Download or read book Measured Surface Pressure and Velocity Trends on a Highly Loaded Model Helicopter Rotor Experiencing Blade Slap written by James Edward Hubbard and published by . This book was released on 1981 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dynamic Pressure and Velocity Trends of a Model Helicopter Rotor Experiencing Blade Slap at High Angles of Attack and Low Tip Speeds written by James Edward Hubbard and published by . This book was released on 1981 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Vertica written by and published by . This book was released on 1985 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Rotating Hot wire Investigation of the Vortex Responsible for Blade vortex Interaction Noise written by and published by . This book was released on 1988 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Helicopter Blade Dynamic Loads Measured During Performance Testing of Two Scaled Rotors written by John D. Berry and published by . This book was released on 1987 with total page 54 pages. Available in PDF, EPUB and Kindle. Book excerpt: A test to determine the performance differences between the 27-percent-scale models of two rotors for the U.S. Army AH-64 helicopter was conducted in the Langley 14- by 22-Foot Subsonic Tunnel. One rotor, referred to as the baseline rotor, simulated the geometry and dynamic characteristics of the production baseline rotor, and the other rotor, referred to as the advanced rotor, was designed to have improved hover performance. During the performance test, the dynamic pitch-link forces and blade bending and torsion moments were also measured. Dynamic data from the forward flight investigation have been reduced and are presented herein. The advanced blade set was designed to have dynamic characteristics similar to those of the baseline rotor so that test conditions would not be limited by potential rotor instability and blade resonances and so that the measured performance increments could be considered to be due purely to aerodynamic causes. Data show consistent trends with advance ratio for both blade sets with generally higher oscillatory loads occurring for the advanced blade set when compared with the baseline blade set.

Download or read book Surface Pressure Measurements at Two Tips of a Model Helicopter Rotor in Hover written by Robin Bryant Gray and published by . This book was released on 1980 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Helicopter Rotor Rotational Noise Predictions Based on Measured High frequency Blade Loads written by Robert N. Hosier and published by . This book was released on 1974 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt: In tests conducted at the Langley helicopter rotor test facility, simultaneous measurements of up to 200 harmonics of the fluctuating aerodynamic blade surface pressures and far-field radiated noise were made on a full-scale nontranslating rotor system. After their characteristics were determined, the measured blade surface pressures were converted to loading coefficients and used in an existing theory to predict the far-field rotational noise. A comparison of the calculated and measured noise shows generally good agreement up to 300 to 600 Hz, depending on the discreteness of the loading spectrum. Specific attention is given to the effects of the blade loading coefficients, chordwise loading distributions, blade loading phases, and observer azimuthal position on the calculations.

Download or read book A Tabulation of Helicopter Rotor blade Differential Pressures Stresses and Motions as Measured in Flight written by James Scheiman and published by . This book was released on 1964 with total page 704 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Model Helicopter Rotor High speed Impulsive Noise Measured Acoustics and Blade Pressures written by and published by . This book was released on 1983 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Measurements of the Time averaged and Instantaneous Induced Velocities in the Wake of a Helicopter Rotor Hovering at High Tip Speeds written by Harry H. Heyson and published by . This book was released on 1960 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Comparison of Flight measured Helicopter Rotor blade Chordwise Pressure Distributions with Static Two dimensional Airfoil Characteristics written by James Scheiman and published by . This book was released on 1967 with total page 58 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book HELICOPTER BLADE SLAP written by F. Webb Taylor and published by . This book was released on 1966 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: The paper considers a possible mechanism for the generation of blade slap. A simplified theory for this is presented which shows good agreement with the results obtained from a test rig on which blade slap was simulated. In particular it show that the noise is dependent on the fourth power of the velocity and the square of the gust size (vortex strength). The results are sufficiently encouraging to warrant the extension of the analysis to that of an actual helicopter. Normally, blade element velocity in a helicopter can not be varied appreciably; it is fixed by far more important aerodynamic considerations. The profile of a vortex and its path are very important considerations that may possibly be partially controllable. Because the noise increases with the square of the vortex velocity amplitude (W), highly loaded rotor blades, which produce a strong tip vortex have a greater penchant toward loud blade slap. This contributes to the severity of the blade slap on the IROQUOIS which has a highly loaded two-bladed rotor. (Author).

Download or read book A Full Potential Flow Analysis with Realistic Wake Influence for Helicopter Rotor Airload Prediction written by T. Alan Egolf and published by . This book was released on 1987 with total page 104 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 Charts for Estimating Rotor blade Flapping Motion of High performance Helicopters written by Robert J. Tapscott and published by . This book was released on 1956 with total page 692 pages. Available in PDF, EPUB and Kindle. Book excerpt: Theoretically derived charts showing steady-state and first- and second-harmonic flapping coefficients are presented for helicopter rotors having hinged rectangular blades with a linear twist of 0, -8, and -16 degrees. The charts, showing the rotor flapping coefficients for combinations of inflow ratio and blade pitch angle, are presented for tip-speed ratios ranging from 0.05 to 0.50.

Download or read book Comparison of Calculated and Measured Helicopter Rotor Lateral Flapping Angles written by and published by . This book was released on 1980 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Unsteady Velocity Measurements Taken Behind a Model Helicopter Rotor Hub in Forward Flight written by and published by DIANE Publishing. This book was released on with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt: