AEDC supports JSF program with store separation test

ARNOLD AFB, TENN -- An Arnold Engineering Development Center test team and their Lockheed Martin customer are currently testing the F-35 Joint Strike Fighter in the center's 4-foot transonic wind tunnel to evaluate separation of weapons from the aircraft while in flight, helping keep the Joint Strike Fighter (JSF) program on track to meet initial production in 2006.
These store separation tests are focusing primarily on release from the aircraft's internal weapons bay, but have also included testing of the external fuel tanks as well.
Store separation testing evaluates how a weapon, fuel tank or other object will separate from an aircraft while in flight at different air speeds and angles of flight.
The testing is vital in the development of this next-generation attack aircraft to be used by not only the U. S. Air Force, but also by the Marines, Navy, and several foreign Air Forces including the United Kingdom.
The current test in the 4-foot transonic wind tunnel is evaluating the separation characteristics of the AIM-120 advanced medium-range air-to-air tactical missile (AMRAAM), the GBU-32 guided air-to-surface weapon Joint Direct Attack Munition (JDAM) 1,000-pound bomb, the GBU-12 air-to-surface guided glide bomb Paveway II and the C-13 external fuel tanks.
"Grid runs are performed by putting the weapon in a grid pattern around the aircraft to get a complete picture underneath the aircraft to see aerodynamically what the flow field is like," said Marc Skelley, senior project manager for the AEDC Flight Systems Test division. "Computational analyses are conducted from the grid run data and can help predict trajectories of the weapon's separation."
"This round of testing is the fifth conducted in AEDC wind tunnels since Lockheed Martin won the JSF contract in 2001," said Skelley. "When this testing is completed, 1,700 hours of tunnel test time will have been completed on just store separation since the system design and development phase began. This test is currently meeting the customer's expectations just as the four previous rounds of testing have done."
David Merrill, Lockheed's lead project manager, echoed that belief when commenting on the experience and expertise that AEDC provides during critical testing in the JSF program.
"AEDC has a great amount of experience on its staff in the Propulsion Wind Tunnel and with captive trajectory system testing," he said. "We rely on AEDC's engineers for their input and guidance and we probably wouldn't be able to do this test without their staff."
Besides the original X-35 prototypes built by Lockheed Martin, there are no current production aircraft to use for data acquisition. The current test articles are designed from computer-generated models with production of the actual aircraft scheduled at a later date.
"What we do here at AEDC is research and development and we are at the cutting edge of these new designs," said Skelley. "We are here to see what kind of problems the design might have and then to help make any improvements, if needed, before aircraft production begins."
After the JSF program begins production and the aircraft starts flight testing, AEDC's involvement will not completely cease. The center works closely with flight testers at Edwards Air Force Base, Calif., and Eglin Air Force Base, Fla., to provide seamless test and evaluation for the customer. Under this process, AEDC team members can be part of the flight test team at these other Air Force Materiel Command bases to provide ground test knowledge at the site and return test feedback to AEDC to further refine testing processes.