Date of Award

12-2017

Document Type

Thesis - Open Access

Degree Name

Master of Science in Aerospace Engineering

Department

Graduate Studies

Committee Chair

Dr. J. Gordon Leishman

First Committee Member

Dr. Tasos Lyrintzis

Second Committee Member

Dr. John Ekaterinaris

Abstract

The purpose of this study was to investigate the effect of rotor morphing, specifically variable rotor speed and variable blade twist, on various parameters such as the distribution of angle of attack, lift, power, thrust and/or other metrics describing the performance of a helicopter rotor. A MATLAB based blade element theory model was developed and executed for different flight conditions. The model was validated against the flight test data of a UH-60. Effects on power, lift to drag ratio and rotor drag from variations in blade twist, rotor speed, rotor radius and blade chord was analyzed. Morphing cases were applied as linear functions of airspeed. Linearly varying rotor speed provides the most benefits at higher airspeeds for individual morphing cases, while linearly varying twist with airspeed provided the most rotor drag reduction. For cases where two elements of morphing were used, varying blade twist and radius provided the most benefits at higher airspeeds, while also providing the most drag reductions in all cases. When morphing twist, radius and rotor speed simultaneously, the power reductions obtained were the most significant, while also having substantial decreases in rotor drag. A maximum power reduction of about 20% was obtained at higher airspeeds with the judicious application of all elements of blade and rotor morphing.

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