Download or read book Frequency response Identification of XV 15 Tilt rotor Aircraft Dynamics written by Mark B. Tischler and published by . This book was released on 1987 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Modeling XV 15 Tilt rotor Aircraft Dynamics by Frequency and Time domain Identification Techniques written by and published by . This book was released on 1986 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: Models of the open-loop hover dynamics of the XV-15 Tilt-Rotor Aircraft are extracted from flight data using two approaches: frequency-domain and time-domain identification. Both approaches are reviewed and the identification results are presented and compared in detail. The extracted models compare favorably, with the differences associated mostly with the inherent weighting of each technique. Step responses are used to show that the predictive capability of the models from both techniques is excellent. Based on the results of this study, the relative strengths and weaknesses of the frequency and time-domain techniques are summarized, and a proposal for a coordinated parameter identification approach is presented. (Author).
Download or read book Identification and Verification of Frequency Domain Models for XV 15 Tilt Rotor Aircraft Dynamics written by M. B. Tischler and published by . This book was released on 1984 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: Frequency-domain methods are used to extract the open-loop dynamics of the XV-15 tilt-rotor aircraft from flight test data for the cruise condition (V = 170 knots). The frequency responses are numerically fitted with transfer function forms to identify forms to identify equivalent model characteristics. The associated handling quality parameters meet or exceed Level II, Category A, requirements for fixed-wing military aircraft. Step response matching is used to verify the time-domain fidelity of the transfer-function models for the cruise and hover flight conditions. The transient responses of te model and aircraft are in close agreement in all cases, except for the normal acceleration response to elevator deflection in cruise. This discrepancy is probably due to the unmodeled rotor rpm dynamics identification and analysis is clearly demonstrated. Keywords: Tilt-Rotor aircraft; Parameter identification; Flight testing; Frequency-domain methods; Transfer function identification.
Download or read book The History of the XV 15 Tilt Rotor Research Aircraft written by Martin D. Maisel and published by . This book was released on 2000 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Identification of XV 15 Aeroelastic Modes Using Frequency Domain Methods written by and published by DIANE Publishing. This book was released on 1989 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Simulation of the XV 15 Tilt Rotor Research Aircraft written by and published by . This book was released on 1982 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Helicopter Flight Dynamics written by Gareth D. Padfield and published by John Wiley & Sons. This book was released on 2018-09-07 with total page 856 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Book The behaviour of helicopters and tiltrotor aircraft is so complex that understanding the physical mechanisms at work in trim, stability and response, and thus the prediction of Flying Qualities, requires a framework of analytical and numerical modelling and simulation. Good Flying Qualities are vital for ensuring that mission performance is achievable with safety and, in the first and second editions of Helicopter Flight Dynamics, a comprehensive treatment of design criteria was presented, relating to both normal and degraded Flying Qualities. Fully embracing the consequences of Degraded Flying Qualities during the design phase will contribute positively to safety. In this third edition, two new Chapters are included. Chapter 9 takes the reader on a journey from the origins of the story of Flying Qualities, tracing key contributions to the developing maturity and to the current position. Chapter 10 provides a comprehensive treatment of the Flight Dynamics of tiltrotor aircraft; informed by research activities and the limited data on operational aircraft. Many of the unique behavioural characteristics of tiltrotors are revealed for the first time in this book. The accurate prediction and assessment of Flying Qualities draws on the modelling and simulation discipline on the one hand and testing practice on the other. Checking predictions in flight requires clearly defined mission tasks, derived from realistic performance requirements. High fidelity simulations also form the basis for the design of stability and control augmentation systems, essential for conferring Level 1 Flying Qualities. The integrated description of flight dynamic modelling, simulation and flying qualities of rotorcraft forms the subject of this book, which will be of interest to engineers practising and honing their skills in research laboratories, academia and manufacturing industries, test pilots and flight test engineers, and as a reference for graduate and postgraduate students in aerospace engineering.
Download or read book Monthly Catalog of United States Government Publications written by and published by . This book was released on 1991 with total page 828 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Monthly Catalogue United States Public Documents written by and published by . This book was released on 1991 with total page 1690 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1988 with total page 1020 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Determining XV 15 Aeroelastic Modes from Flight Data with Frequency domain Methods written by and published by . This book was released on 1993 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Technical Reports Awareness Circular TRAC written by and published by . This book was released on 1987 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1986 with total page 1066 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Vertica written by and published by . This book was released on 1990 with total page 636 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Research and Technology Annual Report written by Earth Resources Laboratory (U.S.) and published by . This book was released on 1987 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book NASA Technical Memorandum written by and published by . This book was released on 1963 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Using Frequency domain Methods to Identify XV 15 Aeroelastic Modes written by and published by . This book was released on 1987 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: The XV-15 Tilt-Rotor wing has six major aeroelastic modes that are close in frequency. To precisely excite individual modes during flight test, dual flaperon exciters with automatic frequency-sweep controls were installed. The resulting structural data were analyzed in the frequency domain (Fourier transformed) with cross-spectral and transfer-function methods. Modal frequencies and damping were determined by performing curve fits to transfer-function magnitude and phase data and to cross-spectral magnitude data. Results are given for the XV-15 with its original metal rotor blades. Frequency and damping values are also compared with earlier predictions. Keywords: Tilt rotor aircraft.
