Utility helicopter design synthesison of stealth and aerodynamic configuration

Based on a conventional utility helicopter, design synthesis scheme on stealth and aerodynamic configuration was proposed. The parametric geometric model of the modified helicopter was established. And numerical simulation was performed for design analysis. In terms of electromagnetic analysis, physical optics and the method of equivalent currents were used for radar cross section (RCS) calculation. In terms of aerodynamics, the finite volume method was used by solving Navier-stokes equations to calculate the aerodynamics of fuselage in forward flight (without rotor wing). Engineering empirical equation was used to estimate aerodynamics interference of rotor wings on fuselage. The final results show that the design scheme of helicopter has a low RCS level, the aerodynamic drag of the fuselage is decreased effectively while the interference of rotor wings on fuselage is enhanced. RCS can be reduced by the appropriate selection of the tilt angle of fuselage and vertical tail, and only a relative small price should be paid for aerodynamics performance.