I found a book describing the composition of U.S Army M1A2 Abrams Armor package.
Maybe this data can be used for future M1A2 Abrams Appearance.
Hi, long time lurker here, first time posting. Just pointing out the very obvious here. The passage you cited says that 85% and 60% of the WEIGHT is RHA steel. That does not mean 85% and 60% of the thickness is RHA steel by simply multiplying the percentage of weight of RHA steel to get the thickness.
For example, imagine an armor array of 1000mm thickness with 1mm RHA front plate and 1mm RHA back plate with 998mm of air gap in between. In this case 100% of the weight is RHA steel (air has no weight,) but you can't just multiply that by the thickness of the armor array and say that it has 1000mm RHA steel.
Thanks, buddy. Appreciated for pointing out.
This would put hull armor weight at 2.6 tonnes and turret armor weight at 5.7 tonnes. It seems that this is the total special armor weight, rather than just the weight of the non-steel elements. I guess Mr. Crouch didn't have access to the exact layout of the armor, but only access to informations how much the empty steel shell with and without special armor modules weighs.
These figures lie within the expectations. The Swedish military reported that the M1A2 Abrams tank tested in Sweden (with a total combat weight of 62.5 tonnes) had less than 10 tonnes special armor weight.
Since the M1A2 will have titanium armor instead of steel, does that mean all the old M1 tanks made with integral steel armor won't be able to be upgraded to the M1A2 standard?
Well no, but for the reason the M1A2 uses a bigger turret than the original M1. As for the titanium, I don't think they replaced the steel structure with titanium; that would be expensive as hell, but they may have replaced non structural steel armor with titanium.
Wasn't the HAP armor previously described as steel-encased NERA arrays with DU backplates or interstitial DU meshing? Can't remember which piece of literature mentioned it or somewhat alluded to it (maybe DOE, not certain).
According to this presentation, the monolithic titanium armor is above the gunner's primary sight "doghouse," the blowoff panel covers, various and sundry covers for the NBC system, and "internal armor." None of those are integral to the vehicle hull.
I've read in a few places that some versions of the T-90 also use titanium NERA.
Both of these suggest that titanium alloys are efficient materials to use in NERA arrays. Why this should be eludes me. Titanium as a monolithic armor material is... rather mediocre.
B. I'd expect rather significantly larger weight savings, considering just how much of the weight of NERA is steel flyer plates.
While Titanium may have somewhat disappointing ballistic properties, it has excellent mechanical properties, and would be very useful in the mounting bracket application.
The only description I've seen of it that's verifiable is in the NRC license application, where it's described as "depleted Uranium encased in steel" and that says very little about the setup. I have a personal hypothesis on how it's set up, like several others, but it's purely conjecture.
^-- Also, the steel-encased part does not reveal whether they are talking about a fully-enclosed NERA package (with the steel possibly acting as shatter plate, unless they have DU front plates to fill that role) that's lowered into the armor cavities or if it merely refers to the cavity walls (the "outer skin" of the turret) being made of steel.
Wasn't the HAP armor previously described as steel-encased NERA arrays with DU backplates or interstitial DU meshing?
I don't think it ever has been described like that. It is just generally specified that the DU is "steel-encased" rather than at the exterior/interior surfaces of the tank; how it is used remains unknown (to me at least). However the British FVRDE apparently tested a version of NERA utilizing DU and polycarbonate interlayers.
While it is certainly possible that the T-90 might utilize titanium alloys as part of its armor array, is there any sort of source suggesting this aside of Paul's old "shot in the dark" estimates? IIRC he later claimed, that this estimation might be incorrect, because apparently light metals aren't very good in NERA.
That said, the Leclerc and Leopard 2A5 (at least the Swedish Strv 122) supposedly also utilize some titanium elements as part of their armor.
The 1,100 lb are the weight savings, not the weight of the titanium per se. How this weight saving is measured remains unknown (Is the armor array itself 1,100 lb lighter? Does it provide protection equivalent to a 1,100 lb heavier armor array?), thus making any predictions regarding what was replaced isn't really possible. How much NERA is there in the M1A2 Abrams before the SEP v2 upgrade? Was some of the NERA replaced by depleted uranium or other materials (High-hardness steel? Ceramics?)? We don't know.
I'd reckon that only a relatively small portion of the "almost 10 tons of special armor" are still NERA. The DU armor adds 1,995 kg to the tank (comparing weight of M1A1 and M1A1 HA with the same tracks), potentially a bit more in case of the M1A2. That leaves already at best 6.4 tonnes of NERA, if none of it was replaced by DU or other materials when trying to improve the efficiency of the armor against APFSDS rounds. Titanium doesn't seem to be suited to replace high-hardness steel.