Engine/Inlet Compatibility Analysis Procedure

New analysis and testing techniques have been developed during the past five years to identify and fix potential compatibility problems before flight. These techniques are described, and examples of compatibility data are given for a supersonic inlet and a turbofan engine. The engine/inlet interface is defined in terms of maximum time-variant distortion and time-averaged inlet pressure. Model inlet test data and engine component data are combined by dynamic simulation to audit compatibility and to identify components which need improvement. Compatibility audits also include the effects of control transients, component interactions, Reynolds number and engine-to-engine variations. Tests become more sophisticated as components become better developed. Engine testing with distortion simulated by simple inlet screens is replaced by more expensive but more realistic testing with an inlet simulator. Individual component testing evolves into dual-spool testing and engine testing. The final proof of compatibility requires combined inlet and engine testing. By this time, the data bank should contain sufficient knowledge to assist in quick identification and solution of any new problems.