Finessing Wind

Arnold Engineering Development Complex at Arnold AFB, Tenn., finished a two-year, $33 million upgrade to wind tunnel 4T, used for aircraft weapon-separation testing, officials announced. “Part of our work included an extensive calibration effort,” said senior engineer Mike Mills.”F-15 model data was compared with a historical data set; the typical centerline pipe tunnel calibration was expanded beyond what has been done in the past to further characterize the tunnel flow quality,” he added. The transonic tunnel also was completely stripped and refit with a new data processing, finely adjustable nozzles, automatic attitude adjustment, among other updates. The modifications standardize the tunnel’s analytics with AEDC’s Von Karman facility tunnels, and expand its testing capabilities, according to a Feb. 4 AEDC’s release. AEDC engineers and technicians designed, built, and installed the modifications, which took seven years from concept to completion. The tunnel is capable of velocities between 0.5 Mach and 2.5 Mach, and has already returned to service.