Date of Award

Spring 5-1998

Document Type

Thesis - Open Access

Degree Name

Master of Science in Aerospace Engineering

Department

Aerospace Engineering

Committee Chair

Howard V. L. Patrick

Committee Member

Charles N. Eastlake

Committee Member

Yechiel J. Crispin

Abstract

The purpose of this study was to design a quiet 3-Bladed propeller for general aviation aircraft. A combination of design technique and analytical predictions using the NASA Aircraft Noise Prediction Program - Propeller Analysis System (ANOPP-PAS) was used to achieve this goal. The propellers were designed for an engine power of 200 hp, a rotational speed of 2,400 RPM and a free-stream speed of 160 kts. A straight 76 in. diameter 2-bladed propeller was designed as a reference for the 64 in. diameter 3-bladed propeller. The ANOPP-PAS computer code was used for predicting the aerodynamic performance and radiated noise characteristics for both the 2-bladed and 3-bladed propeller designs. Through blade design modifications and the use of conventional, as well as specifically designed natural-laminar-flow (NLF) airfoils, 3-bladed propeller designs resulted in predicted noise reductions of 3.4 dB in the near-field which corresponds to 5.1 dBA; and a 3.4 dB (7.0 dBA) in the far-field when compared to the 2-bladed propeller. These 3-bladed designs resulted in no appreciable change in aerodynamic performance but an estimated 43% weight increase.

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