Tapered and Twisted Aerofoils: An Examination of the Characteristics of a Popular Type of Wing

THE fundamental problem of aerofoil theory is to predict accurately the characteristics of wings of various sections and plan form when the former may be any function of the latter. The vortex theory of aerofoils enables us to predict the chief properties of aerofoils below the stall. We are, however, interested also in the conditions obtaining at and above the stall. In the present state of the art we are obliged to rely on wind tunnel tests. The number and variety of wings that would have to be tested in order to give us at all a comprehensive survey of the possibilities of taper, aerodynamic twist and varying section are so great that wind tunnel tests can so far only be said to have touched the fringe of the problem.