Vernier Pitch Control Switch
The function of the vernier pitch control
switch is to allow the operator to select the
control source, or combination of control sources,
to control propeller pitch. When the vernier
pitch control switch is in the OFF position, the
operator can control propeller pitch only by
moving the control levers. When the vernier
pitch control switch is ON, the operator can
control propeller pitch by using both the control
levers and the in-and-out movement of the yoke.
The operator uses the control levers to set the
midrange for the yoke propeller pitch control
range.
Propeller Pitch Selector Switch
The propeller pitch channel selector switch is
located on the C&C keyboard at the engineer
station. This switch, labeled PROP A/B, allows the
operator to choose between channels of the CSEP
in case of an emergency or system fault.
Figure 6-11.-Propeller pitch control levers.
Propeller Pitch Control System Indicators
The function of the propeller pitch indicators
Propeller Pitch Control Levers
is to inform the operator of existing conditions. The
operator uses this information to move the craft as
The function of the propeller pitch control
effectively and safely as possible. This subsystem
levers is to allow the operator to control the pitch
informs the operator of the following conditions:
of the propellers. By controlling the pitch of the
Propeller control failure
propellers, the operator can control the speed and
direction of the craft. Figure 6-11 shows a detailed
Port and starboard hydraulic reservoir low
view of the propeller pitch control levers. Each
Port and starboard hydraulic pressure low
control lever has a detent stop at zero degrees of
propeller pitch with adjustable mechanical stops at
Propeller pitch
both ends. The propellers are adjustable from +40
to -30.
These indicators are provided at both the operator
control station and the engineer control station.
Propeller Pitch Drive Assembly
You have just read about the steering control
The propeller pitch drive works to position the
system and the propeller pitch control system.
propeller to the position ordered by the operator.
Now, let's take a look at another system that works
When the operator moves the control levers, an
with these two systems to allow the operator to
electrical signal range is produced and sent to the
maneuver the craft.
CSEP where it is amplified. From the CSEP, the
amplified signal is sent to the propeller pitch drive
LIFT FAN CONTROL SYSTEM
mechanism. The propeller pitch drive mechanism
turns
the
propeller,
causing
a
feedback
The lift fan control system allows the engineer
potentiometer to send a signal to the CSEP. When
to control the airflow to the cushion of the craft.
the feedback signal equals the command signal,
An emergency dump switch is provided at the
the propeller is in the ordered position, The
operator control station to allow the operator to
propeller pitch drive mechanism can also be
stop the craft in an emergency by taking it off the
triggered by the vernier pitch control circuit we
air cushion.
will describe in the following paragraph.
