Accession Number : AD0860352

Title :   Suppression of Transmitted Harmonic Vertical and Inplane Rotor Loads by Blade Pitch Control

Descriptive Note : Final rept. Jul 1967-Nov 1968

Corporate Author : CORNELL AERONAUTICAL LAB INC BUFFALO NY

Personal Author(s) : Balcerak, John C ; Erickson, Jr , John C

PDF Url : AD0860352

Report Date : Jul 1969

Pagination or Media Count : 101

Abstract : A method was developed to study the possibility of using higher harmonic pitch-angle inputs to eliminate the transmission of oscillatory vertical and inplane forces from a helicopter rotor to its driving shaft. The aerodynamic loads are computed by using a realistic model which represents the rotor blades by bound vorticity distributions and the wake by a mesh of segmented vortex filaments. Computed results are presented for a two-bladed teetering rotor which was approximately the same as that of the UH-1A configuration except for the assumed differences in pitch control. The required pitch-angle inputs were determined for eliminating various combinations of harmonic root shears for three flight conditions.

Descriptors :   *HELICOPTERS, *ROTOR BLADES(ROTARY WINGS), AERODYNAMIC CONFIGURATIONS, CONTROL, DRAG, EQUATIONS OF MOTION, JET HELICOPTER ROTORS, NUMERICAL ANALYSIS, OSCILLATION, VIBRATION, VORTICES

Subject Categories : Helicopters
      Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE