A former is an object, such as a template, gauge or 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 semicondu ...

, which is used to form something such as a boat's

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 In mathematics, curvature is any of several strongly related concepts in geometry. Intuitively, the curvature is the amount by which a curve deviates from being a straight line, or a surface deviates from being a plane. For curves, the canonic ...

. 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 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

longeron In engineering, a longeron and stringer is the load-bearing component of a framework. The term is commonly used in connection with aircraft fuselages and automobile chassis. Longerons are used in conjunction with stringers to form structural ...

s, 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 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, in a manner similar to an egg shell. The word ''monocoque'' is a French term for "single shell". First used for boats, ...

s, 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 Strip-built, or "strip-plank epoxy", is a method of boat building. Also known as cold molding, the strip-built method is commonly used for canoes and kayaks, but also suitable for larger boats. The process involves securing narrow, flexible strip ...

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, bridge building, and architecture, 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