THE STATIC STABILITY OF GROUND EFFECT VEHICLES - THIN JET THEORY

Abstract

A theoretical study of the static pitch stability of simple types of thin jet ground effect machines, including the influence of interior jets, is presented. Some simplifications and assumptions are made but these are kept to a minimum. Tulin's treatment of underfed and overfed jets is used and extended here to take into account the jet flow under the machine. In the expression for the pitching moment, certain nonlinearities are included. The importance of various physical parameters for pitch static stability is calculated and discussed. Two-dimensional machines tend to be unstable at all altitudes except possibly very close to the ground. The use of interior jets stabilizes the machine markedly; stability increasing with decreasing altitude. Increasing the stability generally results in decreased powering efficiency. The general behavior of three-dimensional machines is similar to that of the corresponding two-dimensional machines but with some improvement in stability. Charts are presented to allow the rapid estimation of the static pitch stability of simple machines. (Author)

Document Details

Document Type
Technical Report
Publication Date
Dec 01, 1960
Accession Number
AD0259475

Entities

People

  • William C. Webster

Tags

DTIC Thesaurus Topics

  • Altitude
  • Efficiency
  • Flow
  • Ground Effect
  • Ground Effect Machines
  • Ground Vehicles
  • Jet Flow
  • Surface Effect Vehicles
  • Three Dimensional
  • Two Dimensional
  • Vehicles

Fields of Study

  • Physics

Readers

  • Aerodynamics/Aeronautics.
  • Control Systems Engineering.
  • Fluid Dynamics.