Designing for Durability in Fighter Engines

Aircraft fighter engine design is a tradeoff between performance, reliability/durability, weight, and cost. The performance including operability and, more recently, survivability, can largely be determined early in the development program. “Shake and bake” component testing followed by Accelerated Mission Testing (AMT) can go a long way in the development of overall reliability. Engine weight and manufacturing cost can also be determined up front with reasonable certainty. However, durability or life is not readily determined during development and remains a promise to be designed into the engine to achieve the life requirements and reasonable cost of ownership. It can be argued that durability, heavily dependent on the mission duty cycle, is also closely linked to reliability, maintainability, and safety. Designing for durability includes “starting off on the right track” with the initial configuration, the selection of reliable and dependable damage tolerant materials and manufacturing processes, a rigorous structural analyses, and overall attention to detail. This paper describes an art and science “lessons learned” approach developed during the past 25 years to accommodate rapid throttle maneuver transients encountered in the aircraft fighter engines.