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Ramble on tanks, armor and other stuff...
- Thread starter [TW]Wilsonam
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Oh good grief... brief list of sources...
Key one for some of the underlying math: WWII Ballistics- Armor and Gunnery, Bird/Lingston, for a very useful treatment on the slope effects of blunt-nosed rounds (BR-354) and capped rounds (Pzgr.39). That also saves me churning through a long list of sources, as I am lazy. To quote:
Other sources worth a look - there was some post-war testing carried out by the Yugoslavs, using captured/abandoned German equipment. Also useful.
As for the face-hardening - different issue. Chewing up time this morning shows I need to re-re-check on the allowance made for the Russian ammo shattering on impact. But that is a separate discussion
of course, that also highlights the fact that the cap was designed (and effective) at preventing shattering - NOT for creating the turning moment described above. Blunt nose projectiles were far more effective at that.
Key one for some of the underlying math: WWII Ballistics- Armor and Gunnery, Bird/Lingston, for a very useful treatment on the slope effects of blunt-nosed rounds (BR-354) and capped rounds (Pzgr.39). That also saves me churning through a long list of sources, as I am lazy. To quote:
Other sources worth a look - there was some post-war testing carried out by the Yugoslavs, using captured/abandoned German equipment. Also useful.
As for the face-hardening - different issue. Chewing up time this morning shows I need to re-re-check on the allowance made for the Russian ammo shattering on impact. But that is a separate discussion
of course, that also highlights the fact that the cap was designed (and effective) at preventing shattering - NOT for creating the turning moment described above. Blunt nose projectiles were far more effective at that.
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I was asking for sources on the L/43 with the PzGr.39 repeatedly failing to penetrate the T-34's glacis at any range below 500m.
Still, thanks for all the time you invest discussing this with us "rivet counters".
Still, thanks for all the time you invest discussing this with us "rivet counters".
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I'll dig them out when we get into the detail testing on the armor. Next stage (gawd help us) is banging away with all guns, rounds, angles etc etc. Then we check the theoretical math to make sure that we are getting the result the math predicts. Then we go back and check the resutls we are getting against more subjective data - do these results make "sense" given the test firing data, photographic evidence and battlefield evidence.I was asking for sources on the L/43 with the PzGr.39 repeatedly failing to penetrate the T-34's glacis at any range below 500m.
Still, thanks for all the time you invest discussing this with us "rivet counters".
The trouble in creating an "all-encompassing model" is always the same: the empirical data is very limited (usually interpretations of test-firing data, against one or sometimes two angles). Complicated by the fact that the test firings are usually "match quality" ammo, firing against specific hardness test plate. Even more complicated by the fact that these test firings are actually looking for limit velocities - they are then "interpolated" to give very theoretical penetration data. people forget that the whole mess is derived from probability theory in the first place, so needs to be probabilistic in the model.
But we'll refine as we go, to get it to match the world as we can see it in the data. No, we won't "nerf" the damn things.
Always happy to discuss - I've even been known to change my views and interpretations of the data. I just bored of dealing with gormless little twerps who have nothing constructive to add apart from insults
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Just remember guys, when the game goes live, type "wilsonamgodmode" into the console and all your tanking difficulties will disappear.
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O.k
Firstly the sour one (LemoN) is both correct and incorrect...there fore Alan (Willianson) is also correct and incorrect.
Data shown does not show AOA (angle of attack)...from hits shown from flat plain the APCBC round had a 60/40 chance of penetrating based on where it it hit and at what range (the drivers hatch was always a good target).
This calculation becomes suspect when looking at land gradient, was the T34 going uphill or downhill ATT when hit, which alters the penetrating properties of the round (good luck trying to calculate that).
Secondly...what is an American doing watching a real ball game where the Pads used don't out weight the player...and well done the Irish...Yer a god send and even We can beat You.
Firstly the sour one (LemoN) is both correct and incorrect...there fore Alan (Willianson) is also correct and incorrect.
Data shown does not show AOA (angle of attack)...from hits shown from flat plain the APCBC round had a 60/40 chance of penetrating based on where it it hit and at what range (the drivers hatch was always a good target).
This calculation becomes suspect when looking at land gradient, was the T34 going uphill or downhill ATT when hit, which alters the penetrating properties of the round (good luck trying to calculate that).
Secondly...what is an American doing watching a real ball game where the Pads used don't out weight the player...and well done the Irish...Yer a god send and even We can beat You.
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Just remember guys, when the game goes live, type "wilsonamgodmode" into the console and all your tanking difficulties will disappear.
I'm compiling a list of hidden console commands.
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So it's all good that I remind Him that He did'nt get the Grandslam and Triple Crown (which Wales got twice this Millenium) then
...and will probably suck even though they got the easiest pool in the World Cup Of Rugby Union ... and will He been in NZ come the big games.....
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[OT]Come on Welshie, we all know England have a considerably higher chance of making it further than Wales in the RWC - they always come good for World Cup years...even when they are playing like ****, unlike Wales who since Mike Ruddock left have been thoroughly pedestrian [/OT]
[/OT]
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Actually, Alan is ENGLISH. Not British. Well, officially I am also British and my passport says "European". But I am English. Apart from a teenie bit that is Norman.
As for the Rugby World Cup - after England's fairly dismal win of the Six Nations, I am NOT looking forward to RWC. I think we are (all) in for a major kicking unless we sharpen our game up considerably.
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This whole thread is my kinda RO thread: chatting with the devs about the metallurgical properties of mid-war Soviet forging technology or something while also discussing why the Welsh are pansies. I'm hoping that ROHOS has a "grognard" difficulty where the players all sit around at a table in the middle of a map and trade Excel spreadsheets of penetration values.
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Huh?
Thing is that every single source I've ever read or found put the KwK 40 PzGr.39 from the L/43 at 90-93 @ 30
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One of the errata sheets for Bird&Livingston's book delves into the matter.
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Unless I am wrong, and I am never wrong, ROOST models the F1 grenade fragments (not technically "shrapnel"). This explains the occasional grenade distance kills. The closer you are, the higher the chance you'll be hit by a fragment, the further, the lower the chances, but it can still happen.
I recall Ramm commenting on the famous WWII online tank penetration demo (full spalling and fragments modeled), and he saying it was a bit overboard. So we might not see that level of fidelity, but if the end point results in the same chances of a kill, it should be fine.
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See? I said the data gets messy fast
Penetration of the 75mm L/43 firing Pzgr.39 (range/penetration) as at 30 degrees:
Jentz (Panzertruppen):
100m - 99mm
500m - 91mm
1000m - 81mm
1500m - 72mm
2000m - 63mm
The Royal Armored Corps Tank Museum, Bovington has slightly different figures:
450m (500 yds) - 84mm
900m (1000 yds) - 72mm
1350m (1500 yds) - 62mm
1800m (2000 yds) - 62mm (which is a little wierd)
The Jentz figures are exactly the same as the proof round data quoted in Livingston & Bird. Pretty much agrees with the Datenblatte for the L/48 (which apparently had very similar performance). L&B then apply a formula which gets them up to the 105mm (not 107) for 50% success in the field (I said it was probabilistic). But this assumes that the Soviet armor is as brittle as estimated - which doesn't match with tests done by the Brits on an M42 (in 1943), where the armor plate actually wasn't anything like the hardness (or brittleness) that had been indicated. BHN readings were well below that "very high hardness" set of values (see the relevant British report on the T-34).
But I'd missed that errata (damn them sneaking that in on page 136!). I also haven't (yet) played with the base data to do that calc on producing a "50% success in the field figure". Scarily, that (apparently) small difference makes a huge difference to success or failure. Interesting to note that I thought their high hardness factor was unkind to the Soviets - but mine calculates out as 0.72, compared to their 0.76, so scratch that idea!
We largely agree on the calculation methods - difference right now is that key base figure of the "50% success" figure. Scary how much tweaking that simple figure does.
An area that I can't remember if L&B take into account is the comparison of the hardness of the test firing plate to the actual target. Comments, anyone? Besides, I still have the turret front pretty vulnerable
Edit: and I meant to say - "see where sane and reasoned debate gets you?"
Penetration of the 75mm L/43 firing Pzgr.39 (range/penetration) as at 30 degrees:
Jentz (Panzertruppen):
100m - 99mm
500m - 91mm
1000m - 81mm
1500m - 72mm
2000m - 63mm
The Royal Armored Corps Tank Museum, Bovington has slightly different figures:
450m (500 yds) - 84mm
900m (1000 yds) - 72mm
1350m (1500 yds) - 62mm
1800m (2000 yds) - 62mm (which is a little wierd)
The Jentz figures are exactly the same as the proof round data quoted in Livingston & Bird. Pretty much agrees with the Datenblatte for the L/48 (which apparently had very similar performance). L&B then apply a formula which gets them up to the 105mm (not 107) for 50% success in the field (I said it was probabilistic). But this assumes that the Soviet armor is as brittle as estimated - which doesn't match with tests done by the Brits on an M42 (in 1943), where the armor plate actually wasn't anything like the hardness (or brittleness) that had been indicated. BHN readings were well below that "very high hardness" set of values (see the relevant British report on the T-34).
But I'd missed that errata (damn them sneaking that in on page 136!). I also haven't (yet) played with the base data to do that calc on producing a "50% success in the field figure". Scarily, that (apparently) small difference makes a huge difference to success or failure. Interesting to note that I thought their high hardness factor was unkind to the Soviets - but mine calculates out as 0.72, compared to their 0.76, so scratch that idea!
We largely agree on the calculation methods - difference right now is that key base figure of the "50% success" figure. Scary how much tweaking that simple figure does.
An area that I can't remember if L&B take into account is the comparison of the hardness of the test firing plate to the actual target. Comments, anyone? Besides, I still have the turret front pretty vulnerable
Edit: and I meant to say - "see where sane and reasoned debate gets you?"
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We largely agree on the calculation methods - difference right now is that key base figure of the "50% success" figure. Scary how much tweaking that simple figure does.
Comments, anyone? Besides, I still have the turret front pretty vulnerable
Edit: and I meant to say - "see where sane and reasoned debate gets you?"
As long as there is a chance!
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