WITH tailless aeroplanes, all known aerodynamic control devices possess the peculiarity of not only producing moments about one axis, but of also causing secondary moments about one or both of the other axes. Horizontal controllers forming part of the wing near the tips in wings having sweepback or sweepforward, for instance, do not produce rolling moments alone, when differentially deflected they also cause yawing and pitching moments. Similarly, wingtip disk rudders operated on such wings not only produce yawing moments, but may cause rolling and even pitching moments.
Aircraft Engineering and Aerospace Technology – Emerald Publishing
Published: May 1, 1945