| 摘要 |
The present application proposes a device and method for controlling the size of a sheet of ice which can build up on an aircraft surface as a result of icing, particularly SLD icing. In some circumstances it is possible to tolerate a build up of some ice without significant aerodynamic penalties. However, the size of such ice sheets must be controlled to ensure that any ice sheet detaching from the aircraft surface has a mass that is within the acceptable margins for projectiles which may impact aircraft structure downstream. Thus, a first aspect of the invention provides an aircraft having an exterior surface (200) arranged to face upstream in the airflow direction during flight and a plurality of anti-ice accretion projections (500) extending away from the exterior surface. Each anti-ice accretion projection has a leading edge (510) facing upstream in the airflow direction and a trailing edge (520) facing downstream of the airflow direction, wherein the trailing edge provides an aerodynamic step (540) extending substantially perpendicular to the airflow over the exterior surface. The step is arranged to: create a shadow region immediately downstream of the projection where water droplets carried in the airflow cannot impinge on the exterior surface; and/ or create a region of separated flow over the exterior surface immediately downstream of the projection. |
