ASC’s MSRC supports study to improve F-22 fighter

  • Published
  • By Gary Sivak and Dinah Luneke
  • ASC Major Shared Resource Center
WRIGHT-PATTERSON AIR FORCE BASE, Ohio --  An enemy fighter jet in hot pursuit gains on an F-22 as the pilot instinctively pushes on the stick and the rudder pedals for a 90-degree turn to break away. The 9-G- plus forces tax the body of the seasoned fighter pilot, but will these stresses damage the body of the F-22 aircraft?

The Major Shared Resource Center here at Aeronautical Systems Center is supporting an F-22 Fighter Flight Worthiness study designed to answer this and other unforeseen operational questions. Brian Bohl of the F-22 Structures Certification Integrated Product Team -Loads and Criteria Team, Lockheed Martin Corporation, is leading the study.

"Due to schedule setbacks, our in-house computing resources were insufficient to complete the project on time," said Mr. Bohl. "Our F-22 program counterparts here at Wright-Patt recommended the ASC MSRC. After we reviewed this Center's high-performance computing capabilities and its top-rated service operation, we submitted this project to run there. With the 10,000 high priority hours assigned to us, along with the ASC MSRC's high performance computing capabilities, our project was completed on schedule."

The project's high-priority status arose from the need to release the Final Engineering Manufacturing Development (EMD) certification loads for the F-22 fighter airframe. EMD completion certifies to the customer that the aircraft meets design requirements and is safe for flight.

The EMD process drove airframe design and manufacturing development.

The F-22 design loads evolved from Computational Fluid Dynamics to measured wind tunnel loads, and ultimately to wind tunnel loads correlated with measured flight test data. The final EMD certification loads based on the correlated wind tunnel model were run on the HPC systems at the ASC MSRC.

"Flight test is used to verify each structural item's critical load; the uncorrelated analysis model tells us where to look for high loads in flight," Bohl reports. "Flight test either validates the predicted load level or points out shortfalls in the analysis. So, by correlating the analytical model with measured flight test data, we end up with a much more robust model."

The impacts of this study resulted in the F-22 Fighter being mission ready with fewer flight tests. The F-22 was released as certified to fly, which met the Initial Operational Capability milestone.

The research at the ASC MSRC was supported by the High Performance Computing Modernization Program that was initiated in 1992 in response to congressional direction to modernize the Department of Defense laboratories' HPC capabilities.

"It is important to understand that oftentimes it is far too dangerous to perform live aircraft testing," said Steve Wourms, director for ASC's Advanced Computational Analysis Directorate. "To perform simultaneous stressors on the aircraft at such extreme conditions is virtually impossible. High performance computing studies protect both the integrity of the aircraft and the pilot's life, while giving the exact information needed by the test team. We are proud of this research study at the ASC MSRC, which ultimately helped to clear the F-22 fleet for flight operation."