Talk:Sonic boom/Archive 1

Archive 1

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Question

Hey. When a plane travels at supersonic speed, does the sonic boom only happen ONCE, at the instant it breaks the sound barrier, or does the sonic boom happen at every point the plane is flying faster than the sound barrier? For example, if I fly from CA to NY, and break the sound barrier in Nevada, presumably people in Nevada will hear the boom. But, if I stay above the speed, will people in Utah, Nebraska, etc., also hear a sonic boom, or does it only happen that one time when I first break the sound barrier?

The sonic boom is a shock wave that travels away from the aircraft as long as it travels at supersonic speed. It's like the wake of a boat.Rsduhamel 20:51, 30 December 2005 (UTC)

any chance of a sound recording of a double boom?

No sound but a fantastic silent video from the US Navy. But which format is good ? I which suggest http://www.xvid.org. Any objections ?

Sounds good to me DooMDrat 12:41, Jan 31, 2005 (UTC)

Ericd 21:29 Apr 10, 2003 (UTC)

The photo is of a condensation cloud due to the Prandtl-Glauert Singularity and not of a sonic boom.

http://www.eng.vt.edu/fluids/msc/gallery/conden/pg_sing.htm

I wonder if all this should be moved to sound bareer ? Ericd 10:00 Apr 11, 2003 (UTC)

A similar photo is available as "press photo" (i.e. with permission to reproduce) at [1] and [2]. This photo is more than just the Prandtl-Glauert Singularity. The disturbance on the water seems to be the footprint of the sonic boom. 12.234.73.11 07:12, 15 Oct 2003 (UTC)

Sound barrier and sonic boom are two separate topics and should remain separate articles, with links to each other. Tempshill 17:40, 2 Dec 2003 (UTC)

Do SAM missiles create sonic booms?

Yes, anything going faster than the speed of sound does. However the power of the shock wave is a function of the size of the object and the lift it is generating, which in the case of a SAM is very small in both cases. In addtion the boom is in the form of a cone around the object, so if you imagine the SAM going up into the air, the chance that you would be in a position to hear it is pretty slim.

Any info regarding the use of Sonic boom as a weapon? I heard that during Vietnam War, fighter pilot flew supersonic at low altitude to use the boom to kill. Any truth?

I don't know about that, but I heard something a day or two ago about some soldiers (possibly Australian or British), in Iraq using a sonic boom to clear out a cement factory they wanted to capture. They wanted to capture the place without bloodshed or destruction, as it would be important to rebuilding the economy. That, and it was suspected to be holding munitions as well. The place was well guarded. So they got the Americans to send in a jet (possibly an F14) to do a low flyover of the cement factory at sufficient speed to cause a sonic boom. Within moments, the civvies were pouring out. They captured the place with little incident. That's all I remember. BTW, what's with that edit someone did a couple days back to remove that diagram? The one with the stick figure. DooMDrat 12:41, Jan 31, 2005 (UTC)

Article copies text verbatim from http://aerodyn.org/Acoustics/Sound/sound.html

FM-Value - units?

Which units of weight and length are used for the FM formula? If I use metric tons for weight and metres for length, I get roughly 0.3 for the Concorde (used 150 tons here, length = 61,66 m). lbs and ft, however, yield FM = 115.--SiriusB 13:40, 28 Apr 2005 (UTC)

Additional note: Could the formula be wrong? I get realistic values if the "exponent" 3/2 is taken es simple factor and weight in tons and length in metres: 150t/(3/2*62m)=1.61. A weight of 131 tons results in the FM value of 1.41. The formula used here is FM=W/(1.5*L)=2W/3L. For B-2707 (93.27 m, see [3]) we get FM between 1.39 (max. landing weight) and 2.18 (max. takeoff weight); for the Concorde (61.66 m) respectively 1.20 to 2.00.

The source for the wrong formula is most probably here. The formula is described as "proportional to the aircraft weight divided with the three-halves of the aircraft length". This is the modified version. The "original" formula displayed at the source site seems to be simply typed wrong. So I would expect that the corrected version is the correct formula.

Since the "original" formula is obviously wrong whereas the corrected one fits well, I boldly have replaced it in the article. Comments and further corrections are welcome.--SiriusB 11:26, 26 May 2005 (UTC)

Looks like you're right; but I'm still not absolutely 100% sure.

It's not a very trustworthy source since the text says 'proportional to', when it looks like it should be 'equal to', and the equation is wrong as well, so *both* text and equation seem erroneous in different ways.

It's also a bit strange that the FM has a correction factor in it, you'd have thought they could have just divided weight by length and be done with it. And the use of non metric unit of tonnes and meters... gah!

I googled for a better source, but nothing turned up.

Still, good work.

WolfKeeper

Merge proposal

See Talk:Sound_barrier

Contradiction?

"We experience the "boom" when there is a sudden rise in pressure, so the N-wave causes two booms, one when the initial pressure rise from the nose hits, and another when the tail passes and the pressure suddenly returns to normal."

Seems like a contradiction to me. Guinnog 20:23, 30 January 2006 (UTC)

Wording

"The later shock waves are somehow faster than the first one..." Can we improve. Rich Farmbrough 20:21 6 March 2006 (UTC).

Megawatt!?

From my limited physics education I find it difficult to believe that a sonic boom can deliver 167 MW (megawatts - 1,000,000 Watts) per square meter. Although I can believe it delivers mW (milliwatts - 1/1,000 Watt) per square meter. Is this just a bad prefix? I think sound pressures are typically given in dBmW (decibell milliwatts.) — Preceding unsigned comment added by Happy wanderer (talk • contribs) 13:50, 17 July 2006 (UTC)

Videos at the bottom

I find it very hard to believe that this: # F-14 Tomcat sonic boom flyby (with audio) (file info)

• F-14 Tomcat flies at Mach 1 over the water, creating a sonic boom as it passes.

is an accurate description of a sonic boom.

1) There IS no sonic boom in this video. 2) Just because the water below the aircraft is a whiteish hue it's caused by the altitude the F-14 is flying.. NOT a sonic boom it's unrelated phenomenon. 3) Those people in my mind would be very, very deaf if it really was a sonic boom that close to them. I kind of doubt they'd be cheering in jubilation. 4) I've seen this video on YouTube.. Same kind of dicussion ensues.

The shock would be generated around the aircraft, not on the water. not a sonic boom. 69.181.75.37 22:10, 22 November 2006 (UTC)

Match One?

The drawing says "Match One" can we fix it to say "Mach" one? M@$+@ Ju ~ ♠ 19:06, 19 March 2007 (UTC)

Image

Would this image be useful? 81.63.184.84 01:03, 19 April 2007 (UTC)

Sound file?

It would be nice to have a sound file. Could someone supply one pretty please? — Preceding unsigned comment added by 86.4.223.79 (talk) 23:02, 19 June 2007 (UTC)

Supersonic behind shock wave

Folks, I edited the article to remove the notion that the flow over a supersonic aircraft is subsonic behind the leading shock wave. While a bow shock (normal shock) does drop the gas behind it to subsonic (in the shock-fixed frame), an oblique shock does not (i.e. the gas is supersonic on both sides of the shock in the shock-fixed frame). Supersonic vehicles (as opposed to hypersonic vehicles) are designed to have a leading oblique shock, rather than a bow shock, and so the gas remains supersonic over the vehicle, outside of the boundary layer. The additional shocks produced by wings, tail, etc, are from the supersonic gas being turned to different angles, which requires additional oblique shocks. Blazotron 22:11, 25 June 2007 (UTC)

Units

Richard Seebass and his colleague Albert George at Cornell University 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 three-halves of the aircraft length, FM = W/(3/2·L) = 2W/3L. The lower this value, the less boom the aircraft generates, with figures of about 1 or lower being considered acceptable.

Umm, using which units? Dividing a weight by a length doesn't give a dimensionless constant. The 2/3 factor suggests calibration of desirable values against some kind of unit (so the bound can be placed at a nice round 1 rather than 1.5), so which one? -- Milo

Good question. In ever reference I have found to date, there are no dimensions given. Seebass has a recent paper on this that would likely solve the mystery, but it is only available for money. Maury 20:54, 1 May 2007 (UTC)

I tried to work out the correct units by taking the statistics of a Concorde and changing the units around until the result was 1.4, but then I noticed that the article doesn't state if the weight used should be the unfueled weight, the fueled weight or the maximum flying weight (which should be listed anyway) --Genejoker 08:45, 4 September 2007 (UTC)

WikiProject class rating

This article was automatically assessed because at least one WikiProject had rated the article as start, and the rating on other projects was brought up to start class. BetacommandBot 10:03, 10 November 2007 (UTC)

1991-1992 Sonic Boom in Western Washington

I remember during this time period, there was a really loud boom heard all over Western Washington. I cannot remember what the news media reported was the source, but does anyone have any leads? 209.91.38.50 00:54, 4 August 2007 (UTC)

A meteor? --Una Smith (talk) 21:17, 6 December 2007 (UTC)

Google

When finding this page from google it says "A sonic boom produced by an aircraft moving at twice the speed of sound." in the text. This seems to be very confusing as sonic booms occur when the aircraft passes the speed of sound. — Preceding unsigned comment added by Chiliap2 (talk • contribs) 21:28, 19 February 2008 (UTC)

Display format help, please

For some reason the Category area overlays the References area for this article. Assuming it's not a recently-introduced flaw in the default wikibook skin, I have no idea how to correct it. Perhaps somebody with a little more MediaWiki knowledge could handle this? --Joe Sewell (talk) 15:33, 6 June 2008 (UTC)

Mach Cutoff

The Sonic Boom entry, Abatement and Perceptions sections, merit some discussion of "Mach cutoff", an alleged phenomena occurring under certain high transonic speeds (~1.15 mach), altitudes, and atmospheric conditions, where no sonic boom reaches the ground. The FAA currently prohibits supersonic (>1.0 mach) flight over the United State by civilian aircraft due to the adverse effects of the sonic booms on population centers. At least one business jet developer is attempting to have the prohibition modified if the "Mach cutoff" effects can be reliably exploited. -- —Preceding unsigned comment added by Andy Perhach (talk • contribs) 22:56, 30 June 2008 (UTC)

Waqas

I would like to know what is the exact frequency of sonic boom? How much frequency can a normal human ear bare?

Any pulse of sound contains a range of frequencies, and an infinitesimally short one will produce "white noise", with a flat spectrum from 0 Hz to infinity Hz. Roughly, a pulse 1 ms long will have a top frequency of 1000 Hz about 3 octaves up from middle C, but remember the continuous range of freqencies below this. If you want to get technical, you might want to argue for a somewhat (1/6) lower frequency max, but we are talking principles here. I've heard a lot of sonic bangs and they sound a bit like heavy gunfire (no I haven't heard this first hand), a sort of crump, often double.

If you are young you will be able to hear from about 10 Hz to 20 kHz. Any or all of these at moderate powers are completely acceptable and harmless; it's high power that might do you damage, be unbearable. TSRL (talk) 22:35, 8 November 2008 (UTC)

Propellers?

The text currently reads: A sonic boom can also be heard on prop planes, even though they do not travel at the speed of sound. The high rotation speed of its rotors is usually faster than sound, creating the "beating, humming" noise of a prop plane.

This does not sound right to me, although my specialty is the history of aviation, not the physics of flight, so I am not quite confident enough to delete or edit it. It was my understanding that as propellers (or at least their tips) approach Mach 1, their aerodynamic performance is degraded considerably. The "beating, humming sound" of a piston-engined aircraft is a just a combination of engine noise and the propeller rotating--not a sonic boom. There are special supersonic propellers but these have never been mounted on any regular production airplane. 165.91.64.240 (talk) 13:46, 20 September 2008 (UTC)RKH

• • No doubt you are right. Take the Viscount 800 (yes, I know this is going back a bit but I have the data). The Dart 510, according to Jane's 1956-7 reached maximum revs or 14500 rpm. It was geared down by 1:0.093 so the prop ran at 1350 rpm or 22.5 rps. The prop diameter was 3.05 m, so the tip speed (how far in 1 sec) 3.05x pi x 22.5 = 215 m/s. That is about M 0.65 at sea level, which is roughly where you are when using max revs, at take off. The gearing ratio is chosen to keep the prop tip at a speed where compressibility effects are not too serious. So the more powerful the engine and hence the bigger the prop, the more rearing down one needs. Of course we have to add the speed of the aircraft (vectorily) to the tip speed on a fast aircraft, leading to interesting prop designs, such as those on the Airbus 400M. The beating effect, by the way is normally due to the props on a twin running at slightly different speed/frequencies; under these conditions you may hear the difference frequency and is nothing to do with compressibility. I think I'll take the comment out.TSRL (talk) 22:38, 8 November 2008 (UTC)

Used as weapon

I heard that during the Vietnam war, F-4 phantoms were flown supersonic close to ground to produce loud sonic booms to kill or seriously injure soldiers on the ground. Was it just a urban legend? Any retired pilot to confirm this? Kowloonese 22:43, 1 May 2006 (UTC)

Correct me if I'm wrong, but I say urban legend. A sonic boom would certainly harrass the enemy, but could an airplane generate a deadly sonic boom? I don't think so. Loss of hearing and psychological impacts are definitely possible though. 69.181.75.37 22:10, 22 November 2006 (UTC)

• There were reports of combat aircraft during Gulf War 2 using their sonic booms to give the entrenched enemy the impression that they were being bombed, causing them to flee their positions. But sonic booms as a killing weapon? I think urban legend. (Me thinks that the Vietnamese jungle would absorb much of the boom) -- Htra0497 (talk) 08:37, 16 January 2008 (UTC)

• • Don't forget that in the early days of supersonic fight, it was standard at airshows to generate a few booms at low altitude over the crowd, which never harmed any one. TSRL (talk) 22:58, 8 November 2008 (UTC)

merge

I think the two should merge because When a plane breaks the sound barrier, a sonic boom is the result

Felix1624 (talk) 20:33, 7 May 2008 (UTC)

Please be informed: a sonic boom is NOT resulted when the plane "breaks the sound barrier", it exists throughout the supersonic range.

I've not checked, but presumably the cone angle is that for M=2.0. TSRL (talk) 22:51, 8 November 2008 (UTC) I have checked now: the angle is 20 deg so M=2.92TSRL (talk) 21:29, 11 November 2008 (UTC)

Firearms

Firearms bullets do produce sonic booms, don't they? Bullets with higher velocities go faster than the speed of sound. Someone could mention this. -- 81.230.2.47 (talk) 21:36, 1 February 2008 (UTC)

• • They do, and there are many nice Schlieren photon displaying the density variation (qualitatively at least ) from the time of no less than Ernst Mach.TSRL (talk) 21:29, 11 November 2008 (UTC)

Sample

Can we get a sample? It's all well & good describing what it sounds like, but sample would be nice. 210.50.248.143 (talk) 12:40, 14 November 2008 (UTC)

• • It's there already. Go to "audible boom one or two" and run the Concorde piece. The aircraft is high enough for the "far field" N-type double shock, the classic sonic boom to be well developed. We are not told what frequency response their kit has, but it sounds plausible. Nearby, at low altitude things are messier, with shocks from all sorts of places where the local airspeed is high.TSRL (talk) 22:58, 14 November 2008 (UTC)

Drawings

Somebody please provide better drawings.

1. The red engine drawing is very unclear and confusing. Which end is at the front? It can be figured out, but why should the reader have to think about that? Objects usually move across a page from left to right, but this aircraft seems to be going from right to left. The two versions ("inefficient" and "unstable") appear to be making a comparison, but to what? Certainly not to each other because the engines are of a different design. Or, is the lower drawing an enlargement of the upper drawing? Where is the "spike" referenced in the caption? Maybe that pointy thing on the right? Okay, but how does it work? Overall, the drawing provides no information value. The caption contains the only useful information.

2. The next drawing (with "fuselage" and "area rule") makes no sense at all. What is it? Is there a wing there, as implied by the caption? Are we looking down or to the side? The "fuselage" looks more like a butterfly -- I fail to see an aircraft there. The captions says something about reusing some air displacement -- is the drawing trying to show this?

Jeff

• • Agree entirely. These pics appear on many web pages. The top one has something to do with shock waves and engine intakes, I think; nothing to do with sonic booms. The lower one, I guess connects to the "area rule". As you suggest, any meaning is deeply hidden and in any case a connection between area rule and booms would need making. I know they have been in the article since Sept 2005, but my view is they should go.TSRL (talk) 17:19, 17 November 2008 (UTC)

• • • Boom boom: they have gone! If the original inserters wish to bring them back, fine; but please explain and argue for their relevance. Enough folk (Jeff, Maury and so on have been unable to make sense of them, and this is supposed to be the easy intro article to compressible aerodynamics.TSRL (talk) 23:11, 17 November 2008 (UTC)

Sonic Laser

Does anyone know why this redirects here, there's no info on it here. 77.102.173.23 (talk) 18:50, 3 January 2009 (UTC)

Figure of Merit reloaded

Recently, somebody has reverted the FM to the most probably wrong power-law formula FM = W/L^3/2 without any comment. We already had this discussion and found that the formula is at least useless in its current form since no units of weight and length are given. Weight and length of the Concorde are 186 tons (metrical; maximum weight) and 61.66 metres. In SI units (kilograms and metres) we get FM = 186,000 kg / (61.66 m)^1.5 = 384 kg m^-3/2. With tons and metres it is FM = 0.384 t m^-3/2 and with lbs and feet FM = 143 lbs ft^-3/2. All these values are far from the value given in the article (1.4). For the empty weight (79 t) it is even worse. I therefore recommend to remove the formula entirely unless someone fixes it (maybe it is wrongly cited from the original source or it uses some arbitrary units).--SiriusB 08:45, 16 October 2007 (UTC)

FoM is proportional to W/L^3/2, not equal to it. I think you can find the formula here Seebass, R., and George, A. R., “Sonic Boom Minimization,” Proceedings, Second Sonic Boom Symposium, J. Acoustical Society of America, Vol. 51, No. 2 (Part 3), pp. 686-694, 1972. Ydorb (talk) 21:16, 14 March 2009 (UTC)

ThunderDrums

There is no sense in which sonic booms are like thunder, except that they are (like any another audible effect) the result of setting up a pressure wave, or wave group in air. Banging a drum produces a similar result (a bang) but by an entirely different mechanism. There is no fast moving object in thunder but the locally expanding air itself. Not helpful, it seems to me. TSRL (talk) 23:14, 8 November 2008 (UTC) A little reflection makes me think this comment is slightly (but only slightly) harsh. It may well be that the speed of sound in the hot, ionised air around the discharge is faster than in the surrounding atmosphere, in which case a shock wave will develop. Since the temperature is higher, so should the speed be. Seems quite likely, though I've not checked the details. Even so, IMHO it's not a helpful example for developing the idea of shock waves generated by a solid moving object in a gas, which we're trying to do here.TSRL (talk) 17:46, 11 November 2008 (UTC)

Agreed. A sonic boom is the sound pressure wave caused by the supersonic passage of an object. The crack of a high-powered rifle bullet flying overhead qualifies. Lightening, however, is a linear explosion resulting from superheated air, and is a distinctly different physical phenomenon. Verdict: reference removed. 23:02, 2 May 2010 (UTC) —Preceding unsigned comment added by 75.70.218.190 (talk)

Perception and Noise

Added the fact that nothing is heard from people in the airplane itself and that the boom is continuous. It is a common misconception that only one bang is heard on the plane and some even believe that only one place on the ground receives the boom. Preroll (talk) 04:37, 15 October 2010 (UTC)

question of sound dynamic

IF one could accelerate past the speed of sound, does the accelerated individual experience a sonic boom the instant the barrier is broken? And does sound cease beyond that point until the speed is reduced to subsonic?

This is in reference to the way some games like XGRA portray sonic booms, by breaking the sound barrier, you are met with a boom followed by silence, I'm just wondering if there's any truth to it. Murakumo-Elite (talk) 02:47, 18 June 2009 (UTC)

• • I believe this is now answered in "Perception and Noise".

Preroll (talk) 19:54, 23 October 2010 (UTC)

Suggestion for: Mach cone.svg

Regarding the diagram: Mach cone.svg. At mach 1, the mach cone exists, but it isn't shown in the image. At mach 1, the mach angle is pi/2, and the mach cone is actually a plane. Is it possible to add a red vertical line to the second image? See: http://img219.imageshack.us/img219/255/sonicfrontsqz7.jpg NOrbeck (talk) 10:01, 23 November 2010 (UTC)

International System of Units

It would be a good idea to use the International System of Units (meter, kilogram) instead of pounds and feet (which might still be put in brackets) — Preceding unsigned comment added by 82.231.224.218 (talk) 16:41, 20 June 2011 (UTC)

Can we rephrase this?

From Measurement and examples: "The pressure from sonic booms caused by aircraft often are a few pounds per square foot."

I do not know if it is just me but the wording seems a little off (not in the sense that the material is wrong, just that it doesn't seem to flow the most smoothly)... Ham Radio 01:59, 8 November 2011 (UTC) — Preceding unsigned comment added by Ke5skw (talk • contribs)

2012 Sonic Boom

This event has attracted coverage in the mainstream British media but is it really worthy of being mentioned in an encyclopedia? The only other specific event mentioned in the article is a notable series of tests which were carried out by the US government which have their own article. I'm going to see what others think but I have taken the liberty to remove some needless exposition about 'a surreal mystery' and something which appeared to insinuate some kind of conspiracy was at play (sigh). Thank you, PamukSoundystem (talk) 21:30, 12 April 2012 (UTC)

I took it out, Wikipedia is not about news, and sonic booms are far too common to mention here more than the very most important ones. This doesn't seem to have been a very major event at all, although sonic booms always seem very dramatic I'm sure.Teapeat (talk) 22:45, 12 April 2012 (UTC)

You're right. This is just a transient event which isn't of any long lasting significance. Thanks for sorting it out! PamukSoundystem (talk) 23:01, 12 April 2012 (UTC)

Wired use of the animated graphic

Just to note, Wired used the animated graphic in their article What Is the Speed of Sound? (with an image credit to Wikipedia, all below a link to this article. So that's nice ;) --Tagishsimon (talk) 20:16, 17 October 2012 (UTC)

Volcanos

The press is calling loud sounds from erupting volcanos "sonic booms". Search google for many examples. Is this is misnomer, or are there genuine faster-than-sound components of eruptions? Either way it should be mentioned. Zero^talk 02:33, 31 August 2014 (UTC)

Bullwhip? Still?

I was under the impression that the Bullwhip theory had been debunked as urban mythology, and that it was simply the violent reversal of the end of the whip creating a "step wave" in the air. Can somebody (re-)verify please. I find the cited article highly dubious as a source since the author is merely re-parotting opinions. If there is a link to actual experimental findings with results that would possibly convince me. 124.170.41.225 (talk) 22:59, 18 December 2013 (UTC)

It is a genuine sonic boom. See the reference I just added. Zero^talk 03:05, 31 August 2014 (UTC)

Actual phenom causing sound

The article limits the explanation of the exact SOUND phenomenon to this single phrase:

The "boom" is experienced when there is a sudden change in pressure...

There is more to this regarding what is actually being "heard". Can someone who has specific knowledge add to this? I take this explanation to mean that the sound phenomenon is the moving barrier (wave) between the normal and low pressure areas but I don't want to update the article based on this assumption. Or is it the sound of the normal pressure collapsing back into the low pressure area (like a clap)?

Since the article is about a sonic phenomenon it deserves a better explanation of what produces the sound. Arbalest Mike (talk) 14:35, 11 October 2014 (UTC)

Removed pistol shrimp

I removed the section referring to pistol shrimp. The cited reference merely says that the shrimp can be as loud as a Concorde, not that they actually produce a sonic boom like a Concorde does. I have not found any references that indicate that the shrimp's claw moves at supersonic speed, so it just produce a loud noise, not a sonic boom. Mnudelman (talk) 01:52, 13 October 2015 (UTC)

Good point. And anyway, by what means are the two sounds measured? Is it with a microphone right next to the shrimp in one case while in the other a microphone is on the ground as a Concorde passes overhead at 30,000 ft? Arbalest Mike (talk) 02:43, 14 October 2015 (UTC)

Audible boom one or two?

Here's a YouTube video that has one boom and two booms; why don't you always hear two booms? --Una Smith (talk) 19:22, 5 December 2007 (UTC)

There are two shock waves, one at the nose cone, the other at the tail. Kowloonese (talk) 00:21, 23 October 2008 (UTC)

You don't always here them if they're close together in time due to the way the human ear works; so they're nearly always double booms with long aircraft like Concorde, and single with short aircraft. It also depends a bit on how fast the aircraft is going because of the wake angle, but that's a smaller effect.- (User) Wolfkeeper (Talk) 01:03, 23 October 2008 (UTC)

In principle this is right but in practice wrong, in that small aircraft can readily produce double booms. In the 1950s in Eastern England both the RAF and USAF pilots were playing with their Hunters and Sabres etc. They produced a very well defined double boom, which made you jump the first time or two, but rapidly became the norm. We were also under the RAE Bedford to Wash high speed run for prototype Lightnings, F.D 2 etc. They were usually to high to recognise, a con-trail job but there were no Concordes nor Valkyries around then and there. B-36s, though they closed off the light a little did not go bang. Actually, one can do some numbers: a 10 m long aircraft travelling at say 300 m/s (the speed of sound not all that high up)will produce two shocks separated by 1/3 secs if the two shock waves are parallel. These will be heard as a double boom so long as the individual booms are over in, say 0.1 s. Memory (OK, distant) says it was perhaps more like 0.5 s, so maybe they were higher where M 1 is slower. One ought to have been able to work out their height ... TSRL (talk) 22:46, 8 November 2008 (UTC)

• • This calculation would not work well, since the two shocks in the far field (aircraft a long way away) are almost but not quite parallel. If the plane is nearby, then you may hear shocks from wing leading edges, canopy etc. Also note the shocks first form well below M=1, perhaps M=0.8 at the thickest (roughly) part of the wing as soon as the local air speed is M=1. This is on the top, low pressure wing surface. BTW, Dayton did a nice series of measurements with a SR71 plus F15 chase plane, fully instrumented, and also have published so excellent N wave pressure plots. I don't know if these are under copyright or not: careful use of one or two would help the article. The ground level shock from SR71 at M=1.5 at 48000 ft has a pulse separation of about 0.18 s. TSRL (talk) 17:19, 17 November 2008 (UTC)

• • Shocks form when the local flow exceeds the speed of sound, but this does not imply that a sonic boom results. Since the source of the shock is moving less than Mach 1, the energy dissipates in all directions rather than "piling up" in a sonic cone. 130.221.224.7 (talk) 21:02, 4 December 2015 (UTC)SS

Speed of shock wave

The article says, "Eventually they merge into a single shock wave, which travels at the speed of sound..." But if it's a shock wave, it's faster than the speed of sound, by definition. Am I right? Or not? — Preceding unsigned comment added by Yankeepapa13 (talk • contribs) 22:32, 7 August 2016 (UTC)

No, shock waves tend to propagate at the speed of sound in the medium they are travelling through. They propagate in the exact same way as sound waves, as they are a very similar phenomenon. However, it IS possible for a shockwave to move faster than the local speed of sound, but it consumes a lot of energy (which is lost to heat into the medium through which the wave is travelling) which must come from somewhere. An example is a shockwave from an explosion, which initially can move many times Mach1 as it is being propelled by the expansion of hot, high-pressure gas behind it - though it will rapidly slow down to Mach1. This is complicated by the fact that the *local* speed of sound under these conditions may be very different as the pressure/temperature/density environment will have diverged from atmospheric-normal. What you definitely CANT have, is a shockwave moving *slower* than the local speed of sound, as the pressure discontinuity would diffuse itself.178.15.151.163 (talk) 15:39, 11 August 2016 (UTC)

Good thing you didn't write the article. The article is bad enough .. what you wrote is TOTALLY confusing. I suppose you believe you know what you're saying. I suspect that few others do. 98.194.39.86 (talk) 11:04, 12 July 2017 (UTC)

Two Potential Sources

I'm a 4th-year college student working on my first wikipedia edits. I think that I've found two additional sources that could help this article. Both of these are only freely available as abstracts for conference talks, but I think that they may both be relevant to this article

Sonic Boom Human Perception Metrics (I've already added this one into the section discussing the need to create metrics for sonic booms)

https://aip.scitation.org/doi/abs/10.1063/1.4934481

Atmospheric Effects on the Propagation Direction of Sonic Booms

https://asa.scitation.org/doi/abs/10.1121/1.1912904

Would these be worth adding/keeping? — Preceding unsigned comment added by Manderso2234 (talk • contribs) 20:48, 8 April 2020 (UTC)

Sonic boom

The article says that a sonic boom is made in air,the pistol shrimp breaks the sound barrier in water. — Preceding unsigned comment added by Alhadialika (talk • contribs) 05:30, 2 March 2014 (UTC)

I'm struggling to find a reliable source either way, but in my understanding the pistol shrimp creates a cavitation bubble in the water similar to propeller blades under water. The collapse of that bubble is what then makes the loud sound. Manderso2234 (talk) 20:52, 8 April 2020 (UTC)

equation

According to the equation, if the source moves at the speed of sound, the denominator is equal to zero, implying the observed frequency is infinite. If the source moves at speeds greater than the speed of sound, the observed frequency is negative. — Preceding unsigned comment added by 2601:2C3:4201:D70:D948:2165:2686:D8E5 (talk) 20:30, 29 April 2020 (UTC)

Article "Bullet bow shockwave" redirected here

I have WP:BLANKANDREDIRECTed Bullet bow shockwave to this article. It had no citations and the topic appears to be a specific case of a sonic boom. cathartid - talk 18:25, 16 May 2020 (UTC)

Possible to hear the boom without hearing the airplane?

Mention if it is possible to hear a sonic boom without hearing any trace of an airplane. In other words the airplane is too far away to be hard, but the sonic boom still can be heard. Jidanni (talk) 04:25, 26 February 2021 (UTC)

Include practical distance examples

Give practical distance examples. For instance, a Sonic Boom occurs over Washington DC. Can it still be heard to people in Baltimore? Jidanni (talk) 04:27, 26 February 2021 (UTC)

Mention what sounds are often mistaken for Sonic booms

Mention what sound so often mistake for sonic booms when reporting to Environmental Protection authorities. Jidanni (talk) 05:20, 26 February 2021 (UTC)

Mention environmental monitoring

Mention if Environmental Protection authorities monitor all year long for Sonic booms? For instance your average citizen isn't going to have a tape recorder going all year long just to catch a once every two years sonic boom. Jidanni (talk) 05:21, 26 February 2021 (UTC)

Jurisdictions where it is still legal

Mention in what jurisdictions it is still legal to overfly populated areas creating sonic booms. For instance, some poorly governed third world country perhaps. Jidanni (talk) 05:24, 26 February 2021 (UTC)

Persons who have never heard a sonic boom

Mention if it is quite likely that that people born after 1973 have never actually heard a sonic boom in their lifetime, at least in the United States. Thus night not realize the implications. Jidanni (talk) 05:27, 26 February 2021 (UTC)

For instance they just might laugh it off as not a serious issue. Jidanni (talk) 05:30, 26 February 2021 (UTC)

Using internet,find out about sonic boom

Alaska 115.96.218.194 (talk) 07:33, 20 January 2022 (UTC)

Reference of sounds

There are several allusions to sounds with very large decibel ranges. The sounds referenced do not have anyhthing to reinforce the readers understanding of what that sound can be compared to. So information was added to further explain in depth. — Preceding unsigned comment added by Xavier402 assignment (talk • contribs) 18:38, 6 February 2022 (UTC)

Supersonic Aircraft

This text mentions supersonic aircraft on several occasions but does not clarify what a supersonic aircraft is nor what classifies it as such. I added a section and will add more later to help clarify for a reader who is unknowledgeable on the subject. — Preceding unsigned comment added by Xavier402 assignment (talk • contribs) 18:38, 6 February 2022 (UTC)

Bad References

Reference 3 goes to an FAA page not found message. Reference 4 redirects to what appears to be the homepage of a trade journal. Abqstever (talk) 05:39, 20 February 2022 (UTC)

Replace α with μ

It seems μ is the usual symbol for Mach angle so would anyone object to α being replaced with μ? Cheers, cmɢʟee⎆τaʟκ 11:27, 15 March 2022 (UTC)

The Endkjrbdj FX xb in cj

Gduezhhzhnf Dear nxjj — Preceding unsigned comment added by 92.11.219.105 (talk) 10:20, 21 May 2022 (UTC)

Medium other than air

This article seems to be exclusively concerned with sonic booms in air. Couldn't the same phenomenon also occur in other media (e.g. water)? I understand that since the speed of sound is faster in water it would be less likely to occur, but it might be worth mentioning, assuming there are reliable sources available. Grover cleveland (talk) 15:31, 12 August 2022 (UTC)