Accession Number:

ADA209152

Title:

Glider Ground Effect Investigation

Descriptive Note:

Master's thesis

Corporate Author:

AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING

Personal Author(s):

Report Date:

1989-05-01

Pagination or Media Count:

132.0

Abstract:

This research used glider flight tests and optimized glider simulations to evaluate the aerodynamics of ground effect and to determine the optimum flight profile for maximum gliding range in gliders. A series of 122 sorties were flown in the Grob G-103 Twin II and the Let L-13 Blanik gliders on a specially designed very low altitude speed course. Radar tracking data were used to determine the glider position and velocity, and a 3 degree of freedom glider performance simulation was used to determine the glider parasite and induced drag coefficients in ground effect. Lifting line derived predictions of ground effect induced drag reduction developed by Dr. Sighard Hoerner were found to be accurate at altitudes above 20 percent wingspan but were up to 16 percent too optimistic at low altitudes. A revised prediction of ground effect induced drag reduction was developed based on the flight test data, and this revised prediction was used along with a turbulent boundary layer wind model in two optimization algorithms to develop the optimum flight profiles for maximum range gliding flight.

Subject Categories:

  • Aerodynamics
  • Gliders and Parachutes
  • Fluid Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE