Thomas J Andrews

US Patent:

56763352, Oct 14, 1997

Filed:

Mar 8, 1995

Appl. No.:

8/402997

Inventors:

Edward C. Murgia - Chandler AZ
Thomas M. Andrews - Apache Junction AZ

Assignee:

McDonnell Douglas Helicopter Company - Mesa AZ

International Classification:

B64C 2782
B64B 136

US Classification:

244 1719

Abstract:

A system is disclosed for controlling the external flow passing along the external surface of an aircraft such as the tailboom of a helicopter. A fan blows air into a cavity within a surface, and the air exits the surface through one or more axially oriented slots. A ramp structure is positioned within the cavity and upstream of each slot, and a set of fence structures are mounted in each slot and spaced from each other as well as from the ramp structure. The ramp and fence structures trip the airflow which then couples to the downstream side of the ramp and fence structures, thus eliminating the axial airflow component adjacent to the slot, and exits the slot in a direction normal to the axis. The airflow exits the slot in a direction tangential to the external surface and generally parallel with the external flow, resulting in deflection of the external flow and generating lift which is used to augment antitorque control in the helicopter implementation described.