RPG stuck in Stryker's slate armour

[Double Tap]

http://img236.imageshack.us/img236/4043/mosul2c2020iraq202004201105vr.th.jpg (http://img236.imageshack.us/my.php?image=mosul2c2020iraq202004201105vr.jpg)

[LordHalbert]

That looks dangerous.

[seruriermarshal]

Strykers are really great , soldiers are safer because them .

:D

[muede]

Funny, this time the thing worked, but still its a mixed blessing as the military knows, cause should it hit the bars and detonate the aparatus will _increase_ the effectiveness of the weapon giving it the opitimal stand off detonation distance. :|

[Name Taken]

Funny, this time the thing worked, but still its a mixed blessing as the military knows, cause should it hit the bars and detonate the aparatus will _increase_ the effectiveness of the weapon giving it the opitimal stand off detonation distance. :|

REALLY?

[He219]

Increase to 'optimal standoff distance'; How so?

Talk Physics to me, muede!
:D

[Michael RVR]

Funny, this time the thing worked, but still its a mixed blessing as the military knows, cause should it hit the bars and detonate the aparatus will _increase_ the effectiveness of the weapon giving it the opitimal stand off detonation distance. :|

Care to explain why a HEAT warhead would even want standoff distance ?

[Bombtrack]

I like the guy on the left's patches

[WoodChipper]

Nice Photo. Good to see those cages work. The slope in the front may have deflected it. Anyway I bet the Driver was relieved it was there.

[XS203598]

Bursting devices have been around for decades. If you want me to do the math for you, I will; or you could Google B-40, RPG or Monroe Effect. You will never look at a wine bottle the same again.

[PhillyMobster]

Hmm. Are those normal DCUs? The pockets on the sleeves and all...

[HUAH]

That looks dangerous.I would hope they defused it first!

[Pook2]

No those are the prototype ACU's in the DCU pattern.

[Kingswat]

Cool pic, glad to see the stuff is working.

[muede]

Increase to 'optimal standoff distance'; How so?

Talk Physics to me, muede!
:D
As the blast jet forms big off from the armor and not in contact with it, it has better performance, specially with the PG-7s which have kinda slow fuze.. basic stuff.

[joshfox0]

i dont think thats dangerous :s it looks like its already lost its warhead to me but the back of it is left stuck in the cattlegrid.

[SimpleSimon]

Increase to 'optimal standoff distance'; How so?

Talk Physics to me, muede!
:D
As the blast jet forms big off from the armor and not in contact with it, it has better performance, specially with the PG-7s which have kinda slow fuze.. basic stuff.

I don't believe that statement is accurate. The reason an RPG is effective is because it creates a shape charge upon contact (shape charge munition). The bird cage causes it to detonate away from the hull which mitigates the shape charge effect.

[UoUo]

does RPG even have war head? i mean does it have exsplosive?

[muede]

does RPG even have war head? i mean does it have exsplosive?
Yes, it has a warhead, which in turn form this special metal cone its carrying (usually copper alloy) to a high temp / high velocity jet that will try to puncture the armor..

[Resevoir Hogs]

I believe the idea is that the only part of the RPG capable of penetrating Stryker or Abrams armour is the molton center. There was a thread a while back about an M1 having a 22 sized hole shot through its turret from a new RPG round. The cage prevents the center shaped charged thingy from penetrating. (see how much of a munitions expert I am lol)

[muede]

The purpose of the gage its to get the projectile trapped like shown in the photo or optionally just to break the nose of the projectile which contains the triggering mechanism so it wont detonate at all.. but if it detonates and the jet is directed at the vehicle its pretty much done for.

[crinkler]

Increase to 'optimal standoff distance'; How so?

Talk Physics to me, muede!
:D
As the blast jet forms big off from the armor and not in contact with it, it has better performance, specially with the PG-7s which have kinda slow fuze.. basic stuff.

WTF are you talking about? That goes against what rpgs are designed to do, ever heard of a shape charge? Um it works when used properly. It doesn't work better at a distance.But if you know something 1,000's of people don't you should tell them youll make billions. :backhand:

[crinkler]

The purpose of the gage its to get the projectile trapped like shown in the photo or optionally just to break the nose of the projectile which contains the triggering mechanism so it wont detonate at all.. but if it detonates and the jet is directed at the vehicle its pretty much done for.
Never knew that, so how do you break off the nose? HAHAHA with out it exploding. rofl

[szr]

muede, for someone who likes to portray someone who knows what they're talking about, you sure do a crappy job. I would have thought you would have become gunshy and timid after getting repudiated repeatedly in other threads, but I guess stupidity knows no fear. Give it a rest, bud.

[priccobe]

pix isn't showing up, anyone have it in another location?

[Double Tap]

pix isn't showing up, anyone have it in another location?
fixed

[muede]

The purpose of the gage its to get the projectile trapped like shown in the photo or optionally just to break the nose of the projectile which contains the triggering mechanism so it wont detonate at all.. but if it detonates and the jet is directed at the vehicle its pretty much done for.
Never knew that, so how do you break off the nose? HAHAHA with out it exploding. rofl
Stranger things has happened.

http://img301.imageshack.us/img301/5219/asasasa1mf.jpg (http://imageshack.us)
IE, not in the red area but on base of it when it shall brake off and malfunction. ;)


muede, for someone who likes to portray someone who knows what they're talking about, you sure do a crappy job. I would have thought you would have become gunshy and timid after getting repudiated repeatedly in other threads, but I guess stupidity knows no fear. Give it a rest, bud.
Sure pal, why dont you try serving for a while? Youl learn miracles how the stuff works. I would love to have you in my troop, lots of drill practice involving even more falling back would be involved. But for smart ass like you i suggest google and trying to find action and basics reports of the concept if you dont take my word for it, also it might be that i cannot explain the procedure 100% accurately how it works in english as that is not my 1st language belive it or not, but i do know how it works and why.

Regards.

[Bomb kicker]

Look Gents,
Let me school the uninformed about anti armor munitions.

Any munition with a warhead incorporating a shaped charge (which 'YES' does contain an explosive main charge for the individual who asked) requires a calculated standoff. If you look at anti armor munitions ranging from WWII US 90mm HEAT projos, to modern day 120mm US tank rounds you will see this standoff (either a "spike" or forward end of a cone) in the front of it


In the case of the PG-7 variants produced all over the world, you will see that they incorporate a point initiating base detonating fuze. What this means is the aluminum tip covers the piezoelectric element. The cone is 2 pieces...the forward is hollow (thus allowing the optimal standoff for the copper linner to properly from a molten 'JET' which gives the armor penetration), the rear is where the inverted cone and the main charge is located. Behind that is the base detonating fuze then the venturis, propellant and stabilizing fins.

ALL anti armor rounds utilizing a shaped charge REQUIRE a proper standoff in length and material to be effective.

[crinkler]

Look Gents,
Let me school the uninformed about anti armor munitions.

Any munition with a warhead incorporating a shaped charge (which 'YES' does contain an explosive main charge for the individual who asked) requires a calculated standoff. If you look at anti armor munitions ranging from WWII US 90mm HEAT projos, to modern day 120mm US tank rounds you will see this standoff (either a "spike" or forward end of a cone) in the front of it


In the case of the PG-7 variants produced all over the world, you will see that they incorporate a point initiating base detonating fuze. What this means is the aluminum tip covers the piezoelectric element. The cone is 2 pieces...the forward is hollow (thus allowing the optimal standoff for the copper linner to properly from a molten 'JET' which gives the armor penetration), the rear is where the inverted cone and the main charge is located. Behind that is the base detonating fuze then the venturis, propellant and stabilizing fins.

ALL anti armor rounds utilizing a shaped charge REQUIRE a proper standoff in length and material to be effective.
Yes, that just common sense, but they are already at proper standoff when they make contact with their target, they arent as effective the further off they are. So the idea that going off from further away will do more damage simply isnt true. They are designed to be as effective as possible.

[Son_Of_Suvorov]

Look Gents,
Let me school the uninformed about anti armor munitions.

Any munition with a warhead incorporating a shaped charge (which 'YES' does contain an explosive main charge for the individual who asked) requires a calculated standoff. If you look at anti armor munitions ranging from WWII US 90mm HEAT projos, to modern day 120mm US tank rounds you will see this standoff (either a "spike" or forward end of a cone) in the front of it


In the case of the PG-7 variants produced all over the world, you will see that they incorporate a point initiating base detonating fuze. What this means is the aluminum tip covers the piezoelectric element. The cone is 2 pieces...the forward is hollow (thus allowing the optimal standoff for the copper linner to properly from a molten 'JET' which gives the armor penetration), the rear is where the inverted cone and the main charge is located. Behind that is the base detonating fuze then the venturis, propellant and stabilizing fins.

ALL anti armor rounds utilizing a shaped charge REQUIRE a proper standoff in length and material to be effective.

Very informative post. I have read somewhere though, that the length of the hollow cone in the older RPG-7 rounds is actually not the optimal stand-off distance for the type of warhead used (apparently a few more inches gives better penetration). What is interesting about RPG-7 rounds is that the piezoelectric crystal uses the round's body and the copper cone as positive and negative "wires," so some types of slat armor have a proper spacing that will crush the copper cone and body together and short-circuit the crystal, or at least that's what some people theorize happened to dud rounds stuck in slat armor (I've read this happened occassionaly in Vietnam where they would use rolled-up chain-link fence as improvised slat armor). The type of slat armor used on the Stryker works by sometimes causing the copper jet to fizzle out due to the greater standoff distance, like shown on this page (http://www.niistali.ru/science/secure_en.htm). According to the data on that web page and the statistics from Iraq, the Stryker's slat armor may also not be as optimally designed as it could be (http://www.militaryphotos.net/forums/viewtopic.php?t=43160&highlight=steel+slat).

[melon]

edit

[GazB]

The bird cage causes it to detonate away from the hull which mitigates the shape charge effect.

Nope, the cage duds the round by crushing the sides of the warhead nose and shorting out the Peizio electric fuse in the nose. It generally works 50-60% of the time. The 40-50% of the time that the round detonates it will generally penetrate the vehicle as the vehicle that have such grill armour are either light weight vehicles (in this case) or on heavy vehicles like tanks this grill armour is used over areas not well protected by real armour like the engine or hull sides.


does RPG even have war head? i mean does it have exsplosive?

It would do little damage if it had no explosive. Its velocity alone is not enough to penetrate armour.


It doesn't work better at a distance.But if you know something 1,000's of people don't you should tell them youll make billions.

Look at the design of a modern HEAT warhead. Particularly an effective weapon like the European Milan missile. They have very long nose probes that allow the warhead to detonate well back from the target to allow their HEATs to work effectively.
The current Russian 125mm Tank fired HEAT warhead has 3 HEAT warheads that fire one after the other... first a small warhead to blow off any ERA and then a centre and a rear mounted warhead to increase penetration.


Never knew that, so how do you break off the nose? HAHAHA with out it exploding.

You could do that quite easily. Unless the tip of the nose is crushed to fire the detonator the warhead will not explode.

If you look at the picture of the RPG rocket muede posted the tip contains the fuse (this is a later round with a more complex fuse that won't be shorted out like the really old RPGs the Iraqis use) but the HEAT charge is not in the front of the warhead. If you cut the warhead in half and opened it the pointed front contains no explosive at all, only the rear of the warhead area contains the warhead, the front is "standoff" space for the jet to form.
Where the rocket narrows down to 40mm calibre that is the rocket engine. The triangular bits that stick out below the warhead but above where it narrows right down to 40mm is where the rocket exhaust blasts out when the rocket is in flight. The green painted stuff at the bottom of the rocket is solid rocket fuel that detonates inside the launcher to blow the rocket out and send it down range toward the target. Underneath the solid fuel are stabilising fins that fold out. After the rocket has travelled 12 or so metres the sustainer rocket lights up with the exhaust coming out the triangle bits. The extra velocity from the sustainer rocket the RPG-7 has a flat trajectory and short flight time, which makes it more accurate and much more effective than older panzerfaust type weapons.


Yes, that just common sense, but they are already at proper standoff when they make contact with their target, they arent as effective the further off they are.

The early PG-7 rounds needed greater standoff range than their design allowed. Reduction in penetration was accepted due to the penalties of altering the design. Considering the Stryker will not have 280mm or armour plate I think a 30% reduction in penetration performance would make no difference at all to the crew even with the most ancient PG-7 HEAT model.

[dacanadianbomb]

Wow, that post tops my list of interesting posts this week.Very nice description, I even udnerstood what you were talking about.

Not knowing anything about the rockets, I still would feel uncomfortable handling a stuck rocket with aguy next to me with a hammer :-),

So if the slated armour isnt as effective, and the nose beign crushed is a pre-requisite for detonation, what about panels with a high degree slant ?
Woudl this then act as a deflect or is the round travelling so fast that it would crush the nose anyway regardless of angle it hit at ?
Just throwing that out there, eventhough my uninformed guess is the latter is prolly more realistic.

[Resevoir Hogs]

Have there even been any casualties from attacks on Strykers yet? I mean I know some have been destroyed but it was my impression the entire crew made it out unharmed.

[MARINO]

Wow nice, Spanish BMR's survived to RPG attacks too. woot

[RecceGuy]

Wow, that post tops my list of interesting posts this week.Very nice description, I even udnerstood what you were talking about.

Not knowing anything about the rockets, I still would feel uncomfortable handling a stuck rocket with aguy next to me with a hammer :-),

So if the slated armour isnt as effective, and the nose beign crushed is a pre-requisite for detonation, what about panels with a high degree slant ?
Woudl this then act as a deflect or is the round travelling so fast that it would crush the nose anyway regardless of angle it hit at ?
Just throwing that out there, eventhough my uninformed guess is the latter is prolly more realistic.

In answer to the last portion of your post we had an unarmoured Land Rover hit on the passenger door by an RPG in Basra. Due to the angle that the round hit the door the det in the nose wasn't initiated and the round skipped off. It hit the floor about 2 metres behind the Rover and though the blast shredded the Rover rear end the crew escaped with concusion and bleeding from the ears. They managed to drive the Rover out of the killing area and escape. The Rover Commander still suffers hearing problems now. So I guess that the det has to hit at a fairly steep angle to initiate the warhead.

[He219]

Thanks for your informative replies Bomb kicker, Son_Of_Suvorov & GazB!

If I am interpreting your information correctly, the nose cone serves not only as an aerodynamic element ahead of the Shaped Charge, but is preceeded by a piezoelectric trigger mechanism and incorporates a copper liner to focus the expanding Plasma Jet (created by detonation of the shaped charge) through a small cross secitonal area at the tip of the cone for optimal armor penetration.

Does the copper cone actually serve as a conduit to develop and focus an armor piercing Plasma Jet, or is it consumed and merely serves to establish a pre-set standoff distance for the shaped charge?

It the copper cone serves as a focusing conduit and if the missile is detonated at a distance away from the armor surface that exceeds the length of the cone intself, wouldn't the focus of the plasma jet start to Diverge respective to the shape of the cone?

ie: if the distance that the RPG is detonated away from the armor surface exceeds the length of the Shaped Charge and inherent Focusing Cone, wouldn't the effect of the Plasma Jet be geometrically mitigated over an ever increasing distance?

Hope I didn't loose anybody!
:D

[RecceGuy]

Basically if the round is detonated too far from the armour the jet is not the thin penetrating 'slug' that it should be. It becomes wider and slower and therefore has a tendency to splash onto the armour instead of penetrating as it should. I know splash might not be the correct word but that isin effect what happens.

[Son_Of_Suvorov]

I had a really good diagram of a round somewhere, but I can't find it now. This vandalized cross-section should be good enough for our purposes:

http://www.users.on.net/~grypen/Downloads/RPG-7_OG-7V_to_scale.jpg


If I am interpreting your information correctly, the nose cone serves not only as an aerodynamic element ahead of the Shaped Charge, but is preceeded by a piezoelectric trigger mechanism and incorporates a copper liner to focus the expanding Plasma Jet (created by detonation of the shaped charge) through a small cross secitonal area at the tip of the cone for optimal armor penetration.

Does the copper cone actually serve as a conduit to develop and focus an armor piercing Plasma Jet, or is it consumed and merely serves to establish a pre-set standoff distance for the shaped charge?

In the above diagram (the numbers are kind of hard to make out), 14, at the tip of the round, is the fuse, a piezoelectric crystal that emits an electric current when put under mechanical stress ie crushed. 18 is the outer body cone of the round, and 17 is the copper liner in question, and together with parts 19, 35, and 20 they make up the positive and negative "wires" to connect the fuse to the detonator at the base of the round (everything right of part 22 is part of the rocket - when the yellow fuel in the left section of the rocket burns up, it causes the round to explode, which is the mechanism behind the additional timed "fuse" that causes the round to explode after 5 seconds of flight). From what I have read, the copper liner 17 only provides additional material for the shaped-charged jet. Only the copper cone 19 is necessary to make and focus the jet per the Munroe effect (http://en.wikipedia.org/wiki/Munroe_effect), and many (most?) other shaped-charge warheads (including the original Panzerfaust) only have the one inner cone.


It the copper cone serves as a focusing conduit and if the missile is detonated at a distance away from the armor surface that exceeds the length of the cone intself, wouldn't the focus of the plasma jet start to Diverge respective to the shape of the cone?

ie: if the distance that the RPG is detonated away from the armor surface exceeds the length of the Shaped Charge and inherent Focusing Cone, wouldn't the effect of the Plasma Jet be geometrically mitigated over an ever increasing distance?

The optimal stand-off distance at which the jet has enough time to form but doesn't yet start to fizzle out is determined by the size and shape of the inner cone (19 in the above diagram). I don't know what the relationships are.



Interesting fact: the small round pictures in the lower-right corner is not in fact an OG-7V (fragmentation round) but a training round. This seems to have confused quite a few Iraqi insurgents as well, as there are several photographs of them running around with those training rounds loaded in their RPG-7s (here's an example (http://en.wikipedia.org/wiki/Image:Iraq_RPG1.jpg) of a particularly clueless man who doesn't even know how to hold the weapon).

[Warrior(Spain)]

AWESOME!!

[He219]

It the copper cone serves as a focusing conduit and if the missile is detonated at a distance away from the armor surface that exceeds the length of the cone intself, wouldn't the focus of the plasma jet start to Diverge respective to the shape of the cone?

ie: if the distance that the RPG is detonated away from the armor surface exceeds the length of the Shaped Charge and inherent Focusing Cone, wouldn't the effect of the Plasma Jet be geometrically mitigated over an ever increasing distance?

The optimal stand-off distance at which the jet has enough time to form but doesn't yet start to fizzle out is determined by the size and shape of the inner cone (19 in the above diagram).
Exactly my point. I used the term Focus as an analogy to Focal Length to best describe optimization.

The Copper Cone acts as a 'nozzle' to induce a plasma jet, optimized by the relationship of the shaped charge size and the geomety of the Focusing Cone itself ...

http://www.vidisco.com/images/thumb/1---color-RPG_Missile.jpg
Hi-Res (http://www.vidisco.com/images/full/1---color-RPG_Missile.jpg)

http://www.visionengineer.com/aero/rocket1.gif

... the plasma stream diverging immediately after passing through the 'nozzle' throat of the Copper Cone, it's energy weakening geometrically @ ATP (atmosp temp & pres) as it relates to an ever increasing distace toward the target surface.



Therefore I would be forced to conclude that the Plasma Jet becomes less effective in penetrating characteristics the greater the distance from the nozzle throat to the target surface, ie Standoff Distance.
p-)


Good Reading:
http://www.shrapnelcommunity.com/threads/showflat.php?Cat=&Board=spmbttoe&Number=364417&page=0&view=collapsed&sb=5&o=&fpart=2
and
http://www.d-n-i.net/fcs/iraq_and_the_RPG-7.htm

[FozzieBear]

so... muede got owned AGAIN!!! :lol:

[CH4RL13]

Look you guys are funny. Just google it. The slate armor is designed to detonate the warhead away from the vehicle. Simple as that.

Just go here and read everything you want to:

http://www.google.com/search?hl=en&lr=&q=stryker+slat+armor

31C

[He219]

Slat Armor is most effective against older PG-7 and PG-7V type warheads because it can either catch or crush the projectile without detonation.

If any HEAT charge is detonated by scoring a direct hit on the Slat itself, the Plasma Stream retains it's designed effect on the Strike Surface, less the atmospheric effects over the Standoff Distance.

The key is that Stand-Off distance doesn't increase the penetrating effect of a HEAT charge.

In modern HEAT charges, standoff distances become neglegable.

[Marsh]

Look you guys are funny. Just google it. The slate armor is designed to detonate the warhead away from the vehicle. Simple as that.

Just go here and read everything you want to:

http://www.google.com/search?hl=en&lr=&q=stryker+slat+armor

31C

Erm,
Funny are we? Actually your suggested sources strongly support the thesis that that the "Internet is the University of Fools".

I am not suggesting you are a fool, but it might be wiser to read more (I would suggest you have a look at the August edition of Janes International Defence Review and look at the article by Richard Ogorkiewicz, in order to understand the function of slat or grille armour), or get real world experience before you make statements such as you have done.
Slat armour is designed to crush and short circuit the fuse of early model RPGs, preventing their detonation. If the slat armour detonates the RPG it has failed. A distance of 1 meter is required to degrade the molten jet formed by a HEAT warhead, (it is not "plasma" by the way) and prevent it from penetrating the base armour of say, a Stryker APC. However, the slat armour of the Strykeris around 200-250mm from the base armour. Although the conical kill zone once the jet penetrates the base armour will be reduced, it is still sufficient for a catastrophic kill.

cheers

Marsh

[Kaplanr]

My understanding was that a shaped charge of the type used on man-portable launchers (and this is from the 80s) like the LAW or RPG-7 needed to have almost direct contact with the surface it needed to "jet" into. One of the lessons of the Yom Kippur war was that enough infantry with shoulder launched weapons could decimate enemy armour, especially armour w/out infantry cover.

The technological results were the ERA applied to tanks and seen in the Mid-East on Israeli M-60s and Centurions in Lebanon, and in the TOGA armor used on Zeldot (M-113 APCs). The TOGA is certainly not reactive, but forces the charge to expend itself before fully penetrating the vehicle's skin. I will say that my 2 day's training as an RPGist in the IDF while short on theory (if you couldn't tell) was long on vehicle profiling and establishing the best angle of attack. The culmination was live fire on a derelict M-113 (w/out TOGA) and I can only say I swore to never be a driver of one of the things.

[Marsh]

My understanding was that a shaped charge of the type used on man-portable launchers (and this is from the 80s) like the LAW or RPG-7 needed to have almost direct contact with the surface it needed to "jet" into. One of the lessons of the Yom Kippur war was that enough infantry with shoulder launched weapons could decimate enemy armour, especially armour w/out infantry cover.

The technilogical results were the ERA applied to tanks and sen in the Mid-East on Israeli M-60s in Lebanon, and in the TOGA armor used on Zeldot (M-113 APCs). The TOGA is certainly not reactive, but forces the charge to expend itself before ully penetrating the vehicle's skin. I will say that my 2 day's training as an RPGist in the IDF while short on theory (if you couldn't tell) was long on vehicle profiling and establishing the best angle of attack. The culmination was live fire on a derelict M-113 (w/out TOGA) and can only say I swore to never be a driver of one of the things.

Hi Kaplanr, :)
As you probably know, Toga was designed to protect against 14.7mm AP rounds, being designed to fragment and tumble them, thus protecting the base armour of the APC. It is true that Toga does have some protective qualities against RPG rounds. However, at best, it reduces the conical kill zone of the RPG warhead, once it penetrates the baseline armour, from around 110 degrees to 30 degrees around the axis of entry. Like you, I would not want to be in that M113....
Cheers

Marsh

[XS203598]

So I guess my analogy about the wine bottle generated little interest. A very expensive champaigne bottle (with a deep cone) and the appropriate amount of C-4, would drill a quarter sized hole through a differential (rear end). This is one of the reasons you should pay attention in math class.

[NicNZ]

I actually dont understand how a PG's narrow molten stream, when projected into the interior of a vehicle, can completely defeat the target vehicle, particularly when ammunition is stored separately. Can someone explore this a bit?

[Seraphim]

I actually dont understand how a PG's narrow molten stream, when projected into the interior of a vehicle, can completely defeat the target vehicle, particularly when ammunition is stored separately. Can someone explore this a bit?

Extreme heat and having that damn thing bouncing around in a confined space.

[American Patriot]

Extreme heat and pressure

[Sinfulcurves_AK107]

I don't feel like reading through all of this, barely skimming through various messages, but anyways... I wouldn't be surprised if a Stryker can be penetrated -- with the right warheads and tactics... Take for example the RPG-29 (using the PG-79V round, 105mm) or the PG-7VR WH's, are a mixture of HEAT/HEDP

[He219]

Nobody is saying slat armor makes armord vehicles impervious, yet their use is validated by the sheer abundance of older PG-7 warheads than the exotic ones you just described ...


Extreme heat and pressure
Indeed.

If it is not a 'plasma jet' then what does the 'molten stream' consist of?

[Seraphim]

Well heat in a confined space = pressure....like a pressure cooker.

[He219]

Hehe,

The SC is an explosive compound formed around a metal (usually copper) cone, with the base of the cone oriented on the target. When the SC detonates, the energy wave created travels through the explosive until it reaches the angled walls of the cone. Once there, the wave's energy vector is redirected to a point just in front of the base of the cone, focusing all of the SC's energy upon a single point, thus reducing the copper cone into a superplastic state and superheated gas, called plasma. This metal plasma jet, traveling at the propagation speed of the explosive used to form the plasma (thousands of meters per second) would then strike the target, burning its way through the metal and spraying the interior of the vehicle with superheated gases and molten metal. Source (http://www.military.com/soldiertech/0,14632,Soldiertech_EFP,,00.html)

;)

[sferrin]

Go here. (Not dialup friendly)

http://pegasus.me.jhu.edu/~molinari/Projects/Shape/SLIDE-1.html

[sferrin]

I actually dont understand how a PG's narrow molten stream, when projected into the interior of a vehicle, can completely defeat the target vehicle, particularly when ammunition is stored separately. Can someone explore this a bit?

Sometimes it doesn't. For example the "mystery round" that punched through the side of an M-1 and one of the seats inside. It was a golden BB if for no other reason it did so little when it got through that it was probably not all that big of a warhead to begin with.

[Sinfulcurves_AK107]

I actually dont understand how a PG's narrow molten stream, when projected into the interior of a vehicle, can completely defeat the target vehicle, particularly when ammunition is stored separately. Can someone explore this a bit?

Sometimes it doesn't. For example the "mystery round" that punched through the side of an M-1 and one of the seats inside. It was a golden BB if for no other reason it did so little when it got through that it was probably not all that big of a warhead to begin with.

They speculated that it was an RPG-22. The RPG-22 is basically the Russian's version of the LAW. Yep, the caliber is kinda small (70mm)

[He219]

http://www.geocities.com/Augusta/8172/figb.jpghttp://www.geocities.com/Augusta/8172/figc.jpg

When a shaped charge (see pic. A) detonates the energy is concentrated to the center of the hollow space in front of and along the axis of the charge (see simplified in pic.B). This phenomen, called the Monro - effect, is still not completely understood in every detail. A forceful jetstream of the explosion gases results that hits the steel target with a speed of typically 8000 meters per second (26,000 fps) and penetrating pressure in excess of 10 million kg/cm2 (3.4 mio. pounds per square inch; other sources: 1.2 million kg/cm2 = 0.44 mio. pounds per square inch) (see pic.C). The effect can be increased by putting a metal "liner" to the surface of the hollow. When the explosion occurs, the liner metal is formed into a spike of molten metal (although there is some discussion on whether it is liquid or solid; most times it is referred to a "plasma" jet, plasma not in the technical subatomic sense but in the sense of an in-between state of the metal between liquiduous and solid). To be most effective, the shaped charge has to be detonated at the right distance from the target. If it detonates too close to the armor, the plasma-jet hasn't formed out before hitting the surface and the effect is lessened somwewhat. If detonated too far from the armor surface, the plasma jet has unfocused and partly spent itself already (this effect is used in applying spaced armor, described below).
Source (http://www.geocities.com/Augusta/8172/panzerfaust1.htm)
;)

[SimpleSimon]

Increase to 'optimal standoff distance'; How so?

Talk Physics to me, muede!
:D
As the blast jet forms big off from the armor and not in contact with it, it has better performance, specially with the PG-7s which have kinda slow fuze.. basic stuff.

I don't believe that statement is accurate. The reason an RPG is effective is because it creates a shape charge upon contact (shape charge munition). The bird cage causes it to detonate away from the hull which mitigates the shape charge effect.

So my original statement was correct....but far less technical than some of the information here. Great thread. (substitute conical blast, plasma, standoff distance, slat armor, or any other buzzword where appropriate)

:hug:

[NicNZ]

Sometimes it doesn't. For example the "mystery round" that punched through the side of an M-1 and one of the seats inside.

That is exactly the event that I had in mind when I asked the question. Im still not entirely convinced that heat and over pressure are the causes of damage. Wouldnt modern crew protection systems prevent the heat from reaching fatal levels, and would there really be fatal pressure? In either case it doesnt seem like the plasma stream would cause a great deal of physical damage unless it was a "lucky shot".

[Jippo]

I actually dont understand how a PG's narrow molten stream, when projected into the interior of a vehicle, can completely defeat the target vehicle, particularly when ammunition is stored separately. Can someone explore this a bit?


It doesn't have that big effect on thin-armored vehicles as tanks. In MBT's the armor in the way of the jet is melted and becomes part of the jet so inside the acting force is bigger. But even in that case penetration of HEAT jet doesn't by all means destroy the tank. It will harm and destroy crew, machinery, fuel, ammunition in it's way, but it's destructive power is not very big. It requires secondary effects like ammunition cook-off, fire etc.. to disable the tank.

APC's have very thin walls, less ammunition and lots of empty space (compared to MBT), and thus it is not uncommon for a APC to survive multiple RPG hits.


-jippo

[Turhapuro]

There should be plenty of data of RPG hits against M113 APC in Vietnam. So what was their main conclusion about penetrating hit? Casualties etc? I found some articles from Google, but they look more like newspaper articles so I don't think they are credible.

[Shadow]

http://mitglied.lycos.de/jplabxt1/stand.jpg

W/O Stand-Off:
http://mitglied.lycos.de/jplabxt1/wostand.jpg

With Stand-Off:
http://mitglied.lycos.de/jplabxt1/wstand.jpg[/img]

[Jippo]

http://mitglied.lycos.de/jplabxt1/stand.jpg

W/O Stand-Off:
http://mitglied.lycos.de/jplabxt1/wostand.jpg

With Stand-Off:
http://mitglied.lycos.de/jplabxt1/wstand.jpg[/img]


And with too much stand-off, there will not be even a dent. There is a "convergence" range for all types of HEAT and the slat armor forces explosion before round is in correct distance. So out of "focus" so to speak.


-jippo

[Bomb kicker]

Shadow, good example pics. For those out there who train with demo this is one of the common tasks taught...the value of a good standoff.

The comment regarding the wine bottle bottom is another excellent example. We've (EOD) tested out different venting/low order procedures using wine bottles packed with C and using Mk 80-series bombs on ranges in the states and smaller targets here on Oki.

As long as you have the inverted cone or even a piece of angle iron (either with a liner or just a notch cut into a block of C) along with a standoff you will have some sort of penetration. As long as your target is able to be penetrated by your corrisponding charge of course.

[Shadow]

And with too much stand-off, there will not be even a dent

Right that's pretty obvious. In the last two pictures the shaped charge had a stand-off of 3cm.

[Kaplanr]

I actually dont understand how a PG's narrow molten stream, when projected into the interior of a vehicle, can completely defeat the target vehicle, particularly when ammunition is stored separately. Can someone explore this a bit?

Chicken and egg. Many of the storage and crew improvements in "modern" armor are a result of battle assessments from the 70s and 80s. Was just reading Hammel's "Duel for the Golan" (mediocre at best), and he talks about Israeli loaders keeping 2nd and 3rd shots at hand, under seats and otherwise unprotected. I'm sure that's not the case today.

There's also the unfortunate truth that what works on one weapon won't against another. RPG7s are relatively good because they're light, no-tech, cheap and effective especialy against soft targets. With a little bit of forethaught they're also easy to overcome - either uparmor or better infantry support and suppression. Again, going back to the Yom Kippur War, it required that much more effort to suppress the Sagger fire, especially in the more open areas of Sinai.

What I don't know, is if the Sagger works on the dame principle as the RPG.

[muede]

Sagger is a guided anti-tank missile with far greater effective range about 10 times more, but the warhead is similar to the RPG-7s, in concept that is as are by default warheads of all AT rockets and missiles that is their of shaped charge / HEAT type with all its variations including different kinds of explosives, fuzes and attack methods (dive / top attack / direct) and of course dual HEAT which trys to bypass reactive armor.. with few exceptions being HEDP that rely on kind of plastic explosive to do the damage.. and then theres that at least one new missile being deveploped for US Army that relys on kinetic energy in doing the damage having velocity similar or even greater than that of sabot fired out of anti-tank gun of MBT and uses tungsten / DU core to to the penetration. And still almost forgot the FAE types, which at least Russians use and i think hellfire and SMAW also have variants which under certain conditions can be very lethal to crews and equipment.

[muede]

And of the RPG-7 maybe our knowing Russian friend could shed some light in the matter of the optinal detonation distance as ive understand the round as intact is designed to give this, but that at least on the early (earlier) variants the trigger mechanism was somewhat too slow and and the projectiles tented to deform somewhat when hitting the target before having the time to detonate and lose this optimization due it, on highest possible impact speeds which is about 300-330m/s.

[Herrmannek]

everybody forgets that rpg optimal stand-of-point or whatever you call it is designed to happen when piezolectric detonator meets the armor, anything closer of further will do less damage, esspecialy if projectile will bend on the cage or not explode at all(half of the times)... Cage armor in no case will improve penetration of the rpg...

[GazB]

So if the slated armour isnt as effective, and the nose beign crushed is a pre-requisite for detonation, what about panels with a high degree slant ?
Woudl this then act as a deflect or is the round travelling so fast that it would crush the nose anyway regardless of angle it hit at ?


But what angle do you choose? Angle in this case is only effective if it prevents the fuse from firing the warhead. A high angle from a frontal launch might not be a high angle from the side or rear, or from above. Also remember the trajectory of the RPG-7 is not completely flat so it may impact on a slightly downward, level or even upward angle.


Hope I didn't loose anybody!

Sorry, you did.

Basically to make a shaped charge warhead you need one block of HE, one wine bottle and a sheet of copper that can be shaped. Take the wine bottle a plunge it into the block of HE with the cork end first. This will create a sort of cone shaped depression in the HE. In that depression you put a layer of copper. When you detonate that HE the outer area of the HE will blow outwards but in the depression created by the wine bottle the explosive will blow inwards and eventually focus on a point or strip. (if you visualise poking a rod down the neck of the wine bottle that is basically where the copper will end up, heated and travelling at very high speed. The explosion will also push this rod of very hot material forward and it will travel forward like a beam of very very hot and very fast material. The copper is not there for its electric properties, it is there to add mass and substance to what would otherwise be just some very hot gas. The copper liner moves inwards to form a rod and forward at the sme time and depending upon the shape of the depression in the HE it will need a few cms or even a few metres to form properly. The BILL ATGM for example flys over its target and fires its HEAT warhead over a metre above the tanks roof so it will be designed to penetrate armour from a great standoff distance. A belly mine that has a rod sticking up that fires the mine when a tank drives over top and touches the rod will also be a distance from the armour it is to penetrate. The Soviets and British and Americans had mines that sit by the road side that have large plate shaped HEAT warheads that will penetrate 400mm of armour from 50m away. It depends upong the design.


Therefore I would be forced to conclude that the Plasma Jet becomes less effective in penetrating characteristics the greater the distance from the nozzle throat to the target surface, ie Standoff Distance.


It depends upon the distance the HEAT warhead needs to properly focus its penetration stream. As noted above different weapons have different ranges, and the fact that a roadside mine has an effective range of up to 50m suggests that while penetration will vary with range the stand off armour will not be far enough from a vehicle to have a real practical effect. (ie 2.5m of space would be relevant... .5m would not).


The key is that Stand-Off distance doesn't increase the penetrating effect of a HEAT charge.

Stand off distance is a requirement for this type of warhead to be effective. Most weapons have this built in stand off range with the shape of the nose of the weapon. Unless the grill armour is several metres away from the actual armour it will have no effect on penetration except where it prevents detonation.


I actually dont understand how a PG's narrow molten stream, when projected into the interior of a vehicle, can completely defeat the target vehicle, particularly when ammunition is stored separately. Can someone explore this a bit?

The penetrator is liquid or gaseous. When it cuts through armour it spreads. It also raises the internal temperature if the vehicle to several hundred degrees C and as it is very unlikely to penetrate the other side of the armour it will splash around inside the vehicle. Many of the injuries of survivers include lung injuries from inhaling extremely high temperature gases.


They speculated that it was an RPG-22. The RPG-22 is basically the Russian's version of the LAW. Yep, the caliber is kinda small (70mm)

The early RPG-7 warheads are 73mm. BTW it was my understanding that the RPG-18 was about 73mm, while the RPG-22 was 85mm and the RPG-26 was 93mm, with the current disposable RPG-27, and RPG-28 are 105mm.

[Jippo]

Stand off distance is a requirement for this type of warhead to be effective. Most weapons have this built in stand off range with the shape of the nose of the weapon. Unless the grill armour is several metres away from the actual armour it will have no effect on penetration except where it prevents detonation.

Yes it will. Roadside mines are much larger and penetrate less than RPG warhead. RPG warhead is optimised to work with small load and penetrate a lot from a certain stand off, while mine is optimised to work over different distances in a roughly similar way.


-jippo

[GazB]

Roadside mines are much larger and penetrate less than RPG warhead.

The TM-83 is credited with an ability to penetrate 400mm of armour at up to 50m range. The penetration is 80mm in diameter. It is of course rather larger than any RPG warhead, but that is rather better than early RPG penetration performance, which was about 280mm. US Army tests showed some RPG rounds produced in Arab countries on average penetrated less than half this thickness during tests and the faults were described as fusing problems. An extra few "inches" of stand off was suggested as a remedy.

The point is that not having enough standoff distance is rather more serious for penetration than having too much standoff distance. If there is not enough space for the penetrator core to form then obviously its performance will be poor.


Needless to say that against heavy armour as on a MBT the distance is more important than in this case as the armour on a Stryker would be penetrated even with faulty rounds produced in the third world.

[flanker7]

I didn't read all the posts but I thought I offer my 2 cents.
Slant armor or whatever is called it's not designed to detonate the RPG progectiles further than optimal stand off range. It's designed to prevent them from detonating by short cerquit their warheads. The RPGs warhead is mede of two cones which if they come in contact before the piezoelectric crystal is squashed they short cirquit the fuze. That is why the c"cage" bars are in that particular distance bettwen them. Narrowrer than the RPG cone. If the RPG hits the cage with the tip of the nose first it will detonate and the thin armour of the Stryker will probably be penetrated, witless force however.
Someone probably already posted this info before so sorry for repeating

[GazB]

There is a "convergence" range for all types of HEAT and the slat armor forces explosion before round is in correct distance. So out of "focus" so to speak.


But it doesn't exactly focus like light. The shape of the cone creates the beam but aerodynamic forces would help the beam maintain its shape, rather like a SFF round.

(A SFF round or self forging fragment is commonly used in top attack munitions released from cluster bombs. It consists of a flat disc of metal with a HE charge behind it. The explosive force reshapes the metal disk to something looking a bit like a shuttle **** as used in badminton, that is travelling at very high speed... 2-3 km per second, that penetrates the thin top armour of a vehicle. It is basically aerodynamically created and maintains a largely consistant shape till impact.)

[turan8]

Perhaps you guys may not understand that the RPG already has the optimal stand off distance built in using a probe coupled with a detonator.

I made a pic to make it easier to notice on an RPG

http://www.umsl.edu/~dtdrhb/rpg.GIF

[GazB]

Perhaps you guys may not understand that the RPG already has the optimal stand off distance built in using a probe coupled with a detonator.

Already understood and shown with the cross section picture posted before.

However fusing issues remain, in that poorly made fuzes can effect the standoff distance required, and so the fixed standoff distance might be too short if the fuse doesn't work as quickly as advertised.

With the grill armour, it is not about extending the standoff range to protect the vehicle... because the standoff distance provided by grill armour is not enough to protect a vehicle with APC level armour. As mentioned ad nauseum, grill armour works by dudding the round, not by setting it off too early.

[NicNZ]

APC's have very thin walls, less ammunition and lots of empty space (compared to MBT), and thus it is not uncommon for a APC to survive multiple RPG hits.


RPG7s are relatively good because they're light, no-tech, cheap and effective especialy against soft targets

A contradiction, curses :|

[turan8]

Perhaps you guys may not understand that the RPG already has the optimal stand off distance built in using a probe coupled with a detonator.

Already understood and shown with the cross section picture posted before.

However fusing issues remain, in that poorly made fuzes can effect the standoff distance required, and so the fixed standoff distance might be too short if the fuse doesn't work as quickly as advertised.

With the grill armour, it is not about extending the standoff range to protect the vehicle... because the standoff distance provided by grill armour is not enough to protect a vehicle with APC level armour. As mentioned ad nauseum, grill armour works by dudding the round, not by setting it off too early.

Actually, if you look at the picture of the rpg stuck in the slat armor, it DOES effectively extend the range beyond the optimal standoff distance. this is because the RPG already has the optimal standoff distance built in. Any more then that, then the explosive lense becomes significantly less effective. As a mattar of fact, the RPG doesn't have an extremely large amount of explosives on board, its just that they are shaped to properly defeat armor. So preventing the RPG from getting optimal standoff distance is quite important to defeating the deadly effects of the RPG, namely spraying the interior of the vehicle with the pressurized copper liner of the RPG. This works in concert with "dudding" the round. Perhaps it wasn't discussed ad nauseum enough...

[GazB]

Actually, if you look at the picture of the rpg stuck in the slat armor, it DOES effectively extend the range beyond the optimal standoff distance. this is because the RPG already has the optimal standoff distance built in.

It would take several metres of extra standoff distance to protect an APC with maybe 40mm or armour from a warhead that can optimally penetrate 280mm of steel armour.

Less than the optimal standoff means greatly reduced penetration as the penetrator is not fully formed when it strikes the armour. Greater than the optimal standoff distance does effect performance but not as much, and certainly not enough to save an APC.


So preventing the RPG from getting optimal standoff distance is quite important to defeating the deadly effects of the RPG, namely spraying the interior of the vehicle with the pressurized copper liner of the RPG. This works in concert with "dudding" the round.

If the RPG round goes off it will most likely penetrate the armour of a stryker (or any similar APC). The Grill armour works by preventing the warhead from going off in the first place. It does not act as spaced armour.

[Herrmannek]

I want to know what exact state penetrator of the rpg is when hiting an armor and esspecialy after piercing it.. Is it plasma, gas, liquid or solid....I know it rathe impossible for anyone to have such thing, but anyone have animation,video,picture of the rpg grenade exploding "on the stand without armor"? where you can see shape of beam of the "plasma" at random ranges from the point zero?

[Stavka]

I wonder how many of those posting in this thread have served in the armored corps, mechanized infantry, or similar outfits.

Join up you morons, learn a little something about armor penetration by riding around in a tin can instead of making random assumptions.

[Herrmannek]

Join up you morons, learn a little something about armor penetration by riding around in a tin can instead of making random assumptions.
And I though that to learn something about that you need to study in politechnic kind of highier learning school :)

[Stavka]

Join up you morons, learn a little something about armor penetration by riding around in a tin can instead of making random assumptions.
And I though that to learn something about that you need to study in politechnic kind of highier learning school :)

Wasn't referring to you Herrman.

But value of "knowledge" is estimated on RL experience, and academically proven facts. Reread this thread, see if you can spot who knows what theyre talking about and who doesnt.

[nognig]

The penetration depth of the jet depends on the length of the jet upon impact, and its relative density towards that of the target material. Since the jet stretches during its flight, a better performance is obtained using a standoff between the perforating charge and the target. At larger standoff, the jet is broken into many small particulates that show much less penetrating power than a continuous jet.

[...]

The longer the jet, the greater the depth of penetration. Therefore, the greater the standoff distance (distance from target to base of cone) the better. This is true up to the point at which the jet particulates or breaks up (at 6 to 8 cone diameters from the cone base). Particulation is a result of the velocity gradient in the jet, which stretches it out until it breaks up.

Source (http://www.globalsecurity.org/military/systems/munitions/bullets2-warheads.htm)

[RGRBOX]

Good pic..

[Herrmannek]

great post nognig...

[Jippo]

[quote]It does not act as spaced armour.

But it does! If the round is detonated it will first strike the 3d surface of the slat, which it must penetrate. After this the jet is not anymore optimal.

This same thing was going on already in WW2 and especially to defeat HEAT -> Schuerzen was spaced armor just like slat armor is! Also refer to Merkava chains, T-xx rubber skirting around rollers, etc.... Especially to help with spacing out the jet.


-jippo

[GazB]

But it does! If the round is detonated it will first strike the 3d surface of the slat, which it must penetrate. After this the jet is not anymore optimal.


As repeated several times. Grill armour is effective only if it prevents the impacting warhead from detonating. If the RPG goes off then the power of the warhead will destroy the an APC like vehicle.

Real spaced armour actually consists of a sheet of armour (a grill is not armour, nor are chains, nor rubber skirts, though they all try to do the same thing). An accidental example of this is on the PT-76 which has flotation cells with armour plate inside and out so it acts like spaced armour. Combat experience has shown it is actually difficult to take out a PT-76 with a 66mm LAW, but I doubt such protection would work on a larger RPG or even the weakest ATGM missile.


Especially to help with spacing out the jet.

So if it is so effective why bother with heavy ERA? Why cover your tank in blocks with explosive inserts when a simple chain link fence will solve the problem?

The spaced side armour on the BMP-2D is to prevent penetration by 12.7mm AP rounds. T series tanks have rubber side skirts to possibly dud missile warheads and to protect the suspension from small arms and MG rounds.


Join up you morons, learn a little something about armor penetration by riding around in a tin can instead of making random assumptions.

I doubt the New Zealand army would accept someone of my age... or weight.

But just looking at what you said surely if you can only know about this subject by riding around in a tin can I would assume to find out the truth you would have to actually enter a combat zone and be hit with various types of RPG and other weapons to be sure of your facts.. If you are going to be fair and unbiased of course... but what happens if that grill armour is only capable of dudding rounds and does not reduce penetration enough to save a light vehicle like a Stryker?
The only guys who really knew would be dead wouldn't they?

[NicNZ]

Sooo go ask the dead guys! Whats the problem with that, Gaz? You prejudiced? Huh? ;)

[Jippo]

Especially to help with spacing out the jet.

So if it is so effective why bother with heavy ERA? Why cover your tank in blocks with explosive inserts when a simple chain link fence will solve the problem?

The spaced side armour on the BMP-2D is to prevent penetration by 12.7mm AP rounds. T series tanks have rubber side skirts to possibly dud missile warheads and to protect the suspension from small arms and MG rounds.

Heavy ERA is designed to defeat KE which slats are unable disrupt.

The point about slat armor is two-fold: 1. damage warhead 2. cause it to explode further from armor if the first goal is not met. What is so strange about that??? If the warhead explodes, say slat 30cm away from actual armor when hitting the jet is not optimum. If the hit is in an angle of 60 degrees from perpendicular it has a lot more time to dissipate. Hits on tanks are "always" at some other inclination than 90 "always" giving a better protection value for armor incl. spaced one.

And if only in 1/10 occasions distance given by slats is able to save crew member let alone the vehicle, I'd say it is worth having it as it weights next to nothing. :)

Btw. If you still think that the spacing has no effect, look at the slats installed on stryker for example. Why are they in most places more than half a meter from armor increasing the dimensions of the vehicle?


-jippo