ROTARY WING HOVER PERFORMANCE PREDICTION

THE ACCURATE PREDICTION OF THE PERFORMANCE OF A HELICOPTER ROTOR IN HOVER IS CRITICAL TO THE SUCCESS OF THE DESIGN. A NOVEL APPROACH TO THE SOLUTION OF THE HELICOPTER FREE WAKE HOVER PROBLEM IS ADDRESSED BY FINDING THE SELF-PRESERVING WAKE SHAPE WHICH IS STEADY IN BLADE-FIXED COORDINATES. THE SOLUTION CAN BE USED TO PREDICT THE AVERAGE PERFORMANCE OF ROTOR IN HOVER. THE SOLUTION OBTAINED BY AN INFLUENCE COEFFICIENT METHOD, PROMISES TO BE VERY EFFICIENT AND AVOIDSTHE USE OF A TIME EVOLUTION APPROACH AND THE ASSOCIATED PROBLEMS WITH WAKE INSTABILITY. THE SOLUTION PROCEDURE UTILIZES THE NEW CURVED VORTEX ELEMENT TECHNOLOGY DEVELOPED RECENTLY. THE WORK PROVIDES IMPROVED UNDERSTANDING OF THE FUNDAMENTAL FLUID MECHANICS OF ROTOR WAKES, WHILE OFFERING THE POSSIBILITY OF IMPROVED PREDICTIVE CAPABILITY FOR HOVERING ROTORS.