Accession Number:

AD0775929

Title:

Aerodynamic Damping of Vibrating Helicopter Rotors.

Descriptive Note:

Final rept. 11 Jun 70-21 Dec 73,

Corporate Author:

SOUTHWEST RESEARCH INST SAN ANTONIO TEX

Report Date:

1974-01-01

Pagination or Media Count:

63.0

Abstract:

An experimental and theoretical study of aerodynamic damping of a hingeless helicopter rotor harmonically excited in heave in one of several bending modes is presented. Experimental damping data is given for rotor pitch angles of 0, 1 and 5 degrees. At each pitch angle, damping data is presented for a wide range of the oscillation to rotational frequency ratio, m. Rotor structural damping as a function of rpm is also determined so an accurate measure of aerodynamic contributions to total rotor damping is obtained. Theoretical aerodynamic damping is determined by treating the model rotor as a multi-degree of freedom system wherein the structural and aerodynamic properties of the rotor are treated as a series of finite structural elements and a series of two-dimensional strip theory aerodynamic panels. Modified author abstract

Subject Categories:

  • Aerodynamics
  • Helicopters

Distribution Statement:

APPROVED FOR PUBLIC RELEASE