Flight Test Evaluation of a Nonlinear Hub Spring on a UH-1H Helicopter.

Abstract

A nonlinear hub spring design and results of the subsequent flight testing as a concept to provide increased mast bumping safety margin for the UH-1H helicopter is presented. Although there is a need for additional testing, the hub spring is shown to provide an increased margin of safety by reducing main rotor flapping in all conditions tested. As a part of this effort, a hybrid computer program was verified as able to predict mast loads due to flapping stop contact. Using this program a parametric study of mast loads as a function of rotor flapping was performed in order to develop a design criteria to ensure that mast loads can be sustained during in-flight flapping stop contact. In addition, a comparison of the main rotor flapping predicted by the hybrid computer and the digital computer C81 program using elastic blades is shown, Also, an evaluation of U. S. Army helicopter tactics to determine which NOE maneuvers are susceptible to high main rotor flapping is presented. (Author)

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Document Details

Document Type
Technical Report
Publication Date
Apr 01, 1981
Accession Number
ADA098794

Entities

People

  • J. D. Honaker
  • J. R. Van Gaasbeek
  • Joshua M. Carr
  • L. W. Dooley
  • P. J. Hollifield

Organizations

  • Bell Flight

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Aircraft Equipment
  • Aircrafts
  • Airframes
  • Computer Programs
  • Computer Simulations
  • Design Criteria
  • Failure Mode And Effect Analysis
  • Fuselages
  • Helicopters
  • Hybrid Computers
  • Landing Gear
  • Margin Of Safety
  • Mathematical Models
  • Plastic Explosives
  • Resonant Frequency
  • Spars
  • Springs

Fields of Study

  • Physics

Readers

  • Aerodynamics.
  • Aviation Science / Aeronautics.
  • Robotics and Automation.