AEROPROPULSION SYSTEMS TEST FACILITY
Published February 19, 2009
The Aeropropulsion Systems Test Facility at the Air Force's Arnold Engineering Development Center, located at the Arnold Air Force Base in southern Middle Tennessee, is a unique national facility designed to test aircraft propulsion systems in true mission environments without leaving the ground.
ASTF is part of AEDC's Engine Test Facility, which has established the center as the USAF center of expertise in turbine engine testing. Located on a 57-acre site, ASTF is an open-circuit facility with two test cells, designated C-1 and C-2, each 28-feet in diameter and 85-feet long. For comparison, the next largest ETF test cell is 20-feet in diameter and 60-feet long.
The facilities unique features permit data to be acquired in ground testing that was previously available only after extensive flight testing.
ASTF provides the United States with the unique test capability of simulating flight conditions at altitudes up to 75,000 feet, at speeds up to Mach 2.3, for engines rated up to 100,000 pounds of thrust.
The air supply compressors can provide up to 1,500 pounds of air per second (more than one-million standard cubic feet per minute) into the test cell to simulate airspeeds up to 1,800 miles per hour. The compressors, totaling 215,000 horsepower, are started by one of the largest variable frequency starting systems in the world. An additional 960 pounds per second of airflow is available by drawing outside air directly into the C-2 test cell.
Providing properly conditioned air to the propulsion systems to simulate supersonic flight conditions calls into play the largest air heaters in the world. These heaters can burn either diesel fuel or waste aviation fuel and generate enough heat (one billion BTUs per hour) to raise the temperature of the airflow to a maximum of 450 degrees Fahrenheit (350 degrees at the test cell).
Exhaust gases can reach temperatures of nearly 3,500 degrees Fahrenheit and must be cooled before they go through the exhaust machinery and are vented into the atmosphere. In its current configuration, initial cooling is done by direct-contact water spray, which reduces the temperature to 200 degrees Fahrenheit. Another water spray cools and cleans the exhaust gas to less than 150 degrees Fahrenheit before it enters the exhaust compressors. Cooling of the exhaust gases requires up to 25,000 gallons of water per minute. Total facility cooling water capability is 387,000 gallons per minute. Cooling towers are used to cool and recirculate a three-million gallon, closed-circuit reservoir of water that is used during testing operations.
The Pratt & Whitney F119 power plant for the F-22A Raptor Air Dominance Fighter has been extensively tested in ASTF since 1989. The P&W F135 primary engine and the GE/Rolls-Royce Fighter Engine Team F136 alternate engine for the F-35 Lighting II Joint Strike Fighter will be testing at AEDC for the next several years.
In addition to testing military propulsion system, ASTF has been instrumental in making America more competitive in the international market. The congressionally enacted law allowed U. S. government agencies and facilities to open their doors and technology to American industry. The P&W 4000 series engines for the Boeing 777 was tested in the 1990's. Recent commercial engine tests include the GE P&W Engine Alliance GP 7200 for the Airbus A380 to determine the engine operational characteristics and qualify it for flight passenger airliner and the P&W 6000 engine.
In addition, the Rolls-Royce Trent 800 engine for the Boeing 777, the Trent 900 for the Airbus A380, and the Trent 1000 for the Boeing 787 have also been tested at ASTF. Recently, the Ishikawajima-Harima Heavy Industries XF7-10 engine was tested for the Japan Ministry of Defense through the USAF Foreign Military Sales office. The IHI XF7-10 is used in the Kawasaki P-1 maritime patrol aircraft which is the first Japanese locally designed and built combat aircraft since World War II.
Identified by a joint NASA and Department of Defense Aeronautics and Astronautics Coordinating Board in the 1960s as essential to the nation, ASTF was designed for testing integrated, full-scale propulsion systems under simulated flight conditions that are more realistic than ever before. Construction begun in 1977, took seven years to complete and involved as many as 1,000 workers. Following integration and activation, the facility reached initial operational capability in September 1985.