The F-22 completes limit load testing as well as its final flight test criterion for the year.
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Raptor #3999 has completed the last of the F-22's planned static design-limit load tests. Destined never to fly, aircraft #3999 is a static test article used to verify and certify the F-22's structural design integrity and the analyses used to establish the aircraft's structural capabilities.
During the static tests, a team of engineers, technicians, and mechanics under Static Test Lead Engineer Kevin Cumbie reproduced, recorded, and measured responses to the structural loads an F-22 will be subjected to during flight and by other conditions throughout the aircraft's operation. Examples of static testing include the application of simulated aerodynamic and inertial loading on the F-22's wings, vertical tails, and fuselage structures, in combination with fuel tanks, cockpit, and inlet ducts pressurization. This latest and final static test was a combination of fuselage mechanical loading with pressurization of the inlet ducts to simulate a hammershock condition.
The results from these tests not only validated the F-22's airframe for operation, but also provided data that will be used to validate and refine the computerized finite element structural analyses used in the aircraft's design.
In addition to completing its last static test, the F-22 also demonstrated its fifth and final flight test criterion for the year. Raptor #4001, the first F-22 built, completed a 3-h sortie in which flutter envelope expansion and vibro-acoustic wind up-turns were accomplished over Edwards Air Force Base, CA. The flight represented the fighter's first substantial entry envelope-expansion zone E-4 and satisfied the remaining DoD flight-test criteria for 1999.
Frank Bokulich
