Aircraft structures

Aircraft structures are the structures, large and small, common or uncommon, that make up aircraft of any sort, size, or purpose.

Purpose

Structures fulfill a purpose in an aircraft, either simple or complex. Each sub-structure interfaces with the other structures in the same aircraft. Ultimately parts work together to accomplish safe flight.

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Classification

General

Aircraft structures may be classified by any of the following general categories:^{[citation needed]}

• purpose
• integration with other structures and the aircraft as a whole
• history of the structure
• problems and successes of the structure
• value to the particular aircraft
• cost
• supply
• manufacturer
• wear characteristics
• safety quotient
• popularity
• specified use
• hazards relative to the structure
• inspection challenges
• maintenance
• replacement protocol.

By type of wing

Aircraft structures may be classified by the type of wing employed, as this dictates much of the supporting structure:^{[citation needed]}

• Single planar winged
• Non-planar winged
• Biplane
• Triplane
• Ring winged
• Spanwise rotary winged
• Vertical rotary axis winged
• Morphable wing
• Flexible winged
• Rigid winged
• Flying wing
• parachutes and dogues
• Lifting bodies
• Winged man system
• Reentry-from-space vehicle

Classic aircraft structures

Classic aircraft components:^{[citation needed]}

• Wing (skins, spars, ribs)
• Fuselage (skin, bulkhead, frame, heavy frames and bulkheads)
• Control system
• Thrust system
• Empennage
• Stringers or longerons
• Spars
• Landing system
• Launching system
• Accessory structures on board

The interaction of these structural components with mechanical systems may include:^{[citation needed]}

• Undercarriage
• Ejection seat
• Powerplant

The locations of major components and systems will optimise the aircraft's weight and strength. For example in most modern military jets the heavy frame in the fuselage that supports the nose undercarriage also has the ejector seat rail mounted to it. In this way the frame has multiple functions, thus reducing weight and cost.^{[citation needed]}

The location of structural components is also important with respect to the aircraft's center-of-gravity, which has great effect on the aircraft's stability.

The materials and manufacturing techniques of the structural components are optimized during the design process. For example, stringers may be manufactured by bending sheet metal or by extrusion to optimize weight and cost, whereas a robust frame that supports a heavy component such as an engine may be a cast or machined to optimize strength.^{[citation needed]}

Regulatory requirements

Applicable national airworthiness regulations that specify structural requirements will affect the choice of materials.