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Book Investigation of Helicopter Control Loads Induced by Stall Flutter

Download or read book Investigation of Helicopter Control Loads Induced by Stall Flutter written by Peter J. Arcidiacono and published by . This book was released on 1970 with total page 179 pages. Available in PDF, EPUB and Kindle. Book excerpt: An analytical study was conducted to determine if available unsteady normal force and moment aerodynamic test data could be used in conjunction with existing helicopter rotor aeroelastic and variable inflow analyses to provide a method for predicting the stall flutter response of a helicopter rotor blade. For this purpose, incompressible unsteady aerodynamic data for an NACA 0012 airfoil executing pure sinusoidal pitching motions were employed. To apply such data under rotor blade operating conditions where multiharmonic motions and velocity variations exist, the data were expressed as functions of instantaneous section angle of attack, angular velocity, and angular acceleration. In addition, scaling procedures were developed in an attempt to account for the effects of compressibility. Limited application of the resulting analysis to define the aeroelastic characteristics of several blade designs showed that significant self-excited torsional oscillations of the stall flutter type could, in fact, be predicted for certain combinations of flight conditions and blade designs. Correlation studies, to evaluate the ability of the analysis to predict control loads, were performed with CH-53A maneuvering flight test data and with level flight test data from the NH-3A (S-61F). (Author).

Book Investigation of Helicopter Control Loads Induced by Stall Flutter

Download or read book Investigation of Helicopter Control Loads Induced by Stall Flutter written by P. J. Arcidiacono and published by . This book was released on 1970 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt: An analytical study was conducted to determine if available unsteady normal force and moment aerodynamic test data could be used in conjunction with existing helicopter rotor aeroelastic and variable inflow analyses to provide a method for predicting the stall flutter response of a helicopter rotor blade. For this purpose, incompressible unsteady aerodynamic data for an NACA 0012 airfoil executing pure sinusoidal pitching motions were employed. To apply such data under rotor blade operating conditions where multiharmonic motions and velocity variations exist, the data were expressed as functions of instantaneous section angle of attack, angular velocity, and angular acceleration. In addition, scaling procedures were developed in an attempt to account for the effects of compressibility. Limited application of the resulting analysis to define the aeroelastic characteristics of several blade designs showed that significant self-excited torsional oscillations of the stall flutter type could, in fact, be predicted for certain combinations of flight conditions and blade designs. Correlation studies, to evaluate the ability of the analysis to predict control loads, were performed with CH-53A maneuvering flight test data and with level flight test data from the NH-3A (S-61F). (Author).

Book NASA Technical Note

    Book Details:
  • Author :
  • Publisher :
  • Release : 1974
  • ISBN :
  • Pages : 482 pages

Download or read book NASA Technical Note written by and published by . This book was released on 1974 with total page 482 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Testing and Evaluation of a Stall flutter suppression System for Helicopter Rotors Using Individual blade control

Download or read book Testing and Evaluation of a Stall flutter suppression System for Helicopter Rotors Using Individual blade control written by Todd Randall Quackenbush and published by . This book was released on 1981 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Investigation of the Effect of Torsional Natural Frequency on Stall Induced Dynamic Loading

Download or read book Investigation of the Effect of Torsional Natural Frequency on Stall Induced Dynamic Loading written by F. J. Tarzanin and published by . This book was released on 1974 with total page 163 pages. Available in PDF, EPUB and Kindle. Book excerpt: For helicopter flight conditions at high blade loadings or airspeeds, the rotor control system experiences a rapid load growth resulting from stall-induced blade torsional moments. These loads frequently grow so large that the aircraft flight envelope is restricted. This report describes an analytical study that determined the effect of changing blade torsional properties on control loads for a wide range of flight conditions. (Modified author abstract).

Book NASA SP

    Book Details:
  • Author :
  • Publisher :
  • Release : 1991
  • ISBN :
  • Pages : 580 pages

Download or read book NASA SP written by and published by . This book was released on 1991 with total page 580 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Dynamic Stall of Small Wind Systems

Download or read book Dynamic Stall of Small Wind Systems written by Richard B. Noll and published by . This book was released on 1983 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Scientific and Technical Aerospace Reports

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 704 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Monthly Catalog of United States Government Publications  Cumulative Index

Download or read book Monthly Catalog of United States Government Publications Cumulative Index written by United States. Superintendent of Documents and published by . This book was released on 1976 with total page 1466 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Helicopter Theory

Download or read book Helicopter Theory written by Wayne Johnson and published by Courier Corporation. This book was released on 2012-03-07 with total page 1122 pages. Available in PDF, EPUB and Kindle. Book excerpt: Monumental engineering text covers vertical flight, forward flight, performance, mathematics of rotating systems, rotary wing dynamics and aerodynamics, aeroelasticity, stability and control, stall, noise, and more. 189 illustrations. 1980 edition.

Book Investigation of Airfoil Dynamic Stall and Its Influence on Helicopter Control Loads

Download or read book Investigation of Airfoil Dynamic Stall and Its Influence on Helicopter Control Loads written by Franklin O. Carta and published by . This book was released on 1972 with total page 187 pages. Available in PDF, EPUB and Kindle. Book excerpt: Measurements were made of the unsteady normal force and pitching moment on an NACA 0012 airfoil model oscillated both sinusoidally and nonsinusoidally over a range of incidence angles, including a substantial penetration into stall. The sinusoidal normal force and pitching moment data were reduced and tabulated as functions of the angle of attack, the angular velocity parameter, and the angular acceleration parameter. This generalized form of the data was used to reconstruct the measured sinusoidal aerodynamic response of the model airfoil with excellent results. Additional correlations were made using nonsinusoidal pitch schedules which included periodic ramp changes in angle of attack and a flexured angular blade response to a one-per-rev sinusoidal incidence angle change typical of that for a helicopter blade. The agreement between predicted and measured normal force and moment loops was very good for the ramp motion. (Author).

Book Rotorcraft Dynamics

Download or read book Rotorcraft Dynamics written by and published by . This book was released on 1974 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Principles of Helicopter Aerodynamics

Download or read book Principles of Helicopter Aerodynamics written by J. Gordon Leishman and published by Cambridge University Press. This book was released on 2002-12-23 with total page 544 pages. Available in PDF, EPUB and Kindle. Book excerpt: Helicopters are highly capable and useful rotating-wing aircraft with roles that encompass a variety of civilian and military applications. Their usefulness lies in their unique ability to take off and land vertically, to hover stationary relative to the ground, and to fly forward, backward, or sideways. These unique flying qualities, however, come at a high cost including complex aerodynamic problems, significant vibrations, high levels of noise, and relatively large power requirements compared to fixed-wing aircraft. This book, written by an internationally recognized expert, provides a thorough, modern treatment of the aerodynamic principles of helicopters and other rotating-wing vertical lift aircraft. Every chapter is extensively illustrated and concludes with a bibliography and homework problems. Advanced undergraduate and graduate students, practising engineers, and researchers will welcome this thorough and up-to-date text on rotating-wing aerodynamics.

Book Analysis of Helicopter Maneuver loads and Rotor loads Flight test Data

Download or read book Analysis of Helicopter Maneuver loads and Rotor loads Flight test Data written by Edward A. Beno and published by . This book was released on 1973 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt: A study was conducted in which available airload and blade response data for the NH-3A and CH-53A rotors were analyzed in an attempt to provide greater insight into the sources of rotor vibratory loads in both level and maneuvering flight. Primary emphasis in the study was placed on examining and understanding causes of high-frequency rotor control loads. Secondary objectives were: (1) to examine the effect of number of rotor blades on hub vibratory shear forces and (2) to assess which of the many terms appearing in the hub vibratory shear force expression were of most significance.