Aircraft System One-Sixth Scale Model Studies. Coanda/Refraction Noise Suppression Concept. Advanced Development
Final technical rept. Aug 1974-Jan 1976
BOEING WICHITA CO KS
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The proven Coandarefraction concept is applied to the Navy requirement for effective exhaust noise suppression of aircraft installed engines ground run up tests. The technical approach is comprised of analytic studies and one-sixth scale model tests using simulated sources for single and twin-engine aircraft. The results of previous exploratory studies, using simulated static sources, are applied to the more complex situation with the engine tailpipe centerline displaced horizontally, vertically, longitudinally and angularly from the model suppressor inlet. Test runs at varied simulated engine power settings and varied model geometric orientations were conducted to determine the effects on jet attachment to the Coanda surface and on cooling air eduction. The extensive recorded test data were analyzed to identify aero thermodynamic trends related to suppressor internal components, ejector geometry and material cooling properties. Results present operational limits and configurations for further development as exhaust systems for aircraft test enclosures and aircraft run up suppressors.