An apparatus for a unique wind tunnel useable for testing aerospace specific sensors and probes is presented. The apparatus utilizes an effective variable nozzle, allows testing of aerospace devices over a near infinite Mach and Reynolds numbers in subsonic flow. The variable nozzle allows for quick and easy adjustment over a minimum 1×10{circumflex over ( )}7 range of Reynolds number conditions from flow velocity of Mach 0.01 to 0.99. The optimal design of the apparatus allows for adaptation to different size test tunnels, using existing facilities to reduce cost, enabling various aerospace design applications. The apparatus of the present invention, provides a highly variable test environment in order to improve the development of advanced aerospace sensors, including benefits such as: development of flow sensors to prevent compressor stall; development of optical sensors to optimize turbine and compressor airflow; and, development of temperature sensors to increase efficiency of turbine engine operation.