Prediction of Helicopter Rotor Downwash in Hover and Vertical Flight

Abstract

A method is presented for the calculation of rotor downwash in hovering and vertical flight. The blade is represented by a lifting line. The rotor wake is simulated by a vortex sheet and a series of rolled-up root and tip vortices, similar in form to that of a classical fixed-wing. The concept of rectangularization of the rotor wake is used in obtaining a formula for the normal component of induced velocity. Wake contraction based on experimental data is introduced into the calculations. Numerical calculations have been performed for two rotor configurations, viz. S.58, and a model rotor. Computed induced velocities and blade loadings are compared with the available flight data. The comparison shows the present simple method yields satisfactory results.

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Document Details

Document Type
Technical Report
Publication Date
Jan 01, 1979
Accession Number
ADA074154

Entities

People

  • K. R. Reddy

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Aeronautical Engineering
  • Aeronautics
  • Aircrafts
  • Airfoils
  • Applied Mathematics
  • Civil Aviation
  • Engineering
  • Experimental Data
  • Flight
  • Fluid Dynamics
  • Geometry
  • Helicopter Rotors
  • Lepidoptera
  • Mathematical Models
  • Mechanical Engineering
  • Trailing Vortices
  • United States

Fields of Study

  • Physics

Readers

  • Aerodynamics.
  • Aerospace Engineering
  • Fluid Dynamics.