Wing root

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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

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  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   978-0-08-043319-6.
  9. Large, E (March 1981). "The optimal planform, size and mass of a wing". The Aeronautical Journal. Cambridge University Press. 85 (842): 103–110. doi:10.1017/S0001924000029481. S2CID   116825025.
  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; 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.
  13. Schwarz, Arman (2014). "Experimental Study of Hypersonic Wing/Fin Root Heating at Mach 8". University of Queensland.