Recent inmprovements to the NAE 5 ft x 5 ft blowdown wind tunnel

Abstract

Although the NAE 5 ft X 5 ft Blowdown Wind Tunnel was conceived in the 1950's, with commissioning in 1962/63, it has stood the test of time very well and is still, in 1985, in heavy demand. We may cite three main reasons for this situation: (i) the basic wind tunnel design was fundamentally very sound, (li) the wind tunnel circuit and its auxiliary systems have frequently been improved and modernized so that it, even today, is a modern up-to-date facility, (iii) the high level of competence of the supporting staff. In this report we present the major improvements made in recent years and the impact these have had on the performance of the facility. The improvements elaborated on are: •The rebuild of the settling chamber; •The rebuild of the exhaust diffuser; •The installation of active Mach number contral for subsonictransonic operation; •The incorporation of dual drive on the two-dimensional insert balance system; •The suppression of edgetone noise; •The incorporation of highly accurate digital pressure transducers; •The control and data processing system Finally, future plans for expanded utilization of the wind tunnel are outlined.