Analysis of aerodynamic characteristics of helicopter biplane tailplane

Abstract

To analyze the aerodynamic characteristics of helicopter biplane tailplane, computational models for helicopter biplane tailplane and monoplane tailplane were established via CFD. The aerodynamic characteristics of different configurations of tailplanes at low speed forward flight and high angle of attack was obtained. The aerodynamic characteristics and flow characteristics of biplane/monoplane tailplane were analyzed. The mechanism of biplane tailplane to improve the longitudinal static stability at low speed forward flight and high angle of attack was investigated. The results show that the biplane tailplane can improve the helicopter pitch moment surge at low speed forward flight by restraining the rotor/tailplane interference, comparing with the monplane tailplane, the pitch moment of the biplane tailplane was reduced by about 56.8% at an advance ratio of 0.05. The stall angle of attack and maximum pitch moment of the biplane tailplane were larger, which can enhance the helicopter longitudinal static stability at high angle of attack, comparing with the monplane tailplane, the pitch moment of the biplane tailplane increased by about 60.1% at an attack angle of 20°.