Nacelles
along a wing or stabilizer are found by giving the
number of inches between them and the centerline
In single-engine aircraft, the power plant is
station zero. Figure 2-2 shows station numbers for a
mounted in the center of the fuselage. On multiengine
typical aircraft.
aircraft, nacelles are usually used to mount the power
Station 0 (zero) is usually located at or near the
plants. The nacelle is primarily a unit that houses the
nose of the aircraft. The other fuselage stations (FS) are
engine. Nacelles are similar in shape and design for the
located at distances measured in inches aft of station 0.
same size aircraft. They vary with the size of the
On this particular aircraft, station 0 is located 93.0
aircraft. Larger aircraft require less fairing, and
inches forward of the nose. A typical nose station
therefore smaller nacelles. The structural design of a
diagram is shown in figure 2-3.
nacelle is similar to that of the fuselage. In certain cases
the nacelle is designed to transmit engine loads and
Quick access to the accessories and other
stresses to the wings through the engine mounts.
equipment carried in the fuselage is through numerous
doors, inspection panels, wheel wells, and other
Wings
openings. Servicing diagrams showing the arrangement
of equipment and the location of access doors are
The wings of an aircraft are designed to develop lift
supplied by the manufacturer in the maintenance
when they are moved through the air. The particular
instruction manuals and maintenance requirement
wing design depends upon many factors; for example,
cards for each model or type of aircraft.
size, weight, use of the aircraft, desired landing speed,
and desired rate of climb. In some aircraft, the larger
Engine Mounts
compartments of the wings are used as fuel tanks. The
wings are designated as right and left, corresponding to
Engine mounts are designed to meet particular
the right- and left-hand sides of a pilot seated in the
conditions of installations, such as their location on the
aircraft.
aircraft; methods of attachment; and size, type, and
characteristics of the engine they are intended to
The wing structures of most naval aircraft are of an
support. Although engine mounts vary widely in their
all-metal construction, usually of the cantilever design;
appearance and in the arrangement of their members,
that is, no external bracing is required. Usually wings
the basic features of their construction are similar. They
are of the stress-skin type. This means that the skin is
are usually constructed as a single unit that may be
part of the basic wing structure and carries part of the
detached quickly and easily from the remaining
loads and stresses. The internal structure is made of
structure. In many cases, they are removed as a
"spars and stringers" running spanwise, and "ribs and
complete assembly or power plant with the engine and
formers" running chordwise (leading edge to trailing
its accessories. Vibrations originating in the engine are
edge). The spars are the main structural members of the
transmitted to the aircraft structure through the engine
wing, and are often referred to as "beams."
mount.
Figure 2-3.--Typical nose station diagram.
2-3
