HIGH-SPEED WIND TUNNEL TESTS OF A HIGH BYPASS LIFT/CRUISE FAN PROPULSION SYSTEM
Final rept. Mar 1963-Jan 1966
GENERAL ELECTRIC CO CINCINNATI OH ADVANCED TECHNOLOGY PROGRAMS DEPT
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An investigation was carried out to determine the aerothermodynamic characteristics of a family of close-coupled liftcruise fan installations. The liftcruise installation consisted of the General Electric X376 tip turbine fan system driven by a T58-6A core engine acting as a gas producer, and a nacelle system comprised of a family of interchangeable inlet and exhaust systems. The characteristics were obtained for Mach numbers between 0.0 and 0.85. The test results showed that the low-speed drag coefficient of the nacelle system including core engine was between 0.04 and 0.08, depending on the nacelle geometry and the inlet mass flow ratio. Drag rise or drag divergence occurred at lower than predicted test Mach numbers because of premature critical flow in the region of a nacelle fairing between fan and engine. The axisymmetric regions of the fan nacelle and the core engine nacelle demonstrated critical Mach number performance as obtained using standard nacelle design procedures. The test results provide criteria for redesign of the fairing regions to eliminate the premature critical flow conditions in this region of the installation. Analysis and recommendations for fairing and inlet lip design changes are provided small scale unpowered model tests would be needed to verify the analysis.
- Jet and Gas Turbine Engines