Application of Temperature Sensitive Paint for High Altitude Transonic Natural Laminar Flow Design – Part II

Otto Aerospace Inc. completed a test entry at the European Transonic Windtunnel to support design and tool validation efforts on a natural laminar flow concept for high altitude transonic flight. As part of this testing the use of cryogenic temperature sensitive paint along with other traditional measurement methods were applied to an 8-percent subscale wind tunnel model to capture and evaluate boundary layer transition across a wide range of flight relevant test conditions including variations in Mach number and Reynolds number. Cruise configuration performance via pitch sweeps were collected across a range of flight conditions, both inside and outside the intended design point. Building upon a previous publication this paper addresses the impacts of model lift coefficient for several flight conditions. The wind tunnel model design, development and fabrication were completed to provide the best possible conditions for boundary-layer transition characterization and general configuration performance. Test observations are made to provide results for ongoing computational predictions and provide specific areas for improvement and refining of Otto’s numerical methods and tools.