# Bomb pitch **URL:** \ **Category:** Factual Questions\ **Created:** [November 19, 2009, 2:27pm UTC](https://boards.straightdope.com/t/bomb-pitch/518144 "2009-11-19T14:27:16Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![mjk123](https://avatars.discourse-cdn.com/v4/letter/m/e0b2c6/32.png) [@mjk123](https://boards.straightdope.com/u/mjk123)\ **Post date:** [November 19, 2009, 2:27pm UTC](https://boards.straightdope.com/t/bomb-pitch/518144/1 "2009-11-19T14:27:16Z")
Why do bombs’ pitch change as they approach their target? You know that sound you always hear in the movies of bombs falling? Why the change in pitch as it drops? ---
**Author:** ![johnpost](https://avatars.discourse-cdn.com/v4/letter/j/f17d59/32.png) [@johnpost](https://boards.straightdope.com/u/johnpost)\ **Post date:** [November 19, 2009, 2:53pm UTC](https://boards.straightdope.com/t/bomb-pitch/518144/2 "2009-11-19T14:53:40Z")
drama and Doppler effect. ---
**Author:** ![Richard\_Pearse](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/richard_pearse/32/13144_2.png) [@Richard\_Pearse](https://boards.straightdope.com/u/Richard_Pearse)\ **Post date:** [November 19, 2009, 2:57pm UTC](https://boards.straightdope.com/t/bomb-pitch/518144/3 "2009-11-19T14:57:24Z")
WAG: The bomb is slowing down as it gets lower and enters thicker atmosphere. Edit: Hence the doppler effect. ---
**Author:** ![Philster](https://avatars.discourse-cdn.com/v4/letter/p/13edae/32.png) [@Philster](https://boards.straightdope.com/u/Philster)\ **Post date:** [November 19, 2009, 3:15pm UTC](https://boards.straightdope.com/t/bomb-pitch/518144/4 "2009-11-19T15:15:23Z")
Read up on doppler effect here: > **[Doppler effect](https://en.wikipedia.org/wiki/Doppler_effect)** > > The Doppler effect or Doppler shift (or simply Doppler, when in context) is the apparent change in frequency of a wave in relation to an observer moving relative to the wave source. It is named after the Austrian physicist Christian Doppler, who described the phenomenon in 1842. > A common example of Doppler shift is the change of pitch heard when a vehicle sounding a horn approaches and recedes from an observer. Compared to the emitted frequency, the received frequency is higher during the approa... The Doppler effect (or Doppler shift), named after Austrian physicist Christian Doppler who proposed it in 1842, is the change in frequency of a wave for an observer moving relative to the source of the wave (or vice versa). It is commonly heard when a vehicle sounding a siren or horn approaches, passes, and recedes from an observer. The received frequency is higher (compared to the emitted frequency) during the approach, it is identical at the instant of passing by, and it is lower during the recession. For waves that propagate in a medium, such as sound waves, the velocity of the observer and of the source are relative to the medium in which the waves are transmitted. The total **Doppler effect may therefore result from motion of the source, motion of the observer, or motion of the medium** etc ---
**Author:** ![c\_goat](https://avatars.discourse-cdn.com/v4/letter/c/f4b2a3/32.png) [@c\_goat](https://boards.straightdope.com/u/c_goat)\ **Post date:** [November 19, 2009, 7:29pm UTC](https://boards.straightdope.com/t/bomb-pitch/518144/5 "2009-11-19T19:29:33Z")
So is that sound the one heard by the bomber or the bombed? Would the other person hear an opposite sound? ---
**Author:** ![mlees](https://avatars.discourse-cdn.com/v4/letter/m/ba8739/32.png) [@mlees](https://boards.straightdope.com/u/mlees)\ **Post date:** [November 19, 2009, 7:41pm UTC](https://boards.straightdope.com/t/bomb-pitch/518144/6 "2009-11-19T19:41:07Z")
I dunno. I wouldn’t put too much faith in movies’ accuracy here. Remember, these are the same folks that show people getting blown across the room with a shotgun blast, too. Just a guess, but I am going to speculate anyway: Hollywood has trained us Americans to expect certain things in movies (cars can make long jumps and roar off without the undercarriage collapsing). Bomb whistles (and the siren in Stukas) have been historically attached to frighten the enemy, but I assume that by and large, approaching bombs in movies make the sound they do because they height tension and drama, and the audience has been trained to expect those noises. One of the things I recall in Vietnam documentaries was that high flying B52’s (who are so high you can’t hear them) were devasting because in one moment, there you are, marveling the butterflies, and the next moment, hell erupts all around you. ---
**Author:** ![Philster](https://avatars.discourse-cdn.com/v4/letter/p/13edae/32.png) [@Philster](https://boards.straightdope.com/u/Philster)\ **Post date:** [November 19, 2009, 8:24pm UTC](https://boards.straightdope.com/t/bomb-pitch/518144/7 "2009-11-19T20:24:14Z")
Some bombs have whistled. Most never did. This question was asked of some WWII vets on other boards and there was a consensus that some bombs whistled on the way down. At least one was equipped with a cardboard tube for the effect. They were all German-made. It is mostly dramatic effect from Hollywood, but we have an answer to the OP. The answer is still relevant if we concede the whistling/sound/siren was on bombers equipped with noise makers (often called sirens, and often the Stuka dive bomber is the plane). Whether the plane screams in and out during its dive and ascent or the bomb does on its dive, it’'s the Doppler Effect that needs to be appreciated. ---
**Author:** ![Malacandra](https://avatars.discourse-cdn.com/v4/letter/m/45deac/32.png) [@Malacandra](https://boards.straightdope.com/u/Malacandra)\ **Post date:** [November 19, 2009, 9:53pm UTC](https://boards.straightdope.com/t/bomb-pitch/518144/8 "2009-11-19T21:53:50Z")
[quote=“1920s Style “Death Ray”, post:3, topic:518144”] WAG: The bomb is slowing down as it gets lower and enters thicker atmosphere. Edit: Hence the doppler effect. [/QUOTE] Bit too wild I think. More likely you hear a descending shriek from one that’s missing you. The further away it gets as it drops, the more its velocity away from you increases, and hence the greater the Doppler down-shift. Whereas the one that gets you has a steadily increasing velocity towards you, and screams on a rising note. I half-remember this being explained (minus the physics) in _All Quiet on the Western Front_, but I may be wrong. ---
**Author:** ![mlees](https://avatars.discourse-cdn.com/v4/letter/m/ba8739/32.png) [@mlees](https://boards.straightdope.com/u/mlees)\ **Post date:** [November 19, 2009, 10:40pm UTC](https://boards.straightdope.com/t/bomb-pitch/518144/9 "2009-11-19T22:40:08Z")
> [@Philster](#): > > Some bombs have whistled. Most never did. This question was asked of some WWII vets on other boards and there was a consensus that some bombs whistled on the way down. At least one was equipped with a cardboard tube for the effect. They were all German-made. > > It is mostly dramatic effect from Hollywood, but we have an answer to the OP. > > The answer is still relevant if we concede the whistling/sound/siren was on bombers equipped with noise makers (often called sirens, and often the Stuka dive bomber is the plane). > > Whether the plane screams in and out during its dive and ascent or the bomb does on its dive, it’'s the Doppler Effect that needs to be appreciated. Sorry. You are correct. ---
**Author:** ![Super\_Kapowzler](https://avatars.discourse-cdn.com/v4/letter/s/a698b9/32.png) [@Super\_Kapowzler](https://boards.straightdope.com/u/Super_Kapowzler)\ **Post date:** [November 20, 2009, 12:03am UTC](https://boards.straightdope.com/t/bomb-pitch/518144/10 "2009-11-20T00:03:46Z")
Doppler effect and psy-ops. Some bombs were puposely-made to whistle. That’s why the Arc-Light missions were silent. Ancient people shot whistling-flaming-arrows, according to R. Lee Ermy on the show on TV. Fear is part of war. ---
**Author:** ![Jamicat](https://avatars.discourse-cdn.com/v4/letter/j/c67d28/32.png) [@Jamicat](https://boards.straightdope.com/u/Jamicat)\ **Post date:** [November 20, 2009, 1:29am UTC](https://boards.straightdope.com/t/bomb-pitch/518144/11 "2009-11-20T01:29:20Z")
Doppler works with bullets too…muhahaa. [http://video.google.com/videosearch?hl=en&safe=off&client=firefox-a&rls=org.mozilla:en-US:official&hs=PQd&q=shooting%20a%20steel%20target&um=1&ie=UTF-8&sa=N&tab=wv#hl=en&safe=off&client=firefox-a&rls=org.mozilla%3Aen-US%3Aofficial&hs=PQd&q=shooting+a+steel+target&um=1&ie=UTF-8&sa=N&tab=wv&qvid=shooting+a+steel+target&vid=6731590650052470927](http://video.google.com/videosearch?hl=en&safe=off&client=firefox-a&rls=org.mozilla:en-US:official&hs=PQd&q=shooting%20a%20steel%20target&um=1&ie=UTF-8&sa=N&tab=wv#hl=en&safe=off&client=firefox-a&rls=org.mozilla%3Aen-US%3Aofficial&hs=PQd&q=shooting+a+steel+target&um=1&ie=UTF-8&sa=N&tab=wv&qvid=shooting+a+steel+target&vid=6731590650052470927) ---
**Author:** ![Richard\_Pearse](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/richard_pearse/32/13144_2.png) [@Richard\_Pearse](https://boards.straightdope.com/u/Richard_Pearse)\ **Post date:** [November 20, 2009, 2:47am UTC](https://boards.straightdope.com/t/bomb-pitch/518144/12 "2009-11-20T02:47:50Z")
> [@Malacandra](#): > > Bit too wild I think. More likely you hear a descending shriek from one that’s missing you. The further away it gets as it drops, the more its velocity away from you increases, and hence the greater the Doppler down-shift. Whereas the one that gets you has a steadily increasing velocity towards you, and screams on a rising note. I half-remember this being explained (minus the physics) in _All Quiet on the Western Front_, but I may be wrong. There wouldn’t be any bombs accelerating away from you which is what would be required for the down shift. ---
**Author:** ![Uncertain](https://avatars.discourse-cdn.com/v4/letter/u/6a8cbe/32.png) [@Uncertain](https://boards.straightdope.com/u/Uncertain)\ **Post date:** [November 20, 2009, 3:10am UTC](https://boards.straightdope.com/t/bomb-pitch/518144/13 "2009-11-20T03:10:02Z")
Doesn’t the sound also drop in pitch as Wile E. Coyote plummets to the ground? Is that the same phenomenon? ---
**Author:** ![Umbriel2](https://avatars.discourse-cdn.com/v4/letter/u/4af34b/32.png) [@Umbriel2](https://boards.straightdope.com/u/Umbriel2)\ **Post date:** [November 21, 2009, 5:44am UTC](https://boards.straightdope.com/t/bomb-pitch/518144/14 "2009-11-21T05:44:08Z")
> [@Philster](#): > > The answer is still relevant if we concede the whistling/sound/siren was on bombers equipped with noise makers (often called sirens, and often the Stuka dive bomber is the plane). The Stuka’s siren [designed by WWI ace and Luftwaffe development chief Ernst Udet, was specifically called the “Jericho Trumpet”](http://www.avalanchepress.com/Stuka.php). ---
**Author:** ![Raguleader](https://avatars.discourse-cdn.com/v4/letter/r/258eb7/32.png) [@Raguleader](https://boards.straightdope.com/u/Raguleader)\ **Post date:** [November 21, 2009, 5:39pm UTC](https://boards.straightdope.com/t/bomb-pitch/518144/15 "2009-11-21T17:39:03Z")
I have read that the dive flaps on the Douglas SBD Dauntless dive bomber using by the US Navy in WWII were basically large flaps with air holes cut in them. One of the side-effects of this design was that if a squadron of Dauntlesses were descending upon you, the banshee-like wail would likely cause you to void your bowels. Also, it could distract a ship’s defenders from the far more vulnerable (and destructive) Torpedo bombers which would be attacking at the same time against a bigger target. Remember: Bombs make holes in the tops of ships to let the air in. Torpedos make holes in the bottom of ships to let the water in. I never did find out if this was an intentional design quality of the Dauntless, or just another fun feature that came about by chance. Oh, and fun fact: some “Smart” bombs (I think the older ones mostly) were known to make a “clicking” noise, due to the guidance fins snapping back and forth to guide the bomb in. More modern bombs had more finessed fins that did not need to snap all the way to the pegs in either direction to guide the bomb. ---
**Author:** ![Malacandra](https://avatars.discourse-cdn.com/v4/letter/m/45deac/32.png) [@Malacandra](https://boards.straightdope.com/u/Malacandra)\ **Post date:** [November 21, 2009, 8:57pm UTC](https://boards.straightdope.com/t/bomb-pitch/518144/16 "2009-11-21T20:57:22Z")
[quote=“1920s Style “Death Ray”, post:12, topic:518144”] There wouldn’t be any bombs accelerating away from you which is what would be required for the down shift. [/QUOTE] Suppose something passes overhead at a high speed. For simplicity’s sake, consider its movement as strictly horizontal. As it’s directly overhead, its velocity vector is normal to the line from you to it. Velocity away from you: nil. A few moments later, it’s a hundred yards downrange. Velocity away from you: considerable, and has been increasing since it passed overhead. There’s your acceleration away and your descending note. ---
**Author:** ![Richard\_Pearse](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/richard_pearse/32/13144_2.png) [@Richard\_Pearse](https://boards.straightdope.com/u/Richard_Pearse)\ **Post date:** [November 22, 2009, 1:02am UTC](https://boards.straightdope.com/t/bomb-pitch/518144/17 "2009-11-22T01:02:21Z")
> [@Malacandra](#): > > Suppose something passes overhead at a high speed. For simplicity’s sake, consider its movement as strictly horizontal. As it’s directly overhead, its velocity vector is normal to the line from you to it. Velocity away from you: nil. A few moments later, it’s a hundred yards downrange. Velocity away from you: considerable, and has been increasing since it passed overhead. There’s your acceleration away and your descending note. That would give it a brief descending note initially then the note would stabilise particularly as it accelerates toward the earth and it’s horizontal movement slows. That doesn’t fit with the classic noise which is a descending note until impact. Either bombs didn’t really sound like that, or if they did, that’s not a satisfactory explanation. ---
**Author:** ![Malacandra](https://avatars.discourse-cdn.com/v4/letter/m/45deac/32.png) [@Malacandra](https://boards.straightdope.com/u/Malacandra)\ **Post date:** [November 22, 2009, 8:53am UTC](https://boards.straightdope.com/t/bomb-pitch/518144/18 "2009-11-22T08:53:14Z")
Well, accelerating towards the earth doesn’t take anything away from horizontal movement, as I’m sure you know, but I’m sure as shooting not going to start number crunching at this point. Either bombs didn’t really sound like that, or if they did, it was a little gremlin playing a swannee whistle. Good enough for me. ---
**Author:** ![Richard\_Pearse](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/richard_pearse/32/13144_2.png) [@Richard\_Pearse](https://boards.straightdope.com/u/Richard_Pearse)\ **Post date:** [November 22, 2009, 9:38am UTC](https://boards.straightdope.com/t/bomb-pitch/518144/19 "2009-11-22T09:38:31Z")
No but air friction certainly slowed them down horizontally. ---
**Author:** ![yendis](https://avatars.discourse-cdn.com/v4/letter/y/ed8c4c/32.png) [@yendis](https://boards.straightdope.com/u/yendis)\ **Post date:** [November 22, 2009, 11:06am UTC](https://boards.straightdope.com/t/bomb-pitch/518144/20 "2009-11-22T11:06:15Z")
> [@Raguleader](#): > > I have read that the dive flaps on the Douglas SBD Dauntless dive bomber using by the US Navy in WWII were basically large flaps with air holes cut in them. One of the side-effects of this design was that if a squadron of Dauntlesses were descending upon you, the banshee-like wail would likely cause you to void your bowels. Also, it could distract a ship’s defenders from the far more vulnerable (and destructive) Torpedo bombers which would be attacking at the same time against a bigger target. > > Remember: Bombs make holes in the tops of ships to let the air in. Torpedos make holes in the bottom of ships to let the water in. > > I never did find out if this was an intentional design quality of the Dauntless, or just another fun feature that came about by chance. > > Oh, and fun fact: some “Smart” bombs (I think the older ones mostly) were known to make a “clicking” noise, due to the guidance fins snapping back and forth to guide the bomb in. More modern bombs had more finessed fins that did not need to snap all the way to the pegs in either direction to guide the bomb. The holes in the dive brakes were to prevent buffeting of the tail planes. The holes smoothed out the air flow but still allowed for a braking effect.