United States Air Force Test Pilot School Simulations
October 31, 2019
Simulated Vista Aircraft in formation flight
The United States Air Force (USAF) Test Pilot School (TPS) Class 19A and the Calspan Corporation conducted a simulation experiment on NASA Ames Research Center's Vertical Motion Simulator (VMS) as part of a student test management project (TMP). The project, named “Hasta La Vista,” was designed to investigate the effects of forward instantaneous centers of rotation (ICRs) on aircraft handling qualities. Data collection took place September 16-19, 2019, with four TPS student pilots.
When a pilot commands an aircraft to climb, the vehicle does not rotate about its center of gravity (CG), but rather, about a point known as the ICR. For traditional aircraft, this point is usually slightly behind the cockpit, and the pilot perceives a positive normal acceleration when initiating the climb. However, in some aircraft with unconventional wing geometries—like the Space Shuttle—the same climb command initially causes some loss of total lift and results in the aircraft sinking downward before climbing upward. Thus, the aircraft rotates about an ICR that is well forward of the cockpit, creating confusing and non-standard acceleration cues for the pilot.
This phenomenon poses a significant handling qualities challenge for the design of future unconventional geometry aircraft. While there is overwhelming evidence that forward aircraft ICRs negatively affect handling qualities during landing, there have not been any studies to determine the extent of this issue during up-and-away tasks, such as aerial refueling and formation tracking. Many aircraft designs in the future may have an ICR forward of the pilot station. The results from this project will be valuable in the formulation of new design guidelines for these vehicles.
(POC: Steve Beard)
View from the F16 VISTA aircraft during refueling task