Cessna 172N Operating Handbook page 109

CESSNA
MODEL 172N
SEC TIO N 7
AIRPLANE & SYSTEMS DESCRIPTIONS
INT ROD UCT ION
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.
AI R, 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
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