Random Stryker armour question

[rudel.dietrich]

I am trying to get a feel for what a Styrker can and cannot survive.

I will post a small list of things im curious about and hopefully get some answers.

I know many of these will be conditional but im just looking for a rough yes or no.

Direct 120mm mortar hit

Direct 85mm artillery round hit

Direct 122mm artillery round hit

152mm artillery round at 15 meters impact

85mm AT gun at 750 meters

82mm RR

107mm RR

[Holman]

None of the above?

[Battlefront.com]

We haven't done anything with this sort of stuff yet, but I think the answer is that any direct hit would knock the vehicle out comletely. The RR rounds would tear them apart in particular, I should think. However, I'd have to do more research on what the slats could do against such a round before saying so for sure. 152mm spaced apart by only 15m would probably cause a mobility kill and/or systems damage.

The Strykers simply aren't designed to handle hits from big stuff.

Steve

[Beastttt]

Direct 120mm mortar hit

Short of a heavy bunker no vehicle would survive

Direct 85mm artillery round hit

HEAT ammo maybe if it hit the slat armor APHE no

Direct 122mm artillery round hit

as above

152mm artillery round at 15 meters impact

contents yes but wheels will be trashed

85mm AT gun at 750 meters

HEAT ammo if it hits the slats

82mm RR

107mm RR

if it hits the slats

[PSY]

What is "RR"?

[RMC]

recoilless rifle

[hellfish]

RRs basically fire shaped charge rounds with a little more velocity on them compared to RPGs, right? I'd venture to think that a 73 or 82mm RR round wouldn't be very effective against the cages, right?

[John Kettler]

Beastttt,

Am presuming your analysis of 152mm HE at 15 meter standoff is for a ground burst, but the spec for the M2/M3 Bradley, for example, is against a 152mm airburst. Given your conclusion of extensive damage to Stryker mobility in the presumed ground burst case, it seems reasonable to conclude that whatever's on top of the vehicle would likely be badly torn up, if not destroyed outright. Very bad if in the mortar carrier in mid fire mission!

fytinghellfish,

There is enormous difference in MV between the RPG-7 and the 73mm SPG-9 and 82mm B-10 RRs. Isby's WEAPONS AND TACTICS OF THE SOVIET ARMY. Per page 195, the RPG-7's initial velocity is 120m/sec and peaks at 300m/sec. By contrast, page 202, the SPG-9's initial MV is 435m/sec, boosting to a screaming 700m/sec. The earlier B-10, page 202, has an MV of 320m/sec.

Regards,

John Kettler

[ October 28, 2006, 01:44 AM: Message edited by: John Kettler ]

[hoolaman]

As for the 152mm at 15m, I think we have extensive data on that as it sounds like any one of hundreds of Iraqi IED attacks.

My guess is a mobility kill but very likely crew survival.

[rudel.dietrich]

So it has very little protection against kinetic energy attacks?

And I know a Leopard 2 can survive a direct hit by a 120mm mortar.

I assume a M1A2 (HA) could as well.

[Battlefront.com]

It's a fairly lightly armored vehicle, so no... it doesn't have much mass to defend against such things like a heavy tank can. The armor is also specially designed for specific threats, especially HEAT type weapons. The designs necessary to protect against that sort of hit is generally different vs. kinetic. Kinda like body armor... good against medium type rounds, useless against high powered ones, generally useless against a bayonet.

Steve

[John Kettler]

rudel.dietrich,

The Stryker's armor is required to defeat KE weapons only through 14.5mm KPVT. Don't know the range at which it must do this, but might even be zero meters.

Hoolaman,

While I certainly agree with your argument for the countermobility case, I think it would be an entirely different kettle of fish for an overhead airburst. SOFAIK, the number of IED incidents allowing us to validate our theoretical understanding of that situation is likely to be zero, at least until the insurgents start putting IEDs atop lamp posts and telephone poles. Would imagine that a 152 round detonated parallel to the ground at that height would eat the Stryker alive, seeing as how 155mm live fire aginst M60s turned

even those heavily armored beasts into tracked pincushions. ISTR one of our Redlegs during CMBO

describing how M60 range targets were found after live fire with multiple large splinters driven right through the turret walls. Am reasonably sure that what can defeat the side of an older MBT

ought to be able to do much worse to the thin roof

armor of the Stryker, never mind anyone unfortunate enough to be exposed at the time of detonation.

Regards,

John Kettler

[Beastttt]

when I used the word contents I was refering to the personal inside the Stryker

I figure that an airbust would only have the shell casing for fragments to cause damage along with the shock wave and in general is really only useful against exposed infantry,unbuttoned vehicle crews

ground bursts will throw out a heck of a lot more fragments also the shock wave will be striking the side of the vehicle with more of a chance to strike the wheels or knock it over as opposed to pushing it down(figuring on an over head burst say no more than 30 degrees off angle

the over hang of the vehicle should shield the wheels from direct fragment strikes)

Originally posted by John Kettler:

Beastttt,

Am presuming your analysis of 152mm HE at 15 meter standoff is for a ground burst, but the spec for the M2/M3 Bradley, for example, is against a 152mm airburst. Given your conclusion of extensive damage to Stryker mobility in the presumed ground burst case, it seems reasonable to conclude that whatever's on top of the vehicle would likely be badly torn up, if not destroyed outright. Very bad if in the mortar carrier in mid fire mission!

fytinghellfish,

There is enormous difference in MV between the RPG-7 and the 73mm SPG-9 and 82mm B-10 RRs. Isby's WEAPONS AND TACTICS OF THE SOVIET ARMY. Per page 195, the RPG-7's initial velocity is 120m/sec and peaks at 300m/sec. By contrast, page 202, the SPG-9's initial MV is 435m/sec, boosting to a screaming 700m/sec. The earlier B-10, page 202, has an MV of 320m/sec.

Regards,

John Kettler

[MikeyD]

It'll be interesting to see how the Stryker Slat cage handles HEAT other than RPG rounds.

The theory behind the cage is its specially designed to exploit a peculiarity of the RPG, namely denting the body of the grenade can short-out the connection between the fuse head and the burster charge at the base. An alternate theory (of my own) is whether it shorts out the fuse or not the round would impact the bars with enough force to dent the copper HEAT cone, severely degrading formation of the piercing jet.

So how would the Slat cage handle a Blue-on-Blue AT-4 strike?

About the other big projectiles mentioned above - I do wonder how much punishment those ceramic MEXAS tiles can take. Stryker might not be able to handle two hits of anything in a row but it's shown itself to be unexpectedly robust - even earning higher points than the Bradley on a couple military websites!

[ October 30, 2006, 10:22 AM: Message edited by: MikeyD ]

[Caseck]

Originally posted by John Kettler:

rudel.dietrich,

The Stryker's armor is required to defeat KE weapons only through 14.5mm KPVT. Don't know the range at which it must do this, but might even be zero meters.

Hoolaman,

While I certainly agree with your argument for the countermobility case, I think it would be an entirely different kettle of fish for an overhead airburst. SOFAIK, the number of IED incidents allowing us to validate our theoretical understanding of that situation is likely to be zero, at least until the insurgents start putting IEDs atop lamp posts and telephone poles. Would imagine that a 152 round detonated parallel to the ground at that height would eat the Stryker alive, seeing as how 155mm live fire aginst M60s turned

even those heavily armored beasts into tracked pincushions. ISTR one of our Redlegs during CMBO

describing how M60 range targets were found after live fire with multiple large splinters driven right through the turret walls. Am reasonably sure that what can defeat the side of an older MBT

ought to be able to do much worse to the thin roof

armor of the Stryker, never mind anyone unfortunate enough to be exposed at the time of detonation.

Regards,

John Kettler

Most likely ICM-DP penetrated those M60s. (Shaped charge bomblets.) HE shell splinters don't do well against armor.

Bomblets can penetrate in excess of 4" of steel.

[John Kettler]

Caseck,

I understand what you're saying, but my recollection is that the discussion of M60 damage from 155 fire was ordinary HE PD, not DPICM.

Regards,

John Kettler

[flamingknives]

Survivability trails conducted on the Conqueror tank (WO 194/375) indicated that 31mm steel plate was sufficient to stop splinters from a fairly large shell - I forget the size and distance and can't find my notes at the moment.

19mm, on the other hand, was not sufficient to stop the splinters.

[John Kettler]

flamingknives,

Hope you find your notes. Would love to know more!

ISTR John D Salt presented the results of a wartime firing of 25 pounders in indirect fire mode against moving, crewed Churchill tanks (would guess later models). Don't recall the fire density or speed of advance, but I do recall it did little to the thickly armored tanks. He cited the PRO Report titel and number for this very exciting to the tested field experiment.

Regards,

John Kettler

[flamingknives]

Aha!

These things are always in the last place that you look.

The test was using 155mm shells airburst above the FV 214 "Conqueror" by means of a target board suspended from wires directly above the tank. The 155mm gun was laid on this directly, causing an airburst between 18 and 20 foot above the tank. It was noted that fragments from this were able to defeat the 17mm turret hatches. These were subsequently upgraded to 31mm, which provided adequate protection. It was noted that fragments from the airburst penetrated 22mm into the armour.

By contrast, .5" AP managed a maximum of 1.6" penetration from 10-15 yards

It was also observed that 25pdr fragments were sufficent to defeat the grilles on the engine deck from a distance of 50 feet, but no other part of the vehicle was affected. The engine decks were 17mm thick and, as stated, had grilles.

[dixon_el]

If you read the history of the striker there are a couple of pieces missing. When the original models came out one was taken down to a firing range and was repeatedly fired at with a 30.06. The 30.06 repeatedly penetrated the armor. The contractor then "patched" the armor to strengthen the penetrated points until the "finished" vehicle could withstand the 30.06 rounds.

Consider it fiction if you like, this took place on Steel Range on Fort Knox, Ky.

P.S. The vehicle had to be towed to the range because it wasn't operational, as usual.

[MikeyD]

"Patching" the armor for a Stryker until strong enough would simply mean swapping out thicker and thicker MEXAS armor tiles.

The Army did 'coupon testing' to the MEXAS tile package just before the first Stryker was delivered and the tests failed. They then rushed an order through for a stronger MEXAS armor package (thicker steel backing plates) to make up the difference. Unfortunately the supplier goofed! They seem to have read the wrong numbers on the form and accidentally supplied a whole Brigade's worth of - I think - 14.5mm steel backing plates for the tiles (the plates were meant to defeat 14.5mm mg fire). I believe it wasn't until the first Stryker Brigade was on its way to Iraq that the error was noticed and the supplier had to rush extra sets of 5mm backing plates to the field to bring Stryker up to the mandated 56mm equivalent armor. Oh, and on top of that Slat Strykers also have that standoff layer of (soft?) steel on the hull side to soak up even more energy from the bombs.

What's the armor equivalent to a MEXAS-tiled Bradley? Something like 100mm, or the bow of a T55? I think Bradley's MEXAS tiles use a stronger (and more expensive) type of ceramic. And MUCH thicker backing plates!

[ November 15, 2006, 10:03 AM: Message edited by: MikeyD ]

[daniel#2]

As an aside: killing a Stryker by RPG fire seems to require two hits. Whether this is to do with an increased chance of hitting something vital, or fires on multiple aspects that cannot be suppressed compared to a single, localized one. Slat armor seems to work no greater than 50% of the time when hit with anti-armor (HEAT) rounds; 73MM PG-7M, 85MM PG-7G and 73MM NADER being the three most likely to have been used by Iraqi rebels.

Sources are the official AAR of Stryker units and observations on Stryker losses.

[MikeyD]

Huh! That's a much poorer showing for Stryker than I had heard.

I had heard (entirely 3rd hand and a couple years ago, I admit) that Slat armor was working about 50% of the time - by 'work' they meant shorting-out the nose fuse and no detonation. Of the RPG rounds that detonated against the cage, the combination of being bashed against the bars and the ceramic MEXAS tiles & stand-off side armor was doing a good job of degrading the HEAT jet. Slat's much touted success per-round-fired (including an admittedly high percentage of duds & misses) looked to be quite impressive.

Has Slat's statistical success rate been dropping over time? As the war progressed I've noticed the Army's 'good news' reports on the vehicle has been getting more and more equivocal - "Never lost a man riding in a Stryker... while buttoned... from an RPG... on a Tuesday." Lately it seems they've given up on good news and gone to no news entirely.

[rune]

I'd like to see some of the reports. All I have found is a total loss of 23 Strykers due to all causes, including rollovers. I even went to the GAo and couldn't find any figures. Where did you find the losses at, I would love to look at the figures.

Rune