Washington Post
Wednesday, February 27, 1991

By Charles R. Babcock

Allied forces so far appear to have won handily their engagements with Iraqi armor, underscoring the decided advantage of the 1,800 U.S. Abrams M-1A1 tanks on the desert battlefield over Iraq's best counterpart, the Soviet-built T-72.

Such experts on Soviet weaponry as David Isby say the M-1A1's better targeting optics and advanced computer give it greater accuracy at longer range over the Soviet-built main battle tank. The Abrams has the additional advantage of being able to fire accurately at night and on the move.

Modern tanks fight, in effect, by shooting arrows at each other. The arrows are dense metal rods that are so heavy and travel so fast -- up to a mile per second -- that they pierce armor with brute force, scattering hot metal inside the tank where it can hit crewmen, ammunition and fuel. The round features a "sabot" -- for the aluminum "shoe" that surrounds the dense depleted uranium core to make it fit in the cannon barrel -- and is discarded in flight.

Tanks also carry high-explosive anti-tank (HEAT) rounds that can be fired at bunkers, other armored vehicles and troop concentrations. The same kind of shaped-charge explosive is used in most anti-tank weapons fired by jets, helicopters and ground troops because it does not require the velocity of the sabot round.

U.S. Marines advancing up the coast into Kuwait have been using older M-60 tanks, with added "reactive," or explosive, armor to ward off hand-held anti-tank warheads. The Marine tanks have been doing well against Iraqi armor too, according to U.S. briefers in Saudi Arabia.

Iraqi tanks must cope as well with A-10 jets and AH-64A Apache helicopters that can fire tank-killing missiles at even longer ranges.

The Soviet-made T-72 weighs 20 tons less than the Abrams and has a slightly larger but less accurate 125mm gun. "They're really two different generation tanks," said Orr Kelly, author of "King of the Killing Zone," a 1989 book about the Abrams.

Still, the T-72 can be a formidable opponent at close range, according to retired Army Maj. Gen. Donn Starry, one of the Abrams's developers. "I wouldn't sell it short," he said. Inside a mile, the Iraqi tank can be a "devastating piece of equipment," Starry added.

Before the allied air war against Iraq started Jan. 17, it was estimated that Iraq had more than 4,000 tanks in or near Kuwait, including about 500 T-72s assigned to elite Republican Guard armored units. The bulk of the Iraqi tank corps was made up of 3,500 older Soviet T-62, T-55 and T-54 models, some of which have been upgraded with heavier guns and armor.

Allied units have knocked out more than 400 Iraqi tanks in the ground war, briefers said yesterday, which, added to the estimated 1,700 tanks destroyed in the air war, means at least half the Iraqi tank force has been eliminated.

When the first two U.S. divisions were rushed to Saudi Arabia last August from Georgia and Texas, they were equipped with about 650 original model M-1 tanks, which were lighter and carried a smaller 105mm main gun. In October, the Army announced it was replacing those tanks with newer M-1A1s. "We wanted to give our men the best," explained Maj. Pete Keating, an Army spokesman. "We wanted an overmatch."

During the buildup before the ground offensive, such Army tank experts as Maj. Gen. Peter M. McVey of the Tank and Automotive Command in Warren, Mich., concentrated on ensuring that the Abrams's crews and commanders kept their tanks' gas turbine engines protected from sand or dust.

Extra air filters, seals and engines have been procured during the buildup, McVey said in an interview. As a result, he said, M-1A1 readiness rates in the Persian Gulf region consistently have been higher than 90 percent since mid-September.

The 1,500-horsepower engine on the M-1 has been controversial from the beginning of the $20 billion tank program. When the first prototypes were tested in 1977, the turbines had "severe problems" with dust ingestion, McVey said. "It had a poorly designed air compartment. We ate up a lot of engines." But the Army fixed the problem long ago, he said.

Starry said he was one of those initially opposed to switching from a diesel to a turbine engine. He thought it was "too risky" to stake the tank's future on a jet engine that might be incapacitated in dusty climates. "It's turned out to be a real winner," Starry said.

Another criticism of the Abrams is its fuel consumption. It gets about half-a-mile per gallon of fuel when on the move. "There are two things a tank commander always worries about," Starry said. "He's always looking over his shoulder for ammunition and fuel."

Army leaders say they consciously made the tradeoff to get speed and agility. To compensate, each tank carries 500 gallons of fuel, for a range of more than 200 miles. Armored units have extra fuel trucks to supply the Abrams, and Army officials said resupply by the unarmored tanker trucks should not be a problem in the Persian Gulf War because there is no Iraqi air force to threaten them.

McVey said the M-1A1 burns more fuel than the earlier M-60. "But what we get with the Abrams is the mobility, which is part of survivability, because if you're moving fast and changing direction, you're very hard to hit."

Last summer, a military reform group called the Project of Government Procurement cited 1988 Army reports to show the Abrams was failing several reliability requirements. Army spokesman Keating said test results show the tank now surpasses its requirements in two key areas.

When the M-1 program began in the early 1970s, the tank carried the 105mm gun, weighed less than 60 tons and cost no more than $500,000. Chrysler Corp., which delivered the first production models in 1980, sold its tank division to General Dynamics Corp. in 1982.

The A1 models produced after 1985 upgraded the gun to 120mm, weighed 63 tons and had an air pressure system to protect the four-man crew from nuclear, biological and chemical warfare. The switch to a bigger gun meant each tank could carry only 40 rounds of main-gun ammunition, down from 55 rounds for the 105mm gun.

Inflation and improvements have pushed the price of the latest models to about $3.5 million each, according to Keating. Since late 1988, depleted uranium has been added to existing layers of steel and ceramics to increase the armor protection and the weight to 67 tons for tanks coming off assembly lines in Warren, Mich., and Lima, Ohio. The uranium acts to disrupt the power of incoming HEAT shells.

Staff researcher Lucy Shackelford contributed to this report.

The M1 is the principal Main Battle Tank of the U.S. Army. Designed during the 1970s, it combines new armor, a high powered engine and a computerized firing system that allows it to hit stationary and moving targets while driving at top speed. Experts say the tank is possibly the best combination of firepower, mobility and protection in the western tank arsenal.

Weight: More than 60 tons
Length (with gun): 32 ft.
Height: 9 ft. 6 in.
Crew: 4

Main Armament: 120mm smoothbore cannon can fire at targets up to six miles away.

The tank's low silhouette and armored panels offer increased protection. Recent versions have high-tech steel and depleted uranium armor.

Driver sits at front of tank and drives from semi-reclining position. He is equipped with three periscopes, one of which can be replaced by a special scope for night driving.

Sophisticated electronics help pinpoint the enemy. Gunner designates a target, uses a laser and computer to determine range and trajectory, then opens fire.

Armored doors and bulkheads protect crew from ammunition or fuel explosions. Tank is also equipped with automatic fire-extinguishing system.

Engine. Though a powerful, 1,500-horsepower turbine engine makes the M-1 extremely mobile, the tank has very low fuel mileage. Top speed is just over 40 mph.

THE M-1's TANK-KILLING AMMUNITION

Sabot: Armor piercing weapon is fired from M-1's main cannon. As shell flies toward target, steel casing falls away. A dense metal dart at the Sabot's core continues flying toward the target at speeds of about one mile per second, penetrating enemy armor with brute force.

HEAT: High-explosive anti-tank round explodes just before hitting enemy armor. The force of the explosion is concentrated at the tip of the round, creating a jet of molten metal that can burn through enemy targets. Weapons of this type that concentrate explosive force at one point are called "shaped charges."

T-72 TANK

The T-72 is a Soviet main battle tank used by Iraq and several other countries. It was designed in the late 1960s and rushed into service to replace an earlier, unreliable weapon. The T-72 has added armor and can use an autoloading gun, but Pentagon officials say the armor is vulnerable to U.S. anti-tank weapons and the autoloader often misfunctions and injures crewmen.

Main armor: 125-mm smoothbore gun fires three main types of ammunition with a maximum range of over five miles.

The tank's low silhouette offers increased protection.

Some models are fitted with "reactive armor" that explodes on impact and dissipates the energy of anti-tank shells.

Weight: More than 45 tons
Length (with gun): 30 ft., 4 in.
Height: 9 ft, 3 in.
Crew: 3

Compiled by James Schwartz -- The Washington Post