Experimental Investigation of a Variable Collective Pitch Propeller in Near Edgewise Flight

We extend our experiments on fixed and variable collective pitch propellers in forward flight, to near-edgewise flight conditions. Different combinations of blade pitch, incidence angle, and flight speed were tested in an open-jet test section wind tunnel, at incidence angles of 75 to 100 degrees. Higher thrust and power consumption are found at higher incidence angles, which agrees with the previous study and literature. Power required at constant vertical thrust is compared across different incidence angles and advance ratios, to evaluate the efficiency of the variable collective pitch propeller, and to assess whether a rotor-borne vehicle should tilt forward in forward flight or instead remain in purely edgewise configuration and use separate horizontal thrusters for forward propulsion.