Analysis on stability and structure computation of helicopter with slung-load

Computing method is given of geometric structure of slung-load for specially designated flight mission.Using this method, the geometry and internal force of slung rope were estimated. The influence of velocity and slung weight on geometry of slung-load was analyzed. An improvement of some existing helicopter flight dynamical model with slung-load was presented by taking geometry and detailed structure of this specific slung into consideration, and the trim state had been calculated, with the result meets existing conclusion perfectly. The equilibrium and stability property of various velocities and slung parameters were computed and analyzed. The result tells that, for helicopter with slung-load, the increment of flight velocity can improve the instability of spiral mode, however, make periodic mode worse on both longitude and lateral.