Wing root

{{Short description|Portion of aircraft wing}}

{{Use mdy dates|date=March 2023}}

{{Use American English|date=March 2023}}

File:WingRoot01.jpg, 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,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}} 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.https://archive.org/details/the-cambridge-aerospace-dictionary, p.712 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.{{cite web |url = https://www.researchgate.net/publication/328916819 |title = Effects of Taper Ratio on Aircraft Wing Aerodynamic Parameters: A Comperative{{sic|hide=y}} Study |author1=Ibrahim Halil Guzelbey |author2=Yüksel Eraslan |author3=Mehmet Hanifi Doğru |date = March 2019}} 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;{{cite web |url = https://patents.google.com/patent/US2927749A/en |title = US2927749A: Airfoil wing root fillet |date = 1956}}{{cite web |url = https://www.airspacemag.com/flight-today/perfect-airplane-wing-180971225/ |title = The Perfect Airplane Wing |publisher = Air & Space Magazine |first = Peter |last = Garrison |date = February 2019}} the use of wing root fairings has been credited with achieving more favourable flight characteristics at both high and low speeds.{{cite web |url = https://personal.utdallas.edu/~klaus/Airplane/wing_root_fairing.html |title = Wing Root Fairings |publisher = utdallas.edu |access-date = 16 June 2020}} 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.{{cite web |url = https://patents.google.com/patent/US6152404 |title = US6152404A: Apparatus for influencing a wing root airflow in an aircraft |date = 1997}} Various calculating methods for designed an optimal wing root of an aircraft have been devised.{{cite book |chapter-url = https://www.sciencedirect.com/science/article/pii/B9780080433196500431 |chapter = Configuration test cases for aircraft wing root design and optimization |publisher = International Symposium on Inverse Problems in Engineering Mechanics |first = H |last = Sobieczky |title = Inverse Problems in Engineering Mechanics |date = 1998 |pages = 371–380|doi = 10.1016/B978-008043319-6/50043-1 |isbn = 978-0-08-043319-6 }}{{cite journal |url = https://www.cambridge.org/core/journals/aeronautical-journal/article/optimal-planform-size-and-mass-of-a-wing/8FC756BF2D248BFD9AD12AED9881D0A9 |title = The optimal planform, size and mass of a wing |publisher = Cambridge University Press |volume = 85 |issue = 842 |first = E |last = Large |journal = The Aeronautical Journal |date = March 1981 |pages = 103–110|doi = 10.1017/S0001924000029481 |s2cid = 116825025 |url-access = subscription }}

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.{{cite web |url = https://digital.library.ryerson.ca/islandora/object/RULA%3A664 |title = Fatigue response of aircraft wing root joints under limit cycle oscillations |publisher = Ryerson University |last = Yousefirad |first = Behzad |date = 1 January 2005}} 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.{{cite web |url = https://apps.dtic.mil/dtic/tr/fulltext/u2/a524711.pdf |archive-url = https://web.archive.org/web/20201201154012/https://apps.dtic.mil/dtic/tr/fulltext/u2/a524711.pdf |url-status = live |archive-date = December 1, 2020 |title = F/A-18(A-D) Wing Root Fatigue Life Expended (FLE) Prediction without the use of Stain Gage Data |publisher = Naval Postgraduate School |first = Jason M. |last = Lindauer |date = June 2010}}{{cite book |chapter-url = https://arc.aiaa.org/doi/abs/10.2514/6.2011-7032 |chapter = Durability and Residual Strength Assessment of F/A-18 A-D Wing-Root Stepped-Lap Joint |author=Waruna Seneviratne |author2=John Tomblin |author3=Gayanath Aponso |author4=Travis Cravens |author5=Madan Kittur |author6=Anisur Rahman |title = AIAA Centennial of Naval Aviation Forum "100 Years of Achievement and Progress" |publisher = Aerospace Research Centre |date = September 2011|doi = 10.2514/6.2011-7032 |isbn = 978-1-62410-134-2 |s2cid = 111712573 }}

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.{{cite web |url = https://espace.library.uq.edu.au/view/UQ:347730 |title = Experimental Study of Hypersonic Wing/Fin Root Heating at Mach 8 |publisher = University of Queensland |last = Schwarz |first = Arman |date = 2014}}