Abstract
Maple seeds are a type of winged seeds that exhibit a unique spinning moving pattern during their descent. We observed in our experiment that the descent trajectories of maple seeds are not uniform, with hypotrochoid and circle being two common regular moving patterns. To explore the underlying physical mechanisms, we constructed a low-speed, vertical, open-type wind tunnel combined with motion capture cameras. A set of simplified six-degree-of-freedom equations for the maple seed model (MSM) was derived based on blade element theory. Building upon this theoretical framework, we implemented a novel numerical method within Simulink to simulate the complete descent process of the maple seed model. Both simulation and experimental results indicate that mass distribution is the dominant factor influencing the flight patterns of maple seeds. The experiments show that when the angle between the third principal inertia axis and the wing span axis is less than 3.25 degrees, the maple seed model rotates around a fixed axis, resulting in a circular trajectory from a top-down view. When the angle exceeds 3.25 degrees, the moving pattern transitions to a hypotrochoid. This finding can be applied to the structural design and flight control of biomimetic aircraft.