Propeller optimization strive to performance acoustic tradeoff

Ohad Gur (Israel Aerospace Industries)

This paper describes the design of a propeller-based electric-propulsion system for hover condition. The design procedure harnesses modeFRONTIER optimization framework with various single- and multi-objective hybrid optimization schemes. Several analyses were integrated to the design framework and propeller geometry optimizations were conducted. The multi-objective problem consisted of trade-off between the contradicting goals of performance (required electric power at hover) and acoustics (tonal overall sound-pressure-level). Using various hybrid optimization schemes, the Pareto tradeoff fronts were found for 2, 3, and 4 bladed propellers. These propellers are compared to an off-the-shelf propeller blade (Mejzlik 18x6) which is used as a reference. This reference propeller proves to be good design, compared to the optimized results. Still, from the optimized Pareto results, 4 propeller configurations were chosen to be fabricated and tested. These configurations are optimized by their acoustic or performance trade-off. These optimized propellers represent a good compromise, which is better than the reference propeller.