I'm doing an experiment to see if adding small "winglets" (that I've called "tiplets") to a propeller blade will reduce the drag the way winglets work on an airplane wing. The propeller blade is a lofted base formed like an extrusion of a basic airfoil shape. I imported the airfoil coordinates and created a spline using those coordinates. I lofted the blade between three of these airfoil splines, each on their own plane so I can adjust the angle of each one.
The "tiplet" needs extend outward from the blade tip slightly, curve upwards/back towards a point that defines the height. I've added points on both the tip plane and tiplet plane thinking these would help define the shape of the tiplet loft. If I select the airfoil curve as the profile for the loft, and the tiplet end point on the tiplet plane, it works, but creates a triangular tiplet. I'd like the tiplet to be rounded. I tried adding guide curves as a spline on both the tip plane and the tiplet plane, no luck. I've tried adding a 3D plane using three points, the leading edge of the blade on the tip plane, the trailing edge of the blade on the tip plane, and the top tiplet point on the tiplet plane. I drew a spline on that plane to use as guidelines..again, no luck.