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Boeing 787; ~25 ft wingtip deflection
Wing ultimate load test complete on 787
Posted by Guy Norris at 3/29/2010 2:27 AM CDT
Boeing completed the ultimate limit-load test on the static test 787 airframe, ZY997, at Everett on March 28. The test – officially dubbed Condition 18b - evaluates the ability of the wing-body structure to sustain loads equal to 150% design limit load - or the most extreme forces ever expected to be seen in service, and its clearance marks the passing of a significant hurdle on the way to FAA certification.
During the test, which occurred with 14.9 psi fuselage pressure, the wingtips deflected upwards by approximately 25 ft. The test, which did not continue until the wings failed, was also a key evaluation of the strengthened side-of-body modification which in June last year caused a six-month delay to the start of 787 flight tests. The deflection of the higher-aspect ratio composite wing was greater than that of the metallic 777 wing, the last major primary structure to undergo “wing ultimate up-bending” tests in Boeing’s sprawling Everett site more than 15 years ago. The 777 wing failed at 154%, having deflected 24 ft.
Internally Boeing is hailing the test as a major success, though externally the company is sounding a note of caution. “The initial results of the ultimate-load test are positive. More extensive analysis and review are required before the test can be deemed a success,” says Boeing.
Posted by Guy Norris at 3/29/2010 2:27 AM CDT
Boeing completed the ultimate limit-load test on the static test 787 airframe, ZY997, at Everett on March 28. The test – officially dubbed Condition 18b - evaluates the ability of the wing-body structure to sustain loads equal to 150% design limit load - or the most extreme forces ever expected to be seen in service, and its clearance marks the passing of a significant hurdle on the way to FAA certification.
During the test, which occurred with 14.9 psi fuselage pressure, the wingtips deflected upwards by approximately 25 ft. The test, which did not continue until the wings failed, was also a key evaluation of the strengthened side-of-body modification which in June last year caused a six-month delay to the start of 787 flight tests. The deflection of the higher-aspect ratio composite wing was greater than that of the metallic 777 wing, the last major primary structure to undergo “wing ultimate up-bending” tests in Boeing’s sprawling Everett site more than 15 years ago. The 777 wing failed at 154%, having deflected 24 ft.
Internally Boeing is hailing the test as a major success, though externally the company is sounding a note of caution. “The initial results of the ultimate-load test are positive. More extensive analysis and review are required before the test can be deemed a success,” says Boeing.
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