in the fuselage in appearance and as strengthening devices. Whenever
frame assemblies are used to separate one area from another, they are
circular or disc-shaped, reinforced, and equipped with doors or other
means of access, and are then called bulkheads.
Channel members, hat-shaped sections, and built-up assemblies are
inserted to give additional strength.
Station webs are built-up
assemblies located at various points to attach fittings or external
parts, such as empennage surface fittings, engine mounts, wing
Reinforced Shell Construction.
Stringers and longerons are the main lengthwise members in fuselage
structures. Notice in Figure 1-5 that the longeron is a fairly heavy
Usually, several of these run the whole length of the
The stringers are smaller and lighter, and are used
primarily for giving shape to the attached skin.