Wing root

Last updated

The wing root of a simple aircraft, an American Aviation AA-1 Yankee, showing a wing root fairing WingRoot01.jpg
The wing root of a simple aircraft, an American Aviation AA-1 Yankee, showing a wing root fairing

The wing root is the part of the wing on a fixed-wing aircraft or winged-spaceship that is closest to the fuselage, [1] and is the junction of the wing with the fuselage (not with a nacelle or any other body). The term is also used for the junction of the wing with the opposite wing, ie on the fuselage centerline, as with the upper wing of a biplane. [2] The opposite end of a wing from the wing root is the wing tip.

The aerodynamic properties of the overall aircraft can be greatly impacted by the shaping and other design choices of the wing root. [3] During both normal flight and landings, the wing root of an aircraft would be typically subjected to the highest bending forces through the aircraft. As a means of reducing interference drag between the wing and the fuselage, the use of fairings (often referred to as "wing fillets") became commonplace during the first half of the twentieth century; [4] [5] the use of wing root fairings has been credited with achieving more favourable flight characteristics at both high and low speeds. [6] Furthermore, various other innovations and approaches have been developed to influence/control airflow in the vicinity of the wing root to achieve more favourable performance. [7] Various calculating methods for designed an optimal wing root of an aircraft have been devised. [8] [9]

Fatigue has been recognised as a critical life-limiting factor associated with the wing root, which will eventually lead to catastrophic failure if not monitored. [10] Accordingly, it is commonplace within an aircraft's maintenance regime to mandate periodic assessments of the wing root to check for fatigue cracking and other signs of strain. For this purpose, the use of appropriately-applied strain gauges has become widespread, although alternative methods of detection have also been used. [11] [12]

In the case of hypersonic aircraft, the wing root is judged to be a critical structural areas in terms of its heat migration and dissipation properties. [13]

See also

Related Research Articles

<span class="mw-page-title-main">Aircraft</span> Vehicle or machine that is able to fly by gaining support from the air

An aircraft is a vehicle that is able to fly by gaining support from the air. It counters the force of gravity by using either static lift or the dynamic lift of an airfoil, or, in a few cases, direct downward thrust from its engines. Common examples of aircraft include airplanes, helicopters, airships, gliders, paramotors, and hot air balloons.

<span class="mw-page-title-main">Area rule</span> Aerodynamic concept

The Whitcomb area rule, named after NACA engineer Richard Whitcomb and also called the transonic area rule, is a design procedure used to reduce an aircraft's drag at transonic speeds which occur between about Mach 0.75 and 1.2. For supersonic speeds a different procedure called the supersonic area rule, developed by NACA aerodynamicist Robert Jones, is used.

<span class="mw-page-title-main">Waverider</span> Hypersonic aircraft design

A waverider is a hypersonic aircraft design that improves its supersonic lift-to-drag ratio by using the shock waves being generated by its own flight as a lifting surface, a phenomenon known as compression lift.

<span class="mw-page-title-main">Leading-edge extension</span> Anti-stall control surface on aircraft

A leading-edge extension (LEX) is a small extension to an aircraft wing surface, forward of the leading edge. The primary reason for adding an extension is to improve the airflow at high angles of attack and low airspeeds, to improve handling and delay the stall. A dog tooth can also improve airflow and reduce drag at higher speeds.

<span class="mw-page-title-main">Swept wing</span> Plane wing that angles backwards or forwards

A swept wing is a wing that angles either backward or occasionally forward from its root rather than in a straight sideways direction.

<span class="mw-page-title-main">Lift-to-drag ratio</span> Measure of aerodynamic efficiency

In aerodynamics, the lift-to-drag ratio is the lift generated by an aerodynamic body such as an aerofoil or aircraft, divided by the aerodynamic drag caused by moving through air. It describes the aerodynamic efficiency under given flight conditions. The L/D ratio for any given body will vary according to these flight conditions.

<span class="mw-page-title-main">Fatigue (material)</span> Initiation and propagation of cracks in a material due to cyclic loading

In materials science, fatigue is the initiation and propagation of cracks in a material due to cyclic loading. Once a fatigue crack has initiated, it grows a small amount with each loading cycle, typically producing striations on some parts of the fracture surface. The crack will continue to grow until it reaches a critical size, which occurs when the stress intensity factor of the crack exceeds the fracture toughness of the material, producing rapid propagation and typically complete fracture of the structure.

<span class="mw-page-title-main">High-lift device</span> Wing surface area adjuster, typically for shortening take-off and landing

In aircraft design and aerospace engineering, a high-lift device is a component or mechanism on an aircraft's wing that increases the amount of lift produced by the wing. The device may be a fixed component, or a movable mechanism which is deployed when required. Common movable high-lift devices include wing flaps and slats. Fixed devices include leading-edge slots, leading edge root extensions, and boundary layer control systems.

<span class="mw-page-title-main">Airplane</span> Powered, flying vehicle with wings

An airplane, or aeroplane, informally plane, is a fixed-wing aircraft that is propelled forward by thrust from a jet engine, propeller, or rocket engine. Airplanes come in a variety of sizes, shapes, and wing configurations. The broad spectrum of uses for airplanes includes recreation, transportation of goods and people, military, and research. Worldwide, commercial aviation transports more than four billion passengers annually on airliners and transports more than 200 billion tonne-kilometers of cargo annually, which is less than 1% of the world's cargo movement. Most airplanes are flown by a pilot on board the aircraft, but some are designed to be remotely or computer-controlled such as drones.

<span class="mw-page-title-main">Aircraft fairing</span> Structure on an aircraft made to reduce drag

An aircraft fairing is a structure whose primary function is to produce a smooth outline and reduce drag.

<span class="mw-page-title-main">Vertical stabilizer</span> Aircraft component

A vertical stabilizer or tail fin is the static part of the vertical tail of an aircraft. The term is commonly applied to the assembly of both this fixed surface and one or more movable rudders hinged to it. Their role is to provide control, stability and trim in yaw. It is part of the aircraft empennage, specifically of its stabilizers.

<span class="mw-page-title-main">Blended wing body</span> Aircraft design with no clear divide between fuselage and wing

A blended wing body (BWB), also known as blended body, hybrid wing body (HWB) or a lifting aerofoil fuselage, is a fixed-wing aircraft having no clear dividing line between the wings and the main body of the craft. The aircraft has distinct wing and body structures, which are smoothly blended together with no clear dividing line. This contrasts with a flying wing, which has no distinct fuselage, and a lifting body, which has no distinct wings. A BWB design may or may not be tailless.

An adaptive compliant wing is a wing which is flexible enough for aspects of its shape to be changed in flight. Flexible wings have a number of benefits. Conventional flight control mechanisms operate using hinges, resulting in disruptions to the airflow, vortices, and in some cases, separation of the airflow. These effects contribute to the drag of the aircraft, resulting in less efficiency and higher fuel costs. Flexible aerofoils can manipulate aerodynamic forces with less disruptions to the flow, resulting in less aerodynamic drag and improved fuel economy.

Supermaneuverability is the capability of fighter aircraft to execute tactical maneuvers that are not possible with purely aerodynamic techniques. Such maneuvers can involve controlled side-slipping or angles of attack beyond maximum lift.

<span class="mw-page-title-main">Wing configuration</span> Describes the general shape and layout of an aircraft wing

The wing configuration of a fixed-wing aircraft is its arrangement of lifting and related surfaces.

The wingbox of a fixed-wing aircraft refers to the primary load-carrying structure of the wing, which forms the structural centre of the wings and also the attachment point for other wing components such as leading edge flaps, trailing edge flaps and wing-tip devices. The wingbox continues beyond the visible wing roots and interfaces with the fuselage in the centre wingbox, which forms the structural core of an aircraft.

A crack arrestor is a structural engineering device. Being typically shaped into ring or strip, and composed of a strong material, it serves to contain stress corrosion cracking or fatigue cracking, helping to prevent the catastrophic failure of a device.

<span class="mw-page-title-main">Strake (aeronautics)</span> Flight control surface

In aviation, a strake is an aerodynamic surface generally mounted on the fuselage of an aircraft to improve the flight characteristics either by controlling the airflow or by a simple stabilising effect.

<span class="mw-page-title-main">Chine (aeronautics)</span> Sharp angle in aircraft cross-sections used as control surface

In aircraft design, a chine is a longitudinal line of sharp change in the cross-section profile of the fuselage or similar body. The term chine originates in boatbuilding, where it applies to a sharp profile change in the hull of a boat. In a flying boat hull or floatplane float, the longitudinal line of sharp change in cross-section where the bottom plane meets the sidewall is an example of a chine.

<span class="mw-page-title-main">Angle of incidence (aerodynamics)</span>

On fixed-wing aircraft, the angle of incidence is the angle between the chord line of the wing where the wing is mounted to the fuselage, and a reference axis along the fuselage. The angle of incidence is fixed in the design of the aircraft, and with rare exceptions, cannot be varied in flight.


  1. Peppler, I.L.: From The Ground Up, page 9. Aviation Publishers Co. Limited, Ottawa Ontario, Twenty Seventh Revised Edition, 1996. ISBN   0-9690054-9-0
  2., p.712
  3. Ibrahim Halil Guzelbey; Yüksel Eraslan; Mehmet Hanifi Doğru (March 2019). "Effects of Taper Ratio on Aircraft Wing Aerodynamic Parameters: A Comperative Study".
  4. "US2927749A: Airfoil wing root fillet". 1956.
  5. Garrison, Peter (February 2019). "The Perfect Airplane Wing". Air & Space Magazine.
  6. "Wing Root Fairings". Retrieved June 16, 2020.
  7. "US6152404A: Apparatus for influencing a wing root airflow in an aircraft". 1997.
  8. Sobieczky, H (1998). "Configuration test cases for aircraft wing root design and optimization". Inverse Problems in Engineering Mechanics. International Symposium on Inverse Problems in Engineering Mechanics. pp. 371–380. doi:10.1016/B978-008043319-6/50043-1. ISBN   9780080433196.
  9. Large, E (March 1981). "The optimal planform, size and mass of a wing". The Aeronautical Journal. Cambridge University Press. 85 (842): 103–110.
  10. Yousefirad, Behzad (January 1, 2005). "Fatigue response of aircraft wing root joints under limit cycle oscillations". Ryerson University.
  11. Lindauer, Jason M. (June 2010). "F/A-18(A-D) Wing Root Fatigue Life Expended (FLE) Prediction without the use of Stain Gage Data" (PDF). Naval Postgraduate School. Archived (PDF) from the original on December 1, 2020.
  12. Waruna Seneviratne, John Tomblin, Gayanath Aponso, Travis Cravens, Madan Kittur and Anisur Rahman (September 2011). "Durability and Residual Strength Assessment of F/A-18 A-D Wing-Root Stepped-Lap Joint". AIAA Centennial of Naval Aviation Forum "100 Years of Achievement and Progress". Aerospace Research Centre. doi:10.2514/6.2011-7032. ISBN   978-1-62410-134-2. S2CID   111712573.{{cite book}}: CS1 maint: uses authors parameter (link)
  13. Schwarz, Arman (2014). "Experimental Study of Hypersonic Wing/Fin Root Heating at Mach 8". University of Queensland.