Designing Around Production Issues

[LostCosmonaut]

Industrial considerations are a primary concern in AFV design; there's no point in designing a cool new tank if your factories can't actually build it. Therefore, the final design of an AFV is going to be a reflection of the builder's industrial capabilities; if your country can't do large scale castings, you're going to have a lot of welded parts, etc.This thread is intended for general discussion of the relationship between AFV design and industrial capacity; does method X produce a better part, and if it does, is it worth the added time and expense? If our country can't do Y, can we substitute Z to get an acceptable result?

 

example;

If I'm remembering correctly, it's quite difficult to produce thick armor plates of good quality. It seems like the use of sloped armor could help mitigate this; you can get the same LOS thickness while having a thinner plate, which might be easier to produce at a uniformly high quality than a thicker unsloped plate. Does this make sense?

[Priory_of_Sion]

Chieftain brings this point up in this video mainly about the engines. I wish he went into more detail why the Aussies used cast armor, but I assume it is along these lines. 

[Collimatrix]

example;

If I'm remembering correctly, it's quite difficult to produce thick armor plates of good quality. It seems like the use of sloped armor could help mitigate this; you can get the same LOS thickness while having a thinner plate, which might be easier to produce at a uniformly high quality than a thicker unsloped plate. Does this make sense?

 

Per Ogorkiewicz it's not even possible to make RHA thicker than 250mm or so, while triple hardness steel laminate is limited to 150mm thickness or so (at least as of the 1980s), so yes, you would need to slope it to get greater thickness.

[Belesarius]

I wonder what the best thickness of steel armor we could come up with today, using advance manufacturing techniques, and would the advanced composites we've come up with since be more effective?

[Priory_of_Sion]

I wonder what the best thickness of steel armor we could come up with today, using advance manufacturing techniques, and would the advanced composites we've come up with since be more effective?

Best thickness for what? 

[Belesarius]

Best thickness for what? 

Tank armor.

 

 Let me rephrase, given advances in metallurgy and manufacturing techniques, what is the best/thickest armor against known threats that  we can come up with, and is that even steel at this point? 

[Priory_of_Sion]

Tank armor.

 

 Let me rephrase, given advances in metallurgy and manufacturing techniques, what is the best/thickest armor against known threats that  we can come up with, and is that even steel at this point? 

Depends on what you want your tank to be able to do. 

 

Probably Chobham armor w/ DU(I don't know thickness - probably 200-400 mm) + ERA

[Collimatrix]

Tank armor.

 

 Let me rephrase, given advances in metallurgy and manufacturing techniques, what is the best/thickest armor against known threats that  we can come up with, and is that even steel at this point? 

 

 

If you mean most thickness efficient, the best armor for tanks right now is probably some sort of steel laminate.  Triple hardness steel is about 50% better than RHA for a given thickness and mass, making it one of the few armor technologies that beats RHA inch for inch.  It's a laminate of different types of steels with moderate hardness, high toughness steel sandwiching an extremely hard inner layer.  It's also a PITA to make.  There's lots of stuff that beats RHA pound for pound, but it's all very bulky (which is why modern tanks have such gigantic turrets).

 

As for the best armor period, it would definitely be some sort of array of different materials, not a homogeneous material.  Probably with ERA on the outside because that stuff is absurdly effective.

 

The underlying chassis will be steel or aluminum for structural reasons.  High-efficiency armor is not necessarily good building material.

 

One thing I want to know is why, if modern super-specialsauce armor is mostly NERA, are modern MBTs so expensive?  NERA is just polymers and steel, nothing too exotic.

[Bronezhilet]

Except that top of the line/specialised polymers are really really really expensive compared to your standard PE and PP.

[Bronezhilet]

Also, with metals you're limited to the heat transfer rate of said metal. Which, with steel, isn't all that high. I have some books on this which I should take a look at, it's been a while since I had a lecture on this.

 

But basically, due to the low heat transfer rate of steel you can't cool the core quick enough to lock the crystal structure in place. The crystal structure in steel when it's red-hot is quite strong/hard at room temperature, but if you let the metal cool on its own, the crystal structure changes and you end up with 'normal' steel. But you can keep that crystal structure if you cool it really really quickly. But since you can only cool the outer part quick enough, the crystal structure of the core changes, making it weaker.

 

For example, one of the brands of commercial 'armour'/wear resistant steel is Hardox. The top of the line Hardox plate (Hardox Extreme) with a HRC (Hardness Rockwell Cone) of 57-63 is only available with a maximum thickness of 19 mm. And just so you know, 65 HRC should be the absolute theoretical maximum hardness of steel.

[Bronezhilet]

It gets even worse when looking at actual commercial armour plates, Armox (same company). That stuff is available with a maximum thickness of an impressive 7.9 mm with a HRC of 58-63. So you go from 57-63 HRC to 58-63 HRC and your max thickness drops from 19 mm to 7.9 mm.

[Collimatrix]

The biggest concessions I can think of in AFV design are the powerplants with goofy things like the dual engines on the M3/M5/M24 family and of course the multibank.

[Sturgeon]

Anybody tried dual-hardness armor castings? Seems like that plus a generous helping of ERA would be a good way to make a cheap light/export tank with decent protection.

[T___A]

DAV mentions that the Soviet industry was incapable of mass producing the M-50T in the IS-7, which is odd given that the M-50T is simply a roided up V-2 with larger cylinder diameter.

[Collimatrix]

Anybody tried dual-hardness armor castings? Seems like that plus a generous helping of ERA would be a good way to make a cheap light/export tank with decent protection.

 

How would this work exactly?

[Belesarius]

How would this work exactly?

Yeah, I was wondering that too.