The drive system consists of a fan with variable inlet guide vanes for responsive Mach number control. In the variable temperature cryogenic mode, nitrogen is the test gas. In this mode, the NTF provides full-scale flight Reynolds numbers without an increase in model size. In the ambient temperature air mode, air is the test gas and a heat exchanger is used to maintain the tunnel temperature. The NTF provides tests in support of stability and control, cruise performance, stall buffet onset, and configuration aerodynamics validation.
Researchers also use the tunnel to determine the effects of ground-wind loads on launch vehicles.
The tunnel provides steady and unsteady aerodynamic pressure data to support computational aeroelasticity and computational fluid dynamics computer code development and validation. The TDT is a closed-circuit, continuous flow, variable pressure wind tunnel. The tunnel is capable of using either air or R-134a as the test medium. Testing in R-134a has important advantages over testing in air, particularly for aeroelastic models. The Langley Unitary Plan Wind Tunnel is a closed-circuit, continuous flow, variable density supersonic tunnel with two test sections.