Cessna 172N Operating Handbook page 54

SECTION 4
NORMAL PROCEDURES
CESSNA
MODEL 172N
takeoff nrn. Any sign of rough engine operation or sluggish engine accel-
eration is good cause for discontinuing the takeoff. If this occurs, you are
justified in malcing a thorough full-throttle,
static runup before another
takeoff is attempted. The engine should run smoothly and turn approxi-
mately 2280 to 2400 RPM with carburetor heat off and mixture tull rich.
NOTE
Carhrretor heat should not be used dunng takeoff unless
it is absolutely necessary for obtaining smooth engine
acceleration.
Full-throttle
runups over loose gravel are especially harmful to pro-
peller tips. When takeoffs must be made over a gravel surface, it is very
important that the throttle be advanced slowly. This allows the airplane
to start rolling before high RPM is developed, and the gravel will be blown
back of the propeller rather than pulled into it.
When unavoidable small
dents appear in the propeller blades, they should be immediately correct-
ed as described in Section 8 under Propeller Care.
Prior to takeoff from fields above 3000 feet elevation, the mixture
shotrld be leaned to give mardmum RPM in a full-throttle,
static runup.
After full throttle is applied, adjust the throttle friction lock clock-
wise to prevent the throttle from creeping back from a maximum power
position. Similar friction lock adjustments should be made as required
in other flight conditions to maintain a fixed throttle setting.
WING Ft AP S E I TI NGS
Normal and short field takeoffs are performed with flaps up. Flap
settings greater than 10" are not approved for takeoff.
Use of 10o flaps is reserved for minimum
ground runs or for takeoff
from soft or rough fields. Use of 10o flaps allows safe use of slightty
lower takeoff speeds than with flaps up. The lower speeds result in
shortening the ground run and total distance over a 50 foot obstacle by
approximately
10Vo. However, this advantage will be lost if flaps up
speeds are used, or in high altitude takeoffs in hot weather at maxi-
mum weight where climb would be marginal with 10o flaps. Therefore,
use of 10" flaps is not recommended for takeoff over an obstacle at high
altitude in hot weather.
SH ORI FIE LD TA K E OFF
If an obstruction dictates the use of a steep climb angle, after liftoff
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