How quickly does penetration drop off at range?

[runequester]

Are there any easy formula or guideline for how quickly penetration drops off as range increases?

[Cross]

Here's an old post that may help:

Originally Posted by MarkSheppard

Okay let me take a stab at converting it into a form that works well on a forum:

Here's the numbers that I've found through testing.

5% percent of range = 100% Penetration
10% percent of range = 100% Penetration
15% percent of range = 100% Penetration
20% percent of range = 100% Penetration
25% percent of range = 82.5% Penetration
30% percent of range = 79.6% Penetration
35% percent of range = 75.8% Penetration
40% percent of range = 72.8% Penetration
45% percent of range = 71.2% Penetration
50% percent of range = 66% Penetration
55% percent of range = 62.8% Penetration
60% percent of range = 60% Penetration
65% percent of range = 55.6% Penetration
70% percent of range = 52.8% Penetration
75% percent of range = 49.8% Penetration
80% percent of range = 46% Penetration
85% percent of range = 42.6% Penetration
90% percent of range = 39.6% Penetration
95% percent of range = 35.4% Penetration
100% percent of range = 33% Penetration

So let us say we want to find the penetration of a weapon with say a 5 AP penetration and a range of 20, at say, 50% of it's range?

Firstly, we take the range (20) and multiply it by 50 to get the weapon's maximum range in meters, which is:

20 x 50 = 1,000 meters

50% of the weapon's maximum range is:

1,000 x 0.5 = 500 meters

Now we can figure out the penetration.

The penetration at 50% of the range is 66%; so

AP Penetration (5) x 0.66 = 3

So at 500 meters, the weapon will have a penetration power of 3.

Please note that this is the *AVERAGE* penetration; you'll find from time to time, your weapon will penetrate a little less or a little more, and a few times will massively overpenetrate or underpenetrate; I *think* the frequency of these occurences and how often they favor over or under penetration is linked to warhead size.

I *think* this is SPCAMO's way of simulating the effects of shell diameter vs armor thickness; the Soviet 122mm gun in WWII was very effective against German Heavy Armor because the shell diameter at 122mm was bigger than the armor thickness that was opposing it.

It's taken from this thread:

http://forum.shrapnelgames.com/showt...etration+table


cheers,
Cross

[Cross]

Mark made it clear that his formula was only an average, and my test results were certainly different.

The results I got included: max penetration only out to 10% range (instead of 20% range), and at max range I was only getting about 20 to 25% penetration (instead of 33% penetration).

I don't know what weapons Mark used to get his results, but it seems that results may vary quite widely depending on a number of factors; that may even include warhead size (Mark mentioned this) and crew experience.

I did a test that included accuracy (or caliber to barrel length ratio) and didn't find that made a difference.

I found that at close ranges the pen was more consistent, and at greater ranges you usually got one of two results. For example a gun may consistently pen 9 at 20% range, get 7s and 6s at 50% range, and at 60% range get 6s and 5s.
Then you get the occasional ‘wild card’ extra 1 or 2 pen; and you may also hit a ‘weak spot’ for an extra 1 pen.

My tests did show an approximate linear degrading of penetration from the range where you no longer get max penetration (10 to 20% range) to max range.

So theoretically, if you discover the range a weapon no longer achieves max pen, and the penetration a weapon achieves at max range, you should be able to come up with a formula to show approximate penetration at any range in between.

But that’s beyond my maths ability.


cheers,
Cross

[Cross]

OK, it appears I actually cracked the AP pentration code!

Once I realised the linear drop in penetration, I got my oldest son (who's a math whizz) to write me a formula where you enter the penetration at two different ranges and it will calculate the pentration at any other range.

Then I figured out the fractional role that warhead size plays, which was really the key to deciphering AP effectiveness. I remembered that SP design was influenced by tabletop wargaming, which I believe often used fractions.

Now I can instantly predict the base penetration of any weapon at any range, as long as I know the weapon's:

1. Max Pen
2. Max Range
3. Warhead size

I haven't tested it with sabot rounds yet, to see if any additional voodoo has been thrown into the pot, but I suspect that the extra penetration and differing ranges of sabots are enough, so I doubt there's more to them than that.

Then I'll try to make a penetration matrix or excel calculator that people may find useful.

cheers,
Cross