Study on the inflated stability and motional characteristics of vortex ring parachute canopy

The vortex ring parachute is one kind of familiar rotational parachute with high rotating speed, and its aerodynamic characteristics has some advantageous for the structure design and is widely used. The vortex ring parachute consists of four sails that joined by many parachute cords, and the plackets among the sails can afford the parachute canopy to definite convexity and gradient when it is token shape. The asymmetric aerodynamic forces and moments drive the parachute to rotate. Based on the parachute tower test, the inflated stability and its motional characteristics were studied, and the influencing rules about different configuration , and sails and joint parameters of parachute cords were gained with high-speed photographic technique and attitude memory-measuring technique. The results reveal that the ratio between the balanceable dropping velocity and the balanceable angular velocity is a constant value when the vortex ring parachute reaches the steady state, and the only approach of increasing the ratio is to enhance the aerodynamic revolving torque. In addition, the joint mode of parachute cords can improve the balanceable angular velocity to a certain extent, especially the difference between the length of the leading-edge pitch line and the trailing-edge pitch line. The results are berefit to the structure design and widely application of the vortex ring parachute.