DFRC - Research - Facilities - Research Aircraft Integration Facility - Introduction
April 13, 2011
IntroductionTesting in the RAIF is done by using automated techniques to interface a research aircraft to a high-fidelity, real-time simulation. Electric and hydraulic power are also supplied, allowing all systems except the engines to function as if in flight. The testing process is controlled by an engineering workstation programmed to set up initial conditions for a test, initiate the test run, monitor its progress, and archive the data generated. Workstations are also used to analyze results of individual tests, compare results of multiple tests, and produce reports.
The computers used in the automated aircraft testing process can also operate in a stand-alone mode with a simulation cockpit, complete with its own instruments and controls. Control law development and modification, aerodynamics, propulsion, guidance model qualification, and flight planning - functions traditionally associated with real-time simulation - can all be performed in this manner.
The Remotely Augmented Vehicles (RAV) laboratory is a mainstay among the research facilities used at Dryden. This lab is used for a variety of applications, including tests that are too hazardous for direct human involvement or for which computational capacity does not exist onboard a research aircraft. The RAV lab provides the researcher with ground-based computers that are radio frequency linked to the test aircraft during actual flight.
The Ground Vibration Testing (GVT) laboratory resides in the RAIF. In preparing a research aircraft for flight testing, the GVT provides vital measurements of its structural frequencies and mode shapes and compares results to the models used in design analysis.
The final critical function performed in the RAIF is routine aircraft maintenance. This includes pre-flight and post-flight instrumentation checks and the servicing of hydraulics, avionics, and engines necessary on any research aircraft. Aircraft are not merely moved to the RAIF for automated testing purposes but are housed there throughout their flight test programs.
The configuration of the RAIF test bays (hangars) provides flexibility in housing large, commercial size, or smaller aircraft. Six aircraft test stations are provided in three physical areas. Each area can be configured to support classified projects. Door clearance is 15 x 68 m (50 x 225 ft) across test bays 1, 2, and 3; 12 x 38 m (40 x 125 ft) across test bays 4 and 5; and 12 x 30 m (40 x 100 ft) across test bay 6. Structural provisions were made for future installation of a 18 metric ton (20 english ton) overhead crane in test bays 1, 2, and 3 and 9 metric ton (10 english ton) overhead cranes in test bays 4, 5, and 6. The floors in test bays 2 and 6 contain tie-down slots 1.2 m (4 ft) apart to anchor GVT test setups. The slots are designed to anchor forces up to 140 kN/m (9500 lb/linear ft).
A control room on the second floor overlooks each test bay. Windows and closed circuit video links are available to remotely monitor tests in progress. Simulation hardware is located in these control rooms. This allows short line lengths between aircraft and computer hardware for closed-loop simulation with the flight vehicle. The general and secure simulation areas, RAV lab, storage, and computer maintenance facilities are also housed on the second floor.
Aircraft technicians and maintenance personnel occupy the first floor of the center section, and both floors in the front section are occupied by engineering and facility management personnel. The RAIF also contains several conference rooms on the first and second floors.
Aircraft services, including electrical power, hydraulic supplies, and cooling air, are provided to support routine maintenance and aircraft-in-the-loop simulation. All services can be monitored by computer in real time when performing aircraft tests. Electric power provided includes 277/480 VAC and 120/208 VAC, three phase, at 60 Hz; 120/208 VAC, three phase, at 400 Hz; and 28 VDC. An uninterruptible power source (UPS) supports the computer rooms and offices. Hydraulic systems serving the six test bays are independent, allowing different pressures and fluids to be used simultaneously. Every system contains 3 pumps, with each providing 130 liter/min (35 gal/min) at 34 MPa (5000 lb/in2). This provides a total flow of 400 liter/min (105 gal/min) at 34 MPa (5000 lb/in2). The flow per pump can be increased to 190 liter/min (50 gal/min) at 24 MPa (3500 lb/in2).
The RAIF also provides aircraft cooling in all test bays to control aircraft avionics systems temperatures. All test bays are air conditioned and heated for test equipment temperature stability and personnel comfort.
Flight research programs supported in the RAIF include the following:
AFTI F-16, APEX, F-15 ACTIVE, F-16XL DFLCS, F-16XL SLFC, F-18 HARV, F-18 SRA, NASP, Pathfinder, Perseus, Theseus, Tier 3- Darkstar, X-31 EFM, X-33 VentureStar®, X-34, and X-36.