aircraft is in flight, lift forces act upward against the
wings, tending to bend them upward. The wings are
prevented from folding over the fuselage by the
resisting strength of the wing structure. The bending
action creates a tension stress on the bottom of the
wings and a compression stress on the top of the wings.
Q4-1.
The resistance to pulling apart or stretching
produced by two forces pulling in opposite
directions along the same straight lines is
defined by what term?
Q4-2.
The resistance to crushing produced by two
forces pushing toward each other in the same
straight line is defined by what term?
Q4-3.
Define the term shear as it relates to an
aircraft structure.
Q4-4.
Define the term bending.
Q4-5.
Define the term torsion.
CONSTRUCTION MATERIALS
LEARNING OBJECTIVE:
Identify the
various types of metallic and nonmetallic
materials used in aircraft construction.
An aircraft must be constructed of materials that
are both light and strong. Early aircraft were made of
wood. Lightweight metal alloys with a strength greater
than wood were developed and used on later aircraft.
Materials currently used in aircraft construction are
classified as either metallic materials or nonmetallic
materials.
4-3
TORSIONAL
STRESS
PROPELLER
ROTATION
ANfO4O2
Figure 4-2.—Engine torque creates torsion stress in aircraft fuselages.
TENSION
ANf0403
Figure 4-3.—Bending action occurring during carrier landing.
