Effectiveness of Wing Twist Morphing in Roll Control

This paper is focused on numerical investigations that analyze the advantages obtained from high-aspect-ratio wings with unconventional roll control strategies based on wing twist morphing. A sailplane, the G103-B, produced by the GROB Werke company, was chosen as the reference aircraft for the analyses. For confidentiality reasons, the data disclosed by the builder covered only general properties such as the main dimensions, the lifting surface airfoils and attitudes, the characteristic speeds and a rough mass budget. As a consequence of this, “reverse-engineering” was considered necessary to define a reasonable wing structural layout that enabled the analysis of the elastic-aircraft roll dynamics. A preliminary sizing of the wing structure was addressed using CS-22 airworthiness requirements and by adopting fast, elementary approaches that are well known in the literature. The estimated structural arrangement, which was verified using a finite element analysis, was then used to generate the aircraft dynamic model. The elastic-aircraft roll dynamics were first investigated with regard to conventional aileron-based control. Extra modes simulating controlled twist distributions along the wing span were added into the aircraft modal base and their effects on the aircraft roll dynamics were analyzed. The conventional (aileron-based) and the unconventional (wing twist morphing) roll control strategies were compared from the aerodynamic and the aeroelastic standpoints, and the benefits achieved with the unconventional strategy are summarized.