Revolutionary Concepts for Helicopter Noise Reduction PDF Download
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Author: Bryan Edwards
Publisher:
ISBN:
Category : Helicopters
Languages : en
Pages :
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Book Description
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.
Author: Bryan Edwards
Publisher:
ISBN:
Category : Helicopters
Languages : en
Pages :
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Book Description
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.
Author: National Aeronautics and Space Adm Nasa
Publisher: Independently Published
ISBN: 9781723974304
Category : Science
Languages : en
Pages : 90
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Book Description
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
Author: Bryan Edwards
Publisher:
ISBN:
Category : Aerodynamic noise
Languages : en
Pages : 94
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Book Description
Author: Antonio Filippone
Publisher: Elsevier
ISBN: 0080461034
Category : Technology & Engineering
Languages : en
Pages : 594
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Book Description
Calculation and optimisation of flight performance is required to design or select new aircraft, efficiently operate existing aircraft, and upgrade aircraft. It provides critical data for aircraft certification, accident investigation, fleet management, flight regulations and safety. This book presents an unrivalled range of advanced flight performance models for both transport and military aircraft, including the unconventional ends of the envelopes. Topics covered include the numerical solution of supersonic acceleration, transient roll, optimal climb of propeller aircraft, propeller performance, long-range flight with en-route stop, fuel planning, zero-gravity flight in the atmosphere, VSTOL operations, ski jump from aircraft carrier, optimal flight paths at subsonic and supersonic speed, range-payload analysis of fixed- and rotary wing aircraft, performance of tandem helicopters, lower-bound noise estimation, sonic boom, and more.This book will be a valuable text for undergraduate and post-graduate level students of aerospace engineering. It will also be an essential reference and resource for practicing aircraft engineers, aircraft operations managers and organizations handling air traffic control, flight and flying regulations, standards, safety, environment, and the complex financial aspects of flying aircraft. - Unique coverage of fixed and rotary wing aircraft in a unified manner, including optimisation, emissions control and regulation. - Ideal for students, aeronautical engineering capstone projects, and for widespread professional reference in the aerospace industry. - Comprehensive coverage of computer-based solution of aerospace engineering problems; the critical analysis of performance data; and case studies from real world engineering experience. - Supported by end of chapter exercises
Author: Gordon J. Leishman
Publisher: Cambridge University Press
ISBN: 9780521858601
Category : Science
Languages : en
Pages : 860
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Book Description
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.
Author: Rajeev Kumar
Publisher: Springer Nature
ISBN: 9811605505
Category : Technology & Engineering
Languages : en
Pages : 1830
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Book Description
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.
Author: Abhilash Suryan
Publisher: Springer Nature
ISBN: 9811518920
Category : Technology & Engineering
Languages : en
Pages : 693
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Book Description
This book presents a collection of the best papers from the Seventh Asian Joint Workshop on Thermophysics and Fluid Science (AJWTF7 2018), which was held in Trivandrum, India, in November 2018. The papers highlight research outputs from India, China, Japan, Korea and Bangladesh, and many of them report on collaborative efforts by researchers from these countries. The topics covered include Aero-Acoustics, Aerodynamics, Aerospace Engineering, Bio-Fluidics, Combustion, Flow Measurement, Control and Instrumentation, Fluid Dynamics, Heat and Mass Transfer, Thermodynamics, Mixing and Chemically Reacting Flows, Multiphase Flows, Micro/Nano Flows, Noise/NOx/SOx Reduction, Propulsion, Transonic and Supersonic Flows, and Turbomachinery. The book is one of the first on the topic to gather contributions from some of the leading countries in Asia. Given its scope, it will benefit researchers and students working on research problems in the thermal and fluid sciences.
Author: Victor Fey
Publisher: Cambridge University Press
ISBN: 9780521826204
Category : Business & Economics
Languages : en
Pages : 258
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Book Description
This book describes a revolutionary methodology for enhancing technological innovation called TRIZ. The TRIZ methodolgy is increasingly being adopted by leading corporations around the world to enhance their competitive position. The authors explain how the TRIZ methodology harnesses creative principles extracted from thousands of successful patented inventions to help you find better, more innovative, solutions to your own design problems. Whether you're trying to make a better beer can, find a new way to package microchips or reduce the number of parts in a lawnmower engine, this book can help.
Author: David Alan Conner
Publisher:
ISBN:
Category : Acoustical engineering
Languages : en
Pages : 68
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Book Description
An experiment has been performed to investigate the reduction of high-speed impulsive noise for the UH-1H helicopter by using an advanced main rotor system. The advanced rotor system had a tapered blade planform compared with the rectangular planform of the standard rotor system. Models of both the advanced main rotor system and the UH-1H standard main rotor system were tested at 1/4 scale in the Langley 4- by 7-Meter Tunnel. In-plane acoustic measurements of the high-speed impulsive noise demonstrated that the advanced rotor system on the UH-1H helicopter reduced the high-speed impulsive noise by up to 20 dB, with a reduction in overall sound pressure level of up to 6 dB. (Author).
Author: F. H. Schmitz
Publisher:
ISBN:
Category :
Languages : en
Pages : 110
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Book Description
The theoretical and experimental status of helicopter impulsive noise is reviewed. The two major source mechanisms of helicopter impulsive noise are addressed: high-speed impulsive noise and blade-vortex interaction impulsive noise. A thorough physical explanation of both generating mechanisms is presented together with model and full-scale measurements of the phenomena. Current theoretical prediction methods are compared with experimental findings of isolated rotor tests. The noise generating mechanisms of high speed impulsive noise are fairly well understood - theory and experiment compare nicely over Mach number ranges typical of today's helicopters. For the case of blade-vortex interaction noise, understanding of noise generating mechanisms and theoretical comparison with experiment are less satisfactory. Several methods for improving theory-experiment are suggested.
