The invention relates to an aircraft comprising a transonic swept-back laminar wing, which is based on airfoils with a leading edge, wherein the swept wing and its airfoils are defined by a set of parameters comprising one or more of the parameters• leading-edge sweep angle ϕ0b,• chord length (in free-stream direction) Cb,• thickness ratio rtb andwherein the set of parameters is defined by a reference wing and its reference airfoils, which are defined by a set of reference parameters comprising one or more of the given parameters• leading-edge sweep angle ϕ0a• chord length (in free-stream direction) Ca,• thickness ratio rta andwherein the leading-edge sweep angle ϕ0a is expressed by a function of Equation 1 below ϕ0b=1u∞arc sin(2,5√ν∂u_e/∂x|_ALReCH) and wherein thickness t of the wing is expressed by a function of Equation 2 below tb=rtacacosϕ0a/cosϕ0b and wherein the thickness ratio rtb of the wing is expressed by a function of Equation 3 below rtb=tb/cbSince the effect of attachment-line contamination also depends on the sweep angle ϕ0 of the leading edge, it is postulated that the sweep angle of wing a can be reduced, if the thickness t of this wing is reduced, leading to the wing b compared to a reference wing a. However, it is important that the thickness ratio is kept constant: rt|b=rt|a.The benefit of the invention is that natural laminar flow (NLF) of current swept supercritical wings can be achieved without reduction of the transonic drag divergence Mach number Mdd. The invention avoids the application of supplementary systems on-board of the aircraft to have a Laminar Flow Control (LFC) system or a Hybrid Laminar Flow Control (HLFC) system, which would add complexity and weight to the airplane. Also avoided is the need of a Kruger flap, which shields the leading edge, but exerts an extra drag during take-off. The occurrence of isolated turbulent wedges is possible.
SWEPT QUASI-THIN SUPERCRITICAL LAMINAR WING
QUASI-DÜNNER SUPERKRITISCHER LAMINARER PFEILFLÜGEL
AILE LAMINAIRE SUPERCRITIQUE QUASI-MINCE BALAYÉE
2022-06-15
Patent
Electronic Resource
English
IPC: | B64C AEROPLANES , Flugzeuge |
Electrogasdynamic laminar flow control on a swept wing
Online Contents | 2016
|Laminar Flow Control on a Swept Wing with Distributed Roughness
British Library Conference Proceedings | 2008
|