Aeroservoelastic Investigations of a High-Aspect-Ratio Motor Glider
This paper presents aeroservoelastic investigations for the STEMME S15 prototype using a methodology of modelling the flexible aircraft dynamics in the time domain. The effects of the flexibility in the closed-loop stability according to the sensor positioning are discussed, for a pitch and a yaw damper. The modelling of the flexible dynamics is based on the mean axes approximation, without considering the inertial coupling between the rigid-body and the elastic degrees of freedom. The structural dynamics is linearly represented in modal coordinates. To determine the incremental aerodynamics due to elastic deformations, an unsteady strip theory formulation in the time domain is used, considering the exponential representation of the Wagner function and the resulting stripwise aerodynamic lag states. Spanwise correction to account for three-dimensional effects at the wing tip based on the quasi-steady circulation distribution was applied. The validation of the open-loop flexible aircraft simulations with flight test results are also presented.