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 are much more recent. When launched, the M-1 had double the power, cross-country speed, and mobility of existing combat tanks — along with Chrysler self-diagnostic telemetry adapted from Apollo space (later, they moved to on-board diagnostics).
M-1 tank development
In 1970, the Chrysler Defense Division joined a U.S./German effort to design a new military battle tank. The Department of Defense had greater needs, though, and in 1973, both Chrysler and General Motors began developing competing tanks to replace Chrysler’s M60 as well. The competing prototypes were given to the U.S. Army for trials in February 1976, and in November, the Army’s selection committee chose Chrysler’s XM-1 prototype, partly because of its turbine engine, according to Major General Robert J. Sunell.
Just two years later (in 1978), Chrysler Corporation began producing the turbine-powered M-1 tank at the Army Modification Center in Lima, Ohio (now known as the Lima Army Tank Plant or the Joint Systems Manufacturing Center) and the Highland Park complex, which also housed the turbine research group. It was named after the late General Creighton W. Abrams, commander of the 37th Armored Battalion and Army Chief of Staff. The tank’s electronic assemblies were produced through the Huntsville factory (later to become Pentastar Electronics, or PEI).
With decades of support for the Moon rockets behind them, Chrysler engineers created a testing system, the Direct Electrical System Test Set (DSESTS), for cars and military vehicles; it is still used (as of 2012) for the Abrams and Bradley tanks and the Marines’ LAV. Later, PEI 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 Time||30 minutes|
|Fuel Mileage||0.6 mpg|
|Fuel Use at Idle||10 gallons/hour|
|Fuel Use, Cross-Country||60 gallons/hour|
|At a “Tactical Ideal”||About 30 gallons/hour|
Powered by a 1,500-horsepower gas turbine engine, the four-person M1 tank has a power-to-weight ratio superior to competing tanks; the engine is smaller as well. It goes from 0 to 20 mph in 7 seconds – albeit 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 fuel.
Major General Robert 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 tank has a six-speed transmission, with four forward gears and two reverse gears. Because of its quiet operation, the tank was nicknamed “Whispering Death.”
The turbines were originally produced by Lycoming at the Stratford Army Engine Plant, then by Garrett, and finally by Honeywell; the current version is called 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 uses a variation of armor developed by the British Army in Chobham, England. The altered version, created by Chrysler’s Pete Gruich, uses steel armor plate covered with layers of ceramic composites and steel; the composites’ heat and shock-absorbing properties can defeat high explosive anti-tank (HEAT) rounds. Updated M1s have layers of steel and depleted uranium to protect against tank rounds and many missiles, and an air filter system to protect the crew from chemical and biological attacks.
|Length||384” (32 ft)||387” (32.25 ft)|
|Width||144 inches (12 feet)|
|Height||93” (7.8 ft)||96” (8 ft)|
|Weight||60 tons||67.6 tons||68.7 tons|
|Crew||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||7.0 seconds||7.2 seconds|
|Cruising Range||275 miles||265 miles|
The M1 tank was always 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). An advanced fire control system monitors wind, the turret's motion, and the tank’s tilt, adjusting weapons as needed.
It took over ten years for the M1 to see action; in 1991, the U.S. took about 1,800 M1-A1 tanks into Saudi Arabia for Operation Desert Storm, where it was superior to the Soviet T-55, T-62, and T-72 tanks used by the Iraqis. 23 M1A1 tanks were destroyed (nine of them were repairable). The M1A1’s shooting range was an advantage in combat; the tanks were capable of shooting targets up to 8,200 feet away – much better than the Soviet tanks’ 6,600 feet.
In 2003, the M1 Abrams tanks entered Iraq again during Operation Iraqi Freedom, but about 80 were destroyed, many by Soviet RPG-7 rocket-propelled grenade weapons, fired at the most vulnerable points. This 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 survived multiple close-range hits from “Lion of Babylon” tanks and ATGMs; rounds from other Abrams tanks did not penetrate the front or side armor in friendly fire accidents.
M1A1 and M1A2
The M1A1 was produced from 1985 to 1993; the M1A2 was built later. Both versions, as well as the original M1, are 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 M1 tanks have been upgraded to M1A2s.
The Tank Urban Survival Kit (TUSK) was created in the mid-2000s, to address the problem of attackers being able to get close to the vehicle and hit it from any angle. Slats were put onto the rear to counter rocket-propelled grenades; reactive armor was used on the sides; thermal sighting and a transparent shield were added to the top machine gun; and a remote turret was used with the .50 caliber machine gun, to avoid exposing the commander. A phone was placed on the outside for easier contact with ground soliders. All TUSK items other than the reactive armor are expected to be retrofitted to the M1A1 and M1A2 fleet.