6.5.2 Wing Design

When the aerofoil section has been selected, the next task is to obtain the following information, which would be iterated to the final size through various design phases, as shown in Chart 2.1. Initially, all geometric details are taken from past experience (i. e., the statistical data of the aircraft class), followed by formal sizing, fine-tuned through CFD analyses and wind-tunnel testing, and finally substantiated through flight-testing (modifications are made, if required).

1. Determine the wing planform shape and its reference area. It should max­imize the aspect ratio and optimize the taper ratio. In addition, the wing ensures adequate fuel volume. At this stage, it is considered that the wing struc­tural layout can accommodate fuel capacity and movable control and lifting surfaces.

2. Determine the wing sweep, which is dependent on maximum cruise speed (see Section 3.16).

3. Determine the wing twist; a typical statistical value is 1 to 2 deg, mostly as washout (see Section 3.14).

4. Determine the wing dihedral/anhedral angle; initially, this is from the statistical data (see Section 3.14).

5. Determine high-lift devices and control areas. At first, the type is selected to satisfy the requirements at low cost. The values of its aerodynamic properties initially are taken from statistical data (see Section 3.10).

Section 6.3.2 discusses general considerations for wing design. Given here are suggestions to establish these parameters (see also Section 3.16).