ADVANCED GAS TURBINE ENGINE OPERABILITY

FUTURE AIRCRAFT MAY INCORPORATE POST-STALL MANEUVERABILITY DESIGN FEATURES TO PROVIDE A TACTICAL ADVANTAGE FOR AIR COMBAT MANEUVERING. POST-STALL MANEUVERABILITY IS CHARACTERIZED BY RAPID AND LARGE CHANGES IN AIRSPEED, ANGLEOF-ATTACK AND SIDESLIP. POST-STALL MANEUVERABILITY IS THE RESULT OF TWO PROPULSION SYSTEM FEATURES: AN ENGINE THATHAS A HIGH THRUST-TO-WEIGHT RATIO AND THE AVAILABILITY OF THRUST VECTORING. THE PROPULSION CONTROL SYSTEM MUST BE DESIGNED TO PROTECT THE ENGINE FROM A COMPRESSOR STALL THAT COULD RESULT FROM FLIGHT WITH EXTREME, OFF-AXIS INLET INFLOW ANGLES, AND IT SHOULD BE DESIGNED TO PROVIDE A LINEAR DYNAMIC THRUST RESPONSE TO PILOT GENERATED THROTTLE COMMANDS. A MODEL FOLLOWING PROPULSION CONTROL SYSTEM IS PROPOSED TO SATISFY THESE DESIGN REQUIREMENTS. THE FORWARD PATH MODEL COMPRISESTHREE SEPARATE MODELS. A TRANSIENT MODEL WILL BE USED TO GENERATE ATHRUST RESPONSE THAT HAS THE DESIRED RESPONSE PROPERTIES. A SECOND MODEL WILL BE USED TO MAP INLET CONDITIONS TO A REQUIRED COMPRESSOR STALL MARGIN. THE THIRD MODEL COMBINES ENGINE PERFORMANCE MAPS AND ANONLINE OPTIMIZATION ALGORITHM. TO ESTABLISH THE FEASIBILITY OF THEPROPOSED APPROACH, A PRELIMINARY DESIGN WILL BE PERFORMED, AND ITS PERFORMANCE WILL BE EVALUATED.