STRUCTURAL TEST OF THE V-22 AIRFRAME WING/FUSELAGE

Structural fatigue testing is one of the requirements mandated by the military to qualify an airframe for service. The V-22 is unique in that it must successfully complete structural testing for not only fixed-wing criteria, but also rotary craft criteria. The unique nature of the V-22 presented load introduction and fixture design challenges that resulted in more complicated designs in some areas, while simplifying designs in others. This paper chronicles some of the design challenges and solutions utilized to complete structural testing on the V-22 airframe. The airframe test has successfully completed 20,000 effective flight hours of test after nine calendar years of testing. During the course of testing, many incidents were noted, ranging from items as minor as a rotated or failed fastener, to a few incidents requiring analysis and repair with the potential to optimize component design. Relatively few modifications were required to the test rig structure or test methodology, which may be interpreted to mean that the time spent up-front on the fixture design proved to be well spent. Structural testing has demonstrated the durability of the V-22 airframe, while presenting one of the greatest challenges to the test engineers.