eliw00d
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Posts posted by eliw00d
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Thanks! I will definitely look these over. I feel like I've looked at this site before, but never bookmarked it. The ROF information is a nice bonus.
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Thanks, guys! I figured it might, but the book didn't mention it so I wanted to make sure.
The book also doesn't seem to give any formulae for German or Soviet APCR, just American 76mm and 90mm APCR (and I think British APDS). Do you guys know of any sources for those, possibly with formulae?
Also, is there more information out there on how to apply BHN, high hardness, flaws, etc?
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In the book, there is the following:
HEAT is the only WW II ammunition where slope effects appear to follow the T/Cosine equation, effective resistance at 0 equals the plate or cast thickness divided by the cosine of the angle from vertical.Would lateral angle be factored in to effective resistance against HEAT, such as when angling armor? Such as impact angle = acos(cos(lateral) * cos(vertical))?
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I will try those forums as well, thanks for the suggestion!
I should point out that these equations are being used for a game mod, where we are trying to make a realistic armor and penetration system.
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Hello again!
Are there any other equations/formulas that one can use to figure out the effect of slope for different World War II ammunition (including tungsten)? Last year, I tried to adapt as much as possible from the book, but there are a lot of holes and the data I end up with does not always match the book. Any help would be much appreciated!
If there are any other books or sources you guys recommend, that would help, too.
Edit: I use tarrif.net as a source for penetration data, by the way.
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@Thomm
You are right! A slope multiplier of 1.35 @30° results in an effective penetration of 259.2mm @0°, just shy of the 260mm I am getting. But, that raises the following question: why does the book give a figure of 239mm @0° at a range of 100m?
The book is a wealth of information, but unfortunately it is kind of a mess.
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@Thomm
No worries, I appreciate you taking the time to answer, anyways. At one point we were using a similar approach, with cosine, but after looking through this forum and the book we realized that it is not that simple for higher angles.
I edited my post above with a few additional remarks, though.
Edit: Also, any thoughts on where to find equivalent formulas/equations for German and Russian APCR? It's strange that the section on slope effect has no mention of either.
Edit: I should point out that I took the table of a and b factors from the book and created best-fit trendlines in Excel and am using the equations from those to extrapolate data at the different angles. If there is a better way, let me know!
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@Thomm
I appreciate your response, but unfortunately it is not what I am looking for. I am trying to find the formula/equation used to get the figure in the book. Using the formula for shell types dependent on the T/D ratio, I am able to get figures nearly identical to those in the book (no more than 2% error in most cases). Here are the ones presented in the book:
Slope Effect at Angle = a * (T/D)^bWhere a and b are given in a table, depending on angle and shell type.
76mm HVAPCompound angle equals 0° through 25°
1.0000 * e^(A * 0.0001727), where A = (compound angle)^2.20
Compound angle greater than 25°
0.7277 * e^(A * 0.003787), where A = (compound angle)^1.50
Edit: Just realized after typing this that I must have fat-fingered 0.003787 as 0.0003787. I am now getting ~260mm, which is a bit higher than 239mm, but closer than ~149mm. Any thoughts as to the reason for this margin of error?
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Hello,
I recently came across a copy of WORLD WAR II BALLISTICS: Armor and Gunnery, and had a few questions.
In the book, there is a section for HVAP and APDS slope multiplier equations as a function of angle. However, when I try to use the equation for 76mm HVAP, I end up with incorrect results (when compared to some of the data found here in the forums and elsewhere in the book).
For example, trying to convert 100m penetration @30° (192mm) to 100m penetration @0° results in ~149mm, which is far less than the figure posted in the book (239mm).
I found a post here in the forums where rexford was talking about 76mm HVAP versus Panther lower front hull, and how it had a slope multiplier of 3.3 at 55°. Using the equation given in the book, I end up with a slope multiplier of 0.85, though.
So, are the HVAP/APDS equations in the book wrong? I've had no problems adapting the other formula for AP, APBC, and APC/APCBC.
Also, how would one determine the slope multipliers for German, Soviet, and other APCR rounds? I couldn't find any equations for those in the book, but I may have missed it.
I am trying to create a more realistic armour and penetration system for a game, and if there are any other resources besides this book that could help, please let me know! Thanks!
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Thanks so much for the help, guys! This has been such a wealth of information. And yes, I do understand that everything was very dynamic in war, and that there are no single figures, but designing a mod or even a game with so many variables would take entirely too long. However, we will be giving players the choice to change distribution before a game, for more AP or HE.
Keep it coming if there is more information, I really appreciate it!
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Does anyone know if the other Osprey books have ammo distribution numbers, like the Sherman Medium Tank book? Are they worth getting, or are there better books out there?
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As far as effectiveness, I wasn't thinking in terms of penetration - as that wouldn't be affected by range - but of accuracy and range (being affected by muzzle velocity). But that still begs the question as to whether or not HEAT was more accurate with longer barrels? I would assume so, but in practice?
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@Narses
Thanks for that! Funny thing is, that was my source for the Germans getting between 1-3 rounds per Panther/Tiger earlier on in the thread.
As for the HEAT, I have a feeling that German HEAT rounds were probably disliked because they were fired out of short barrel weapons, which made them ineffective (lack of muzzle velocity). I wonder how the StuH42 with its HEAT rounds faired, since it had a relatively long barrel? From the data we've gathered, it seems that the M4A3(105) HEAT round was pretty decent, although not as good as conventional AP or HVAP.
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Would the up-gunned (for lack of a better term) tanks have slightly more AP, as costard suggests? Tanks in question being M4A3(76)W and Sherman VC Firefly. I think someone earlier in the thread said that even though the HE was weaker in the 76mm, they still had about the same amount.
Also, a friend of mine recently debated about the naming of a particular round, WP/Smoke. Did all nations use WP for their smoke rounds? Or only the Allies? And if they all did, would using WP generically suffice to describe smoke rounds of all nations?
And as far as HEAT, from what I've been able to gather, it would be a smaller percentage of a vehicle or crew's distribution because it wasn't their primary duty, but more of a defensive round. Is that correct? So, for example, an M4A3(105) would have something like 70/20/10 (HE/HEAT/WP - did they have smoke rounds?).
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Actually, I read that they stopped producing APCR for anything except 5cm PaK38, but I'm sure they still had a decent amount of rounds to distribute. I'll have to get the URL when I get home, but I believe a source I found stated that Panthers and Tigers (only) would often carry between 1 and 3 rounds of APCR for use against IS-2s and other heavy targets.
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Would it be safe to assume that any shared vehicles, like the 6-pounder in American service (57mm Gun M1), would use ammunition based on their originating country? For example, since 57mm Gun M1s used APDS, did M10 Tank Destroyers in British service use HVAP?
So far, and until better sources are found to change this, I think I will go with something like this:
M4, M4A1, M4A3: 70/20/10% (HE/AP/WP)
M4A3(76)W: 70/25/5% (HE/AP/HVAP)
M10, M18, M36: 20/60/20% (HE/AP/HVAP)
Sherman V: 70/20/10% (HE/AP/WP)
Sherman VC: 70/20/10% (HE/AP/APDS)
M10: 20/60/20% (HE/AP/HVAP?)
M10C: 20/60/20% (HE/AP/APDS)
I haven't found any data for the Germans, but I would assume that Panzers/Panthers/Tigers would have a similar distribution to Allied tanks, and Marders/Jagdpanzers/etc. would have a similar distribution to Allied tank destroyers. Obviously APCR would be a much smaller factor for them.
Thoughts?
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eliwOOd,
Welcome aboard!
These should help.
57 mm APDS: Scale of issue and actual combat use
http://www.battlefront.com/community/showthread.php?t=47318&highlight=apds
U.S. HVAP ("T" in the game) availability and scale of issue
http://www.battlefront.com/community/showthread.php?t=1324&highlight=apds
75 mm Sherman load and type split
http://www.battlefront.com/community/showthread.php?t=46464&highlight=apds
Crash course on 17 pdr and 77 mm guns, ammo, production stats
Sherman Firefly specs, but no ammo split (deduce from previous link)
http://www.onwar.com/tanks/uk/data/firefly.htm
This should help enormously. Tech specs (inc. ammo stowage) on U.S. AFVs of WW II circa 1944
The above plus many other such volumes in one handy well-illustrated book
http://www.amazon.com/American-Arsenal-Antiaircraft-Ammunition-Paperbacks/dp/1853674702
TM9-1901 Artillery Ammunition (grog fest; covers 20 mm -240 mm)
http://www.scribd.com/doc/24436830/Tm-9-1901-Artillery-Ammunition-1944
Regards,
John Kettler
Thanks, John! The first three links are the ones I mentioned earlier, that I found by searching (using the very same term!), but the others are all new to me. I haven't actually looked at the numbers in detail, but do you think taking the number of guns produced and the number of each ammo type and trying to come up with a distribution based on that could work? Or would that boil down again to what was actually issued or requested by battlefield commanders? I'll be looking through all of these today, see what I can get. Thanks again!
The Osprey Ordinance catalog is pretty good, but it doesn't seem to list how many rounds of each ammo type were in the tank, just that it had X amount of rounds, and the types. I already have the information for the amount of rounds each tank had, from here:
http://afvdb.50megs.com/germany/
And some other sources. If only it had the amount of AP/HE they carried, but I understand that it's just giving the maximum capacity in stowage. Good source, though!
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OK, this is for British Airborne AT units:
"Both types were well provided with the new and still secret “Sabot” (APDS) ammunition which could penetrate any German armour then known and, thus equipped, the 6-pounder with its lower profile was claimed to be the most effective anti-tank gun in service at the time. The 6-pounder traveled in a Horsa glider with its jeep, gun detachment and ammunition. The long barrel of the gun did not permit space for a trailer so the ammunition had to be accommodated in and around the towing jeep. Forty two rounds per gun were carried of which fifteen were normal armour piercing shot (APCBC) and twenty seven were Sabot (APDS). The 17-pounder, being longer and heavier, was carried in the larger Hamilcar glider along with its towing vehicle, a specially adapted Morris Commercial which carried the gun detachment and the ammunition consisting of twenty armour piercing (APCBC) and ten Sabot (APDS) rounds per gun.
I found this here but it's quoting the same book I was going to use anyway.
Excellent! That's the kind of stuff I'm looking for! Do you think Airlanding received higher priority, then? Or could I use that for regular and Royal Artillery as well?
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I appreciate that, it does make more sense now that I think about it.
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So, looking at section 16 of the rules, I can't seem to find anything about % or number of rounds allocated. Hmm...
http://files.boardgamegeek.com/file/download/lxm0mqlmr/PattonsBest-rules.pdf?
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I seem to remember that the boardgame "Patton's Best" (I *think* from Avalon Hill but I'm not 100% certain) had charts for average loadouts for different types of Shermans. How accurate those were I have no clue. I'd post an example but I can't find my copy, dang....
That would be a great find! Especially if the loadout for a 75mm Sherman matched up with what I found in these forums (from the Osprey book). Anybody have this game lying around?
Actually, a quick stop by Boardgamegeek brought this to my attention:
http://files.boardgamegeek.com/file/download/1nel637qpb/MiscellaneousTables.pdf?
Is that kind of what you meant?
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If you ever want to really bust your ass on this—and I am not insisting you have to—you could poke around to see if you can come up with the daily logs of the supply organizations of the various armies. US and UK figures might still be around somewhere, but I'm doubtful you could find anybody else's without a lifetime of searching.
Michael
Well, I don't know if I want to get that in depth on the subject, I was kind of hoping there'd be more information out there like the Osprey book, with the percentages. I know it's probably not that simple, but that was definitely a great find. If anything, we could probably just use that as a base and guess as to what a crew might have based on doctrine and what not. So, for example, a 76mm Sherman might have a 70/20/10% split in favor of AP/HE/HVAP (50/14/7 rounds respectively) or something like that (since the 76mm HE performed less favorably tha the 75mm). I would assume that Germans would probably have a similar split, but probably more in favor of AP than HE, but I don't know anything about that other than simple guessing.
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You cannot count on any particular figure as being carved in stone. The loadout of a given tank/TD/ATG on a given day would depend on what the unit's commander and crews expected their needs were going to be, but much more importantly as some posters have already indicated, on what was available. Logistical support networks tried to maintain a supply of the various types in certain ratios, but that system could break down for any number of reasons. And I suppose the requests of unit commanders were sometimes respected, supply permitting.
BTW, since the differentiation in roles between tanks and TDs in US service in practice were not so clearly defined as envisioned, they sometimes found themselves swapping 76mm ammo. The tanks would give up HE and receive in turn HVAP. I've read nothing so far that suggests that this happened on a large scale however.
Michael
I understand, but I'd like to find any information, whether typical or atypical, just to get an idea of what we can use in our mod. I also know that doctrine at the time was for tanks to break through enemy lines and support the infantry, while tank destroyers were meant to take out enemy tanks behind the infantry and tanks...yet that changed quite often on the field. However, when you try to incorporate everything that happened in the war, it becomes much harder to be authentic because there are so many variables. I'm just looking for whatever I can get, and then I'll compile all the information and try to make sense of it in game terms. For instance, knowing things like the Sherman having a 70/20/10 split for cannon rounds is bliss, because that really helps us assign numbers in game. The availability of all the specialty rounds and the number issued was never a sure thing, but a general number from D-Day through the end of the war could at least give us a percentage to further split the above. That's all.
I read something in these forums about an anti-tank commander suggesting an increase in APDS for his 57mm, after seeing its value in battle. They were actually given 6 rounds on paper, and he suggested 30, IIRC. The fact that he had 6 on paper is at least a good indication that we should be shooting for 6 out of so many rounds (thus a percentage).
I appreciate all the info so far, it's really helping. I may have to look into some Osprey books and what not to get more percentages, it seems. Again, I know it wasn't always the distribution, but that's where we can at least guess and come up with other options the player can use (like sacrificing HE for HVAP like you suggested).
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The 17-pr was the best A-Tk of the war, and severely overmatched any German armour. It's requirement for APDS was therefore limited. Some was made, but I have no idea about quantities, nor quantities issued.
I read somewhere that vehicles were given somewhere between 5-10 rounds of APDS, but they didn't specify which vehicles or anything. Have you ever heard anything like that?
Message #1, Paragraph 5:
http://www.bbc.co.uk/ww2peopleswar/stories/06/a2187506.shtml
Turret Traverse Speeds (WWII)
in General Discussion Forum
Posted
Is there any data on the turret traverse speeds of some of the more "obscure" AFVs of WWII, such as the PzKpfW 38(t)? What books or websites would you recommend for finding this type of information?