The effect of area aspect ratio on the yawing moments of rudders at large angles of pitch on three fuselages

This reports presents the results of measurements made of yawing moments produced by rudder displacement for seven rudders mounted on each of three fuselages at angles of pitch of 0 degree, 8 degrees, 12 degrees, 20 degrees, 30 degrees and 40 degrees. The dimensions of the rudders were selected to cover the range of areas and aspect ratios commonly used, while the ratios of rudder area to fin area and of rudder chord to fin chord were kept approximately constant. An important result of the measurements is to show that increased aspect ratio gives increased yawing moments for a given area, provided the maximum rudder displacement does not exceed 25 degrees. If large rudder displacements are used, the effect of aspect ratio is not so great.