G~'402C
MODEL
SECTION
7
AIRPLANE
&
SYSTEMS
DESCRIPTIONS
-
-
Alternate
Air
Control
An
alternate
air
control
is
provided
for
each engine, see Figure 7-1.
These mechanically
actuated,
two-position controls are located
on
the
instrument panel
below
the
pilot's
control wheel.
Normally
the controls
are pushed
in.
providing cold
filtered
ram
air
to
the engines.
When
the
controls
are pulled
fully
out,
warm
unfiltered
air
from
inside
the cowling
is
provided to the engines. A locking
feature
is
provided
for
each control
to prevent inadvertent
alternate
air
control
position
change. Rotating the
control clockwise engages the locking
mechanism.
ENGINE
Oil
SYSTEM
The
engines
installed
in
the
airplane
have
a wet
sump
type, pressure
lubricating
system. Oil temperature
is
controlled
by
a thermally operated
valve
which
either
routes
oil
through the
externally
mounted
cooler
or
bypasses the
oil
around the cooler. Oil
is
routed through
internal
pas-
sages to
all
moving
parts
of the engine
which
require
lubrication.
In
addition
to providing lUbrication
and
cooling
for
the engine, the
oil
is
used
for
control
of
the
propeller,
actuating the turbocharger waste gate
and
for
lUbricating the turbocharger.
Oil pressures
from
both engines are routed
into
the fuselage. to the
left
and
right
engine gages, see Figure 7-1.
where
direct
oil
pressure
readings are mechanically displayed.
The
oil
temperatures of both engines
are measured
on
the output
side
of the
oil
coolers.
The
measurements are
electrically
transmitted to the
left
and
right
engine
gages
where
the
oil
temperatures are displayed.
IGNITION SYSTEM
Each
engine
is
equipped with a dual
ignition
system.
The
ignition
systems
are
entirely
independent
from
each
other
such
that
a
failure
of
any
part
of
One
system
will
have
no
effect
on
the other system.
Each
system
consists
of
a
magneto
located
on
the
rear
engine accessory case.
ignition
harness to
distribute
the
electrical
energy
and
a spark plug
in
each engine
cylinder.
The
left
magneto
fires
the
lower
right
and
upper
left
spark
plugs while the
right
magneto
fires
the upper
right
and
lower
left
spark
plugs.
When
the primary
circuit
of each
magneto
is
electrically
grounded
by
placing the
magneto
switch
in
the
OFF
position,
the
magneto
will not
produce a spark.
With
the
magneto
switch positioned to
ON,
the primary
magneto
circuit
is
ungrounded. allowing a high voltage spark to
be
produced
to
fire
the spark plugs. During engine
starting,
a high voltage
vibrator
supplements the
magneto
spark to assure a
fast
start.
FUEL
INJECTION SYSTEM
Fuel
is
supplied to the engine using a low-pressure
injection
system.
The
fuel
is
injected
into
the
cylinder
head
adjacent to the intake valve
on
all
cylinders.
This continuous flow type
injection
system controls fuel
flow to
match
engine airflow. A
manual
mixture control
and
a flow gage,
see Figure 7-1.
indicating
fuel flow are provided
for
precise leaning
at
any
combination of
altitude
and
power
setting.
There are
no
moving
parts
in
this
system except
for
the engine-driven fuel
injection
pump.
1
November
1979
7-37
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