Lateral–directional stability is a critical issue for the design of any kind of aircraft. For the hypersonic waverider, the nonaxisymmetric, flat, and slender geometric feature makes it susceptible to the problem of lateral–directional instability. Therefore, the influence of geometric feature on the lateral–directional static and dynamic stability of hypersonic waverider is studied so as to enable the designer to consider this problem in the preliminary aircraft design stage. A series of power-law waveriders is generated at a given design space of the leading-edge parameters. Then, the variation of the static and dynamic derivatives with the design parameter is obtained by use of a surrogate model. It is found that increasing the dihedral angle of the lower surface can improve both the lateral and directional static stability of the total waverider. Furthermore, the dynamic instability mechanisms are analyzed in detail based on the approximate formulas derived from the linearized small-disturbance equations of motion. Especially, a concept of the Dutch-roll dynamic derivative $C_{\mathrm{npDYN}}$ is proposed, which plays an important part in the damping of the Dutch roll. Finally, it is found that increasing the dihedral angle can also improve the damping of the dynamic modes, including the roll, spiral, and Dutch roll.

横向稳定性是任何类型飞机设计的关键问题。对于高超声速乘波器，非轴对称、扁平、细长的几何特征使其容易受到横向不稳定问题的影响。因此，研究了几何特征对高超声速乘波器横向静动态稳定性的影响，以便设计者在飞机初步设计阶段就考虑到这一问题。在前沿参数的给定设计空间中生成一系列幂律乘波器。然后，通过使用代理模型获得静态和动态导数随设计参数的变化。研究发现，增加下表面的二面角可以提高全乘波器的横向和方向静稳定性。此外，基于线性化小扰动运动方程的近似公式，详细分析了动态失稳机制。特别是荷兰滚动态导数的概念$C_{\mathrm{动态}}$建议，它在荷兰卷的阻尼中起着重要作用。最后，发现增加二面角还可以改善动态模式的阻尼，包括滚动、螺旋和荷兰滚动。