With the advent of variable geometric wing surfaces providing noticeable performance improvements in fixed wing aircraft, a theoretical study of the performance advantages of variable geometry designs for rotary wing aircraft is presented. The analysis is developed in three sections, namely: 1) Theoretical justification of variable geometry through application of simple blade element equations; 2) A simplified design proposal to implement variable geometry in rotor systems; and 3) A numerical comparison of fixed and variable geometry performance statistics applied to specifications of an actual helicopter. / Master of Engineering