Comprehensive Technical Review: BM “Oplot,” “Duplet”/”Nozh” Dynamic Protection System, and Modeling Deficiencies

Machinery of War Discussion Ground Vehicle
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Duplet doesn’t increase protection by a significant amount over Nizh vs 3BM42

…after being hit by BM-42 armor-piercing sub-caliber shells from a distance of 100 m, the residual penetration depth measured at an angle of 90° to the surface of the test plate was:

  • in the central part of the models with “Noz” ERA protection - 76 mm;
  • in the central part of the models with “Duplet” ERA protection - 58 mm

And this is also confirmed in this image where 3BM42 penetrates the first steel armor layer of the hull behind the Duplet module and you can see the STEF layer underneath

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2XV4V9pfmoQ_1900×1200 195 KB

If there was a 50mm plate seperating the two ERA cassetes in the Duplet module, I would doubt that 3BM42 could penetrate the first layer of the hull behind the Duplet module, because on its own, a setup of ~15mm RHA + ERA cassette+ 50mm RHA should leave a residual penetration of ~26mm in the surface of the witness plate mounted behind that setup. This setup is functionally just Nizh.
Instead the residual penetration after the Duplet module (which is 15mm RHA + ERA + middle layer + ERA) is over twice that.

As for the sideskirts. 164mm of steel in the sideskirts is total fantasy unless the Oplot weighed in excess of probably 80 tons. The interior of the sideskirts seem to just be polystyrene as spacers for the ERA casettes to stay in the correct orientation and a layer of STEF in the middle. The only steel is the outside casing which looks ~15-20mm, typical of a heavy flyer plate. Ingame it’s only 5mm, to me it can be argued that it looks quite a bit thicker then 5mm
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As far as I am concerned for the front hull ingame performs as expected to the info we have. It defeats DM43 and 3BM42 at 100m ingame. People expecting it to defeat DM53 are expecting too much

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T-80UD on the left, and BM Oplot on the right.
The general layout and structure of the hull front armor in the BM “Oplot” are fundamentally similar to those found in the T-80UD.

However, there is a crucial difference in the composition of the filler within the primary armor array:

  • In the T-80UD and other previous designs, the array’s cavities were typically filled with passive composite materials such as glass-textolite .
  • In the BM “Oplot”, these cavities are used to integrate elements of the “Duplet” Explosive Reactive Armor (ERA).
    With respect to the test-firings of the “Nizh” and “Duplet” ERA (which are approximately 15 years old), there is indeed a multitude of videos, photos, and reports available in open sources. In most cases, effectiveness certainly depends on the angle of impact and the type of projectile.

However, in nearly all of these materials, both “Nizh” and “Duplet” demonstrate high effectiveness. Even in photos showing damage, it is clear that the ERA activated and absorbed a significant amount of the projectile’s energy.

The Core Issue is with the Game Model:

My main point is not that “Duplet” cannot be penetrated, but that the in-game model of the BM “Oplot-T” is inaccurate and, as a result, understates the tank’s real survivability.

  1. Complex Structure: “Duplet” ERA is not just steel plates, but a multi-layered system with complex construction, including two types of ERA elements (HSCHKV-19A and HSCHKV-34P) within specialized cassettes.
  2. Side Thickness: Based on our calculations, the side module has a total thickness of 248 mm, of which 164 mm is attributed to the steel and intermediate layers, which is not reflected in the in-game X-ray view.
  3. Logical Basis: If this ERA were truly so ineffective, it would not have been integrated into the “Oplot’s” front armor in place of the passive glass-textolite filler.

There are many discussions where I and other users could provide comprehensive evidence to correct the model. However, due to certain forum rules (which prohibit direct quoting of classified material), we cannot fully reference technical documentation (such as the Thai Manual, which is declassified according to Ukrainian MoD Order No. 152 of 28.05.2009).

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IMG_1746

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Screenshot_2025-08-31_201133

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Your “secret” manual is just a textbook.

Spoiler

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I will make a few points to address your claims,

  1. Firstly, regarding the kinetic protection provided by Duplet:

According to the data provided, assuming the plate was angled at 68 degrees (same as T-64/72/80/84/90), 58mm penetration after encountering duplet, means 155mm residual penetration from LOS.

In-game, 3BM42’s penetration at 60 degrees at 100m is 524mm (the link you provided claims the penetration would be >550mm). Lets take the lowest figure of 524mm (Even in-game this number would be higher because BM42 effective penetration increases with the angle of the plate):

In game number for 60 degrees: 524-155=369mm penetration defeated.
Claimed real life number: 550-155 = 395mm penetration defeated.

This also lines up with my calculations of the tests done on the turret:
Approximately 120mm LOS penetration was observed at a firing angle of about 60 degrees. Taking the in-game number at 60 degrees, 524-120 = 404mm penetration reduction.

Averaging all these numbers, Duplet, including its covers and dampeners should stop 390mm of kinetic penetration.

Remember, the 369mm reduction is actually false because it uses BM42 penetration figure for 60 degrees not 68, so the average is actually lower than it should be.

In-game, Duplet stops approximately 292mm of kinetic penetration, including the protection provided by all covers and dampeners. 100mm less protection than it should provide.

Additionally, all of this is calculated for BM42, which has a segmented core, allowing it to perform better against ERA, mono-block projectiles such as BM60 or OFL F1 would be affected to an even greater degree. (As stated in the blog you linked)

  1. Regarding the 50mm steel plate of the BM Oplot.

I agree with your assessment that such a plate would have shown different results from the turret tests, and we should have observed very little residual penetration after two layers of ERA.

The issue is, BM Oplot certainly has this plate, there is no doubt about it, it can be seen in any factory images of the module, and the blueprint of the module mounted on BM Oplot confirms that this plate exists and is made of the same RHA as the rest of the module.

My personal theory is that the duplet module tested against BM42 was made according to the patent and did not contain this plate, but only dampeners similar to turret ERA, which is why it performed similarly to the turret ERA. However, ofc this is my theory, and I don’t have any concrete evidence to prove it.

  1. Conclusion:

If we model the Oplot’s armour without this 50mm plate, the ERA’s effectiveness against kinetic rounds should still be increased by about a 100mm at the very least.

If we take into account the increased protection against monoblock projectiles, and the 50mm plate, this protection should be even higher, but 390mm of reduction against Kinetic rounds is an absolute must.

As for the side skirts, its values should be adjusted according to the ERA performance calculated above, but overall I don’t have much issues with how they’re modelled in game. They seem to be accurate to the Thai version of the tank.

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Can the side skirt deflect ammunition, they don’t in game now

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It should be capable of defeating almost all shaped charge ammunition, and some APFSDS fired at an angle. Fixing the side armour thickness should also help with this.

According to the manual, the side ERA contains one model 34 ERA and 2 model 19. So in theory it should provide less protection than normal Duplet

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Btw do we have any info on the roof armour of BM Oplot? In game it is modelled to be around 25mm, in comparison, T-90M is 45mm, its why Oplot is so easy to over-pressure by hitting the sight with HE or HEAT.

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https://community.gaijin.net/issues/p/warthunder/i/tjNFRUTF1IzA

A report regarding an armour hole found on the turret was accepted, we can expect to see stronger resistance against overpressure.

Although I am still not sure where 25mm roof armour was found by the devs.

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Mate, you are wasting your time. This game is developed by russians. Any ukrainian tank in this game will always be 10x nerfed, no matter what evidence you present to the developers. They could never accept the fact that tank made by ukrainians is way better than any russian tank.

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It’s not like Duplet is underperforming but it’s like Russian heavy ERA is over performing Vs NATO-standard ammo so we expect Duplet to be way better as it is now? Isn’t it?

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Yeah, russian bias is a thing. But in case of russian ERA there is no bias, IRL it is really capable of stopping kinetic rounds, so in WT russian ERA is performing accordingly - they just didnt have to make it better than it is IRL. But in case of ukrainian ERA they had to make it worse, otherwise we would have situation where ukrainian tank is better than russian, because they would be same in terms of firepower and protection, but Oplot would also have reverse which is huge deal in game.

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It is literally underperforming, it should stop almost 400mm kinetic penetration minimum

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I found this video, might help with the vertical speed discussion.
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Clearly this movement is independent of the stabilizer since the tank is stationary. And it seems to be higher than 4.4 deg/sec.

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It seems there are more holes than we realized. Oplot’s turret holes

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I think this will also be fixed, seems to be the same hole as in this report. Community Bug Reporting System

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How come duplet can’t deflect apfsds while relikt can?

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the side ERA only intervenes against the rod’s trajectory at angles of 65 degrees or higher, whereas Relict becomes effective at a much earlier angle of 35 degrees. This results in the APFSDS rounds that penetrate Relict causing less damage than those hitting the Oplot’s base side armor, even though basic Relict ( without additional era packages)has a lower rated KE protection value. These two ERA types work differently, but I didn’t expect the difference in their effectiveness to be so pronounced.

It can deflect, but only deflect when the pen is already yellow or red😆

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Well I guess we know now, lol

https://x.com/andreibtvt/status/1975534194970239098?s=46&t=LO_FPDatH9sIUE5hlB6NPA