Wing shape and dynamic twist design of bio-inspired nano air vehicles for forward flight purposes

The wing shape and kinematics of flapping wing nano air vehicles play a crucial role in the effectiveness of the system. Optimizing these design parameters allows for greater endurance during flight due to a reduction in the needed aerodynamic power. In this study, seven insects' wings are considered in order to investigate which wing shape requires less amount of aerodynamic power for forward flight missions. A strip theory model is employed and verified for two types of birds, namely, Jack Daw, and Mew Gull. Then, this aerodynamic theory is utilized to model and optimize the kinematics of the seven wings with a particular investigation on the impacts of the dynamic twist on the performance of bio-inspired nano air vehicles. Each wing is divided into strips that are individually analyzed and integrated over the full wingspan to determine the needed aerodynamic power and propulsive efficiency. The use of this modified strip theory is beneficial because it includes the unsteady aerodynamic effects and the possible change in the wings' dimensions. A parametric study is then carried out to determine the optimum wing shape and associated dynamic twist of the flapping wing nano air vehicle when considering two scenarios. In the first scenario, the wingspan for all considered seven wing shapes is considered the same. As for the second scenario, the seven wing shapes are considered with same wing surface. The results show that for same wingspan and wing surface, the bio-inspired honeybee and bumblebee wing shapes have the optimum performances, respectively. The performed analysis gives guidelines on the optimum design of flapping wing nano air vehicles for forward flight applications.