A Unified Mathematical Model for High Speed Hybrid (Air and Water-borne) Vehicles.

During the last two decades, the interest in civil and military high speed marine vehicles has lead to several new configurations. Some of them exploit a combination of aerodynamic and hydrodynamic forces to sustain part of the weight of the craft, leading to a hybrid vehicle (HV). This paper focuses on the study of the longitudinal high-speed dynamics of such hybrid vehicles. Since airborne and waterborne vehicles belong to two distinct areas of research, they have been investigated with a rather different approach. The authors propose a unified mathematical model to represent the kinematics suitable for hybrid vehicles, including a detailed analysis of the aerodynamic and hydrodynamic forces acting on the vehicle. Then a set of ordinary differential equations of motion is derived in the frame of small-disturbance stability theory, leading to the Cauchy standard form. An illustrative example of a hybrid vehicle (KUDU II) is analyzed with the proposed method.