Right but we’re talking some 10mm of protection. From the various slabs.
10mm for a for example 83mm penetrating bullet is around 13% That is a bigger number than it seems
That’s not what the STANAG rating describes.
Right but its not the bulk of the protection afforded to a KE impact, that’s the composite layers.
1st - it’s the over all width of the lower armour 200mm plus it has a 40mm backplate
2nd - it 40mm RHA + 200mm block
ASPRO-HMT (Hybrid MTAP) is layered, with repeating tiles of passive and reactive elements. The reactive elements do nothing in KE. Ignore them. The passive is the KE defence for this armor.
When shooting between -30 and +30 degrees, follow the orange lines and you can see it will engage every tile. This is the maximum protection ASPRO provides kinetically.
Now if we increase the angle and fire a projectile at it, we miss a large portion of the tiles at the back. This invalidates the test as you have not engaged the entire strike face in the attack, hence why there is a -30 to +30 cone restriction. You must be testing relatively head on, to hit only the intended impact surface of ASPRO. Not the sides or corners or back.
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Obviously chobham tiles will do better angled, but we are not engaging as many chobham tiles as the angle increases, actually harming the protection.
Mate I’m sorry I remain unconvinced. The spec for level 5 is the front arc of the vehicle “including the sides” its not the front arc of the armour in whatever place you put it. That means its the front armour and whatever side armour might be within the arc.
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So how exactly is firing at the ASPRO-HMT, at a 60 degree impact angle (roughly 30 degree heading), where only a very small portion of the total brick is engaged, anywhere close to being representative of the entire bricks KE resistance?
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One of these tests engages the entire block and gives an accurate indication of the maximum performance ASPRO-HMT can reach.
The other test gives no indication of maximum values because you’ve only shot through a small portion of the panel??
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and you cant even claim its 2 blocks added together as one of your previous sources says they test the blocks individually
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The tests state centreline, not strikeface.
So you’ve got to be firing at the center of mass for the brick not the bricks front. Maybe this is where you’ve become confused?
Which then by that metric arent the Blocks still failing to meet their requirements as they cant stop 14.5 on their own (only with 2 blocks)
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A frontal arc to the centreline of the panel would be the cone I showed.
Your diagram is not representative of the tests as it would no longer be a frontal arc.
No even on your diagram at 60 degree toward the frontal arc the 25mm APFSDS only has some 48mm of penetration.
There would only need to be 48mm of material in the block to stop the round at that angle.
48mm might be better than 30mm
if the block is filled front to back, then I can pretty guaratee if you measured it as per your last diagram there is some ~48mm of material in LOS of that hit.
Right, but we’re not testing the penetrative qualities of 25mm APFSDS, this test is about the KE resistance of a block of ASPRO-HMT. Whereby you’d want to be firing in a 30 degree arc frontally, to engage all of the composite tiles found inside.
If you exceed that impact angle, you begin to miss tiles completely, reducing the total thickness of the material required to penetrate.
For this reason, STANAG 4569 is tested on individual tiles, not on specific vehicles as i’ve shown in multiple sources, and within ± 30 degrees so you are always engaging the full KE resistance of ASPRO-HMT.
Go beyond 30 in either direction and you begin missing tiles with the projectile and you are not given an accurate indication of the entire blocks KE resistance.
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If ASPRO-HMT can resist 25MM APFSDS at higher impact angles, it would actually be in favour of even higher KE resistance for the entire block, as less composite tiles are required to reach the STANAG 5 claim.
So hitting it frontally, where there is now more armor, you would see no penetration like in previous tests and even more composite tiles to go through for more KE resistance??
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