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#61 Wiedzmin

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Posted 15 March 2018 - 0340 AM

 

 

OTOH Soviet tanks could also be defeated by 120 mm DM33 APFSDS:

 

all tanks will be penetated in this areas with almsot any APFSDS 


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#62 EasyE

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Posted 18 March 2018 - 1452 PM


NATO tank armour was quite overrated by the internet community.

 

In many cases this appears to be true.. It does seem that the first M1 was about 400mm vs KE and 750mm vs CE.  A bit of a boost from the XM1 it appears. This seems to make sense in light of past statements, the often quoted 350mm vs KE probably refers to 30 deg off center and a bit more then 400mm vs KE head on for the M1 that entered limited production in 1979-80.

 

I am not sure about the values  for the M1A1. 380mm vs KE..The gun sheild? glacis, hull front? turret front? from head on ? 30 deg?..

 

That said RHA doesn't seem to instructive against KE projectiles at the time. As was mentioned by you, the design of soviet APFSDS was rather primitive and probably not very effective against spaced composite arrays.  A great deal of the RHA penetration of say the Bm-22, relies on the tungsten slug staying intact and not starting to tumble inside the array. Velocity seems to matter less then round design here..  Again, I suspect that the armor arrays of the early 1980s probably were effective against these types of round. However early mono block rounds m833 and BM-32 were a much greater challenge.

 

 

"However according to the man who held the presentation (from which these images are taken), no NATO tank was protected against Soviet 125 mm APFSDS during the Cold War."

 

This seems like a vague statement. Which tank ? Where? What round from what distance?  It seems M1A1HA wasn't completely immune against the Bm-42, but it was well protected against it from the 30 deg arc. It seemed to be protected against the m829 and m28a1 in GW1.. It is also important to keep in mind that the best soviet APFSDS of the 1980s as a segmented tungsten round with a long-rod that was shorter, and lighter then the M833.

 

 

 

Are there any studies, statements, or documentation regarding the performance of Bm-22/26/29 type rounds against spaced and composite armor arrays?


Edited by EasyE, 18 March 2018 - 1512 PM.

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#63 EasyE

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Posted 18 March 2018 - 1516 PM

There is more, but not relevant to the topic:

 

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Comparison of M1A2 export armour vs Swedish armour package tested as alternative. According to Sweden DU does not improve protection per weight, but per armour thickness. Given that Sweden didn't mind increasing the armour thickness, the tested protection level might have exceeded the one of the M1A2 with DU (at least the Swedish armour package was heavier overall).

 

 

Did this export armor package contain DU elements?


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#64 bojan

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Posted 18 March 2018 - 1805 PM

IIRC no.


Edited by bojan, 18 March 2018 - 1805 PM.

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#65 methos

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Posted 19 March 2018 - 0846 AM

all tanks will be penetated in this areas with almsot any APFSDS


Well, most likely. But the amount of surface is different, just like the amount of armour. The T-80U and most Soviet tanks don't have proper mantlet armour modules, so they are more vulnerable. On some of the more modern tanks, the gun mantlet is a composite armour block with a thickness of more than 600 mm. The gaps between the armour modules of turret and gun mantlet are much smaller compared to the Soviet design, which has only cast steel armour at the center of the turret.
 

In many cases this appears to be true.. It does seem that the first M1 was about 400mm vs KE and 750mm vs CE. A bit of a boost from the XM1 it appears. This seems to make sense in light of past statements, the often quoted 350mm vs KE probably refers to 30 deg off center and a bit more then 400mm vs KE head on for the M1 that entered limited production in 1979-80.

 
I don't see why this should be a "bit of a boost from the XM1". There is no indication that the XM1 was worse armoured or the M1 Abrams is better armoured than previously. The British data is based on the XM1 FSED prototype (which pretty much is what went into production in 1980) and the estimated protection levels seem to be focused on the full frontal arc of the tank. Hence 340 mm (at 30°) and 400 mm (at 0°) could very well be identical, as you said. The hull armour would be slightly weaker (320 mm along the frontal arc - but it seems that it is the weakest when hit at 0°).
 
There is however one caveat: the document from which the value "400 mm" is taken, does not specify that it is the M1 Abrams. It seems most likely - but in theory it also could refer to the M1E1 prototypes already in exsitence at that time.
 

I am not sure about the values for the M1A1. 380mm vs KE..The gun sheild? glacis, hull front? turret front? from head on ? 30 deg?..


It seems very unlikely that the value would refer to the gun shield for various reasons. It is always hard to find out what authors mean when posting just a single value; it could be the minimum protection along the frontal arc, it could be referencing the guaranteed protection achieved along the surface at certain angles of impact (as done in Sweden, i.e. at least 380 mm protection being achieved on 50% or 75% of the surface). It is also possible that the value "380 mm" refers to the protection of turret/hull at 0° - the reduction in protection (despite adding more armour weight) might be the result of using more advanced APFSDS rounds for the test (the document specifically mentions that penetration will "vary depending on the munition used").
 

That said RHA doesn't seem to instructive against KE projectiles at the time. As was mentioned by you, the design of soviet APFSDS was rather primitive and probably not very effective against spaced composite arrays. A great deal of the RHA penetration of say the Bm-22, relies on the tungsten slug staying intact and not starting to tumble inside the array. Velocity seems to matter less then round design here.. Again, I suspect that the armor arrays of the early 1980s probably were effective against these types of round. However early mono block rounds m833 and BM-32 were a much greater challenge.

 
Yes, the performance of older types of APFSDS ammunition should be lower against special armour targets (composite, spaced, reactive) than against steel, while more modern APFSDS ammo actually is optimized to penetrated special armour targets and does perform worse against simple (semi-infinite) steel. The earlier Soviet rounds did have trouble with relatively easy targets, even single sloped steel plates could result in a reductioon of the penetration capabilties. This was fixed (to some extend) with the 3BM-26 "Nadezhda" APFSDS, which was the first round designed to defeat laminated and spaced armour as main threats. Later rounds such as the 3BM-42 "Mango" were/are tested against a seven-layered and a ten-layered special armour array as main targets. It should however be noted that the Soviet criteria for armour penetration into steel was a lot stricter, requiring 80% of the rounds to reach this penetration value. The US military seems to list (always?) the ballistic limit, i.e. at least 50% of the rounds achieve the penetration value. This raises questions about the criteria used for armour protection...
 
However I still don't see any reason to speculate that the (X)M1 was designed and tested against advanced APFSDS rounds with monoblock penetrator. The protection requirements were focused on the Soviet 115 mm smoothbore gun firing APFSDS ammo. What ammo was used in the US tests? Actual ammunition captured by Israel? A special APFSDS designed specifically to represent the projected developments of the Soviet Union? Maybe they did use the M735 APFSDS or a prototype of a future 105 mm round? Currently we don't know, therefore I wouldn't make any specluations regarding superior efficiency against Soviet rounds.
 
The armor tests for the XM1 tanks were made in 1976, at this point of time the XM774 development apparently wasn't started. This would suggest that - unless the US military used a special protoype design to test the XM1's armor - that the XM1 was tested against an "inefficient" APFSDS round such as the M735 or a Soviet design. The development of the FSED tanks was done in 1977/1978, with the first tank beimg delivered in February 1978. This already looks identical to the later M1 Abrams. R. P. Hunnicutt mentions that the FSED tanks feature improved armour protection compared to the XM1 prototypes (they also are a lot heavier), but this statement might be related to the armour coverage (the armour modules cover more of the surface; less of the sloped roof is exposed to fire; also a composite armoured gun shield was adopted).
The 11th FSED pilot vehicle was used in 1979 for the final armour tests against "various types of ammunition at typical combat ranges" and an anti-tank mine (that destroyed its suspension). It seems that this would be the first possible option to test the Abrams' armour against the XM774 prototype design (first date for firing tests of the XM774 I could find was 1978), but I don't think it is very likely given that the previous tests were done against other munitions and the final tests just were used to gather sensor data.
 
I think this statement regarding the different efficiencies of APFSDS ammunition against (modern) composite armour is more relevant for the graph showing the different Leopard 2 protection levels, that I posted earlier.That's one graph showing the protection level of five different Leopard 2 variants... how was this data obtained? Where all of these tanks tested against old Soviet ammo (and all variants would subsquently perform worse against newer rounds), where all tanks tested against newer ammo (and all would subsequently perform better against older rounds) or did somebody think it makes sense to mix protection data against different types of ammunition with different efficiency into one graph?
 

This seems like a vague statement. Which tank ? Where? What round from what distance? It seems M1A1HA wasn't completely immune against the Bm-42, but it was well protected against it from the 30 deg arc. It seemed to be protected against the m829 and m28a1 in GW1.. It is also important to keep in mind that the best soviet APFSDS of the 1980s as a segmented tungsten round with a long-rod that was shorter, and lighter then the M833.

 
I guess the most likely option is "all tanks at expected combat ranges". The British assessment of the XM1 FSED's protection was that it could be defeated within the frontal arc at ranges well beyond 4,000 m. I am fairly sure that the British military had a good idea about how Burlington/Chobham performs against APFSDS ammo...
 
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What 115 mm APFSDS did the US project for the 1980s?
 
The M1A1 Abrams doesn't seem to be much better protected, with the M1E1 using two one inch thick (?) steel plates on the turret and a single one inch thick (?) steel plate of the hull as weight demonstrators for the enhanced armour. Given that the weight demonstrators are physicially smaller than the actual surface covered by armour, the areal density of the armour package might have improved only a bit. According to British documents on the development of Chobham armour, Burlington/Chobham armour provided 1 to 1.5 times as much protection against KE than a steel plate of equal weight; however this values might have been obtained using APDS ammo with relatively brittle WC cores based on the date of these documents. Achieving the mass efficiency of 1.5 against KE meant that the efficiency against shaped charges would be reduced from ~3 to ~2, an option probably not chosen by the US military (which viewed protection against shaped charges as priority for the Abrams).
 
That would lead us - and I know that's a lot of speculation, but unluckily we have only a limited amount of sources available at the time - to conclude that the 380 mm protection (at 30°) against KE mentioned earlier matches perfectly with the British armour estimate of 340 mm (at 30°) against KE of the M1 Abrams. Assuming that the "400 mm vs KE" is valid for the M1 Abrams from 0° and that the armour efficiency stays the same regardless of angle, the M1A1 would then have up to 447 mm against KE at 0°. The hull armour would be even more vulnerable.
This would mean that the M1A1 could be defeated using 3BM-42 "Mango" and 3BM-32 "Vant" ammunition from ranges up to 2,000 m (and slightly above).
 
The M1A1 HA with DU armour seems to be very well armoured - but only along a small frontal arc. The side armour, the hull armour and the gun shield lack the DU upgrade and might be kept on the same level as the M1A1 or be identical to the M1A2's export armour package. The latter would put hull protection at a minimum of 350 mm vs KE along a 25° arc (so ~300-320 mm along a 30°) - vulnerable to even older APFSDS ammo at 2,000 m - and mean that the turret sides hit from 20° provide only 480 mm steel-equivalent protection against APFSDS ammo. Thus at 30° the M1A1 HA's turret could be penetrated by Vant and Mango at 2,000 m range or at 20° and 1,500-2,000 m range. The turret cheek armour makes up about 20% of the tank's surface along the 30° arc; a bit more when being hull down.
Given that the average combat distance in the Fulda Gap, where the US Army envisioned the place of a massive Soviet tank attack in case of a "Hot War", is less than 1,000 m, the M1A1 HA would still be rather vulnerable to Soviet tanks.
 
The Leopard 2 with its original armour package has only 20% of its surface reaching a protection level of 400 mm or more against an unknown KE round, while 50% reach a protection level of 300 mm or more against the same unknown round. That would mean that at any place (besides the frontal turret cheeks) the tank is vulnerable to 125 mm APFSDS even at long ranges, with the cheeks potentially resisting a strike of Mango (at best) at 2,000 m range - at least if the unknown round is not a modern monoblock penetrator; otherwise the protection level could be a little bit higher. The second generation armour package adopted in 1988 would allow 50% of the tank's surface along the frontal arc to reach ~380 mm or more steel-equivalent protection against the unknown round, while 28% of the surface reach 500 mm or more steel-equivalent protection against the unknown round. So the Leopard 2 would be able to withstand Mango and Vant at ~1,500 m, but only at the turret cheeks.
 
Regarding the M1A1 HA stopping the M829(A1) APFSDS during friendly fire during the Gulf War: There are too many unknown factors for me. Where was the tank hit, at what range and how much armour does the M829(A1) penetrate? A few pages earlier it was assumed that the M829 has a 540 mm long penetrator, however new information suggests that it is only 440 mm long (480 mm maximum, but that includes the section that screws on the fin segment).
 

Did this export armor package contain DU elements?


No, the export armour package lacked the DU (it might have been replaced with other materials). The Swedes however list essentially the same combat weight for the tested tank (with export armour) as the US M1A2 (with DU armour). Likewise Australian and some Egypt tanks seem to have the same weight as US M1A1 HA/AIM tanks, despite not using DU. That implies that the DU was replaced with another material (General Dynamics could also have developed a completely new and different armour package, but this seems less likely to me, given the effort required for this). 
 
The M1A2 was alternatively tested with a Swedish armour package, which to my knowledge was added on-top of the export armour and consisted of armour modules made by a Swedish company, but based on licenced German technology (i.e. MEXAS). When fitted with the add-on armour modules, the M1A2 would weigh a lot more than the US M1A2 with DU armour or export armour, which together with statements about Swedish research on DU armour (and the fact that the add-on armour modules also covered the hull, where no DU is added), makes me believe that the M1A2 with "Swedish armour" was better protected than the US M1A1 HA/M1A1 HC/M1A2.


Edited by methos, 19 March 2018 - 0855 AM.

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#66 Interlinked

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Posted 19 March 2018 - 1035 AM

Does anyone have some data on the mass efficiency of the spaced armour in the T-72B obr. 1985?
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#67 EasyE

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Posted 19 March 2018 - 1600 PM

 

all tanks will be penetated in this areas with almsot any APFSDS


Well, most likely. But the amount of surface is different, just like the amount of armour. The T-80U and most Soviet tanks don't have proper mantlet armour modules, so they are more vulnerable. On some of the more modern tanks, the gun mantlet is a composite armour block with a thickness of more than 600 mm. The gaps between the armour modules of turret and gun mantlet are much smaller compared to the Soviet design, which has only cast steel armour at the center of the turret.
 

In many cases this appears to be true.. It does seem that the first M1 was about 400mm vs KE and 750mm vs CE. A bit of a boost from the XM1 it appears. This seems to make sense in light of past statements, the often quoted 350mm vs KE probably refers to 30 deg off center and a bit more then 400mm vs KE head on for the M1 that entered limited production in 1979-80.

 
I don't see why this should be a "bit of a boost from the XM1". There is no indication that the XM1 was worse armoured or the M1 Abrams is better armoured than previously. The British data is based on the XM1 FSED prototype (which pretty much is what went into production in 1980) and the estimated protection levels seem to be focused on the full frontal arc of the tank. Hence 340 mm (at 30°) and 400 mm (at 0°) could very well be identical, as you said. The hull armour would be slightly weaker (320 mm along the frontal arc - but it seems that it is the weakest when hit at 0°).
 
There is however one caveat: the document from which the value "400 mm" is taken, does not specify that it is the M1 Abrams. It seems most likely - but in theory it also could refer to the M1E1 prototypes already in exsitence at that time.
 

I am not sure about the values for the M1A1. 380mm vs KE..The gun sheild? glacis, hull front? turret front? from head on ? 30 deg?..


It seems very unlikely that the value would refer to the gun shield for various reasons. It is always hard to find out what authors mean when posting just a single value; it could be the minimum protection along the frontal arc, it could be referencing the guaranteed protection achieved along the surface at certain angles of impact (as done in Sweden, i.e. at least 380 mm protection being achieved on 50% or 75% of the surface). It is also possible that the value "380 mm" refers to the protection of turret/hull at 0° - the reduction in protection (despite adding more armour weight) might be the result of using more advanced APFSDS rounds for the test (the document specifically mentions that penetration will "vary depending on the munition used").
 

That said RHA doesn't seem to instructive against KE projectiles at the time. As was mentioned by you, the design of soviet APFSDS was rather primitive and probably not very effective against spaced composite arrays. A great deal of the RHA penetration of say the Bm-22, relies on the tungsten slug staying intact and not starting to tumble inside the array. Velocity seems to matter less then round design here.. Again, I suspect that the armor arrays of the early 1980s probably were effective against these types of round. However early mono block rounds m833 and BM-32 were a much greater challenge.

 
Yes, the performance of older types of APFSDS ammunition should be lower against special armour targets (composite, spaced, reactive) than against steel, while more modern APFSDS ammo actually is optimized to penetrated special armour targets and does perform worse against simple (semi-infinite) steel. The earlier Soviet rounds did have trouble with relatively easy targets, even single sloped steel plates could result in a reductioon of the penetration capabilties. This was fixed (to some extend) with the 3BM-26 "Nadezhda" APFSDS, which was the first round designed to defeat laminated and spaced armour as main threats. Later rounds such as the 3BM-42 "Mango" were/are tested against a seven-layered and a ten-layered special armour array as main targets. It should however be noted that the Soviet criteria for armour penetration into steel was a lot stricter, requiring 80% of the rounds to reach this penetration value. The US military seems to list (always?) the ballistic limit, i.e. at least 50% of the rounds achieve the penetration value. This raises questions about the criteria used for armour protection...
 
However I still don't see any reason to speculate that the (X)M1 was designed and tested against advanced APFSDS rounds with monoblock penetrator. The protection requirements were focused on the Soviet 115 mm smoothbore gun firing APFSDS ammo. What ammo was used in the US tests? Actual ammunition captured by Israel? A special APFSDS designed specifically to represent the projected developments of the Soviet Union? Maybe they did use the M735 APFSDS or a prototype of a future 105 mm round? Currently we don't know, therefore I wouldn't make any specluations regarding superior efficiency against Soviet rounds.
 
The armor tests for the XM1 tanks were made in 1976, at this point of time the XM774 development apparently wasn't started. This would suggest that - unless the US military used a special protoype design to test the XM1's armor - that the XM1 was tested against an "inefficient" APFSDS round such as the M735 or a Soviet design. The development of the FSED tanks was done in 1977/1978, with the first tank beimg delivered in February 1978. This already looks identical to the later M1 Abrams. R. P. Hunnicutt mentions that the FSED tanks feature improved armour protection compared to the XM1 prototypes (they also are a lot heavier), but this statement might be related to the armour coverage (the armour modules cover more of the surface; less of the sloped roof is exposed to fire; also a composite armoured gun shield was adopted).
The 11th FSED pilot vehicle was used in 1979 for the final armour tests against "various types of ammunition at typical combat ranges" and an anti-tank mine (that destroyed its suspension). It seems that this would be the first possible option to test the Abrams' armour against the XM774 prototype design (first date for firing tests of the XM774 I could find was 1978), but I don't think it is very likely given that the previous tests were done against other munitions and the final tests just were used to gather sensor data.
 
I think this statement regarding the different efficiencies of APFSDS ammunition against (modern) composite armour is more relevant for the graph showing the different Leopard 2 protection levels, that I posted earlier.That's one graph showing the protection level of five different Leopard 2 variants... how was this data obtained? Where all of these tanks tested against old Soviet ammo (and all variants would subsquently perform worse against newer rounds), where all tanks tested against newer ammo (and all would subsequently perform better against older rounds) or did somebody think it makes sense to mix protection data against different types of ammunition with different efficiency into one graph?
 

 

We don't really know enough about the process for testing, replacing and implementing the armor packages (inserts etc) to speculate about how implementing even a minor upgrade would appear.  For now we I think we have to accept we have the only most basic outline of what went on.

 

I find this interesting.

 

"Faced with this latest barrage of criticism, Chrysler Corporation has issued a bold challenge to its antagonists. "I'd be prepared to have them shoot anything they can find at the XM-1, including the latest Eastern bloc weapons," exclaims Louis Felder, manager of the XM-1 engineering program in Detroit. "We've done that and we've done that more than once."

 

"https://www.csmonito...21/112144.html"

 

I would be interested in knowing what they thought the latest eastern block weapons were. Or what was used as a stand in.

 

 

As for the M1E1/M1A1.

 

https://encrypted-tb...Yx-BCPFvoCKVhAY

 

I disagree that the weight simulators don't cover the area protected. They do appear to cover the entire area of the inserts and be thicker then 1 inch each. Or there were various M1E1 weight simulators..I would be surprised BRL, spent over 8 years during the height of the cold war sitting on their hands not working on how to squeeze greater ME and TE out of armor designs. Do the inserts have harder steel, is there a ceramic layer, super hard shatter plate, ballistic aluminum back plate?  Again we are trying to work backwards to get an answer that isn't even that relevant. Thinking in terms of RHA is the most basic starting point for understanding these types of armor packages. The M1E1 might have an armor package that completely protects the turret from rounds like the BM-26/29 but offers poor protection against rounds such as the Xm829. I would be surprised if the M833 and xm829 wasn't tested against armor packages proposed for this vehicle.

 

It could be (probably in my opinion also) that protection from mono block rounds was not a priority for the M1A1 that more advanced HEAT warheads was seen as the bigger threat.

 

"Later rounds such as the 3BM-42 "Mango" were/are tested against a seven-layered and a ten-layered special armour array as main targets." I have heard this but also heard it was a myth, that it was impossible for the the steel jacket encasing the two rods to behave in the way required (melting during the penetration process etc).  If you have a source I would appreciate it, as I am confused on this issue.

 

The IMHO M833 is a better round then the Bm-42. Longer thicker heavier DU rod. Worse against steel but perhaps far better against complex targets.

 

http://i.imgur.com/TenM7Mn.jpg

 

In tests the DU and WU versions of the M833 were tested against complex targets. You can see that the DU version vastly out preforms the WU version against complex targets. I would love to know what the layout of " increased difficulty targets" was.

 

As for the M829, it does appear that Wiedzmin posted a picture of it next to some target blocks. It does appear it went through >600 mm of titanium which puts it in the ballpark of 550mm vs RHA. There is also RHA block  bellow it.

https://i.imgur.com/DGMHkoTg.png

 

With regards to the Swedish test. I also would be surprised if the armor package of the M1A1HA (1988-90) out preforms the Swedish armor package vs KE. This makes sense, the often quoted armor values for the M1A1HA was 600mm vs KE. I strongly suspect this is from 30 deg. Which would place it between the American armor package and much newer Swedish one.


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#68 Interlinked

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Posted 19 March 2018 - 2303 PM

Moved-

Edited by Interlinked, 22 March 2018 - 1652 PM.

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#69 Wiedzmin

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Posted 20 March 2018 - 0402 AM

 

Well, most likely. But the amount of surface is different, just like the amount of armour. The T-80U and most Soviet tanks don't have proper mantlet armour modules, so they are more vulnerable. On some of the more modern tanks, the gun mantlet is a composite armour block with a thickness of more than 600 mm. The gaps between the armour modules of turret and gun mantlet are much smaller compared to the Soviet design, which has only cast steel armour at the center of the turret.


 

"more than 600" where ? Leo2A4 mantlet 420mm and weight only 630kg, it 100% better than soviet mantlet in terms of CE protection, but in case of KE, it will be penetrated by any 100-125mm APFSDS imho.

 

"gaps" are the same. more or less. in case of Leo2A4 again. whole right front part one big "gap"

 

i agree that the casted turrets have many problems with turret roof area.


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#70 EasyE

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Posted 21 March 2018 - 0125 AM

 

 

Well, most likely. But the amount of surface is different, just like the amount of armour. The T-80U and most Soviet tanks don't have proper mantlet armour modules, so they are more vulnerable. On some of the more modern tanks, the gun mantlet is a composite armour block with a thickness of more than 600 mm. The gaps between the armour modules of turret and gun mantlet are much smaller compared to the Soviet design, which has only cast steel armour at the center of the turret.


 

"more than 600" where ? Leo2A4 mantlet 420mm and weight only 630kg, it 100% better than soviet mantlet in terms of CE protection, but in case of KE, it will be penetrated by any 100-125mm APFSDS imho.

 

"gaps" are the same. more or less. in case of Leo2A4 again. whole right front part one big "gap"

 

i agree that the casted turrets have many problems with turret roof area.

 

 

 

I think the SB armor model for the 1992 Leo-2A4 is given a 600mm vs KE value...He might be inferring it from that.

 

I would be interested in knowing the rational on some of the armor values. They have good access to data and Nils no doubt to takes these things rather seriously. The armor values were originally based on Paul Lakowski's work and have been updated more then a few times. I am not so sure the armor values in the diagrams represent what is currently in the game...

 

The 600mm vs KE seems a bit high.....I am sure they didn't just guess though, and I suspect they know more then I.


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#71 methos

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Posted 21 March 2018 - 1550 PM

We don't really know enough about the process for testing, replacing and implementing the armor packages (inserts etc) to speculate about how implementing even a minor upgrade would appear. For now we I think we have to accept we have the only most basic outline of what went on.

I find this interesting.

"Faced with this latest barrage of criticism, Chrysler Corporation has issued a bold challenge to its antagonists. "I'd be prepared to have them shoot anything they can find at the XM-1, including the latest Eastern bloc weapons," exclaims Louis Felder, manager of the XM-1 engineering program in Detroit. "We've done that and we've done that more than once."

"https://www.csmonito...21/112144.html"

I would be interested in knowing what they thought the latest eastern block weapons were. Or what was used as a stand in.


The statement by the Chrysler Corporation is typical marketing talk, I would consider this to be rather meaningless. BAE Systems, General Dynamics and PSM GmbH are all claiming that their respective IFV designs offer "best in class protection", yet all vehicles fall in the same weight class and there certainly are differences in the protection level.

Claims like "the latest Eastern bloc weapons" are silly, given that the United States military dramatically underestimated the penetration performance of Soviet ammunition. The report which mentions the "400 mm vs KE, 750 mm vs CE" protection level provided by "one version of the M1 turret armor" also includes US estimates of Soviet armour penetration:
epS7vp2.png

Soviet sources (with their stricter criteria for armour penetration!) mention that the 115 mm BM3 with tungsten carbide slug penetrates 270 mm steel armour at 2,000 m and the 125 mm 3BM-22 Zakolka penetrates 380 mm steel armour at 2,000 m.
 

As for the M1E1/M1A1.

https://encrypted-tb...Yx-BCPFvoCKVhAY

I disagree that the weight simulators don't cover the area protected. They do appear to cover the entire area of the inserts and be thicker then 1 inch each. Or there were various M1E1 weight simulators..I would be surprised BRL, spent over 8 years during the height of the cold war sitting on their hands not working on how to squeeze greater ME and TE out of armor designs. Do the inserts have harder steel, is there a ceramic layer, super hard shatter plate, ballistic aluminum back plate? Again we are trying to work backwards to get an answer that isn't even that relevant.


I have seen this photo of the M1E1 turret armour weight simulator plates, but unfortunately it shows only half the truth due to the perspective. If you look at other photos from other angles, you'll notice that the two steel plates are spaced (you can even see the weldlines for the spaces in your photo).

TxwqEAF.png

As for the coverage of the weight simulators...
LUh9dmD.pngQxg4e6P.png?1

The weight simulators cover a much smaller surface than the actual armour array should cover (we don't know if it does, but it really should...). Maybe the thickness of the plates is slightly higher or lower than one inch, but it seems to be rather close to this value. We also don't know if some of the simulated weight was used at places other than the frontal armour - maybe it was also used to simulate heavier protection elements in the side armour. It's a lot of speculation, but we don't have enough sources.

As for the protection provided by the enhanced Burlington armour, I remember having read a two page report about US armour development, where the Army came to the conclusion that it had underestimated the threat of KE rounds and not invested enough into the development of an armour array to protect against it, but new armour incorporating depleted uranium would address this issue. I will try to find it again.

The British military worked on Chobham armour for about 20 years before adopting it. Armour development takes time and a need for higher protection. If the protection level is sufficient against 115 mm APFSDS ammo and protection against 125 mm APFSDS cannot be achieved while staying at the desired weight, it is not really a priority to improve anti-KE performance. The biggest issue for the US military was apparently the low volume for special armour, which is why they went with depleted uranium - very good TE against KE ammo, but no the best ME. The CATTB shows an alternative development option - low density armour (without DU), but a much greater special armour thickness (specified to be either 1,000 or 1,200 mm) to provide a higher level of protection than the M1A1 HA.
 

Thinking in terms of RHA is the most basic starting point for understanding these types of armor packages. The M1E1 might have an armor package that completely protects the turret from rounds like the BM-26/29 but offers poor protection against rounds such as the Xm829. I would be surprised if the M833 and xm829 wasn't tested against armor packages proposed for this vehicle.

It could be (probably in my opinion also) that protection from mono block rounds was not a priority for the M1A1 that more advanced HEAT warheads was seen as the bigger threat.

"Later rounds such as the 3BM-42 "Mango" were/are tested against a seven-layered and a ten-layered special armour array as main targets." I have heard this but also heard it was a myth, that it was impossible for the the steel jacket encasing the two rods to behave in the way required (melting during the penetration process etc). If you have a source I would appreciate it, as I am confused on this issue.

The IMHO M833 is a better round then the Bm-42. Longer thicker heavier DU rod. Worse against steel but perhaps far better against complex targets.

http://i.imgur.com/TenM7Mn.jpg

In tests the DU and WU versions of the M833 were tested against complex targets. You can see that the DU version vastly out preforms the WU version against complex targets. I would love to know what the layout of " increased difficulty targets" was.

As for the M829, it does appear that Wiedzmin posted a picture of it next to some target blocks. It does appear it went through >600 mm of titanium which puts it in the ballpark of 550mm vs RHA. There is also RHA block bellow it.
https://i.imgur.com/DGMHkoTg.png

With regards to the Swedish test. I also would be surprised if the armor package of the M1A1HA (1988-90) out preforms the Swedish armor package vs KE. This makes sense, the often quoted armor values for the M1A1HA was 600mm vs KE. I strongly suspect this is from 30 deg. Which would place it between the American armor package and much newer Swedish one.


The Leopard 2 was designed to resist 105 mm smoothbore gun APFSDS ammo (simulating Soviet APFSDS rounds) despite mounting a 120 mm smoothbore gun - I know this is not an actual argument, but it shows that tanks are not designed to resist "round X" or "missile Y", just because the military of that country has "round X" and "missile Y" in its inventory. The M829 was probably tested against US special armour arrays, but that does not mean that the M1A1's armour array was meant to stop a M829 APFSDS (or that it was capable of doing so).

The statement regarding the steel sheat of the 3BM-42 APFSDS "melting" seems to be a mistranslation; it has been said that the steel sheat does not negatively impact the penetration of the tungsten penetrators (aside of resulting in a higher parasitic mass, I assume), which matches German statements regarding the 120 mm DM13 APFSDS, which was optimized to defeat multi-layered armour targets. Earlier APFSDS rounds with steel sheat such as the M735 APFSDS and the XM578 APFSDS (aswell as rounds such as the 125 mm 3BM-12, 3BM-15 and 3BM-17 rounds) had issues with this, because the steel sheat would impede yaw on the tungsten core, when being stripped away while penetrating a spaced steel plate.

As for the M833 DU and WHA variants: DU is/was a superior material in the 1970s and 1980s in more than just one way. Early tungsten heavy alloys had issues with fracturing, which is why the Germans and the Soviets kept steel sheats on their designs in 1979 (120 mm DM13) and 1985 (3BM-42 Mango). Seeing the US military testing a WHA variant of the M833 would therefore raise some questions regarding the alloy: maybe it was better than what the Germans and Soviets used, maybe it wasn't. If it was on the same level as the alloys used in Germany and the Soviet Union, that might explain why the performance gap between both rounds was so large and would imply, that (certain) steel sheated tungsten rounds might actually perform better in this case.
The M833 has a lot lower quoted armour penetration against RHA at least; Zaloga claims that some sources suggest a penetration of 420 mm LOS at 60° and 2,000 m range, but the German gun maker Rheinmetall uses quite a bit lower values (370-380 mm at 2,000 m) in one of its presentations regarding the merits of a 105 mm smoothbore gun. This also affects the M426 aka 105 mm DM63 (380 mm instead of the internet estimate of 450 mm) and M900 APFSDS (450 mm instead of 500-550 mm internet estimates) rounds, which are also quoted with a lower penetration. Given that the 3BM-42 Mango is claimed to achieve 460 mm at 60° and 2,000 m range (value taken from the official catalogue from Rosoboronexport), there might be quite a big difference in raw performance.Yes, the M833 (most likely) performs better against complex armour arrays, but the higher efficiency might not be enough to close the gap completely.

This is one of the special armour targets used in Russia. It has seven layers and therefore might be the seven-layered target defeated by the 3BM-42 Mango APFSDS, although I also have seen speculations regarding them refering to the hull armour arrays used on the T-72 tanks.
S76nTfV.jpgokMrTLq.jpg


As for the penetration of the M829: I don't think that matters, given that we have no confirmation that the M829 was used to test the armour of any Abrams variant and we also lack any information regarding the range and the used titanium alloy. While I personally would say the penetration depth into the titanium target is slightly below 600 mm (based on the size of the M829 projectile and perspective distortion), it really doesn't say much. Paul J. Hazell writes in "Armour: Materials, Theory, and Design" that the mass efficiency of titanium alloy armour ranges between 1.5 and 1.8 against DU APFSDS rounds, depending on alloy and projectile. That would mean the TE of military grade titanium alloys (if such were used) can be up to 14% lower than that RHA or up to equal. So without knowing anything about the specific material and the range, it doesn't really help us to determine the penetration capabilties of the M829 APFSDS.

 

The RHA block penetration photo that Wiedzmin posted is quite interesting. Small "bottleneck" entry channel leading to a larger penetration channel confirms without any trace of doubt that M829 has a pointed conical tip. Its performance at a high impact angle would be quite significantly worse than for a normal impact.

That would explain why M829 has only slightly better performance than M833 for Nato Heavy Single even though it has a much longer rod (512mm vs 427mm). 12.7 km vs 11.0 km is not a big difference for such a difference in length and velocity.


"Confirms without any trace of doubt"? Seriously?

m_nWHYjRl3g.jpg

mDDKe_xXBRI.jpg
(M829 penetrator is the third rod from the bottom)

Also your length data is incorrect, as I previously wrote currently available information suggest that the M829's penetrator has a total length of ~480 mm (~440 mm without threaded section for the fins).


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#72 methos

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Posted 21 March 2018 - 1551 PM

"more than 600" where ? Leo2A4 mantlet 420mm and weight only 630kg, it 100% better than soviet mantlet in terms of CE protection, but in case of KE, it will be penetrated by any 100-125mm APFSDS imho.
 
"gaps" are the same. more or less. in case of Leo2A4 again. whole right front part one big "gap"
 
i agree that the casted turrets have many problems with turret roof area.

 
Well, I said more modern than the T-80U, which is not the case with the Leopard 2A4. The Leopard 2A5 however has some 600 mm physical armour thickness at the manlet (even more at the upper half, which is also covered by an add-on plate):
lsRGMFH.jpg
 
The Leopard 2 armour upgrades from RUAG and Rheinmetall/IBD have even thicker armour at the gun mantlet.
Leopard-2-Evolution.jpg?fit=800%2C537
 
The K2 Black Panther, the Turkish Altay and the CATTB prototype all have gun shields reaching nearly the same thickness as the turret front armour, so it also should be within the 600-700 mm range. The new T-80BVM prototype keeps the same weak gun mantlet of the T-80U, while the T-90M seems to have a much better protected solution - this might not be related to the differences between cast and welded construction techniques, but is quite interesting.
 
t80bvm.jpgt90m.jpg

 

I think the SB armor model for the 1992 Leo-2A4 is given a 600mm vs KE value...He might be inferring it from that.
 
I would be interested in knowing the rational on some of the armor values. They have good access to data and Nils no doubt to takes these things rather seriously. The armor values were originally based on Paul Lakowski's work and have been updated more then a few times. I am not so sure the armor values in the diagrams represent what is currently in the game...
 
The 600mm vs KE seems a bit high.....I am sure they didn't just guess though, and I suspect they know more then I.

 
I was talking about physical thickness, not about armour protection levels. SteelBeasts' values are based on incorrect armour estimates combined with "good faith". I.e. the Leopard 2A4's mantlet armour is simulated as ceramic-steel-sandwich armour, but the SteelBeasts staff pretends that the trunnion block is made of military grade titanium alloy or high-hardened steel. This is counted as spaced armour, so instead of having 420 mm composite armour + a bit of mild steel, the Leopard 2A4 in SteelBeasts has 710 mm spaced + composite armour.


Edited by methos, 21 March 2018 - 1655 PM.

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#73 EasyE

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Posted 22 March 2018 - 0005 AM

 

We don't really know enough about the process for testing, replacing and implementing the armor packages (inserts etc) to speculate about how implementing even a minor upgrade would appear. For now we I think we have to accept we have the only most basic outline of what went on.

I find this interesting.

"Faced with this latest barrage of criticism, Chrysler Corporation has issued a bold challenge to its antagonists. "I'd be prepared to have them shoot anything they can find at the XM-1, including the latest Eastern bloc weapons," exclaims Louis Felder, manager of the XM-1 engineering program in Detroit. "We've done that and we've done that more than once."

"https://www.csmonito...21/112144.html"

I would be interested in knowing what they thought the latest eastern block weapons were. Or what was used as a stand in.


The statement by the Chrysler Corporation is typical marketing talk, I would consider this to be rather meaningless. BAE Systems, General Dynamics and PSM GmbH are all claiming that their respective IFV designs offer "best in class protection", yet all vehicles fall in the same weight class and there certainly are differences in the protection level.

Claims like "the latest Eastern bloc weapons" are silly, given that the United States military dramatically underestimated the penetration performance of Soviet ammunition. The report which mentions the "400 mm vs KE, 750 mm vs CE" protection level provided by "one version of the M1 turret armor" also includes US estimates of Soviet armour penetration:
epS7vp2.png

Soviet sources (with their stricter criteria for armour penetration!) mention that the 115 mm BM3 with tungsten carbide slug penetrates 270 mm steel armour at 2,000 m and the 125 mm 3BM-22 Zakolka penetrates 380 mm steel armour at 2,000 m.
 

As for the M1E1/M1A1.

https://encrypted-tb...Yx-BCPFvoCKVhAY

I disagree that the weight simulators don't cover the area protected. They do appear to cover the entire area of the inserts and be thicker then 1 inch each. Or there were various M1E1 weight simulators..I would be surprised BRL, spent over 8 years during the height of the cold war sitting on their hands not working on how to squeeze greater ME and TE out of armor designs. Do the inserts have harder steel, is there a ceramic layer, super hard shatter plate, ballistic aluminum back plate? Again we are trying to work backwards to get an answer that isn't even that relevant.


I have seen this photo of the M1E1 turret armour weight simulator plates, but unfortunately it shows only half the truth due to the perspective. If you look at other photos from other angles, you'll notice that the two steel plates are spaced (you can even see the weldlines for the spaces in your photo).

TxwqEAF.png

As for the coverage of the weight simulators...
LUh9dmD.pngQxg4e6P.png?1

The weight simulators cover a much smaller surface than the actual armour array should cover (we don't know if it does, but it really should...). Maybe the thickness of the plates is slightly higher or lower than one inch, but it seems to be rather close to this value. We also don't know if some of the simulated weight was used at places other than the frontal armour - maybe it was also used to simulate heavier protection elements in the side armour. It's a lot of speculation, but we don't have enough sources.

As for the protection provided by the enhanced Burlington armour, I remember having read a two page report about US armour development, where the Army came to the conclusion that it had underestimated the threat of KE rounds and not invested enough into the development of an armour array to protect against it, but new armour incorporating depleted uranium would address this issue. I will try to find it again.

The British military worked on Chobham armour for about 20 years before adopting it. Armour development takes time and a need for higher protection. If the protection level is sufficient against 115 mm APFSDS ammo and protection against 125 mm APFSDS cannot be achieved while staying at the desired weight, it is not really a priority to improve anti-KE performance. The biggest issue for the US military was apparently the low volume for special armour, which is why they went with depleted uranium - very good TE against KE ammo, but no the best ME. The CATTB shows an alternative development option - low density armour (without DU), but a much greater special armour thickness (specified to be either 1,000 or 1,200 mm) to provide a higher level of protection than the M1A1 HA.
 

Thinking in terms of RHA is the most basic starting point for understanding these types of armor packages. The M1E1 might have an armor package that completely protects the turret from rounds like the BM-26/29 but offers poor protection against rounds such as the Xm829. I would be surprised if the M833 and xm829 wasn't tested against armor packages proposed for this vehicle.

It could be (probably in my opinion also) that protection from mono block rounds was not a priority for the M1A1 that more advanced HEAT warheads was seen as the bigger threat.

"Later rounds such as the 3BM-42 "Mango" were/are tested against a seven-layered and a ten-layered special armour array as main targets." I have heard this but also heard it was a myth, that it was impossible for the the steel jacket encasing the two rods to behave in the way required (melting during the penetration process etc). If you have a source I would appreciate it, as I am confused on this issue.

The IMHO M833 is a better round then the Bm-42. Longer thicker heavier DU rod. Worse against steel but perhaps far better against complex targets.

http://i.imgur.com/TenM7Mn.jpg

In tests the DU and WU versions of the M833 were tested against complex targets. You can see that the DU version vastly out preforms the WU version against complex targets. I would love to know what the layout of " increased difficulty targets" was.

As for the M829, it does appear that Wiedzmin posted a picture of it next to some target blocks. It does appear it went through >600 mm of titanium which puts it in the ballpark of 550mm vs RHA. There is also RHA block bellow it.
https://i.imgur.com/DGMHkoTg.png

With regards to the Swedish test. I also would be surprised if the armor package of the M1A1HA (1988-90) out preforms the Swedish armor package vs KE. This makes sense, the often quoted armor values for the M1A1HA was 600mm vs KE. I strongly suspect this is from 30 deg. Which would place it between the American armor package and much newer Swedish one.


The Leopard 2 was designed to resist 105 mm smoothbore gun APFSDS ammo (simulating Soviet APFSDS rounds) despite mounting a 120 mm smoothbore gun - I know this is not an actual argument, but it shows that tanks are not designed to resist "round X" or "missile Y", just because the military of that country has "round X" and "missile Y" in its inventory. The M829 was probably tested against US special armour arrays, but that does not mean that the M1A1's armour array was meant to stop a M829 APFSDS (or that it was capable of doing so).

The statement regarding the steel sheat of the 3BM-42 APFSDS "melting" seems to be a mistranslation; it has been said that the steel sheat does not negatively impact the penetration of the tungsten penetrators (aside of resulting in a higher parasitic mass, I assume), which matches German statements regarding the 120 mm DM13 APFSDS, which was optimized to defeat multi-layered armour targets. Earlier APFSDS rounds with steel sheat such as the M735 APFSDS and the XM578 APFSDS (aswell as rounds such as the 125 mm 3BM-12, 3BM-15 and 3BM-17 rounds) had issues with this, because the steel sheat would impede yaw on the tungsten core, when being stripped away while penetrating a spaced steel plate.

As for the M833 DU and WHA variants: DU is/was a superior material in the 1970s and 1980s in more than just one way. Early tungsten heavy alloys had issues with fracturing, which is why the Germans and the Soviets kept steel sheats on their designs in 1979 (120 mm DM13) and 1985 (3BM-42 Mango). Seeing the US military testing a WHA variant of the M833 would therefore raise some questions regarding the alloy: maybe it was better than what the Germans and Soviets used, maybe it wasn't. If it was on the same level as the alloys used in Germany and the Soviet Union, that might explain why the performance gap between both rounds was so large and would imply, that (certain) steel sheated tungsten rounds might actually perform better in this case.
The M833 has a lot lower quoted armour penetration against RHA at least; Zaloga claims that some sources suggest a penetration of 420 mm LOS at 60° and 2,000 m range, but the German gun maker Rheinmetall uses quite a bit lower values (370-380 mm at 2,000 m) in one of its presentations regarding the merits of a 105 mm smoothbore gun. This also affects the M426 aka 105 mm DM63 (380 mm instead of the internet estimate of 450 mm) and M900 APFSDS (450 mm instead of 500-550 mm internet estimates) rounds, which are also quoted with a lower penetration. Given that the 3BM-42 Mango is claimed to achieve 460 mm at 60° and 2,000 m range (value taken from the official catalogue from Rosoboronexport), there might be quite a big difference in raw performance.Yes, the M833 (most likely) performs better against complex armour arrays, but the higher efficiency might not be enough to close the gap completely.

 

 

 

 

I think that there might be a few pictures floating around of different weight simulators on different tanks. Not sure but I suspect that they had a few packages with different weights they tested..To start the paint scheme on my photo is clearly different. In your photo that you added color to, it appears very clearly that the front plate is about as thick as the 50mm (or was it 70mm) side skirt while being further away from the camera. Despite also subject to prospective from the angles, the lower hull plate is considerably thinner then the thicker turret one. The bottom plate clearly has welds that give it relief from the main armor face. The second thicker plate I don't see it on one of the tanks to be honest.

 

I really do think we are looking at two different armor packages being tested here. The thickest RHA plate looks to me it could be as much as 75 mm but no less then 50mm.

The recent leaked document on the tank trials in Sweden states that the 1987 armor package on the Leo-2 is about 575mm vs KE head on (~840 LOS). It doesn't seem to me that big a stretch that the M1A1 with >900mm LOS would not have been somewhat comparable, I doubt better as I agree the USA did not take the threat of KE as much as the UK and Germany in the 1970s. If I am correct about the thickness of those weight simulators knowing nothing else about the armor design, it seems reasonable to me that the turret front could be 480-500mm vs contemporary APFSDS. Incorporating other improvements perhaps a little bit better. 

 

Perhaps the plates are perforated or there isn't any more steel in there at all. Perhaps it is simply 150-180mm of  ballistic aluminum added in front of the back plate and HHS shatter plate up front. That would be the cheaper stop gap option, which if you know you are developing a DU alloy based system a few years down the road, makes good sense. 180 mm of aluminum weighs about as much as 60mm or RHA IIRC. 


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#74 methos

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Posted 22 March 2018 - 0644 AM

I think that there might be a few pictures floating around of different weight simulators on different tanks. Not sure but I suspect that they had a few packages with different weights they tested..To start the paint scheme on my photo is clearly different. In your photo that you added color to, it appears very clearly that the front plate is about as thick as the 50mm (or was it 70mm) side skirt while being further away from the camera. Despite also subject to prospective from the angles, the lower hull plate is considerably thinner then the thicker turret one. The bottom plate clearly has welds that give it relief from the main armor face. The second thicker plate I don't see it on one of the tanks to be honest.
 
I really do think we are looking at two different armor packages being tested here. The thickest RHA plate looks to me it could be as much as 75 mm but no less then 50mm.
The recent leaked document on the tank trials in Sweden states that the 1987 armor package on the Leo-2 is about 575mm vs KE head on (~840 LOS). It doesn't seem to me that big a stretch that the M1A1 with >900mm LOS would not have been somewhat comparable, I doubt better as I agree the USA did not take the threat of KE as much as the UK and Germany in the 1970s. If I am correct about the thickness of those weight simulators knowing nothing else about the armor design, it seems reasonable to me that the turret front could be 480-500mm vs contemporary APFSDS. Incorporating other improvements perhaps a little bit better.
 
Perhaps the plates are perforated or there isn't any more steel in there at all. Perhaps it is simply 150-180mm of  ballistic aluminum added in front of the back plate and HHS shatter plate up front. That would be the cheaper stop gap option, which if you know you are developing a DU alloy based system a few years down the road, makes good sense. 180 mm of aluminum weighs about as much as 60mm or RHA IIRC.

 

There apparently were different prototypes with different weight simulators. We can keep arguing about the thickness of the weight simulators, wether they are spaced or mounted directly and what material they are made of, but we probably won't find the truth just from speculating. Maybe we'll find a better source or somebody manages to find one of the M1E1 prototypes and then measures the thickness of the steel plates. Personally I cannot agree with your statement regarding the thickness of the steel plates, because perspective and a spaced installation seem to play tricks.
 
Armour thickness is not a good metric for estimating protection levels, specficially when it comes down to estimated thickness values. We know that the Leopard 2 has 860 mm thick armour at the left turret front based on multiple measurements (i.e. measuring the distance from turret front to weldline, measuring the distance from the weldline to the hatch and measuring the distance from hatch to the steel plate inside the tank); the right turret front has a variable thickness: the upper portion is just 650 mm thick, the lower section has a thickness of 1,100 to 1,200 mm (but includes a huge gap for the electronics of the EMES-15 gunner's sight in the center). The values for the thickness of the M1A1's turret armour are pure estimates/guesses, which is a problem, given that such estimates have shown a high margin of error in the past.
The graphs from the Swedish test show us nothing about where the armour protection is achieved. My understanding is that it might show the protection along the frontal arc, rather than just the front surface; this could mean that the turret front achcieves the highest level of protection or maybe the side armour at a very narrow angle of impact - it doesn't say anything about where the armour protection is achieved. Your value of 575 mm vs KE for the Leopard 2A4 seems to be incorrect; according to the graph only 10% of the surface reach this protection level, while the frontal turret armour covers a greater portion of the total surface. It might be 500-540 mm (the protection achieved on 20 to 27% of the surface).
 

According to R. P. Hunnicutt, the M1 Abrams has a combat weight of 120,000 lbs (54.43 metric tons), while the M1 Improved Performance variant has a combat weight 122,000 lbs (55.33 metric tons). The M1IP is said to be identical to the M1A1 Abrams with the exception of the 120 mm M256 gun - it includes the heavier armour protection, the upgraded suspension and final drives, the new stowage rack, changes to the shock absorbers and the newer electronic systems - which would mean that the armour weight added with the M1IP/M1A1 upgrade is less than 900 kilograms.

The M1A1 weighs 55.79 metric tons with T156 tracks and ~58 tons with the T158 tracks. This pretty much makes 500-550 mm vs KE for the M1A1 turret impossible, because otherwise the DU armor package (~3,000 kg, all focused on the turret front) would be really, really ineffcient (i.e. it would provide the same protection as an armour package modification weighing less than 900 kg that is spread over a larger surface!). The Leopard 2A4 with original armour package ("C") has a weight of 55.15 metric tons, the Leopard 2A4 with new armour package weighed 56.5 metric tons. That's 1.35 metric tons spread over a smaller surface than on the M1A1. This brings me to the conclusion that the M1A1 armour upgrade was rather minor.

 

Sure, we could make up our own theories about how the armour looks like and then use this to explain some pre-defined assumptions regarding the protection level... but that doesn't seems very rational. Weight and thickness are only factors, not more and not less than that. The M1A1's protection level is idependent from the Leopard 2's, unless it is proven that both tanks were designed with the same requirements, have similar weight & volume alocated into armour protection and are making use of the same technology. As you can see in the previous discussion including the Soviet statements regarding the Leopard 2's armour technology and the patent from ISL, the actual armour layout might be quite a bit different. The Leopard 2A4 from 1988 is at least rumored to feature armour elements made of titanium and tungsten, which sounds a lot more like the armour package of the M1A1 HA and M1A2 tanks (at least the M1A2 SEP utilizes DU and titanum alloys in its armour array) rather than the M1A1 armour package designed prior 1984 (M1 Improved Performance entered service in October 1984). Your suggested M1A1 armour array seems like a rather bad design. Even ballistic grade aluminium provides very limited protection gain over steel armour (specifically the alloys available in the 1980s) in terms of weight, while the armour protection per thickness is even worse. Aluminium performs better against smaller penetrators; APFSDS rods are more useful at piercing it. As far as I know, the decision to adopt a DU armour array wasn't made when the development of the M1A1 variant began.


Edited by methos, 22 March 2018 - 1014 AM.

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#75 Interlinked

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Posted 22 March 2018 - 0835 AM

 

"Confirms without any trace of doubt"? Seriously?
 

 

Whoops, sorry, wrong thread. Actual photo posted by Wiedzmin doesn't show bottleneck anyway. I was referring to something else.


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