METHOD OF ESTIMATING HORIZONTAL COMPONENTS OF INDUCTIVE VELOCITIES AT SINGLE-ROTOR HELICOPTER LOW FLIGHT SPEEDS

摘要

FIELD: transport.SUBSTANCE: invention relates to aircraft engineering, particularly, to aerodynamics of single-rotor helicopter rotor. Proposed method comprises preliminary flight tests with visualisation of end vortices by smoke provided by smoke generator at flight speeds lower than 0.2 km/h. Note here that video cameras is used to register airflow ram effects at rotor on the side of approach flow at the distance from rotor rotation axis to intersection of end vortices with blade cone in azimuth of 180 degrees. Rotor angle of attack is defined as well as relative speeds of end vortices sweep form rotor blades for preset helicopter speed. Velocity of approach airflow is defined by standard instruments as well as local air speed nearby rotor by air pressure receiver arranged at rotor blade to define the structure and geometry of rotor vortex trace visualised by end vortex smokes and to determine circulation of lengthwise vortices. Then, horizontal components of horizontal inductive speeds nearby helicopter from rotor vortex trace at positive angles of attack at preset points are calculated.EFFECT: higher validity of determination.2 cl, 4 dwg