Aerodynamic parametric data of annular diffuser flow field for gas turbine engines are not available in sufficient detail. They are badly needed for future high efficiency engine design. A subsonic, axisymmetric, annular diffuser model was designed for the purpose of making such highly detailed information available. The objective of the design was to approximate an actual gas turbine engine diffuser. The diffuser was built according to these design specifications. The instrumentation required to gather the necessary pressure, velocity, and turbulence parameters consisted of three pitot tube systems, a hot wire anemometer system and a laser doppler velocimeter (LDV) system using frequency counting. These three instrumentation systems were integrated into the diffuser to obtain data at each of three points along the longitudinal axis. At each point there were five stations along the annulus that were instrumented. A longitudinal traversing structure utilizing motorized traversers for radial positioning and the capability to integrate absolute encoders was used to access the flow area.