Supergabry

P40 L34 Main Gun Entry and Penetration is In Error...

According to all the sources i can find on the internet the 75/34 cannon mounted on the P40 had 90mm of armor penetration at 100m with an impact angle of 0°, why in game the gun penetrates only 75mm of armor at its best? The projectile weights a bit less than the Sherman APHE round and it's a bit faster, but the M4 can penetrate 90mm of armor, why is it that way?

Currently in game the P.40 has a 75/32 shell that isn't a 75/32, but a 75/27AP.

The second round was lighter and was used in 75/18 guns of Semovente 75/18, the 75/34 that equipped the P.40 had a different shell, the 75/32 AP.

 

I think the penetration for the P.40 is calculated using the Krupp table (I tried making the math and it's correct), but instead of the weight of 8.59Kg (75/34) using the 6.2Kg (75/27), the current in game round also has the same filling of the 75/27, confirming my theory. 

 

To sum up: the 75/32 AP round of the P.40 should have 90mm of penetration at 5m, and probably a different filler, the current round is a 75/27.

 

I got the data from an US Army document called "Italian and French Explosive Ordinance", here is the page with the 2 rounds.

 

Can the developer team fix this issue? Should I post this somewhere else?

8yv77u2_zps3125259b.png

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Please post this in the Moderated bug reports.

https://forum.warthunder.com/index.php?/forum/590-flight-and-damage-model-issues/

Here are the guidelines for posting this:

If you have any questions about this or filing the report, please message a technical moderator.

Bugs/Suggestions/Technical Problems
(Technical Moderators):

 

Bugs/Suggestions/Technical Problems
(Senior Technical Moderators):

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14 hours ago, Supergabry said:

According to all the sources i can find on the internet the 75/34 cannon mounted on the P40 had 90mm of armor penetration at 100m with an impact angle of 0°, why in game the gun penetrates only 75mm of armor at its best? The projectile weights a bit less than the Sherman APHE round and it's a bit faster, but the M4 can penetrate 90mm of armor, why is it that way?

Currently in game the P.40 has a 75/32 shell that isn't a 75/32, but a 75/27AP.

The second round was lighter and was used in 75/18 guns of Semovente 75/18, the 75/34 that equipped the P.40 had a different shell, the 75/32 AP.

 

I think the penetration for the P.40 is calculated using the Krupp table (I tried making the math and it's correct), but instead of the weight of 8.59Kg (75/34) using the 6.2Kg (75/27), the current in game round also has the same filling of the 75/27, confirming my theory. 

 

To sum up: the 75/32 AP round of the P.40 should have 90mm of penetration at 5m, and probably a different filler, the current round is a 75/27.

 

I got the data from an US Army document called "Italian and French Explosive Ordinance", here is the page with the 2 rounds.

 

Can the developer team fix this issue? Should I post this somewhere else?

8yv77u2_zps3125259b.png

Yes, the actual main cannon is not definitive, the work is in progress to determine the exactly performance wich was better.

Edited by Redberseker

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21 hours ago, MasterofBlitz said:

Please post this in the Moderated bug reports.

https://forum.warthunder.com/index.php?/forum/590-flight-and-damage-model-issues/

Here are the guidelines for posting this:

If you have any questions about this or filing the report, please message a technical moderator.

Bugs/Suggestions/Technical Problems
(Technical Moderators):

 

Bugs/Suggestions/Technical Problems
(Senior Technical Moderators):

Thank you sir

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Did you post it in the bugs subforum? I can't seem to find it. 

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On 16/11/2017 at 12:44 AM, MasterofBlitz said:

Please post this in the Moderated bug reports.

https://forum.warthunder.com/index.php?/forum/590-flight-and-damage-model-issues/

Here are the guidelines for posting this:

If you have any questions about this or filing the report, please message a technical moderator.

Bugs/Suggestions/Technical Problems
(Technical Moderators):

 

Bugs/Suggestions/Technical Problems
(Senior Technical Moderators):

My post is still pending approval, is it normal?

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Sometimes they take their time in my experience. Maybe wait until the start of next week before investigating further.  

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On 17/11/2017 at 5:24 PM, Supergabry said:

My post is still pending approval, is it normal?

Private message (PM) a technical moderator if you want to check on the thread. Make sure it follows the normal guidelines for filing a report.

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Sill nothing on this?

 

Would be nice for the P40 to get its correct shells and the Effeto Pronto shell. Here is a link to a chart that shows the different rounds and what their calculated penetration values where at 100 Meters against a flat 90 degree plate. I am not sure how accurate the website is (being a gaming website) but the values seem to match up nicely with what was on the former data sheets for Italian shells.

 

Link: http://www.miniatures.de/anti-tank-weapons-italian.html

 

Also, anyone know when we will gain access to the data sheets again? They had a lot of information that I liked to use when researching Italian tanks.

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14 hours ago, CarcanoM38 said:

Also, anyone know when we will gain access to the data sheets again? They had a lot of information that I liked to use when researching Italian tanks.

Ehh good question...

I think they will be available again with the release of the tech tree.

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I am still waiting for my post to be approved, it's been 2 weeks now, I asked a mod he said to not worry, but here we are still waiting...

On 11/25/2017 at 12:14 AM, CarcanoM38 said:

Sill nothing on this?

 

Would be nice for the P40 to get its correct shells and the Effeto Pronto shell. Here is a link to a chart that shows the different rounds and what their calculated penetration values where at 100 Meters against a flat 90 degree plate. I am not sure how accurate the website is (being a gaming website) but the values seem to match up nicely with what was on the former data sheets for Italian shells.

 

Link: http://www.miniatures.de/anti-tank-weapons-italian.html

 

Also, anyone know when we will gain access to the data sheets again? They had a lot of information that I liked to use when researching Italian tanks.

I fear many those data aren't correct, better finding more first hand sources.

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13 minutes ago, Supergabry said:

I fear many those data aren't correct, better finding more first hand sources.

Yep. Some descriptions are wrong too.

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34 minutes ago, _Condottiero_ said:

What about EPS? Shouldn't it have 120 mm of penetration? 

No

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Still nothing? Why is that?

It has already been confirmed that the shells being used in-game are the wrong ones, I don't think there's any doubt about it, so why is it taking so long?

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On 12/4/2017 at 11:33 AM, Leeb_ said:

Still nothing? Why is that?

It has already been confirmed that the shells being used in-game are the wrong ones, I don't think there's any doubt about it, so why is it taking so long?

 

Welcome to how we've felt with the British tanks for a long time now. :P (Also the US ones)

 

Cynical dismissive statement aside, the usual line is that it "takes time" to investigate. The reality is probably more that they just consider it a low priority thing. Whether some people feel that anything Russian would have a naturally higher priority due to the "home" playerbase priority is an entire other area of subjectivity.

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Now i could be wrong so don't take this as fact but i believe that they will fix the pen when the full Italian tech tree is out

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8 minutes ago, Detective_Pardo said:

Now i could be wrong so don't take this as fact but i believe that they will fix the pen when the full Italian tech tree is out

 

I was thinking about that, too...

But if that is so, that'd be a very dumb move on Gaijin's part, as people are less likely to buy it with its current pen.

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2 hours ago, Detective_Pardo said:

Now i could be wrong so don't take this as fact but i believe that they will fix the pen when the full Italian tech tree is out

I hope it too...

Edited by Menarrosto
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Heard anything yet? I'm assuming you'll let us know when something comes up.

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On 27/12/2017 at 12:04 PM, Vand3rz said:

Heard anything yet? I'm assuming you'll let us know when something comes up.

The bug report has been cancelled, because 8.59kg is the weight of the round

We have to look at the "weight of the projectile", which unfortunately is missing in the document.

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On 14/01/2018 at 04:28, Cpl_Stalinium said:

The bug report has been cancelled, because 8.59kg is the weight of the round

We have to look at the "weight of the projectile", which unfortunately is missing in the document.

 

I don't think it is the round. I think it is the gun.

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Here is the advertised statement of the P40 main gun as in the advertising section: "The development of the P40 medium tank started in Italy in the early forties. The performance of the P40 was, at the time of its introduction, quite comparable to later modifications of the German Panzer IV. The P40 was equipped with a 75mm anti-tank cannon, capable of penetrating 70mm of armour at a range of 500 meters, as well as a Breda 8mm coaxial machine gun. As thankfully the relatively thin armour isn’t weighing the P40 down too much, the 330 horsepower diesel engine is entirely capable of getting the vehicle up to its maximum speed of 40 km/h in a relatively short time. As such, the P40 can keep up with the advance of lighter vehicles and effectively support them throughout the battle."

 

Now, in the Wiki, the P40 (really we should call it P26/40, but we know that), the main gun is written as a 75mm L/34 main gun.

 

But in reality, the weapon being used is this: The Cannone da 75/32 modello 37. Link: https://en.wikipedia.org/wiki/Cannone_da_75/32_modello_37

 

-

 

Background: The P26/40 went through three iterations in its prototype stage. At first, a smaller design was equipped with the Semovente da 75/18's howitzer. Secondly, it was equipped with the cannone da 75/32 modello 37, as shown in the link. However, referencing the Wikipedia source for the cannone de 75/34 at the bottom of the page shows that this goes back to the original 75/32's performance stats instead.

 

But those are just the first two iterations of the P40!!! The final prototype was given the cannone da 75/34. That is this model that was sent into production.

 

When we look at the 75mm L32 Wikipedia entry, we encounter the muzzle velocity given on the War Thunder Wiki: 624 meters/second. The gunnery table and that of the  includes the title "Granata Perforante 75/32", and on down the line, which results in the confusion. Yet in the Wikipedia source for the P26/40, we encounter this dialogue concerning the third and final prototype which was then ordered to be mass produced: "The main weapon was the 75/34 gun, a development of the Model 37 divisional gun (34 calibres long), retaining the same dimensions. This weapon had a muzzle velocity of around 700 m/s (2,300 ft/s); and was normally provided with around 75 rounds of ammunition. Its armour-piercing shells could penetrate roughly 70 mm of armour at 500 meters." Link: https://en.wikipedia.org/wiki/Carro_Armato_P_40

 

-

 

In short, the 75mm cannon being used is not the L/34 cannon that is 34 calibers long with 700 meters/second muzzle velocity, but the second prototype using the 75mm L/32 (32 calibers long) as a fill-in and the much lower average muzzle velocity of 624 meters/second.

 

I strongly request that this be brought to the attention of the Wiki editors and the development team.

 

There was an attempt to bug report this earlier as an issue with the ammunition, but I don't think it has anything to do with the ammunition itself. Or a better way of putting it would be that the wrong ammunition was coded in.

 

If this is the second prototype's L/32 main gun that we are working with, I'd appreciate it personally if this be brought to the Wiki team's advisement and the situation corrected and the statement clarified that that is what we purchased.

 

However, if it was the intent of using the final prototype with the L/34 main gun, than the APCBC and HEAT rounds should be re-coded for their proper muzzle velocity at 700 meters/second and their appropriate penetration values.

 

Thank you.

Edited by WHISPER_Two

BlueBeta (Posted )

Discussion merged to existing one
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The only prototype with sloped armour was the final one with the 75/34. Only the one with flat armour has the 75/32.

I suggest you start collecting links if you want it changed.

https://books.google.it/books?id=Afg-DwAAQBAJ&pg=PT11&lpg=PT11&dq=75/34+cannon&source=bl&ots=THStYJtoJm&sig=R8jhK_3x7ZP48MqJy-_cj95Qj6A&hl=it&sa=X&ved=2ahUKEwjOv5b32_HbAhWEiiwKHb-WBcIQ6AEwEHoECAUQAQ#v=onepage&q=75%2F34 cannon&f=false

Edited by SergenteA

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