This document reviews the state of the art for data scaling issues associated with air induction system development for turbine-engine-powered aircraft. In particular, the document addresses issues with obtaining high quality aerodynamic data when testing inlets. These data are used in performance and inlet-engine compatibility analyses. Examples of such data are: inlet recovery, inlet turbulence, and steady-state and dynamic total-pressure inlet distortion indices. Achieving full-scale inlet/engine compatibility requires a deep understanding of three areas: 1) geometric scaling fidelity (referred to here as just “scaling”), 2) impact of Reynolds number, and 3) ground and flight-test techniques (including relevant environment simulation, data acquisition, and data reduction practices). The Model-to-Full Scale Subcommittee of the S-16 Turbine Engine Inlet Flow Distortion Committee has examined archives and has obtained recollections of experts regarding air induction system development experience to produce this document.
The intent of this document is to capture the experience and lessons learned since approximately 1967 necessary to ensure that model-scale inlet total-pressure recovery and distortion data faithfully represent the corresponding full-scale inlet recovery and distortion characteristics.