Cessna 172N - Page 123

CESSNA
MODEL 172N
SECTION
7
AIRPLANE
& SYSTEMS
DESCRIPTIONS
pressure gage,
oil
temperature
gage,
and a tachometer. A carburetor
air temperature
gage
is also
available.
The oil
pressure
gager
located on the
left side
of
the
instmment
panel,
is
operated
by oil
pressure. A
direct
pressure
oil
line
from
the
engine
delivers oil
at engine
operating
pressure
to
the
oil
pressure
gage.
Gage
markings indicate that minimum
idling
pressure
is
25
PSI
(red
line),
the
normal
operating range is 60 to 90 PSI
(green
arc), and murimum
pres-
sure
is
100
PSI
(red
line).
Oil
temperature is indicated by a
gage
adjacent to the oil
pressure
gage.
The
gage
is operated by an electrical-resistance
type
temperature
sensor which
receives
power
from the
airplane
electrical system.
Oil
temperature
limitations
are
the
normal operating range
(green
arc)
which
is
38'C
(100"F)
to 118"C
(245"
F),
and
the
mzu<imum
(red
line) which
is
118'C
(245"F).
The engine-driven mechanical tachometer is
located
near
the
lower
portion
of the
instrument
panel
to the left
of the
pilot's
control
wheel.
The
instrument is
calibrated in increments
of
100
RPM and indicates
both engine and
propeller
speed. An hour meter
below
the center
of the
tachometer
dial records elapsed engine time
in hours
and tenths.
In-
strument
markings include a
normal operating range
(green
arc)
of
2200
to 27OO RPM, and
a maximum
(red
line) of 2700 RPM.
A
carburetor
air
temperature
gage
may be installed
on the right
side
of
the
instnrment
panel
to help detect
carburetor icing
conditions. The
gage
is marked in 5o increments from
-30"C
to
+30oC,
and has a
yellow
arc
between
-15'C
and +5"C
which indicates the temperature
range
most
conducive to icing
in
the
carburetor.
A placard
on the lower half of
the
gage
face
reads KEEP NEEDLE
OUT
OF
YELLOW
ARC
DURING POS-
SIBLE CARBURETOR
ICING
COI{DITIONS.
NEW
ENGINE
BREAK-IN AND OPERATION
The engine
underwent a nrn-in at
the
factory
and is
ready
for the
full
range
of
use.
It is, however,
suggested
that
cmising
be
accomplished
at
65Voto75Vo
power
until a total
of
50
hours has accumulated or oil con-
sumption has stabilized.
This
will
ensure
proper
seating
of
the rings.
The
airplane
is delivered from
the
factory with corrosion
preventive
oil in the engine. If, during the
first
25 hours, oil must
be
added,
use
only aviation
grade
straight
mineral
oil cordorming to Specification No.
MIL-L-6082.
7
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