Abstract:

ESDU 70011 presents data for the lift-curve slope and aerodynamic centre position for wings with straight leading- and trailing-edges and streamwise tips in subsonic flow. The data were derived from lifting-surface theory and are presented in carpet form for βA up to 12, A tanΛ _½ up to 6 and taper ratio (λ) from 0 to 1, where A is aspect ratio, β is (1 - M²)^½ where M is Mach number, and Λ_½ is the half-chord sweep. The data can be applied to other than straight-tapered planforms by means of the equivalent wing planform concept (ESDU 76003 or ESDU 76015). Comparisons with a wide range of test data indicate that the lift-curve slope of wings on wing-body combinations is predicted to within about 5% and that aerodynamic centre position is predicted generally to within 0.03 of the aerodynamic mean chord.

A computer program of the method (ESDUpac A7011) is provided and includes an extension to cover wings with modestly swept forward half-chord lines.

For information, an improved form of the Helmbold-Diederich equation for wing lift-curve slope is given which provides predictions largely within ±2% of the values obtained from this Data Item for βA ≥ 1.5.