Download or read book Theory Test Correlation of Helicopter Rotor Blade Element Airloads in the Blade Stall Regime written by Christopher J. Bobo and published by . This book was released on 1972 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Experimental Investigation of the Helicopter Rotor Blade Element Airloads on a Model Rotor in the Blade Stall Regime written by and published by . This book was released on 1971 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Correlation of Airloads on a Two bladed Helicopter Rotor written by Francisco J. Fernandez and published by . This book was released on 1993 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book In flight Measurement and Correlation with Theory of Blade Airloads and Responses on the Xh 51a Compound Helicopter Rotor written by J.E. Sweers and published by . This book was released on 1968 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book In flight Measurement and Correlation with Theory of Blade Airloads and Responses on the XH 51A Compound Helicopter Rotor written by and published by . This book was released on 1968 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The report presents the results of a two-phase research program consisting of (1) in-flight measurement of aerodynamic pressures and structural loads on a compound, rigid-rotor helicopter and (2) correlation of these data with theoretical results. Flight test data obtained in Phase I and recorded on an oscillograph were read on an oscillograph reading machine and were processed in an automatic data reduction program. This data processing consisted of integration of the pressure data to obtain the distribution of aerodynamic lift and pitching moments over the rotor blade, as functions of azimuth position. Airload and structural load data were harmonically analyzed. Output of the data reduction program was used in Phase II as input to the correlation program. The measured airloads were used to compute the theoretical bending and torsion responses of the blade. The measured torsion moments were used in the theoretical prediction of the airloads. The results of the applied theories are compared with the flight measurements.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1984 with total page 1278 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book In flight Measurement and Correlation with Theory of Blade Airloads and Responses on the XH 51A Compound Helicopter Rotor Measurement and data reduction of airloads and structural loads written by and published by . This book was released on 1968 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The report presents the results of a two-phase research program consisting of (1) in-flight measurement of aerodynamic pressures and structural loads on a compound, rigid-rotor helicopter and (2) correlation of these data with theoretical results. Flight test data obtained in Phase I and recorded on an oscillograph were read on an oscillograph reading machine and were processed in an automatic data reduction program. This data processing consisted of integration of the pressure data to obtain the distribution of aerodynamic lift and pitching moments over the rotor blade, as functions of azimuth position. Airload and structural load data were harmonically analyzed. Output of the data reduction program was used in Phase II as input to the correlation program. The measured airloads were used to compute the theoretical bending and torsion responses of the blade. The measured torsion moments were used in the theoretical prediction of the airloads. The results of the applied theories are compared with the flight measurements.
Download or read book Journal of the American Helicopter Society written by American Helicopter Society and published by . This book was released on 1999 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book In flight Measurement and Correlation with Theory of Blade Airloads and Responses on the Xh 51a Compound Helicopter Rotor written by E.A. Bartsch and published by . This book was released on 1968 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Correlation of Airloads on a Two Bladed Helicopter Rotor written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: Airloads measured on a two-bladed helicopter rotor in flight during the Ames' Tip Aerodynamic and Acoustic Test are compared with calculations from a comprehensive helicopter analysis (CAMRAD/JA), and the pressures compared with calculations from a full-potential rotor code (FPR). The flight-test results cover an advance ratio range of 0.19 to 0.38. The lowest-speed case is characterized by the presence of significant blade-vortex interactions. Good correlation of peak-to-peak vortex-induced loads and the corresponding pressures is obtained. Results of the correlation for this two-bladed rotor are substantially similar to those for three- and four-bladed rotors, including the tip-vortex core size for best correlation, calculation of the peak-to-peak loads on the retreating side, and calculation of vortex iduced loads on inboard radial stations. The higher-speed cases are characterized by the presence of transonic flow on the outboard sections of the blade. Comparison of calculated and measured airloads on the advancing side is not considered appropriate because the presence of shocks makes chordwise integration of the measured data difficult. However, good correlation of the corresponding pressures is obtained. Fernandez, Francisco J. and Johnson, Wayne Ames Research Center RTOP 505-59-36...
Download or read book In flight Measurement and Correlation with Theory of Blade Airloads and Responses on the XH 51A Compound Helicopter Rotor written by E. A. Bartsch and published by . This book was released on 1968 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book IN FLIGHT MEASUREMENT AND CORRELATION WITH THEORY OF BLADE AIRLOADS AND RESPONSES ON THE XH 51A COMPOUND HELICOPTER ROTOR VOLUME I MEASUREMENT AND DATA REDUCTION OF AIRLOADS AND STRUCTURAL LOADS written by and published by . This book was released on 1968 with total page 181 pages. Available in PDF, EPUB and Kindle. Book excerpt: The report presents the results of a two-phase research program consisting of (1) in-flight measurement of aerodynamic pressures and structural loads on a compound, rigid-rotor helicopter and (2) correlation of these data with theoretical results. Flight test data obtained in Phase I and recorded on an oscillograph were read on an oscillograph reading machine and were processed in an automatic data reduction program. This data processing consisted of integration of the pressure data to obtain the distribution of aerodynamic lift and pitching moments over the rotor blade, as functions of azimuth position. Airload and structural load data were harmonically analyzed. Output of the data reduction program was used in Phase II as input to the correlation program. The measured airloads were used to compute the theoretical bending and torsion responses of the blade. The measured torsion moments were used in the theoretical prediction of the airloads. The results of the applied theories are compared with the flight measurements.
Download or read book Qualitative Evaluation of Effect of Helicopter Rotor blade Tip Vortex on Blade Airloads written by James Scheiman and published by . This book was released on 1963 with total page 50 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book IN FLIGHT MEASUREMENT AND CORRELATION WITH THEORY OF BLADE AIRLOADS AND RESPONSES ON THE XH 51A COMPOUND HELICOPTER ROTOR VOLUME 3 THEORETICAL PREDICTION OF AIRLOADS AND STRUCTURAL LOADS AND CORRELATION WITH FLIGHT TEST MEASUREMENTS written by and published by . This book was released on 1968 with total page 141 pages. Available in PDF, EPUB and Kindle. Book excerpt: In most of the conditions analyzed, the computed bending moments were found to be in good agreement with the measured moments. The agreement between computed and measured torsion moments, however, was poor, indicating that improvements are required in the mathematical model as far as the torsional properties are concerned. (These may include the introduction of the control system degrees of freedom in the model.) Comparison of measurements with airloads obtained with the Cornell program shows good agreement of the variations of the airloads over the azimuth. At the lower forward speeds the rotor wake can be represented by a set of ring vortexes. An urgent need exists for a method for predicting wake deformation and for programming this method. Torsional responses are important in the computation of airloads. A rotor trim procedure included in a rotor loads program has been shown to be useful in the prediction of rotor loads. Based on the results obtained for chordwise bending moments, the relationship between normal force coefficient and chord force coefficient used in Lockheed Program I should be reexamined, particularly in high angle-of-attack areas. Such investigation may result in improved estimates of drag coefficients.
Download or read book IN FLIGHT MEASUREMENT AND CORRELATION WITH THEORY OF BLADE AIRLOADS AND RESPONSES ON THE XH 51A COMPOUND HELICOPTER ROTOR VOLUME 2 MEASUREMENT AND DATA REDUCTION OF AIRLOADS AND STRUCTURAL LOADS APPENDIXES 5 THROUGH 9 written by and published by . This book was released on 1968 with total page 455 pages. Available in PDF, EPUB and Kindle. Book excerpt: Contents: Differential pressure -- dynamic components; Differential pressure -- static components; Blade loads -- dynamic and static components; Harmonic components of airloads and pitching moments; Harmonic components of structural loads.
Download or read book Effects of Blade Stall on Helicopter Rotor Blade Bending and Torsional Loads written by S. V. LaForge and published by . This book was released on 1965 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt: The highest blade dynamic loads tend to occur under conditions of retreating blade stall. An investigation is made to compare measured and calculated blade bending loads under such conditions. The analysis is based on the use of normal modes and the numerical solution of the differential equations of motion (which eliminates the limitations caused by using harmonics of airloads). It also permits more accurate allowance for aerodynamic nonlinearities in the stalled region. The analysis also includes negative aerodynamic torsional damping when blade stall occurs, as well as the effects of blade bending and torsional deformations on airloads. Finally, the analysis includes an investigation of the effect of hysteresis of the lift coefficient/angle of at8tack relationship in stall. It is concluded that, in order to accurately calculate blade loads under conditions of retreating blade stall, the effects of lift hysteresis and negative aerodynamic torsional damping must be included, in addition to the usual nonlinearities in lift and moment coefficients. It is further concluded that a numerical integration of the differential equation (as opposed to a solution utilizing harmonics of airload) and inclusion of the effects of blade deformation are essential to achieve accurate definition of the airloads. (Author).
Download or read book In flight Measurement and Correlation with Theory of Blade Airloads and Responses on the XH 51A Compound Helicopter Rotor written by J. E. Sweers and published by . This book was released on 1968 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt:
