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AMX-30B Obus G Shell (Brainstorm/Proposal)

AMX-30B HEAT Obus G

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Draco90 #1 Posted 07 May 2019 - 04:18 PM

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Hello everyone! Hi again for some brainstorm and/or feature proposal (that i am aware from the start it will never even read from devs).

I just like talking about (but i post in this section, because, you never know...).

(citation: http://bit.ly/304dZco)

One thing i always loved about the AMX-30B is the genius idea of his shell: the Obus G.

In that era, given the fact that almost all round fired by a tank were HEATs (like nowadays in WoT, lol), frenchmen came with an idea on how use a HEAT round in a rifled barrel: that was originaly a problem, as the rotation used for the stabilization diminuished the effect of the HEAT by 10-20%. So they invented a "matrioska" shell, with bearings for keeping the high speed rotation in the outer piece of the shell, while the inner piece is more or less stable, keeping the penetrating power of the HEAT. This shell is called Obus G.

Photo: 

 

 

 

 

 

 

 

 

 

 

 

 

Given this were a special feature of the AMX-30B tank, i would like to see that implemented in WoT.

my idea is to give the AMX-30B a standard HEAT round, with 280 pen (yea, you hear me right) and 330 alpha with a reload of 6.33 sec (keeping the DPM as it is now). Prem round would be AP with 390 alpha and 250 pen. 

Its a little bit weird, and i even completely like it, but its 2 days i'm thinking about it. I think the historical relevance of this type of round could be implemented, using a HEAT base round with high pen. But i dont find a way to balance it.

Would do you think?



Nishi_Kinuyo #2 Posted 07 May 2019 - 04:55 PM

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Except that standard shells always have less penetration than special shells (barring HESH).

So no, not going to fly.

Just accept the buffs that they're already planning for the 30B, including 264mm APCP pen and 330 HEAT.


Edited by Nishi_Kinuyo, 07 May 2019 - 04:55 PM.


WoT_RU_Doing #3 Posted 07 May 2019 - 05:06 PM

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Well for one thing it rather depends on how they model the dynamics for a HEAT shell....if the model includes the dispersion of the HEAT plasma, and the rifling induced spin of the shell, then what you are actually asking the developers to do is put effort into developing a new shell type that has a central non-spinning core, and to program the associated physics specifically for that. As such, it's potentially a whole new mechanic, for a benefit that almost no-one in the game will realise is there, let alone care about. 



4nt #4 Posted 08 May 2019 - 05:29 AM

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Didn't Obus G actually have 400mm nominal penetration, first HEAT with that kind of pen capability? ;)

Draco90 #5 Posted 08 May 2019 - 08:06 AM

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View PostNishi_Kinuyo, on 07 May 2019 - 04:55 PM, said:

Except that standard shells always have less penetration than special shells (barring HESH).

So no, not going to fly.

Just accept the buffs that they're already planning for the 30B, including 264mm APCP pen and 330 HEAT.

Actually SU-100Y has prem shells with less pen and more dmg ;) anyway i am aware of med rebalancing. I'm just wanderimg "if we want to give the 30B some of the historic relevance, what we could do?"

View PostWoT_RU_Doing, on 07 May 2019 - 05:06 PM, said:

Well for one thing it rather depends on how they model the dynamics for a HEAT shell....if the model includes the dispersion of the HEAT plasma, and the rifling induced spin of the shell, then what you are actually asking the developers to do is put effort into developing a new shell type that has a central non-spinning core, and to program the associated physics specifically for that. As such, it's potentially a whole new mechanic, for a benefit that almost no-one in the game will realise is there, let alone care about. 

Yea, but as stated on the answer before, i'm just thinking how It could be introduced and balanced a obus g Shell on 30B, given that was a special feature of that tank, as were (and are) HESH shells on UK tanks. 

View Post4nt, on 08 May 2019 - 05:29 AM, said:

Didn't Obus G actually have 400mm nominal penetration, first HEAT with that kind of pen capability? ;)

Indeed. But giving 400mm of pen on a med tank is not balanced in any way :D 

 

If some of you guys wants to play this "game of devs" with me thanks, i'll be entertained :D



XxKuzkina_MatxX #6 Posted 08 May 2019 - 08:23 AM

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View PostDraco90, on 08 May 2019 - 11:06 AM, said:

I'm just wondering "if we want to give the 30B some of the historic relevance, what we could do?"

 

Make it more accurate than Leopard 1 which it was IRL, did you know that? :)

 

As a byproduct of trying to make this contraption of a shell work, the gun became intrinsically more accurate. They lowered the twist rate of the rifling on their version of the L7 to impart less spin on the projectile. Less spin doesn't only make this shell work better but also make APFSDS more accurate. Smart move, can't say the same about this shell design though. A ball bearing inside a tank shell, thanks but no thanks!


Edited by XxKuzkina_MatxX, 08 May 2019 - 09:44 AM.


Homer_J #7 Posted 08 May 2019 - 09:17 AM

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View PostNishi_Kinuyo, on 07 May 2019 - 04:55 PM, said:

Except that standard shells always have less penetration than special shells (barring HESH).

 

SU-100Y would like a word.

 

196 pen 440 damage standard AP shell.

171 pen 510 damage premium AP shell.



Draco90 #8 Posted 08 May 2019 - 12:55 PM

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View PostXxKuzkina_MatxX, on 08 May 2019 - 08:23 AM, said:

 

Make it more accurate than Leopard 1 which it was IRL, did you know that? :)

 

As a byproduct of trying to make this contraption of a shell work, the gun became intrinsically more accurate. They lowered the twist rate of the rifling on their version of the L7 to impart less spin on the projectile. Less spin doesn't only make this shell work better but also make APFSDS more accurate. Smart move, can't say the same about this shell design though. A ball bearing inside a tank shell, thanks but no thanks!

 

woa! This Is a information i was not aware of! Nice! Didn't expect 30B was more accurate than Leo! 

I can reply, a ball bearing inside a tank shell, why not!

:D 

Anyway loving talking on the matter. I thought the same (about buffing the 30B precision) knowing the rifled barrel was more precise than smoothbore, but more accurate than a German one? Damn.



WoT_RU_Doing #9 Posted 08 May 2019 - 01:13 PM

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View PostDraco90, on 08 May 2019 - 11:55 AM, said:

 

woa! This Is a information i was not aware of! Nice! Didn't expect 30B was more accurate than Leo!

I can reply, a ball bearing inside a tank shell, why not!

:D

Anyway loving talking on the matter. I thought the same (about buffing the 30B precision) knowing the rifled barrel was more precise than smoothbore, but more accurate than a German one? Damn.

 

You do know the L7 is British, not German?

XxKuzkina_MatxX #10 Posted 08 May 2019 - 02:21 PM

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View PostDraco90, on 08 May 2019 - 03:55 PM, said:

woa! This Is a information i was not aware of! Nice! Didn't expect 30B was more accurate than Leo! 

I can reply, a ball bearing inside a tank shell, why not!

:D 

Anyway loving talking on the matter. I thought the same (about buffing the 30B precision) knowing the rifled barrel was more precise than smoothbore, but more accurate than a German one? Damn.

 

Because this tiny part will become a weak point in a rather simple system. On top of that it's supposed to function properly and precisely over the span of its flight to the target and over the shell life span making it a mission critical part.

 

Adding an outer body to the shell limits the explosive mass inside. It's supposed to be a 105mm shell with say 10kg (for example) of explosives inside but because of the space taken by outer shell it can only hold 8kg of explosives making it effectively a 95mm shell. That didn't prevent the shell from having excellent penetration for its time with the added accuracy over HEAT-FS.

 

Machining tolerances needed to be very tight for those vents at the top and the bottom of the projectile case to make the inner capsule 'float' inside without spinning with the outer shell. That's why, i guess, it was a very expensive shell to manufacture.

 

The idea is neat but there are other ways simpler and cheaper to achieve similar results. :)



Draco90 #11 Posted 08 May 2019 - 08:48 PM

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View PostWoT_RU_Doing, on 08 May 2019 - 01:13 PM, said:

 

You do know the L7 is British, not German?

Of curse. And the Leo mounted the 105 mm Royal Ordnance L7A3 L/52 rifled gun. But i assume some aspects of the gun targeting devices and or rangefinding and or other little things were tweaked by Deutsch engineers. So, for making a long story short, i called the L7 on the Leo a German gun. Also to be noted, in that era, the L7 was the Gold standard for newborn MBTs. 

View PostXxKuzkina_MatxX, on 08 May 2019 - 02:21 PM, said:

 

Because this tiny part will become a weak point in a rather simple system. On top of that it's supposed to function properly and precisely over the span of its flight to the target and over the shell life span making it a mission critical part.

 

Adding an outer body to the shell limits the explosive mass inside. It's supposed to be a 105mm shell with say 10kg (for example) of explosives inside but because of the space taken by outer shell it can only hold 8kg of explosives making it effectively a 95mm shell. That didn't prevent the shell from having excellent penetration for its time with the added accuracy over HEAT-FS.

 

Machining tolerances needed to be very tight for those vents at the top and the bottom of the projectile case to make the inner capsule 'float' inside without spinning with the outer shell. That's why, i guess, it was a very expensive shell to manufacture.

 

The idea is neat but there are other ways simpler and cheaper to achieve similar results. :)

I agree, but all in all, the test showed the round was pretty good. Only the price (or, better, the performance price ratio) is not viable on the long run. This is proven by the fact that in the end all gun evolved to smoothbores and the shells fins stabilized (except for UK tanks, which make large use of HESH rounds still today and uses rifled guns).

 

All this said, still i cannot figure It out a way to implement this round in WoT...

(Its like a riddle to me, not actually want that round to be really implemented)



WoT_RU_Doing #12 Posted 08 May 2019 - 09:34 PM

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View PostDraco90, on 08 May 2019 - 07:48 PM, said:

I agree, but all in all, the test showed the round was pretty good. Only the price (or, better, the performance price ratio) is not viable on the long run. This is proven by the fact that in the end all gun evolved to smoothbores and the shells fins stabilized (except for UK tanks, which make large use of HESH rounds still today and uses rifled guns).

 

UK has been a big fan of HESH for a long time admittedly, and of course that is the reason behind the specification of rifled guns. However, that does NOT mean that the UK doesn't use FS ammunition, it's been using it as a standard ammo type for decades. The ammo simply has a rotatable flange around the outside. So, while the flange is fully influenced by the rifling, the sabot and FS round that it contains are mostly unaffected. Ironically, there's a good chance that there are ball bearings between the flange and the sabot ;)

However there are similarities in some respects to the anti-spinning method in the OPUS round, just different in exactly where the join is between the rotating section and the stable section. 


Edited by WoT_RU_Doing, 08 May 2019 - 09:37 PM.


vasilinhorulezz #13 Posted 08 May 2019 - 09:59 PM

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View PostNishi_Kinuyo, on 07 May 2019 - 04:55 PM, said:

Except that standard shells always have less penetration than special shells (barring HESH).

 

Cough..cough...Centurion 7/1 cough...cough...

Nishi_Kinuyo #14 Posted 08 May 2019 - 10:05 PM

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View Postvasilinhorulezz, on 08 May 2019 - 09:59 PM, said:

 

Cough..cough...Centurion 7/1 cough...cough...

Is HESH which I explicitely mentioned already in that post.

View PostHomer_J, on 08 May 2019 - 09:17 AM, said:

 

SU-100Y would like a word.

 

196 pen 440 damage standard AP shell.

171 pen 510 damage premium AP shell.

Yes, thank you for pointing out the only non-HESH exception. :facepalm:



XxKuzkina_MatxX #15 Posted 09 May 2019 - 05:01 AM

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View PostWoT_RU_Doing, on 09 May 2019 - 12:34 AM, said:

 Ironically, there's a good chance that there are ball bearings between the flange and the sabot ;)

 

One small detail to help visualize things better, the ball bearings inside the Obus G is an integral part of the projectile that will continue to travel with it till the target. The sabot gets discarded once it has existed the barrel, it doesn't need a ball bearing. A small machining tolerance between the driving band(s) and the sabot petals is all that's required for that very short journey. Adding a ball bearing under the driving band in this case can be dangerous because you're risking jamming the ball bearing altogether when the rifling bites into the band material.

 

The driving band is just a "buffer" used for a short period of time and for a limited purpose but the ball bearings in the french shell are an essential part for it to function properly all over its path to the target.

 

Spoiler

 


Edited by XxKuzkina_MatxX, 09 May 2019 - 06:22 AM.


WoT_RU_Doing #16 Posted 09 May 2019 - 10:42 AM

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View PostXxKuzkina_MatxX, on 09 May 2019 - 04:01 AM, said:

 

One small detail to help visualize things better, the ball bearings inside the Obus G is an integral part of the projectile that will continue to travel with it till the target. The sabot gets discarded once it has existed the barrel, it doesn't need a ball bearing. A small machining tolerance between the driving band(s) and the sabot petals is all that's required for that very short journey. Adding a ball bearing under the driving band in this case can be dangerous because you're risking jamming the ball bearing altogether when the rifling bites into the band material.

 

The driving band is just a "buffer" used for a short period of time and for a limited purpose but the ball bearings in the french shell are an essential part for it to function properly all over its path to the target.

 

Spoiler

 

 

Yeah, I'm not sure how the slipping driving band works on the FS ammo. It could be simply that it is simply lubricated or loose enough to slip rather than having ball bearings. The APDS round on the Chieftain didn't have it, as it was intended to spin, and to be honest I've never looked into the details of the FS rounds in enough detail to fully understand how they work, rather than just understanding the overall principles. (For example, I understand how the driving band works, but not how it is constructed so that it can rotate around the sabot, but not interfere with the sabots separation in flight.)  

XxKuzkina_MatxX #17 Posted 09 May 2019 - 12:48 PM

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View PostWoT_RU_Doing, on 09 May 2019 - 01:42 PM, said:

Yeah, I'm not sure how the slipping driving band works on the FS ammo. It could be simply that it is simply lubricated or loose enough to slip rather than having ball bearings. The APDS round on the Chieftain didn't have it, as it was intended to spin, and to be honest I've never looked into the details of the FS rounds in enough detail to fully understand how they work, rather than just understanding the overall principles. (For example, I understand how the driving band works, but not how it is constructed so that it can rotate around the sabot, but not interfere with the sabots separation in flight.)  

 

I'll spare you anymore of my rambling and leave a few images that demonstrate the construction perfectly.

 

Spoiler

 







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