PERFORMANCE AND STRESSES OBTAINED ON AN ISOLATED VTOL-TYPE PROPELLER OPERATING IN HOVERING, TRANSITIONAL, AND AXIAL FLIGHT

Abstract : Experimental performance and blade stresses measured on a three- bladed VTOL-type propeller tested in free air are presented. The isolated propeller was tested over ranges of prop speed, forward velocity, blade angle setting, and thrust axis to free-stream angle. Correlation with a theoretical method of predicting propeller performance and blade stresses was made. It was found that when the propeller was operating in a flight condition for which the theory was developed, correlation between theory and experiment was good. When the propeller was operating in a flight condition where very small positive or negative effective angles of attack were encountered, correlation between theory and experiment was poor. (Author)