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6.6.3
Minor Repairs
-
TI1e lamp is
a sealed
unit
incorporating
lens,
reflector
and
filament. II
lamp
is defective it
must
be
replaced.
G.6.4
Installation
of
Landing Light -
(a)
Connect electrical
leads.
(b)
Place lamp in position and install retainer
ring and plastic
cover
.
(c)
Operate light to test
for
proper installation.
6.7
STALL-WARNING
CIRCUIT
The stall warning
system
is designed
to
afford
the pilot
both
visual and
aural
indication
of
an impend-
ing stall. It
consists of a
light
on
the instrument
panel
and a
warning horn
mounted
behind the panel,
both connected
to
a sensing
unit on the leading edge
of
the
left
outboard wing panel. The sensing
unit
con-
7ists
of
a Micro
switc
h,
actuateLI by a
s
mall detector
vane when the airflow across
the leading edge of
the
wing
approaches
a
stalling
condition. The airspeed
at which a
stall warning will
occur will
var
y,
as
does
the stalling
speed itself, with various flight conditions.
The sensing
unit is
set
to close
the
circuit
7
to
9
mph
above stalling
speed with gear and flaps
up and power
off.
The stall warning horn sounds a
constant
note,
to
be
easily
distinguishable
from
the
intermittent
note
of
the landing-gear warning horn.
6.
7
.1
Trouble Shooting
-
See
Chart
6-6,
Trouble
Shooting,
Stall-
Warning Circuit.
6. 7
.2
Adjustment -
Whenever the sensing
switch is
r eplaced,
or
repairs
or
adjustments are made
to
the
wings,
the
air-
plane must
be
test-flown
to
check
adjustment
of
the
stall warning
system. With gear
and flaps up and
power off,
the airplane
is
to
be stalled
gently,
straight
ahead, reducing
speed not
mor
e
than
one
mph
per
second.
The stall warning
indicator should
fun ction
at
7
to
9 mph
above complete stall.
II
readjustment
is
required, loosen the two screws beside
the
de-
tector vane opening
in
the
mounting
plate.
Move
the
switch
up and forward
to raise the
indication speed,
or down
and back to
lower the indication
speed.
A
rrovement
of
1/
4 inch
will shift the
indication speed
about
5
mph.
After
each
adjustment,
the
airplane
must
be
test-flown
to check the
setting.
CAUTION
The detector
vane is
heat-treated. Never
attempt
to adjust
the switch by bending the vane.
Never coat
the vane
with dope, paint
or
other
material;
such coating
will interfere with
correct
operation.
6.8
DYNAMIC
BRAKE RELAY
The
dynamic
brake
relay is
mounted
beneath
th
e
right
front seat near the landing-gear
motor.
It
forms the link between the motor and the landing-
gear control circuit,
The
relay
has
two
solenoid-
operated,
double contactors,
spring-loaded
normally
open to the motor power supply. The
solenoids
a
re
5
actuated
by
the landing-gear control
circuit.
When
the landing-gear position
switch is closed, either
"UP" or
"DOWN",
It
energizes
th!:
solenoid
of
the
cont.actor selected,
which closes
liie power contacts,
establishing
the running
circuit to the motor.
Wh
en
the
control circuit Is
opened,
either by
the landing-gear position
switch or
the
limit switch,
the
solenoid is released. The
cont.actor
returns
to
its normal position,
establishing the
dynami
c
braking
circuit
through the normally-closed
contacts
of
both
contact.ors
and a rocker-arm
switch which, when the
running
contact
is
made, selects
for braking the
motor field
opposite
the
one
used for running.
6.8.1
Testing
Dynamic Brake Relay,
"UP"
-
(a)
Jack
airplane
and
support tail
section.
(b)
Disconnect
leads at motor and turn
on
elec-
trical system.
(Tape leads to prevent grounding).
(c)
Test continuity from
main
power terminal
of
air craft
to Terminal
3
of
the dynamic-brake
relay.
(d)
Manually set
the landing gear so that both
limit
switches
a
r
e
clear and place
the landing-gear
switch
in
the
" UP"
position.
(e)
Test
from
Ter
minal 1
of the relay assembly
to
ground with
24-
volt
test
lamp;
i.f
the
"UP'
'
relay
is
making
proper
contact,
test
lamp will
light.
(f)
Turning landing-gear s
witch to
"OOWN"
ur
operating the
" UP" limit or the
s
afety switch shoula
cause the
tes
t light
to go off.
6.8.2
To Test
"
DOWN" Relay -
(a)
Repeat the
same
test
for
the
"DOWN"
relay
by placing the landing-gear switch
in the
"DOWN"
position and testing
from
Terminal 2
of
the relay
assembly to
ground. Changing
landing-gear
switch
position or actuating the down-limit switch
on the
landing
gear
should cause the light to
go
out.
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