Arnold engineers test Army weapon to evaluate its capability Published Nov. 17, 2008 By Philip Lorenz III Arnold Engineering Development Center Public Affairs ARNOLD AIR FORCE BASE, Tenn. (AFNS) -- Arnold Air Force Base engineers conducted an aerodynamic test on the Army's Mid-Range Munition recently that provided a new and critically needed performance evaluation capability for current and potential test customers. The purpose of the test, which took place in the Arnold Engineering Development Center's four-foot transonic wind tunnel, was to determine the aerodynamic lift and drag forces and moments the guided projectile will experience in flight. What made this test unique was the successful operation of a novel remote control system that efficiently determined the projectile's performance limitations while saving the Army time and money in the process, said Charlie Smith, the project engineer for Aerospace Testing Alliance's integrated test and evaluation department. "A large amount of data was required to compare various configurations of the test article and determine performance, stability, and control effectiveness of the optimum configuration," he said. "Instead of just moving the projectile's control surfaces to a fixed position by remote control, we were able to automatically position the canards to maintain the measured projectile pitching, rolling, and yawing moments at a specified value, usually zero (trim), while simultaneously pitching and rolling the projectile at simulated flight conditions. We are approaching a 'fly the mission' capability with this development." Canards are moveable, wing-like structures located near the front of the projectile used to guide the projectile. Additional fixed-position fins are located at the rear of the projectile to provide stability and lift. The collaboration between ATA, the Air Force and the test community resulted in an improved capability that would have positive, long-term implications, said Dr. Richard Roberts, Arnold's Air Force project manager on the test. "We are excited to have this new test method," he said. "We were able to work closely with the community to help develop and integrate this method into our test process. The auto trim method will help save our customer's money and time, and has the potential to compress weapon and aircraft acquisition schedules by reducing the amount of time typically spent during wind tunnel testing and analysis. " According to officials at Raytheon, the contractor chosen to develop the Mid-Range Munition projectile, the weapon system is being designed to provide the Army with a lethal, one-shot capability as the service continues its transformation to lighter, more deployable combat forces. Comment on this story (comments may be published on Air Force Link) View the comments/letters page