ROTOR SYSTEM HAVING ALTERNATING LENGTH ROTOR BLADES FOR REDUCING BLADE-VORTEX INTERACTION (BVI) NOISE

摘要

A rotor system (4) having odd and even blade assemblies (Ob, Eb) mounting to and rotating with a rotor hub assembly (6) wherein the odd blade assemblies (Ob) define a radial length RO, and the even blade assemblies (Eb) define a radial length RE and wherein the radial length RE is between about 70 % to about 95 % of the radial length RO. Other embodiments of the invention are directed to a Variable Diameter Rotor system (4) which may be configured for operating in various operating modes for optimizing aerodynamic and acoustic performance. The Variable Diameter Rotor system (4) includes odd and even blade assemblies (Ob, Eb) having inboard and outboard blade sections (10, 12) wherein the outboard blade sections (12) telescopically mount to the inboard blade sections (10). A positioning means (70) is provided for positioning the outboard blade sections (12) with respect to the inboard blade sections (10) such that the radial length RE of the even blade assemblies (Eb) is equal to the radial length RO of the add blade assemblies (Ob) in a first operating mode, and such that the radial length RE is between about 70 % to about 95 % of the length RO in a second operating mode.