An Analysis of the Transition of a Helicopter From Hovering to Steady Autorotative Vertical Descent

Abstract

An analytical study is presented of the transition from hovering flight (power on) to steady vertical descent (in autorotation) following power failure while hovering. The effects of hinging the blades, of blade moment of inertia, and of rapidity of pitch reduction after power failure are investigated. The results indicate that the effect of blade flapping is negligible as far as the establishing of steady autorotation is concerned. From the standpoint of avoiding excessive blade stalling during the transition, it is desirable that the blade pitch be reduced as rapidly as possible after power failure, and that the blade moment of inertia be large. Sample calculations and graphs of computed transitions for a typical helicopter are presented.

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Document Details

Document Type
Technical Report
Publication Date
Jun 01, 1949
Accession Number
ADA380538

Entities

People

  • A. A. Nikolsky
  • Edward Seckel

Organizations

  • National Aeronautics and Space Administration

Tags

Communities of Interest

  • Air Platforms
  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Aerodynamic Characteristics
  • Altitude
  • Angle Of Incidence
  • Angular Acceleration
  • Autorotation
  • Coefficients
  • Differential Equations
  • Equations
  • Equations Of Motion
  • Flight
  • Helicopters
  • Hovering
  • Inertia
  • Intervals
  • Maneuvers
  • Moment Of Inertia
  • Steady State

Fields of Study

  • Physics

Readers

  • Aerospace Engineering
  • Control Systems Engineering.