CHAS

 

Thanks for the reply. I understand and I guess you would have to have some random generating software to see on average how many rounds it would take with a CEP of 75 vs 230. Have you ever seen any fire tables (unclassifed) that might be able to provide me with an answer?

CHAS

 

Thanks for the reply. I understand and I guess you would have to have some random generating software to see on average how many rounds it would take with a CEP of 75 vs 230. Have you ever seen any fire tables (unclassifed) that might be able to provide me with an answer?

CHAS,

 

How about a more simpler question. What is the CEP of the 105mm at a low angle firing and a high angle firing. I found this for the 155mm "Desired Low angle CEP is 60 Meters. Threshold Low angle CEP is 120 Meters, Desired High Angle CEP is 150 meters, Threshold High Angle CEP is 275 meters. It is further specified that this must be attained at a range of 25,000 meters using a 2hour stale Meterological Message, and unconditiond charges and rounds.". Have you seen anything like this for the 105mm? 

If I can get a CEP reduction from 230m to 75m at the same range, how would that affect the number of rounds I might fire? For example, if I would fire a battery of 8 (105mm) at a target could I reduce the number of rounds to just 2? Any ideas?

Ah, this has been hashed over a coupla times - it depends on your objective (and not just destroy / neutralize / suppress) - a lesser amount of precise munitions might result in the same amount of materiel destroyed, but not have same suppressive effect on the enemy personnel, which can make a big difference.  Consider two scenarios - say, a COLT behind enemy lines trying to take out a truck-mobile SAM battery the night before an attack, and the objective of an infantry company assault the next day.  So in the case of the SAM battery, yes, it's all a game of probabilities and numbers, and a lower CEP should reduce the number of rounds needed to punch holes in the relatively flimsy missiles, radars, and commo equipment.  In the case of the infantry assault, I don't think you would want fewer rounds, even if they are more accurate, since the point of the artillery is to keep their heads down - actually hitting them is just a bonus.  Or think of it this way - a few precise rounds may take out an enemy machinegun, but a constant volume of fire could successfully suppress ALL of the enemy's machineguns, making for a much easier assault.

Um, doing some rough calculations (and *not* including anything that is classified) if all you care about is hitting the target and not suppressive effects, then going from 230 down to 75m CEP should allow you to use 1/10th as many rounds (but I probably made a mistake somewhere in my calculations)...

The first point is that CEP is a very poor measure of dispersion for artillery because PEline is very small and PErange is relatively large, CEP combines the two using RMS, the answer, frankly, is crap if you're looking for something approaching a reasonable model of the fall of shot.

 

Second point is that PEs in FTs apply to a single gun.  It's very rare that single guns are used.  That leads to the next point that guns don't normaslly all aim at the same point (they can, it's called 'converge').  Historically the guns in a battery have fired with lines of fire parrallel, but for the last 3 or do decades have fired with their aimpoints optimally distributed across the target area.  

 

The next point is the distribtion of the effects themselves.  Forget blast, it's mostly irrelevant.  Bomblets are distributed across an area, but not entirely evenly, and the area of their distribution depends on the HoB and angle of descent, the latter being a function of range and charge (so are PEs, and HoB means there is also a PEheight to worry about).

 

HE shells rely on fragments for their effect, depending on the shell design and the type of targets that were given to the designers as the important ones.  If men are your target then fragments will be very small, this means they have little of no effect against material, but there will be lots of fragments.  The direction of the main density of these fragments also depends on the angle of descent.

 

As you've probably worked out by now this is a complicated subject and I've barely scraped the surface.  There's more information on the 'Effects & Weight of Fire' page at  link

Thanks for the good information. So, if all this factors in, why would you want to digitize an artillery system like the 105mm? What benefit would you hope to gain? It appears it would only help in the setup and disperse times and only marginally help with the number of rounds to fire at a target.

Thanks, as you can tell I'm not an artillery guy:) Any other advantages?

It depends what you mean by digitization.

 

Using a computer to calculate firing data emerged in the 1960s and by the mid ot late 70s was pervasive in at least western amies, this was not 'computerisation' of manual methods and FTs, it used new mathematical models and new data.  There were several benefits, even with the first generation machines that had unbelievably little processing power by modern standards.  In no particular order I'd say the benefits were faster computation of more complex fire missions, eg Linear Smoke, particularly if you wanted to move its position (something no sane gunner attempted with manual calculations), improved accuracy in the calculations, the manual methods were riddled with simplified and approximate data, including the deduction of map data (bearing and distance from the map references), and fianlly avoidance of mistakes in calculations, which were almost always found before shooting (assuming proper procedures were used) but did waste time.  The next step in 'digitisation', again in the early 70s, was data transmission (instead of voice) of firing data from the CP doing the arithmetic to its guns.  This again was faster and removed another source of possible mistakes.

 

In parallel with this over the decades you have to thank 'digitization' for better quality meteor data (further improving the accuracy of fire).  Add laser range finders also from the mid 70s which improved target acquisition accuracy.  From the late 70s we got PADS which provided accurate fixation and orientation almost instantly (ie eliminated time consuming survey) to guns and target acquisition systems, although near instant accurate orientation had been introduced in the 60s with the first 'gyroscopic orienters'.

 

The adoption in the 90s of autonomous sights (ie providing self-orientation) has opened up a new tactical options.  Most notably widely dispersed gun positions with frequent movement (if faced by a serious CB threat) but also the ability to come into action very fast from the line of march (eg coming down from a quick action taking 5 - 10 mins by day) to 2 or 3 mins or less by day or night.  It's also speeded up normal deployments, but its the tactical benefits of fast and accurate quick actions that is having the real tactical impact on artillery employment.

 

The matter of calculating the amount of ammo to fire is a different issue altogether.   I think it remains true that some armies still think its nonsense, and prefer to rely on established norms and or an observer controlling fire to achieve the required effects.  As far as I know nobody has created a good mathematical model using realistically available data.  All that is available are models of varying degrees of sophistication and roughness of approximation.  The reality is that there are a lot of potential variables and getting good data for some of them is impractical - starting with the protective value of the terrain where the target is and how much damage/number of casualties are needed to achieve 'neutralisation'!  The best that can be said for the existing models is that they give an indication of the amount of ammo required, perhaps within 10% or so in ideal conditions.  This can useful at the tactical level, and possibly for wider planning purposes at the operational level.  The idea that you can calculate exactly how many rounds to fire to achieve a particular number of casualties is in pixy land.