HANDLING QUALITIES of the Lockheed Martin/Boeing F-22 are to be evaluated in flight tests of the US Air Force's variable-stability in-flight simulator aircraft (VISTA), a modified Lockheed Martin F-16. The Calspan-operated VISTA/F-16 will be programmed with the F-22's flight- control laws for a series of 30 flights beginning later this month.
The 42h programme will be used to evaluate the F-22's handling qualities in offset approaches, formation flying and simulated aerial refueling. The tests will determine the "robustness" of the F-22 flight-control system - its ability to handle any difference between predicted and real response - by varying the aerodynamics and structural stiffness to see if the aircraft continues to fly well. "Our simulator says the F-22 is very robust. The VISTA/F-16 will help confirm this," says F-22 chief test pilot Paul Metz.
One USAF and three contractor test pilots will fly the VISTA/F-16. In addition, two USAF pilots unfamiliar with the F-22 will conduct a "blind" evaluation of the VISTA/ F-16 to ensure that pilots familiar with the aircraft have not overlooked handling-quality deficiencies while developing the control laws. "Some of our pilots have spent hundreds of hours in the simulator developing the F-22. The aircraft appears to have exceptionally good handing qualities at this stage," Metz says.
Evaluation pilots will fly the VISTA/F-16 from the front cockpit using a variable-feel side stick programmed to represent the F-22 side stick. Commands from the stick, rudder pedal and throttle will be processed by one of two computers in the NF-16D's variable-stability system, which will be programmed with the F-22's control laws and, which will drive the aircraft's digital flight-control system. A safety pilot will occupy the rear cockpit.