Design of the Grand Touring Sports Car Wing

Abstract

This study evaluated the adaptation of natural laminar flow airfoils for Grand Touring (GT) sports car racing and the influence of wing geometry and flow control devices on rear-wing aerodynamics. The mean camber lines for the National Advisory Committee for Aeronautics (NACA) 651-412 and National Aeronautics and Space Administration (NASA) LS(1)-0413 airfoils were calculated. Numerical analysis was conducted using thin-airfoil theory and finite-wing theory. Airfoil variables included zero-lift angle of attack and centre-of-pressure location. Wing variables encompassed induced and effective angles of attack, lift and drag coefficients, and lift-to-drag ratio. Modelling consisted of variations in wing aspect ratio and the integration of end plates and a Gurney flap. A tapered rectangular planform is quasi-elliptical and attains near-unity Oswald efficiency. The NASA LS(1)-0413 airfoil is stall resistant and produces high downforce at the expense of extra drag because of factors related to camber, profile thickness, leading edge radius, and concave pressure recovery. The wing should be set at an incidence above that for best lift-to-drag ratio. The NACA 651-412 airfoil is aerodynamically more efficient but produces less downforce and may be used as a stabilizer. Augmented aspect ratio, end plates, and a Gurney flap enhance wing aerodynamics via flow control and modified downwash configuration. The analysis suggests that a tapered LS(1)-0413 wing of 5.56 aspect ratio fitted with end plates and a Gurney flap, set at high incidence, is an appealing single-element arrangement for applications in Grand Touring sports car engineering.

Design of the Grand Touring sports car wing: geometric and aerodynamic twist

“…The α L 0 , is −3° and −4° for the 65 1 -412 and LS(1)-0413 airfoils, respectively. 16–18 Both airfoils exhibit extensive laminar flow and posses desirable aerodynamic properties. 15,18 The small-radius leading edge of the 65 1 -412 makes this airfoil aerodynamically efficient at low incidence.…”

“…15,18 The small-radius leading edge of the 65 1 -412 makes this airfoil aerodynamically efficient at low incidence. 16,17 The LS(1)-0413 airfoil uses a concave pressure recovery that yields high downforce, is stall resistant and can be set above the angle of attack, α , for the best downforce-to-drag ratio, − C L / C D . 17,18 Both airfoils are only slightly cambered and, therefore, are suitable for the restricted wing dimensions specified by the FIA.…”

“…17,18 Both airfoils are only slightly cambered and, therefore, are suitable for the restricted wing dimensions specified by the FIA. 5,17…”

“…16,17 The LS(1)-0413 airfoil uses a concave pressure recovery that yields high downforce, is stall resistant and can be set above the angle of attack, a, for the best downforce-to-drag ratio, ÀC L =C D . 17,18 Both airfoils are only slightly cambered and, therefore, are suitable for the restricted wing dimensions specified by the FIA. 5,17 Baseline straight inverted wings with constituent 65 1 -412 and LS(1)-0413 airfoils and linear taper were designed using CAD (Figure 2), with the following geometry and aerodynamic efficiency (based on previous work 17 ): b = 1900 mm, chord c at the wing mid-span, c r = 360 mm, and at the wing tip, c t = 324 mm, taper ratio, R T = 0.90, aspect ratio, AR = 5.56, planform area, S = 0.65 m 2 , induced drag efficiency factor, d, and lift efficiency factor, t = 0.050, and Oswald efficiency factor, e = 0.95.…”

“…The GeoTwisted LS(1)-0413 B and GeoAeroTwisted B wings concentrate the upwash at the mid-span and may thus present a narrower wake that deters pursuing cars from drafting in close proximity to the leading car. 13,14 Spanwise ÀC L and C Di distributions Use of the LS(1)-0413 airfoil for wing construction results in higher downforce primarily due to the larger leading edge radius and 1% greater thickness than in the 65 1 -412 airfoil; [16][17][18] however, such geometric features of the LS(1)-0413 airfoil augment induced drag ( Figure 6). Straight wings yield an elliptical ÀC L distribution, linear development of C Di along b and zero induced drag at the mid-span station.…”