Experimental Investigation of Transition of a Model Helicopter Rotor From Hovering to Vertical Autorotation

Abstract

An experimental investigation has been carried out to study the variation of average induced flow around a model helicopter during transition from a hovering condition to steady autorotative vertical descent. Test data were obtained from simulated power failures under many different conditions. Results are summarized for variations in disk loading, blade angles, and rate of pitch change. Calculations were made of effective induced velocity for the various conditions. Sample comparisons of calculated and experimental performance were made. The results of these tests show that the manner in which effective induced velocity varies during the transition to autorotation often differs greatly from the exponential variation assumed in the theoretical analysis (NACA TN 1907). It is also shown that conditions peculiar to vertical descent in the transition range cause variations in performance of the model not predicted by this method.

Open PDF

Document Details

Document Type
Technical Report
Publication Date
Mar 01, 1952
Accession Number
ADA380404

Entities

People

  • Robert R. Lynn
  • Robin B. Gray
  • S. E. Slaymaker

Organizations

  • Princeton University

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Accuracy
  • Actuators
  • Autorotation
  • Coefficients
  • Displacement
  • Drive Shafts
  • Drop Tests
  • Electric Contacts
  • Electrical Equipment
  • Experimental Data
  • Helicopter Rotors
  • Hot Wire Anemometers
  • Hydraulic Actuators
  • Measurement
  • Release Mechanisms
  • Reynolds Number
  • Steady State

Fields of Study

  • Physics

Readers

  • Aerospace Engineering
  • Fluid Dynamics.
  • Mathematics or Statistics