The flight path on launch stage of combined air-breathing hypersonic vehicle(AHV) and booster is maneuverable,and the kinetic mode is affected by the maneuverability of the path which is chosen as the referenced state.The combined aircraft of an AHV and the booster is studied to analyze the modal characteristics of this stage.By using coefficient freezing method,a linearized model is established,and the modal characteristics of the typical freezing point on the maneuverable path are acquired.The mechanism o...