The fuselage of an aircraft is the main structure that houses the flight crew, passengers, and cargo. The term comes from the French word fusele, which means "spindle-shaped." On a commercial airliner, the fuselage, or main body, is the cigar-shaped body where the passengers and pilots are seated. On light, single-engine aircraft, the engine is usually contained in the nose, or forward-most position of the fuselage. The aircraft’s control and lift surfaces, such as the wings and tail, are bolted directly onto the fuselage in the correct positions to provide for the most stability from the aircraft.
There are several fuselage classifications, and all refer to how the frame of the body is constructed. Each design has its own advantages and disadvantages, and each is employed for the aircraft’s specific task. The four main types of fuselage structures are Box Truss, Geodetic, Monocoque, and Semi-Monocoque.
A Box Truss fuselage is by far the most popular design for small-engine light aircraft. The Box Truss design is made up of wooden planks or steel or aluminum tubes that are welded into an array of triangles, much like a bridge or crane tower. This design is popular because it is strong, easy to assemble, and very inexpensive to build.
The Geodetic body is a much more complex version of the fuselage design. Geodetic fuselages use an arrangement of flat strips of wood that are wound spirally around a main frame, sort of like weaving a basket.
A Monocoque design is one where the outer shell of the aircraft also serves as the main frame, like an exoskeleton. The design was originally created using molded plywood to form the aerodynamic structure, but has been modernized by using fiberglass and other composites to make a much lighter and stronger airplane.
The Semi-Monocoque fuselage design is the most popular design for large aircraft, including commercial airliners and military aircraft. A Semi-Monocoque design is a series of aluminum ribs, joined by strengthening bars known as "stringers" that are then covered over with an aluminum skin. An aircraft body of this type is usually built in sections and then assembled to complete the final product.
Fuselage design is ever evolving, and soon there may be a new construction type that uses complex materials to give a stronger, lighter frame while retaining the cost-effectiveness of the current designs.
The Green portion of this aircraft is the Fuselage