Cessna 172 1964 Ownersmanual page 37

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oper~tional data
The Operational Data sllown on tile following pages are compiled from
actuartests with airplane and engine in good condition and using average
piloting·lechnique and best power mixture. You will find tllis data a valu-
able aid when planning your fligllts. However, inasmucll as tile number of
variables included precludes great accuracy, an ample fuel reserve should
be provided. Tile range performance shown makes no allowance for wind,
navigational error, pilot technique, warm-up, take-off, climb, etc. All
of tllese factors must be considered wllen estimating reserve fuel.
A power setting selected from the range charts usually will be more
efficient than a random setting, since it will permit you to estimate your
fuel consumption more accurately. You will find that using the charts and
your Power Computer will pay dividends in overall efficiency.
Range and endurance figures shown in the cllarts are based on flight
test using McCauley 1Cl72/ EM 7653 propeller. Otller conditions of the
tests are shown in the cllart lleadings. Allowances for fuel reserve,
lleadwinds, take-offs, and climb, and variations in mixture leaning
tecllnique sllould be made and are in addition to those shown on the charts.
Other indeterminate variables sucll as carburetor metering-cllaracteristics,
engine and propeller conditions, and turbulence of atmosphere may account
for variations of 10% or more in maximum range.
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