The Subsonic Wind Tunnel (15) is a closed-circuit tunnel having a test section of length 135cm and a cross-section of 50cm×50cm. It is operated by a 20 KW electric motor connected to a one-stage centrifugal fan. The control system of the fan permits to change its rotational speed continuously up to 1500 rpm. As a result, the air speed in the test section may reach a maximum of about 50 m/sec (Reynolds Number – up to 3 ×106 /meter). The turbulence level is less than 0.1%. The contraction nozzle has an area ratio of 5.76.