revisiting PUMA IFV AHEAD munition

[DownloadPizza 8]

# Game version

My game version: (2.23.0.82)

# Description

Even after introducing the FCS for both BMP2M and PUMA IFV the AHEAD munition does not have its fuse set automatically.

# Steps to reproduce the issue

1. Take PMC308 (from here on out referred to as AHEAD)
2. Track a plane with the IR tracker, this shows a leading point based on the planes distance, speed and current shells muzzle velocity.
3. Fire PMC308, IRL the Fuze would be correctly set to the computed point from step 2.
4. Observe: the shell explodes either not at all (fuze not set) or at the point found by the laser rangefinder by pointing at a spot and pressing the rangefind keybind.

 

 

# Affected vehicles

 

• PUMA

# Files

(shell explodes at 82 meters even if a target is being tracked by the IR FCS)

 

# Sources

 

Sources should comply with the requirements.

1. Video by WELT demonstrating the system in action (time: 35:12)

    

2. Source 2

   1. http://www.army-guide.com/eng/product3067.html

   2. > The projectile of the ABM contains an electronic timer module, which is programmed inductively at the muzzle with compensation for variations in projectile velocity to ensure precise down-range payload release.

3. Not quite a source, in this thread a TM has reasoned that PMC308 can not work since FCS is not implemented. That line of reasoning is now outdated since that is no longer the case. Also one of the sources above is taken from here:

[DELTACLUSTER 1,734]

My game version: (2.23.0.82)

 

The AHEAD ammuniction (PMC308) of the PUMA is currently not performing as a kinetic, pre impact desintegrating round, but rather as a burst HE projectile. This is improperly modeled, as the AHEAD ammunition is purely kinetic in its design and consists of a main projectile that carries subcaliber projectiles in its body. The round is essentially unusable, as the functionality of the AHEAD principle was modeled, but no dispersion of kinetic projectiles. Therefore, the AHEAD round explodes in front of a target, meaning it desintegrates, leaving little shrapnel behind and having no effect. In testing, the round cannot even penetrate the ZSU-23-4, when it has been disabled and the correct standoff is achieved by lasing the target. 

 

This is an incorrect model of the functionality as the main round does not desintegrate by an explosion but rather by ejecting the subcaliber projectiles from the main projectile. Both keep travelling on the same path with the subcaliber rounds increasing their distance from the main round the further they travel after the programed ejection. If modeled accurately the round will eject the subcaliber projectiles at 1-5 meters in front of the target, have its main kinetic warhead travelling continuously along the path with the ejected subcaliber rounds while the smaller projectiles increase their radius traveling from the main round the longer they travel (exact values are provided in the document attached). This means a kinetic penetration in the shape of a main round hit in the center and multiple smaller hits caused by the subcaliber ammunition.

 

The second issue is caused by the rangefinding process in War Thunder. Currently, the rangefinder sets a fixed distance that the rounds explode after. This leads to a complete unusablity when attacking aircraft, helicopters or drones, because the distance will by incorrect by the time the round reaches the airplane and thus will detonate before or after. This is an incorrect model of the real process, during which the gun computer calculates the correct ejection distance based on the tracking of the flying target and the muzzle velocity inside the barrel while firing the round and programming it accordingly. Input by the operator (human) is only done by selecting the standoff distance as described in the documentation attached. This means that the player in War Thunder should be capable of locking the plane, drone or helicopter and use the PCM308 to achieve the effect as the gun computer works out the correct standoff according to the flight path. The standoff distance could either be fixed or relpaced by the rangefinder button, cycling through fixed distances (like 1,5,10,20,30,40m).

For ground use, the player should simply be required to laze the target to activate a fixed standoff distance (suggested is 1m) or no standoff at all. This should mean either a penetration of multiple shrapnel and the main caliber when standoff ejection was used or a penetration and then a release of shrapnel after penetration when no distance was used. This post penetration effect is also described in the document.

It is suggested to develop this functionality as further modern vehicles of the 30mm and 35mm caliber in the german tree may be capable of using the ammunition (in particular AA defense systems), creating the requiremend as well. This is made more severe by the fact that the ammunition is currently essentially non-viable as it does not cause any damage when using it accordingly with the standoff distance by rangefinding to static vehicles or preemtively elminates the chances of a hit by the incorrect self destruction. 
 

Steps to reproduce the issue:

 

1. Launch a test drive with the PUMA.

2. Disable the tracks of the ZSU-23-4.

3. When it is standing still, laze the target using PCM308 and fire at the Shilka.

4. As noted, the ammunition will explode, causing zero damage to the vehicle behind it.

5. Search for a plane flying across the sky.

6. Laze the plane

7. Fire at the plane

8. The result will either be the round hitting the plane directly and damaging it, passing it exploding behind or exploding in front of it. It does not achieve the shrapnel effect of the round.

 

Affected vehicles:

• PUMA

Files:

 

• Screenshot of the pre-detonating round in front of the ZSU-23-4. As seen by the lack of a damage camera, no damage is done to the machine. Taken after 5 consecutive shots with no pause.

•  

  Spoiler

  

   

Sources:

 

1. Source 1: Oerlikon_Ahead_Air_Burst_Ammunition_PBR_EN_B038e0222.pdf

   1. Author: Rheinmetall

   2. The entire source is provided as PDF, coming from the official site of Rheinmetall. Cover and excerpts are found in there.

   3. The relevant page numbers are 2-5.

   4. The correct caliber (30mm) is specified on page 2 in the 2nd block of text: "Its operating principle has been successfully implemented in two calibres (35mm x 228 and 30mm x 173)"

Edited January 30, 2023 by DELTACLUSTER

[David Bowie 1,554]

Hello!

Thank you for your interest and help improving the game.

 

Your information has been forwarded to the Developers for their consideration.

 

If there is anything further regarding this report a Technical Moderator will contact you.

 

Thank you again for your support.