Lift enhancement study and experimental verification for ornithopter

Abstract Ornithopter is a research hotspot of unmanned aerial vehicles. In this paper, an ornithopter inspired by birds is designed. The fin deflection mechanism is adopted. During the upstroke phase, the fins are passively unfolded to reduce the resistance when the wing moves upward; while during the downstroke phase, the wings are passively closed to increase the effective wing area and the resistance during the downstroke, so as to increase the lift generated by the ornithopter during the flapping process. The wingspan of the ornithopter is 1.2 meters, and its weight is 180 grams. The inner wing is designed with a cambered wing and can carry a load of 150 grams. Through the lift test experiment of the ornithopter with and without the deflection mechanism, the results show that the lift of the cambered wing is increased by 41.99% ± 2.63% compared with that of the flat wing, and the lift of the wing deflection mechanism is increased by 5.26% ± 1.47%. Indoor and outdoor flight experiments are carried out, and the ornithopter can achieve the expected flight goals with good flight performance. This study provides new insights for improving the performance of ornithopter.