Forged Rib Essay

Register to read the introduction… This rib is also suitable for a variety of loading conditions. Forged ribs are manufactured using heavy press-machinery, and are used for sections where very high loads apply. Milled ribs are solid structures, manufactured by milling away excess material from a solid block of metal, and are also used where very high loads apply. The stringers on the skin panels run in the length of the wing, and so usually need to bridge the ribs. There are several methods for dealing with this problem. The stringers and ribs can both be uninterrupted. The stringers now run over the rib, leaving a gape between rib and skin. Rib and skin are indirectly connected, resulting in a bad shear load transfer between rib and skin. The stringers can be interrupted at the rib. Interrupting the stringer in this way certainly weakens the structure, and therefore extra strengthening material, called a doubler, is usually added. Naturally, the stringers can also interrupt the rib. The stringers now run through holes cut into the rib, which also causes inevitable weakening of the structure. The ribs also need to be supported, which is done by the spars. These are simple beams that usually have a cross-section similar to an I-beam. The spars are the most heavily loaded parts of an aircraft. They carry much more force at its root, than at the tip. Since wings will bend upwards, spars usually carry shear forces and bending moments. Aerodynamic forces not only bend the wing, they also twist it. To prevent this, the introduction of a second spar seems logical. Torsion now induces bending of the two spars, which is termed differential bending. Modern commercial aircrafts often use two-spar wings where the spars are joined by a strengthened section of skin, forming the so-called torsion-box structure. The skin in the torsion-box structure serves both as a spar-cap (to resist bending), as part of the torsion box (to resist torsion) and to transmit aerodynamic forces. Wing Functions and Attachments It is usually hard to attach the wing to the fuselage. There is usually a third piece of wing contained within the fuselage. The connection of wings and fuselage are always by way of very strong and heavy bolts. The bolts that are used must be much stronger than necessary, thereby having sufficient lifetime. Stringers are attached to the wing skin, and run span-wise. Their job is to stiffen the skin so that it does not buckle when subjected to compression loads caused by wing bending and twisting, and by loads from the aerodynamic effects of lift and control-surface movement. In most aircraft, the wing skin performs several tasks. …show more content…
It gives it the aerodynamic shape, it carries a share of the loads, it helps to carry torsional loads, it acts as fuel tanks and allows inspection and maintenance. Using the skin to carry part of the loads is called stressed skin. Almost all aircraft have their wing structure made entirely in metal, or a mixture of metal and composite. The skin may be fixed to the internal structure by rivets or bonding. The volume between the spars is often used for storing fuel. An alternative to attaching stringers to the skin for stiffness is a machined skin, in which the skin, stringers and spar flanges can be machined from a single piece of alloy, called a billet. Advantages are that less riveting is required, resulting in a smoother surface, lighter and stronger structures are possible, construction faults are less likely, less maintenance is required and easy inspection is possible. However, the costs are relatively high, and replacing parts is difficult. In commercial aircrafts usually around 25% of the aircraft’s maximum operating weight is for fuel storage. Usually most or all of the fuel is stored in the wing, which is divided into several tanks, each one usually having its own pumps. This allows fuel to be moved between tanks in flight, which changes the trim of the aircraft to minimize drag. Flaps are fitted at the trailing edges. Light aircraft usually have simple flaps or none at all. Larger aircraft have the more complex split flap or Fowler flap. Most large transport aircraft have double-slotted Fowler flaps. Leading-edge flaps, called slats, may be added to increase lift even further. Flaps and slats increase both lift and drag, both being advantageous for