Cessna 172N - Page 56

SECTION 4
NORMAL
PROCEDURES
CESSNA
MODEL
172N
mined
by using
your
Cessna
Power
Computer
or
the data in Section
5.
NOTE
Cmising
should be
done at
65Vo
to
75Vo
power
until a totat
of
50 hours
has
accumulated or oil consumption
has
sta-
bilized.
This
is to ensure
proper
seating
of the rings
and
is
applicable
to
new engines, and engines
in
service
fol-
lowing cylinder
replacement
or
top overhaul
of one
or
more cylinders.
The
Cruise
Performance
Table, Figure 4-3,
illustrates
the true
air-
speed
and nautical miles
per gallon
during
cruise for various
altitudes
and
percent
po\ryer.
This
table
should be used as a
guide,
along with
the avail-
able
winds aloft information,
to
determine
the
most
favorable
altifude
and
power
setting
for a
given
trip.
The
selection
of
cruise
altitude
on
the
basis
of
the most
favorable
wind conditions
and the
use of
low
power
set-
tings
are significant
factors
that
should
be considered
on
every trip to
reduce
fuel consumption.
To achieve the
recommended lean mixture
fuel consumption
figures
shown
in
Section
5,
the
mixture
should
be
leaned
until
engine
RPM
peaks
and drops
25-50
RPM. At
lower
powers it
may be necessary
to
enrichen
the mixture slightly to obtain
smooth
operation.
Should
it
be
necessary
to cruise
at higher
than
75Vo
power,
the
mixture
should not
be
leaned
more
than is
required
to
provide peak
RPM.
Carbr.rretor ice, as evidenced by an unexplained
drop
in
RPM,
can be
removed
by application
of full cartmretor heat.
Upon
regaining
the origi-
nal
RPM
(with
heat
off),
use
the minimum amount
of
heat
(by
trial and
75% POWER
65% POWER
55%
POWER
ALTITUDE
KTAS NMPG
KTAS NMPG
KTAS NMPG
Sea Level
4000 Feet
8000
Feet
114
118
122
13.5
14.O
14.5
107
111
115
14.8
15.3
15.8
100
103
106
16.1
16.6
17.1
Standard Conditions
Zero
Wind
4-16
Figure
4-3.
Cruise
Performance
Table