Airframe - Cessna Hawk XP R172K Pilot Operating Handbook

SECTION 7
AIRPLANE
&
SYSTEMS DESCRIPTIONS
TABLE OF CONTENTS (Continued)
Over-Voltage Sensor and Warning Light
Circuit Breakers and Fuses . . .
Ground Service Plug Receptacle
Lighting Systems
Exterior Lighting .
Interior Lighting .
Cabin Heating, Ventilating and Defrosting System
Pitot-Static System and Instruments
Airspeed Indicator
Rate-of-Climb Indicator
Altimeter
Vacuum System and Instruments
Attitude Indicator
Directional Indicator
Suction Gage
Stall Warning System
Avionics Support Equipment
Audio Control Panel . . . .
Transmitter Selector Switch
Automatic Audio Selector Switch
Audio Selector Switches
Microphone - Headset
Static Dischargers . . . . .
7-2
CESSNA
MODEL R172I\
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Cl~SSNA
MODELR172K
SECTION 7
AIRPLANE
&
SYSTEMS DESCRIPTIONS
\
INTRODUCTION
••
This section provides description and operation of the a.irp lane and
its systems. Some equipment described herein is optional and may not
be installed in the airplane. Refer to Section 9, Supplements, for de-
t.ails of other optional systems and equipment.
AIRFRAME
The construction of the fuselage is a conventional formed sheet
metal bulkhead, stringer, and skin design referred to as semi-
monocoque. Major items of structure 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 attachment of the wing struts. Four engine mount strin-
gers 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 rib's, 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 att-
ach fittings, and are partial-span spars. Conventional hinged ailerons
and single-slotted 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 aluminum
skin joined together at the trailing edge. The flaps are constructed
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 sta-
bilizer consists of a spar, formed sheet metal ribs and reinforcements, a
wrap-around skin panel, formed
leadirig
edge skin, and a dorsal. The
rudder is constructed 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 ground 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 stiffeners, center, left, and right wrap-around skin
panels, and formed leading edge skins. The horizontal stabilizer also
contains the elevator trim tab actuator. Construction of the elevator
7-3