Turret hits and the poor ole PZ-IV

[Michael Emrys]

Originally posted by Treeburst155:

With center of visible mass aiming, you would only have a higher absolute number of turret hits on a hull down vehicle if the Chance To Hit did not go down enough to counteract the center of visible mass aiming. The percentage of hits that impact the turret SHOULD be higher because you can't hit the lower hull at all.

That's why I was asking for a count of the absolute number of hits on the turret per thousand shots fired. I agree that the percentage of hits on the turret compared to the hull should increase, but not the number. In other words, there should be more clean misses, both in numbers and percentages.

Michael

[ February 03, 2004, 03:03 PM: Message edited by: Michael Emrys ]

[Treeburst155]

Here ya go, Michael, the answers:

In the previous hull-down hit distribution test, 377 hits out of 512 hits were on the turret.

I've just run the same test, but with the hull down status removed. Out of the same number of hits (512), only 171 were on the turret. The number of turret hits was more than cut in half with the hull exposed.

Here's the full results of the hull UP hit distribution test:

Lower Hull - 15.6% of all hits, or 80 hits

Upper Hull - 51.0% of all hits, or 261 hits

Turret - 33.4% of all hits, or 171 hits

Track hits were counted as lower hull hits, and Gun hits were treated as turret hits, unless coupled with an upper hull hit, which does happen occasionally.

It should be kept in mind that these figures deal only with hit distribution, not chance to hit. Given a hit, these figures tell us the chances of that hit impacting on any one of three plates on the target.

So, a hit on a tank is less than half as likely to be a turret hit when the tank is fully exposed; BUT, this fact must be coupled with the increase in Chance To Hit with the fully exposed tank. My brain has not yet processed this relationship yet. I'm taking a break now before thinking about it.

[ February 03, 2004, 05:04 PM: Message edited by: Treeburst155 ]

[Treeburst155]

Hypothetical,

Chance to Hit hull down tank: 25%

Chance to hit same tank hull up: 50%

Chance of any single round hitting turret of hull down tank = Chance to hit x .75 (.25 x .75 = 18.75%)

Chance of any single round hitting turret of hull up tank = Chance to hit x .33 (.50 x .33 = 16.5%)

With these example chances to hit, the hull down tank's turret is MORE likely to be hit than the turret of the fully exposed tank. This is with a 50% reduction in chance to hit when the target is hull down. In CM, this reduction is probably less considering my Regular 37mm gun crew only got a 40+ % reduction at 700 meters.

EDIT: To summarize, the high chance of a hit being a turret hit when hull down (75%) more than compensates for the reduction in Chance to Hit due to the hull down status. If you want to minimize the chances of your turret getting hit, and don't care if the hull gets hit, you want to be hull up. This goes for any vehicle in CM. The important question being, "Do I care if he hits the hull?"

[ February 03, 2004, 05:16 PM: Message edited by: Treeburst155 ]

[Conscript Bagger]

Statistics ain't my strong point, but I'll try anyway:

If it takes more shots to hit a hull-down target, which it should given the lower To Hit percentage, then the firer is getting an aim bonus on subsequent shots (though I don't know how much of one, nor how many shots it applies to). Then the test only gives an average, and it does not work for any given shot (because earlier shots have lower percentages than later shots).

My own hypothetical:

1. If the aim bonus is 4%, and it is added to each shot until the target is hit...

2. If it takes an average of 4 shots to hit a hull-down tank, and 2 shots to hit a hull-up tank (25% and 50% from Tree's hypo example)...

Then:

I. Chance to hit target at all

Hull down

1st shot 19%

2nd shot 23%

3rd shot 27%

4th shot 31%

(Avg 25%)

Hull up

1st shot 48%

2nd shot 52%

(Avg 50%)

**************************

II. Chance to hit turret

Hull down

1st shot 19 x .75 = 14.25%

2nd shot 23 x .75 = 17.25%

3rd shot 27 x .75 = 20.25%

4th shot 31 x .75 = 23.25%

(Avg 18.75%)

Hull up

1st shot 48 x .33 = 15.84%

2nd shot 52 x .33 = 17.16%

(Avg 16.5%)

Most hull-up hits would occur before the aim bonus has accumulated much, while most hull-down hits happen after. But the chance of a turret being hit on the first or second shot is very similar whether hull-down or hull-up. In this case, hull-down would be an advantage to the Pz IV, since even a non-penetrating hull hit can cause shock, track damage, etc. In fact, the most advantageous way to fight the Pz IV would be shoot-and-scoot in a hull-down position, which "resets" the firer's hit chance for each engagement. With the long 75mm's greater accuracy, the Pz IV should win first-shot fights.

But, I have probably missed some basic mathematical concept. Now I shall await my comeuppance.

[Treeburst155]

I did not consider the improved accuracy with each shot. I'm not sure it matters. My testing involved only first round hits. Are the improvements proportional to the original chances? IOW, if the chance to his is 50% when hull up, and 25% when hull down, is this 2:1 ratio maintained as successive shots are fired?

[Mr. Tittles]

The center of mass on a Panzer IV turret is where the increased armor is! Both the shielded mantlet and cupola are in the center.

Most gunnery shoots at a 2 meter by 2 meter target (or thereabouts). A truly hull down tank may present a target that is less than 1 meter high. Not only is this smaller, it disrupts range estimation greatly. Its really much harder than you realize. Get the range wrong and your error spread increases.

[ February 03, 2004, 06:07 PM: Message edited by: Mr. Tittles ]

[Conscript Bagger]

Gah - brain fart. I misread Tree's reply. Good question about the proportional improvement. I suspect it's a flat bonus no matter what the original chance was, but I don't know.

But since he says he only tested first round hits, that means the discrepancy starts out bad (the original 18.75% vs 16.5%) and grows even faster than I thought.

[edit]

that's funny, I edited this post, but it didn't put a tag in - maybe this time it will.

[ February 03, 2004, 06:08 PM: Message edited by: Impudent Warwick ]

[Mr. Tittles]

The center of mass on a Panzer IV turret is where the increased armor is! Both the shielded mantlet and cupola are in teh center.

[Treeburst155]

Actually, with a fixed percentage increase for each shot, the ratio of the two hit chances changes. The hull down hit chance gains on the other proportionally. For example:

50/25

54/29

58/33

62/37

66/41

EDIT: Whoa!! This increasing accuracy would aggravate the hull down turret hit situation. The likelihood of the hull down turret getting hit increases with each shot at a faster rate than the hull up target. Must think for a minute.....

[ February 04, 2004, 12:04 AM: Message edited by: Treeburst155 ]

[Treeburst155]

Hypothetical:

1st shot Chance to Hit hull down vehicle: 25%

1st shot Chance to Hit turret of hull down vehicle: .25 x .75 = 18.75%

2nd shot Chance to Hit hull down vehicle: 29%

2nd shot Chance to Hit turret of hull down vehicle: .29 x .75 = 21.75%

3rd shot Chance to Hit hull down vehicle: 33%

3rd shot Chance to Hit turret of hull down vehicle: .33 x .75 = 24.75%

______________________________________

Corresponding chances to hit if same vehicle NOT hull down:

1st shot chance to hit: 50%

1st shot chance to hit turret: .50 x .33 = 16.5%

2nd shot chance to hit: 54%

2nd shot chance to hit turret: .54 x .33 = 17.82%

3rd shot chance to hit: 58%

3rd shot chance to hit turret: .58 x .33 = 19.14%

_______________________________________

The chances of hitting the hull down turret improve faster than the hull up turret hit chances. This makes it even MORE important to avoid hull down if you don't want your turret hit, and can repel hull hits.

[Mr. Tittles]

In reality, a HD tank is much harder to approximate range. This makes first round hits much more difficult.

I think the Silhoette number should be modified by several factors.

Lets take the Panzer IV. Its a '95'. If its HD, then this should be reduced, to reflect the covered lower parts, but how much should be dependant on several factors:

1. Crew experience. Conscript and Green experiencing the least benefit, Regular on up ramping the reduction to a maximum. This reflects the fact that it is not a refined science but rather a typical battle drill that any crew that has survived a typical training program/few battles should know.

2. Leadership. Tanks in HQ control would get a bonus from Stealth/etc. from leaders. this reflects the fact that they are sharing info through the radio net.

3. Vehicle gun depression. The better the gun depression angle, and the lower the gun is to the ground itself, results in better HD positions. An ideal HD position may just show the gun-up to an enemy. The complete hull and lower part of the turret itself may be hidden.

[ February 03, 2004, 08:14 PM: Message edited by: Mr. Tittles ]

[Treeburst155]

Mr. Tittles,

I'm leaving the grog realities to you grogs. I'm only analyzing the way things are in the game. Armed with this info, you grogs may be able to spot things that need changing. I report in-game facts. You guys get those facts changed if need be.

[Mr. Tittles]

I notice the Stug III has 80 curved armor on its upper hull. This is a collection of armored surfaces that also vary .

I put a link in the patches thread to this thread. It really remains to be seen if there is any notice of this for any further CMAK patch or CMBB final patch.

[ February 03, 2004, 08:22 PM: Message edited by: Mr. Tittles ]

[Treeburst155]

Translating all my tests into a very typical CM situation:

Mark IV vs Regular vanilla Sherman at 400 meters in good visibility with a breeze. Let's see if the Mark IV should prefer to be hull down.

According to the editor, the Sherman's chance to hit is 62% when the Mark IV is hull up. When it is hull down, chance to hit is 40%. Hmmm....this is only a 35% decrease in chance to hit...interesting.

If we keep our Mark IV hull up, the enemy has about a 20.6% chance of hitting our highly penetrable turret (.62 x .333) with the first round. If we go hull down, he has about a 30% chance of hitting our turret (.40 x .75)with the first round. This makes staying hull up very tempting. However, the 75mm on the Sherman has a decent chance of penetrating our 80mm hull at 400 meters. The actual chances of this happening are unknown. We can only guesstimate by the penetration charts. So, it's difficult to really know what to do in this typical case. Add a few hundred meters to the range, and things become very clear. Hull up is what you want to be.

[ February 04, 2004, 12:30 AM: Message edited by: Treeburst155 ]

[Treeburst155]

CMAK Hit Distribution Percentages

(with interesting fractional correlation that falls within 1.4% of my tests in the worst case)

Hull Up Target

Lower Hull - 1/6...(16.7%)

Upper Hull - 3/6...(50%)

Turret - 2/6.......(33.3%)

Hull Down Target

Lower Hull - 0/4...(0%)

Upper Hull - 1/4...(25%)

Turret - 3/4.......(75%)

[Michael Emrys]

Originally posted by Treeburst155:

Actually, with a fixed percentage increase for each shot, the ratio of the two hit chances changes. The hull down hit chance gains on the other proportionally. For example:

50/25

54/29

58/33

62/37

66/41

EDIT: Whoa!! This increasing accuracy would aggravate the hull down turret hit situation. The likelihood of the hull down turret getting hit increases with each shot at a faster rate than the hull up target. Must think for a minute.....

I don't think I have a problem with that. Assuming that with a hull-up target the aim point is center of mass, with increased accuracy the hull is going to start receiving hits faster than the turret, though the latter will increase as well because there will be fewer clean misses over time. But with a hull-down tank, the aim point will be about where the gun is and the increase in accuracy will accrue to the turret alone. I think I've got that right.

Michael

[Michael Emrys]

Originally posted by Treeburst155:

CMAK Hit Distribution Percentages

(with interesting fractional correlation that falls within 1.4% of my tests in the worst case)

Hull Up Target

Lower Hull - 1/6...(16.7%)

Upper Hull - 3/6...(50%)

Turret - 2/6.......(33.3%)

Hull Down Target

Lower Hull - 0/4...(0%)

Upper Hull - 1/4...(25%)

Turret - 3/4.......(75%)

It's interesting to me that 25% of hits on a hull-down tank are still hitting the upper hull. From this I deduce BFC is assuming only a partial hull-down configuration, otherwise these shots would be clean misses. I'm wondering if tanks and turretless AFVs haven't been lumped together in the mechanics of the game engine here. This could possibly have strange consequences for hit distribution on turreted vehicles too, depending on how this works.

Michael

[Sergei]

Originally posted by Michael Emrys:

It's interesting to me that 25% of hits on a hull-down tank are still hitting the upper hull. From this I deduce BFC is assuming only a partial hull-down configuration, otherwise these shots would be clean misses. I'm wondering if tanks and turretless AFVs haven't been lumped together in the mechanics of the game engine here. This could possibly have strange consequences for hit distribution on turreted vehicles too, depending on how this works.

Michael

I think it's because it's difficult to achieve a perfect hull-down position - to do so, you'd have to go to the spot where the enemy is expected to be, giving the driver instructions via radio as to when only just enough of the tank is visible so that it can fire it's gun. More over, in reality gun trajectories arched so that it was possible for a round to come down at an angle over any obstacles. This arching also means that in all situations a sloped armour is not the perfect deal, but that has not been modelled in the game.

[Michael Emrys]

Originally posted by Sergei:

I think it's because it's difficult to achieve a perfect hull-down position - to do so, you'd have to go to the spot where the enemy is expected to be, giving the driver instructions via radio as to when only just enough of the tank is visible so that it can fire it's gun.

Not if the descriptions of the process I've read are true, and I have no reason to doubt them. Simply, what happens is that the tank drives slowly towards the intervening obstacle, and the gunner looking through his sights calls the halt when he can see the desired area or target. Positioning may not have always been "perfect", but it was usually good enough to provide significant protection when it could be found.

More over, in reality gun trajectories arched so that it was possible for a round to come down at an angle over any obstacles. This arching also means that in all situations a sloped armour is not the perfect deal, but that has not been modelled in the game.

I don't understand this statement. AP trajectories were nearly flat except at very long ranges, where they would have expended much of their energy anyway. If you are talking about mortars or howitzers, that's another story altogether and not part of the present discussion.

Michael

[Sergei]

Originally posted by Michael Emrys:

</font><blockquote>quote:</font><hr />Originally posted by Sergei:

I think it's because it's difficult to achieve a perfect hull-down position - to do so, you'd have to go to the spot where the enemy is expected to be, giving the driver instructions via radio as to when only just enough of the tank is visible so that it can fire it's gun.

Not if the descriptions of the process I've read are true, and I have no reason to doubt them. Simply, what happens is that the tank drives slowly towards the intervening obstacle, and the gunner looking through his sights calls the halt when he can see the desired area or target. Positioning may not have always been "perfect", but it was usually good enough to provide significant protection when it could be found.</font>

[flamingknives]

Even a shell travelling at 1km/s will drop by 5m over 1km

[Edit]:

However, the amount that it will drop between the obstacle and the tank is minimal.

[Tero]

Originally posted by flamingknives:

Even a shell travelling at 1km/s will drop by 5m over 1km

[Edit]:

However, the amount that it will drop between the obstacle and the tank is minimal.

Depends on the positioning of the obstacle in relation to the target when looking from the shooters POV. Lets not forget were are not talking about 1/72 or 1/35 scale models. The obtacle can be quite far away from the vehicle it is providing hull down cover for.

[Treeburst155]

Originally posted by Michael Emrys:

</font><blockquote>quote:</font><hr />Originally posted by Treeburst155:

Actually, with a fixed percentage increase for each shot, the ratio of the two hit chances changes. The hull down hit chance gains on the other proportionally. For example:

50/25

54/29

58/33

62/37

66/41

EDIT: Whoa!! This increasing accuracy would aggravate the hull down turret hit situation. The likelihood of the hull down turret getting hit increases with each shot at a faster rate than the hull up target. Must think for a minute.....

I don't think I have a problem with that. Assuming that with a hull-up target the aim point is center of mass, with increased accuracy the hull is going to start receiving hits faster than the turret, though the latter will increase as well because there will be fewer clean misses over time. But with a hull-down tank, the aim point will be about where the gun is and the increase in accuracy will accrue to the turret alone. I think I've got that right.

Michael </font>

[Treeburst155]

As range increases, our AFV with a weaker turret than hull is more and more likely to benefit from being hull up. As we extend the range, a point is eventually found where the hull is highly resistant, but the turret is still vulnerable. This is the point where hull up becomes preferable. This point is of course dependent on the type of enemy gun we're dealing with.

[Redwolf]

Also, if you apply a statistical distribution of hits away from the center of target, and the center of target is the middle of the turret or the turret ring, then a flat turret of 1 square meter front will be a huge win over a quadratic turret of 1 square meter.

One more reason give do something about the Pz IV in CM.