What are the structural types of the fuselage?

The fuselage can be divided into three forms according to the stress characteristics of its structural components.

① Beam type fuselage: 4 trusses bear all or most of the bending normal stress of the fuselage. The skin is thin and only bears torque and lateral shear forces. There are fewer stringers, which are used to support the skin or bear small axial forces.

This structural form is mostly used in parts of the fuselage with many flaps. For example, the front fuselage of a fighter aircraft has many large openings (cockpit cover, front landing gear hatch cover, electronic equipment bay, weapons hatch cover, etc.), and the skin cannot bear force, so a beam structure is suitable.

② Semi-monocoque fuselage: no strong trusses. The densely packed stringers and skin bear the normal bending stress. This structure is lighter in weight, and most parts of the fuselage with fewer openings adopt this structure.

③Monocoque fuselage: no stringers and stringers. In order to improve the support of the skin, dense ordinary frames are arranged along the length of the fuselage, sometimes also called dense frame structures. It is generally used in locations where the bending moment is very small and there are no large openings. Some light aircraft use monocoque fuselages for ease of manufacturing.

Rigid wing structure

Rigid wings are still the wing structure of most aircraft. Modern aircraft wings are commonly made of aluminum alloy and magnesium alloy materials. There are spar and stringers inside the wing along the span direction, and ribs or partitions along the chord direction, among which the spar is the main load-bearing component. The skin is riveted to the internal structure and bears part of the load of the wing.

During flight, the aerodynamic load acting on the wing first acts on the skin and stringers, is transmitted to the wing ribs through rivets and connecting angle pieces, and then is transmitted from the wing ribs to the wing spars. And finally passed to the fuselage through the wing spars. Inspection ports, oil drain ports and aircraft jacking seats are provided at appropriate locations on the lower surface of the wing. In order to better remove accumulated water, there is also a drain port on the lower surface of the wing.