A numerical method is developed to calculate the aerodynamic forces of scissors tail-rotor in forward flight.In the present method,the three dimensional unsteady Navier-Stokes equations are used as control equations,which are discretized by low dissipation Roe scheme and implicit LU-SGS scheme in space and time directions respectively.Besides,the dual-time stepping method is employed to simulate the un-steady phenomenon of the scissors tail-rotor in forward flight,and moving embedded grid technology is ap-plied to account for rigid blade motion in rotation.Based on the present method,calculations on the aerody-namic performance for the Lynx helicopter tail-rotor in hover are firstly performed to show the capability of the present model in predicting aerodynamic performance of the tail-rotor.Then,simulations for the aerody-namic loads of Helishape 7A rotor are conducted to verify the effectiveness of the numerical method in calcu-lating the aerodynamic forces for forward flight rotors.Meanwhile,calculations on the aerodynamic forces for the scissors tail-rotor in forward flight are performed,and the effects of configuration parameters on the aerodynamic force of scissors rotor are analyzed.The calculated results indicate that,in forward flight,the average thrust of scissors tail-rotor is higher than that of the conventional one with the same blade pitch,and the scissors tail-rotor will suffer more serious BVI than the conventional one in the azimuthal angle range of 90°~180°-270°.%建立了一个适用于计算剪刀式尾桨前飞状态气动力的数值方法。在该方法中，采用惯性坐标系下的非定常 Navier-Stokes 方程作为主控方程，使用低数值耗散的 Roe 格式进行空间离散，并应用高效的隐式 LU-SGS 格式进行时间推进；采用双时间法以模拟尾桨前飞时的非定常现象；使用运动嵌套网格方法以计入尾桨桨叶的旋转运动。应用建立的方法，首先对有试验数据可作对比的 Lynx 直升机尾桨悬停状态气动性能进行了计算，验证了所建立方法对尾桨气动性能计算的有效性；同时，针对 Helishape 7A 旋翼进行了前飞状态气动载荷计算，验证了该方法对旋翼（尾桨）前飞气动载荷计算的有效性。最后，对剪刀式尾桨前飞状态进行了气动力计算，并分析了构型参数对剪刀式尾桨气动力的影响。计算结果表明，前飞状态时，相同总距下剪刀式尾桨的平均拉力要大于常规尾桨，且剪刀式尾桨在90°-180°-270°方位角内的桨-涡干扰现象较常规尾桨严重。
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