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Topic: Shaped Sonic Boom Demonstration

	Work Continues To Mitigate Bizjet Sonic Booms
		High speed without a sonic boom is a cherished goal of supersonic business jet designers, and four teams are working to further the technology under NASA contracts, with results to be reviewed early next year.
		The main focus of boom reduction efforts is to shape the pressure wave along the length of the aircraft so it won't coalesce into the standard sharp N-wave by the time it hits the ground.
		NASA's sonic boom mitigation project (SBMP) is the successor to SSBE and is the one whose plans to build a second demonstrator have been cut short.
	www.aviationweek.com /aw/generic/story_generic.jsp?channel=awst&id=news/11075p1.xml (1337 words)

	Sonic boom - Wikipedia, the free encyclopedia
		Sonic booms generate enormous amounts of sound energy, sounding much like an explosion; typically the shock front may approach 100 megawatts per square meter, and may exceed 200 decibels.
		In contrast to the (super)sonic boom of an aircraft, this "tunnel boom" is caused by a rapid change of subsonic flow (due to the sudden narrowing of the surrounding space) rather than by a shock wave.
		SSBD used a F-5 Freedom Fighter modified with a new body shape, and was tested over a two year period in what has become the most extensive study on the sonic boom to date.
	en.wikipedia.org /wiki/Sonic_boom (1653 words)

	Supersonic transport - Wikipedia, the free encyclopedia
		The SST was seen as particularly offensive due to its sonic boom and the potential for its engine exhaust to damage the ozone layer.
		The sonic boom was not thought to be a serious issue due to the high altitudes at which the planes flew, but experiments with the USAFs North American B-70 Valkyrie proved otherwise in the mid-1960s.
		During the original SST efforts in the 1960s it was suggested that careful shaping of the fuselage of the aircraft could cause the shock waves to interfere with each other, greatly reducing sonic boom.
	en.wikipedia.org /wiki/Supersonic_transport (2214 words)

	AWST STORY
		High speed without a sonic boom is a cherished goal of supersonic business jet designers, and four teams are working to further the technology under NASA contracts, with results to be reviewed early next year.
		The main focus of boom reduction efforts is to shape the pressure wave along the length of the aircraft so it won't coalesce into the standard sharp N-wave by the time it hits the ground.
		NASA's sonic boom mitigation project (SBMP) is the successor to SSBE and is the one whose plans to build a second demonstrator have been cut short.
	aviationnow.com /avnow/news/channel_awst_story.jsp?id=news/11075p1.xml (1299 words)

	Shaped Sonic Boom Demonstration - Wikipedia, the free encyclopedia
		This F-5E was modified by NASA for a constant area beyond drag optimum to reduce the sonic boom
		Shaped Sonic Boom Demonstration used a F-5 Freedom Fighter modified with a new body shape, and was tested over a two year period in what has become the most extensive study on the sonic boom to date.
		The demonstration was part of the Quiet Supersonic Platform program funded by DARPA.
	en.wikipedia.org /wiki/Shaped_Sonic_Boom_Demonstration (138 words)

	Sonic boom - One Language (Site not responding. Last check: 2007-10-26)
		The term is commonly used to refer to the air shocks caused by the supersonic flight of military aircraft or passenger transports such as the Concorde (Mach 2.2, no longer flying) and the Space Shuttle (Mach 27).
		Sonic booms generate enormous amounts of sound energy, sounding much like an explosion, typically the shock front may approach 100,000,000 watts per square meter, and may exceed 200 decibels.
		Richard Seebass and his colleague Albert George at Cornell studied the problem extensively, and eventually defined a "figure of merit", FM, to characterize the sonic boom levels of different aircraft.
	www.onelang.com /encyclopedia/index.php/Sonic_boom (1217 words)

	NASAexplores 9-12 Article: Lowering The Boom
		The sonic boom is an audible manifestation of shock waves generated at the nose of supersonic aircraft.
		The intensity of a sonic boom is influenced by several factors, including the size of the airplane, so planes large enough to carry many passengers would generate stronger shock waves.
		The sonic boom produced by the weaker pressure waves is quieter than a shock wave-generated sonic boom.
	www.nasaexplores.com /show2_912a.php?id=04-017 (797 words)

	Reference.com/Encyclopedia/Sonic boom
		A sonic boom can also be caused by high-speed trains in tunnels (e.g.
		In order to reduce the sonic boom effect on the opposite tunnel a special design of the tunnel exit is necessary.
		In contrast to the (super)sonic boom of an aircraft, this "tunnel boom" is caused by a rapid change of subsonic flow (due to the sudden narrowing of the surrounding space) rather than by a shock wave, and it has little effect to anything else than the train itself.
	www.reference.com /browse/wiki/Sonic_boom (1276 words)

	FLUG REVUE first flight gallery: Northrop Grumman F-5E SSBD
		The demonstrations are part of DARPA's Quiet Supersonic Platform (QSP) program, an ongoing effort to identify and mature technologies that could allow military and business aircraft to operate with reduced sonic boom.
		The noise heard on the ground as a sonic boom is the sudden onset and release of pressure after the buildup by the shock wave, also known as "peak overpressure."
		During the upcoming SSBD flight demonstrations, the modified F-5E will be flown through the supersonic corridor at the NASA Dryden Flight Research Center.
	www.flug-revue.rotor.com /FRTypen/FRERstfl/FR03Erst/PRF5SSBD.htm (610 words)

	NASA Vehicle Systems : Supersonic Aircraft (Site not responding. Last check: 2007-10-26)
		Their premise: Change an aircraft's shape, and you can change, and potentially reduce, the intensity of the sonic boom it produces.
		The SSBD program used a U.S. Navy F-5E modified with a specially shaped "nose glove," an aluminum substructure and a composite skin added to the underside of the fuselage.
		Demonstration flights of the F-5E on August 27, 2003 showed a reduction in intensity of the sonic boom produced by the modified fuselage at Mach 1.4.
	www.aeronautics.nasa.gov /vsp/SSBD.htm (275 words)

	ShowNews Online: NBAA 2005
		The agency's plan was to build a second manned low-boom demonstrator aircraft, and it wanted to issue a request for proposals as early as last September.
		SSBD was a culmination of the QSP program, which ended in late 2003.
		Shaping is important, but so is light weight, achieved through a combination of better lift-to-drag ratio, improved engine performance and advanced materials.
	www.aviationnow.com /shownews/05nbaa/pre01.htm (1406 words)

	NASA - Fixing What Yeager Broke: Reducing Sonic Booms
		Thunderlike sonic booms are cuased by the air molecules being crowded into shockwaves by an aircraft.
		The sonic boom is the "wake" of the plane's shockwaves combined together.
		In addition, sonic boom data was gathered on the ground by an array of 42 sensors and recording devices stretched out over two and a half miles under the flight path of the F-5E.
	www.nasa.gov /missions/research/sonic_booms.html (592 words)

	NOVA \| Supersonic Dream \| Shock Treatment \| PBS
		"The Shaped Sonic Boom Demonstrator was not intended to be a quiet plane, just quieter, to prove that we could change the shape of the boom and reduce the intensity, which we proved," says Ed Haering of NASA's Dryden Flight Research Center, who was principal investigator on the project.
		The result, he says, is a shaped sonic boom that is 20 to 25 decibels lower than the Concorde.
		The pressure change also generated a sonic boom, which is heard whenever a plane flies faster than the speed of sound.
	www.pbs.org /wgbh/nova/concorde/shock.html (1608 words)

	AeroWorldNet(tm) - Northrop Grumman Unveils Concept for Quiet Supersonic Aircraft [September 26, 2002]
		In addition, under a shaped sonic boom demonstration project of the QSP program, Northrop Grumman Integrated Systems has successfully completed a critical design review with DARPA, an important milestone in preparation for the first-ever flight demonstration of a sonic boom mitigated by airframe shaping.
		The sonic boom flight demonstration, which will occur at the NASA Dryden Flight Research Center at Edwards Air Force Base, Calif., will use a Northrop Grumman F-5E aircraft with a modified fuselage.
		The modified aircraft is expected to produce a specially "shaped" sonic boom with significantly less intensity than the conventional sonic boom produced minutes earlier by an unmodified F-5E.
	www.aeroworldnet.com /2nr092602.htm (391 words)

	Quiet Supersonic Platform (QSP) (Site not responding. Last check: 2007-10-26)
		The program is designed to motivate approaches to sonic boom reduction that bypass incremental "business as usual" approach and is focused on the validation of multiple new and innovative "breakthrough" technologies for noise reduction that can ultimately be integrated into an efficient quiet supersonic vehicle.
		It may be possible to meet DARPA's target for the sonic boom by changing the shape of the aircraft, and without using exotic technologies such as plasmas.
		The idea is not to eliminate the pressure wave but to change the normal 'N-wave' profile of the boom to a smooth hump, removing the rapid pressure rises at the nose and tail of the aircraft.
	www.globalsecurity.org /military/systems/aircraft/qsp.htm (981 words)

	Frank A. Roos
		sonic boom recordings from a SR-71 and a F16XL show, that in the recordings the double peaks of the SR-71 have a slightly larger separation than those of the F-16XL, indicating a greater length of the SR-71.
		Sonic booms can be recorded by seismological, acoustical or pressure sensor techniques.
		Currently at NASA research is underway to design aircraft with a small sonic boom signature, the Shaped Sonic Boom Demonstration (SSBD) project, which is part of the Defense Advanced Research Projects Agency's Quiet Supersonic Platform (QSP) program.
	homepages.cwi.nl /~faroos/index.shtml (480 words)

	NASAexplores 5-8 Article: Lowering The Boom
		The sonic boom is an audible result of shock waves created at the nose of supersonic aircraft.
		The sonic boom produced by the weaker pressure waves is quieter than a regular sonic boom.
		The volume of the sonic boom it generated as it flew at Mach 1.4 (or 1.4 times the speed of sound) was also measured.
	www.nasaexplores.com /show2_5_8a.php?id=04-017&gl=58 (788 words)

	Spaceflight Now \| Breaking News \| NASA opens new chapter in supersonic flight
		When the aircraft exceeds the speed of sound (approximately 750 mph at sea level), the pressure waves merge to form shock waves, which are heard as a sonic boom, when they reach the ground.
		NASA and industry sensors on the ground and in Dryden's F-15B measured the shape and magnitude of the sonic boom.
		Comparison of the data confirmed the modified shape of the test aircraft altered the sonic boom as expected.
	spaceflightnow.com /news/n0309/06supersonic (651 words)

	SPACE.com -- Shushing Sonic Booms: Changing the Shape of Supersonic Planes
		The trouble is that pesky sonic boom caused by breaking the sound barrier, rattling windows and -- if you're a military pilot -- alerting potential enemies of your presence during low flights.
		The added volume on the modified F-5E, however, allowed researchers to better distribute the air pressure build-up in front of a supersonic plane, which shapes how the pressure is later released in a sonic boom shockwave as the aircraft breaks the sound barrier.
		The Dryden-shaped sonic boom flights were confined to an existing airplane that had already undergone modifications to reduce boom noise.
	www.space.com /businesstechnology/technology/sonicboom_techwed_042104.html (800 words)

	Sonic boom - TheBestLinks.com - Concorde, DARPA, F-5 Freedom Fighter, Mach number, ...
		Sonic boom, Concorde, DARPA, F-5 Freedom Fighter, Mach number, Space Shuttle, 1...
		The term is commonly used to refer to the air shocks caused by the supersonic flight of military aircraft or (relatively rare) passenger transports such as the Concorde (Mach 2.2) and the Space Shuttle (Mach 27).
		Richard Seebass and his colleague Albert George at Cornell studied the problem extensively, and eventually defined a "figure of merit", FM, to characterize the sonic boom levels of different aircraft FM is proportional to the aircraft weight divided by the three-halves of the aircraft length, FM = W/L^(3/2).
	www.thebestlinks.com /Sonic_boom.html (1044 words)

	United Press International - Science(p) - Test shows shape sheds sonic boom's bang
		During a highly successful demonstration over the California desert, a modified fighter jet provided the first direct proof a change in an aircraft's shape mitigates the intensity of its sonic boom.
		The goal is to cut sonic boom noise by 75 percent.
		The idea behind shaping sonic booms is to spread out the pressure waves generated by the plane's high-speed disturbance of air across time, so when the waves hit the ground the resulting sound resonates for about 200 milliseconds, rather than about 50 milliseconds.
	www.upi.com /inc/view.php?StoryID=20030919-104035-3249r (1211 words)

	NASA - Supersonic Jousting
		Now, jet-borne jousting is combating supersonic shockwaves, hopefully enough to lessen the resulting sonic boom heard on the ground.
		While these tests won't actually 'quiet' the F-15's sonic boom, they will show that the spike's design is capable of use in a real flight environment.
		When an aircraft travels supersonically, the resulting shockwaves can produce a loud sonic boom that rattles windows and nerves on the ground under the path of the supersonic jet.
	www.nasa.gov /vision/earth/improvingflight/supersonic_jousting.html (576 words)

	Wyle Laboratories :: News Releases - Wyle Engineers Play Significant Role in Northrup Grumman Sonic Boom Test Program
		The objective of the Quiet Supersonic Platform was to develop advanced technology for low-boom supersonic aircraft while the objective of the Shaped Sonic Boom Demonstration project was flight verification that the shape of a sonic boom could be controlled by proper configuration of the aircraft.
		Propagation of sonic boom to the ground was calculated using PCBoom4, a program developed by Wyle.
		When the aircraft exceeds the speed of sound (approximately 750 mph at sea level), the pressure waves combine to form shock waves, which are heard as a sonic boom when they reach the ground.
	www.wylelabs.com /nr-03-13.html (695 words)

	Sonic boom: Facts and details from Encyclopedia Topic (Site not responding. Last check: 2007-10-26)
		A sonic boom is the audible component of a shock wave (A region of high pressure travelling through a gas at a high velocity)
		The sound of a sonic boom depends largely on the distance between the observer and the aircraft producing the sonic boom, Exception Handler: No article summary found.
		A sonic boom is usually heard as a deep double "boom" as the aircraft is usually some distance away, Exception Handler: No article summary found.
	www.absoluteastronomy.com /ref/sonic_boom (2169 words)

	CFD Review \| CFD Used In Sonic Boom Test Program
		Wyle was under contract to Northrop Grumman for the DARPA sponsored Quiet Supersonic Platform (QSP) and the Shaped Sonic Boom Demonstration (SSBD) project.
		In the Shaped Sonic Boom Demonstration project, Wyle provided engineering expertise in reduced sonic boom configuration analysis, and assisted Northrop Grumman in developing the shape of the modified Shaped Sonic Boom Demonstration platform.
		Wyle was also contracted by NASA to evaluate the effect of atmospheric conditions on the predicted sonic boom.
	www.cfdreview.com /application/03/09/23/1327257.shtml (718 words)

	NASA - Supersonic Baby Boom: NASA F-15B Chases the Modified Shock Wave of Altered Jet
		While this limits the impact of sonic booms on the population, it also inhibits the growth and utilization of high-speed flight.
		The objective of the SSBD project is to show that by modifying the shape of an aircraft, the shape and behavior of supersonic shock waves can be significantly altered, thereby reducing the intensity of sonic booms.
		Edward Haering, principal investigator for the SSBD project for NASA Dryden, is pleased to see this technology moving from the theoretical to the actual: "The ground-level sonic boom recordings we gathered with the modified and unmodified aircraft validates that the shaped sonic boom theory works with real aircraft through the real atmosphere."
	mynasa.nasa.gov /vision/earth/improvingflight/ssbd.html (655 words)

	BBC NEWS \| Science/Nature \| Supersonic planes may fly over towns
		During a highly successful demonstration over the Californian desert, a modified F-5E supersonic jet fighter provided proof that a change in an aircraft's shape mitigates the intensity of its sonic boom.
		The test showed that designing aircraft to a particular shape will keep pressure waves from merging, reducing the intensity of the sonic boom.
		Discussions to continue the Shaped Sonic Boom Demonstration programme are under way, said a representative with the Defense Advanced Research Projects Agency (Darpa), which manages the programme as part of its Quiet Supersonic Platform (QSP) initiative.
	news.bbc.co.uk /1/hi/sci/tech/3093720.stm (417 words)

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