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18 hours ago, Scav said:

IIRC XM827 was supposed to be DU which at this point was probably superior due to alloys being better, might explain the difference?

 

The there were tungsten and DU versions of the XM827 during development, but the DU version was prefered in the end (still canceled in favor for the M829 though). Likewise the US Army tested WHA and DU versions of the XM833. The article from the ARMOR magazine doesn't mention any materials, but it also includes one mention of the M735A1 (with DU penetrator).

 

At the time, DU alloys could probably achieve better performance, but the 120 mm DM13 should be better than the M735 APFSDS and its M735A1 sub-variant, simply based on physics.

 

18 hours ago, Scav said:

Could you potentially give a link or something?

 

It is availabe on the website of the German patent office, the European patent office, Google patents and many more

 

https://worldwide.espacenet.com/publicationDetails/biblio?CC=DE&NR=2234219C1&KC=C1&FT=D#

 

18 hours ago, Scav said:

95% tungsten seems on the low end, would explain why they thought a more complex shape was necessary...

 

Actually it seems that modern tungsten heavy alloy penetrators are usually made with a slightly smaller tungsten content, in some cases as low as 90%. This way it is possible to create alloys with more ductility and/or strength.

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14 minutes ago, SH_MM said:

The there were tungsten and DU versions of the XM827 during development, but the DU version was prefered in the end (still canceled in favor for the M829 though). Likewise the US Army tested WHA and DU versions of the XM833. The article from the ARMOR magazine doesn't mention any materials, but it also includes one mention of the M735A1 (with DU penetrator).

 

At the time, DU alloys could probably achieve better performance, but the 120 mm DM13 should be better than the M735 APFSDS and its M735A1 sub-variant, simply based on physics.

Yeah, in that paper where they discuss the advantages of DU vs tungsten they include performance of DU and WHA XM774 and XM833 IIRC.

https://www.alternatewars.com/WW3/WW3_Documents/Military_Tech/TAS_107/Tank_Ammo_Sec_107_JUN-1980.pdf
Pg22

 

21 minutes ago, SH_MM said:

It is availabe on the website of the German patent office, the European patent office, Google patents and many more

Thanks!
I was hoping for some penetration or atleast % numbers of efficiency but I guess that was asking too much :/.

Still, good find!

 

48 minutes ago, SH_MM said:

Actually it seems that modern tungsten heavy alloy penetrators are usually made with a slightly smaller tungsten content, in some cases as low as 90%. This way it is possible to create alloys with more ductility and/or strength.

Huh, interesting, though such a thing is stated in the document I mentioned above, I just haven't seen any alloy specifics on the more modern penetrators.

Would a jacketed tungsten rod not partially solve the issue by using a steel jacket?

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1596568117_Challenger2vsM1A2.thumb.jpg.f

 

This is a snipplet from "Challenger 2 Main Battle Tank Owners' Workshop Manual: 1998 to Present" by Lt. Col. Dick Taylor of the RTR.

 

Apparently the M1A1 HA's DU armor results in about 15% better protection against APFSDS ammunition compared to the Challenger 2, but offers a lot lower protection against HEAT munitions. Given that the M1A1 HA's turret appears to have approximately 600-660 mm vs KE (estimated 30° arc and direct from the front), that would put the Challenger 2 at 510-560 mm vs KE (this figures would match the earlier documents form the Challenger 2 design phase asking for 500 mm vs KE on turret and hull). The Challenger 1 was designed to reach a protection level of 500 mm vs KE on turret and 275 mm vs KE on the upper hull front, but according to a footnote in the same book reached only 480 mm vs KE on the turret and 340 mm vs KE on the hull.

The Leopard 2 was apparently not only offered with the B armor configuration (as tested in the UK), but it was at least proposed with the C and D armor generations aswell (protection level of the latter armor type not being disclosed to the UK). It seems that the text on the right mentions protection figures in milimeters for the Leopard 2A4 with Type B and Type C armor configurations, but that is unfortunately cut off. The Leopard 2A4 (with Type B armor) was rejected for its poor armor, worse than the Chieftain with Stillbrew vs KE.

 

Does anybody have this book? I wonder if it is worth the read, because other snipplets I've seen seem to feature quite a lot of bias (i.e. tests of Challenger 2E in Greece).

 

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6 hours ago, SH_MM said:

Does anybody have this book? I wonder if it is worth the read, because other snipplets I've seen seem to feature quite a lot of bias (i.e. tests of Challenger 2E in Greece).

 

Good but not exceptional, the work is somewhat uneven, providing good details on the Omani Challenger 2 but very few about the engine and the ammunition, for example.

 

It's complementary to the book of Simon Dunstan.

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18 hours ago, SH_MM said:

1596568117_Challenger2vsM1A2.thumb.jpg.f

 

This is a snipplet from "Challenger 2 Main Battle Tank Owners' Workshop Manual: 1998 to Present" by Lt. Col. Dick Taylor of the RTR.

 

Apparently the M1A1 HA's DU armor results in about 15% better protection against APFSDS ammunition compared to the Challenger 2, but offers a lot lower protection against HEAT munitions. Given that the M1A1 HA's turret appears to have approximately 600-660 mm vs KE (estimated 30° arc and direct from the front), that would put the Challenger 2 at 510-560 mm vs KE (this figures would match the earlier documents form the Challenger 2 design phase asking for 500 mm vs KE on turret and hull). The Challenger 1 was designed to reach a protection level of 500 mm vs KE on turret and 275 mm vs KE on the upper hull front, but according to a footnote in the same book reached only 480 mm vs KE on the turret and 340 mm vs KE on the hull.

The Leopard 2 was apparently not only offered with the B armor configuration (as tested in the UK), but it was at least proposed with the C and D armor generations aswell (protection level of the latter armor type not being disclosed to the UK). It seems that the text on the right mentions protection figures in milimeters for the Leopard 2A4 with Type B and Type C armor configurations, but that is unfortunately cut off. The Leopard 2A4 (with Type B armor) was rejected for its poor armor, worse than the Chieftain with Stillbrew vs KE.

 

Does anybody have this book? I wonder if it is worth the read, because other snipplets I've seen seem to feature quite a lot of bias (i.e. tests of Challenger 2E in Greece).

 

according to most reliable sources M1A1HA / M1A2 have a protection of 600 mm in the frontal arc of 60 degrees.

this means that Challenger 1 and 2 has a protection of ~ 500 mm in a 60 ° frotal arc.

 

480 mm is if I correctly understood the speech about protection for special armor, which experienced for Challenger 1. But about the glacis a lot of questions. 275 mm probably without special armor. Ie just some steel plates. 340 mm probably with the "Light" Chebham version.

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1 hour ago, Clan_Ghost_Bear said:

What was the British rationale for not liking the ammo storage in the turret?

 

The Brits way the Brits modeled things, any non-kinetic parts of ammo that are hit are likely to kaboom and take out the machine, and so ignoring the fact that the ammo is separated in an armored compartment, ignoring that in frontal hits that the rear of the turret is the hardest thing to penetrate in a tank (as you have to punch through the *entire* turret) the Brits said that hull-bottom stowage for live ammo segments has the least chance of being hit. This is technically true comparing the amount of frontal area in which it is theoretically possible to hit the ammo, but this is ignoring the facts that the hull is less armored & that they can't separate off the ammo storage behind bulkheads with their stowage arrangement.

 

Due to the ammo separation it's virtually impossible to K-kill an Abrams by hitting the ammo, while a Chally 2 was K-killed when a friendly HESH shell hit an open hatch... and the blast detonated the hull ammo stowage.

 

TL;DR - The Brits judged purely by amount of frontal area ammo is stowed in, irrespective of how armored or safe that area is. By that logic, T-72s have the safest ammo stowage of any modern tank...

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On 11/27/2018 at 1:23 PM, SH_MM said:

The Challenger 1 was designed to reach a protection level of 500 mm vs KE on turret and 275 mm vs KE on the upper hull front, but according to a footnote in the same book reached only 480 mm vs KE on the turret and 340 mm vs KE on the hull.

Well, yes and no.

Spoiler

Afbeeldingsresultaat voor Challenger 1 protection

Challenger 1 in this case refers to the Challenger 1 and not Challenger 1 Mk 1 as a lot of people seem to think.

They say it's only able to stop T-72 tank rounds at ranges above 1km, now they supposedly rated the 125mm at 460mm DU and later in 1981 they rated the tungsten 125mm at 475mm.

Spoiler

pasted%20image%200%20(4)_a0ca159c91df075

I do have to point out how this table seems quite inaccurate or atleast inconsistent, even if it just refers to the hull armour, both the T-64 and T-72 reach higher than 270-290mm.

 

So, personally I'd put the turret more at around 470mm or so and the hull at 325 against WP ammo, against long rods.... it's going to be less than this.
 

On 11/27/2018 at 1:23 PM, SH_MM said:

The Leopard 2A4 (with Type B armor) was rejected for its poor armor, worse than the Chieftain with Stillbrew vs KE.

I've noticed that as well, they for some reason think the 2A4 was poorer armoured than the stillbrew chieftain, something I find quite funny.
The hull is obviously superior on the leo 2 and the turret especially in the frontal 60° is also superior or at the very least equal.
 

According to this page:

Spoiler

Image result for throw of the dice by stéphane mallarmé,accompanied by separate sheet with translation by anthony hartley, plate 12 in the portfolio shaped poetry (san francisco: arion press, 1981)

The stillbrew package in 1985 only managed to resist L23A1 (I assume it's L23A1, L23 is also possible) only at 1km, penetration for L23A1 according to another book (maybe the same one, but I think it's about the Challenger 1) is around 460mm.

So, ~450mm of KE protection at the tested spots isn't far off let alone superior to the 2A4's ~430mm which was achieved by firing what looks to be DM53 at it.

Spoiler

xNAFPmz.jpg

Right hand one was used for turret testing according to that slide and it looks an awful lot like DM53, the left one looks like DM33.

 

So, considering L23A1 is notably worse than DM53, I think it's safe to say it would  do worse against a 2A4 turret than DM53 and the protection given by the armour would "increase" as a result.
 

All of that is from a stricly frontal attack, the sides of a 2A4 are also fitted with spaced armour and the LOS of it would reach around 620-640mm if hit at a 30° angle.

The Stillbrew chieftain on the other hand ranges from ~160mm at the front corners to ~86mm at the flat turret sides, neither of these seem really better than what the 2A4 has to offer.

 

I also have to point out that it seems the Brits didn't realise that long rods actually perform better at angles than against flat armour, so to the left of the gun (from our POV) is only 120mm cast + ~60mm rubber + 125mm steel at 60°, which against a long rod won't perform as well as the right side which is 150mm cast + 60mm rubber + 150-215mm steel.

So in effect, the left side of the turret is quite a bit weaker than the right hand side despite probably having similar LOS values.

That's also why I consider the statement in the outer right column of that picture to be quite naive:
Reposted image for easier reading:

Spoiler

yOmGVG3.jpg

Quote

With it varying from 480mm to 540mm; however the final design was considered sufficient to stand a good chance of resisting the Soviet successor 125mm round (tungsten monobloc and sheathed staballoy, which was postulated as being able to penetrate around 530mm point blank).

So, despite their own round already penetrating it from 1km or so and the protection being quite inconsistent, they think it'll stop future 125mm long rod ammo?

L23A1 is already a little bit worse than 120mm DM23 in terms of raw performance, 3BM32 and 3BM42 I highly doubt will have any issue with this armour at most combat ranges.

So either they didn't think the Soviets couldn't make better ammo than they did, or they didn't understand that long rods perform better against sloped armour and LOS being equal doesn't translate to the afforded protection being equal.

 

Either case seems likely IMO, especially considering their track record of underestimating/misjudging Soviet ammunition.

 

 

Anyway, I think we need to stay critical even of their official documents as they seem to be wrong or inconsistent in quite a few cases.

 

3 minutes ago, TokyoMorose said:

TL;DR - The Brits judged purely by amount of frontal area ammo is stowed in, irrespective of how armored or safe that area is. By that logic, T-72s have the safest ammo stowage of any modern tank...

Yup, just like their preferance for not having a unitary sight, they seem to often come to the wrong practical conclusions.

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9 hours ago, Liberator said:

480 mm is if I correctly understood the speech about protection for special armor, which experienced for Challenger 1. But about the glacis a lot of questions. 275 mm probably without special armor.

 

The way the sentence mentioing this is phrased, the 480/340 mm are the actual protection achieved by the Challenger 1 tank with Chobham special armor. The 500/275 mm are the design goal from a time, when the Challenger 1 was still in development.

 

2 hours ago, Clan_Ghost_Bear said:

What was the British rationale for not liking the ammo storage in the turret?

 

If you read through this topic, there is a snipplet from a British report on the M1 Abrams (the M1 Abrams was considered as an alternative to the Challenger 1), which mentions that most of the initial tests with the "safe" ammo separation actually failed, apparently because the bulkhead was not strong enough to deal with the pressure in the split seconds before it was successfully lowered via the blow-off panels.

 

Other than that, the Abrams' turret ammo storage increases the frontal profile while at the same time requiring additional armor at the turret sides (due to the fact that such a large quantity of the total ammo load is located within a single place; one does not want a single RPG to take away essentially the complete ammo loadout of a MBT). The British - and the Germans - believed that putting more ammo in the well-protected frontal section of the hull was desirable.

 

1 hour ago, Scav said:

I do have to point out how this table seems quite inaccurate or atleast inconsistent, even if it just refers to the hull armour, both the T-64 and T-72 reach higher than 270-290mm. 

 

This is from the late 1970s, there was still quite a lot of development going on before the Shir 2 tank became the Challenger 1 (one difference being the improved turret armor of the latter), while NATO didn't know much about the Soviet tanks.

 

The hull of T-64 and T-72 were believed by the British to feature only 100 mm steel sloped at 68.5° as frontal armor (which is 272 mm steel along the line-of-sight), a major underestimation.

 

1 hour ago, Scav said:

I've noticed that as well, they for some reason think the 2A4 was poorer armoured than the stillbrew chieftain, something I find quite funny.

 

The statement about the Leopard 2's turret armor being worse than the Chieftain with Stillbrew is directly focused on frontal protection (i.e. when being hit straight on) against kinetic energy penetrators of the turret front. The Leopard 2 apparently has 400-450 mm (depending on location), with the gun mantlet potentially being worse armored (~350 mm; at least that seems to be the conlcusion of the analysis done by @Laviduce) - so the Chieftain with Stillbrew seems to be quite a bit better armored.

 

1 hour ago, Scav said:

So, ~450mm of KE protection at the tested spots isn't far off let alone superior to the 2A4's ~430mm which was achieved by firing what looks to be DM53 at it. 

  Reveal hidden contents

xNAFPmz.jpg

Right hand one was used for turret testing according to that slide and it looks an awful lot like DM53, the left one looks like DM33.

 

So, considering L23A1 is notably worse than DM53, I think it's safe to say it would  do worse against a 2A4 turret than DM53 and the protection given by the armour would "increase" as a result.
 

All of that is from a stricly frontal attack, the sides of a 2A4 are also fitted with spaced armour and the LOS of it would reach around 620-640mm if hit at a 30° angle.

 

The 120 mm DM53 APFSDS round did not exist at the time of the Swedish tests and certainly wasn't delivered to Sweden. The photograph most likely shows a test projectile made only for the evaluation.

 

The data for the Leopard 2 tanks apparently comes from Krauss-Maffei and likely does not reflect what Sweden was able to test (it would be very odd to let Sweden fire its APFSDS rounds and shaped charges at every possible armor package ever made for the Leopard 2, if they are only interested in the latest one(s)).

 

1 hour ago, Scav said:

So either they didn't think the Soviets couldn't make better ammo than they did, or they didn't understand that long rods perform better against sloped armour and LOS being equal doesn't translate to the afforded protection being equal.

 

The extract from the book regarding Chieftain''s armor already shows that the British underestimated the performance of Soviet rounds, it says that (in 1981) the penetration of the T-72's 125 mm gun was estimated to be 420 mm for steel penetrators and 475 mm for tungsten penetrators point-blank at normal (aka 0 meters, 90° impact angle). The United States also underestimated the performance of the Soviet 125 mm gun and ammunition, one could say they did that to an even greater extent.

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12 minutes ago, SH_MM said:

The 120 mm DM53 APFSDS round did not exist at the time of the Swedish tests and certainly wasn't delivered to Sweden. The photograph most likely shows a test projectile made only for the evaluation.

Well, it would've been a prototype if anything, but the similarity is too striking for it to be a coincidence, perhaps it was just a round with the same function and rough dimensions.
 

13 minutes ago, SH_MM said:

The data for the Leopard 2 tanks apparently comes from Krauss-Maffei and likely does not reflect what Sweden was able to test (it would be very odd to let Sweden fire its APFSDS rounds and shaped charges at every possible armor package ever made for the Leopard 2, if they are only interested in the latest one(s)).

If this is true, then I agree, but I don't know for sure.

 

14 minutes ago, SH_MM said:

The extract from the book regarding Chieftain''s armor already shows that the British underestimated the performance of Soviet rounds, it says that (in 1981) the penetration of the T-72's 125 mm gun was estimated to be 420 mm for steel penetrators and 475 mm for tungsten penetrators point-blank at normal (aka 0 meters, 90° impact angle). The United States also underestimated the performance of the Soviet 125 mm gun and ammunition, one could say they did that to an even greater extent.

Yep, it seems only Germany fully realised the 125mm potential (atleast looking at the Krapke threat diagram) although the leo 1 part probably isn't correct.

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10 minutes ago, Molota_477 said:

What page is the data of 480/340 on? 

 

I don't know, this is what I have read in another discussion on another website. As I said I don't own the book yet. I might have mistaken the values from a random discussion with a footnote from the book, which says that the Challenger 1 mounted armor providing "equivalent amounts" to 430 mm for the turret and 315 mm for the hull.

1187995418_Page1.thumb.jpg.8a19c7d83cb87

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3 minutes ago, SH_MM said:

 

I don't know, this is what I have read in another discussion on another website. As I said I don't own the book yet. I might have mistaken the values from a random discussion with a footnote from the book, which says that the Challenger 1 mounted armor providing "equivalent amounts" to 430 mm for the turret and 315 mm for the hull.

1187995418_Page1.thumb.jpg.8a19c7d83cb87

"Equivalent amount" might refer to the mass of special armor which mounted on MBT-80 and provide 480mm protection for turret and 430mm for front hull:

14662_2000.jpg

Note the endnote"6"

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24 minutes ago, Molota_477 said:

"Equivalent amount" might refer to the mass of special armor which mounted on MBT-80 and provide 480mm protection for turret and 430mm for front hull:

 

I don't think that it refers to mass of the special armor. Note that the following document seems to list the MBT-80 with "430 mm+" protection, while also listing the effective hull armor thickness of Centurion and Leopard 1 (implying that the figures for the other tanks might also be hull armor).

 

pasted%20image%200%20(4)_a0ca159c91df075

 

In documents from 1969 and 1970, it is already mentioned that Chobham armor has a mass efficiency of above 1.0, so 430 mm steel-equivalent mass should provide a noteworthy larger amount of armor protection. It also would be odd to mix figures in milimeters with tons (for the applique armor) without even specifying that the milimeters is meant to be steel-equivalent mass.

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14 minutes ago, SH_MM said:

steel-equivalent mass

Yes, I misread it before, so it makes sense that the ''up armour'' Challenger 1's turret can obtain up to 500mm protection against some specific KE rounds while the thickness of steel-equivalent mass only 430mm.I think the same theory also is appropriate for the glacis.

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6 hours ago, Molota_477 said:

14433_2000.jpg

 

It seems that the British documents use values for protection along the full 60° frontal arc.

 

The minimum thickness of the Leopard 2 turret cheek armor along the frontal arc is roughly 660 mm.

860/660*350 = 456 mm

860/660*420 = 547 mm

 

That matches the current interpretation of this graph from the Swedish documents:

kDGjKnO.png

 

Furthmore there is the statement about the M1A1 HA's DU armor providing 15° more protection than the Dorchester armor of the Challenger 2. Given that the former is believed to provide 600 mm protection vs KE along the frontal arc based on the Swedish documents (or about 660 mm from straight on assuming that the armor efficiency stays the same regardless of horizontal slope), this would put the Challenger 2 at 510 mm (560 mm head-on) vs KE. The protection requirement for the turret was armor equivalent to 500 mm steel vs KEPs (along the frontal arc?).

 

Even more so, the Brits believed the M1 Abrams to feature turret armor providing 340 mm equivalent protection vs KE along the frontal arc. That would be equivalent to 392 mm vs KE from head-on. A CIA document puts the M1 Abrams' turret at 400 mm vs KE.

 

 

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2 hours ago, SH_MM said:

 

It seems that the British documents use values for protection along the full 60° frontal arc.

 

The minimum thickness of the Leopard 2 turret cheek armor along the frontal arc is roughly 660 mm.

860/660*350 = 456 mm

860/660*420 = 547 mm

 

That matches the current interpretation of this graph from the Swedish documents:

 

 

Furthmore there is the statement about the M1A1 HA's DU armor providing 15° more protection than the Dorchester armor of the Challenger 2. Given that the former is believed to provide 600 mm protection vs KE along the frontal arc based on the Swedish documents (or about 660 mm from straight on assuming that the armor efficiency stays the same regardless of horizontal slope), this would put the Challenger 2 at 510 mm (560 mm head-on) vs KE. The protection requirement for the turret was armor equivalent to 500 mm steel vs KEPs (along the frontal arc?).

 

Even more so, the Brits believed the M1 Abrams to feature turret armor providing 340 mm equivalent protection vs KE along the frontal arc. That would be equivalent to 392 mm vs KE from head-on. A CIA document puts the M1 Abrams' turret at 400 mm vs KE.

 

 

Interesting, I think in the case of the Challenger it doesn't refer to added protection equivalent but actual LOS thickness of the entire package.

As for the number of the leopard 2, B seems more or less correct, not sure about C though, it's definitely interesting that it keeps coming back that C tech had this much added over the first variants, the weight increase doesn't seem like it would be enough, perhaps they managed this by using very "light" materials such as ceramics and replacing some steel with lighter alternatives?

Maybe they replaced the entire array and made it more efficient with higher hardness or something?

 

As for Challenger 2, it seems that in the Hellenic tank trials the tank was critisised for it's poor hull protection and lack of roof protection, similar to the Leclerc in terms of protection, so ~550 wouldn't seem too far off, it's definitely worse than the M1A2 and leopard 2A5 as suggested.

 

I still need to find the original magazine where they talk about the trials though.

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The Greek article on the trials is just two pages long and doesn't go into detail about armor protection other than saying that the Leopard 2A5 had the best, followed by the M1A2 Abrams and that the Challenger 2's armor was disappointing, being merely better than the Leclerc. The CR2 features improved roof armor over the Challenger 1, it should be better than the Leclerc and Abrams in this regard.

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On 11/29/2018 at 12:59 AM, SH_MM said:

 

I don't think that it refers to mass of the special armor. Note that the following document seems to list the MBT-80 with "430 mm+" protection, while also listing the effective hull armor thickness of Centurion and Leopard 1 (implying that the figures for the other tanks might also be hull armor).

 

pasted%20image%200%20(4)_a0ca159c91df075

 

In documents from 1969 and 1970, it is already mentioned that Chobham armor has a mass efficiency of above 1.0, so 430 mm steel-equivalent mass should provide a noteworthy larger amount of armor protection. It also would be odd to mix figures in milimeters with tons (for the applique armor) without even specifying that the milimeters is meant to be steel-equivalent mass.

Finally I found the document of GSR3572, the data of 480 and 430 only refer to the KE protection, but not the mass equivalent thickness, and there is a heaviest protection level up to 540mm.(But it is so heavy and very hard to offer full protection on hull under MLC70, while MLC60 or 55 tonnes only is a basic model without full protection on hull, note "full protection" means including side protecion within a limited angle. 

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12 hours ago, Molota_477 said:

Finally I found the document of GSR3572, the data of 480 and 430 only refer to the KE protection, but not the mass equivalent thickness, and there is a heaviest protection level up to 540mm.(But it is so heavy and very hard to offer full protection on hull under MLC70, while MLC60 or 55 tonnes only is a basic model without full protection on hull, note "full protection" means including side protecion within a limited angle. 

However, apparently this has little to do with Challenger 1. 

MBT-80 looks very promising, sad that the British could not start it in production.

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2 hours ago, Liberator said:

However, apparently this has little to do with Challenger 1. 

MBT-80 looks very promising, sad that the British could not start it in production.

Yes , the GSR 3572 only for MBT-80, so that's all I mean.

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59 minutes ago, Liberator said:

540 mm Hull and turret or only turret? And what CE protection MBT-80?

 

Both hull(full protection, including front arc of 50°) and turret at 69 metric tonnes.

While combat weight at 64 tonnes——fully protected turret + hull protection without enough side armor(only front glacis).

 

The number of 540mm actually meams a specific KE threat which could penetrate up to 540mm RHA at 1km range(It was assumed as Soviet DU APFSDS M1980). MBT-80's Chobham armour was desired to defeat such threat after some meetings in 1978.

 

Besides these two heaviest schemes, there are also 2 correspondly intermedial schemes have 480mm protection level, but still too heavy, the full protection scheme weight 65 t, and the "only front protection on hull" version weight 62 t.

 

Note that all of these schemes are only on paper discussion.

 

And the level of 430mm RHA actually is the original requirement for MBT-80 before 1978. They thought it can be achieved within MLC60 which the turret is fully protected while the hull only has upper glacis.

 

As for CE threat, they specified the need of againsting 130mm caliber shape charge(also is front ±25° in azimuth).

 

That's all I have seen.

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1 hour ago, Molota_477 said:

 

Both hull(full protection, including front arc of 50°) and turret at 69 metric tonnes.

While combat weight at 64 tonnes——fully protected turret + hull protection without enough side armor(only front glacis).

 

The number of 540mm actually meams a specific KE threat which could penetrate up to 540mm RHA at 1km range(It was assumed as Soviet DU APFSDS M1980). MBT-80's Chobham armour was desired to defeat such threat after some meetings in 1978.

 

Besides these two heaviest schemes, there are also 2 correspondly intermedial schemes have 480mm protection level, but still too heavy, the full protection scheme weight 65 t, and the "only front protection on hull" version weight 62 t.

 

Note that all of these schemes are only on paper discussion.

 

And the level of 430mm RHA actually is the original requirement for MBT-80 before 1978. They thought it can be achieved within MLC60 which the turret is fully protected while the hull only has upper glacis.

 

As for CE threat, they specified the need of againsting 130mm caliber shape charge(also is front ±25° in azimuth).

 

That's all I have seen.

Yes, I read about this before.
It is interesting that for 130 mm CE. I know the parameters of 5 and 6 inch CE for testing, but for the first time I hear about 130 mm.

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    • By N-L-M
      Restricted: for Operating Thetan Eyes Only

      By order of Her Gracious and Serene Majesty Queen Diane Feinstein the VIII

      The Dianetic People’s Republic of California

      Anno Domini 2250

      SUBJ: RFP for new battle tank

      1.      Background.
      As part of the War of 2248 against the Perfidious Cascadians, great deficiencies were discovered in the Heavy tank DF-1. As detailed in report [REDACTED], the DF-1 was quite simply no match for the advanced weaponry developed in secret by the Cascadian entity. Likewise, the DF-1 has fared poorly in the fighting against the heretical Mormonhideen, who have developed many improvised weapons capable of defeating the armor on this vehicle, as detailed in report [REDACTED]. The Extended War on the Eastern Front has stalled for want of sufficient survivable firepower to push back the Mormon menace beyond the Colorado River south of the Vegas Crater.
      The design team responsible for the abject failure that was the DF-1 have been liquidated, which however has not solved the deficiencies of the existing vehicle in service. Therefore, a new vehicle is required, to meet the requirements of the People’s Auditory Forces to keep the dream of our lord and prophet alive.


       
      Over the past decade, the following threats have presented themselves:

      A.      The Cascadian M-2239 “Norman” MBT and M-8 light tank

      Despite being approximately the same size, these 2 vehicles seem to share no common components, not even the primary armament! Curiously, it appears that the lone 120mm SPG specimen recovered shares design features with the M-8, despite being made out of steel and not aluminum like the light tank. (based on captured specimens from the battle of Crater Lake, detailed in report [REDACTED]).
      Both tanks are armed with high velocity guns.

      B.      The Cascadian BGM-1A/1B/1C/1D ATGM

      Fitted on a limited number of tank destroyers, several attack helicopters, and (to an extent) man-portable, this missile system is the primary Cascadian anti-armor weapon other than their armored forces. Intelligence suggests that a SACLOS version (BGM-1C) is in LRIP, with rumors of a beam-riding version (BGM-1D) being developed.

      Both warheads penetrate approximately 6 cone diameters.

      C.      Deseret tandem ATR-4 series
      Inspired by the Soviet 60/105mm tandem warhead system from the late 80s, the Mormon nation has manufactured a family of 2”/4” tandem HEAT warheads, launched from expendable short-range tube launchers, dedicated AT RRs, and even used as the payload of the JS-1 MCLOS vehicle/man-portable ATGM.
      Both warheads penetrate approximately 5 cone diameters.

      D.      Cascadian HEDP 90mm rocket
      While not a particularly impressive AT weapon, being of only middling diameter and a single shaped charge, the sheer proliferation of this device has rendered it a major threat to tanks, as well as lighter vehicles. This weapon is available in large numbers in Cascadian infantry squads as “pocket artillery”, and there are reports of captured stocks being used by the Mormonhideen.
      Warhead penetrates approximately 4 cone diameters.

      E.      Deseret 40mm AC/ Cascadian 35mm AC
      These autocannon share broadly similar AP performance, and are considered a likely threat for the foreseeable future, on Deseret armored cars, Cascadian tank destroyers, and likely also future IFVs.

      F.      IEDs

      In light of the known resistance of tanks to standard 10kg anti-tank mines, both the Perfidious Cascadians and the Mormonhideen have taken to burying larger anti-tank A2AD weaponry. The Cascadians have doubled up some mines, and the Mormons have regularly buried AT mines 3, 4, and even 5 deep.

      2.      General guidelines:

      A.      Solicitation outline:
      In light of the differing requirements for the 2 theaters of war in which the new vehicle is expected to operate, proposals in the form of a field-replaceable A-kit/B-kit solution will be accepted.

      B.      Requirements definitions:
      The requirements in each field are given in 3 levels- Threshold, Objective, and Ideal.
      Threshold is the minimum requirement to be met; failure to reach this standard may greatly disadvantage any proposal.

      Objective is the threshold to be aspired to; it reflects the desires of the People’s Auditory Forces Armored Branch, which would prefer to see all of them met. At least 70% must be met, with bonus points for any more beyond that.

      Ideal specifications are the maximum of which the armored forces dare not even dream. Bonus points will be given to any design meeting or exceeding these specifications.

      C.      All proposals must accommodate the average 1.7m high Californian recruit.

      D.      The order of priorities for the DPRC is as follows:

      a.      Vehicle recoverability.

      b.      Continued fightability.

      c.       Crew survival.

      E.      Permissible weights:

      a.      No individual field-level removable or installable component may exceed 5 tons.

      b.      Despite the best efforts of the Agriculture Command, Californian recruits cannot be expected to lift weights in excess of 25 kg at any time.

      c.       Total vehicle weight must remain within MLC 120 all-up for transport.

      F.      Overall dimensions:

      a.      Length- essentially unrestricted.

      b.      Width- 4m transport width.

                                                                    i.     No more than 4 components requiring a crane may be removed to meet this requirement.

                                                                   ii.     Any removed components must be stowable on top of the vehicle.

      c.       Height- The vehicle must not exceed 3.5m in height overall.

      G.     Technology available:

      a.      Armor:
      The following armor materials are in full production and available for use. Use of a non-standard armor material requires permission from a SEA ORG judge.
      Structural materials:

                                                                    i.     RHA/CHA

      Basic steel armor, 250 BHN. The reference for all weapon penetration figures, good impact properties, fully weldable. Available in thicknesses up to 150mm (RHA) or 300mm (CHA).
      Density- 7.8 g/cm^3.

                                                                   ii.     Aluminum 5083

      More expensive to work with than RHA per weight, middling impact properties, low thermal limits. Excellent stiffness.

       Fully weldable. Available in thicknesses up to 100mm.
      Mass efficiency vs RHA of 1 vs CE, 0.9 vs KE.
      Thickness efficiency vs RHA of 0.33 vs CE, 0.3 vs KE.
      Density- 2.7 g/cm^3 (approx. 1/3 of steel).

      For structural integrity, the following guidelines are recommended:

      For light vehicles (less than 40 tons), not less than 25mm RHA/45mm Aluminum base structure

      For heavy vehicles (70 tons and above), not less than 45mm RHA/80mm Aluminum base structure.
      Intermediate values for intermediate vehicles may be chosen as seen fit.
      Non-structural passive materials:

                                                                  iii.     HHA

      Steel, approximately 500 BHN through-hardened. Approximately twice as effective as RHA against KE and HEAT on a per-weight basis. Not weldable, middling shock properties. Available in thicknesses up to 25mm.
      Density- 7.8g/cm^3.

                                                                  iv.     Glass textolite

      Mass efficiency vs RHA of 2.2 vs CE, 1.64 vs KE.

      Thickness efficiency vs RHA of 0.52 vs CE, 0.39 vs KE.
      Density- 1.85 g/cm^3 (approximately ¼ of steel).
      Non-structural.

                                                                   v.     Fused silica

      Mass efficiency vs RHA of 3.5 vs CE, 1 vs KE.

      Thickness efficiency vs RHA of 1 vs CE, 0.28 vs KE.
      Density-2.2g/cm^3 (approximately 1/3.5 of steel).
      Non-structural, requires confinement (being in a metal box) to work.

                                                                  vi.     Fuel

      Mass efficiency vs RHA of 1.3 vs CE, 1 vs KE.

      Thickness efficiency vs RHA of 0.14 vs CE, 0.1 vs KE.

      Density-0.82g/cm^3.

                                                                vii.     Assorted stowage/systems

      Mass efficiency vs RHA- 1 vs CE, 0.8 vs KE.

                                                               viii.     Spaced armor

      Requires a face of at least 25mm LOS vs CE, and at least 50mm LOS vs KE.

      Reduces penetration by a factor of 1.1 vs CE or 1.05 vs KE for every 10 cm air gap.
      Spaced armor rules only apply after any standoff surplus to the requirements of a reactive cassette.

      Reactive armor materials:

                                                                  ix.     ERA-light

      A sandwich of 3mm/3mm/3mm steel-explodium-steel.
      Requires mounting brackets of approximately 10-30% cassette weight.

      Must be spaced at least 3 sandwich thicknesses away from any other armor elements to allow full functionality. 81% coverage (edge effects).

                                                                   x.     ERA-heavy

      A sandwich of 15mm steel/3mm explodium/9mm steel.
      Requires mounting brackets of approximately 10-30% cassette weight.
      Must be spaced at least 3 sandwich thicknesses away from any other armor elements to allow full functionality. 81% coverage (edge effects).

                                                                  xi.     NERA-light

      A sandwich of 6mm steel/6mm rubber/ 6mm steel.
      Requires mounting brackets of approximately 10-30% cassette weight.
      Must be spaced at least 1 sandwich thickness away from any other armor elements to allow full functionality. 95% coverage.

                                                                 xii.     NERA-heavy

      A sandwich of 30mm steel/6m rubber/18mm steel.
      Requires mounting brackets of approximately 10-30% cassette weight.
      Must be spaced at least 1 sandwich thickness away from any other armor elements to allow full functionality. 95% coverage.

      The details of how to calculate armor effectiveness will be detailed in Appendix 1.

      b.      Firepower

                                                                    i.     2A46 equivalent tech- pressure limits, semi-combustible cases, recoil mechanisms and so on are at an equivalent level to that of the USSR in the year 1960.

                                                                   ii.     Limited APFSDS (L:D 15:1)- Spindle sabots or bourelleted sabots, see for example the Soviet BM-20 100mm APFSDS.

                                                                  iii.     Limited tungsten (no more than 100g per shot)

                                                                  iv.     Californian shaped charge technology- 5 CD penetration for high-pressure resistant HEAT, 6 CD for low pressure/ precision formed HEAT.

                                                                   v.     The general issue GPMG for the People’s Auditory Forces is the PKM. The standard HMG is the DShK.

      c.       Mobility

                                                                    i.     Engines tech level:

      1.      MB 838 (830 HP)

      2.      AVDS-1790-5A (908 HP)

      3.      Kharkov 5TD (600 HP)

                                                                   ii.     Power density should be based on the above engines. Dimensions are available online, pay attention to cooling of 1 and 3 (water cooled).

                                                                  iii.     Power output broadly scales with volume, as does weight. Trying to extract more power from the same size may come at the cost of reliability (and in the case of the 5TD, it isn’t all that reliable in the first place).

                                                                  iv.     There is nothing inherently wrong with opposed piston or 2-stroke engines if done right.

      d.      Electronics

                                                                    i.     LRFs- unavailable

                                                                   ii.     Thermals-unavailable

                                                                  iii.     I^2- limited

      3.      Operational Requirements.

      The requirements are detailed in the appended spreadsheet.

      4.      Submission protocols.

      Submission protocols and methods will be established in a follow-on post, nearer to the relevant time.
       
      Appendix 1- armor calculation
      Appendix 2- operational requirements
       
      Good luck, and may Hubbard guide your way to enlightenment!
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