Correlation of Analytical Calculations from GRASP (General Rotorcraft Aeromechanical Stability Program) with Torsionally-Soft Rotor Data,

Abstract

As a part of the continuing effort to develop and validate the General Rotorcraft Aeromechanical Stability Program (GRASP), a correlation study is presented to compare the frequency, moment, and stability data for a model-scale, torsionally-soft, helicoptor rotor with GRASP numerical calculations. The hierarchical representation of the model rotor is discussed along with the calculations of the vacuum frequencies, the steady-state blade moments in air, and the aeroelastic stability. Correlation is generally quite good. The GRASP predictions of the first vacuum flap frequencies are outstanding and the first vacuum lag and torsion frequencies correlate reasonably well with the experimental data. Consistently outstanding results are obtained for all of the steady blade moments. The calculations of stability data are in general as good as those made by other programs, but are not quite as good as anticipated.

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Document Details

Document Type
Technical Report
Publication Date
Jan 01, 1987
Accession Number
ADA178881

Entities

People

  • Dewey H. Hodges
  • Donald L. Kunz

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Air Flow
  • Army Aviation
  • Blades
  • Center Of Gravity
  • Coefficients
  • Data Sets
  • Elastic Properties
  • Equations
  • Equations Of Motion
  • Experimental Data
  • Inertia
  • Mass
  • Orientation (Direction)
  • Physical Properties
  • Relative Motion
  • Rotary Wing Aircraft
  • Steady State

Fields of Study

  • Physics

Readers

  • Aerodynamics.
  • Aerodynamics/Aeronautics.
  • Systems Analysis and Design