Accurate prediction of the flutter velocity boundary of a supersonic vehicle is one of the key and difficult points in the aeroelasticity research of a supersonic vehicle. Aiming at the problems of a high degree of freedom and complex flutter mode coupling form of the supersonic vehicle model, a structural reduce-order modeling method based on the unmatched substructure method is proposed, and aeroelastic flutter modeling is realized by combining unsteady piston theory and fluid-solid coupling interpolation theory. The conventional mode method, the traditional substructure method, and the unmatched substructure method are used to investigate the supersonic flutter characteristics of a panel model and a swept wing model. The results show that, compared with commercial software, the relative error of the main low-order frequency and flutter velocity of the model is less than 1.1% and 1.3% respectively. Compared with the traditional modal method, the substructure method requires fewer modal orders. As a result, the suggested approach can effectively and precisely forecast the flutter characteristics of common supersonic aircraft.

To overcome the drawbacks such as large wing deformations, poor performance encountering gusts, limits in taking off and landing, inconvenience of transportation of High-Altitude Long-Endurance (HALE) Unmanned Aerial Vehicles (UAVs), a new conceptual aircraft called wingtip-docked Multi-Body Aircraft (MBA) has attracted lots of attentions. Aiming to investigate the feasibility of this concept, two UAV models were designed, manufactured and connected by a wingtip-docking mechanism, which only allows the relative roll motion between the two aircraft. The trim solution of the two connected aircraft is firstly obtained by solving the developed nonlinear flight dynamic equations, followed by the stability analysis based on the linearized model. The results show that the connected aircraft is inherently unstable and cannot fly without a reasonable flight control system. A set of Proportional-Integral-Derivative (PID) control laws was then developed and implemented in the two experimental aircraft. The success of the flight tests show that the flight control can effectively eliminate the unstable motion and the wingtip-docked MBA is controllable and feasible.