Accession Number : ADA182143

Title :   Frequency-Response Identification of XV-15 Tilt-Rotor Aircraft Dynamics.

Descriptive Note : Doctoral thesis,

Corporate Author : NATIONAL AERONUATICS AND SPACE ADMINISTRATION MOFFETT FIELD CA AMES RESEARCH CENTER

Personal Author(s) : Tischler,Mark B

PDF Url : ADA182143

Report Date : May 1987

Pagination or Media Count : 192

Abstract : Timely design and development of the next generation of tiltrotor aircraft (JVX) depend heavily on in-depth understanding of existing XV-15 dynamics and the availability of fully validated simulation models. Objects of the present study are: 1. Documentation and evaluation of XV-15 bare-airframe dynamics; 2. Comparison of aircraft and simulation responses; and Development of a validated transfer-function description of the XV-15 needed for future studies. A nonparametric frequency-response approach is used which does not depend on assumed model order or structure. Transfer-function representations are derived which fit the frequency responses in the bandwidth of greatest concern for piloted handling-qualities and control-system applications. Flight tests on the VX-15 aircraft and piloted-simulation for four flight conditions from hover to cruise were planned and executed. Improved test techniques and pilot-training procedures were devised. Analytical software tools allow the identification of high-resolution spectural responses and the derivation and validation of multi-input/multi-output transfer-function models. These techniques were applied in an extensive evaluation of the open-loop flight dynamics of the XV-15 aircraft and simulation mathematical models. Deficiencies in the mathematical models were exposed and documented.

Descriptors :   *TILT ROTOR AIRCRAFT, *FREQUENCY RESPONSE, FLIGHT TESTING, HIGH RESOLUTION, IDENTIFICATION, DYNAMICS, FLIGHT, COMPUTER PROGRAMS, MATHEMATICAL ANALYSIS, HOVERING, MATHEMATICAL MODELS, INPUT, MULTIPLE OPERATION, OUTPUT, TRANSFER FUNCTIONS, AERODYNAMIC STABILITY, AERODYNAMIC CHARACTERISTICS, FLIGHT CONTROL SYSTEMS, PILOTS, FLIGHT TRAINING, HANDLING, THESES, OPEN LOOP SYSTEMS, RESPONSE, SIMULATION, TIMELINESS, COMPUTERIZED SIMULATION, TEST METHODS, VALIDATION

Subject Categories : V/STOL
      Aerodynamics
      Flight Control and Instrumentation

Distribution Statement : APPROVED FOR PUBLIC RELEASE