A former is an object, such as a template,

gauge Gauge (US: , UK: or ) may refer to: Measurement * Gauge (instrument) A gauge, in science Science (from the Latin word ''scientia'', meaning "knowledge") is a systematic enterprise that Scientific method, builds and Taxonomy (general), o ...

cutting Cutting is the separation or opening of a physical object, into two or more portions, through the application of an acutely directed force. Implements commonly used for wikt:cut, cutting are the knife and saw, or in medicine and science the scal ...

cutting

die Die, as a verb, refers to death, the cessation of life. Die may also refer to: Games * Die, singular of dice, small throwable objects used for producing random numbers Manufacturing * Die (integrated circuit), a rectangular piece of a semiconduct ...

, which is used to form something such as a

boat A boat is a watercraft Watercraft, also known as water vessels or waterborne vessels, are vehicles A vehicle (from la, vehiculum) is a machine A machine is any physical system with ordered structural and functional properties. It m ...

boat

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 affin ...

. Typically, a former gives shape to a structure that may have complex

curvature In mathematics Mathematics (from Ancient Greek, Greek: ) includes the study of such topics as quantity (number theory), mathematical structure, structure (algebra), space (geometry), and calculus, change (mathematical analysis, analysis). ...

. A former may become an integral part of the finished structure, as in an aircraft

fuselage In aeronautics Aeronautics is the science or art involved with the study, design process, design, and manufacturing of air flight–capable machines, and the techniques of operating aircraft and rockets within the atmosphere. The British Roy ...

, or it may be removable, being using in the construction process and then discarded or re-used.

Aircraft formers

Here, a former is a structural member of an

aircraft An aircraft is a vehicle that is able to flight, fly by gaining support from the Atmosphere of Earth, air. It counters the force of gravity by using either Buoyancy, static lift or by using the Lift (force), dynamic lift of an airfoil, or in ...

, 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 (physiology), respiration alongside the mouth. Behind the nose are the olfactory mucosa and the Paranasal sinus, sinuses. Be ...

nose

to the

empennage The empennage ( or ), also known as the tail or tail assembly, is a structure at the rear of an aircraft that provides stability during flight, in a way similar to the feathers on an arrow.Crane, Dale: ''Dictionary of Aeronautical Terms, third ed ...

, 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

longeron In engineering Engineering is the use of scientific method, scientific principles to design and build machines, structures, and other items, including bridges, tunnels, roads, vehicles, and buildings. The discipline of engineering encompas ...

s, which support the skin of the aircraft. The "former-and-longeron" technique (also called stations and stringers) was adopted from

boat construction 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 inla ...

, and was typical of

light Light or visible light is electromagnetic radiation within the portion of the electromagnetic spectrum that is visual perception, perceived by the human eye. Visible light is usually defined as having wavelengths in the range of 400–700 nan ...

light

aircraft built until the advent of

structural skin Monocoque (), also called structural skin, is a structural system in which loads are supported by an object's external skin, similar to an egg shell. The word ''monocoque'' is a French term for "single shell". First used for boats, a true monoco ...

s, such as

fiberglass Fiberglass (American English American English (AmE, AE, AmEng, USEng, en-US), sometimes called United States English or U.S. English, is the set of varieties of the English language native to the United States. Currently, American Englis ...

and other

composite materials A composite material (also called a composition material or shortened to composite, which is the common name) is a material Material is a substance Substance may refer to: * Substance (Jainism), a term in Jain ontology to denote the base or o ...

. Many of today's light aircraft, and

homebuilt aircraft Homebuilt aircraft, also known as amateur-built aircraft or kit planes, are constructed by persons for whom this is not a professional activity. These aircraft may be constructed from "scratch", from plans, or from assembly kits.Armstrong, Kenn ...

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 Strip-built, or "strip-plank epoxy Epoxy is the family of basic components or cured A cure is a completely effective treatment for a disease. Cure, or similar, may also refer to: Places * Cure (river), a river in France * Cures, Sabinum, ...

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 Regulation and licensure in engineering is established by various jurisdictions of the world to encourage public welfare, safety, well-being and other interests of the general public and to defin ...

bridge building A bridge is a Nonbuilding structure, structure built to Span (engineering), span a physical obstacle, such as a body of water, valley, or road, without closing the way underneath. It is constructed for the purpose of providing passage over the ...

, and

architecture upright=1.45, alt=Plan d'exécution du second étage de l'hôtel de Brionne (dessin) De Cotte 2503c – Gallica 2011 (adjusted), Plan of the second floor (attic storey) of the Hôtel de Brionne in Paris – 1734. Architecture (Latin ''archi ...

, arches may be built upon a wooden former, which is removed once the

keystone Keystone or key-stone or ''variation'', may refer to: * Keystone (architecture), a central stone or other piece at the apex of an arch or vault * Keystone (cask), a fitting used in ale casks Business * Keystone Law, a full-service law firm * Digi ...

is securely in place.

References

Boat building Aircraft components {{Aviation-stub