Military Review English Edition November-December 2014 | Page 19

M1 ABRAMS

while stationary. In 2007, the Army did begin the Total
Integrated Engine Revitalization (TIGER) program
for the AGT1500, but with the objective of improving
reliability and durability, not fuel economy.20
Engine technology has come far since the Abrams
was introduced. The M1 turbine’s 1,500 horsepower
originally stood out from other tank engines for its
power, but now many other main battle tanks match
that output with more efficient diesel engines. For example, the Leopard II carries 37 percent less fuel and
yet has a range five percent greater than the M1.21
Of course, a decision to replace the M1’s engine
would involve a diverse set of factors not explored here
in detail. However, the tactical limitations that arise
from the M1’s current range, combined with the maturity of diesel engine technology and the age of the current M1 engine, make the conversion to a new engine
(diesel or otherwise) worth serious consideration.22
Industry successfully conducted trials with a diesel
engine in the M1 in 1997 in case any export customer
wished to pair a diesel engine with the M1, which suggests the compatibility issues are manageable.23 A key
engineering question would be the volume differences
between a diesel and the current turbine engine. If the
diesel is larger, it might force a reduction in internal
fuel capacity, at least partially cancelling out any range
increase.
Also, any fuel consumption reductions for the
Abrams need to be put in the proper organizational context. Tanks rarely operate alone, but rather as
part of combined arms battalions within an armored
brigade combat team. Each combined arms battalion
contains 58 Abrams and more than twice as many
other vehicles, thus diluting the overall fuel savings if
only the Abrams becomes more efficient.24
Nevertheless, reducing the fuel needs of the M1
could have ripple effects through logistics units. Less
survivable logistics units may reduce their need to traverse unsecured territory and thus reduce the associated risks.25 A reduced fuel demand for the Abrams also
could allow a reorganization of logistics units, freeing
up manpower for other units. Finally, less fuel demand
could mean that fewer logistics personnel are needed
in the critical early phases of a deployment (known as
a better tooth-to-tail ratio).
Other questions of concern include tactical issues
related to changes involving increased noise or smoke
MILITARY REVIEW  November-December 2014

output and loss of acceleration with the use of the diesel engine versus the turbine. The turbine provides excellent acceleration, and any reduction in that should
be explored for its tactical implications.

Non-Line-of-Sight Engagement
Capability
The Abrams is unique in presenting both chemical
energy (high-explosive antitank rounds) and kinetic
energy (sabot rounds) threats to enemy tanks, complicating the enemy’s defensive efforts.26 However,
though the 120 mm gun on the M1 is highly accurate
and lethal, it is limited to engaging line-of-sight targets out to a range of approximately 5 km.
Introduction of a new medium-range, nonline-of-sight (NLOS) munition for that gun would
greatly expand the engagement area, allowing more
dispersed Abrams units to exert influence over more
terrain. Such rounds would undoubtedly cost more
than those now fired from the M1, but their costs
may compare favorably with the cost of employing
a precision munition from an aircraft when launch
platform operating costs are included. Moreover, a
medium-range engagement capability would yield
survivability benefits by allowing the Abrams to
engage from beyond the range of most ground-based
anti-armor threats. Over the last decade, the development of a number of smaller and less expensive
precision munitions, many for use on d &