Aircraft fairing

Aircraft fairing
The wing root of a simple aircraft, an American Aviation AA-1 Yankee, showing a wing root fairing.

A fairing is a structure whose primary function is to produce a smooth outline and reduce drag.^[1]

These structures are covers for gaps and spaces between parts of an aircraft to reduce form drag and interference drag, and to improve appearance.^{[citation needed]}

A cockpit fairing or "pod" with a windshield on a P&M GT450 ultralight trike.

Spats on a Cessna Skylane 182T

An aircraft wheel fairing, commonly called a wheel pant or spat or, by some manufacturers, a speed fairing.

Types

On aircraft, fairings are commonly found on:

Cockpit fairing

Also called a "cockpit pod", it protects the crew on ultralight trikes. Commonly made from fiberglass, it many also incorporate a windshield.^[2]

Elevator and horizontal stabilizer tips

Elevator and stabilizer tips fairings smooth out airflow at the tips.^{[citation needed]}

Engine cowlings

Engine cowlings reduce parasitic drag by reducing the surface area, having a smooth surface and thus leading to laminar flow, and having a nose cone shape, which prevents early flow separation. The inlet and the nozzle in combination lead to an isotropic speed reduction around the cooling fins and due to the speed-squared law to a reduction in cooling drag.^{[citation needed]}

Fin and rudder tips

Fin and rudder tip fairings reduce turbulence at the tips.^{[citation needed]}

Fixed landing gear junctions

Landing gear fairings reduce drag at these junctions.^{[citation needed]}

Flap track fairings

Most jet airliners have a cruising speed between Mach 0.8 and 0.85. For aircraft operating in the transonic regime (about Mach 0.8–1.2), wave drag can be minimized by having a cross-sectional area which changes smoothly along the length of the aircraft. This is known as the area rule. On subsonic aircraft such as jet airliners, this can be achieved by the addition of smooth pods on the trailing edges of the wings. These pods are known as anti-shock bodies, Küchemann Carrots, or flap track fairings, as they enclose the mechanisms for deploying the wing flaps.^[3]

Spinner

To cover and streamline the propeller hub.^[4][5]

Strut-to-wing and strut-to-fuselage junctions

Strut end fairings reduce drag at these junctions.^{[citation needed]}

Tail cones

Tail cones reduce the form drag of the fuselage, by recovering the pressure behind it. For the design speed they add no friction drag.^{[citation needed]}

Wing root

Wing roots are often faired to reduce interference drag between the wing and the fuselage. On top and below the wing it consists of small rounded edge to reduce the surface and such friction drag. At the leading and trailing edge it consists of much larger taper and smooths out the pressure differences: High pressure at the leading and trailing edge, low pressure on top of the wing and around the fuselage.^{[citation needed]}

British Airways Boeing 757-200 landing. The flap track fairings are the canoe-shaped fairings that protect and streamline the flap operating mechanisms.

Wing tips

Wing tips are often formed as complex shapes to reduce vortex generation and so also drag, especially at low speed.^[6]

Wheels on fixed gear aircraft

Wheel fairings are often called "wheel pants", "speed fairings" or, in the UK, "wheel spats". These fairings are a trade-off in advantages, as they increase the frontal and surface area, but also provide a smooth surface, a faired nose and tail for laminar flow, in an attempt to reduce the turbulence created by the round wheel and its associated gear legs and brakes. They also have the important function of preventing mud and stones from being thrown upwards against the wings or fuselage, or into the propeller on a pusher craft.^[4]

See also

• Bicycle fairing
• Motorcycle fairing
• Payload fairing

References