Free-Stream Characteristics of A Family of Low-Aspect-Ratio, All-Movable Control Surfaces for Application to Ship Design

Abstract : The free-stream characteristics of a family of low-aspect ratio, all-movable control surfaces are presented. These characteristics-i.e., force and moment coefficients, and chordwise and spanwise center of pressure locations - are plotted as functions of the angle of attack for each surface at various Reynolds numbers in both the ahead and the astern conditions. Investigations were made of the following: three aspects ratios 1, 2, and 3; five section shapes, two tip shapes, faired and square; and three sweep angles. Cross-plots were made to assess the effects of these parameters, and semi-empirical equations for the force and moment coefficients suitable for design applications are presented. Also included is a design technique for computing the control surface shaft torque.