ww2steel

Yes, (if my chart is showing up right on the last page) at 30 to 50°, if the turret is straight ahead, the HC round 0f 1942 has less than 90% the power required to penetrate the Matilda. Below 90% very few penetrations of any kind occur. The 90% armor quality increases the standard deviation, so penetrations can occur at a slightly lower achieved penetration than normal. The graphs show the front of the vehicle towards the top of the page, showing the vulnerability af the turret, upper hull, and lower hull. Red is 110% power to armor thickness, orange is >100%, yellow is >90%. Red almost always penetrates, yellow rarely penetrates, and outside yellow almost never penetrates at all. Overall takes the weakest panel at any given angle and displays the range at which it can be penetrated. If you have a Matilda, turn the hull about 40° from the PzIV and hope you don't take a round in the turret face. If you do, at least there's a chance it won't do any damage. This is good practice for most tanks, though the angle may vary slightly.

This is from the old version of my program. (New one is down for work right now). Please excuse the poor graph resolution (10°, 100m), the new version goes down to 1° and 1m. Hope the big pic isn't too annoying. This gives a pretty good representation of the 360° vulnerability of the two tanks to eachother. Click the pic for fullsize. Website's in the signature.

Diesel, if you've seen my website you know I have much more data than shown. The Matils were almost always KO'ed because (as you certainly know) an HC penetration does many many times more damage than an equivalent penetration by 1942 2pdr shot. These tests are only for one turn/minute, because generally in the game after one minute of tank on tank combat the situation has changed as such that any two tanks that have not killed or damaged the other by the end of the minute then they probably wont. As far as counting tactical kills- a gun damaged tank is mostly worthless except for exposing enemy AT guns that shoot at it and maybe pursuing infantry with a bow MG. A tracked tank is a pillbox, and much more easily dealt with- especially if a green crew abandons the tank. I like CM because it reflects real life as well as possible, I could care less about points. If you are a points player, it should be agreeed that a tactical kill should at least count to some percentage as a KO. (A LARGE % IMO) I never mentioned platoons, I took 100 of each vehicle as loaded in Feb'42. The loadouts are in the first line my second post. Besides, who cares how many rounds the Matildas carry (it's actually 93 if I remember correctly) when 90 of them are burning in the racks on 50% of them. (I see you are in London, gotta give you a little ribbing here.) I don't think I have any 'wrinkles' in the methods. I was testing HC versus the Matilda's frontal armor to inspect why it was presenting 'None' instead of 'OK'. Why would I consider side armor in these tests? Also, you didn't have to deduce that it was a frontal engagement, it says it right in the text. If you have a better way to 'field test' 1400 tanks in a statistically significant way that can eliminate all user bias, I'm all ears. See ya, Mike

The results: The computer displays the kill probability by looking at ammo in this order: T, AP, HC, HE If it has no T then it looks at AP, etc. So, if it has T on board, it displays that. If it has AP on board, apparently (at least on the PzIVF) it will not display HC, even though it is generally better. Deleting all of the AP gets it to show HC kill stats. CMBB does this as well, I checked. The matchup between the PzIVF and Matilda II in 1942: (shows any tactical kill- aban, KO, bailing, gun damage, immobile) 100m PzIVF=22%/Mat=71% 300m PzIVF=12%/Mat=67% 500m PzIVF=5%/Mat=59%; 47% first round hit for PzIV, Mat usually pops smoke >=500m 750m PzIVF=0%/Mat=67%; Matil fires infrequently 1000m PzIVF=0%/Mat=67% 1500m PzIVF=0%/Mat=67%; 5% PzIV 1st round hit, Matil does not fire at >= 1500m 2000m PzIVF=0%/Mat=67%; 1% PzIV 1st round hit These are results of 700 pairings (1400 tanks), frontal engagement, played 2 player, no orders given, seperate pairings cannot see eachother

Actually, at the date I tested (Feb'42) HC WAS the common AT round. Roughly 5 standard AP are carried and between 0 and 16 HC are in the racks. I agree, CMAK must be measuring the standard AP. The 7.5cm L/11 IG that does not carry AP shows that it can penetrate. Upper hull results (75mm, 0°, 90% quality): 208 hits tests Full Pen (>67.5mm pen achieved): 152, 73% Partial Pen (>58mm): 53, 26% Internal Armor Flaking(<58mm): 3, 1.4% No Significant Damage: 0 I think I underestimated the standard deviation a little (I don't know how much CM increases the SD for low quality armor, I'm just guessing based on a Rexford post). The ranges I have done so far: (number of tanks disabled - Imm/gun/destroyed/bailing) 100m PzIVF=22%/Mat=71% 300m PzIVF=12%/Mat=67% I will eventually take this out to 2000m and repost. This is for unaltered ammo loadouts (maybe about 4% don't carry and HC and generally are a writeoff), regular crews, 100 tanks per side-per test. Clearly the PzIV has an advantage... too bad they even pop smoke and reverse occasionally. CM does simulate the extremely poor accuracy, but I agree that it is maybe not harsh enough for some ammo (and too harsh for others). I will try deleting all HC and seeing how it displays. I will also look at it in CMBB which I am extremely familiar and see if it does the same, I don't think CMBB does this. I am nearly certain that CMBB looks at the best penetrating (maybe not most lethal) ammo on board and gives you the kill chance for that ammo. More after I get some sleep! Mike

I just noted today that the PzIVF (7.5cm L/24, HC, Dec'41-Dec'42) when you point it at a Matilda shows the chance of a kill as "None". This seemed odd, since the round is capable of penetrating 82mm @ 0°. The 75mm armor, with angles as low as 0° should be easily penetrated. You don't really need to do the math to figure out that it should penetrate easily, but: Assuming a standard deviation of a little under 10%, with 90% quality armor it should have a 98.7% chance of FULL penetration. It should have, literally, about a 99.998% chance of at least a partial penetration. Actual game test results do not come up quite this high, but close. Why does the game engine display "None" to the user? Mike

I agree, it would be nice if there, even if they just used generic values like -10, +20. Sometimes I have seen really ridiculous angles. I have not tested that there are really NO limits, but it is not historically limited. I do understand why they do not have historic limits- simply because the data is often very hard to impossible to find. I think I might do some tests tonight to check this... will post. Mike

Makes sense- that the long guns would wear out faster given the much higher stresses of pushing a similar sized projectile with at least 4x more powder out the barrel. Cool info. Realistically though, with the exception of artillery guns I think any WW2 army would be being very optimistic if they thought that many standard issue tanks would last long enough to go through 500 rounds, even given practice shots. I wonder, does anyone have info on how many rounds was a normal service life for a tank gun (before being toasted)? How often did armor actually require gunnery refits due to wear. (Not counting self propelled artillery.) Mike

Low velocity guns were the standard for the 'large bore' guns pre WW2 (the 75 being considered large bore then). It's simply a howitzer put into a turret. It has the advantage of being less restricive in close quarters combat (woods, urban, etc) because the turret can turn much more easily than a clumsy long gun on a Panther or something. You also have to worry about planting a long gun into the ground when descending a steep trench, poking it accidentally into a building while maneuvering, etc. Short gun tanks are easier to transport. These last few reasons are why you often see tanks that are not in a combat area with the turrets turned to the rear. The short gun of the PzIV was due to an order (I think maybe directly from AH??) that the tanks were not to have an overhang of more than the length of the hull forward the turret. The BT-XA and T-26A, along with the early T-28 land battleships; the PzIV; etc. were examples of infantry support where armor penetration was not the issue. Getting a potent HE round on target was the issue, and a slow round - with a higher trajectory - can actually be advantageous sometimes (though harder to hit a target with the first round). Also, circa 1938, a short 75 AP could crush nearly anything fielded. Also consider that these were not intended to be the tank killers. They were capable of destroying enemy armor, but a BT-5 or PzIII with a smaller medium velocity gun was more capable (flatter trajectory makes for better accuracy, you could load and fire a 45/50mm gun much faster, you can carry more of the smaller ammo, etc.). It was later in the development stage that medium 75s and similar were fielded. This is the point in technology that I personally count as being a WW2 era tank (not so much the gun fitted, but the technology state... I obviously count a PzIIIL as a WW2 tank- barely). The T-34, M3 with the side sponson, and finally the Germans with the PzIVF2. It was finally clear that these specialist tanks were a liability, and without much more consideration a multipurpose tank was created that could perform adequately for both roles. Hope this helps, Mike

As stated in the description: 100mm AP (The BS3 antitank gun). I guess I could have made that a little more clear. I have my resolution turned way up because I work in spreadsheets constantly. Sorry if you can't see it well, but that's all I can do. At 1280*1024 the image easily fits into the window with no scrolling. Mike

I hate to cross post, but since the Panther's in CMAK too I figured some of you might find my recent data interesting. I only really play CMBB unless I am testing something. Here's the link: http://www.battlefront.com/community/showthread.php?t=84522 a small pic (so we don't kill my site's bandwidth): I did a bunch of tests for the Panther tank on where the impacts hit based on range - turns out range doesn't matter (1555 tests), how the glacis plate is mathematically modelled (the results at least, it's too late at night to do the math yet), and how the 'shot trap' data comes out (562 tests between these two). Hope it helps, please don't roast me for the cross post! Mike

Hopefully the image will work... This pic of part of one of my spreadsheets gives a ton of data I have collected on the Panther series of tanks. The impact data (left chart) shows, from direct front, where the rounds strike the tank, this is from 1555 impacts, so it's pretty significant... and it took a long time. I also tested to see if perhaps the percentage of the upper hull hits increased and lower hull hits decreased with range because of the higher trajectory of the rounds, it does not, even with slow rounds (top chart). Lastly (bottom chart) I show a somewhat statistically significant chart breaking down upper hull penetrations. This data was the purpose for this entire exercise. I placed the Panther tanks at 900m, the range that my new parabolic equations suggest that the UH armor of 100% quality will be right at the maximum yield of 100mm AP. Sure enough, those that struck the early Ausf A almost never suffered any penetrations. The "occasional flaws" of the late Ausf A allowed many more partial penetrations, including a few full penetrations. "Frequent Flaws" in the G model glacis allowed frequent penetrations in this test model; 4 times as many full penetrations. Now, I understand that 562 hits is hardly stat-sig, but it gives a clear view of how the Panther glacis plate is modeled in CM, and I think it is probably modeled very well. I am impressed that they took the time to single out this problematic part and model it with (reasonable) historical accuracy! I'll do the math to approximate the 'armor quality' percentage that was probably applied sometime soon. I bet I can figure out Rexford's standard deviation / penetration percentage data to do this... but right now it's 4:30am and my brain's melted! As a side project you can see in the data that I kept track of turret hits. Though not totally stat-sig, I noticed that there were no "penetration at weak point" for the G, late turret, and wondered if these weak point penetrations were how CM handles the shot trap. Hope this is helpful to some of you! Mike

The results: Redwolf, you are correct. CM does not simulate the curved armor surfaces as viewed from the top. Purpose: To test this question. If the turret is penetrated as easily by a rear quartering shot as it is from the side then we know CM keeps track of things like round turrets. If not, then it sees the Tiger turret at least as square. Method: I used 45mm L/46, equipped with 1943 APCR. According to the closest performance equation I can get for 0° sloped armor performance, this gun should penetrate 82mm of armor at 241m. According to its stats it can do 94mm at 100m - this is where I placed the Tigers. Very few tests were needed to find the results. Groups A: Side shots. Of 21 shots to directly strike the Tiger's turret at 90°, all penetrated. 18 were partial penetrations, 3 were fully penetrations. All shots were APCR. Groups B: Rear quartering shots. The first batch fired AP only (since the computer gunners determined that APCR had no chance. 6 standard AP struck the turret side at a 45° angle, all broke up. The second batch had the AP manually removed and only fired APCR. Of 9 hits to the turret- six struck the side and three struck the rear. All ricocheted without internal effects in the least. Conclusion: CMBB takes round turrets to be squares when viewed from overhead. Speculative conclusion: All armor in CM is a simple box, or pair of simple boxes if the equipment is turreted. The only angles being used by the engine are the ones shown on the data page, plus elevation differences and obliquity to the firing weapon. (Slope, 'curved', and abstracted 'shot trap') I understand why they did it though, it's a lot of work and data storage to keep track of all that. I was certainly not looking forward to incorporating it into my penetration calculator. Since it is made to show performance in CM, I guess I don't have to incorporate it since the game doesn't! Hope this helps, Mike

Yes, check my website (in my sig) if you would like, my graphs may interest some people. That's why I stated that an "equally armored" (I meant the same thickness all around) would give the best protection at any of the 45s. (A perfect cloverleaf on the graphs) I understand that most vehicles have the best protection around 30° from front. (A small frontal bulge with big side and rear bulges- leave the adult jokes out of this ) Also, looking at the IS3 stats in the game, the upper hull is 120@56, there is no specified curve to the upper hull. It should have an obliquity of about 20° when viewed from the front. (And the turret should be 'curved' all around, not just the front.) I figure that CM MUST model this more accurately than this, given all of the other work they did, it's just hidden in the engine and not displayed. Perhaps the IS3 turret side is 'curved' but is given a slope angle of a MINIMUM of 45°, instead of a minimum of zero, like the mantlet. I understand that they included elevation too, which is cool. Just one more thing that says to me that they must have modeled the tanks better than two simple boxes (hull and turret) for penetration calculations. They did so much other very detailed stuff I figure they must have accurately modeled the larger shapes. I understand that you are saying the Tiger's turret in the game, viewed from the top, is modeled as a square. I will have to test this on my 'test track', A couple of hundred shots to the 45 of the rear of the turret and a couple of hundred shots to the direct rear of the turret should yield the same number of penetrations if it is modeled as round. If it is modeled as a square, and this is done at a projectile yield of maybe 85mm penetration, there will be no penetrations at 45° to an 82mm plate (which should be VERY ROUGHLY 125mm apparent thickness). I should have time at work today... I'll post the results. See ya, Mike

Thanks guys, I understand these features (hadn't though of supersonic transition ballistics, nor do I have any idea how to simulate them). In short, I am trying to redo CM's ballistics for my graphs, but have little data to do it with. Right now I am redoing everything use equations for each ammo type and the published angles. I take into account the armor types, guessing at how BF put them into the game (like high and low hardness RHP, high and low hardness cast, etc), applique armor, armor quality, armor slope and obliquity. One more question- does anyone know if CM1 takes into account things like the cylindrical turret of a Tiger (which should give a 'curved' effect), or does it treat everything like a KV-2 style square box with a square turret? Mike

Okay, I know that CM1 takes into account obliquity (the angle of the target vehicle armor to the attacking gun). This makes a tank that is armored equally on all surfaces hardest to penetrate at a 45° angle from the firing vehicle. Does it treat everything like a KV (turret and hull are squares as far as computations are concerned) or, does it take into account things like: The Tiger's turret is round (viewed from top)? Does a shot to the side of Tiger does it give you the same effect as a 'curved' plate as it should? The IS3 has a pike nose (actually hardest to penetrate from direct front - unusual) I could figure this out using hundreds of tests, (I may anyway) but if someone already knows... Thanks, Mike

Forgot to answer this: Normal German HTs were not ampib. The only CMBB aphibs are the T-37/38 and the T-40s, as modeled in the game. Later T-40s were uparmored, not ampib, and nearly pointless. I think they led to the T-60, but not sure without looking it up. (Not that there is much of a point to the T-60.) The only real amphib in the game is the assault boat available in the editor. Mike

A editor trick you can use, if you want to have (immobile) amphib units is to place them on open ground or similar then change it to water. (You can use the same to place them inside buildings, woods, etc. All of which cause them to be immoble.) To make it look realistic, have the vehicle "dug in" and the position locked. Mike

I looked on Gamespot under the CM screens (apparently where the above screen is located). Do any of you know where the other screens of this type are? If I remember correctly there were a couple of them. BTW, how the heck do I edit my posts??? I'm signed in but none of the buttons (on my screen at least) allow me to edit my previous posts. (frustrating) Thanks, Mike

Very interesting data and equations. I would love to know more about this Livingsto/ Bird equation and how the CM peeps converted it to a penetration percentage as shown by Charles' graphs (above). I might be able to estimate these percentages based upon the above graph, but I suspect I may be very far off. (Well, far enough off to be unacceptable to the CM community.) Mike

Hi Steve, thanks for your response. I already have calculators for slope and obliquity, taking into account published quality figures. I take into account the published stats for the different ammo (but not things like shatter gap). I will include what you said about appliqué armor next. Just to get this accurate for CM- let me ask a little more to make sure I reflect it correctly please. Let's take the PzIIC, Elefant and PzIIIL for instance. The Elefant I know is a simple bolt on 100+100 over the majority of the front hull. If I interpret this correctly, this only equals 150mm plate in CM, correct? The PzIIC is 15+20 or actually 15+10=25mm. (Which does actually mean that the 30mm PzIIF is better.) Then the PzIIIL, since it is standoff on the front, would that still equal 50+20, 50+(10)=60mm? Simply the equation in CM is (Base armor thickness) + .5(Appliqué thickness)= (apparent thickness) Correct? Can you tell me what standoff armor does to HEAT in the CM engine? Oh, also, can you clarify the Tiger's reinforced turret front and the Panther's front upper hull notes and how CM uses it. Trying not to be greedy here. (Tell me EVERYTHING!) I really appreciate it, just a couple of little tidbits like these give me a lot of programming time to play with! I did see Charles' graphs years ago, always wanted to do some similar, so here they are! Thanks, Mike

I have searched all under Madmatt, Moon, Battlefront, and Battlefront.com. The long lists kept screwing up around page 9 for some reason each time I tried. I will try to contact Charles directly. JK: (same format as before: 0°, at game pub. ranges) 2cm L/55, AP shot, CMBB 31 23 13 3 2cm L/55, AP shot, CMAK 36 24 12 2 (at the other end of the spectrum) 8.8cm L/56, APCBC , CMBB 154 142 129 105 8.8cm L/56, APCBC , CMAK 170 157 142 116 So, in these few cases at least, HE is better on the East Front, where the harder armor protects better against AP? AP does better against western RHP, which is made to protect more against attack from a howitzer perhaps? This makes sense, but I'd love to back it up with info from Battlefront. Mike

I am putting gun performance values into my calculator/ graphs. While entering CMAK data that was sent to me I noticed that the guns (German, for example) differ slightly - by maybe a few mm - from CMBB to CMAK. Is this because they were facing Western armor instead of Soviet??? I have spent some time looking through old posts, because I'm sure this has been covered, but haven't managed to find anything. Grille, 0°, HE, all dates: (one of many examples) CMBB: 37 36 33 29 CMAK: 31 31 30 26 Does this mean that Soviet armor is somehow more vulnerable to this HE ammo? Did Battlefront change their evaluation of all of the guns? What's up? Thanks for the help! Mike

Vista sucks, I've had lots of problems! Kept this new model because it plays CM games (really). Ditto on keep the old machines. Sometimes I want to play Panzer General 2 and have to go back to my old Windows 98 machine. Some of Vista is cool, but lots of problems! Mike

Wow, thanks for all the info! (kind of glad I cross posted!) I'm way tired, I'll get some sleep and then work some more on those armor penetration graphs. Mike