The M1 benefits from special armor that was developed by the British Army’s research facility in Chobham, England. The variation of the “Chobham” armor, created by Chrysler’s own Pete Gruich, consists of a steel armor plate with layers of ceramic composites and steel on top; the layers have heat and shock-absorbing materials and can defeat high explosive anti-tank (HEAT) rounds. Updated M1s have layers of steel and depleted uranium to protect against tank rounds and most missiles, excluding Hellfire missiles. There is also an advanced air filter system to protect the crew from chemical and biological attacks.
|Length||384 inches (32 ft)||387 inches (32.25 ft)|
|Width||144 inches (12 feet)|
|Height||93 inches (7.79 ft)||96 inches (8 ft)|
|Weight||60 tons||67.6 tons||68.7 tons|
|Crew||4: commander, gunner, loader, driver|
|Turret Height||93.5 inches|
|Ground Clearance||19 inches|
|Vertical Trench||9 feet|
|Power:Weight Ratio||25 hp/ton||23.8 hp/ton||21.6 hp/ton|
|Max Speed (governed)||45 mph||42 mph|
|0 to 20 mph||7 seconds||7.2 seconds|
|Cruising Range||275 miles||265 miles|
On board, the M1 tank were armed with a M68A1 105-mm rifled gun, the same artillery used on the M60 MBT. Today, the tank also has three machine guns – a Browning .50-caliber M2 and two 7.62-mm M240s (one on the cupolas on the turret’s top and one next to the main gun).
Another special feature of the M1 battle tank is its advanced computer-controlled fire control system. Wind gusts, the turret's motion, and the tank's tilt are all monitored by various sensors. A computer adjusts the weapons in order to remain aimed at its target.
The M1 tank remained untested for more than ten years. In 1991, the U.S. took about 1,800 M1A1 tanks into Saudi Arabia for combat during Operation Desert Storm; it proved to be superior to the T-55, T-62, and T-72 tanks the Iraqis had gotten from the Soviet Union. Only 23 M1A1 tanks were destroyed, nine of them with repairable damage. The M1A1's shooting range was a huge advantage in combat; the tanks were capable of shooting targets up to 8,200 feet away – much better than the Soviet/Iraqi tanks' 6,600 feet.
In 2003, the M1 Abrams tanks entered Iraq again during Operation Iraqi Freedom, but about 80 tanks were destroyed by Iraqi attacks. Many of the tanks were crippled by the use of Soviet RPG-7 rocket-propelled grenade weapons, fired at the three most vulnerable points on the tanks: the tracks, rear, and turret top. This vulnerability was largely addressed with the TUSK, an urban survival kit, as well as new features such as the “Softkill” active protection system, which can divert many types of guided (by wire, radio, thermal, and infra-red) anti-tank missiles.
The tanks did survived multiple close-range hits from “Lion of Babylon” tanks and ATGMs; rounds from other Abrams tanks were unable to penetrate the front and side armor in friendly fire incidents.
M1A1 and M1A2
There are two other versions of the M1 – the M1A1 (1985-1993) and M1A2; both versions, plus the M1, are all still in service. The M1A1 had an upgraded suspension, new turret, biological/chemical/nuclear protection system, upgraded armor, and a 120-mm gun which replaced the M1’s 105-mm gun. The M1A2 includes a thermal viewer, independent weapon station, position navigation equipment, and a radio interface unit with a digital data bus. Some of the older M1 tanks have been upgraded to M1A2 specifications.
Post-Chrysler: the TUSK urban survival kit
The Tank Urban Survival Kit (TUSK) was created in the mid-2000s, long after Chrysler lost its military division; it was created because tanks have generally been at a disadvantage in urban surroundings, when attackers can get close to the vehicle, and hit it from any angle, including from above. The armor was upgraded, with slats on the rear (to counter rocket-propelled grenades), reactive armor on the sides, a thermal sighting system and transparent shield for the top machine gun, and a remote turret with a .50 caliber machine gun, so the commander did not have to be exposed. The tank also gained a phone on the outside, so soldiers outside the tank could communicate with its operators.
The TUSK was designed to be installed in the field. All items other than the reactive armor are expected to be retrofitted to the entire Abrams M1A1 and M1A2 tank fleet.