The optimal planform, size and mass of a wing

Extract

In the absence of a criterion for maximum wingtip deflection, the estimation of wing weight is a straightforward technical problem, for conventional planform shapes. Shear force and bending moment are integrated from the wing-tip to the wing root; using the known aerofoil shape, and the maximum allowable stress or strain, the skin thickness is determined at each station, and hence the mass of the entire wing is found.

It is safe to assume constant wing-loading per unit area along the span. If less than this constant value is used near the root, then some of this load must be transferred to stations further outboard; the bending moment at the wing-root is increased, and the skin-thickness and hence the wing weight will also be increased.