Helicopter stability and control in the presence of windshear

Purpose - This paper aims to present a theoretical method for analyzing the stability and control of a hingeless helicopter in the presence of windshear. Design/rnethodology/approach - In this paper, the stability and control of a hingeless helicopter in the presence of windshear are investigated. First, the rotary wing dynamic model considered is the one of flap-pitch (including the elastic deformation of the control system)-torsion coupling. The induced velocity nonuniform distribution derived from vortex theory is taken into account. Then, as for atmospheric turbulence, the linear windshear model is used for modeling the variation of wind field. Finally, according to the calculated results of the stability characteristic roots and the control response of the helicopter, the helicopter performance in wind shear field is analyzed, and some conclusions are obtained. Findings - Some useful conclusions are obtained through sample analysis. Research limitations/implications - Although the analyses for stability and control of a hingeless helicopter in the presence of windshear could be obtained using the current method, the model of complex wind field will still be expected in future studies. Practical implications - A very useful method for analyzing helicopter stability and control. Originality/value - The proposed method is valid and available for the analysis of helicopter flight dynamics.