Rib (aircraft)
Encyclopedia
In an aircraft
Aircraft
An aircraft is a vehicle that is able to fly by gaining support from the air, or, in general, the atmosphere of a planet. An aircraft counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines.Although...

, ribs are forming elements of the structure of a wing
Wing
A wing is an appendage with a surface that produces lift for flight or propulsion through the atmosphere, or through another gaseous or liquid fluid...

, especially in traditional construction.

By analogy with the anatomical definition of "rib
Rib
In vertebrate anatomy, ribs are the long curved bones which form the rib cage. In most vertebrates, ribs surround the chest, enabling the lungs to expand and thus facilitate breathing by expanding the chest cavity. They serve to protect the lungs, heart, and other internal organs of the thorax...

", the ribs attach to the main spar
Spar (aviation)
In a fixed-wing aircraft, the spar is often the main structural member of the wing, running spanwise at right angles to the fuselage. The spar carries flight loads and the weight of the wings whilst on the ground...

, and by being repeated at frequent intervals, form a skeletal shape for the wing. Usually ribs incorporate the airfoil
Airfoil
An airfoil or aerofoil is the shape of a wing or blade or sail as seen in cross-section....

 shape of the wing, and the skin adopts this shape when stretched over the ribs.

Type of ribs

There are several types of ribs. Form-ribs, plate-type ribs, truss ribs, closed-ribs, forged ribs and milled ribs, where form-ribs are used for light to medium loading and milled ribs are as strong as it can get.

Form-ribs are made from a sheet of metal bent into shape, such as a U-profile. This profile is placed on the skin, just like a stringer
Stringer
Stringer may refer to:* Stringer , a type of freelance journalism* Stringer * Stringer , or longeron, a strip of wood or metal to which the skin of an aircraft is fastened...

, but then in the other direction.

Plate-type ribs consist of sheet-metal, which has upturned edges and (often has) weight-saving holes cut into it.

Truss ribs are built up out of profiles that are joined together. These joints require great attention during design and manufacture. The ribs may be light or heavy in design which make them suitable for a wide range of loads.

Closed-ribs are constructed from profiles and sheet metal and are suitable for closing off sections of the wing (e.g.: the fuel tank). Here too, particular care must be taken with the joints and this type of rib is also suitable for application in a variety of loading conditions.

Forged
Forged
Forged is a book written by biblical scholar, Bart D. Ehrman which attempts to analyze the historical accuracy of the Christian Bible. The book posits that 11 or more books out of the 27 books of the Christian New Testament canon were written as certain types of forgeries related to the politics...

 ribs are manufactured using heavy press-machinery. The result is fairly rough; for more refined parts, high-pressure presses are required, which are very expensive. Forged pieces (usually) have to undergo further treatment (for smoother edges and holes). Forged ribs are used for sections where very high loads apply - near the undercarriage for example.

Milled
Grinding (abrasive cutting)
Grinding is an abrasive machining process that uses a grinding wheel as the cutting tool.A wide variety of machines are used for grinding:* Hand-cranked knife-sharpening stones * Handheld power tools such as angle grinders and die grinders...

 ribs are solid structures. They are manufactured by milling away excess material from a solid block of metal (usually using computer-controlled milling machines). The shape of these ribs is always accurately defined. Such ribs are used under similar conditions as those for forged ribs.

Ribs are made out of wood, metal, plastic, composites, foam. The wings of kite
Kite
A kite is a tethered aircraft. The necessary lift that makes the kite wing fly is generated when air flows over and under the kite's wing, producing low pressure above the wing and high pressure below it. This deflection also generates horizontal drag along the direction of the wind...

s, hang gliders, paragliders, powered kites, powered hang glider
Powered Hang Glider
A foot-launched powered hang glider , also called powered harness, nanolight, or hangmotor, is a powered hang glider harness with a motor and propeller in pusher configuration...

s, ultralights
Ultralight aviation
The term "ultralight aviation" refers to light-weight, 1- or 2-person airplanes., also called microlight aircraft in the UK, India and New Zealand...

, windmills are aircraft that have versions that use ribs to form the wing shape.

For full size and flying model aircraft
Radio-controlled aircraft
A radio-controlled aircraft is controlled remotely by a hand-held transmitter and a receiver within the craft...

wing structures that are usually made of wood, ribs can either be in one piece (forming the airfoil at that rib's "station" in the wing), or be in a three-piece format, with the rib web being the part that the one-piece rib consisted of, with capstrips for the upper and lower edging of the rib, running from the leading edge to the trailing edge, being the other two component parts.
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