Documentation of Programs for the Analysis of Performance and Spindle Torque of Controllable Pitch Propellers.

A numerical method for the analysis of controllable pitch propeller characteristics is presented. This inverse problem is complicated due to the unknown circulation distribution and the off-design blade geometry. Therefore, a normal mode collocation method is introduced which simplifies the problem by a combination of design approaches. Starting with the transformation of blade geometry resulting from rotation about the spindle axis, a numerical lifting-surface computation is then applied on the exact three-dimensional basis and solved for the amplitude of each mode by collocation in order to obtain the circulation distribution and the thrust and torque thereof. The work has been modified by a reconstructed vortex lattice distribution and the consideration of hub image and deformed wake effect so that the accuracy is improved.