Novel Airfoil Morphing Concept with Composite Material Skin

The conventional aircraft design process often involves optimizing wing geometry for a dominant flight condition, leading to compromises that result in suboptimal performance across the aircraft’s full operational envelope. Morphing wing technologies, particularly in the airfoil component, have emerged as a promising solution to enhance aircraft efficiency and adaptability across diverse flight phases. This paper reviews existing airfoil morphing concepts, particularly their limitations that need to be addressed for a viable airfoil morphing technology application. To address these shortcomings, this study introduces a novel airfoil morphing concept designed to meet critical requirements: a failsafe structure, structurally integrated actuators, fast actuation using servomotors, and a continuous skin surface. This concept executes airfoil camber and trailing-edge thickness morphing, which has the potential to be applied in small-to-medium size unmanned aerial vehicles. A prototype is manufactured and tested as a proof of concept, supported by its computational structural model. A surrogate model using the polynomial and kriging models is constructed to evaluate the most important design variables of the morphing concept in improving the aerodynamic performance of the NACA 4418 airfoil and to assess how these variables interact in the most important airfoil aerodynamic performance metrics: maximum lift coefficient, maximum lift-to-drag ratio, and pitching moment coefficient corresponding to maximum lift-to-drag ratio. The results show that it is possible to increase the maximum lift coefficient of the original airfoil up to 37.6% and the maximum lift-to-drag ratio up to 28.8%. The aerodynamic performance of the airfoil morphing concept is also compared to the performance of conventional hinged surfaces, such as ailerons and plain flaps, with equivalent deflections, and the results show that the morphing concept can achieve an increased up to 11.9% maximum lift coefficient and an increased up to 87.7% maximum lift-to-drag ratio.