| Past analysis of aircraft propellers at Utah State University has resulted in deviation of theory from experiments. It was suspected that inappropriate geometry assumptions were the cause of the deviation. To improve upon the existing Goldstein methodology, the measured geometry of an aircraft propeller was digitized and processed to yield airfoil cross sections at intervals along the blade span. These were analyzed to determine the aerodynamic properties that affect performance, including local αL 0, C˜L(α), and C˜ D(α). The section chord lengths and chord line pitch angles were also measured. The properties were fit to expressions that provided improved geometry assumptions for analysis.; The predictions were compared to new performance data from experiments using the actual propeller that was measured. The results of this comparison show that Goldstein's vortex theory very closely models the physical realities of propeller airflow when appropriate geometry assumptions are modeled into the method. |
