The paper presents the motion simulation of a Wing in Ground craft with a Lippisch configuration which is stable in terms of static stability. The influence of wind and wave perturbations on the dynamic stability of the flight are investigated.
The analysis of safety and stability used two different approaches. Based on frequency domain simulation, the first approach derived from the classical stability theory utilizes the aerodynamic coefficients and their linearized derivatives. The second approach based on time domain simulation uses the coefficients with full respect to the nonlinear character of aerodynamics in ground effect. The trajectory is used to evaluate the dynamic stability and flight safety of the craft. From the results for typical perturbations, the limitations of the classical stability theory for the flight safety of Wing in Ground craft are shown.
The results show the necessity of the automatic control system even for a satisfying stable craft predicted by the linear theory. The demand of high performance together with the hard constraints for states and control inputs are challenging for the controller design. A proportional-integral-derivative controller is studied to secure the flight safety of small craft under different perturbation and a methodology for designing a control system for operation under various weather conditions is illustrated.