Development of a Free-To-Roll Transonic Test Capability

Abstract

As part of the NASA/Navy Abrupt Wing Stall Program, a relatively low-cost, rapid-access wind-tunnel free-to-roll rig was developed. This rig combines the use of conventional models and test apparatuses to evaluate both transonic performance and wing-drop/rock tendencies in a single tunnel entry. A description of the test hardware as well as a description of the experimental procedures is given. The free-to-roll test rig has been used successfully to assess the static and dynamic characteristics of three different configurations--two configurations that exhibit uncommanded lateral motions, (pre-production F/A-18E and AV-8B), and one that did not (F/A-18C). SYMBOLS AND ABBREVIATIONS AWS abrupt wing stall C A axial force coefficient C ι rolling moment coefficient C N normal force coefficient C m pitching moment coefficient C n yawing moment coefficient C Y side force coefficient FTR free to roll