Investigation of Reynolds Number Effects on a Generic Fighter Configuration in the National Transonic Facility

A wind tunnel test of a generic fighter configuration was tested in the National Transonic Facility through a cooperative agreement between NASA Langley Research Center and McDonnell Douglas. The primary purpose of the test was to assess Reynolds number scale effects on a thin-wing, fighter-type configuration up to full-scale flight conditions (that is, Reynolds numbers of the order of 60 million). The test included longitudinal and lateral/directional studies at subsonic and transonic conditions across a range of Reynolds numbers from that available in conventional wind tunnels to flight conditions. Results are presented for three Mach numbers (0.6, 0.8, and 0.9) and three configurations: 1) Fuselage / Wing, 2) Fuselage / Wing / Centerline Vertical Tail / Horizontal Tail, and 3) Fuselage / Wing / Trailing-Edge Extension / Twin Vertical Tails. Reynolds number effects on the longitudinal aerodynamic characteristics are presented herein. 1Aerospace Engineer, Research Facilities Branch, Member, AIAA 2Aerospace Engineer, Configuration Aerodynamics Branch, Associate Fellow, AIAA 3Assistant Branch Head, Configuration Aerodynamic Branch, Associate Fellow, AIAA 4Aerospace Engineer, Configuration Aerodynamics Branch, Associate Fellow, AIAA SAerospace Engineer, Flow Physics and Control Branch, Senior Member,AIAA Copyright © 2002 by the AmericanInstitute of Aeronautics and Astronautics, Inc. No copyright is asserted in the United States under Title 17, U. S. Code. The U. S. Government has a royalty4ree license to exercise all rights under the copyright claimed herein for Governmental Purposes. All other rights are reserved by the copyright owner. INTRODUCTION Simulation of flight at full-scale Reynolds numbers is now available through the use of cryogenic wind tunnels, such as the National Transonic Facility (NTF) at the NASA Langley Research Center. Some of the initial models tested in this facility were those built to study the Reynolds number effects on transport aircraft. These models were composed of U.S. aircraft industry designed and fabricated wings mounted to a NASA supplied generic fuselage, denoted as Pathfinder I (refs. 1 and 2). A similar need was identified for studying fighter aircraft concepts using a generic, area-ruled fuselage, which could accommodate a variety of wing planforms. NASA has denoted the fuselage for the configuration as Pathfinder I1. Further general discussion of the Pathfinder II family of models can be found in references 1 3. The objectives of this wind tunnel investigation, utilizing the Pathfinder II fuselage with a McDonnell Douglas defined thin, fightertype wing, were to study the effects of Reynolds number on a fighter-type configuration through model component build-up and with stability and control device deployment (ref. 4). The test was conducted to provide a database of Reynolds number effects, up to full scale, which could be used to determine Reynolds number correlation trends, provide data for assessment of computational fluid dynamics (CFD) methods including turbulence modeling, and validate design and analysis methods. This paper presents results from a single wind tunnel test, conducted from November December 1995, focused on the Reynolds number sensitivities of longitudinal aerodynamic characteristics at subsonic and transonic conditions for three distinct configurations. The three major configurations 1 American Institute of Aeronautics and Astronautics