A body, a cavity located on the body, enabling to place ammunition and similar payloads therein, a rear wall which is the surface on which an airflow occurring with the movement of the body leaves the cavity, and a floor over which the airflow moves along the cavity is disclosed.

An aircraft landing gear 100 includes a structural main leg 110, having a substantially circular cross-section and defining a front side for facing upstream in use and a rear side for facing downstream in use. The landing gear includes a shaped element 151 attached to an attachment point located on the rear side of the structural main leg. The shaped element extends rearwards from the structural main leg to provide a combined cross-sectional shape of the structural main leg and shaped element that is elongated in the upstream-downstream direction compared to the structural main leg.

A cavity system (300-600) is provided. The cavity system comprises a cavity (2) and a spoiler (304-604). The spoiler (304-604) comprises at least one plate (4) having a front surface and a rear surface, and an undulating edge. The spoiler (304-604) is positioned in the proximity of a leading edge (14) of the cavity (2), the leading edge (14) being relative to an actual or intended flow direction (3) of a fluid over the cavity (2), and the spoiler (304-604) is arranged with its longitudinal axis (1) perpendicular to or at an oblique angle to the actual or intended flow direction (3) such that the front surface faces towards the flow direction (3).