Figure 6-10.-Bow thruster turning vanes.
Now that you have read about the most important
BOW THRUSTER TURNING VANES. The
components of the steering control system, let's take a
purpose of the turning vanes is to direct airflow
look at an associated system that is supplied by the
toward and out of the bow thrusters. Figure 6-10
same hydraulic power sourcethe propeller pitch
shows the configuration of the bow thruster turning
control system.
vanes. Notice how the fixed vanes are attached into
the air duct of the lift fan module and into the bow
PROPELLER PITCH CONTROL SYSTEM
thruster volute. This design allows the airflow to
reach the bow thrusters with a minimum of
The purpose of the propeller pitch control system
turbulence inside the volute and air duct.
is to allow the operator to control the speed and
direction of the LCAC by changing propeller pitch.
BOW THRUSTER CHANNEL SELECTOR
The LCAC propeller assembly is capable of both
SWITCH. The bow thruster channel selector switch
forward and reverse pitch. The greater the angle of
is located on the C&C keyboard at the engineer
pitch, the faster the craft will move.
station. This switch, labeled BOW THRUSTER A/B,
allows the operator to choose between channels of the
The propeller pitch control system is composed of
CSEP in case of an emergency or system fault.
the yoke assembly, propeller pitch indicator, a control
unit, propeller pitch control levers, potentiometers,
BOW THRUSTER INDICATORS. The function
and amplifiers. The control station operator controls
of the bow thruster control system indicators is to
inform the operator of existing operating conditions
hand console and the in/out movement of the yoke.
and alarm conditions concerning the following areas:
Pushing the yoke in or pulling it out will send
electrical signals to the electrohydraulic servo valve
Bow thruster control failure
and actuator, allowing the operator to control the
pitch of the propellers. An indicator at the operator
Port and starboard hydraulic reservoir low
station provides an indication of propeller pitch.
Figure 6-5 shows the physical location of the
Port and starboard hydraulic pressure low
propeller pitch controls in the operator station. Let's
talk shout some of these controls and how they work.
