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people’s own homes computer-controlled loudspeaker boxes
that periodically play waveforms intended to sound like sonic
17
booms indoors . It is unclear if the results would have been
the same if the residents had been exposed to real superson- ic overflights. There have been a few recent studies of subjec- tive reaction to sonic booms heard indoors from overflights18, 19 but that research will not answer the questions we are seek- ing since low-boom sonic boom waveforms were not used.
In a few years it may be possible that indoor studies can be initiated using overflights of a real low-boom aircraft. The low amplitude N-wave flights at NASA Dryden have already been mentioned. Further, early in 2005 NASA announced that their Vehicle Systems Program was working on developing a low- boom flight demonstrator. However, changing priorities have delayed that initiative until some later time. If it is constructed, a low-boom demonstration aircraft would be very useful for testing the reactions of people in their own homes. Many researchers would then participate in in-home overflight stud- ies in conjunction with the FAA, NASA, and industry. That is the acid test. We all will really know then whether overland supersonic flight of civil aircraft will be acceptable.
Going further
Background literature on the topic of sonic booms is
20-22
available . An extensive list of references including sym-
posia and workshops on sonic boom is given in Reference 22. Additional references should soon be available, including the ISBF proceedings that have been published as part of the pro- ceedings for the 17th ISNA. That book should be available from the American Institute of Physics sometime in late 2006. AT
References and Further Reading
1. P. Henne, “Small supersonic civil aircraft,” Presentation at Aviation Noise and Air Quality Symposium, Palm Springs, CA, 27 February - 3 March, 2005
2. R. Lee and J.M. Downing, “Comparison of measured and pre- dicted lateral distribution of sonic boom overpressures from the United States Air Force sonic boom database,” J. Acoust. Soc. Am. 99(2) 768-776 (1996).
3. H. Carlson and F. McLean, “The sonic boom,” International Science and Technology No. 55, 70-80 (July, 1966).
4. Code of Federal Regulations, Title 14, Volume 2, Part 9 – General Operating and Flight Rules, Subpart I - Operating Noise Limits, Sec. 91.817, Civil aircraft sonic boom. Although now known as 14 CFR 91.817, even a few years ago this regu- lation was known as 14 CFR 91.55.
5. International Civil Aviation Organization (ICAO) Resolution A33-7: Consolidated statement of continuing ICAO policies and practices related to environmental protection, Appendix G — Supersonic aircraft — The problem of sonic boom. See www.icao.int.
6. S. Horinouchi, “Conceptual design for a low sonic boom SSBJ,” AIAA Paper 2005-1018, 43rd Aerospace Sciences Meeting, 10-
13 January 2005, Reno, NV.
7. Federal Register, 68(198) 59231-59232 (October 14, 2003).
8. As of this writing, the web site for these presentations is www.faa.gov/about/office_org/headquarters_offices/AEP/sup ersonic_noise/.
9. A. Seebass and A. George, “Design and operation of aircraft to minimize their sonic boom,” J. Aircraft 11(9) 509-517 (1974).
10. R. Mack and C. Darden, “Some effects of applying sonic boom minimization to supersonic cruise aircraft design,” J. Aircraft 17(3) 182-186 (1980).
11. L. Fisher, S. Liu, L. Maurice, and K. Shepherd, “Supersonic air- craft: balancing fast, affordable, and green,” Intl. J. Aeroacoustics 3(3) 181-197 (2004).
12. Bill Sweetman, “Whooshhh,” Popular Science 265(1) 56-62 (July 2004).
13. J.W. Pawlowsky, D.H. Graham, C.H. Boccadoro, P.G. Coen, and D. Maglieri, “Origins and overview of the shaped sonic boom demonstration program,” AIAA paper 2005-0005, 43rd AIAA Aerospace Science Meeting, 10-13 January 2005, Reno, NV. This was an introductory paper to a special session on SSBD/SSBE, and there were many other papers presented giv- ing additional detailed results.
14. V. Sparrow, “Sonic boom symposium: Forward,” J. Acoust. Soc. Am. 111(1, Pt. 2), 497 (2002).
15. See http://web.mit.edu/aeroastro/www/partner/.
16. J. Leatherwood, B. Sullivan, K. Shepherd, D. McCurdy, and S. Brown, “Summary of recent NASA studies of human response to sonic booms,” J. Acoust. Soc. Am. 111(1, Pt. 2), 586-598 (2002).
17. D. McCurdy, S. Brown, and R. Hilliard, “Subjective response of people to simulated sonic booms in their homes,” J. Acoust. Soc. Am. 116(3), 1573-1584 (2004).
18. P. Schomer, J. Sias, and D. Maglieri, “A comparative study of human response, indoors, to blast noise and sonic booms,” Noise Control Eng. J. 45(4) 169-182 (1997).
19. J. Fields, “Reactions of residents to long-term sonic boom noise environments,” NASA Contractor Rept. 201704, June 1997.
20. D. Maglieri and K. Plotkin, “Sonic boom,” Vol. 1, Chap. 10 in Aeroacoustics of Flight Vehicles: Theory and Practice, H. Hubbard, Ed., (NASA Langley Research Center, Hampton, VA, NASA Reference Pub. 1258, WRDC Technical Report, 90- 3052, 1991), pp. 519-561. Reprinted by Acoustical Society of America, Melville, NY.
21. K. Plotkin and D. Maglieri, “Sonic boom research: history and future,” AIAA Paper 2003-3575, Proc. of the 33rd AIAA Fluid Dynamics Conference, June 2003.
22. V. Sparrow, “Overview of sonic boom noise” in IMECE 2003, Proc. 2003 ASME Intl. Mechanical Engineering Congress and
26 Acoustics Today, January 2006