Professionally converted for accurate flowing-text e-book format reproduction, this NASA documents the contributions of Langley Research Center to specific military aircraft that were operational in the 1990's. Virtually all military aircraft that participated in Operation Desert Storm, Kosovo, and other peacekeeping missions of this era have Langley technical contributions to their design, development, and support. In some instances Langley research from one aircraft development program helped to solve a problem in another development program. At the conclusion of some development programs, Langley researchers obtained the research models to conduct additional tests to learn more about previously unknown phenomena. These data also proved useful in later developmental programs. Perhaps the most consistent element in all of the research programs is the length of time for the development and maturation of new research concepts before they are implemented in new aircraft. Many of the military aircraft in the U.S. inventory as of late 1999 were over 20 years old. Langley activities that contributed to the development of some of these aircraft began over 50 years prior. This publication documents the role—from early concept stages to problem solving for fleet aircraft—that Langley played in the military aircraft fleet of the United States for the 1990's. The declassification of documents and other material has provided an opportunity to record the contributions of Langley personnel and facilities and discuss the impact of these contributions on Department of Defense aircraft programs. BAI Exdrone BQM-147A * Highlights of Research by Langley for the Exdrone * Langley Contributions to the Exdrone BQM-147A * Background * Langley Research Efforts * Subsequent Exdrone Vehicle Applications * Boeing AV-8 Harrier * Highlights of Research by Langley for the AV-8 * Langley Contributions to the AV-8 * Background * Contributions to the P.1127 * Contributions to the Kestrel * Contributions to the AV-8 * Boeing C-17 Globemaster III * Highlights of Research by Langley for the C-17 * Langley Contributions to the C-17 * The CX Competition * The Externally Blown Flap Concept * TheYC-15 * The C-17 Supercritical Wing, Winglets, and Aerodynamic Studies * Composite Materials * Fly-by-Wire Control System * Avoiding the Deep Stall * Recognition Visit * Boeing F/A-18 Hornet * Highlights of Research by Langley for the F/A-18 * Langley Contributions to the F/A-18 * Vortex Lift and Maneuvering Flaps * Development of the YF-17 * F/A-18A to F/A-18D * Development of the F/A-18 * Cruise Drag * High-Angle-Of-Attack, Spin, and Spin Recovery Characteristics * The NASA High-Angle-Of-Attack Technology Program * The Falling-Leaf Maneuver * Flutter Clearance and Tail Buffet * Thrust-Vectoring Research * F/A-18E/F * The Super Hornet * Cruise Performance * Redesign of the Leading-Edge Extension * High-Angle-Of-Attack Characteristics * Spin Tunnel and Drop-Model Tests * Flutter Tests * Wing Drop * Boeing T-45 Goshawk * Highlights of Research by Langley for the T-45 * Langley Contributions to the T-45 * Early Configuration Development * Stall Characteristics * Spin Characteristics * Ground Handling * Inlet Performance * Fairchild Republic A-10 Thunderbolt II * Highlights of Research by Langley for the A-10 * Langley Contributions to the A-10 * The A-X Competition Spin Recovery * General Dynamics F-111 Aardvark * Highlights of Research by Langley for the F-111 * Langley Contributions to the F-111 * The Variable-Sweep Wing Concept * The Tactical Fighter Experimental (TFX) Program * Aerodynamic Performance * Propulsion Integration * High-Angle-of-Attack Characteristics * Spin Recovery * Flutter Tests * Crew Escape Module. * Wing Box Problem