LCAC AND PHM PROPULSION SYSTEMS
The GSMs assigned to landing craft, air cushion
63 inches in diameter, providing the desired amount of
(LCAC) vessels and patrol combatant missile
airflow. The steering system consists of two rotatable
bow thrusters and two aerodynamic rudders. Figure 6-1
(hydrofoil) (PHM) class ships are responsible for the
is an illustration of an LCAC craft.
upkeep and maintenance of the propulsion and electric
plant control systems. If you are assigned to an LCAC
T h e LCAC engineering plant consists of
or a PHM, the watches you will stand will be different
propulsion, lift, and control systems. The plant is
from those on the DD-963, DDG-993, DDG-51, CG-47,
operated by the craft engineer/assistant operator while
and FPG-7 class ships. In this chapter you will read
the craft is underway. There are no traditional watches
about some of these differences and the associated
as these limited endurance craft carry only enough
responsibilities you may be expected to assume.
personnel to man the operating stations. The crew
After reading this chapter, you should be familiar
consists of an operator, craft engineer/assistant
with the operation of the engineering plant equipment
operator, navigator, load master, and deck hand/
on the LCAC and PHM class ships. The information
engineer. This small crew is completely responsible for
presented in this TRAMAN is designed only to
underway operations, and embarkation and dis-
familiarize you with the equipment on these ships. (In
embarkation of troops and supplies. The only GS is the
chapter 7, we will discuss the electric plants for these
craft engineer/assistant operator.
ships.) Remember, you should always use the
appropriate EOSS and PQS to qualify for a particular
AVCO LYCOMING TF40B GAS
watch station.
TURBINE ENGINE
After reading this chapter and completing the
The AVCO Lycoming TF40B gas turbine engine is
associated self-study questions in the NRTV, you should
the major propulsion plant for the LCAC. As a GSM,
have acquired enough knowledge to begin qualifying at
you will come into contact with the TF40B if you are
the individual watch stations on board these ships. Even
assigned to an LCAC or to one of its maintenance
though you may never be assigned to an LCAC or PHM,
depots.
the information in this chapter should familiarize you
enough with the equipment to help you advance in the
There are four TF40B engines on the LCAC, two
GS rating. As you become more senior in the GS rating,
on the port side and two on the starboard side. These
you may find yourself assigned to an LCAC or PHM
engines are the power sources that drive the lift fans,
class ship, or to one of their maintenance depots. In
propellers, and forward and aft gearboxes. In the
either case, this indoctrination could help you begin your
following paragraphs, we will take a look at the TF40B
qualifications.
in terms of its design and normal operating
characteristics. Later in this chapter, we will take a look
at the control and other systems for its functions.
LANDING CRAFT, AIR CUSHION
The LCAC is a high-speed, ship-to-shore,
DESIGN AND OPERATION
over-the-beach vehicle that will deliver a 60-ton payload
to the ground elements of a Marine amphibious force. It
The TF40B is a direct-drive, high-speed turbine
provides the Navy and Marine Corps with high-speed
consisting of a 2-stage, free-power turbine and a
delivery capabilities to support amphibious operations.
combination 7-stage, axial-centrifugal compressor
The LCAC is an air cushion vehicle that is powered
driven by a 2-stage, axial-flow turbine. It also
by four AVCO Lycoming TF40B marine gas turbines
incorporates a reverse-flow, annular-type atomizing
that provide a total of 15,820 horsepower (hp). Two
combustor chamber assembly, oil cooler assembly,
shrouded reversible pitch propellers provide forward
topmounted accessory gearbox module, and an integral
and reverse motion. The air cushion on which the craft
lubrication system. The major sections of the TF40B are
rides is created by four double-entry fans. These fans are
shown in figure 6-2.
