fairing

A fairing is a streamlined enclosure or cover added to the exterior of a vehicle or structure to reduce aerodynamic or hydrodynamic drag and to hide or protect joints, equipment, or gaps. By smoothing transitions between surfaces, fairings lower drag, improve efficiency, and can reduce noise and exposure to the elements. They are commonly made from lightweight materials such as composites or aluminum.

In aviation, fairings cover wing roots, engine nacelles, landing gear, and other junctions between components. These shapes smooth the flow of air around complex assemblies, reducing drag and delaying flow separation, which improves fuel efficiency and stability. Fairings may also house antennas, cables, or sensors. The term also includes payload fairings in spaceflight, which protect satellites or instruments during ascent and are jettisoned when the vehicle reaches space.

In spaceflight, payload fairings shield the payload from aerodynamic loads and heating during launch. They are typically discarded once the vehicle is out of the atmosphere, revealing the payload for deployment.

On land vehicles, fairings reduce aerodynamic drag and can influence cooling and styling. Motorcycle sport bikes commonly use full fairings, while naked bikes expose the frame. Cars and trucks employ belly pans, side skirts, and underbody panels or wheel covers to smooth airflow and improve efficiency.

In maritime contexts, hull and propulsion fairings reduce drag around shafts, rudders, and propellers. Features such as bulbous bows and streamlined strakes alter water flow to lower resistance and improve fuel efficiency.

Design considerations include balancing drag reduction with weight, cost, and maintenance. Materials range from composites and carbon fiber to aluminum, and optimization often relies on wind tunnel testing or computational fluid dynamics.