Download or read book Helicopter and V STOL Noise Generation and Suppression written by National Academy of Engineering. AERONAUTICS AND SPACE ENGINEERING BOARD. and published by . This book was released on 1968 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent discussions between scientists of the United States Army Research Office, Durham, North Carolina, and members and staff of the National Academy of Sciences and National Academy of Engineering have identified an urgent need for renewed effort toward suppression of helicopter and V/STOL noise in military operations. Use of the term VTOL is intended to apply to all aircraft capable of vertical flight, of which the helicopter is the best known example. Major recommendations were: (1) Criteria should be established for determining the benefits and costs of noise reduction, on a quantitative basis in both military and commercial operations. (2) Factors determining aural detectability should be established for acoustic signatures of type generated by VTOL aircraft. Annoyance factors should also be established. (3) Mechanisms of noise generation by rotors and propellers should be established by a basic research program including analytical studies and experimental investigations. (4) Standards should be established for measurement of noise levels and data reduction which could be applied on a consistent basis by all investigators using commercially available equipment.

Download or read book Helicopter and V STOL Noise Generation and Suppression written by and published by National Academies. This book was released on 1968 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Basic Mechanisms of Noise Generation by Helicopters V stol Aircraft and Ground Effect Machines written by M. V. Lowson and published by . This book was released on 1965 with total page 39 pages. Available in PDF, EPUB and Kindle. Book excerpt: The basic mechanisms of noise generation due to mass introduction, applied force and applied stress are discussed with reference to their implications for helicopters, V/STOL aircraft, and Ground Effect Machines. The significance of the dimensional dependence of monopole, dipole and quadrupole fields is shown. The results of a new theory giving the effects of system accelerations on noise are presented. This theory will often have application to noise problems for these machines because of the centrifugal accelerations associated with many of the noise generating components. System accelerations give rise to higher order poles in the sound field which become particularly important at high speeds. An expression for the sound field produced by fluctuating lift and drag forces in a rotating and convected system is given. As a further example of the application of the general theory the sound field radiated by a hovering helicopter is analyzed. It is shown how a previously unrecognized source of sound arises from the outward components of force induced by the effects of blade coning angle and lag. The source of sound has its maximum in the plane of the rotor disc. The importance of including the proper momentum terms in calculations of noise radiated by moving mass sources is demonstrated. (Author).

Download or read book U S Aeronautics and Space Activities written by United States. President and published by . This book was released on 1968 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book NASA EP written by United States. National Aeronautics and Space Administration and published by . This book was released on 1968 with total page 452 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Annual Report National Academy of Sciences written by National Academy of Sciences (U.S.) and published by . This book was released on 1969 with total page 444 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vols. for include reports for the National Research Council; 1965/66- include reports for the National Academy of Engineering; 1971/72- include reports for the Institute of Medicine.

Download or read book Aeronautics and Space Report of the President written by United States. President and published by . This book was released on with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book United States Aeronautics and Space Activities written by United States. President and published by . This book was released on with total page 662 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Reports and Documents written by United States. Congress and published by . This book was released on 1969 with total page 924 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 with total page 994 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Report of the National Academy of Sciences written by National Academy of Sciences (U.S.) and published by . This book was released on 1968 with total page 440 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book STAR written by and published by . This book was released on 1966 with total page 1230 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Aeronautics and Space Report of the President Activities written by United States. President and published by . This book was released on with total page 632 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Design Study of a Metropolitan Air Transit System MAT written by Stanford University. Department of Aeronautics and Astronautics and published by . This book was released on 1969 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book HELICOPTER AND V STOL AIRCRAFT NOISE MEASUREMENT PROBLEMS written by A-21 Aircraft Noise Measurement Aviation Emission Modeling and published by . This book was released on 2002 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Technical Abstract Bulletin written by and published by . This book was released on 1965 with total page 914 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Report of the National Academy of Sciences for the Year written by National Academy of Sciences (U.S.) and published by . This book was released on 1968 with total page 440 pages. Available in PDF, EPUB and Kindle. Book excerpt: