Which tank gun range?

[Last Hussar]

I'm doing vehicle add on for the Infantry game.  Scale is 1:200, so it fits with 10mm ish figs - WYSIWYG.

I've Worked out the system, but the stats I am using are for the 800m range band.  Calculated Penetration in most cases drops by 10-15% between the bands
100m - 200m - 400m - 800m

eg for 95mm QF - Penetration(mm@30°)   142   135   125   113   

Is it worth using the 100 or 200m penetrations, or assume because these are mathematical models that actual performance at 100m (50cm on table) could reasonably be expected to be that sort of real world performance?   

[Orcs]

Go the same way as BKC and give a bonus for under half range.  There ae so many issues beyond theoretical penetration out would spend all evening working out a single firing scenario.

eg
To hit:-

Quality of Gun Optics (German sights were far better than anyone elses)
Gun stability
Speed of both firer and target
Training of gunner (ie did he aim for weak spots


Once hit

Type of armour (Late war german stuf was brittle)
Angle of the part actually hit.-
Effective thickness of armour - Due to angle this could increase effective armor by up to 50%
Type of AP round -APHE , AP,APCR  
On the Pk 36 APHE penetrates 41mm the APCR 79mm.  Also the same 37mm AP round from the 3.7 L.89 Flak 43 penetrates 128mm
Quality of round - Again late war german stuff was not as good, due to production issues


For 1:200 I think you just nee to take it into consideration in a more abstract way. like BKC.

If you really want to go into it for your rules I have gun penetration data from Bovington for almost all guns during the war and effective armour thickness calculated using the average angle of the plate. I could email these.

PS. I am still waiting to be PM'd your address to post that CD to you

[sultanbev]

Not sure of the question you are asking in context of game play. I assume for some kind of skirmish game if you are using actual figure scale for ground scale?

Unlike in WoT and similar computer games, it was very rare for tanks to be jousting at 100m or less. 750m was the average tank battle range in European terrain, so using the penetration figures for 400m would be a nice kind of split the difference.

Still trying to work out what a 95mm QF gun, not one I've heard of in the British army. Unless you mean the howitzer, as mounted in CS tanks, in which case it doesn't have an AP type round, only HEAT for anti-tank work, so it's penetration is constant at all ranges.

[Last Hussar]

The data is from here,  looks like its a bad example

https://wwiitanks.co.uk/FORM-Gun_Data.php?I=25

I'm guessing he did the calc not realising it was HE only

Here's another example, 6pdr

https://wwiitanks.co.uk/FORM-Gun_Data.php?I=14

I looked at loads of different sources,all different, few containing straight forward stuff. This is the most comprehensive that seemed to give the best average of all the sources, and seemed to encompass the combinations.

All sources seem to be theoretical, mostly algebra based occasionally with some fiddling around to make it fit test firings.

Because there is no way to tell how every shot will be hitting I am using their effective thickness of the hull.

https://wwiitanks.co.uk/FORM-Tank_Data.php?I=577

Because the rules are infantry based, there will be very few tanks in a battle as it stands. The table represents 400m x 240m,and there needs to be a lot of terrain to interrupt line of sight, so the tanks aren't going to see each other at long ranges anyway.

For infantry fire it is abstracted- you can't calculate number of bullets etc. It was a matter of fiddling about until the averages of what happened felt right. I wrote a spread sheet to simulate lots of dice rolls: 30 attacks at a time.

Tanks are different, its one shot that hits or misses, which penetrates or doesn't. I used the binominal distribution function to tell me the % of the rolls: the gun and armour stats are abstracted in the final game. (Bi nom dist you tell it the odds of success, number of tests, and how many successes you want. So for 50%, 3 tests, 1 to 3 success, that's 87.5%).

Because the rules have delayed resolution you don't know until the stand activates what you've done. With infantry, you know how many fire points you've put on, but you don't know the effect. With tanks you know if you've hit, and there is a chance the tank will brew up, but otherwise you don't know until it activates whether you've knocked it out. To calculate penetration you roll d6=PEN. 4+ is a success. If successes =>Armour then its a k/o.

I think the 6pdr has PEN 6, and PzIV F ARM 4. (I'm doing this from memory). That gives a 34% chance to kill. (Assuming you hit); you need 4 rolls of 4+ on 6 dice.

[Lord Kermit of Birkenhead]

 Mark Bevis will shoot me down on this but I always used the 30 degree slopped pen value. So do most other people to take account of the irregularites of the ground and ammunition etc. Also I take the front armour as being the 180 degree arc accross the front since stuff hitting the side at very oblique angles will tend to bounce off. Best tables for penetration are in Fire and Movement which was published by the tank museum many many years ago, but there is one mistake the US 75 and 76 figures have been reversed.

[Norm]

The following link to armour penetration charts is well worth book marking. It contains the largest number of charts in one place that I have ever come across.

LINK
http://mr-home.staff.shef.ac.uk/hobbies/ww2pen3.pdf

though it becomes immediately obvious that there are variables on the same gun in different charts.

I think that dice are essential in gun / armour calculations to take care of all the variables such as strike angle, weak spots, welds, joints and just that general thing of luck, rather than mathematically trying to represent all of that. So I would tend to look for gun / armour stats, modify for anything notable such as obvious slope or obvious high quality / low quality metals and then let the dice do the rest.

A 'point blank' range does need to be in the rules because those sort of situations happened, but a again that might be a factor that is worth representing by giving an uplift to the dice rather than trying to work out actual penetration increase, especially as a lot of charts don't give stats for such extreme close ranges.

[Last Hussar]

I did use that Norm, but its patchy because its a compilation of different studies.

The question is:

In a game which is mostly infantry, and a normal 6ft table equals approx 400 m, which range data is the best to use? Should I go with 200m or 400, to fit the table, or take the 800 m data to assume real world performance will be worse than studies?

[Lord Kermit of Birkenhead]

If that is your range a single strike value would work but you might reduce by 1 for 300m+. Most weapons would be balistically flat except the PETARD but that only ranges 200m.

[steve_holmes_11]

I'm going to skip the question with an observation of rule design.

I find it best to identify "non core" elements of the game and streamline, abstract and generally speed them up.
Let me provide an example - several big battle Napoleonics rules have skirmish fire phases that are about as enjoyable as a bad visit to the dentist.
Not only are lots of dice rolled slowly, but skirmishing occupies a disproportionate amount of game time.

You may decide that armoured combat is "non core" in your infantry game, and you don't want it taking ages to conclude.
In general the more effort to make it "realistic" by capturing details (What's the angle? is that face hardened armour? does the round have a ballistic cap?) will make it slower and detract from the infantry battle.
I prefer the other kind of realism: Armoured combat at close ranges was swift and brutal, and i like the rules to reflect that.
Infantry had plenty of options to hide and reduce the rate of combat resolution, close up tanks generally didn't.

My suggestion is to rate guns and armour in 3 bands: Almost certain kill, maybe and almost impossible kill.
Then roll to save: 6 only on the almost certain, 4+ on maybe and 2+ on almost impossible.

You can then draw up a matrix for just the guns and vehicles that are actually involved in your fight.
This avoids the problems of an open system which ranks all guns and vehicles (Just in case your JagTiger takes a shot at a Polosh tankette).

[Lord Kermit of Birkenhead]

To nay say Steve in close terrain you can't see anything. Also very odd things happen - DEc 44 2 Chaffes manned by crews untrained on that type killed 2 Tigger II (actually more likley Panthers) with 1 shot each using HE. OK I don't think the rules should allow that but don't simplify it to far.

[sultanbev]

https://wwiitanks.co.uk/FORM-Gun_Data.php?I=25
I have seen that site before but dismissed it when it showed nearly all guns something like 98% chance of hit to 800, then drops off exponentially after that. There would be a drop in accuracy between 100m and 800m.

Having checked the data with penetration formula here:
https://wiki.warthunder.ru/New_formuls_for_calculating_of_the_armour_piercing

(To get the % drop in muzzle velocity over range, 250 divided by the calibre of the shot in mm is the % drop in mv for each 250m.)

There is absolutely no way a hypothetical 95mm shell at 503m/s is going to penetrate 165mm/90* at 100m range. The high velocity 94mm 3.7" AA gun reaches something like that value. So the calculated values are very suspect. Some of the other values are all over the place, either too low (.50" HMG) or too high. According to that website the 3" M5 on the M10 3" GMC can penetrate a Panther hull at 200m. Even weirder a Soviet 152mm howitzer can penetrate a Tiger II turret ~300m. It quotes 17pdr AP as better penetration than APC, and doesn't even list APCBC and APDS.

Wow, look at British 3" howitzer, apparently it can penetrate a Tiger I at 800m with a 90% hit chance, even a Panther turret at ~300m. if it was that good, every British tank would have been armed with a 3" CS howitzer (lets overlook that it didn't even have an AP round....)
I would avoid it like the plague.

[Lord Kermit of Birkenhead]

Mark the only actual figure I know for ballistic drop is for the 20pdr and its 6' in 3000m. The big guns are virtually flat, the 95mm Howitzer fired HEAT so penetration is standard at all ranges its something like 1000-105mm.

[steve_holmes_11]

To nay say Steve in close terrain you can't see anything. Also very odd things happen - DEc 44 2 Chaffes manned by crews untrained on that type killed 2 Tigger II (actually more likley Panthers) with 1 shot each using HE. OK I don't think the rules should allow that but don't simplify it to far.

Tigers rolled a 1 to save.

I do very little WW2 but am a member of the "You can always miss, and everything might be killed" school.
I think it's a hangover form the Airfix days, when each side had a box of infantry and a tank.

Top tactic:
  Focus all small arms on the enemy bazooka / panzerfaust.
  Kill the enemy tank.
  Surviving tank rolls round the battlefield HEing, machinegunning and squashing the enemy infantry while your lads enjoy a beverage.

The rules were a bit limited and only proper guns or bazookas could hurt a tank.
I've learned a lot since then.

[Duke Speedy of Leighton]

Wasn't that how it worked in real life?
And only if you make dakkadakka sounds.

[Lord Kermit of Birkenhead]

THev DakDakDak sounds are for 'urricanes in 1940 Will. Ground guns go DuggaDuggaDugga