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Chieftain Questions


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More Chieftain datasheets (but in Swedish - translation is left as an exercise for the reader): http://imgur.com/a/620DL

Note the dates in the upper right corner - May 1961, December 1961, September 1963 in that order.

 

thanks! turret front:

 

v1- 120mm/30 degree

v2- 150mm/30 degree

v3- 300mm/55 ?

 

hull front have two value (some turrets also have two)? upper and lower ?

v1- upper 90mm lower 90mm

v2- upper 80mm lower 90mm

v3- upper 80mm lower 76mm

wVGxr1ux48w.jpg

Edited by Wiedzmin
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My impression was always that it was a counter for fin; the part the rubber played in the mechanism has always eluded me. We were told that it was one shot protection and that we should expect it to fall off after being struck.

Thats interesting, id not heard that. Was that what you were told when you were using them?

 

Maybe the Rubber was just a means of providing a gap between the metal plates?

 

Yeah we were told it was a direct response to the Russian fin rounds used against Iranian Chieftain. Stands to reason; high hardness steel to blunt a kinetic round. It's not plates Stuart, the rubber sheets are one on top of the other without anything between and then a big chunk of steel on the outside. The array was supported by stainless steel rods and the nuts on the end were torqued down with considerable force to create the final sandwich. I'm sure they knew what they were doing, within very tight budget limits, but I still don't 100% get the principle.

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Guest Jason L

It's a form of bulging armor guys, although I feel like the heavy front case, and only single metal-rubber-metal sandwich might not make it the most efficient implementation of the concept.

 

Ideally the rubber (or whatever plastic) undergoes poisson expansion from the compression/shock of the penetrator impact, and this bulges up the steel layer into the path of the penetrator, which feeds more los material, induces yaw and laterial loads.

 

Works against both rods and shaped charges. I've always maintained the concept works better vs jets than versus rods just because the impact pressures are higher and so the bulging is more pronounced, and jets are generally more vulnerable to being broken up from laterial loads.

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I'd expect that the forward armour piece is way too heavy as a monolithic piece to be useful in that regard, Jason, but you're better placed to understand the energies involved, I guess.

 

Personally I'd suggest something more mundane - directly mounting a heavy slab of armour onto the front face with bolts without some kind of shock-absorbing layer might result in the slab shearing the bolts over rough terrain.As for why 6 layers - well, it's cheaper to make six flat pieces and allow them to shape themselves over the turret form than it would be to mould a single thick piece (which wouldn't fit anything other than the one they took the initial mould from anyway, given the UK's legendary manufacturing tolerances.)

 

Just an alternative suggestion, you understand :D

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It's a form of bulging armor guys, although I feel like the heavy front case, and only single metal-rubber-metal sandwich might not make it the most efficient implementation of the concept.

 

Ideally the rubber (or whatever plastic) undergoes poisson expansion from the compression/shock of the penetrator impact, and this bulges up the steel layer into the path of the penetrator, which feeds more los material, induces yaw and laterial loads.

 

Works against both rods and shaped charges. I've always maintained the concept works better vs jets than versus rods just because the impact pressures are higher and so the bulging is more pronounced, and jets are generally more vulnerable to being broken up from laterial loads.

For a minute there I thought we were talking about fish,Poisson http://en.wikipedia.org/wiki/Poisson_distribution

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If it was for HEAT then they would have just used ERA; there were kits for Ch1 and Warrior, the latter being considered too dangerous for the (turret) crew, so never fielded.

 

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Guest Jason L

 

It's a form of bulging armor guys, although I feel like the heavy front case, and only single metal-rubber-metal sandwich might not make it the most efficient implementation of the concept.

 

Ideally the rubber (or whatever plastic) undergoes poisson expansion from the compression/shock of the penetrator impact, and this bulges up the steel layer into the path of the penetrator, which feeds more los material, induces yaw and laterial loads.

 

Works against both rods and shaped charges. I've always maintained the concept works better vs jets than versus rods just because the impact pressures are higher and so the bulging is more pronounced, and jets are generally more vulnerable to being broken up from laterial loads.

For a minute there I thought we were talking about fish,Poisson http://en.wikipedia.org/wiki/Poisson_distribution

 

 

Same Poisson, different math/physics.

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If it was for HEAT then they would have just used ERA; there were kits for Ch1 and Warrior, the latter being considered too dangerous for the (turret) crew, so never fielded.

 

 

Google says ROMOR-A. That is a totally new one on me, albeit it's a model!

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Guest Jason L

I'd expect that the forward armour piece is way too heavy as a monolithic piece to be useful in that regard, Jason, but you're better placed to understand the energies involved, I guess.

 

Personally I'd suggest something more mundane - directly mounting a heavy slab of armour onto the front face with bolts without some kind of shock-absorbing layer might result in the slab shearing the bolts over rough terrain.As for why 6 layers - well, it's cheaper to make six flat pieces and allow them to shape themselves over the turret form than it would be to mould a single thick piece (which wouldn't fit anything other than the one they took the initial mould from anyway, given the UK's legendary manufacturing tolerances.)

 

Just an alternative suggestion, you understand :D

 

Well, I mean yes and no. The plates in NERA don't expand like rigid bodies subject to F=ma just because the local pressures are so high, but thinner plates are evidently better since you get the expansion wave effects from the front surface quicker.

 

The thing is, if you've got it bolted to the front, and from all the pics that looks to be some really serious bolting, the whole thing is going to be too rigid to really benefit from shock absorbing.

 

Another option is simply that the addition of that big steel piece, plus the rubber added sufficient protection on top of the base armor to defeat the threats in question. Confined rubber just behaving statically isn't terrible protection afterall.

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IIRC external layer of Stillbrew was just sheet metal says Bob (I remember picking his brain about it) for cosmetic purposes. IIRC there was a space between the rubber layer and the turret.

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Google says ROMOR-A. That is a totally new one on me, albeit it's a model!

 

Royal Ordnance's ROMOR-A explosive reactive armor was also used by the FV4030/4 Challenger 1 during Gulf War and KFOR peacekeeping mission in Kosovo.

 

http://www.army-guide.com/eng/product3884.html

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IIRC external layer of Stillbrew was just sheet metal says Bob (I remember picking his brain about it) for cosmetic purposes. IIRC there was a space between the rubber layer and the turret.

There was a cosmetic shroud around the whole thing; there were points where ceramic fill could be injected. The rubber was laid directly onto the turret; I watched the process at 23 base Workshops.

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Google says ROMOR-A. That is a totally new one on me, albeit it's a model!

 

Royal Ordnance's ROMOR-A explosive reactive armor was also used by the FV4030/4 Challenger 1 during Gulf War and KFOR peacekeeping mission in Kosovo.

 

http://www.army-guide.com/eng/product3884.html

 

Yeah, we got told it's name when they fitted it to the Challengers in gulf 1; just never knew there was a Chieftain kit.

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Guest Jason L

 

IIRC external layer of Stillbrew was just sheet metal says Bob (I remember picking his brain about it) for cosmetic purposes. IIRC there was a space between the rubber layer and the turret.

There was a cosmetic shroud around the whole thing; there were points where ceramic fill could be injected. The rubber was laid directly onto the turret; I watched the process at 23 base Workshops.

 

 

So there is a one piece cast metal covering that goes over all of the different cheek pieces? How many cheek segments are there? 4?

 

How do you "inject" ceramic fill? Just dump in balls?

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There was a cosmetic shroud around the whole thing; there were points where ceramic fill could be injected. The rubber was laid directly onto the turret; I watched the process at 23 base Workshops.

What was the purpose of the ceramic ? :huh:

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@Jason L./Sovngard The cosmetic plate was not one piece; you could see weld marks, some parts sounded more hollow than others. Can't remember the number of steel pieces; pretty sure it was more than 4. Ceramic fill is liquid and forced in under pressure, presume it's a bit like Liquid Armour™ :D

Edited by jmcmtank
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