20 pounder vs. T54's front hull
 

In the game the 20 pounder's APDS shot has a penetration value of 30. While this is correct for armor sloped at 0 degrees from vertical, it is not the case for its performance vs. sloped armor. The frontal hull of T54/T55 is 20 IIRC, which is it's LOS thickness, but not its actual effective thickness vs. contemporary rounds. The result is that the 20 pounder can kill T54s frontally up to 1800 meters, while in reality it would struggle against the T54's hull armor even at very close ranges.

I think the gun's penetraton values should be corrected, as now it is as effective as the APDS of the L7 gun, the latter of which was made to combat the armor of T55.

Re: 20 pounder vs. T54's front hull
 

Unfortunately WinSPMBT doesn't directly deal with armor slope, it's just factored into the armor value a vehicle is given.

Could it be the frontal armor value of the T54/55 is to low?

Re: 20 pounder vs. T54's front hull
 

T54 turret front is 23 in game terms. Not 20.

30cm at the muzzle, 29 at 500m, 27 at 1000m, etc as shown in the table for it at this site: http://www.wwiivehicles.com/great-br...ion-tables.asp

Running the APCALC utility, it gives 30 at the muzzle for 20pdr 52 (presumably the Mk. 3 APDS), 27 at 500m, 24 at 100m. So its actually a smidgeon under-performing in the game.

Final range bucket where armour pen equals the front turret of t-54 is 1200m. (If defending armour is equal to the pen value, it is not a guaranteed pass-through). Also, on the game map the firer is not always at a 0 degree angle-off, so the effects of the target angle-off will usually reduce basic penetration somewhat.

The 105mm L7 1959 model APDS will do a T-54 front turret to 1500m using APCALC, again in perfect conditions.

The 20 pdr was a very good gun, but had reached its ballistic limits. The 105mm allowed more penetration at a longer range, but the main thing it really brought to the table was a calibre useful for chemical energy munitions (HEAT and HESH).

20 pounder centurions do about evens against T-54s at 1000m and under in the game, but the T-54 tends to plink a few of them back using the 3-5 HEAT shells they carry by the time the up-armoured models arrive. And they can do tat at long range too, which is annoying. Plus centurions are slow, so will often lose any manoeuvre battle against a thinking opponent. If trying to stop a horde of T-5X with Centurion III with the original armour suite, you will lose quite a few..

The data wont be changed. 20pdr APDS was twice as energetic as the WW2 German 88L71 at the muzzle after all. It was rather a hot gun. It is not a wonder-weapon, though.

Re: 20 pounder vs. T54's front hull
 

I only had a quick look for real life stats Which look about right for the gun, did not look up stats for L7 iwhich in game is only marginaly more effective than the 20 pounder.
At your quoted range of 1800m L7s penetration is only +1 on the 20.

Quick look also T54/55 armor looks right the angles already factored into the game stats. Armour was roughly 100 at 60 degrees which is 20 as represented in game.

So yes I would expect the 20 pounder to kill a T54/55 easily at close range, 1800m the oucome will depend on how lucky your die roll was the result could be kill damage or no effect.

Re: 20 pounder vs. T54's front hull
 

Ha phone call means got pipped, front hull is 19 or 20 in game dependant on model which fits RL

Re: 20 pounder vs. T54's front hull
 

Armourcalc is included with the game........10cm @ 60 degrees = 20 and that's what it gets so YES slope IS factored into the equation for all amour values and 305mm is what a 20 pounder APDS could penetrate and in the game that's what the 20 Pounder 52 is rated at....... the 20 Pounder 50 OTOS only gets 24 and at 1000m the sabot pen for the 50 is under the t-55's armour but the "best pen" ( because we toss a host of possible variables in ) is 23 so in some cases it could.

The numbers we have in the game reflect the correct information available ---including armour slope which is always factored into the armour data

That said this LINK gives this data for the 20 pounder
http://forum.shrapnelgames.com/attac...1&d=1471700197

The problem with some of these reported angles @ is they can be reported two ways....90 is verticle so that is also zero inclination..enter 90 into armourcalc and it gives an impossible number so for this it tell me that with perfectly vertical target armour the APDS will penetrate >200 at 1500m but not penetrate at 2000m and APCalc agrees ...it gives 19 pen at 2000 but MAYBE 23

What I wonder is.....we give the 20 pounder tanks nothing but APDS , none I have found carry APCBC but IDK what ammo loadouts for those tanks were ATM------further EDIT..........http://www.lancers.org.au/site/Centurion_Tank.asp........

so sabot and HE only as we have it

and YES..THIS data ( there will ALWAYS be difference is data like this ) claims best pen for the 20 pounder is 285..rounded up it's would be 29 in the game..... IF this data is accurate.. and that one cm difference translates to about 200 m difference in the game.....you get 1700 results at 1900 re : 29 pen vs 30 for "basic" sabot ( not best sabot )


This link http://www.wwiivehicles.com/great-br...ion-tables.asp

for the 20 pounder APDS MK3 at 500 yards = <TABLE class=specificationsTable cellSpacing=0 cellPadding=2 border=1 abp="2477"> <TBODY abp="2478"> <TR abp="2513"> <TD abp="2518"></TD> <TD abp="2520">11.61"<SUP class=sources abp="2521"></SUP></TD></TR></TBODY></TABLE>

that's 29.4894 CM
<SUP></SUP>
Don

Re: 20 pounder vs. T54's front hull
 

As i said, I know that 20 pounder can penetrate a bit over 300mm of RHA without slope. The problem lies in that its performance drops a lot against sloped armor (especially against highly sloped armor like the T54s front hull), so no, a simple x/cosθ will not give the effective armor thickness of the target. The only rounds that follow the above simple equation relatively close are HEAT rounds, but none of the KE rounds do(modern APFSDS are better in this and some like DU penetrators are actually better against sloped armor than vs thick unsloped one, hence the boxy design of modern MBTs). Anyway, in KE rounds, things like thickness/diameter ratio, armor quality projectile speed etc give very different results that vary from round to round and in the case of APDS rounds a slab of armor of 100mm RHA sloped at 60 degrees from vertical has 3.5 effectiveness against the incoming round, which makes the T54s hull a very hard nut to crack even at point blank range (source: WW2 ballistics armor and gunnery by Lorrin R. Bird and Robert D. Livingston pages 30-31, although it speaks mainly about 17 pounder, 20 pounder wasnt much different).

Btw DRG the link you gave is from warthunder and after many updates this games handles sloped armor differently. 20 pounder now penetrates 80mm @60 from vertical, compared to the 100mm @60 needed to defeat the T54's front hull.

Re: 20 pounder vs. T54's front hull
 

Oh, and here's another link that mentions what I've said: http://www.dtic.mil/dtic/tr/fulltext/u2/a954868.pdf

On page 6 it says: "Since the HEAT shell does follow the cosine law, a round which can penetrate a 12 inch plate at normal obliquity, can defeat a 6 inch plate inclined at 60deg obliquity. For comparison, the 90mm HVAP M304 shot can defeat 12 inch plate at 0deg obliquity, at ranges up to approximately 1300 yards, but cannot defeat even 4 inch thick plate at 60deg obliquity when fired at point blank range."

Unfortunately, finding a link like that for 20 pounder ammunition is proving extremely difficult. Nonetheless, I do believe that 20 pounder will have trouble defeating T54 hull armor above 400 meters at best.

Re: 20 pounder vs. T54's front hull
 

This is a rather good read on physics of kinetic energy projectiles:
http://ciar.org/shotmagnet/Armor%20a...rojectiles.pdf

However, they're testing modern, 105-140 mm KE penetrators. Old ammunition might have been worse and glanced off or broken easier by slanted armor.

I could try and find if there's any material in Finnish related to this gun. Finns have a tendency of keeping all the records somewhere and then unclassifying them. However, I suspect that the issue of slanted armor effectiveness from gun to gun will provide way too complex for the game and this will be mostly an academic exercise.

Re: 20 pounder vs. T54's front hull
 

[quote=Aeraaa;835053]"(source: WW2 ballistics armor and gunnery by Lorrin R. Bird and Robert D. Livingston pages 30-31, although it speaks mainly about 17 pounder, 20 pounder wasnt much different)."

A late model 17 pdr fired APDS at 1,204 mps. (3,950 ftps) giving 275 mm of penetration at 100 mts and 162 mm of penetration at 3,000 mts.

The 20 pdr fired APDS at 1,465 mps (4,810 ftps) giving penetration of 300mm at 100 mts and about 195mm at 3,000 mts.

(Worth noting that the 20 pdr APDS round had roughly twice the penetration of a German 88mm AP round).

So far as I'm aware most armour penetration tables work on the basis of a 50% chance of penetration of a given thickness of armour at a given range ( but I was never a Tanker).

Re: 20 pounder vs. T54's front hull
 

Every army (and navy) had different criteria to determine what was considered as "penetration". It could range from the tip just cracking the back of the plate through to 100% chance of it passing fully through. Some may require the projectile to both pass through and penetrate a certain thickness "witness plate" a certain distance behind the test plate as well (I.e. have some useful remaining energy post penetration).

So you need to know what particular test criteria was used for any given figures. Same goes for angle - some used 0 degrees as vertical, some used 0 as horizontal. Also, what was the target plate (RHA, Harvey steel, wrought iron etc). And was the penetration an average of several hits, or the best (or least) of several firings.

Loads and loads of variables. There is no one "true figure" for the penetration of anything really!.

We use the system SSI used for the original game, and that wont be changing.

Re: 20 pounder vs. T54's front hull
 

The best option for the game as it is now is IMHO to increase tank toughness for tanks fighting in early Cold War. Late 40ies-early 50ies tank toughness should be 140 for Russian vehicles, 120 for NATO ones (due to Russians using shells that work a bit better against slopes). Late 50ies-early 60ies Russian tank toughness 120, NATO same (the introduction of L7). After that, tank toughness 100 for both (APFSDS and HEAT rounds have very little degradation by sloped armor). Now my suggestion isn't without flaws, namely the fact that turrets become tougher than they should be and HEAT rounds are also affected when they shouldn't. About that I do have a request to make for a future update. How possible is it to include another option in the preferences screen, something like "HEAT tank toughness" that would be different than regular tank toughness? By fine fine tuning that we can make a better approximate of the probably behavior of tank armor vs every shell of the era.

Re: 20 pounder vs. T54's front hull
 

Andy is absolutely correct, the variables in testing penetration levels and or protection against penetration are numerous and would drive the ordinary person "nuts" with mind bending overwhelming data with which I would be happy to provide to make the point, however, I believe one or two people out here would rather I didn't knowing my penchant for data collection going back to the ERA issue we had out here a year or two ago.

I can say all the usual things "We do the best we can." We have game limitations" "We will never really know all the true data results." etc. etc.

And unfortunately we'll never satisfy every developer, campaign/or scenario designer or player it just won't happen. We're from different countries, cultures, sexes and personal backgrounds/life experiences and up bringing. But that doesn't matter as we welcome everyone that comes along-regardless.

What we have all in common is generally we love to play wargames and to a lesser degree many of us have/had a military background. Some I suspect even had actual game design backgrounds either professionally or in consulting.

So my point takes me back to my Middle School/High School years to probably the most advanced game of it's time related somewhat to our current game(s). This game is the one that got me in my "research mode" as it had around 50 or so blank counters to update equipment with or add new ones, like most all games from this company had at the time using the existing counters as a rough baselines.

What's important is the issues were about the same to vary degrees the game would be designed by one of the best in the industry at the time. The year is 1972 and I'll start with a direct quote from the designer...

"The reason for this rather negative attitude lies in the fact that tactical games are extremely difficult to design with a large degree of realism. This was readily apparent while designing PanzerBlitz. We went through a good half dozen approaches. The one we finally arrived at was not, in our opinion, the best one. In other words, the research and development on tactical game designs could not stop with PanzerBlitz...The Tac3 approach was ultimately a blind alley. It could really go nowhere. In order to add any more realism to a game using this approach required enormous sacrifices in playability. A breakthrough, we feel, came with the development of a workable simultaneous movement system.

...The most important thing needed for the redesign of Red Star/White Star is the use of a simultaneous movement system...Of course...we could not merely be 'adding' simultaneous movement. Many other changes will be made also. This is, of course, because no game is ever finished as far as its design goes. Not only does the state of the art change and improve, but the historical data becomes more abundant, more insightful, and more useful, the longer the game is out. A game, after all, is a research tool...4"

Now I can really relate to those last couple of sentences. It almost even sounds like me-scary! :D

So there you have it SPI's Red Star/White Star the lessons from 1972 are essentially the same as we're dealing with 44 years later with our games the challenges remain the same and the hard work continues.

I hope you'll take the time to read the following it's worth the perspective it might hopefully give and reading the previous posts my mind immediately jumped back to this game of my youth.
http://tacticalwargamer.com/boardgam...rwhitestar.htm

For further insight you could go back to my first wargame and still one of my favorites for ease of play and just plain fun!
http://tacticalwargamer.com/boardgam...z/tacgame3.htm

Regards,
Pat
:capt:

Re: 20 pounder vs. T54's front hull
 

This also points out one of the great strengths of the WinWW2/WinSPMBT games, they are user modifiable. If for whatever reason you don't agree with or like the default weapons/units/formations/game settings you can change them to your hearts desire.

When I first discovered the game I was thrilled, and disappointed. While the weapons represented in the USMC OOB were accurate (or at least game standard) and most of the units were pretty darn close (tho a few left me scratching my head) the formations were a complete mess (excuse me Andy/Don). It was obvious someone looked at the paper TO&Es and assumed that like most military organizations the TO&E represented the combat organizations used. Unfortunately the USMC is one of the odder ducks in the pond.

So as a personal project I rebuilt the OOB (not including picklists because at the time I had no clue how they worked) and decided to put my PERSONAL OOB up on these forums for anyone else that wished to to use. With the standard, and necessary, disclaimer that they were not official. One thing led to another and now it is. But it was not because my alterations had any effect on basic game mechanics (and probably because they didn't). Those are, and should be, the perview of Andy and Don alone because only they have intimate knowledge of, and access to, the game code.

Yes, the game tends to incorporate accurate representations of real-life equipment capabilities/stats when possible. But as has been stated conflicting data is the norm not the exception. And there are as many personal interpretations of this data as there are people looking at it. Some people, for various personal/professional reasons, are use to dealing with this sort of thing.

But that is totally irrelevant. Andy and Don are the guys behind the game, if for whatever reason they disagree with, or feel something is to difficult to implement (in the ancient and not terribly well written/documented game code) it won't be, no matter how much data we present them.

Feel free to present whatever you wish here, and to make a personal version of any OOB(s) you want and post it. Hell, the game encourages that! But once the official foot has come down (and Don has stomped me into the dirt repeatedly over aircraft issues) don't beat a dead horse.

One thing many people proposing alterations to game mechanics often fail to appreciate is WinSPMBT is first and foremost a game not a simulation.

Re: 20 pounder vs. T54's front hull
 

Necro'ed the thread because there are two more interesting simulations below:

https://www.youtube.com/watch?v=vporVkAUvbM

https://www.youtube.com/watch?v=EBPWS3WJ1b4&t=7s



And it confirms my assumption about how tough T54's hull really was vs. early Cold War projectiles (if anything I was proably too lenient on the 20 pounder). T-54 can easily kill early Centurions, although the Mk5 onwards should be way tougher and need HEAT ammunition.