Aeroelastic Stability for Straight and Swept-Tip Rotor Blades in Hover and Forward Flight

Abstract

Two isolated, hingeless rotors with identical fiber-reinforced composite root flexures were tested in hover and forward flight at realistic tip speeds. The rotors differed in blade planform and structure. The first blade set was of rectangular planform. The second set had blades of stiffer construction with swept-tips. The purpose of these tests was to measure the isolated rotor aeroelastic stability of bending/torsion coupled rotor blades over a range of flight conditions. The two soft inplane rotor systems were designed with low first torsion frequency to emphasize the effects of torsion. Regressing lag mode damping is shown in hover with precone and collective pitch variations and in forward flight with airspeed, shaft angle, precone and collective pitch variations. Correlation with comprehensive analysis for a number of test conditions is shown. Agreement in hover is excellent and forward flight correlation is reasonably good.

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Document Details

Document Type
Technical Report
Publication Date
May 01, 1999
Accession Number
ADA480628

Entities

People

  • Anita I. Abrego
  • David L. Sharpe
  • Thomas H. Maier

Organizations

  • National Aeronautics and Space Administration

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Actuators
  • Army Aviation
  • Center Of Gravity
  • Flight Speeds
  • Frequency
  • Helicopters
  • Hingeless
  • Hydraulic Actuators
  • Instrumentation
  • Leading Edges
  • Mach Number
  • Measurement
  • Momentum
  • Planform
  • Test Stands
  • Wind Tunnel Tests
  • Wind Tunnels

Fields of Study

  • Physics

Readers

  • Aerospace Engineering
  • Structural Dynamics.