Stability analysis of the MAAT feeder airship during ascent and descent with wind disturbances
This paper looks into with the aerodynamic properties and stability of the feeder airship in the framework of MAAT project. FP7 MAAT project is based on the concept of two different types of airships (the cruiser and the feeder) working together as a transportation system. The feeder considered in this paper is a rigid airship with an unconventional envelope shape. Aerodynamic forces and moments acting on the airship during the horizontal and vertical flight modes are of special interest in this study, because the aerodynamic performance of the aircraft directly influences its general dynamic behavior and, thus, its in-flight stability. A set of CFD simulations was conducted for vertical and horizontal flights of the feeder airship. Drag and lift forces and pitching moment together with their coefficients, were obtained for different altitudes and velocities from the proposed operational ranges of the airship. Based on the results of CFD simulations the relations between these aerodynamic coefficients and flight parameters were established. For the dynamic modeling purposes, the feeder airship was assumed to be a rigid body. The stability analysis was carried out in frames of the obtained results. The mathematical model of the feeder airship dynamics, was developed using the classic rigid body dynamic approach and the established coefficients relationships. The authors identified the range of the angles of attack for which the airship remains statically stable.