A Mathematical Model to Analyze the Static Stability of Hybrid (Aero-Hydrodynamically Supported) Vehicles.

Among the new concepts developed for high speed marine vehicles over the lasttwo decades, the "aerodynamic alleviation" approach consists inusing an aerodynamic surface to "alleviate" the weight sustained bythe hydrodynamic lift. Such vehicle experiences aerodynamic and hydrodynamicforces of the same order of magnitude, therefore the dynamic models developedfor airborne and waterborne vehicles are not suitable. Considering a vehiclehaving a high-speed prismatic planing hull and one or more aerodynamic surfaces,the authors propose two mathematical methods. The first one calculates theequilibrium attitude of the vehicle at a given speed and its numericalimplementation has been used to undertake a parametric analysis of the influenceof some configuration characteristics on performances. The second methodanalyzes the static stability of the HV. Starting from the dynamic analysispreviously proposed by the authors, the characteristic polynomial of the HVdynamics is derived and a static stability criterion is proposed.