A Detailed Numerical Evaluation Of Shroud Performance For Finite Bladed Ducted Propellers

Based on the three-dimensional theory developed at Therm Advanced Research, a simple procedure for calculating the detailed aerodynamic loading on the shroud of a finite-bladed ducted propeller in forward flight is presented. This procedure was designed for the evaluation of the several thousand configurations exactly represented by the tabulated values of the pertinent parameters, or reasonably approximated by them. In addition, configurations whose parameters fall somewhat in between or outside these values can be evaluated by suitable interpolation or extrapolation. The data were selected through liaison with propeller and aircraft manufacturers to encompass the current state of the art for ducted propeller design. As a result, it is possible to carry out a number of calculations by hand quite readily which could not be done heretofore, for example, the examination of the effect of the propeller advance ratio.