Talk:Bombsight

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Mythic info[edit]

Removing the sentence "The Norden was considered one of the Allies' greatest technical secrets." for the simple reason that this just isnt true. It was once thought that it would or could be such, but experience showed it to have far less accuracy in reality as well as showing that high level bombing just wasnt accurate overall. In total, the Norden became a tiny technical footnote. Which is pretty much what the wikipage for the Norden says. In short, i dont believe todays wiki should use the perspective of 1941. DW75 (talk) 21:05, 4 May 2010 (UTC)[reply]

It's certainly true, but your comment is in reference to another aspect, its effectiveness. Whether effective or not, it was most carefully guarded. Precautions for its handling on the ground far exceeded those for H2S or IFF sets. Andy Dingley (talk) 09:38, 5 May 2010 (UTC)[reply]
No, my comment refers to the problem of writing "in character" in an encyclopedic structure. As written it makes it look as if this is also believed now. Or even that it was believed throughout the war, which it wasnt. You are taking an early war perspective and stating it as an overall fact.
If you refuse my edit then i suggest you do something yourself, keeping "in character" views in an article without clearly stating so is extremely bad practise.

DW75 (talk) 00:17, 23 May 2010 (UTC)[reply]

lohray: The First sentence refers to the last decade (from when?) 2011? Bomb sights were crosshair in 1990 - 2000?? —Preceding unsigned comment added by 75.110.213.245 (talk) 21:04, 23 May 2011 (UTC)[reply]

"Tachometric" bombsights[edit]

Please fix this. Tachometric is not the same thing as tachymetric. Andy Dingley (talk) 22:05, 23 October 2011 (UTC)[reply]

From an article here on the wiki:"The term tachymetric should more properly be spelled as "tachometric" which comes from the Greek "takhos" = speed, and "metric" = measure, hence tachometric, to measure speed." In the 1930s, when these devices were being designed and built, the use of the "o" form as distinct from the "e" or "y" form had not yet become common due to the automotive use in RPM gauges. For instance, this book clearly talks about the introduction of the new Lofte 7 tachometric bombsight into German service. This is hardly unique; this source is from the US, while this one is from the UK. That's not to say "tachymetric" isn't seen either, but it appears to be rare and I have not found it used in any contemporary resource. Maury Markowitz (talk) 11:32, 31 October 2011 (UTC)[reply]
WP is not WP:RS Do you really have to be told this? Specifically the Greek translation is wrong in that article. "tachy-" doesn't mean "speed" here, but rather "speedy" i.e. not a measure of speed, but a measure (of anything) that is performed quickly.
The Norden bombardier's manual itself uses tachymetric. Tacho- is commonly used in relation to measuring rotational speeds, tachy- in relation to distance (surveyor's tachymeters etc.). The point of a tachymetric bombsight is not that it measured rotational speeds, but that it used inputs of ground speed and altitude (and in later cases, gyroscopic inputs for orientation too) to move a virtual aim point across the ground at a tachymetrically-compensated velocity, thus simply requiring the bombardier to place this aim point onto the target once, not to have to "aim off" for a predicted track manually. Andy Dingley (talk) 12:21, 31 October 2011 (UTC)[reply]
References please. References of this calibre, or this, this, this and this. As you can see, these references (among the thousands google immediately returns) clearly demonstrate the "o" form of the word is widely used, in contemporary wartime sources as well as modern ones, both officially and academically. So if you wish to have the spelling changed, as you argue here, simply providing a single source will not be enough. You will need to provide enough quality references that show that the "y" form was in widespread use at the time, and those sources will also have to state why the widely-used "o" form is in error. As before, until references are provided I will not consider augmentative responses like this one worthy of further effort on my part. Thanks! Maury Markowitz (talk) 15:25, 31 October 2011 (UTC)[reply]

References:

Should ref. 9 be spelled "ordnance"?

Should "The Legendary Norden Bombsight", by Albert L. Pardini, Atglen, PA, Schiffer Military History, 1999, be included?

Rosswhis (talk) 19:58, 27 August 2012 (UTC)[reply]

Tables? Terminal Velocity?[edit]

  "Assuming errors of 5% in every major measurement, one can estimate those effects on accuracy based on the methodology and tables in the guide. A 5% error in altitude at 20,000 feet would be 1,000 feet, so the aircraft might be anywhere from 19 to 21,000 feet. According to the table, this would result in an error around 10 to 15 feet. A 5% error in airspeed, 10 mph, would cause an error of about 15 to 20 feet. In terms of drop timing, errors on the order of one-tenth of a second might be considered the best possible. In this case the error is simply the ground speed of the aircraft over this time, or about 30 feet. All of these are well within the lethal radius of the bomb."

What guide? What tables? This sounds like something that was copied directly from another source. Even if referring to the previously mentioned "Terminal Ballistic Data, Volume 1: Bombing", we shouldn't be referencing tables that aren't included in the article. I doubt most people own a copy of aforesaid book, nor would it be obvious which table in the book it is referencing. 

  "If the bomb is released at low speeds, it will quickly turn vertical and the velocity will be defined largely by how long the bomb has been falling. However, if it is released at high speed, it may already be close to terminal velocity and can only accelerate vertically after bleeding off some of its horizontal speed. Reaching terminal velocity tends to flatten the trajectory, keeping the bomb in the air longer, and thereby allowing the horizontal speed to act over a longer time, extending the range."

Sorry, but I don't understand this: it seems to suggest that the bomb will not begin to fall until it has slowed down some. It's my understanding that an object put into freefall will immediately begin to accelerate at a constant, and precise, rate until reaches terminal velocity, regardless of its forward motion. I'm assuming I'm misreading something, but I can't figure out what. What other meaning can "vertical acceleration" have? AnnaGoFast (talk) 23:30, 6 May 2016 (UTC)[reply]

"Terminal velocity" is the velocity of the bomb, under a force equivalent to 1g acceleration, when the aerodynamic drag of the bomb equals that force (and so it won't then accelerate any further).
If the bomb is a spherical cannonball, its vertical terminal velocity will be the same, no matter what its forward velocity. If it has some forward velocity as well, then its total velocity (the vector sum of both parts) can exceed the normal (no forward velocity) vertical speed.
If the bomb is more typical though, its terminal velocity is strongly dependent on its orientation. A vertically-falling bomb will orient itself to fall nose-down and will achieve its maximum velocity downwards. A bomb falling forwards though will orient itself in the direction of travel and so it has greater drag vertically, thus is incapable of reaching the same terminal speed vertically. If designed carefully to do so (a long thin bomb dropped at the right speed), this could significantly reduce its total velocity, compared with vertical dropping - this technique was used to increase bomber escape time from some smaller nukes (others used parachutes or laydown). Andy Dingley (talk) 00:40, 7 May 2016 (UTC)[reply]

External links modified[edit]

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Unmentioned force?[edit]

I am certainly no physicist, but it seems to me that for the average person, at least a mention of forward momentum of the released bomb would be helpful.In an episode of Hogan's Heros, Hogan refused to let Carter drop his bombs from a stolen German plane until they were directly above the target. Might be a surprise to Galileo and Newton, but most folks likely see bombing as done in this manner. — Preceding unsigned comment added by 108.249.146.8 (talk) 00:37, 8 June 2019 (UTC)[reply]

"Now consider the horizontal motion. At the instant it leaves the shackles, the bomb carries the forward speed of the aircraft with it." - added momentum. Maury Markowitz (talk) 21:54, 16 May 2021 (UTC)[reply]

Accurary example, AN-M65 or AN-M64?[edit]

@Maury Markowitz: the accurary example given is for AN-M65 500 lbs General-Purpose Bomb, but AN-M65 is a 1000 lbs bomb. The reference Bombing, page 10 is for AN-M64, which is indeed a 500 lbs bomb. Do you remember which bomb you were using as the example? MKFI (talk) 17:35, 16 May 2021 (UTC)[reply]

@MKFI: Well spotted - fixed! Maury Markowitz (talk) 14:13, 21 May 2021 (UTC)[reply]
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