A former is an object, such as a template, gauge or cutting die, which is used to form something such as a

boat A boat is a watercraft of a large range of types and sizes, but generally smaller than a ship, which is distinguished by its larger size, shape, cargo or passenger capacity, or its ability to carry boats. Small boats are typically found on i ...

hull Hull may refer to: Structures * Chassis, of an armored fighting vehicle * Fuselage, of an aircraft * Hull (botany), the outer covering of seeds * Hull (watercraft), the body or frame of a ship * Submarine hull Mathematics * Affine hull, in affi ...

. Typically, a former gives shape to a structure that may have complex curvature. A former may become an integral part of the finished structure, as in an aircraft fuselage, or it may be removable, being using in the construction process and then discarded or re-used.

Aircraft formers

Formers are used in the construction of aircraft fuselage, of which a typical fuselage has a series from the

nose A nose is a protuberance in vertebrates that houses the nostrils, or nares, which receive and expel air for respiration alongside the mouth. Behind the nose are the olfactory mucosa and the sinuses. Behind the nasal cavity, air next pass ...

to the empennage, typically perpendicular to the longitudinal axis of the aircraft. The primary purpose of formers is to establish the shape of the fuselage and reduce the column length of stringers to prevent instability. Formers are typically attached to longerons, which support the skin of the aircraft. The "former-and-longeron" technique (also called stations and stringers) was adopted from boat construction, and was typical of

light Light or visible light is electromagnetic radiation that can be perceived by the human eye. Visible light is usually defined as having wavelengths in the range of 400–700 nanometres (nm), corresponding to frequencies of 750–420 te ...

aircraft built until the advent of structural skins, such as fiberglass and other composite materials. Many of today's light aircraft, and homebuilt aircraft in particular, are still designed in this way.

Disposable formers

A former may instead be a temporary shape over which a structure is built, the former subsequently being discarded in whole or part, as follows: * Strip-built boat construction uses formers over which thin plank strips are applied and glued.Boat building with strip planking
/ref> in some cases, some of the formers may be incorporated as structural ribs. * In

civil engineering Civil engineering is a professional engineering discipline that deals with the design, construction, and maintenance of the physical and naturally built environment, including public works such as roads, bridges, canals, dams, airports, sewa ...

, bridge building, and

architecture Architecture is the art and technique of designing and building, as distinguished from the skills associated with construction. It is both the process and the product of sketching, conceiving, planning, designing, and constructing buildings ...

, arches may be built upon a wooden former, which is removed once the keystone is securely in place.

References

Boat building Aircraft components {{Aviation-stub