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VertigoEx

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About VertigoEx

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  1. 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.
  2. 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.
  3. 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.
  4. 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.
  5. You are correct I measured just to the mounting bracket on the top end, Looking at my picture I see the error now. 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. 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. 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.
  6. 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.
  7. 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?
  8. 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. 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.
  10. 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.
  11. 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. 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.
  12. Almost certainly this is the case. 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. 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.
  13. 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?
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