Stresses in Single-Spar Wing Constructions with Incompletely Built-Up Ribs*

The constructional elements of single-spar wing structures are main spars, torsion tubes, ribs, and auxiliary spars. The ribs, which generally extend over the entire wing section, are for the purpose of stiffening the torsion tubes and taking up the forces in the torsion tubes and in the main spar. Mounted structures in the wing, engine, and landing gear often make it necessary to build up only one-half of the wing cross section completely with flanges and webs as a flexural supporting member. The other half of section is then omitted entirely or only the flanges are retained.