|F-22 Enters New, More Stressful Phase of Static Testing at LMAS |
F-22 Enters New, More Stressful Phase of Static Testing at LMAS
MARIETTA, Ga. (May 24, 1999) -- The F-22 Raptor today began what could be the most stressful phase of its development program -- 100 percent design limit load testing of the air-superiority fighter's structural design integrity here at the Lockheed Martin Aeronautical Systems (LMAS) plant.
Photo: Lockheed Martin
Design limit load testing of the airframe will demonstrate that the complete structure is capable of carrying, without damage, the design loads the aircraft will encounter in its operational flight envelope. Data from these tests will also be used to validate and refine the computerized finite element structural analyses used in F-22 design.
Destined never to fly, the third Raptor assembled -- aircraft #3999 -- will serve as a static test vehicle to verify the analyses used in establishing the structural capability of the F-22 and, to certify the structural design integrity. Static test set-up activities actually began last year and continued concurrent with Raptor 3999's assembly operations. Preliminary loads calibration tests on control surface hinges, weapons bay doors, and pressure surveys of the airframe have been in progress since January 1999.
Static testing of Raptor 3999 is crucially important to the F-22's engineering and manufacturing development phase. During static testing, a team of test engineers, technicians, and mechanics will reproduce, record and measure the structural loads the F-22 will be subjected to during flight and by other conditions throughout the aircraft's operation. For example, simulated aerodynamic and inertial loading on the wings, vertical tails and fuselage structures, in combination with fuel tanks and inlet ducts pressurization will be applied in a scenario of load conditions of increasing severity.
These ground tests are also required to support the expansion of load envelopes on the flight test aircraft. As the flight test aircraft loads build-ups approach design levels it is necessary for strength levels to be verified on the ground first. Thus the flight and ground tests programs must proceed in a parallel manner.
The static test rig is a large (larger than the F-22 itself), steel-frame structure composed of approximately 200 hydraulic jacks that apply pressure to the F-22. The design limit load testing -- which is routine in nature -- is expected to take about four months.
The F-22 is being developed to counter lethal threats posed by advanced surface-to-air missile systems and next generation fighters equipped with launch-and-leave missiles. It is widely regarded as the most advanced fighter in the world, combining a revolutionary leap in technology and capability with reduced support requirements and maintenance costs. It will replace the F-15 as America's front-line, air superiority fighter, with deliveries to operational units beginning in 2002.
The F-22's combination of stealth, integrated avionics, maneuverability and supercruise will give Raptor pilots a first- look, first-shot, first-kill capability against the aircraft of any potential enemy. The F-22 is designed to provide not just air superiority, but air dominance, winning quickly and decisively with few U.S. casualties. The F-22 also has an inherent air-to-ground capability.
Lockheed Martin leads the contractor team working closely with the U.S. Air Force on the F-22 program. Air vehicle team members include LMAS, Lockheed Martin Tactical Aircraft Systems in Fort Worth, Texas, and Boeing. Pratt & Whitney provides the Raptor with its F119 supercruise engines.
Headquartered in Bethesda, Maryland, Lockheed Martin is highly diversified global enterprise principally engaged in the research, design, development, manufacture, and integration of advanced-technology systems, products and services. The corporation's businesses employ more than 170,000 people worldwide.
Lockheed Martin Aeronautical Systems
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