Structure of aeroplanes

Structure
An aircraft is a device that is used for flight. Categories of aircraft for certification of airmen include airplane, rotorcraft, lighter-than-air, powered-lift, and glider. Most airplane structures include a fuselage, wings, an empennage, landing gear, and a powerplant.
Figure 1: Airplane components.

Fuselage
The fuselage includes the cabin and/or cockpit, which contains seatsfor the occupants and the controls for the airplane. Some aircraft utilize an open truss structure. The truss-type fuselage is constructed of steel or aluminum tubing. Strength and rigidity is achieved by welding the tubing together into a series of triangular shapes, called trusses.

Figure 2: The Warren truss.
Construction of the Warren truss features longerons, as well as diagonal and verticalweb members. To reduce weight, small airplanes generally utilize aluminum alloy tubing, which may be riveted or bolted into one piece with cross-bracing members.
Types of fuselage
Fuselage cross-linked or non-resistant coating:
The coating is not cooperating with the structure to withstand the forces acting on the fuselage. It are built according to two types of basic solutions, whichmust contain at least four major or primary beams, which sometimes extend the entire length of the fuselage:
1) Pratt Structure: The four beams are joined together by vertical and diagonal elements; they should work only in tension and are called tensors.

2) Warren Structure: Is stiffer than the previous one, is characterized by elements without incapable of supporting compression, thereforenot tensors, they are replaced by tubes.
Usually constructed with beams and diagonal elements of stainless steel tubes welded molybdenum, and in some cases with steel or light alloys or bolted.

3) Monocoque fuselage: It is a structure resistant coating, this works with the rest to provide strength to the whole. It consists of a thin hollow hull transverse or longitudinal withoutorgans. Also named to the fuselage consists of rings apart, which is fixed to the casing.

Figure 3: Monocoque fuselage design.

For the most stability achieved with the inclusion of resistant coating, this type of structure has shifted to the reticulate. Currently its use is limited to cases where openings should not be practiced.
When used appeal to the use of light alloys with the advantage of beingable to increase its section at equal weight, thereby increasing the overall stability against loads acting on the fuselage. In short, it be light but it is difficult to build, it is difficult to repair, and imposes design limitations, but does not support resistant strains.

As technology progressed, aircraft designers began to enclose the truss members to streamline the airplane and improveperformance it is made of lightweight metals such as aluminum. In some cases, the outside skin can support all or a major portion of the flight loads. Since no bracing members are present, the skin must be strong enough to keep the fuselage rigid.

4) Reinforced Monocoque fuselage: Coating is reinforced with vertical rings, frames. Since the coating can absorb the tensile forces but notthe compression, which can easily cause distortion, angular profiles are added differently.

5) Semi-Monocoque fuselage: The semi-Monocoque system uses a substructure to which the airplane´s skin is attached. The substructure, which consists of bulkheads and/or formers of various sizes and stringers, reinforces the stressed skin by taking some of the bending stress from the fuselage.

Figure 4:Semi-Monocoque construction.

6) Geodetic Fuselage: Is a lattice structure representing minimum longitude lines on a curved surface, so that all tensile stress which tends to flatten the curvature of the surface is balanced by a compressive stress, and as all members are bound together, the structure is balanced at every intersection, applying a torque or longitudinal members suffer traction,...