Torsion of Thin Walled Multi‐Cell Boxes: Formulae for Torque Distribution and Angle of Twist of Types of Boxes found in Wings, Fins, Tail Planes, etc.

THIS article is concerned with the type of multi‐cell box found in wings, fins and tail planes, etc. It does not include the effect of axial constraint applied to the box root inducing differential bending of the box spars, or the type of box whose individual cells have vastly different rates of change of cross sectional properties, i.e. a twin cell box with one cell remaining constant in area and the other tapering sharply—this type would require special analysis, in which the loads imposed on the internal ribs, due to their finite stiffness, would need investigating.