NASA - National Aeronautics and Space Administration

WHEELS UP – The landing gear of NASA Dryden’s Gulfstream G-III aerodynamics research test bed aircraft, tail number 804, retracts after liftoff from Edwards Air Force Base. The aircraft flew a functional check flight on June 26, the first time it's flown in about two years. (NASA / Tony Landis) › View Larger Image

NASA Dryden research pilots Troy Asher and Tim Williams prepare to board the center’s Gulfstream G-III aerodynamics research test bed aircraft, tail number 804, prior to a functional check flight on June 26. (NASA / Tony Landis) › View Larger Image After a hiatus of about two years, NASA Dryden’s Gulfstream III aerodynamics research test bed aircraft, tail number 804, was back in the air for a functional check flight in late June.

The flight June 26 verified that the aircraft has maintained its basic mechanical and electronic functionality following completion of several minor modifications, such as wiring installation and upgrades. Starting in mid-July, a series of research instrumentation checkout flights are scheduled, aimed at verifying the performance of newly installed instrumentation sensors, wiring, infrastructure, and power systems.

These upgrades are in support of its primary Adaptive Compliant Trailing Edge (ACTE) project, a joint effort between NASA and the U.S. Air Force Research Laboratory.

For ACTE, both of the G-III’s conventional 19-foot-long aluminum flaps will be replaced with advanced, shape-changing flaps that form continuous bendable surfaces, improving the aerodynamics of the flaps. Made of composite materials by FlexSys, Inc., the improved flap should eliminate a major source of airframe noise generation.

NASA Dryden’s Gulfstream G-III aerodynamics research test bed aircraft, tail number 804, banks left during a functional check flight June 26. The first time the airplane has been in the air in about two years, the check flight was flown to ensure that its electrical and mechanical systems were operating properly after installation of wiring and other modifications for coming flight test projects. (NASA / Carla Thomas) › View Larger Image When conventional flaps are moved, gaps exist between the forward edge and sides of the flaps and the wing surface. The ACTE flap will be gapless, forming a seamless transition region with the wing while remaining attached at the forward and side. If successful, this experiment will enable aircraft to be significantly quieter during takeoff, approach and landing.

The check flight followed completion of preliminary design reviews on both the ACTE project and on the Discrete Roughness Element (DRE) Laminar Flow Glove Experiment.

The DRE glove is designed to test rows of very small bumps called discrete roughness elements located near the glove’s leading edge. They are designed to maintain natural laminar flow over most of the glove’s surface. Laminar airflow over aircraft wings increases fuel efficiency by helping to reduce aerodynamic drag.

Work with NASA Dryden's G-III Aeronautical Research Test Bed is funded in part by NASA’s Aeronautics Research Mission Directorate as part of the Environmentally Responsible Aviation, or ERA, project under the agency’s Integrated Systems Research Program. Additional funding for aircraft acquisition and the ACTE project is provided by the Air Force Research Laboratory.

Gray Creech, Public Affairs
NASA Dryden Flight Research Center