The 8×6 is a world-class facility that provides researchers with the opportunity to explore higher speed regions of flight. It is NASA’s only transonic propulsion wind tunnel. Actively involved in research testing for over 65 years, this facility has been used to enhance the nation’s aeronautics program serving industry, academia, and NASA in-house efforts. Aircraft such as the Advanced Turboprop, the National Aerospace Plane, and Advanced Tactical Fighter, the Joint Strike Fighter, and the High-Speed Civil Transport have been tested in this facility.
The test section of this facility is 8 feet high by 6 feet wide and 23.5 feet long. The flexible wall nozzle located upstream of the test section is constructed entirely of stainless steel and is used to accelerate the free-stream airflow when its walls are contoured to form a convergent divergent nozzle. To create the pressure required for the airflow to reach speeds up to Mach 2.0, a seven-stage motor-driven compressor located inside the tunnel loop is used. Surrounding the test section walls, a balance chamber is used to provide boundary layer control of the airflow in the test section through perforations in the test section walls. The tunnel can operate at speeds from 0 to Mach 0.1 and from Mach 0.26 to 2.0.
The facility operates either in an aerodynamic closed-loop cycle, testing aerodynamic performance models, or in a propulsion open-loop cycle that tests live fuel burning engines and models. In the propulsion cycle, the tunnel operates by continuously drawing outside air through an air dryer and exhausting it back into the outside environment after it exits an acoustic muffler. This cycle is critical for models that introduce contaminants into the air or use potentially explosive gas mixtures. No exhaust scoop is required in this cycle.
To maximize data quality and minimize operational costs, the facility is controlled and monitored by a digital distributed control system. Steady-state data is collected from model instrumentation, processed and displayed real-time in engineering and graphical formats at an update rate of once-per-second. Transient data with sampling rates of 2 MHz/sec and an optical instrumentation suite of capabilities are available. To increase test productivity, a test matrix sequencer automatically changes model variables by using a pre-programmed test matrix. Real time transfer and display of all test data and information can be provided to customer locations outside of NASA Glenn.
Model supports available in the facility include a ceiling and floor strut for both supersonic and transonic test sections and a wall mount for large or half-span models.
