Textron Cessna 172R, Pilot Operating Handbook

Page: 155 / 500

CESSNA
MODEL
172R
SECTION 5
PERFORMANCE
Total distance
to
clear a
50-foot obstacle,
zero
wind
Decrease
in
total distance
(2290 feet X
13%)
2290
-298
Corrected total distance
to
clear 50-foot obstacle
1
992 Feet
CRUISE
The cruising altitude should be selected based
on
a
consideration of trip length, winds aloft, and the airplane's
performance. A typical cruising altitude and the expected wind
enroute
have
been given for
this
sample
problem. However, the
power setting selection for cruise must be determined based on
several
considerations.
These include the cruise performance
characteristics presented in Figure
5-8,
the range profile
chart
presented in Figure 5-9, and the endurance profile chart
presented
in Figure 5-10.
The relationship between power and range is illustrated by the
range
profile chart.
Considerable fuel
savings and longer range
result when lower power settings are
used. For this sample
problem,
a
cruise
power
of approximately 65% will be used.
The cruise
performance
chart, Figure
5-8,
is entered
at
6000 feet
pressure altitude
and 20°C above standard
temperature.
Thesel
values
most nearly correspond
to
the planned altitude and
expected
temperature
conditions. The engine
speed
chosen
is 2200 RPM,
which
results in
the
following:
Power
True airspeed
Cruise fuel flow
64%
1 09
Knots
7.3 GPH
Revision 7
5-5
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