Won In

Date of Award


Document Type


Degree Name

Master of Science


Department of Aeronautics and Astronautics

First Advisor

Milton E. Franke, PhD


As future aircraft migrate toward tailless, blended wing body configurations, aircraft designers are faced with a lack of experimental data that represent these types of configurations. A wind tunnel investigation was conducted to identify the ground effect region of two unmanned combat air vehicle (UCAV) models. The AFIT low-speed wind tunnel (LSWT) and ground plane were used to study the forces and moments on the UCAV models in ground effect. The Chevron and Lambda planforms used in this study were originally tested in full-scale for stability and control without ground effects. A static ground plane was used in this study. Hot-wire results showed a minimal difference between the transducer velocity and the hot-wire measured velocity and these differences were accounted for as wind tunnel blockage. In addition to hot-wire results, flow visualization results revealed the AFIT LSWT had an adequate testing environment for the use of the ground plane. The ground effect region for the Chevron and Lambda UCAVs was characterized by an increase in lift, drag, and a decrease in lift-to-drag ratio. These trends were also noted in previous studies of similar aspect ratio and wing sweep.

AFIT Designator


DTIC Accession Number