Interactional Aerodynamics of the Single-Rotor Helicopter Configuration. Volume I.

摘要

A study has been conducted to understand the interactional aerodynamics problems occurring during the UTTAS development. Powered wind tunnel model data were organized and analyzed in the following categories of interactions: Rotor/ground; Rotor/fuselage; Rotor/fuselage/ground; Rotor/empennage; and Rotor/empennage/ground. The following related problem areas are considered: Severe lateral trim changes during transition close to the ground; The occurrence of high vibratory aerodynamic loads on the airframe surfaces; Turbulent flow on the airframe near the ground; Excessive low-frequency unsteady loads on the empennage in forward flight due to the hub/rotor wake; and Poor efficiency in tail rotor installations due to adverse fin loading.