ottom of the airframe was used as the landing gear. Later on the years, due to the need for greater strength and better performance, an enclosed, box-like fuselage was developed. It is also known as a truss. It not only increased lift and decreased drag, but it also provided protection for the pilot, passengers, and the space for cargo.WingsThe structure of a typical wing is composed of a spar-and-rib framework enclosed by a thin covering of metal sheet or treated fabric. Metal is used primarily for larger planes and fabric for smaller ones. Sometimes the wing is covered with bonded plywood or with resin-impregnated glass fiber. The spar is a beam that extends from the fuselage to the wing tip. One or more spars may be used in the wing, but usually a single spar is used. The ribs give the wing its external shape. They are arranged at right angles to the spar.The amount of wings on a plane varies. A single-winged plane is known as a monoplane. The monoplane made its appearance in the first decade of powered flight. In early airplane construction there was the use of two wings on a plane, which is called a biplane. Multiple-wing planes have the advantage of greater lift, but the monoplane has less drag. Cantilever wings are another type. They obtain their entire strength from structural elements inside the skin.The size and shape of wings also vary, depending on specific aerodynamic of the plane. For example, the wings of most supersonic planes are really thin with a knifelike leading edge. This helps to reduce the shock of compression when the plane reaches the speed of sound.Undercarriage (Landing Gear)Components of the undercarriage include the oleo strut, a hydraulic arm connecting the wheel with the wing or fuselage which absorbs the shock of landing, the retracting mechanism which raises and lowers the gear, the wheels, and the wheel brakes.The most commonly known undercarriages are: the conventional two-wheel gear and the tricycl...
