Download or read book Acoustical Effects of Blade Tip Shape Changes on a Full Scale Helicopter Rotor in a Wind Tunnel written by and published by . This book was released on 1978 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Acoustic Measurements of a Full scale Rotor with Four Tip Shapes Volume 1 Text Appendices A and B written by and published by . This book was released on 1984 with total page 96 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 1989 with total page 1134 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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.
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 Compressibility Effects on the Hovering Performance of a Two blade 10 foot diameter Helicopter Rotor Operating at Tip Mach Numbers Up to 0 98 written by Joesph W. Jewel and published by . This book was released on 1960 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Wind Tunnel Evaluation of a Model Helicopter Main Rotor Blade With Slotted Airfoils at the Tip written by and published by . This book was released on 2001 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt: Data for rotors using unconventional airfoils are of interest to permit an evaluation of this technology's capability to meet the U.S. Army's need for increased helicopter mission effectiveness and improved safety and survivability. Thus, an experimental investigation was conducted in the Langley Transonic Dynamics Tunnel (TDT) to evaluate the effect of using slotted airfoils in the rotor blade tip region (85 to 100 percent radius) on rotor aerodynamic performance and loads. Four rotor configurations were tested in forward flight at advance ratios from 0.15 to 0.45 and in hover in-ground effect. The hover tip Mach number was 0.627, which is representative of a design point of 4000-ft geometric altitude and a temperature of 95 degrees F. The baseline rotor configuration had a conventional single element airfoil in the tip region. A second rotor configuration had a forward-slotted airfoil with a -6 degrees slat, a third configuration had a forward-slotted airfoil with a -10 degrees slat, and a fourth configuration had an aft-slotted airfoil with a 3 degrees flap (trailing edge down). The results of this investigation indicate that the -6 degrees slat configuration offers some performance and loads benefits over the other three configurations.
Download or read book Acoustic Measurements from a Rotor Blade vortex Interaction Noise Experiment in the German Dutch Wind Tunnel DNW written by Ruth McVoy Martin and published by . This book was released on 1988 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt: Acoustic data are presented from a 40-percent-scale model of the four-bladed BO-105 helicopter main rotor, tested in a large aeroacoustic wind tunnel. Rotor blade-vortex interaction (BVI) noise data in the low-speed flight range were acquired using a traversing in-flow microphone array. The experimental apparatus, testing procedures, calibration results, and experimental objectives are fully described. A large representative set of averaged acoustic signals are presented.
Download or read book Effects of Compressibility on the Performance of Two Full scale Helicopter Rotors written by Paul J. Carpenter and published by . This book was released on 1951 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: An investigation has been conducted on the Langley helicopter test tower to determine experimentally the effects of compressibility on the performance and blade pitching moments of two full-scale helicopter rotors with twisted and untwisted blades over a tip-speed range from 350 to 770 feet per second.
Download or read book Helicopter Acoustics written by and published by . This book was released on 1978 with total page 416 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Helicopter Model Rotor blade Vortex Interaction Impulsive Noise Scalability and Parametric Variations written by and published by . This book was released on 1984 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: Acoustic data taken in the anechoic Deutsch-NIederlaendischer Windkanal (DNW) have documented the blade-vortex interaction (BVI) impulsive noise radiated from 1/7-scale model main rotor of the AH-1 series helicopter. Average model-scale data were compared with averaged full-scale, in-flight acoustic data under similar nondimensional test conditions. At low advance ratios (mu = 0.164-0.194), the data scale remarkably well in level and waveform shape, and also duplicate the directivity pattern of BVI impulsive noise. At moderate advance ratios (mu = 0.224-0.270), the scaling deteriorates, suggesting that the model-scale rotor is not adequately simulating the full-scale BVI noise; presently, no proved explanation of this discrepancy exists. Carefully performed parametric variations over a complete matrix of testing conditions have shown that all of the four governing nondimensional parameters -- tip Mach number at hover, advance ratio, local inflow ratio, and thrust coefficient -- are highly sensitive to BVI noise radiation. Keywords: Helicopter noise; Blade vortex interaction; Measured acoustics.
Download or read book Full Scale Wind tunnel Tests of Blowing Boundary layer Control Applied to a Helicopter Rotor written by John L. McCloud and published by . This book was released on 1960 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Wind tunnel Investigation of the Effects of Blade Tip Geometry on the Interaction of Torsional Loads and Performance for an Articulated Helicopter Rotor written by William T. Yeager and published by . This book was released on 1981 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book NASA Technical Note written by and published by . This book was released on 1971 with total page 464 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Devices that Alter the Tip Vortex of a Rotor written by and published by . This book was released on 2001 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt: Small devices were attached near the tip of a hovering rotor blade in order to alter the structure and trajectory of the trailing vortex. Stereo particle image velocimetry (PIV) images were used to quantify the wake behind the rotor blade during the first revolution. A procedure for analyzing the 3D-velocity field is presented that includes a method for accounting for vortex wander. The results show that a vortex generator can alter the trajectory of the trailing vortex and that a major change in the size and intensity of the trailing vortex can be achieved by introducing a high level of turbulence into the core of the vortex.
Download or read book A Wind tunnel Investigation of Helicopter Directional Control in Rearward Flight in Ground Effect written by Robert J. Huston and published by . This book was released on 1971 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: An investigation was conducted in the Langley full-scale tunnel to study the aerodynamics that produce directional-control problems for a helicopter with a tail rotor in low-speed rearward flight in ground effect. A helicopter model mounted close to the tunnel floor was tested in tail winds from 0 to 25 knots.
Download or read book Wind tunnel Measurements of Performance Blade Motions and Blade Air Loads for Tandem rotor Configurations with and Without Overlap written by Robert J. Huston and published by . This book was released on 1963 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt:
