可变弯尾飞行器空间螺旋机动的实现

可变弯尾飞行器具有气动控制独特、机动范围可调等特点,是高超声速飞行器实现机动飞行的有效途径。可变弯尾飞行器不仅可以实现射面内的拉起和下压机动,还可以利用入轨时起旋与尾部的上下摆动实现空间的螺旋机动,并且可以在不起旋时利用可变的弯尾部分进行绕球铰的空间转动使飞行器产生空间螺旋运动。通过气动力工程预测方法与飞行器六自由度弹道的耦合计算,研究了此类飞行器在再入过程中的螺旋运动、稳定性及飞行特性。

Simulation of spiral maneuvering for a variable-bend-tail vehicle

Variable-bend-tail vehicle is one of the possible approaches for hypersonic reentry maneuver,because of its unique control mechanism and adjustable maneuverability.This vehicle can realize not only pitch up/down maneuvering in its inject plane,but may also achieve spatial spiral maneuvering via two kinds of control laws.One method is the combination of initial-rolling and up/down deflection,the initial rolling angular speed is the key issue for the spiral radius which represents the maneuvering ability,whereas overall lifting-rolling can not pull the trajectory up,and the losing of kinetic energy may be so high as to make the landing speed under a reasonable range,simultaneously the maneuvering distances in both longitudinal and transversal directions are generally limited.The other spiral control law is roll-and-swing method as follows: firstly pull the initial trajectory up by the tail deflection,and then make the adjustable tail to circumfuse around the forbody's axial according to some given law(cordate curve in this present work),the asymmetrical shape generates roll moment and makes the vehicle slowly go round and round,and finally the vehicle generates spiral maneuvering which has larger maneuvering range in both longitudinal and transversal directions.Because the configuration of the vehicle is optimized,and the condition of "superposition of three centers" is ensured,i.e.the center of gravity of the tail and the center of pressure of the tail is superposed and carefully designed at the same point of the joint hinge simultaneously,the tail is generally within its free-float state which makes the hinge moment equals to or nearly equals to zero.The present work also indicates that lift-rolling movement brings periodic change of angle of attack,angle of sideslip,and the normal overload may achieve as high as 40g,while the peak hinge moment may be as low as 2000 Nm.Furthermore,the variable-bend-tail vehicle can not prosecute high altitude aerodynamic maneuver as its lift-to-drag ratio is not high enough,the solutions are reaction system and configurations of higher lift-to-drag ratio by wing-body and lifting body concept.