Download or read book Reduction of Blade Vortex Interaction Bvi Noise Through X Force Control written by National Aeronautics and Space Adm Nasa and published by Independently Published. This book was released on 2018-10-17 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: Momentum theory and the longitudinal force balance equations of a single rotor helicopter are used to develop simple expressions to describe tip-path-plane tilt and uniform inflow to the rotor. The uniform inflow is adjusted to represent the inflow at certain azimuthal locations where strong Blade-Vortex Interaction (BVI) is likely to occur. This theoretical model is then used to describe the flight conditions where BVI is likely to occur and to explore those flight variables that can be used to minimize BVI noise radiation. A new X-force control is introduced to help minimize BVI noise. Several methods of generating the X-force are presented that can be used to alter the inflow to the rotor and thus increasing the likelihood of avoiding BVI during approaches to a landing. Schmitz, Fredric H. Ames Research Center RTOP 505-59-36

Download or read book Reduction of Blade Vortex Interaction BVI Noise Through X force Control written by Fredric H. Schmitz and published by . This book was released on 1995 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Rotorcraft Blade vortex Interaction Noise Reduction Through Attitude and Flight Parameter Variations written by Juan Abelló and published by . This book was released on 2004 with total page 466 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Blade vortex Interaction Noise Generation and Directionality written by Wel-Chong Sim and published by . This book was released on 1996 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Machines Mechanism and Robotics written by Rajeev Kumar and published by Springer Nature. This book was released on 2021-07-21 with total page 1830 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume includes select papers presented during the 4th International and 19th National Conference on Machines and Mechanism (iNaCoMM 2019), held in Indian Institute of Technology, Mandi. It presents research on various aspects of design and analysis of machines and mechanisms by academic and industry researchers.

Download or read book Principles of Helicopter Aerodynamics with CD Extra written by Gordon J. Leishman and published by Cambridge University Press. This book was released on 2006-04-24 with total page 860 pages. Available in PDF, EPUB and Kindle. Book excerpt: Written by an internationally recognized teacher and researcher, this book provides a thorough, modern treatment of the aerodynamic principles of helicopters and other rotating-wing vertical lift aircraft such as tilt rotors and autogiros. The text begins with a unique technical history of helicopter flight, and then covers basic methods of rotor aerodynamic analysis, and related issues associated with the performance of the helicopter and its aerodynamic design. It goes on to cover more advanced topics in helicopter aerodynamics, including airfoil flows, unsteady aerodynamics, dynamic stall, and rotor wakes, and rotor-airframe aerodynamic interactions, with final chapters on autogiros and advanced methods of helicopter aerodynamic analysis. Extensively illustrated throughout, each chapter includes a set of homework problems. Advanced undergraduate and graduate students, practising engineers, and researchers will welcome this thoroughly revised and updated text on rotating-wing aerodynamics.

Download or read book Aerodynamic Aspects of Blade vortex Interaction BVI written by Chee Tung and published by . This book was released on 1996 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Blade Mounted Flap Control for BVI Noise Reduction Proof of Concept Test written by and published by . This book was released on 1995 with total page 198 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book International Aerospace Abstracts written by and published by . This book was released on 1999 with total page 974 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Revolutionary Concepts for Helicopter Noise Reduction SILENT Program written by Bryan Edwards and published by . This book was released on 2002 with total page 94 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Revolutionary Concepts for Helicopter Noise Reduction Silent Program written by National Aeronautics and Space Adm Nasa and published by Independently Published. This book was released on 2018-09-24 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt: As part of a NASA initiative to reduce helicopter main rotor noise, a Phase 1 study has been performed of candidate noise reduction concepts. Both conventional and novel design technologies have been analyzed that reduce the community impact of helicopter operations. In this study the noise reduction potential and design implications are assessed for conventional means of noise reduction, e.g., tip speed reduction, tip shapes and airfoil tailoring, and for two innovative design concepts: modulated blade spacing and x-force control. Main rotor designs that incorporate modulated blade spacing are shown to have reduced peak noise levels in most flight operations. X-force control alters the helicopter's force balance whereby the miss distance between main rotor blades and shed vortices can be controlled. This control provides a high potential to mitigate BVI noise radiation. Each concept is evaluated using best practice design and analysis methods, achieving the study's aim to significantly reduce noise with minimal performance degradation and no vibration increase. It is concluded that a SILENT main rotor design, incorporating the modulated blade spacing concept, offers significantly reduced noise levels and the potential of a breakthrough in how a helicopter's sound is perceived and judged. The SILENT rotor represents a definite advancement in the state-of-the-art and is selected as the design concept for demonstration in Phase 2. A Phase 2 Implementation Plan is developed for whirl cage and wind tunnel evaluations of a scaled model SILENT rotor.Edwards, Bryan and Cox, Charles and Booth, Earl R., Jr. (Technical Monitor)Langley Research CenterAIRCRAFT NOISE; NOISE REDUCTION; NASA PROGRAMS; ROTARY WING AIRCRAFT; AEROACOUSTICS; SOUND WAVES; WAVEFORMS; VORTICES; WIND TUNNELS; AIRFOILS; BLADE-VORTEX INTERACTION

Download or read book Blade mounted Trailing Edge Flap Control for BVI Noise Reduction written by A. A. Hassan and published by . This book was released on 1992 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Experimental and Computational Investigation of Tilt Rotor Hover Aeroacoustics written by David Rudolf Polak and published by Ann Arbor, Mich. : University Microfilms International. This book was released on 1996 with total page 634 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Journal of the American Helicopter Society written by American Helicopter Society and published by . This book was released on 2003 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effect of Wake Structure on Blade Vortex Interaction Phenomena Acoustic Prediction and Validation written by and published by . This book was released on 1995 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: During the Higher Harmonic Control Aeroacoustic Rotor Test, extensive measurements of the rotor aerodynamics, the far-field acoustics, the wake geometry and the blade motion for powered, descent, flight conditions were made. These measurements have been used to validate and improve the prediction of blade-vortex interaction (BVI) noise. The improvements made to the BVI modeling after the evaluation of the test data are discussed. The effects of these improvements on the acoustic-pressure predictions are shown. These improvements include re-structuring the wake, modifying the core size, incorporating the measured blade motion into the calculations and attempting to improve the dynamic blade response. A comparison of four different implementations of the Ffowcs Williams and Hawkings equation is presented. A common set of aerodynamic input has been used for this comparison. (AN).

Download or read book Investigation of the Orthogonal Blade Vortex Interaction written by and published by . This book was released on 2003 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: A Stereoscopic Particle Image Velocimetry (SPIV) system was developed and applied to measurements of the Orthogonal Blade-Vortex Interaction (BVI) in a wind tunnel. Measurements of the isolated vortex showed that the SPIV system could resolve the jet velocity profile within the vortex core to a reasonable accuracy, and views of the vortex from different sides of the wind tunnel showed similar velocity profiles. For the BVI measurements the SPIV system showed the existence of a strong.

Download or read book Aeromechanics Technology Product Design for the 21st Century written by and published by . This book was released on 1995 with total page 434 pages. Available in PDF, EPUB and Kindle. Book excerpt: