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BUG: TOW-2B not working against ERA


Kingtiger

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As topic says, 2B with top attack is not working against tanks with ERA. I have fired 50 missiles against a T-72B and 100% hit but nill damage to tank, all "OK". Firing on tank without ERA is instant kill with TOW-2B.

Firing on same tank with BILL-2 (who is top attack as well) is instant kill.

Attached a small scenario and AAR that shows the issue.

/KT

TOW2B_rar.d71aea933e8c50abab416c1bc4aba8

TOW2B.rar

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Interesting, the TOW-2B uses two EFP's

http://www.msl.army.mil/Documents/Briefings/CCWS/TOW%20PEO%20Website%20Brief.pdf

I'm surprised to see in the above link they have some sort of new Counter Active Protection system for the latest TOW-2B variants. http://semanticommunity.info/Army_Weapon_Systems_Handbook_2012/Tube-Launched,_Optically-Tracked,_Wire-Guided_(TOW)_Missiles

The TOW 2B Aero is the most modern and capable missile in the TOW family, with an extended maximum range to 4,500 meters. The TOW 2B Aero has an advanced counteractive protection system capability and defeats all current and projected threat armor systems. The TOW 2B Aero flies over the target (offset above the gunner’s aim point) and uses a laser profilometer and magnetic sensor to detect and fire two ownward-directed, explosively formed penetrator warheads into the target.

So, I'm wondering if there hasn't been some sort of improvement in how the EFP's work compared to the origional 1989 version of the TOW-2B. Perhaps the two EFP's are angled inwards to strike the same area sequentially?

But this link seems to provide a hint: http://www.designation-systems.net/dusrm/m-71.html

The TOW 2B has a completely redesigned nose section, which includes two downward sequentially fired tantalum EFP (Explosive Formed Projectile) warheads,

https://rdl.train.army.mil/catalog-ws/view/100.ATSC/A127E461-9A6D-4175-A906-4F0892637D9B-1275126170054/chap1.htm

The TOW 2B has a tandem warhead that fires two explosively formed projectiles (EFPs) down through the thin upper deck armor of the enemy vehicle.

This was also interesting: http://www.dtic.mil/ndia/2013PSAR_13/hicks.pdf

However, this 16,000 frame per second test with a TOW-2B warhead going off:

http://www.funker530.com/super-slow-mo-tow-explosion/

Is interesting, look how close it goes off near the tank turret, then contrast with the photos in this report on how to handle TOW-2B's from causing problems when they are detonated next to an armor plate in the Baseline Test Configuration photo on the left side of Page 6: http://www.imemg.org/wp-content/uploads/IMEMTS%202006_Glick_paper_poster.pdf

In the sim, can we adjust our aim lower on the target to get the TOW-2B to detonate closer to the armor to achieve penetration, or have the tandem warheads go near the same area? Would it matter?

And everything you probably ever wanted to know about the ITAS launcher for the TOW, and TOW models themselves. https://rdl.train.army.mil/catalog-ws/view/100.ATSC/B4712E2A-302F-4420-8DF0-2F460B9811EA-1274307066920/3-22.32/chap1.htm

TOW 2B 9BGM-71F and 71F-1-Series) (Figure 1-21). With the advent of multiple layers of reactive armor on target vehicles, the TOW 2B was developed to attack the target from the top (fly-over-shoot-down [FOSD]). The TOW 2B contains two sensors; one identifies the iron in the armored vehicle, and the other optically determines when the target is below the missile. Both sensors are required to differentiate the target from the ground the missile is flying over.

(1) The TOW 2B contains two warheads that detonate downward when the target is identified by both sensors. This causes the two penetrators to enter the target from the top, usually through the turret where the armor is not as strong. The missile case is identified as containing a TOW 2B with the visual missile insignia, which shows the missile flying over the target.

(2) The nose of the TOW 2B missile is also an ogive configuration (crush switch), which allows the warheads to detonate in the direct attack mode. The TOW 2B has a range of 3,750 meters, and it is not available with a practice warhead.

So, it appears the TOW-2B is developed with reactive armor in mind.

The warheads in the photo are very close together: tow2bwarhed.jpg

img_load.php?pm=aHR0cDovL3Bvc3RmaWxlczEubmF2ZXIubmV0LzIwMTQwODI4XzE3Ni9kbHRqZHJoa3MxNTlfMTQwOTIxNDk3NzY5N2NmM0tjX0dJRi90b3dfMi5naWY_dHlwZT13Mg--&rf=aHR0cDovL2Jsb2cubmF2ZXIuY29tLw--

Key words in the above article are dowward almost perpendicular

EFP's vs. Reactive armor: https://books.google.com/books?id=Gm-6BAAAQBAJ&pg=PA1267&lpg=PA1267&dq=TOW-2B+EFP&source=bl&ots=sBfpbUXhbq&sig=x-cE2cyEK7zoGQQZtkFzg_vmY7M&hl=en&sa=X&ei=9B_FVL6hMoGaNsHeg6gC&ved=0CDMQ6AEwAzgK#v=onepage&q=TOW-2B%20EFP&f=false

http://www.army-guide.com/eng/product367.html

The TOW-2B (formerly the TOW lethality improvement programme) is a product improved variant with an Overflight Top Attack (OTA) capability. It is fitted with two downward sequentially fired Aerojet Electro Systems tantalum Explosive Formed Projectile (EFP) warheads and the Thomson-Thorn Missile Electronics dual-mode active optical laser profilometer and magnetic sensor fuzing device (see FITOW variant later) in a redesigned forebody ahead of the rocket motor unit.

The warheads are aligned in parallel so that they provide independent shot lines. An advanced guidance programme has been developed which is automatically initiated as the TOW-2B round leaves the launch tube. The gunner still places his cross-hairs on the target but the missile is now commanded to fly at a set height above the line of sight so that OTA can occur.

So, two independent shot lines, and sequentually fired, it would seem that the system might be able to take a one-two shot at the same location on the targets topside to enhance penetration against ERA armor, yet still penetrate the lighter turret armor underneath the ERA tiles after the first slug hits.

Edited by Invader ZIM
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http://www.army-technology.com/projects/tow/

quote: "is armed with two explosively formed tantalum penetrator (EFP) warheads. The EFP warheads detonate simultaneously, one pointing downwards, the other slightly offset to give an increased hit probability. The warhead material is designed to generate pyrophoric effects within the damaged target."

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http://www.army-technology.com/projects/tow/

quote: "is armed with two explosively formed tantalum penetrator (EFP) warheads. The EFP warheads detonate simultaneously, one pointing downwards, the other slightly offset to give an increased hit probability. The warhead material is designed to generate pyrophoric effects within the damaged target."

Yet still the EFP should be able to punch through an ERA brick without much fuss.

Its through quicker then the explosive can take effect

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reading the EFP article, in the conclusion it says "the penetration capability of the fragments was reduced from 87mm to 20mm for both types of panels.

in other words, the penetration power was reduced with 77%.

this is even worse than for HEAT, where you expect a 50% reduction in penetration power.

also, the article states that the EFP is slower than a HEAT jet.

it lists a velocity of 2300m/s. compared to the quickest portion of a HEAT jet which is in the region of 7000m/s.

in summary as long as the explosive in the ERA is not degraded by weather and age, even light ERA should be able to deal with EFPs.

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The article used a half size 80mm and 175 gram test example and reference design compared to the TOW-2B, BONUS, and SADARM warheads it says though.

http://en.wikipedia.org/wiki/Shaped_charge

The EFP is relatively unaffected by first-generation reactive armor and can travel up to perhaps 1000 charge diameters (CDs) before its velocity becomes ineffective at penetrating armor due to aerodynamic drag, or successfully hitting the target becomes a problem. The impact of a ball or slug EFP normally causes a large-diameter but relatively shallow hole, of, at most, a couple of CDs. If the EFP perforates the armor, spalling and extensive behind armor effects (BAE, also called behind armor damage, BAD) will occur. The BAE is mainly caused by the high-temperature and high-velocity armor and slug fragments being injected into the interior space and the blast overpressure caused by this debris. More modern EFP warhead versions, through the use of advanced initiation modes, can also produce long-rods (stretched slugs), multi-slugs and finned rod/slug projectiles. The long-rods are able to penetrate a much greater depth of armor, at some loss to BAE, multi-slugs are better at defeating light or area targets and the finned projectiles are much more accurate.

The use of this warhead type is mainly restricted to lightly armored areas of main battle tanks (MBT) such as the top, belly and rear armored areas. It is well suited for the attack of other less heavily protected armored fighting vehicles (AFV) and in the breaching of material targets (buildings, bunkers, bridge supports, etc.). The newer rod projectiles may be effective against the more heavily armored areas of MBTs. Weapons using the EFP principle have already been used in combat; the "smart" submunitions in the CBU-97 cluster bomb used by the US Air Force and Navy in the 2003 Iraq war employed this principle, and the US Army is reportedly experimenting with precision-guided artillery shells under Project SADARM (Seek And Destroy ARMor). There are also various other projectile (BONUS, DM 642) and rocket submunitions (Motiv-3M, DM 642) and mines (MIFF, TMRP-6) that use EFP principle. Examples of EFP warheads are US patents 5038683[31] and US6606951.[32]

http://en.wikipedia.org/wiki/Explosively_formed_penetrator

As a rule of thumb, an EFP can perforate a thickness of armour steel equal to half the diameter of its charge for a copper or iron liner,[7] and armour steel equal to the diameter of its charge for a tantalum liner, whereas a typical shaped charge will go through six or more diameters.

The penetration is proportional to the density of the liner metal; tantalum 16.654 g/cm3, copper 8.960 g/cm3, iron 7.874 g/cm3. Tantalum is preferable in delivery systems that have limitations in size, like the SADARM, which is delivered by a howitzer. For other weapon systems where the size does not matter, a copper liner of double the calibre is used.

Patent: http://www.google.com/patents/US5038683

High explosive assembly for projecting high velocity long rods

Dated 1989

http://www.google.com/patents/US6606951

public .mil source, page 11: https://acc.dau.mil/adl/en-US/528027/file/65354/2012%20Weapon%20Systems%20Book%20pdf.pdf

TOW-2B Warhead: Two EFP warheads weighing approximately 1.4lb each. Warhead liners are of tantalum, explosive is LX-14

November 2003 TOW manual public distribution document:

http://www.scribd.com/doc/14251133/Tow-Weapon-System#scribd

Section 5-6, engaging T-80 with reactive armor:

For example, if the target is a BTR-60 or BMP-1, the squad leader may command, TOW 2; if the target is a T-80 with reactive armor, he may command, TOW 2B.

It just seems counterintuitive if in the sim the TOW-2B is ineffective against reactive armor, yet the manual for the weapon specifically mentions the -2B for a T-80 with reactive armor.

Edited by Invader ZIM
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reading the EFP article, in the conclusion it says "the penetration capability of the fragments was reduced from 87mm to 20mm for both types of panels.

in other words, the penetration power was reduced with 77%.

this is even worse than for HEAT, where you expect a 50% reduction in penetration power.

also, the article states that the EFP is slower than a HEAT jet.

it lists a velocity of 2300m/s. compared to the quickest portion of a HEAT jet which is in the region of 7000m/s

Consider that this one might be that of the BONUS ammo. Which has a different setup then the EFP of TOW-2B.

Esp. with missles that a designed to detonate only a few meters above target...2300m/s is the very low part of the spectrum. Ok, they have used one of the fastes explosives available...but you can be much more effective with some tweaks ;-)

The 70% value is true for that one in the paper.

The 2B warhead has more punch to begin with. And the remaining power after ERA is defo big enough to kill a tank-roof.

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The article used a half size 80mm and 175 gram test example and reference design compared to the TOW-2B, BONUS, and SADARM warheads it says though.

http://en.wikipedia.org/wiki/Shaped_charge

http://en.wikipedia.org/wiki/Explosively_formed_penetrator

hmm, wikipedia, or a scientific document. so hard to pick..

and the TOW2B in steel beasts penetrates 300mm. nearly twice the missile diameter, and over twice the warhead diameter. as for increasing the length, it means reducing the diameter, making it more susceptible to ERA.

same as the experimental document.

November 2003 TOW manual public distribution document:

http://www.scribd.com/doc/14251133/Tow-Weapon-System#scribd

Section 5-6, engaging T-80 with reactive armor:

It just seems counterintuitive if in the sim the TOW-2B is ineffective against reactive armor, yet the manual for the weapon specifically mentions the -2B for a T-80 with reactive armor.

one shot, one kill against T-80U with TOW-2B

tgqQEam.jpg

i'll just add they don't specify which T-80. could be the T-80B.

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This topic seems to come up every couple or years. I read quite a bit on this subject in the past when we, internally, wondered the same thing. The TOW-2B works as it should; the two warheads are simultaneous and at slightly different angles (so it is not tandem) to increase likelyhood of a direct/lethal hit and not perpetual hits in the engine deck, etc. Can it penetrate ERA? Yes. Will it have enough power to still kill the vehicle? Usually, but that primarily has to do with the fact that it usually misses the ERA altogether.

They cannot put ERA over the entire roof and the two slightly different angled EPFs creating two different impacts usually make it a moot point (apparently). I am sure you would have the occasion TOW-2B defeated by ERA, but in this case in SB you would usually get some sort of damage from the impact.

Edit: I see that Dejawolf answered this earlier -- I only read the first post when I replied here. It seems he remembered all the internal research on the matter too. :)

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Thanks for that info Volcano.

In the AAR's when you use the TOW-2B, it shows a single vertical line into the target. But are you saying that in reality the simulation is actually calculating two separate projectiles striking two different spots on the vehicle?

Well no, not quite. :redface:

It is abstract at the moment, for the sake of simplicity. IIRC we represent the double EFP by having a single near perfect detonation on vehicle center each time. :)

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Okay, that's interesting and it might explain the results we see sometimes. Using KingTiger's scenario it took me 13 TOW-2B hits to destroy the Gen 1 ERA T-72B tank. Looking at the AAR, when more than a few hits are shown going into the same ERA tiles on the roof near the center, it's not counted as a kill, nor is any damage given. However, since the other warhead isn't modeled going to another spot there isn't another chance for the weapon to penetrate. Hit 13 strikes an area without ERA and counts the kill.

Thanks again for the explanation.

Here's my AAR from KingTiger's test scenario.

56e83d1207dcf_testTOW-2BvsReactive_zip.6

test TOW-2B vs Reactive.zip

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Hmm, could be why a T-72B laughs at Katie's puny attempts to destroy it.

:men_ani:

If sacrificial armour is not being sacrificed = T-72B Stronk!!

:)

No, not yet. but perhaps in the future. we've been trying some fancy stuff with ERA bricks, but have yet to test it properly.

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Maybe just setting the penetration of the TOW-2B to the same as BILL or BILL-2 at 600mm top attack to compensate for the missing 2nd warhead for now.

After running the test the TOW-2B feels like this. https://www.youtube.com/watch?v=F5zFasPrRRw

:D

http://www.army-technology.com/projects/predator_kestrel/

The missile is normally used in top attack mode, using a top attack trajectory and laser and magnetic proximity sensors to fire the warhead directly onto the vulnerable top of the tank where the armour is weakest. The explosively formed penetrator warhead is made by Aerojet and is developed from that used on the Raytheon TOW 2B missile. The warhead can penetrate explosive reactive armour (ERA).
Edited by Invader ZIM
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So does SB count any expended ERA bricks as expended?

Not yet.

With well-contained heavy ERA modules like Kontakt-5 this is perfectly justified. The likelihood to hit the exact same module again is small.

With Kontakt-1 light ERA, this is a different story. Footage from Syria suggests that an RPG hit is sufficient to not only detonate the one tile that received the HEAT jet, but to make surrounding tiles fall off simply due to the blast wave.

You'll see it when you see it in SB.

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Maybe just setting the penetration of the TOW-2B to the same as BILL or BILL-2 at 600mm top attack to compensate for the missing 2nd warhead for now.

After running the test the TOW-2B feels like this. https://www.youtube.com/watch?v=F5zFasPrRRw

:D

http://www.army-technology.com/projects/predator_kestrel/

sure, all HEAT warheads can penetrate explosive reactive armour as well. ERA doesn't work like conventional armour. it reduces the warhead by a certain percentage. so there always needs to be a decent thickness of backing armour. even worse, ERA is most effective at about a 50-70 degree angle with protection effects worsening at shallower angles. stated protection levels for ERA is usually listed at this angle.

ERA in the kontakt-1 blocks is "pre-angled" like so:

2c20.jpg

to increase the effectiveness even at unfavourable hit angles.

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