Dynamics delivered the first M1 Abrams battle tanks
to the U.S.
Army in 1980, but it wasn't until 1991's Operation Desert
Storm that the world fully appreciated the weapon's
capabilities. The U.S. Army and Marine
Corps deployed nearly 2,000 M1s to the Persian Gulf, and
all but 18 returned in working condition. The tanks sped over
the rough desert terrain, through heavy smoke from oil fires,
destroying almost all of the Iraqi's Soviet tank fleet. In the
entire operation, the United States didn't lose a single M1
The M1 is the world's preeminent tank because it combines
four crucial qualities:
edition of HowStuffWorks,
we'll examine these major components to find out how the M1
completes its mission.
- Superior mobility - to get to targets and escape attack
- Superior sensors and controls - to locate and hit
- Superior firepower - to destroy targets
- Superior armor - to withstand attack
Great Britain developed the
modern tank in the early 1900s as a response to the rise of
trench warfare. In the battles of World War I, opposing
forces dug parallel trench fortifications guarded by barbed
wire and machine gunners. This strategy made for high
casualties on both sides. To advance any ground, soldiers had
to storm the enemy's trench, sacrificing dozens of men for the
chance that a few might make it through the mud and hail of
The British and their allies needed an armored "land boat,"
a machine that could plow through mud, barbed wire and heavy
fire to clear a path for infantry troops. The final design had
- Caterpillar tracks
- Internal combustion engine
Caterpillar tracks work on the same principle as a
conveyer belt. The tank engine rotates one or more steel
sprockets, which move a track made up of hundreds
of metal links. The tank's wheels ride along the moving
track, just like the wheels in a car run along the road.
Earlier tracked vehicles weren't practical in battle because
engines were too cumbersome and unreliable. The internal
combustion engine made tracked military vehicles feasible.
Tracked vehicles can move easily over rough terrain because
the track makes contact with a wide area of the ground. A car
grips the ground with only the bottom portion of four tires, but a
tank grips it with dozens of feet of track. Additionally, the
track has heavy tread that digs into muddy surfaces, and it
never goes flat like a tire.
The hull is the bottom portion of the tank -- the
track system and an armored body containing the engine and
transmission. The hull's job is to transport the top portion
of the tank, the turret, from place to place. The
turret is an armored structure supporting one or more guns --
typically a heavy cannon and a couple of machine
The turret sits in a wide circle at the center of the hull.
In the conventional design, a spur gear in
the hull (called the traverse gear) engages an internal
gear lining the inside of the turret. Turning the traverse
gear rotates the turret on the hull, allowing the tank crew to
aim the main gun without turning the entire tank. The crew can
also pivot the main gun up and down.
Soon after the British deployed their new weapon, the
Germans developed tanks of their own. With tanks on both
sides, the weapon's role changed significantly. Instead of
taking out trenches, today's tanks mostly battle other tanks.
As we'll see in the next few sections, the M1 is specifically
designed for this sort of combat.
GameTanks got their name
from a diversionary tactic. The Allied forces built the
first tanks in absolute secrecy because they wanted to
catch the Germans off guard. In order to conceal their
plan, they told the workers building the weapons that
the machines would be used to transport water on the
battlefield. They shipped the machines in crates marked
"tank," and the name stuck.
The M1 Abrams is named after the late General
Creighton W. Abrams, who served as Army Chief of Staff
and commander of the 37th Armored Battalion. The M1 is
informally known as "The Beast," "Dracula" and
"Whispering Death," referring to its impressive
firepower and quiet operation.
The M1 uses a 1,500-horsepower gas turbine
engine to achieve high mobility. Gas turbine engines have
a much better power-to-weight ratio than reciprocating
engines. That is, they provide a lot more power without
adding a lot of weight. Turbine engines are also a lot smaller
than comparable reciprocating engines, so you can do more with
the available space on the tank.
The low-weight, high-power turbine engine lets the M1 move
faster and maneuver better than most comparable tanks.
According to General Dynamics Land Systems, the tank can
accelerate from 0 to 20 miles per hour in 7.2 seconds, and it
can safely travel 30 miles per hour cross-country. The high
speed and agility do come at a price, however: Even with an
advanced digital fuel control system, the tank gets
less than a mile per gallon!
Photo courtesy U.S. Department of
An M1A1 tank
speeds across the Kuwaiti desert during Desert Storm.
The M1's turbine engine gives the tank the power and
agility necessary to maneuver in hostile
To give the tank decent traveling range, General Dynamics
had to give it some mammoth fuel tanks. The most recent M1
model holds 490 gallons (1,850 L), allowing the tank to go
about 265 miles (426 km) without refueling. The turbine engine
works with a range of fuels, including ordinary gasoline,
fuel and jet fuel.
The engine provides power to a six-speed automatic
hydrokinetic transmission (that's four forward gears and
two reverse gears). The transmission turns sprockets on either
side of the tank. The sprockets pull the track along.
3.0The M1 has gone through
several configurations in its 20-year history. The
original M1, which became operational in 1983, had a
relatively small main gun and limited armor. The M1A1,
introduced in the late '80s, had a larger gun and
improved armor. Over the years, the Army upgraded most
of its original M1s to at least M1A1 levels. The newest
M1, the M1A2, is characterized by vastly improved
onboard electronics and additional armor. In this
article, we mainly focus on the M1A2
The M1's primary weapon is a
120-mm M256 smoothbore cannon made by the German
Landsysteme GmbH. The "120-mm" designates that the cannon
fires 120-mm-wide rounds. "Smoothbore" means the inside
of the barrel is smooth, rather than rifled like most
guns. Smoothbore guns don't stabilize rounds as well as
rifled guns, but they can fire rounds at higher velocities
without suffering heavy damage.
The M256 fires a variety of training rounds and combat
rounds. Its two main combat rounds, generally known as
sabot and HEAT rounds (for high-explosive
anti-tank), inflict damage in very different ways.
Sabot rounds work
like a basic arrow. They don't have any explosive
power; they penetrate armor with shear momentum. The
heart of the sabot round is the penetrator -- a narrow
metal rod (typically depleted
uranium) with a pointed nose on one end and stabilizing
fins on the other. Before the round is fired, the rear part of
the penetrator is attached to a propellant case, and the front
part is attached to the sabot structure. The sabot's
purpose is to keep the narrow penetrator centered in the wide
On firing, the propellant casing remains in the chamber,
and the expanding gas pushes the sabot and attached penetrator
down the barrel. The sabot is attached to the penetrator with
relatively flimsy plastic, so it falls away as soon as the
round leaves the cannon. The heavy penetrator flies through
the air at high speed toward its target tank. Because of its
narrow shape, the penetrator focuses its full force into a
very small area, plowing straight through heavy armor. As the
penetrator enters the tank, heated fragments of metal fly off
in all directions, hitting anybody and anything inside.
Photo courtesy U.S.
The sabot separates
from the penetrator as a sabot round flies through the
HEAT rounds use
explosive firepower, rather than momentum, to penetrate
armor. At its nose, the round has an extended impact
sensor. When the impact sensor collides with a target, it
ignites an explosive, which melts surrounding copper. A
shape charge liner concentrates the molten metal and
hot gases into a narrow blast that cuts through the armor.
The M1 also has three machine
guns. It has a Browning .50-caliber M2 and a 7.62-mm M240
mounted to cupolas on the top of the turret, and
another M240 mounted next to the main gun.
The coolest thing about the M1's weaponry is its advanced
fire control system. An array of sensors constantly
monitors the tank's tilt, the turret's motion and any gusts of
wind, and a computer adjusts the gun accordingly to keep it
aimed at its target. With this system, the M1 can take out
other tanks while it's on the move. Less sophisticated tanks
have to come to a full stop to hit targets reliably.
The M1 is mainly composed of sturdy
rolled homogeneous armor (RHA) steel plates, sandwiched
around thicker protective material.
The core armor is a variation on the British Chobham
armor -- an arrangement of metal plates, ceramic blocks
and open space. HEAT and Sabot rounds may make it through the
outer layer of the armor, but they won't make it all the way
into the crew compartment. The ceramic material can absorb a
lot of heat, as well as heavy physical blows. The rest of the
hot gases or metal pieces spread out in the empty air pockets.
Updated M1 tanks have extra layers of steel and depleted
uranium that supplement the Chobham-style armor. This
combination will hold up to any tank round and most missiles
(the powerful Hellfire
missile is a notable exception).
crew keeps the M1's rounds in heavily armored storage
compartments. If something sets the ammunition off, the
armored structure keeps the explosion from blasting the crew
or completely destroying the tank. An onboard fire suppression
system will quickly extinguish any fires that occur inside the
Photo courtesy U.S. DOD
An M1A1 lays a smoke
The M1 is also equipped to handle chemical
or biological attack. An advanced air filter system
purifies all air coming into the tank so the crew isn't at
The tank can avoid attack entirely by hiding from
the enemy. The tank has two turret-mounted grenade
dischargers designed to launch smoke grenades in all
directions. The crew can also inject a little diesel fuel into
the exhaust to generate a cloud of heavy smoke.
Crew and Computers
The M1 is designed for a
four-person crew. The driver sits in the front section of the
hull, directly under the main gun. In order to fit in the
confined space, he has to lean way back in a reclining,
form-fitting bucket seat, sort of like a dentist chair. M1
crew members say that this is far and away the most
comfortable position in the tank.
The driver steers the tank using a motorcycle-style
handlebar, and accelerates by twisting a handle grip throttle.
The tank has a brake pedal on the floor, just like a car.
The driver navigates using three periscopes (also called
vision blocks). For night operations, he can substitute
vision sensor for one of the ordinary periscopes. The
driver also has a digital instrument panel, called the
driver's integrated display (DID), which provides
navigational data, as well as information about things like
speed, fluid level and engine performance.
The rest of the crew works in the turret basket (the
turret's interior compartment). The loader rides on the left
side of the turret, toward the back; the gunner rides on the
right side, towards the front; and the commander rides on the
right side, towards the back.
commander oversees the tank's operation, communicates
with other tank commanders and directs the rest of the crew.
He has several periscopes and a joystick-controlled
independent thermal night vision viewer to survey the
battlefield. He can monitor the tank's various systems and its
position on his integrated display.
Photo courtesy U.S.
A tank gunner
examines the commander's display unit on the
The gunner targets enemy vehicles and bunkers and
fires the main gun. He pinpoints targets using a stabilized
sight, with day vision and thermal night vision capabilities,
and a laser
range-finder that precisely measures the distance to the
target. He also controls the front machine gun and monitors
the main gun's general condition.
The loader pulls rounds from the ammunition
compartment and load them into the main gun. Generally, the
gunner tells the loader which sort of round to load.
The loader and commander may also operate the two machine
guns mounted on top of the turret. On the M1A2, they have to
open the tank's two hatches and fire the guns manually, so
it's not a viable option in a tank battle. The machine guns
are mainly for attacking infantry soldiers.
All of the M1s on the battlefield are linked together
by the inter-vehicle information system (IVIS). Using
IVIS, commanders keep track of the other tanks' positions,
transmit maps and share information about the enemy. In order
to hide communications from the enemy, the system uses
The combination of these advanced electronics, incredibly
strong armor and massive firepower make the M1 an almost
unbeatable opponent in tank warfare. But evolving technology
will eventually surpass the M1, and the weapon will take its
place alongside the dozens of other tanks that have come and
gone over the years. In the world of military science,
technological superiority has a short life span.
For more information about the M1 and other weaponry, check
out the links on the next page.
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