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 LONG BEACH, Calif., Aug. 31 /PRNewswire/ -- McDonnell Douglas' C-17 successfully completed a major structural test Saturday (Aug. 28) in Long Beach. The fuselage of a non-flying C-17 was subjected to loading forces that were 150 percent of the aircraft's design limit load.
 Design limit loads are those forces that could be expected under a variety of extreme flight conditions. In order to provide standard aeronautical safety margins, an aircraft must be able to sustain certain test loading conditions that are 150 percent of design limit loads. These are called "ultimate" loads.
 "We were delighted with the results of this maximum test of the fuselage," said Dave Swain, McDonnell Douglas senior vice president and C-17 program manager. "Historically, such major component ultimate load tests have only a 50-60 percent probability of first time success."
 The aircraft was tested to provide a design gross weight capability of 585,000 pounds.
 In addition to Saturday's test, three successful ultimate load tests of the aft fuselage have been completed recently. In one test the aft fuselage section and vertical stabilizer successfully withstood maximum bending loads with the cargo door and ramp open. The next two tests subjected the vertical stabilizer and fuselage to maximum lateral bending loads with the cargo door and ramp closed, and then open.
 The main landing gear and horizontal stabilizer have had successful 150 percent design limit tests at subcontractor facilities belonging to Cleveland Pneumatics and Vought, respectively.
 Last October, the C-17 wings sustained damage in a test at approximately 125 percent of design limit load. Since then they have been strengthened. In mid-July, the wings were successfully tested to the same loads without failure. During Saturday's test, the area of the wing that failed last October sustained design limit loads of approximately 135 percent as the wing tips were deflected upward approximately 10 feet. The ultimate load test for the wings will occur in September.
 The simulated test condition for Saturday's fuselage ultimate load test was a 3g, steady-pitch, pull-up maneuver following a dive and at an airspeed of 381 knots with an altitude of 17,095 feet. A major portion of the airframe structure was critical for this test, including the forward, center and aft fuselage; the inner wing and wing carry-through structure; and the fuselage to vertical stabilizer spar attachments.
 The aircraft is situated in a large static test fixture where some 350 hydraulic actuators are used to apply load conditions to the fuselage, wings and other parts of the aircraft. More than 4,300 instruments collect stress, loads and deflection data that is fed into a computer for comparison with predicted values.
 Static testing at Long Beach is scheduled to be completed in early 1994.
 The U.S. Air Force plans to buy 120 C-17 Globemaster III military transports. Six are currently assigned to a flight test program at Edwards AFB, Calif. Two C-17s have been delivered to Air Mobility Command's operational 437th Airlift Wing at Charleston AFB, S.C.
 -0- 8/31/93
 /CONTACT: Larry McCracken or Jim Ramsey of McDonnell Douglas Aerospace, 310-522-2552 or 310-522-2567/

CO: McDonnell Douglas Aerospace ST: California IN: ARO SU:

BP-JL -- LA034 -- 7702 08/31/93 18:31 EDT
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Publication:PR Newswire
Date:Aug 31, 1993

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