An Analytical Study of the Steady Vertical Descent in Autorotation of Single-Rotor Helicopters

Abstract

A detailed% analysis of steadly autorotative vertical aescent of a helicopter is made, in which the effect of considering induced velocity constant over the disk is examined. The induced velocity is first considered constant, then variable over the disk; and the results are compared for a typical helicopter. Although considering the induced velocity constant over the disk causes considerable error in the load distribution along a blade, the revolutions per minute of the rotor and rate of descent are found to be negligibly affected for small angles of blade pitch. For high pitch angles, where blade stalling becomes important, the theoretical difference between blade load distributions obtained by considering induced velocity constant and variable may be expected to be enough to cause quantitative disagreement between the constant Induced-velocity theory and experiment.

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Document Details

Document Type
Technical Report
Publication Date
Jun 01, 1949
Accession Number
ADA380460

Entities

People

  • A. A. Nikolsky
  • Edward Seckel

Organizations

  • Princeton University

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Aerodynamic Characteristics
  • Agreements
  • Angle Of Incidence
  • Autorotation
  • Coefficients
  • Drag
  • Equations
  • Flight
  • Flight Paths
  • Free Stream
  • Helicopters
  • Lepidoptera
  • Load Distribution
  • Physical Properties
  • Power Series
  • Stalling
  • Three Dimensional

Readers

  • Aerospace Engineering
  • Control Systems Engineering.
  • Mathematics or Statistics