It’s a purely empirical formula. It’s meant only to interpolate the data, not to be used to explain or extrapolate.
And you can see how well it does it job from comparing it’s predictions to results from the document I posted.
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I’ve put onto a spreadsheet the data on 30° performance of the US 76mm and 90mm HVAP shells located in that document.
As you can see there is a significant spread of results. After eliminating some of data points related on unrealistic situations (like the 5in. plate of 338 BHN) and others that deviated far too much from the average to be of use, it resulted in this data set.
This is the best that can be done.
Using this model, I applied it to estimate the performance of some well known subcaliber shells, as a sanity check:
Edit: Fixed the 5cm APCR graph.
Because in the data set there was no data on performance of these early tungsten carbide cores for velocities above approx. 3200fps, I’ve shown the extrapolated values with a dotted line.
Edit: As a side note, the german 5cm APCR is scary. If this game used it’s real life performance, the Pz.III’s would be 4.0 material, lol.
Interesting.
Tho where did you get 1135m/s for the Pzgr.40/1?
And by Russian, british and USA testing for the 40 it even got to 1200m/s, how would it then perform?
German firing table.
From here: Pak 38 Pzgr.40 and 40/1 - Axis History Forum
Like I said last time, ( I remember our previous conversation on this topic), the earlier 5cm Pzgr.40 (without a suffix) was lighter and had higher muzzle velocity, nominally 1180m/s, but could be anywhere between 1150-1200m/s, depending on the wear on the gun.
While the later one, Pzgr. 40/1, was heavier and had lower m.v., but better ballistics.
Thats not readable? And i dont see a 5 at the back?
Im not doubting the velocitys and i know of both 1180 and 1200, but i was more interested in the 1135 instead of 1130 from in game.
From the looks of it, the Pzgr. 40/1 would outperform the Pzgr. 39 at any range 🤔
But maybe I’m just imagining things.
In the ammo manual it says it should only be used till 800m.
Even though I feel like that German manuals generally underestimate the performance difference at range.
But I guess the difference isn’t big enough to be worthwhile.
Honestly I don’t remember anymore why exactly I use 1135m/s figure, it was just there in my external ballistic calculator. It might be because I once saw a figure of 3725fps (1135.38m/s) in some allied intelligence report on this gun, but I can’t find it now.
But these are really tiny details that are virtually negligible in the grand scheme of things. More importantly, I believe that this historical german FT is quite simply wrong.
The drag on this shell is simply too high, pretty much same as that on the “H”-type arrowhead design of the earlier shell. In the graph I posted earlier I’ve used external ballistics of M93 HVAP, since it has almost identical external shape to the 5cm Pzgr.40/1.
If we were to trust the german FT, the newer APCR shell would have lower penetration than the older one, up to 500m, and only a tiny advantage (5mm at most) at longer range. I don’t believe that germans would change it’s design just for this.
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Idk, the ballistic table says the Pzgr. 40 should only be used till 600m, the Pzgr. 40/1 only to 800m.
So the difference is infact not outstanding.
Yeah, but with many caveats:
- First, only for angles between 0 and 30°.
- It would require the use of tungsten carbide, a rare strategic material.
- Firing hypervelocity shells like these heavily accelerates the wear of the gun.
- The 75mm gun would have a much better HE shell. Like, by a lot. The difference between 75mm and 88mm or even 105mm is much lower (percentage-wise) than between 50mm and 75mm HE.
Thanks for a better quality scan.
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If we compare the estimates for M93 HVAP with the chart we find in “Terminal Ballistics Vol.III” ,we will see this:
The two curves are surprisingly close, especially considering the fact that ballistic limits in ADA301343 were compiled using Army Limit.
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HVAP was nerfed for simple reason …Kugel & 341
I keep getting surprised by how many issues in this game are originating from the unnatural design of the battlespace.
If the vehicles were not forced to fight at point blanc ranges due to cap circles located in small towns, the SPAA vehicles with fast firing small caliber guns would be not be competitive with medium/heavy tanks, with or without subcaliber shells.
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Thing is that they have massive maps that could be used by MBT’s ,modern and old and WWII heavies.
Maps that could with very little work be put in game …i’m talking about Air Maps …if you ever get time load custom air battle ,use reserve plane and land on any air map outside of airfield …you will see what i’m talking about very quickly.
These maps were in game way back in 2012
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The Flakpanzer 341 never even had the H-Pzgr in game, it would be nice if it would finally get it tho.
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They were going to add it ,i think it was noodle that provided documents and instead they nerfed it then buffed .50 call to star trek levels
Thought it would be interesting to take a look at a very exotic sub-caliber shell: 37mm APCNR and compare it’s performance with and w/o the LittleJohn adapter mounted on the barrel:
Even if Gaijin were to introduce it without implementing the mechanics of mounting on and taking off the barrel attachment during battle, it would still be good enough to allow M5 light to take out the menace of low tiers, the dreaded StuH 42 from the front at 300-600m.
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I’m still waiting for them to fix the APCR penetration of the Marder’s 20mm cannon and etc. I’ve already suffered a world with the Marder thanks to the almost useless cannon and the Milan ATGM, which is by far the worst missile in the game. And now, curiously, I’m playing with the Ratel 20 haha, it’s a real vehicle sufficiency.
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But would it be able to reach 3600fps without the adopter? 🤔
I always imagined the adopter rasing the pressure to accelerate the projectile.
But I guess 37mm APCR also can reach that speed, so probably not necessary.
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