Talk:Sonic boom

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[edit] 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. ddd

[edit] Waqas

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

[edit] 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.

[edit] 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

[edit] 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)

[edit] 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.)

[edit] 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)

[edit] Street Fighter....

Guile's..... Sonic Boom.... Thats what I always think of when I hear sonic boom

You're not the only one, dude. SONIC BOOM! (83.151.131.116 23:10, 5 December 2006 (UTC))

[edit] Match One?

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

[edit] Image

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

[edit] 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)

[edit] Sound file?

It would be nice to have a sound file. Could someone supply one pretty please?

[edit] 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)

[edit] 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)

[edit] Figure of Merit reloaded

Recently, somebody has reverted the FM to the most probably wrong power-law formula FM = W/L3/2 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)

[edit] 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)

[edit] 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)

[edit] 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)

[edit] 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)