Analysis and Initial Optimization of The Propeller Design for Small, Hybrid-Electric Propeller Aircraft

Abstract

This thesis focuses on the optimization of the electric aircraft propeller in order to increase flight performance. Electric aircraft have limited energy, particularly the electric motor torque compared to the fuel engine torque. For that, redesign of the propeller for electric aircraft is important in order to improve the propeller efficiency. The airplane propeller theory for Glauert is selected as a design method and incorporated with Bratt improvements of the theory. Glauert theory is a combination of the axial momentum and blade element theory. Pipistrel Alpha Electro airplane specifications have been chosen as a model for the design method. Utilization of variable pitch propeller and the influence of number of blades has been investigated. The obtained design results show that the variable pitch propellers at cruise speed and altitude 3000 m reducing the power consumption by 0.14 kWh and increase the propeller efficiency by 0.4% compared to the fixed pitch propeller. Variable pitch propeller improvement was pretty good for electric aircraft. The optimum blade number for the design specifications is 3 blades.