AIRFOIL CONSIDERATIONS IN THE DESIGN OF HIGH PERFORMANCE, LOW REYNOLDS NUMBER PROPELLERS

A propeller was designed using 2D airfoil data obtained from a panel method numeric code. The propeller was designed to operate at 75% chord based Reynolds number of 20k. At low Reynolds numbers <40k, there are no publicly available 2D airfoil force data largely because of inherent difficulty in their measurement. Theoretical prediction of the propeller's peak efficiency was 0.67 while experiment results was 0.58. To improve the propeller efficiency by using better performing airfoils, six (6) airfoils of varying thickness and camber were studied. Three of the six airfoils were chosen and used in the design of three propellers - a single airfoil for each propeller design. The propellers were designed to operate at Reynolds number of 30k at 0.75 radius and the 2D airfoil force data used for the designs were obtained from a numeric code. Theoretical predictions of efficiency were all > 81% in each of the designed propellers.