Cessna 172N - Airframe, Flight Controls, and Instruments

CESSNA
MODEL 172N
SECTION
7
AIRPLANE
&
SYSTEMS
DESCRIPTIONS
INTRODUCTION
This
section
provides
description and
operation
of
the airplane
and
its
systems. Some
equipment
described
herein
is
optional
and
may
not
be
installed
in
the airplane.
Refer
to
Section 9,
Supplements,
for detaits
of
other optional
systems
and
equipment.
AIR,F RA
ME
The
constmction
of the
fuselage
is
a conventional
formed
sheet
metal
bulkhead,
stringer, and
skin
design referred
to
as
semi-monocoque.
Major
items
of stmcture
are
the front and rear
carry-through
spars to
which
the
wings are attached,
a
bulkhead
and
forgings
for
main
landing
gear
attachment
at
the
base of the
rear
doorposts, and
a bulkhead
with
attaching
plates
at the
base of
the
forward doorposts
for the lower
attach-
ment
of
the
wing
stmts. Four
engine
mount
stringers
are also
attached
to
the
forward doorposts and
extend forward
to the firewall.
The
externally
braced wings,
containing
the fuel
tanks,
are
con-
structed
of
a
front
and rear
spar with formed
sheet
metal
ribs,
doublers,
and
stringers.
The
entire
structure
is covered
with
aluminum
skin.
The
front
spars
are equipped
with
wing-to-fuselage
and wing-to-strut
attach
fittings.
The
aft
spars
are
equipped with
wing-to-fuselage
at-
tach fittings,
and
are
partial-span
spars.
Conventional
hinged
ailerons
and
single-slot
type
flaps
are attached
to the
trailing
edge
of
the
wings.
The
ailerons
are constructed
of a forward
spar
containing
a
balance
weight,
formed
sheet
metal
ribs and
"V"
type
corrugated
alum-
inum
skin
joined
together
at
the
trai.ling
edge.
The
flaps
are
construct-
ed
basically
the same
as the
ailerons, with
the
exception
of the
balance
weight
and
the addition of
a
formed
sheet
metal leading
edge
section.
The
empennage
(tail
assembly)
consists
of a
conventional
vertical
stabilizer,
rudder,
horizontal
stabilizer,
and
elevator.
The
vertical
stabilizer
consists
of
a spar,
formed
sheet metal ribs
and reinforcements,
a
wrap-around
skin
panel,
formed leading
edge
skin, and
a dorsal.
The
rudder
is constnrcted
of
a
formed leading
edge
skin containing
hinge
halves,
a
center
wrap-around
skin
panel,
ribs,
an aft
wrap-around
skin
panel
which
is
joined
at
the
trailing
edge
of the rudder
by a
filler
strip,
and
a
grcund
adjustable
trim
tab at
the base
of the
trailing
edge. The
top
of
the
rudder
incorporates
a leading
edge
extension
which
contains
a balance
weight.
The
horizontal
stabilizer
is
constructed
of
a
forward
and aft
spar,
ribs
and
sti-ffeners,
center,
left,
and
right
wrap-around
skin
panels,
airo
'
formed
leading edge
skins.
The horizontal
stabilizer
also
contains
the
elevator
trim
tab
actuator.
Constnrction
of the
elevator
consists
of
form-
ed
leading
edge
skins, a forward
spar,
aft channel,
ribs,
torque
tube
and
7-3