VertigoEx

On 9/21/2020 at 11:14 AM, SH_MM said:

 

A "study" that used comparable armor to the XM1 and came to the conclusion (in ballistic tests), that the XM774 can defeat this comparable armor at 4,000 meters distance.

 

I think that rather apparent now. The take away is that RHA is a near useless metric and more confirmation that round design matters a great deal.

The armor that the  M1 Abrams had when it was introduced probably wasn't sufficient against Monoblock DU rounds. Knowing what we know now about how much more effective a DU alloy monoblock rounds are against complex armor arrays this shouldn't be as surprising. What these tests show as much of anything, is the much increased effectiveness of rounds like the M774/M833 vs complex spaced arrays vs the previous generation of KE ammunition. 

Thankfully the for the M1 the USSR had nothing comparable in design to the M774 until the mid 1980s and IIRC, and  these were not all that common until the last days of the cold war. 

Had the cold war gone hot in 1983, the Abrams would have faced mostly 3bm-22 type rounds and earlier. I suspect (but don't know) based on the small amount of data available that the M1 would have had some protection against these rounds.

Boom

On 10/29/2019 at 12:58 PM, Beer said:

 

Unfortunately You didn't get the point of my post. I wanted to say that it's extremely difficult to define what does it mean to be the best and that even one against one comparison is not a good one. Even the very same thing can be the best for someone and a pain in the ass for someone else. Of course I also didnť try to claim that the T series tanks are the best  

 

With the T-90A example I tried to show an example of a scenario where such tank works maybe better than for example Abrams. The use of Abrams by similar military of Iraq has been rather problematic mainly due to claimed very low serviceable numbers. Regarding the actual combat loses I would say in both cases most of them can be attributed to an incompetence of their users. I know some T-90A were destroyed in Syria but despite having thousands of ATGM strikes on youtube we don't have any of a catastrophic explosion of a tank of late Soviet or post Soviet origin in Syria while we have tons of them with old T-72M1 or A models. 

 

By the way no T-90A loss is documented in Donbas among more than thousand of documented destroyed armoured vehicles. Only several T-72B3 and 72B mod.1989 from the relatively modern tanks. From what I have read the T-90A were used only briefly during the summer 2014 ofensive in Lugans area where they defeated the 1st tank brigade of Ukrainean army equipped with T-64BM in a night fight.  

 

Sure I understand that the Abrams M1A2S and Leopard 2A4 spectacularly destroyed on the videos were hits from side onto a tank sitting in the open. However to claim that the reputation for crew survivability of Abrams stayed intact after that is a bit too bold claim. In that very case if the crew was inside it was sure killed by the explosion. I am not saying the tanks are bad, I'm saying that a large part of their reputation comes from the fact that they have been mostly used by very potent militaries. When they are being used by less competent users the story changes. I think some Izraeli general said after Six day war that even if the militaries switched their hardware the result of the war would be most likely same. 

 

Thanks for the info about Leclerc in Yemen. 

Sorry for the late reply.. It does appear we agree on much. 

As for the T-90A in the UKR, a talk was given on youtube by a US adviser in the Donbas, he stated that T-90s were used in one the the battles for Donetsk airport and very hard to knock out. Perhaps he is mistaken. I will try and find he video

cheers.

On 10/28/2019 at 3:09 AM, Beer said:

I think that You can't say it even like this. The first thing is that you need to know your own doctrine and a way how you want to use the tanks. T-64/72/80 were built for completely different way of use than the western tanks. Comparing a one against one scenario is wrong for many reasons. 

 

We can see that T-90 and later models of T-72 were successful in Syria and suffered minimal loses despite the operational area being flooded with ATGMs, i.e. it looks like this tanks somehow work with the Arab armies which aren't known for being well trained and effective. As a result Uralvagonzavod won quite a lot of export contracts. On the contrary the reputation of Abrams and Leopard 2 was somewhat damaged in Yemen and Syria. Of course no tank is invulnerable and if it's sitting duck in the open it will be destroyed sooner or later in an ATGM-rich environment. However the long-built aura of invulnerability went to a trash bin. 

 

The media is a strong weapon today. Correct me if I am wrong but AFAIK there is no video of any catastrophic kill of T-90A from Syria. There are however several ones where T-90A or T-72B ob.1989 withstood direct hits from TOW 2 ATGMs to the turret and upper glacis covered by Kontakt-5. On the other hand the two videos with Turkish Leopard 2A4 and Saudi M1A2S exploding in a huge fireball after being hit by rather light Metis ATGM went viral very quickly. Interestigly there is no documented loss of Leclerc in Yemen (I remember only one damaged one by mine). 

 

There have been a few T-90s destroyed in Syria and in the Donbass iirc. The Tow-2 should not be that effective against anything with K5. A Tow-2A should have little issue against K5 armored tanks.  A captured T-90A was knocked out by a T-72 for example. APFSDS impact from the side. I suspect it was probably a BM-22/42. That said their combat performance seems to have been very good, and excellent in certain roles. 

The videos we see are selection bias, tank hunter killer teams in Yemen knew rather well that shooting an Abrams from the front was a death sentence, as you would be spotted by the very good thermal sights rather quickly, a kill not being all that likely. The videos I have seen suggest that the hits to the Abrams occur from the side and near oblique angles to the turret armor. The Abrams reputation for crew suitability seems to be intact. 

The Leo-2A4 used in turkey have very poor armor protection, and its likely that it is Type-B. Not sufficient for even the late 1980s. It isn't being used as it would be in the late 1980s however. 

There was one Lecerc driver killed with a ATGM hit the hull front. Not sure where the impact was, some suggested it was near the edge of the composite array. 

On 9/17/2019 at 9:23 AM, Scav said:

 

Putting this into perspective: M1A2 had 2t of DU added to bump the protection up from around 400-450mm (still "debated") to 600-640mm (while CE remained the same if not slightly decreased), out of 939mm LOS.

That's only for the turret front mind you, not even including turret side or hull front.

Yet, somehow, this new armour package that comes at "almost no weight penalty", barely four years after the latest armour package, reaches 600mm and 1200mm CE out of 860mm LOS while also including a protection increase for turret side and hull front?

 

 

I don't think it has been established with any certainty that the Swedish leaks represent HAP-1 or HAP-2 as opposed to a export armor package. 

US army magazine documents (which I don't place much faith in), place the CE rating of the M1A1 HA with HAP-1  around 1200 mm across the frontal arc vs 900mm in the Swedish tests. It is possible that a large trade off was made with an export armor package.

It could be that the Challenger 2 does get about 600mm vs KE across the frontal ARC and they are referencing its performance against  HAP-2 armor package, that would have a modest increases vs HAP-1 against contemporary long rods.. 690mm vs 640mm for example.

Or that the multi hit capability of the HAP-1/2 series is worse then the Challenger 2 solution. 

On 9/16/2019 at 6:06 AM, Militarysta said:

 

One small issue, the M833 pen value appears to be pen against RHA plate at 2km @ 0 degrees not 60. 

Penetration calc  @ 60  seems to be about 410-420mm from the math and dimensions I have.   

4 hours ago, SH_MM said:

 

Side skirts are 65 mm.

 

 

You are correct I measured just to the mounting bracket on the top end, Looking at my picture I see the error now.

4 hours ago, SH_MM said:

 

Side skirts are 65 mm.

 

 

That depends on a lot of factors. The steel simulators are smaller than the actual turret frontal surface and there is also the option that some of the extra weight was used to improve the side armor of the turret, in order to keep a homogenous protection level at the frontal arc.

 

There are also the curious case of (some of?) the other M1E1 pilot(s) having much thinner weight simulators:

 

There were probably lots of testing models seeing how much weight they could add progressively.

The 2.5' (estimate) plate, seems to cover most but not all of the area. It seems safe to assume that a good chunk of the weight goes into the extra structural armor, side armor, extra mounting brackets. That said 50-70mm of extra steel mass seems reasonable. The efficiency ME / TE increase vs KE vs BRL-1 is all conjecture at this point. Perhaps ~10% ME, seems reasonable based on increases of efficiency over the time period and era.

As has been said before by many, I feel like the RHA way of describing things is more the way for technical information being conveyed in a simple way to non technical people.

For example, the armor of a M1A1 with BRL-2 seems to be in the CIA document `~400mm across the frontal arc.  This isn’t an exact number but describes the type of weapon that tested against reliably defeats.

APFSDS are defeated in spaced composite arrays by being fractured and yawed and then the remaining elements being defeated by the back plate array. Rod design and dimensions seems to be more important then velocity in such a case. Eg (BM-22)

What I suspect is that the 400mm figure M1A1 with BRL-2 was tested successfully against APFSDS that pen around 400mm @ the impact angles approximating head on shots in the vertical from 25-30 deg in the Hz arc.

I suspect BRL used something like an M833 ( pen 380-400mm RHA ). This round was shot at different velocities at the armor package and found to offer reliable protection against a round of these dimensions and impact velocities. With the speed of the round being the least important variable.

So the statement means more accurately BRL-2 protects against DU monoblocks around  430mm x 30mm @ 1500 m/s. Because the statement was not say 480~ mm we can assume that longer rods at higher velocities defeat the packages (M829).

If what does this mean with regards to 125mm ammo BM-32-BM-42. These seem to be inferior round designs against spaced armor arrays. Superior against RHA yes, but against such arrays I have my suspicion that the increase in velocity may not overcome the limitations with regards to round design.  Again BM-42 seems to suffer against spaced armor arrays vs BM-32 for example. Could it be the armor arrays the BM-42 was designed against are as follows bellow.

19 hours ago, SH_MM said:

Andrei_bt once posted a drawing showing how the Soviets believed the MBT 80's armor would look like during the 1970s. I.e. the frontal armor was believed to be a sandwich of steel, aluminium-oxide, normal aluminium and steel.

 

That said I would not be surprised to find out that elements in the Bm-42 design allow it to overpass some spaced armor arrays.

5 hours ago, SH_MM said:

BRL-2 predates the use of tandem shaped charge warheads. The armor was finished before 1984 (when the M1IP entered service), the first Soviet tanks with Kontakt-1 ERA were fielded in 1983. The first NATO missiles with tandem warheads also entered service after the M1IP (BGM-71E TOW-2A: 1986, MILAN-2T: 1991, HOT-3: 1998, etc.).

 

The more reliable values (CIA estimates, values included in an article in a US Army magazine) I've seen suggest a hefty increase in protection against (single stage) shaped charge warheads: i.e. 900 mm instead of 700 mm steel-equivalent protection.

I am recalling from memory a thread some years ago on tanknet where it was discussed that tandem shaped charges were experimented on in the 1970s but left on the sidelines, however it was found they had improved performance against the newer armor arrays at the time.  I am open to correction on this of course. 

I suspect the statement of 900mm means defeats Tow-2 and perhaps Hellfire A type warheads tested against it.

Thanks for your thoughtful response as always.

4 hours ago, SH_MM said:

Well, to be fair it doesn't mention the frontal arc, but I believe that this seems to be self-evident based on the values. It is also noted that protection is dependending on the type of ammunition used, it could be the same situation as with the Leopard 2 (~450 mm protection against WC-cored steel APFSDS rounds, but only 350 mm against M111 Hetz and similar monobloc-designs).

 

Most estimates for the M1A1 are just random guesstimates from P. Lakowski and Zaloga ("M1A1 has 600 mm vs APFSDS"). 

It is difficult to gauge how much armor is here. I measured the front plate thickness to ~40mm and side skirts and around ~50mm on a M1 on display.  It appears that the armor here is a 1.25' and 2.5' thick plate, slightly elevated by welds.

Looking at the pictures, it is safe to assume that some of the weight simulators are simulating the extra material required to extend the turret another ~200mm.  If the thicker plates are 2.5' alone represents the extra steel weight (or Titanium ? ) of the inserts then we are looking at ~65mm at angle. If the efficiency of the armor improves only slightly against monoblock KE APFSDS, then 450-480mm VS KE head on seems reasonable and 400-430mm across the frontal arc. 

Good enough against most ammo of the time, head on long range probably good enough against BM42/32 but I have doubts at close range.  Also important to consider that BRL-2 also was probably designed to deal with tandem shaped charges as well so not all the improvements would have gone into KE protection.  Even if the improvements are on the high end of 500-520mm of estimates I have seen. It certainly wasn't sufficient against ammunition that came online 5 years after it was deployed (BM46). 

The BM42 did perform worse against spaced armor arrays vs BM32 IIRC.

2 hours ago, Militarysta said:

 

BM15 and BM22 was tested in Germany and Poland and definetly no - this round fails completly against spaced and spaced + NERA targets. About this I have no single doubt. -NERA just cracked whole penetrator  and set tungsten subrod in non linear way - so it hit backplate mostly its no front but side way. But im not so sure about BM26 - this roudnd was developerd to overpas I gen western special armour and completly diffrent build (whit stungsten subrod (od slug) in tail not in nose like in Bm15/22 was made to burst all NERA layers and made situation "tungsten sub rod vs backplat only". God idea and IMHO against erly Leporad 2A4 ot CR1 hull - enought. 

From some polish doc I just now that Germans in 1988 just...forgot about NERA layers and start to use ceramic tiles in sevral layers and shapes to incarase protection against long rod monolitic WHA and DU rods  - it was thread more dengour then estern partial rods. From other side - BM42 and BM32 was very heavy enemy and IMHO since KWS Leopard 2 was not protected agianst them.

The BM26 seemed to be the temporary solution until the more advanced rounds could be delivered. IIRC the Soviet view of Western Armor was not spaced composite arrays. Rather multi layer arrays of steel, early ceramics and aluminum. This was the nature of some the arrays that the Bm32/42 was tested against. The BM26 would perform better against such targets but worst against advanced Spaced NERA arrays. I still agree that it would probably be sufficient at close range against the hull arrays of the Leo-2 and C1. Against the M1 it might pen the area around the driver, to his left and right I don't see the eroded remnants of the slug doing much damage after impacting the fuel tanks.

As for the M1A1 and BRL-2, it looks like it incorporates some substantial weight with the weight simulators. I have never looked at the CIA document that states the protection as 380 across the frontal arc. I have heard values ranging from 400 to 450mm across the frontal arc.

Thinking out loud here. The M833 and BM42 have similar rod dimensions, with the M833 being a monoblock DU design vs BM42 segmented W.  While the Bm42 impacts at higher velocity, the design is less suited against composite arrays.  Any thoughts on which round would perform better against the spaced armor arrays at the time?

16 hours ago, SH_MM said:

It seems very questionable that the US military disclosed the composition of its armor at the height of the Cold War in an unclassified source available to the public. The usage of expensive titanium also would stay in conflict with the goal of making the Abrams an affordable main battle tank, being between 10-20 times as expensive as armor grade steel alloys and requiring special tools for machining.

 

It is possible that the author leaked the actual armor composition of the Abrams, but it seems more likely that he added his own speculations about the armor composition or mixed different arrays (maybe such a titanium NERA type was tested in the US) to come up with an explanation regarding "Chobham".

 

I think that you could be correct here. Or it could be one component of the armor mix of

Thermal sights also are in conflict with that goal. Depends on business and economic factors around such things in the late 1970s etc. The cost of titanium vs RHA or HHS could come down with economies of scale. The F-14 wing box is a good example of this. Once the sunk cost is accounted for the cost comes way down. So the USA certainly had the facilities to machine simple shapes out of 10-20mm titanium at the time.

The cost of one material in the armor being say 20,000 vs 2000 in 1980s USD isn't make or break for a budget, in light of the reality that, forging, machining DU is also astronomically high and the USA did invest billions in the 1980s to up armor the M1A1.

I do agree that this is far from proof of anything.  Another small clue that just prompts more questions then answers.

9 hours ago, Zadlo said:

Coming back to titanium, there's the another issue.

 

AFAIK in 2005 Americans started development of new production technology of titanium armor layers (whatever it may be) with using powder metallurgy and brand new alloy - Ti-5Al-2.5Fe. This alloy is cheaper and less toxic than Ti-6Al-4V but has a bit worse effectiveness. Using that alloy in M1 may cause that armor should be thickened (by around 5 - 10% I think) to achieve similar protection to armor using Ti-6Al-4V.

The USA has been working with powder metallurgy for some time. No surprise they moved onto Titanium alloys. There is good evidence that the M829A2 is improved in such ways.  I did some research about a year ago before my hard drive crash but wrote on SB form..that in the late 1980s the USA was conducting very serious research into improving " tensile and yield strength of heavy metal alloys. In some cases gaining improvements of 300-400% through some methods that caused  dissolution uniform recrystallization of ultra fine powders of various metals mixed with the main heavy metal. "

I will look for the paper to provide evidence of this.

Perhaps this is the improvement or one of a few of HAP-1---->HAP-2 also.

19 hours ago, Scav said:

As the plate in the picture is also at an angle ~8°, we can try to add these values together to get the rough LOS thickness: 1.25" @ 39° + 23" @ 8° + 4" @ 39° = ~30" or about 762mm.

Bit of an odd number (the raw thickness) as it isn't nice and round, guessing the actual length of that bottom plate is 22.75", which would make the raw thickness 28".

None of the angles are for certain as it wasn't measured, but the difference would be rather small.

A LOS of ~760mm isn't that bad..

Nice work.

1 hour ago, Zadlo said:

 

The same problems were also with thicker plates. Americans proved that in 1972 on 4" titanium plate.

 

Yes the effect of a plug of material being separated and pushed out was an issue for stand alone Ti-alloys up until very recently. Very hard steel alloys often had that same issue for that matter. 

The alloys in a laminate configuration with multiple thin plates and backing of Kevlar, polycarbonate and dyneema seemed to transmit the stresses laterally much more effectively and solve the issue of shear failure rather well, having a greater TE then Ti alloys alone and a far better ME then RHA.  

17 hours ago, Lord_James said:

 

On another thread, some people came to the conclusion that the titanium was not used as armor, but as mounting brackets for the NERA arrays. Due to the problems you mentioned, it would be illogical to use Ti as armor, but it would be completely sound to use it to support the armor. 

 

The source (1984 Army Magazine Volume 34 Pg 453) is rather clear in describing at least part of the armor.. " ..a pair of titanium alloy sheets sandwiching a layer of ballistic grade nylon.."

I don't have the source in front of me but I recall the common thickness of ballistic (hardened) grade titanium alloy plate around that time being approx 3/4 to 1 inch in thickness. 19-25mm.

Another possibility is the use of the titanium and ballistic fiber to encase and compress a ceramic backing layer. A low LD slug or APFSDS fragment impacting at yaw angle , a well confined ceramic layer with substantial backing would undergo interface defeat. 

17 hours ago, Lord_James said:

Lol, quora... 

 

Interesting though, I always assumed BRL-1 (Ballistic Research Laboratory; where the armor was made and tested) was the M1 array, and the M1 IP and M1A1 had the BRL-2, since their volume was similar, if not the same, but I could easily be wrong. 

I don't think that it is well documented, it is possible. The extra NERA elements and extra ~200 mm of space would increase its protection against contemporary soviet APFSDS (BM-26)  but do little against what was in the pipeline BM-42 etc. It seems logical to assume that during the development of the M829/829A1 that the USA felt that future soviet APFSDS would follow similar designs and performance. 

On 4/22/2019 at 4:48 PM, Scav said:

Interesting, perhaps the substantial % of additional weight going to the extra 6° of frontal arc protection is due to the much larger surface area on the side of the vehicle rather than the small frontal area?

 

Almost certainly this is the case.

On 4/22/2019 at 4:48 PM, Scav said:

 

I've only ever seen BRL-2 mentioned as being "improved armor" when talking about IPM1 vs M1, it's never mentioned how, so it seemed logical it was just the increase in thickness they were referring to....

Either way, do we know what they were using as simulant for this 115mm DU round? (or where we can find this paper?)

 

There are no official sources that I can find. There are some who suggest that the IPM1 is BRL-1 but more of it, and the M1A1 is BRL-2.  There are many pictures of M1E1 with what appears to be different weight simulators. Perhaps this is evidence of this.

Not evidence of anything but interesting take.

https://www.quora.com/Does-an-M1-IP-have-the-same-armor-as-a-baseline-M1A1

"No, the Armor on the M1 IP is an advancement of the BRL-1 Burlington Armor on the M1. (mostly just more of it) It was optimized to protect against HEAT warheads.

The Early M1A1 had a reformulation called BRL-2 which put alot more emphasis on KE protection..."

From a poster named Glen Girona. A man who claims to be a former Abrams crew member and was a non technical member of the Foreign Technology Assessment Support team FTAS.

I don't have the complete paper unfortunately. I would assume that the time period referring to  the X-m1 and not M1 is the late 1970s or very early 1980s.  The options available would be M774 or XM833. A M833 fired at a MV of 1600ms (guess of 115mm MV) would pen 390-400mm of RHA at 0-10 degree from vertical  at 1200m this falls to around 360-370mm. It seems reasonable that estimates for the M1 putting the armor around 350-370mm across the frontal arc are accurate and use early monoblock apfsds ammunition as the standard.

On 4/22/2019 at 4:48 PM, Scav said:

Yeah, but you'd also need a higher thickness of the plates to get the same effect, unless the first steel used was quite soft and the new alloy was very good...

Not by that much. At APFSDS velocities Titanium alloys are 1.45-1.6 times as effective for a  given mass of RHA. For CE it has a TE of 0.9 at a density 0.6 the weight.

Tankograd also states the material between the titanium allows is comprised of Kevlar or something similar.

There are disadvantages to Ti mostly associated with cost and difficulty manufacturing and welding thick armor plates. Thinner plates fail due to adiabatic shearing unless a ductile backing is used (aluminum for example). 

Perhaps the M1 (BRL-1) use a mixture of HHS and Ti based NERA elements.

On 3/31/2019 at 7:47 AM, Scav said:

 

 

 

In any case, reference threat for XM-1 (FSED I think) was XM579E1 (simulating 115mm APFSDS):

  Reveal hidden contents

Penetration was estimated at 161mm @60° and 1470m/s (either PB or 500m ish).
UK estimated XM-1 at 320-340mm, which coincides with the 115mm at 800-1200m requirement:

  Reveal hidden contents

As previously pointed out in this thread.
This doesn't talk about the XM-1s before the FSED it seems (why would they talk about an outdated design?).

 

So either CIA was talking about IPM1 turret ("long turret") or they somehow increased KE values for turret while keeping CE the same OR CIA was overestimating own armour?....
 

Anyway,  BRL-1 or early versions of Chobham don't seem to be very good against KE relatively speaking, NERA part itself seems to do very little for KE, simulated ammo (XM579E1) isn't the best against composite materials or complex targets.

Perhaps OG M1 only had ~350mm effective against KE on both hull and turret and IPM1 increased this to 400 or slightly higher, but I don't think that increasing the thickness of the turret with more NERA seems very efficient against KE.
IPM1/M1A1 probably have below 470mm against KE on turret (XM579E1), but maybe more against old slug type APFSDS and definitely less against 80s long rods.

 

This probably led to DU equipped M1s...... to compensate for relatively poor KE protection.

I found this and reposted this on the SB forum.

Interested in what others here think..

More insight into assumed threats to early 1980s armor. If it is a threat to a IFV it is a threat to tanks that fight with them.

So the USA experimented with armor arrays similar to the Xm-1 that could defeat 115mm DU ammo across the frontal arc. So at some point the USA was testing BRL-1 or BRL-1 like armor arrays against not use W, but DU ammo. 

Perhaps this is what evolved into BRL-2, or a reformulated version of BRL-1.

IIRC Tankograd has evidence that suggests that  BRL-1 on the M1 uses titanium alloys with or in place of steel in the NERA array.  That would increase the ME, but not the TE against KE rounds no?