Accession Number : AD0860352

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

Descriptive Note : Final rept. Jul 67-Nov 68,

Corporate Author : CORNELL AERONAUTICAL LAB INC BUFFALO NY

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

Report Date : JUL 1969

Pagination or Media Count : 104

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. (Author)

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

Subject Categories : Helicopters
      Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE