AMX-30B2 incorrect number of Gear

CaID · October 19, 2021

# Game version

# Description

The AMX-30B2 as modelled ingame is having the wrong number of gear.

# Steps to reproduce the issue

Lunch a game using the AMX-30B2
drive around and see the gear

# Additional Information

The AMX-30B2 was built with the New Minerva ENC 200 transmission. revealed in 1979 along side the AMX-32 during satory 1979. source indicated clearly in multiple place "Minerva transmission" or "inverting transmission" or "ENC 200" or "5 gear forward and 5 gear backward" those indication are all associated to the Minerva ENC 200 who is a 5-speed inverting transmission.

this have for effect to give the AMX-30B2 identical power to go backward as it can go forward. the speed is them the same in both direction. the ENC 200 have a torque converter ratio of:

1st gear : 4 04:1

2nd gear : 2 33:1

3rd gear : 1 49:1

4th gear : 0 93:1

5th gear : 0 62:2

those gear are all forward, there is no reverse gear as the transmission include an inverse system making those gear been both for forward and reverse.

On the AMX-30B2, source show this speed for each gear.

1st gear : 7 km/h

2nd gear : 15 km/h

3rd gear : 26 km/h

4th gear : 43 km/h

5th gear : 65 km/h

this would give the same speed backward as the transmission is inverting. the backward speed would reach 65 km/h

now did some digging and found the coding who rule the speed in the data of Warthunder. it give this

"mechanics":

{ "maxBrakeForce":

150000.0

,

"driveGearRadius":

0.33

,

"mainGearRatio":

1.0

,

"sideGearRatio":

4.2

,

"neutralGearRatio:

10.0

,

"gearRatios":

[

{ "ratio": -1.101 }

,

{ "ratio": -1.2 }

,

{ "ratio": -1.667 }

,

{ "ratio": -2.6 }

,

{ "ratio": -4.64 }

,

{ "ratio": -6.0 }

,

{ "ratio": 0.0 }

,

{ "ratio": 8.0 }

,

{ "ratio": 6.0 }

,

{ "ratio": 4.64 }

,

{ "ratio": 2.6 }

,

{ "ratio": 1.667 }

,

{ "ratio": 1.2 }

,

{ "ratio": 1.101 }

for those who do not understand the coding, those are the lines of code that rule the gear of the AMX-30B2. this give 7 forward speed and 6 backward speed. thing that i later confirmed ingame and will be show in the screenshot bellow. this make the reverse speed perform somewhere between the 4th and 5th gear, giving a speed around 27-28 km/h in reverse. which is far from the reality

while the AMX-30B2 should infact have 5 forward and 5 backward speed, the 5F/5R would also be incorrect.

the AMX-30B2 is equipped with a Torque converter who allow the Gear to work in a Low and High setting (like a off-road vehicles) which actually double the ratio. as this feature is rather complicated to have ingame, the best way to simulate it would be to double the gear, as each gear have a High and Low version, simply making 10 gear instant of 5 would make it perform just like if there was 5 gear + torque converter in real life. making it simple for the programmer to implement this feature. this would make the AMX-30B2 drive a lot smoother.

after making my own calculation, and made it verified with some of my fallow friends who have notion of the game and programme, i concluded this would be the correct gear

"gearRatios":

[

{ "ratio": -0.62 }

,

{ "ratio": -0.93 }

,

{ "ratio": -1.49 }

,

{ "ratio": -1.55 }

,

{ "ratio": -2.325 }

,

{ "ratio": -2.33 }

,

{ "ratio": -3.725 }

,

{ "ratio": -4.04 }

,

{ "ratio": -5.825 }

,

{ "ratio": -10.0 }

,

{ "ratio": 0.0 }

,

{ "ratio": 10.0 }

,

{ "ratio": 5.825 }

,

{ "ratio": 4.04 }

,

{ "ratio": 3.725 }

,

{ "ratio": 2.33 }

,

{ "ratio": 2.325 }

,

{ "ratio": 1.55 }

,

{ "ratio": 1.49 }

,

{ "ratio": 0.93 }

,

{ "ratio": 0.62 }

this new gear ration would give the AMX-30B2 a 10F/10R who would simulate a 5-speed transmission with a Torque converter. in theory this would give the same speed as reported by Giat for the AMX-32. the developer could copy-paste this line of code and as far i know, it should fix the bug.

# Affected vehicles

AMX-32

# Files

here is screenshot of the testdrive done with the AMX-30B2 stock, doing a straith drive in the paved road who is almost perfectly horizontal and flat. it clearly show the gear and the speed (i suppose the speed would be better if the tank wasn't stock)

Spoiler

Source 1
1. Chars, véhicules chenillés et semi-chenillés
2. Spoiler
Source 2
1. Jane's armour and artillery 2005-2006
2. Spoiler
Source 3
1. Encyclopedie des char de combat modern, tome 1, concerned part highlighted in red with a translation fallowing
2. Spoiler
  
  translation of the part highlighted in red
  
  L'AMX 32 took full advantage of the development made for the modernization of the AMX 30, which led it to the AMX 30B2. in Particular, we can name the Minerva gearbox
Source 4
1. details of the ENC 200, since the tanks are equipped with inverser, the reverse speed are not used.
2. https://www.armyrecognition.com/images/stories/customer/sesm/pdf/ENC_200.pdf
Source 5
1. details of the ENC 200, Jane's AFV Retrofit Systems 1991-1992, this one seem to ignore the reverse gear as the tanks had inverser.
2. Hide contents