2017 marked one hundred years for Langley Research Center! In this photograph taken on March 30, 1990 shows one of the two 34-foot-diameter fans in the 16-Foot Transonic Tunnel. The Transonic Dynamics Tunnel (TDT) is a closed-circuit, continuous-flow, variable-pressure wind tunnel capable of using either air or R-134a as a test medium. The TDT is dedicated to identifying, understanding, and solving aeroelastic issues confronting fixed wing aircraft, helicopter, and tiltrotor configurations. Credit: NASA #nasa #research #engineering #nasalangley100 #tbt