机翼伸展对低速飞行状态的影响

变翼飞行器在飞行过程中因机翼构型、面积等发生变化,引起质量分布、惯性及气动特性发生相应改变,飞行动力学因此受到影响.基于Lagrange方程,本文首先建立变形机翼飞行器的动力学模型,简化后得到伸展变翼的纵向运动方程,并通过气动仿真获得伸展机翼飞行器的低速气动特性.然后,借助线性插值确定气动参数随翼展的变化关系,研究了伸展变翼过程对于飞行器平飞、爬升、俯冲和盘旋的作用.结果表明,因变翼过程中升阻系数改变,飞行器将发生变速沉浮运动,此时为保持飞行状态的稳定,需对飞行器加以控制.

The effect of wingspan change on low speed flight of a morphing aircraft

The flight dynamics of a morphing aircraft is obviously depended on the wing shape, because it results in different aerodynamic properties due to the mass reallocation and inertia change. This paper studies the flight dynamics of a changeable wingspan aircraft in low speed flight. Starting with the modeling of the morphing aircraft on the basis of Lagrange's equation, a set of longitudinal dynamic equations for a planar deployable wing is established. At the same time, the low speed aerodynamic parameters for fixed wingspan are calculated with the vortex lattice method. Afterward, the corresponding aerodynamic coefficients versus the wingspan changes are determined through the use of linear interpolation method. The effect of wingspan changes on the flight dynamics of the simplified morphing aircraft are analyzed for different flight status such as level flight, climbing, diving and turning. The results show that wingspan change would influence the flight status of morphing aircraft especially in the longitudinal flight so that the relevant control must be taken in order to keep the stability of the flight of a morphing aircraft.