Longitudinal Flight Performance Analysis ofParafoil-payload Systems
2015, 35 (2):
Flight performance of parafoil-payload systems is not only dependent on the aerodynamic characteristics of the parafoil itself, but also closely related to the system parameters such as rigging angle, rope length, drag force characteristics of the payloads and wing loads. The longitudinal flight dynamic equations of a parafoil-payload system were developed by adopting Lagrange equations and used to compute the flight response of the parafoil-payload system. With the aerodynamic characteristics of the parafoil given, the effects of the system parameters and opening state on longitudinal flight performance were discussed. The results show that only the rigging angle is within 0°~20°, the parafoil-payload system can reach a steady state of glide. Furthermore, the rigging angle within 4°~6° corresponds to two steady states of glide, which is dependent on the opening pitching angle and the opening velocity of the system. Increasing the rope length will make the system static stability increased. The more the drag force characteristics of the payload, the more the glide angle of the parafoil-payload system. With the drag force characteristics of the payload increased 6m2, the glide angle of the system increases about 15°, while the attack angle decreases less than 1°.In addition, wing loads have significant influence on the flight speed of the system. The speed of a parafoil-payload system is increased with the increase of wing loads and the square of the speed is proportional to the mass of the payload. These conclusions can provide theoretical guidance for practical application of parafoil-payload systems.
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