HELICOPTER ROTOR DISK AND BLADE ELEMENT COMPARISONS

MODERN COMPUTER TECHNOLOGY OFFERS THE CAPABILITY TO PERFORM REAL-TIME PROCESSING OF MATHEMATICAL MODELS FAR MORE SOPHISTICATED THAN THOSE CURRENTLY BEING UTILIZED IN TRAINING APPLICATIONS. THE CAPABILITY TO COST EFFECTIVELY IMPLEMENT BLADE ELEMENT ROTOR MODELS IN REAL TIME USING MULTIPROCESSOR ARCHITECTURES AND RISC TECHNOLOGY PROCESSORS HAS BEEN DEMONSTRATED. IN ORDER TO EFFECTIVELY UTILIZE THIS NEW COMPUTATIONAL CAPABILITY IT IS NECESSARY TO ASSES THE TRADE-OFFS BETWEEN INCRESED FIDELITY AND THE COST ASSOCIATED WITH ADDED SOPHISTICATION IN ROTORCRAFT MATHEMATICAL MODELING. THE OBJECTIVE OF THIS STUDY IS TO PERFORM OFF-LINE COMPARISONS OF BLADE ELEMENT AND ROTOR MAP MODELS UNDER OTHERWISE IDENTIFICAL CONDITIONS TO ASSESS THE SIGNIFICANCE OF THIS INCREASED SOPHISTICATION TO SIMULATION FIDELITY AND TO WEIGH IT AGAINST THE ADDITIONAL COST ASSOCIATED WITH THE INCREASED COMPUTATIONAL REQUIREMENTS. THE COMPARISON WILL BE CONDUCTED USING THE FLIGHTLAB SYSTEM TO PROVIDE A MODULAR APPROACH TO REPLACING ONLY THE ROTOR MODEL IN A CONFIGURED SIMULATION. BLADE ELEMENT MODELS WILL BE COMPARED WITH ROTOR MAP MODELS AND AVAILABLE FLIGHT TEST DATA FOR BOTH THE MAIN AND TAIL ROTORS OF A UH-60 BLACK HAWK. COMPARISONS OF TRIM, STATIC STABILITY, TRANSIENT RESPONSE AND FREQUENCY RESPONSE WILL BE USED TO EVALUATE THE MODELS. HANDLING QUALITIES COMPARISONS WILL BE MADE USING THE NEW ADS33C HELICOPTER HANDLING QUALITIES SPECIFICATIONS. COMPARISONS WILL BE MADE BOTH FOR NOMINAL FLIGHT CONDITIONS AND AGGRESSIVE, EDGE-TO-THE-ENVELOP MANEUVERS.