In figure 1 31a the cross section of a wing rib with

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In Figure 1-31A, the cross-section of a wing rib with a truss-type web is illustrated. The dark rectangular sections are the front and rear wing spars. Note that to reinforce the truss, gussets are used. In Figure 1-31B, a trussweb rib is shown with a continuous gusset. It provides greater support throughout the entire rib with very little additional weight. A continuous gusset stiffens the cap strip in the plane of the rib. This aids in preventing buckling and helps to obtain better rib/skin joints where nail-gluing is used. Such a rib canresist the driving force of nails better than the other types.
Wing skinOften the wing skin is designed to carry part of the flight and ground loads in conjunction with the spars and ribs. Called a stressed –skin design.Fig 1-35 shows one design.Fig 1-34 show a removable wing tip. One reason is the vulnerability to damage from ground handling and taxiing. Note also the access panel
StructuresWing Construction Truss-type
Drag and anti-drag wires may also be found in a wing. In Figure 1-32, they areshown crisscrossed between the spars to form a truss to resist forces acting on the wing in the direction of the wing chord. These tension wires are also referred to as tie rods. The wire designed to resist the backward forces is called a drag wire.The anti-drag wire resists the forward forces in the chorddirection. Figure 1-32 illustrates the structural componentsof a basic wood wing.
drag wire and anti –drag wire
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Wing Construction (continued)Upper and lower cap strips on the forward D section spar allow better conformity to the airfoil profile and the surface needed to apply sheeting to wrap the leading edge. This construction method is typical of many aircraft produced in the 1940s including the Piper Cub.
Cap stripsAdd some strengthCan be metal or woodRun length wise or chord over the ribs.Provides a surface to attach the skin or fabric.
Cap strips over the ribs
Wooden wing construction (continued)
Wooden wing construction(CONTINUED)
Wing Construction (continued)Since the end grain of glue joints have very little strength, each intersection on cap strip and cross member has a gusset of then wood glued to the strips of wood to carry the stresses from one strip to the other.
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Metal wingsMetal wings may be built up by riveting together cap strips and cross members.Made of thin sheets of aluminum alloy or pressed from hydro press.The most critical part is the front end or leading edge.Many wings have nose ribs or false ribs, that extend from the front spar forward and are placed between each of the full length former ribs.A sheet of thin aluminum alloy is wrapped around the leading edge so that the fabric will conform to the shape of the ribs.Trailing edge is formed of aluminum and tides the back end of the ribs together.

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