Effects of the airfoil section, the chord and pitch distributions on the aerodynamic performance of the propeller

The main objectives of this study are to investigate parametrically the possible use of alternative airfoils (Joukowski and Göttingen) for propellers and to assess the effects of varying the chord and pitch angle distributions as well as the use of multiple airfoils along the blade on the performance parameters of the propeller. In this study, a validated home-built FORTRAN code based on the BEM method with incorporated tip and compressibility losses is used. The detailed investigation of the blade geometry is done to help in selecting a configuration that is efficient and easy to manufacture. The linear pitch distribution is found to reduce the coefficients of thrust and power as well as higher blade loading at the intermediate region and lower loading at the tip region in comparison with the Göttingen 796-based propeller. The results show that the power coefficient and efficiency of the generalized Joukowski-based propeller are greater than the respective coefficients of Göttingen 796-based propeller for advanced ratio J = 0.85 and higher. The predicted results indicate that the use of the elliptical chord distribution provokes reduction in the blade loading at the tip region and increases at the intermediate region of the blade. It is found also that it reduces the coefficient of thrust, torque and power in comparison with the blade having the reference chord distribution.