TWO-DIMENSIONAL TESTS OF AIRFOILS OSCILLATING NEAR STALL. VOLUME 1. SUMMARY AND EVALUATION OF RESULTS

Abstract

An experimental investigation into rotor blade dynamic stall was conducted. Two typical airfoils, the NACA 0012 (modified) and the Vertol 23010- 1.58, were tested by measuring the differential pressures acting during pitching and translatory oscillations over a range of angles of attack covering the stall regime. There were two main objectives. The first was to determine the influence of stall on the aerodynamic pitching moment of an airfoil executing pitching motions corresponding to the elastic torsional oscillations of a rotor blade. The second was to determine the extent to which time-varying angle of attack could affect the maximum aerodynamic lift that a rotor blade can develop. The cambered profile remained free of negative damping for 3 to 6 degrees beyond the point where the symmetrical section encountered negative damping in the Mach 0.2 to 0.4 range. The cambered section exhibited higher attainable C sub N's than the symmetrical section under all conditions of motion, except for the highest frequency tested at Mach 0.6.

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Document Details

Document Type
Technical Report
Publication Date
Apr 01, 1968
Accession Number
AD0670957

Entities

People

  • Franklyn J. Davenport
  • Ivor C. Walton
  • Jaan Liiva
  • Lewis Gray

Organizations

  • Boeing Rotorcraft Systems

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Aerodynamic Configurations
  • Aerodynamic Forces
  • Aircrafts
  • Airframes
  • Boundary Layer
  • Computer Programs
  • Flow Visualization
  • Fluid Dynamics
  • Frequency
  • Helicopter Rotors
  • Pressure Distribution
  • Recording Systems
  • Resonant Frequency
  • Test And Evaluation
  • Test Facilities
  • Two Dimensional
  • Wind Tunnels

Fields of Study

  • Physics

Readers

  • Aerodynamics/Aeronautics.
  • Aerospace Engineering
  • Structural Dynamics.