should not exceed
125
RPM
on
either magneto
or
show
greater
than
50
RPM differential between magnetos.
If
there
is
a doubt concerning opera-
tion
of
the ignition system,
RPM
checks
at
higher engine speeds will usu-
ally confirm whether a deficiency exists.
An
absence
of
RPM
drop may
be
an
indication
of
faulty grounding
of
one side
of
the ignition system or should be cause for suspicion
t~at
the
magnet~
timing is
set
in
advance
of
the setting specified.
ALTERNATOR
CHECK.
Prior
to flights where verification
of
proper
alternator
and voltage
regulator operation
is
essential {such
as
night
or
instrument flights), a
positive verification can
be
made
by
loading the electrical system momen-
tarily
(3
to 5 seconds) with the optional landing light (if
so
equipped),
or
by
operating the wing flaps during the engine runup (1700 RPM). The
am-
meter
will remain within a needle width
of
zero
if
the,
alternator
and vol-
tage regulator
are
operating properly.
TAKE-OFF.
POWER
CHECK.
It
is important to check full-throttle engine operation
early
in the
tak~-off
run.
Any
signs
of
rough engine operation
or
sluggish engine
accel~r~tion
is
good cause for discontinuing the take-off.
If
this occurs,
you
are
justified in making· a thorough full-throttle, static runup before
another take-off is attempted. The engine should run smoothly and turn
approximately
2270
to
2370
·
RPM
with carburetor heat off ·and mixture
full
rich. . · · : · :
NOTE
Carburetor
heat should not be used during take-off
unless
it
is absolutely necessary for obtaining smooth
engine acceleration.
· Full-throttle runups over loose gravel
are
especi~lly
harmful to
pro-
peller tips.
When
take-offs must
be
made over a gravel surface,
it
is
very important that the throttle
be
advanced slowly. Thfs allows the
air-
plane to
start
rolling befor_e. high RPM
"is
develOped, ·and the gravel
w~ll
be
blown
back
of
the propeller
rather
than pulled into
it.
When unavoid- ·
2-13
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