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NeuralDream

 
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Post subject: Tiger I and Tiger II  Reply with quote   (Liked by:0)  Like this post
Tiger I (Germany, May 1942)
-----------------
data
front hull 100mm@34°=120.6mm, front turret 100mm@8°=101.0mm
side hull 60mm@0°=60.0mm, side turret 80mm@0°=80.0mm
rear hull 80mm@8°=81mm, rear turret 80mm@0°=80.0mm
top superstructure 25mm@45°=35.4mm
Speed: 38km/h onroad / 16 km/h off-road
Anti-Soldier: 2 x 7.92mm MG34  
Anti-Vehicle: 88mm KwK 36 L/56
Muzzle Velocity of Anti-Vehicle Gun: 773 m/s
Penetration of Anti-Vehicle Gun: (100) 120mm, (500m) 110mm, (1000m) 100mm, (1500m) 91mm, (2000m) 84mm

translated into F.A. stats
Defense: front  8/15, side 6/11, rear 6/13, top  4/7
Speed: 3  (3.2)
High-gear bonus: 1  (1.3)
Anti-Soldier: (0-1) 8 / (2-4) 7 / (5-8) 6
Anti-Vehicle: (0-1) 16 / (2-4) 15 / (5-8) 15 / (9-12) 14 / (13 - 17) 13  / (18 - 24)  13
Cost: 49.2

Tiger II (Germany, Jan. 1944)
-----------------
data
front hull 100mm@40°=130.5mm, front turret 180mm@9°=182.2mm
side hull 80mm@0°=80.0mm, side turret 80mm@31°=93.3mm
rear hull 80mm@30°=92.4mm, rear turret 80mm@31°=93.3mm
top superstructure 40mm@45°=56.6mm
Speed: 41.5km/h onroad / average of 14-30 km/h (22km/h) offroad
Anti-Soldier: 2 x 7.92mm MG34  
Anti-Vehicle: 88mm KwK 43 L/71
Muzzle Velocity of Anti-Vehicle Gun: 1000 m/s
Penetration of Anti-Vehicle Gun: (100) 203mm, (500m) 185mm, (1000m) 165mm, (1500m) 148mm, (2000m) 132mm

translated into F.A. stats
Defense: front 9/19, side 7/13, rear 7/13, top 5/10
Speed: 4  (3.8)
High-gear bonus: 1  (1.42)
Anti-Soldier: (0-1) 8 / (2-4) 7 / (5-8) 6
Anti-Vehicle: (0-1) 20 / (2-4) 19 / (5-8) 18 / (9-12) 18 / (13 - 17) 17  / (18 - 24)  16
Cost:   ?
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PostSun Jan 25, 2009 5:12 pm
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Sharpe

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I found sources that said this gun had a particularly effective HE round.

Is 8/7/6 good for a tank, middling or poor?
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I considered only the MG.

If we take into account HE rounds too, then we'll need a third attack value (Vs. artillery) that represents HE rounds of the main gun and has longer range than the MG. We can do it I guess.
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PostSun Jan 25, 2009 6:36 pm
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Why?  Don't they fire HE against infantry?

Can they fire the coaxial and the main gun simultaneously?  Wouldn't it be one or the other?  Can a buttoned up tank spot infantry targets more than 800m away?

I never gave the bow gun much consideration except at close range when the main gun had little AI capability.
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Sharpe wrote:
Why?  Don't they fire HE against infantry?

Yes, but they also attack with Machine Gun. The two would probably be equally effective against infantry.
Quote:

Can they fire the coaxial and the main gun simultaneously?  Wouldn't it be one or the other?

Yes, but it doesn't matter in our game, since eac unit can make only one attack per turn.
Quote:

Can a buttoned up tank spot infantry targets more than 800m away?

Infantry no, but artillery it would. Especially if that artillery is firing against the tank.
Quote:

I never gave the bow gun much consideration except at close range when the main gun had little AI capability.

I see. The MG of a tank is typically very effective at 200-700m. The HE is usually ineffective against infantry that are not pinned, but devastating against artillery.

At this point though, I'm afraid that the game has become quite complicated, so I'll go with your suggestion and have only one anti-soldier value.
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PostSun Jan 25, 2009 6:58 pm
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I think one is best.
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PostSun Jan 25, 2009 7:02 pm
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NeuralDream

 
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I've added the King Tiger.
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What about cover and SA's? Also, to make the DEF values fit the card needed to be fiddles with and the last range band had to be combined. 5 is the most range bands that will fit in the current config. The card may need to be modded a little. Here is a quick example:


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PostMon Jan 26, 2009 12:00 am
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NeuralDream

 
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Don't worry about vehicle cards yet. I will probably make a new template for them.

I don't know anything about cover (what it represents for vehicles and what values it should get).
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The basic system for building the tanks looks good.

I disagree with the notion of not caring about the High Explosive shells fired by tanks. That was something pretty important. The US Sherman tanks were built around the ability to fire HE shells (and AP shells), with the ability to deal with dug in infantry and pesky AT guns. The British were quite jealous of it. It shouldn't be too hard to integrate both values (using the higher of Machine Guns and Artillery if needed). WotC Pack Howitzer was 9 (0-1) /8 (2-4) /7 (4-12) right ?



I would vote for a blanket -10% inaccurate rating for most tanks as they are not ideal gun platforms. The Tiger tanks are an exception though as they were quite stable gun platforms. But for most other tanks I would go with a slight disadvantage to tank-based guns. It would make infantry AT guns more of an option as well.

Cost might be something to reconsider (later). The Tiger I looks quite cheap.


Tiger I should have SA's like 'stable platform' and, 'slow traverse' (at least 15 seconds for a 360 degree turn of the turret)

Tiger II should have SA's like 'stable platform' , 'prone to breakdown' and 'slow traverse' (at least 19 seconds for a 360 degree turn of the turret)

'Stable platform' SA could mean it fires as well as as an AT Artillery version of the 88mm gun, even when moving. (Unlike most tanks.) Since movement doesnt decrease accuracy though, I dont know if this SA fits in the system at the moment.

'Slow Traverse' (turret) SA could mean the tank has a 2 fewer dice when attacking targets that are not in its forward arc.

'Prone to breakdown' SA would mean the tank cannot move after being damaged
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Anti-soldier values should be the higher of either main gun or coax mg.
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Isnt there a mistake?

Tiger side armor:
side hull 60mm@0°=60.0mm

Tiger II side armor:
side hull 80mm@0°=60.0mm
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PostMon Jan 26, 2009 10:59 am
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Since we are trying to make all units in a historically accurate manner, we cannot suggest a S.A. without knowing all the units that have to get it. E.g. the "slow turret traverse" is a smart S.A., but it means that we'll have to take into account the turret traverse speed of all tanks and then set thresholds. "Prone to breakdown" is also difficult. Who else gets it? What stat makes a unit qualify for this S.A.? It's ok if we have only 4-5 tanks in mind (tiger gets the slow, caro armato gets the flammable, blah blah blah), but when you need to take into account all possible tanks of the war, then we need a rule, typically based on some spec.

Sharpe wrote:
Anti-soldier values should be the higher of either main gun or coax mg.

Yes, but how does one stat a HE gun? I'm not aware of any relevant study and we can't use anecdotal info for all tanks. WoTC has used MG only. My stats are the same as WoTC stats in most cases  (1MG gets 6 dice at close range, 2 get 7, 3+ get 8, etc.). My rationale is that a tank can't spot an enemy camouflaged nest unless its near, or at least that's my understanding from reading ww2 personal accounts. So, since MG and HE would both have a range of about 800 yards (range-8), I'm using one stat. Then, since HE would probably not do more than 6/5/4  damage, I'm using MG only because 6/5/4 is its minimum. Also, by not allowing anti-soldier range above 8, we allow the anti-tank guns to have some advantage.
What do you of think of this? Is it a mistake?

Having said this, do you think it's worth making guidelines for HE stats, and if so, can you make them?
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PostMon Jan 26, 2009 11:21 am
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Westentaschenschlachti wrote:
Isnt there a mistake?

Tiger side armor:
side hull 60mm@0°=60.0mm

Tiger II side armor:
side hull 80mm@0°=60.0mm

Good catch. I fixed it. Now Tiger II gets 7/13 side armor. I'll calculate the cost later.
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NeuralDream wrote:
Since we are trying to make all units in a historically accurate manner, we cannot suggest a S.A. without knowing all the units that have to get it. E.g. the "slow turret traverse" is a smart S.A., but it means that we'll have to take into account the turret traverse speed of all tanks and then set thresholds. "Prone to breakdown" is also difficult. Who else gets it? What stat makes a unit qualify for this S.A.? It's ok if we have only 4-5 tanks in mind (tiger gets the slow, caro armato gets the flammable, blah blah blah), but when you need to take into account all possible tanks of the war, then we need a rule, typically based on some spec.

Sharpe wrote:
Anti-soldier values should be the higher of either main gun or coax mg.

Yes, but how does one stat a HE gun? I'm not aware of any relevant study and we can't use anecdotal info for all tanks. WoTC has used MG only. My stats are the same as WoTC stats in most cases  (1MG gets 6 dice at close range, 2 get 7, 3+ get 8, etc.). My rationale is that a tank can't spot an enemy camouflaged nest unless its near, or at least that's my understanding from reading ww2 personal accounts. So, since MG and HE would both have a range of about 800 yards (range-8), I'm using one stat. Then, since HE would probably not do more than 6/5/4  damage, I'm using MG only because 6/5/4 is its minimum. Also, by not allowing anti-soldier range above 8, we allow the anti-tank guns to have some advantage.
What do you of think of this? Is it a mistake?

Having said this, do you think it's worth making guidelines for HE stats, and if so, can you make them?


We're going to have to stat HE rounds if the Brummbar is going to be more than a travelling bratwurst stand.  I suggest defining the upper limits (Hummel, M12, Brummbar) and scaling down to the 122, 105 and 75.
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Sharpe wrote:
We're going to have to stat HE rounds if the Brummbar is going to be more than a travelling bratwurst stand.


Lol Smile I'd prefer them to be travelling bratwurst stands, from the Allied point of view.


Quote:
I suggest defining the upper limits (Hummel, M12, Brummbar) and scaling down to the 122, 105 and 75.


Note that the Brummbaer gun and the 155mm guns have Bombardment and Blast. That effectively is a lot of 'dice', even though the numbers don't show it. The Sherman 105mm howitzer has more real 'dice' then the Brumm, but doesn't have Blast. Could be hard to figure out what does what exactly.


Giving those big HE shells an advantage against troops taking cover, would be most preferable, I think. Where a machinegun has a hard time handling a sandbag or a brick wall, a HE shell takes it out. Gun emplacements and machinegun nests would be at the biggest disadvantage here. Then again, they would normally benefit from Camouflage as well as cover.


Giving AT guns the option to be 'camouflaged' against (medium and) long range during setup (until spotted, having fired or having moved), would give them good protection. That way they can still have an advantage, while one can crank up the effectiveness of HE shells to a useful level.
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Make a formula and I'll use it.
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I think HE should definitely be considered; many tanks were built around the concept of providing infantry support, and rather than bristling with MG's they usually got a low velocity gun. Tanks that did initially get a lot of MG's (like the M3 light tank) usually had most of them removed with the first upgrade.

I personally use the highest of MG or HE (with an MG being 7/6/5 and the 75mm low velocity - Sherman, Panzer IV up to F1 - 9/8/7) for the main attack stats, and model coaxial and hull mounted MG's separately through SA's. For other calibre HE I compare the quantity of explosive filler with those 75mm, and subtract 2 dice (I think  Smile ) for a gun being high velocity (as those were less effective, the shell tending to bury itself in the ground).

Hull mounted MG's give an extra attack at 7/5/- against a Soldier in front of the unit (using the same front/side/rear hexes as you), while coaxial MG allows the Vehicle to make defensive fire attacks against enemy Soldiers moving into its hex, IF it is in a hex that doesn't give it cover.

BTW speaking of defensive fire, I have "Slow Traverse" give a Vehicle -1 to each attack die on defensive fire attacks. As turret movement and position is not modeled, you shouldn't assume it is always pointing forwards!
PostTue Jan 27, 2009 6:40 am
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Zeus wrote:
BTW speaking of defensive fire, I have "Slow Traverse" give a Vehicle -1 to each attack die on defensive fire attacks. As turret movement and position is not modeled, you shouldn't assume it is always pointing forwards!


I like this SA, that sounds pretty cool. You could tanks trying to outflank the slow traverse tanks.
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[This should go in the "vehicle AI value" thread, but since I'm quoting from another thread I don't know how to put it there.]

Back in January, Neural Dream mentioned he was not aware of any studies of the effectiveness of HE guns against personnel.  Presumably he had in mind something comparable to the studies of velocity and penetration that he used for Anti-vehicle values.  I think I have found some, as well as theoretical figures for the effective "kill radius" for the various HE projectiles.  Rigorous application of these statistics to FA vehicle AI values is a bit beyond me, but it looks like the kind of project in which Neural Dream excels.


NeuralDream wrote:

Sharpe wrote:
Anti-soldier values should be the higher of either main gun or coax mg.

Yes, but how does one stat a HE gun? I'm not aware of any relevant study and we can't use anecdotal info for all tanks. WoTC has used MG only. My stats are the same as WoTC stats in most cases  (1MG gets 6 dice at close range, 2 get 7, 3+ get 8, etc.). My rationale is that a tank can't spot an enemy camouflaged nest unless its near, or at least that's my understanding from reading ww2 personal accounts. So, since MG and HE would both have a range of about 800 yards (range-8), I'm using one stat. Then, since HE would probably not do more than 6/5/4  damage, I'm using MG only because 6/5/4 is its minimum. Also, by not allowing anti-soldier range above 8, we allow the anti-tank guns to have some advantage.
What do you of think of this? Is it a mistake?

Having said this, do you think it's worth making guidelines for HE stats, and if so, can you make them?


First of all, I think it is now clear that WOTC did not use only the machine gun for its Anti-infantry stats.  (see discussion in Vehicle AI value thread).  More importantly, there do appear to be some relevant studies of the effect of HE on infantry.  http://www.weaponsofwwii.com/forum/viewforum.php? An edited version of this thread appears below:

Quote:
Tank Gun HE Performance
by canambridge » Sun Feb 03, 2008 3:22 pm
A lot has been written about which tank gun had the best anti-armor performance, but there is disappointingly little about HE. The major reason the US Army didn't switch to the 76L55 gun (and 17 pdr) pre D-day was because of the poor HE compared to the 75L40.
Does anyone have any information about the HE charge of the major tank guns of WWII?

German:
37L46.5
50L42
50L60
75L24
75L48
75L70
88L56
88L71

Soviet
45L46
57L73
76L41.5
85L53.9
100L59
122L48.5
152L20

US
37L53
75L40
76L55
90L52

British
40L50 (2 pdr)
57L50 (6 pdr)
76L55 (17 pdr)
76L49 (aka "77mm")

Re: Tank Gun HE Performance
by Gryle » Wed Feb 06, 2008 4:39 am

Just bear in mind that the type of explosive and the grade of steel used for the shell can make quite a difference. Also there may be more than one mark of HE shell for any gun.

From "World War II Balistics: Armor and Gunnery" Bird and Livingston.  They indicate this is mostly from a British report PRO WO 291/955 hence all weights are in pounds.

German
Shell Total weight (lb) HE filler (lb) % HE Notes
50mm 4.5 0.4 8.0% Pzgr.Patr KwK
50mm 4.2 0.4 8.8% Sprgr.Patr. 38
50mm 4.6 0.5 11.8% Pzgr.Patr.KwK 38
75mm 9.8 1.0 10.2% Sprgr.34
75mm 12.6 1.9 14.9% Sprgr.Patr.KwK(34)
75mm 12.7 1.4 11.3% Sprgr.42 (Panther)
88mm 21.0 2.2 10.5% Sprgr.43
88mm 20.5 2.0 9.8% Sprgr.L/4.5
88mm 20.4 1.9 9.3% Sprgr.Patr
88mm 21.0 2.0 9.5% Sprgr.L/4.5

Soviet
Shell Total weight (lb) HE filler (lb) % HE
45mm 4.7 0.6 12.8%
57mm 8.3 1.1 13.3%
76.2mm 13.7 1.6 11.7%
85mm 21.0 1.4 6.7%
85mm 21.0 1.6 7.8%
100mm 34.4 3.2 9.3%
122mm 55.0 8.4 15.2%
152mm 90.2 13.0 14.5%

US
Shell Total weight (lb) HE filler (lb) % HE
75mm 14.6 1.7 11.6%
76mm 12.9 0.9 7.0%
90mm 23.4 2.7 11.5%
105mm 33.0 4.9 14.8%

British
40L50 (2 pdr)
57L50 (6 pdr)
76L55 (17 pdr)
76L49 (aka "77mm")

UK
Shell Total weight (lb) HE filler (lb) % HE
6 pdr 6.2 0.4 6.5%
17 pdr 13.4 1.1 8.2%
95mm 25.0 3.1 12.4%

17 pounder and 77mm used the same projectiles, so they will be the same, however there was a reduced propellant charge HE shell for the 17pdr with a larger HE burster but there is no indication if the one mentioned here is the full charge or reduced. http://www.wwiiequipment.com/17pounder.aspx also lists a 15.4lb shell with a 1.28lb burster.

http://www.wwiiequipment.com/2pounder.aspx lists a 1.86lb HE round with a 0.14lb burster for the 2 pounder.

Re: Tank Gun HE Performance
by canambridge » Wed Feb 06, 2008 5:06 am
Wow! Thanks, I've never been ble to find much info on this. Any ideas as to why the US 76 HE was half the 75? Are there any generalizations on the effects of different HE charges? I have read that some US tankers were not concerned about the smaller HE charge of the 76 because they could make up for it by simply firing more rounds.
(looks like 4 x 76 = 2 x 75).

Re: Tank Gun HE Performance
by Notmi » Wed Feb 06, 2008 6:12 am

US 75 M2 and M3 were low-velocity guns and 76 M1 was high velocity gun. Shooting ammunition with high muzzle velocity, there are enormous forces acting on that ammunition, therefore it must be strong. When you are shooting thin-walled (=not so strong), large HE-content ammunition with high velocity, you are in risk having a catastrophical ammunition breakup in gun barrel. That might destroy the gun and kill the gun crew. Thats why low velocity gun ammunition tend to have high capacity HE-shells whereas high velocity gun ammunition has low capacity HE-shells.
Re: Tank Gun HE Performance
by Gryle » Thu Feb 07, 2008 4:14 am

It's pretty much as Notmi said, the higher the velocity the greater the stresses the stronger the shell body needs to be and the easiest way to make it stronger is to make the walls thicker, decreasing the space for the explosives.

There are exceptions to this if you compare the 25pdr to the 75mm, the 25pdr shell was made of a fairly low grade of steel so despite the fact that it's 10lb heavier and more than 10mm larger in calibre its explosive burster charge is about the same size as the 75mm, there is however an upside to this, it's the shell body that is converted into splinters, and the splinters that do the killing, so the 25pdr should produce either more splinters, or larger splinters which remain lethal out to a greater distance, or some combination of the two.

Re: Tank Gun HE Performance
by Tony Williams » Fri Feb 08, 2008 1:13 pm

There were actually three different HE shells for the 17 pdr / 77 mm, with steadily increasing HE capacity. This info is from the ammo handbooks for both:

HE/Red/T Mk 1: 13 lb 6 oz, HE content 1 lb 1 oz.

HE/HC/T Mk 1: no data, but "has a greater proportion of HE filling (HC = High Capacity)"

HE/Super/HC/T Mk 1: no data, but "differs from the HE/HC/T in having a larger HE content"

The HE loadings were given a reduced charge (I'm not sure at what point: presumably before the HC shells were used) which enabled them to use thinner-walled shells. Muzzle velocities were only about 1,650-1,800 fps.

Re: Tank Gun HE Performance
by Gunter_Viezenz » Sat Feb 09, 2008 10:36 pm
Would different types of HE fillers be more effective than others in an HE round? I am positive there were different kinds of fillers, so wouldn't there having been different in performance... or at least that is what I am thinking.

Re: Tank Gun HE Performance
by canambridge » Sun Feb 10, 2008 12:50 am
Couldn't tube pressure be lowered by using a smaller propellant charge? The US 76mm gun actually had a lower muzzle velocity and lower tube pressures than the German 75L70, yet the German shell has more HE filler. I would think that muzzle velocity would affect the range of an HE round, but that it would have nothing to do with the destructive nature of the round.

Regarding the 25pdr, wouldn't a thicker, heavier shell expend more of it's power bursting the shell, resulting in a reduced lethal radius?

There is an empirical "rule of thumb" that allows you to roughly estimate the armor piercing capability of solid shot as a function of kinetic energy (which is in turn a function of muzzle velocity and shot weight) and shell diameter. Is it possible to draw similar generalizations regarding the amount of HE and effectivness of the round in an HE role? That is, if X lbs of HE gives result Y does 2X give 2Y (or 4Y) result?

Which of the tank guns listed gave the best HE bang for the buck?

Re: Tank Gun HE Performance
by canambridge » Sun Feb 10, 2008 12:55 am
Sorry, I hadn't read Tony's post. HE shells didn't generate muzzle velocities as high as armor piercing (and thus had lower tube pressures, allowing thinner shell walls and bigger HE charges).
canambridge

Re: Tank Gun HE Performance
by Tony Williams » Sun Feb 10, 2008 1:45 am

The thicker the shell walls, the bigger the fagments created when the shell body is shattered by the detonation, and the further they will fly. Of course, if only a few, big, fragments were produced, then there would be big holes in the fragmentation pattern, so you might escape injury if the pieces sailed past you.

There is, in effect, a kind of sliding scale in the characteristics of HE shells (or bombs). For any given total weight, the higher the HE percentage, the greater will be the blast effect (which is what destroys buildings and other structures, like aircraft). But the size of the fragments is likely to reduce with the shell body weight, which reduces the lethal radius against personnel.

The USAF is very concerned at the moment to minmise collateral damage when attacking targets in populated areas, so they are developing bombs with plastic cases in order to minimise fragmentation. These destroy everything within a defined radius, but are relatively harmless beyond it.
There is an empirical "rule of thumb" that allows you to roughly estimate the armor piercing capability of solid shot as a function of kinetic energy (which is in turn a function of muzzle velocity and shot weight) and shell diameter. Is it possible to draw similar generalizations regarding the amount of HE and effectivness of the round in an HE role? That is, if X lbs of HE gives result Y does 2X give 2Y (or 4Y) result?

As far as blast effect is concerned, yes, but that tells you nothing about fragmentation. Probably the best rule of thumb would be shell weight multiplied by HE weight, although some types of HE are more effective than others.

Re: Tank Gun HE Performance
by canambridge » Sun Feb 10, 2008 3:01 am
Tony,

If I understand you correctly, then you could roughly say that the US 75mm guns HE "score" was 24.82 (14.6x1.7), the US 76 = 11.61; so that it was roughly 2 times more effective as an HE weapon.

The USSR 76 = 21.92; USSR 85 = 33.6; German (Panther) 75 = 17.78, German 88 = 46.2; UK 17pdr = 14.74; UK 57 = 2.48; USSR 57 = 9.13.
US 105 = 161.7; UK 95 (25pdr)= 77.5; USSR 122 = 462!

Re: Tank Gun HE Performance
by Tony Williams » Sun Feb 10, 2008 3:17 am
Possibly, but bear in mind that this is a "rule of thumb" which I invented on the spur of the moment to answer your question! Someone more knowledgeable about artillery than I am might well poke holes in it.

Re: Tank Gun HE Performance
by canambridge » Sun Feb 10, 2008 3:24 am
Hey, it works for me until something better comes along!

Re: Tank Gun HE Performance
by Gryle » Sun Feb 10, 2008 9:18 am
Thanks Tony, OK so there were three 17pdr HE shells. There you go you learn something everyday.

John Salt used to have a few nice pages on weapon effectiveness but they seem to have disappeared offline, fortunately I saved some of them and found them on a CD. There is bits of everything in it including these little snippets.

"The terms "vulnerable area", "lethal area" and "area of effect", when used in the context of fragmentation weapons, are used interchangeably."

Amatol - a mixture of TNT and ammonium nitrate, less energetic than pure TNT at mixtures of less than 60/40 TNT/ammonium nitrate.

WO 291/496 Anti-personnel effect of small HE shell.
Shell - Filling - Vulnerable area (sq ft)
2 pdr Bofors - TNT - 500
6 pdr HE Mk I/T/L - TNT - 1430
75mm - TNT - 3000
25-pdr - Amatol 60/40 - 3000

So the 75mm and the 25 pounder were probably about equal in killing power

WO 185/146 Effect of splinter wounds.

The following distributions of fragment sizes were observed for different projectiles:

Serial - Projectile

A - 25 pr TNT service shell
B - 95mm HE TNT
C - 25 pr Mk ID TNT
D - 95mm HE Amatol 50/50
E - 25 pr Mk ID Amatol 20/80
F - 25 pr cast shell TNT
G - 25 pr Mk ID Amatol 50/50
H - 25 pr Mk ID Ford No.7 steel Amatol 60/40
J - 25 pr Mk ID Amatol 60/40
K - 25 pr cast-iron Amatol 80/20



Fragment distribution
Fragment size A B C D E F G H J K
Below 1/25 oz No. - - - - - - - - - -
% 3.5 9.0 5.1 9.0 6.2 5.9 3.9 8.6 3.4 37.8
1/25 to 1/4 oz No. 636 855 567 792 552 642 463 973 314 1350
% 17.4 31.5 19.6 26.0 19.0 21.8 17.5 36.8 13.7 44.1
1/4 to 1/2 oz No. 188 174 148 205 145 155 132 271 92 112
% 20.6 24.0 18.0 23.0 17.7 18.5 17.7 30.6 14.2 18.1
1/2 to 4 oz No. 190 123 193 133 191 177 185 97 157 Above
% 57.2 35.5 56.5 40.0 55.9 50.9 59.6 24.0 58.1 includes
Over 4 oz No. 1 0 1 1 1 3 1 above 8 all large
% 1.3 0 0.8 2.0 1.2 2.9 1.4 for both 10.6 fragments


So the Cast Iron 25pr shell was basically converted into powder, but there is not too much variance between the others. The 95mm generates larger numbers of smaller fragments than the 25pdr.

WO 291/128 A theory of fragmentation.

The table below shows the "vulnerable areas" of various weapons, in square feet, making no allowance for ground effect. Protection levels shown are in thicknesses of mild steel in inches. Fragment velocities are in feet per second.
Weapon Filling Frag vel No prot ¼ inch ½ inch
25 pdr TNT 2200 3000 550 -
Amatol 50/50 1800 2650 - -
Amatol 60/40 1800 2000 300 -
Ford steel Amatol 60/40 1800 3000 130 -
95mm TNT 3200 3270 780 140
95mm Amatol 50/50 2800 3600 - -


While TNT may not produce a greater number of fragments it does throw them out with greater speed.

And saving the best for last

WO 291/741 Comparison of the performance of 75mm and 76mm tank gun ammunition.

The 75mm M48 is longer and heavier than the 76mm M42A1 and has greater capacity. 76mm M42A1 is assumed identical to the 3-inch M42A1. All three use the M48 fuze.

Vulnerable areas against men in the open, in square feet, are given as:
3" or 76mm M42A1 2200 sq ft
75mm M48 2900 sq ft


So in summary:
The construction of the shell makes a difference.
The type of filler makes a difference.
The 75mm gives a good bang for your buck but in terms of killing people the 76mm isn't far behind.
None of this says anything about "blowing things up" buildings/vehicles/etc. which I imagine will rely almost entirely on the actual HE content.

Re: Tank Gun HE Performance
by canambridge » Sun Feb 10, 2008 3:02 pm
Thanks Gryle & Tony.

So a 75mm (and 25pdr) have an effective "kill" radius of about 30.4 feet, and the 76mm about 26.5feet, not much of a differnece. But the 75mm has about twice the HE content of the 76, so you could say it was twice the "blast" effectiveness against fieldworks, fortifications, buildings,"soft" vehicles, etc. And the 25pdr would have had about twice the "blast" of the 75mm.

When discussing the best tank (or tank gun), we always seem to concentrate on the anti-tank performance of the gun. Which also leads to the "how could they have been so stupid" threads (and Max Hastings books) when looking at the decisions made by the allies (including the Soviets, the T-34/85 didn't appear until after the Panther shock for them either) to up gun their tanks. We seem to forget that tank killing was only one task for tanks (and this was not officially the primary role for US tanks, that was what TDs were for). I think it would be fairly easy to argue that anti-personnel and other tasks reliant on HE were actually more important than tank killing. This was after all the primary role of the best British tank of the war, the Churchill, and the Soviet SU-152 (if not SU-122) and German StuH 42.

As I said before, this is an area I have had trouble finding much information about HE effectiveness. If this is a subject you are insterested in, could you point me towards some good sources in addition to Tony's web site. I really appreciate the information you have provided.
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