The effect of ballonet slosh on an airship's longitudinal motion

Abstract

An airship has usually two or three ballonets in its envelope in which air is contained. Its buoyancy and attitude control is performed by changing the air content of each ballonet. It is said that ballonet slosh may influence an airship's stability or ride quality. However, no quantitative treatment has been performed so far to investigate this phenomenon. In this paper the coupled equations of an airship longitudinal motion are formulated by modeling the ballonets as cylindrical containers. Some numerical calculations are performed for a 25 m class airship and it has been shown that the ballonet slosh may become a design issue when the shape of the ballonet is thinner or when the ballonet size becomes larger. © 2004 The Japan Society for Aeronautical and Space Sciences.