Aircraft design process
The aircraft design process is the engineering design process by which aircraft are designed. These depend on many factors such as customer and manufacturer demand, safety protocols, physical and economic constraints etc. For some types of aircraft the design process is regulated by national airworthiness authorities. This article deals with powered aircraft such as airplanes and helicopter designs.
Aircraft design is a compromise between many competing factors and constraints and accounts for existing designs and market requirements to produce the best aircraft.
The design process starts with the aircraft's intended purpose. Commercial airliners are designed for carrying a passenger or cargo payload, long range and greater fuel efficiency where as fighter jets are designed to perform high speed maneuvers and provide close support to ground troops. Some aircraft have specific missions, for instance, amphibious airplanes have a unique design that allows them to operate from both land and water, some fighters, like the Harrier Jump Jet, have VTOL (Vertical Take-off and Landing) ability, helicopters have the ability to hover over an area for a period of time.
The purpose may be to fit a specific requirement, e.g. as in the historical case of a British Air Ministry specification, or fill a perceived "gap in the market"; that is, a class or design of aircraft which does not yet exist, but for which there would be significant demand.
Another important factor that influences the design of the aircraft are the regulations put forth by national aviation airworthiness authorities.
Airports may also impose limits on aircraft, for instance, the maximum wingspan allowed for a conventional aircraft is 80 m to prevent collisions between aircraft while taxiing.
Budget limitations, market requirements and competition set constraints on the design process and comprise the non-technical influences on aircraft design along with environmental factors. Competition leads to companies striving for better efficiency in the design without compromising performance and incorporating new techniques and technology.
An increase in the number of aircraft also means greater carbon emissions. Environmental scientists have voiced concern over the main kinds of pollution associated with aircraft, mainly noise and emissions. Aircraft engines have been historically notorious for creating noise pollution and the expansion of airways over already congested and polluted cities have drawn heavy criticism, making it necessary to have environmental policies for aircraft noise. Noise also arises from the airframe, where the airflow directions are changed. Improved noise regulations have forced designers to create quieter engines and airframes. Emissions from aircraft include particulates, carbon dioxide (CO2), Sulfur dioxide(SO2), Carbon monoxide (CO), various oxides of nitrates and unburnt hydrocarbons. To combat the pollution, ICAO set recommendations in 1981 to control aircraft emissions. Newer, environmentally friendly fuels have been developed and the use of recyclable materials in manufacturing have helped reduce the ecological impact due to aircraft. Environmental limitations also affect airfield compatibility. Airports around the world have been built to suit the topography of the particular region. Space limitations, pavement design, runway end safety areas and the unique location of airport are some of the airport factors that influence aircraft design. However changes in aircraft design also influence airfield design as well, for instance, the recent introduction of new large aircraft (NLAs) such as the superjumbo Airbus A380, have led to airports worldwide redesigning their facilities to accommodate its large size and service requirements.
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