PREDICTION OF TAIL ROTOR THRUST AND YAW CONTROL EFFECTIVENESS

A comprehensive tail rotor model capable of predicting the tail rotor thrust under a combination of axial and edgewise flow is developed. Th e predicted tail rotor thrust is correlated in hover and in low speed flight at different azimuth angles, An empirical tail rotor/vertical f in interaction model is developed from wind tunnel data, Predictions o f the SH-2 trim pedal position with the isolated tail rotor alone as w ell as including the main rotor wake and tail rotor/fin interactions a re obtained and correlated with flight test data, The isolated main ro tor wake induces considerable velocities at the tail rotor location an d, when included in the analysis, has a significant effect on the pred ictions of pedal position, The tail rotor/fin interactions affect the predictions of pedal position considerably in right sideward flight, p articularly at speeds above 25 knots.