This definition of indirect fire manages to miss most of the key points.
Indirect fire has to be used when a target cannot be seen through the gun's sights. It may be visible to the crew and it may be used even if the target is visible through the sights. Modern indirect fire emerged in theory in the 1880s and in practice in the 1890s when all necessary instruments became available. Indirect fire originally emerged to get gun positions out of direct fire from the enemy. Subsequently the primary purpose became to engage targets that were not visible from the proximity of the gun position.
Indirect fire involves setting firing data on the sights. This data involves something to give the azimuth to the target and something to give the range to the target. The former involves some sort of aiming point as a reference and the latter is usually converted to something relative to the horizontal plane. Modern practice is to take the target's grid reference or coordinates and calculate firing data between this and the gun's location, early indirect fire used other methods.
Indirect fire may be observed or predicted. Observed fire means a human observer or target acquisition system locates the target and can if necessary adjust the points of impact of the projectiles. The firing data for observed fire may or may not include corrections for non-standard conditions. In modern armies it usually does but this was not always the case.
Predicted fire means the target is accurately located by some means and firing data always includes corrections for non-standard conditions. The basic methods were developed and refined in World War 1. The objective of predicted fire is to avoid having to adjust the points of impact or to attack targets that cannot be observed due to their position, weather or darkness. Variations to standard conditions are caused by differences from standard air temperature, air pressure, wind speed and direction and the muzzle velocity of the gun (which has several sources including propellant temperature, projectile weight and the extent of barrel wear).
Nfe 02:54, 25 January 2007 (UTC)
Is this some sort of a joke to redirect the direct fire to indirect?! The two have almost nothing in common as forms of ordnance delivery other then using basic ballistics principles.--mrg3105 (comms) ♠♥♦♣ 02:36, 5 April 2008 (UTC) I take it back, this was not a joke...just written by someone not seemingly aware of military history and technology--mrg3105 (comms) ♠♥♦♣ 02:38, 5 April 2008 (UTC)
Is it correct to say that (technically) if a 45 degree shot (by elevation) reaches the longest distance, then a 30 degree (45-15) will reach the same distance as a 60 degree (45+15) shot? If so, could the lower-than-45 shot be considered direct fire, and the higher-than-45 shot considered indirect fire? If so, I think this is a great explanation (or one way of viewing things). —Preceding unsigned comment added by 220.127.116.11 (talk) 09:54, 22 July 2008 (UTC)
- No, it is not technically correct in atmospheric conditions to say a projectile fired at 30 degrees and one fired at 60 degrees travels the same distance. In fact, ONLY in a vacuum will the range of the projectile be at its greatest at 45 degrees. In atmospheric conditions, the range is at it's greatest somewhat below 45 degrees. This is because the trajectory curve is a non-rigid trajectory as a result of other forces besides gravity (wind resistance, etc.) and is not parabolic, but semiparabolic. See http://www.eugeneleeslover.com/USNAVY/CHAPTER-17-A.html
- As far as defining indirect fire as anything other than "non-line-of-site" I firmly disagree. In indirect fire, the guns are aimed off reference points that essentially mimic a compass, and the firing elevation data is based on calculating range-to-target. The guns don't see the target. An observer calls in the target location, the Fire Direction Center calculates the trajectory, the guns lay on said data, and fire the mission. Elevation of the guns is irrelevant. We already have terms for that (High Angle [above 45 degrees] and Low Angle [below 45 degrees]) This is why I disagree with Ft. Sill reecently deciding to (FA proponent, US Army and Marines) call "[Killer Junior]" Observed Indirect Fire. If the guns see the target and "direct lay" on it, it's not indirect anything. Caisson 06 (talk) 21:26, 10 July 2009 (UTC)
Somebody please explain the 45 degrees rule!
...an provide the graph. I couldn't even find a picture or diagram on Commons showing this. (Looked in Commons:category:Ballistics and Commons:category:Parabolas.) Here is one external link with the textbook image and a reference:
Prism paralleloscope for indirect fire?
What is this a Prism paralleloscope? This article is an orphan and not have any references or sources. And no other articles in Wikipedia does not mention such a device, including the article Indirect fire. Excuse my bad English. Andrew M. Vachin (talk) 13:33, 7 August 2013 (UTC)