NationStates Jolt Archive

Panzerkampfwaggen XI BredtSverd

http://img233.exs.cx/img233/1993/tank27mg.jpg

Armor:
Due to the overriding cost of the Muwatallis' 'buckyball composite' armor, and because this cost is what caused the shortages of armor in the Macabee armed forces it was decided that a much cheaper, yet still completely modern, armor was needed, and although it would still be expensive relative to other tanks it would be considerably cheaper than the billion dollar buckyballs. Consequently, the armor would be a heavy conglameration of Russian/Soviet technology, Israeli technology, and American technology. The overriding armored layer is one of Kontackt-5 ERA, which is said to give an RHA value of 600mms against HEAT and 250mm against APFSDS with an armored mass of three tons. So, there's actually two layers of Kontackt-5 ERA bricks merged as one, giving the armor a weight of a total of about ten tons. The second layer is composed of eighteen millimeters of Modular Expandable Armor System (MEXAS),which equates to around three thousand millimeters of RHA armored value. The final layer is made of a Chobham Composite armor, who's exact materials remain secret, although it's rumored by a few of the engineers that it has mixed layers/fibers of plastic, ceramics, titanium boride, depleted uranium, et cetera. Finally, on top of the Kontackt-5 ERA armor the Pz. XI also uses the newly designed 'electric amor'. The new electric armour is made up of a highly-charged capacitor that is connected to two separate metal plates on the tank's exterior. The outer plate, which is bullet-proof and made from an unspecified alloy, is earthed while the insulated inner plate is live. The electric armour runs off the tank's own power supply. When the tank commander feels he is in a dangerous area, he simply switches on the current to the inner plate. When the warhead fires its jet of molten copper, it penetrates both the outer plate and the insulation of the inner plate. This makes a connection and thousands of amps of electricity vaporises most of the molten copper. The rest of the copper is dispersed harmlessly against the vehicle's hull. But despite the high charge, the electrical load on the battery is no more than that caused by starting the engine on a cold morning.

Fire and Control System:
http://www.gdcanada.com/company_info/images/chart.jpg
The new fire and control system present on the Pz. XI, dubbed 'Brass', is the new top notch of said systems, developed by General Dynamics (Canada) and expanded upon by Macabee engineers. It includes Multi-Role Sensor Suite, Multi-Sensor Integration, Integrated Sensor/TA Suite, Virtual Immersive, Environment (AVTB)\, Neuroholographic ATD/R, Immersive Visualization. Moreover, the new system has both a low altitude RADAR and LIDAR system which has capabilities of tracking and giving firing solutions for up to twenty different targets at up to four thousand meters for the LIDAR and up to eleven thousand meters for the RADAR (although, of course, a gun doesn't necessarily have the power nor the type of shell to reach that far, and of course, that doesn't mean that the area between you and the enemy tank if full of large rocks that can disrupt your shell and its vector). The LIDAR uses a gaussian transmitter, which is right now the most advanced LIDAR transmitter developed by the United States. Of course, this fire and control system also uses thermal imaging, and of course, infra-red imaging.

Main Gun:
The Panzer XI uses a 120mm ETC cannon. Although there were proponents of following suit with other nations and putting up to 200mm ETC cannons it was finally decided that such a decision would be unintelligent as it would mean, most importantly, that the turret would rotate slower and rate of fire would be much slower (concerning turning the turret, actually firing, and loading the shells). To make the turret turn quicker the turret and the chassis are divided in two by a central gyro circular sheet of composite metals, using McPhearson strut like bars, interwoven in springs (much like the shocks on your cars) and then smaller gyrating bars, to make the movement hydraulic, consequently, making it much faster. As do other Macabee tanks there are also small "R rings" inside the barrel which are springs measuring nanometers in size which reduce the kickback post-firing as well as muzzle flash.

http://img233.exs.cx/img233/9163/kbm2l1tu.jpg

Other Systems:
The Shortstop Electronic Protection System (SEPS) is an RF Proximity Fuze counter measure. The Shortstop battlefield electronic countermeasures system is capable of prematurely detonating incoming artillery and mortar rounds. It counters the threat of RF Proximity Fuzed munitions by causing them to prefunction, to protect friendly ground troops, vehicles, structures, and other equipment under fire. The SHORTSTOP system was originally produced as a Quick Reaction Capability (QRC) product in support of Desert Storm. A request for information (RFI) was received from ARCENT addressing available countermeasures for indirect fire munitions utilizing proximity fuzes; such as those found in artillery, mortar, and rocket munitions. Whittaker Corp. in Simi Valley, CA built the system for PEO-IEW during the Gulf War in response to the artillery threat posed by the Iraqis, but the war ended before Shortstop could be deployed. The system could reduce casualties to ground troops by as much as 50 percent during the initial stages of an enemy attack. These prototype systems were subjected to a minimal amount of environmental testing in preparation for deployment. After Desert Storm, the system was subjected to extensive live fire testing in the desert at Yuma Proving Grounds and evaluated by the TRADOC Analysis Command (TRAC) and the Dismounted Battlespace Battle Lab. The SHORTSTOP, AN/VLQ -9 or -10, systems demonstrated, in testing, the ability to significantly enhance survivability of troops and high value assets from indirect fire, proximity fuzed munitions. Reports of more than 5,000 live artillery and mortar round firings against Shortstop in tests at Yuma Proving Ground, Ariz., indicate that the system is 100 percent effective against selected weapons. The test rounds were fired singly and in barrages, with none reaching their intended target, test officials reported. The prototypes were deployed for a limited period of time in Bosnia and were returned to contingency stock in 1997. To meet urgent operational requirements for deployed forces, the 3rd Army Commander on 11 Feb 98 requested 12 Shortstop Electronic Countermeasure Systems. These systems were readily available as a near term loan that only required funding to train operators and purchase some fielding and maintenance related items. HQDA approved the release for immediate deployment, requesting AMC execute the action that was subsequently completed by CECOM's Project Manager for Firefinder. The QRO supported delivery and fielding of these systems by coordinating the necessary arrangements for deployment of a two-man New Equipment Training Team (NETT) from CECOM. The NETT departed on 25 Feb 1998 with the equipment (acting as couriers) on a C-5 Cargo flight out of Dover AFB. The SHORTSTOP system training, checkout and positioning was completed by the CECOM NETT 20 March 1998. Packaged in a suitcase-size case and fitted with a small multi-directional antenna, the Shortstop system can be activated and operational within seconds. Shortstop's passive electronics and operational features make it impervious to detection by enemy signal-intelligence sensors. In the near future, Shortstop will shrink in size, down to 25 pounds. Whittaker is currently under contract to build three new, smaller versions: manpack and vehicle units, as well as a stand-alone unit.

FCLAS is comprised of a sensor and short range grenade launcher, loaded with special fragmentation grenades with delay fuses set to intercept the incoming threat at a range of approx. 5 meters from the protected vehicle. The actual initiation of the explosive charge is triggered by a side looking RF proximity fuse which senses the incoming projectile as it passes nearby. The explosion forms a vertical, doughnut shaped fragmentation effect that kills the passing threat but does not effect the protected vehicle. The system's target weight is 140 kg., to enable deployment on light vehicles. Each grenade is equipped with a forward looking radar mounted on the exposed tip of the grenade. Each of the FCLAS munitions has such an integrated radar, which forms a complete sensor, monitoring a protective hemisphere around and above the vehicle. The Army hopes to get a prototype system of FCLAS for testing in 2004 and an operational system, which could protect against RPG threats, deployed with Bradley, Stryker and Humvee

The Panzer XI also has a small CIWS system resembling a smaller Phalanx, however, using a seperate gaussian transmitter with a range of about two hundred meters to track incoming anti-tank guided and unguided missiles. The CIWS, or ACIWS, is automated and has a three hundred and sixty rotational view.

Engine:
The Panzer XI uses a 1,800 horsepower diesel engine which gives the Panzer XI a maximum on road velocity of forty kilometers per hour, which is really all that is needed for a tank the size of a Panzer XI.

Crew: 4 (Commander, Gunner, Loader, Auxilary Machine Gunner/Driver)
Weight: 80.4 Tons

Cost:8 Million USD
Production Rights: Not available


[Differences from the last tank are the 'buckyball composite' armor, the hydrogen fuel cell tank engine, I took off the anti-mine laser system because I can just use the old fashion scorpion which costs infinitely less mulah, and I took off the DREAD and just decided to go with a Phalanx type system.]

Pic of the Track:
http://img233.exs.cx/img233/949/wc18cc.jpg

[There done]

OOC: Thankyou, thankyou, thankyou for not using buckeyballs or hydrogen fuel cells. This is actually quite good. I agree that 200mm ETC is just silly... even 155mm might be a bit OTT, but *shrug*.

This tank is, overall, rather nice.

OOC: Thankyou, thankyou, thankyou for not using buckeyballs or hydrogen fuel cells. This is actually quite good. I agree that 200mm ETC is just silly... even 155mm might be a bit OTT, but *shrug*.

This tank is, overall, rather nice.

[OOC: Thanks. Yea, the 155mm is also big, and perhaps it would have been better to use a 120mm Rhinemettal or something like that..but oh well.]

Nicely done =) I don't even need to scream about the gun because 80 metric tons should be sufficiently big to take the recoil by NS standards... though it would still flip IRL.

Couple of issues. You might want to make the Kontact the outer layer of armour as, after all, it's explosive. If you did do this, it wasn't clear from the description. I'm also wondering how vaporising a semi-molton stream of metal pouring into the tank's armour when it's already acheived a bit of penetration will actually improve the situation, or even how enough of the armour will survive that initial penetration to engage the electrical armour. not saying it won't work, mind you, but it seems a little odd.

I really think you should go over that MEXAS pamphlet again... I'm having trouble believing the figures you're siting. MEXAS protected vehicles exist today and have been killed by HEAT weapons... how is this posisble if 3000mm effective penitration are required?

One other worry I have... your tank is protected exceptionally well from HEAT weapons, but HEAT is currently an ineffective weapon to use against MBTs... almost all heavy AT weapons are KE based.

Shortstop will be completely ineffective against artillery with light based proxi-fuzes

Who is going to drive the tank?

Nice work Macabees. I am seeing that you are very good at working with military equipment, and hope to see some even better equipment in the future. I was wondering, is there any possible way our two nations could perhaps develop a joint operation for military equipment?

Nicely done =) I don't even need to scream about the gun because 80 metric tons should be sufficiently big to take the recoil by NS standards... though it would still flip IRL.

Couple of issues. You might want to make the Kontact the outer layer of armour as, after all, it's explosive. If you did do this, it wasn't clear from the description. I'm also wondering how vaporising a semi-molton stream of metal pouring into the tank's armour when it's already acheived a bit of penetration will actually improve the situation, or even how enough of the armour will survive that initial penetration to engage the electrical armour. not saying it won't work, mind you, but it seems a little odd.

I really think you should go over that MEXAS pamphlet again... I'm having trouble believing the figures you're siting. MEXAS protected vehicles exist today and have been killed by HEAT weapons... how is this posisble if 3000mm effective penitration are required?

One other worry I have... your tank is protected exceptionally well from HEAT weapons, but HEAT is currently an ineffective weapon to use against MBTs... almost all heavy AT weapons are KE based.

Shortstop will be completely ineffective against artillery with light based proxi-fuzes

Who is going to drive the tank?


Understood, thanks a lot..I'll update it in a bit, especially the armor bit. As for the tank driver, sorry, that's the weapon's management person - the commander's job sorta overlaps with his also, in reference to system's management.

Nice work Macabees. I am seeing that you are very good at working with military equipment, and hope to see some even better equipment in the future. I was wondering, is there any possible way our two nations could perhaps develop a joint operation for military equipment?

That would be awsome. Whenever you want!

I'll telegram when I decide for a time to do so. Also, I just released my Jaeger MkVII, if you wish to see my latest development in MBTs, here: http://forums.jolt.co.uk/showthread.php?t=404532

Another nice piece of armor! I like the engine.

[Note for all: Also, I toned down the gun a bit to a 120mm ETC. and...


MEXAS
MEXAS density is ~1.7g/cc and reactive elements are reported in the construction with a strenght of 2.5 GPa, not many materials are that strong but Boron Carbide could fit the bill.
B4C has a mass of 2.55g/cc and ME vs shaped charges of ~ 4.0...leading to a space effectiveness of ~ 1.3.

Now a mixture of CaCO/GAP and B4C should have a density of 1.7-1.8 g/cc [2.55g/cc+1.0g/cc ÷2]. Some thing with the density of CaCO/Gap should have an effectiveness of ~ 0.7 [space effectiveness] so a average of B4C & CaCO/GAP should be ~ 1.0 spaced effectiveness...

The ME should be 7.83/1.7= 4.6.

But the CaCO/GAP is reactive and generates a considerable improvement in effectivenes because this reactive forces the steel plates apart...using the VM-11 paper as a guide the ME of steel foam is ~ 3.3 while the value for steel CaCO/GAP is ~ 10.0...meaning this reactivity tripled the effectiveness of the sandwich...

If this same reactivity is applied to the above B4C & CaCO/GAP sandwich we end up with ~ 14:1 Me.

Now in this paper there were reactive elements that were tested with thin explosive layers to enhance the bulging effect on the outer steel plates...these ranged from 4-6 times the base values and if these super reactive forces are applied to the MEXAS model thats 4.6 x 4-6 or ME of 18:1 -28:1.

The paper showed that MEXAS @ 15° offers as much protection as ERA @ 60-70°. If you take Blazer this is two 2-3mm steel plates and a couple of mm of explosives [density ~ 1.8g/cc?]...any way thats ~ 6mm steel mass @ 60-70° or 12-18mm steel...the ME of these ERAs are reported to be ~ 20:1 meaning this resistance is ~ 240-350mm. Thus MEXAS with a steel mass of ~ 7mm is as effective as >250mm RHAe or a ME of 36:1!!!!

Heres the crunch...studies of bulging plates show that plate speed is the key. Well if the above chemical reactive forces can 'bulge' a plate sufficently to tripple quadruple its effectiveness , image how effective they would be on a small ceramic [B4C ]nugget? Rosenberg and Dekel wrote several papers on the parameters of this bulging prossess...it was clear that if you increases the interlayer or reduced the thickness of the outer steel plate [mass], the plate bulging velocity shot up [going from 200-800m/s in some cases].

Could be that instead of tripple its 6-8 times the ME against shaped charges? That would be an ME of ~ 32-37 .

KE resistance would suck...incomparison but it could still be overall very effective against small diameter projectiles....

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A recent paper in the Int.J.Impact Engng [Vol26,pp831-841] Webber et al ,examined the KE resistance of layered ceramics [AiN] with thin interlayers [PMMA] mounted on RHA. In these test the resistance of AiN compared to RHAe [~400BHN]was tested ....these targets had plate diameters to the subscale penetrator diameters of 9:1 to 14:1, which is very close to what I believe the approxiamte ceramic dimensions are in modern tanks armor.

In the tests the reference RHAe penetration was 90mm while the block of AiN resistance was 0.98 Te [thickness effectiveness]. That means 10cm of AiN could be expected to offer the equivellent of 98mm RHA. When the same thickness of ceramic was divided into thinner plates [change t/d from 7:1 to 0.6:1]. The resistance went from 0.98 Te to 0.9 showing that large reduction in t/d reduces resistance only by 9%. When the same target had thin plexiglas sheets added inbetween each of the 12 thin ceramic plates, the resistance was reduced to 0.86 T/d.

This is a reduction of 12%, but with the dilution of the target with lower density interlayers [ 3.26g/cc for AiN & 1.2g/cc for PMMA], the effective resistance over all didn't change much.Because thicker over all array could be constructed with the same armor mass.

If 10cm of steel mass was devoted to the insert effectives, a straight AiN insert would amount to 24cm thick, with a overall KE resistance of ~23.6cm RHAe. If the same armor mass was devoted to a AiN /Plexiglas multi layered target [2.98 g/cc average density], then the array thickness increases to 26cm .The effectiveness over all is reduced to 22.6cm RHAe...this is a reduction in resistance to ~96%.

So why is this practice reported to be done? Firstly the paper reports that constructing ceramics in blocks thick enough for heavy tank targets is very expensice. If the same thickness was composed of thinner plates this would reduce cost considerably. Since armor is secondary to firepower/FCS cost , this is not a small consideration.

In addition these targets where struck at normal impact angles, at angle the resistance may improve. In a paper from the institute @ Chobham [Hohler etal int.J.Impact Engng Vol-26 , pp 333-344] , layered ceramic targets @ 0° & 60° showed that atleast for subscale models, the @ 60° layered ceramic [Alumina AD-97] steel target resistance was higher than the same LOS target thickness @ 0° impact angle. In otherwards something in the layering at angle helps to defeat long rod penetrators.

However there may be another reason why multilayers with interlayers is practiced ,because it improves shaped charge resistance.

In a paper by Hornemann & Holzwarth [Int.J.Impact Engng Vol 20,pp375-386], various layered ceramic steel targets where fired on by 5cm subscale shaped charge warheads .In these tests at normal impact angle the reference penetration into RHA was 216mm while the optimum ceramic [AD-92]/steel resistance was 116mm suggesting an overall Te of 1.8 RHAe. Another target was the same construction with a rubber layer inbetween each ceramic tile [ ratio 1 rubber to 6 ceramic , similar to the AiN tests mentioned above].In this target the resistance worked out to 1.73 Te [125mm].The cross sectional density of the two different arrays was 3.5g/cc and 3.2g/cc, thus if we had 10cm of steel mass for an insert the straight AD-92 target could offer 22cm ceramic thickness for an effectiveness of ~40cm RHAe. The Ceramic Rubber target should have a thickness of 24cm and an effectiveness of ~42cm RHAe.Thats about a 5% improvement in resistance.


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VM-04 "Analysis of Active Protection system: When Athena meets Arena" Wey , Fleck & Chanteret.
Reportedly Arena was first introduced in 1992 and it incorperates
A MM wave radar for incoming missile detection
32 x'focused grenade' for hitting inbound missile
A control unit.
An accompanging diagram shows radar scanns 50m radius around tank from mast mounted MMwave radar and intercept occurs a few meters from the tank.

Simulation of this shows a 150mm grenade is needed to get sufficent 'spray of fragments' powerfull enough to destroy a missile.. In theory a single fragement hit should generate 70% kill while two hits should accumulate a 90% hit chance.

Further simulation reveals that % of hits as follows

narrow azimuth and wide azimuth simulations where tried with a grenade detonated with to cover a 10° azimuth angle with no repeats while the second grenade covered 20° allowing two grenades to cover each sector with drop in intercept probablity.

The results are below...

chance of a hit on a missile approaching


Hull Turret from the azimuth in question.

Single 10° 85%[4.8m 4 fragments] 90%[2.6m 10 fragments]
overlaping 20° 50%[5.5m 1 fragment] 90%[2.1m 6 fragments]

Clearly some precise detonation is needed since a change of detonation angle reduces the number of fragments dramatically [ ~ 3-4 fragments] and lower hit chance... 1 fragmemt = 50% over hull compared to 4 fragments resulting in 85% hit.

These are the results of lab simulations [controlled] and battlefield conditions should bring these figures down dramatically.For example its reported that this system doubles the effectiveness of the tank...which can be interpeted as 50% hit chance against incoming missiles.This is probably a good ball park figure to work with when estiamting the effectiveness of these active defence systems.

In WM-01 "Active Protection against KE-rounds and shaped charges at short distance" M- Held, reports that Droz only covers 40°either side of the gun while Arena covers 340°

VM-14 "Defeating Active Defence Systems by Double firing of missiles." M-Held, reports that Drost fragment covers only ± 0.5m meter area while Arena is ± 2m either side of the grenade direction.

Held also notes that the sensor will have dead time thats 1-3 seconds that can't get a detection so firing two missiles from the same launcher should be an effective way to ensure second missile reaches target.[Alternatively two launch systems within 10m of each other can diplicate this if some precise system can 'similtaneously fire' the missiles].Held estiamtes that if the system is automated it can place the second missile 20m behind the first giving enough seperation to clear the debri field before impacting the target, stationary or on the move.

Held suspects that BMP with 'Khrizantema' missile system may well already have this capability.



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In a paper recently published in the Int.J.Impact Engng [Vol-26 pp 735-744] A group of Russian researchers [Svirsky etal from Russian Federal Nuclear Center] studied the effects of spaced armor on 120mm 100mm & 46mm shaped charges....the results are quite surprising!

They analyse post penetration xrays radio graqphs of thin spaced plates and found the same large post penetration jet disruption zone that I reported about before [ the 14mm thick steel aluminum sandwhich causing a 28-30cm disruption zone in the jet]. They report this segment of the jet has very poor penetration.

Any way they tested 120mm shaped charge against a spaced armor target with 200mm steel in three plates @ 7 CD standoff and measured the residual penetration at 77-80% of the reference penetration. Which wasn't given, but it should have be 840mm, thus Pexp should be 65-67cm.So the array offer 19-17cm or 0.85 to 0.95 LOS thickness. Not very good idea!

The next test was a 100mm shaped charge fired at a 38mm spaced steel aluminum array @ 5.8 total diameters standoff, infront of RHA semifinite target . This resulted again in 80% reduction of penetration into the reference material. Again assuming 7 CD reference penetration, the spaced plates accounted for 132mm of RHA [ 132/35 ] , so the array was ~ 3.8 times as effective as its LOS/Te values suggest.Not bad at all and consistant with previous findinds [~ 3 x LOS for spaced a single steel plate].

Next target was a 100mm shaped charge fired at a 62mm two plate spaced steel array @ 6.8 total diameters standoff . This resulted about 70% reduction of penetration into the reference material. Again assuming 7 CD reference penetration, the spaced plates accounted for 204mm of RHA [ 204/62 ] , so the array was ~ 3.2 times as effective as its LOS/Te values suggest.

Finally they tested 46mm shaped charge @ 2.2 CD standoff into RHA and got a penetration of 157±7mm ( 3 shots) [ 70° copper cone 1mm thick liner , with a 6.6 km/s tip V and 350mm break up distance].Next the placed a 1mm plate 0.5d from the reference RHAe and this reduced the penetration to an astonishing 124±5mm penetration[ 3 shots]....again about a 20% reduction in penetration.

It seems that the average resistance offered by a spaced armor array -reguardless of its thickness - is about 22% average reduction in modern shaped charge penetration [20-30% range].Infact it seems to suggest that the thicker the spaced plate the less effective it is at defeating shaped charges.

This effect is confirmed by Hornemann & Holzwarth [ Int.J.Impact Engng- Vol 20 pp 375-386]. The reference penetration against a straight RHA target was 215mm while penetration into spaced target with 72mm thick spaced plate was 200mm and a similar target with 20mm spaced plate resulted in a penetration of 195mm ...in other words the 72mm spaced plate accounted for 87mm resistance [1.2 x LOS] , while the 20mm plate resulted in 40mm resistance [ 2 x LOS].

So all those thin boxes and side skirts placed on the sides and rear of AFVs do offer a considerable increase in resistance. Check out Chieftain tank, by Mk 13 the side profile is >80% covered in boxes and side skirts and Still brew... Thus even the side turret [ 15cm RHA ] should be able to boost the resistance against basic RPG-7 , by 6cm to ~ 21cm....assuming those boxes are empty.The above test figures are for modern jets where increase in the standoff alone should not reduce penetration atall. But early RPG -7 was 'none precision jet' so with the standoff this should increase resistance by ~2 diameter or + 15cm , bringing the average side turret resistance to ~ 36cm.

Against a 'precision charge' [RPG-7V],the resistance should be down ~22cm due to lack of any significant standoff reduction at this level. However if the storage boxes are full of material with an average density of plastic that should bring the total side turret resistance to ~ 35cm . Only difference is that it should be equally effective against both 'precision and none precision' jets .


Despite the impressive reduction in penetration provided by the most energetic armour, the residual penetration is still enough to penetrate the underlying hull armour any of the APC/IFVs out there. So RPGs will be able to penetrate MEXAS type targets with 73mm warheads (a mere 365 mm basic penetration in this case, right?), let alone the many generations of improved grenade that followed.

Damage will be mitigated, compared to the unprotected vehicle, but it will happen nonetheless, and it doesn't take very much residual RHA piercing power to kill a soldier, or detonate stowed ammunition in the path of the jet.

Definitely looking forward to those papers!

I agree with you premise how ever the way I understand it the current armor is probably resistant to most RPG-7V strikes...thats to say if Herr Diesenroth figure are to be taken at face value , the 20mm Mexas applique @ 10-20o is as effective as ERA @ 60o. In the other paper the 14mm ERA @ 60o offered > 11 times the LOS resistance so this suggest MExas @ 10-20o offers at least the same.

Thats LOS 21-22mm x 11.25 = 24-25cm...add the base armor [~ 15mm RHAe] = ~ 26cm RHAe. From the other paper on liners a simple thin PE liner should reduce kill % 10%, while other papers in that symposium suggest better materials will do better [ ~ 20%?] thats an additional 4-7cm possible resistance. This brings the potential side hull resistance up to 30-33cm from straight on ....from 30o off angle [ more likely case] thats 35-38cm effective RHAe.

OK I realize this is mostly calculation, but if this is totally correct it means a 16,000-17,000kg AFV can have the allround protection of a 55 ton Chieftain [ with all those lovely storage boxes and skirting plates]....any way you cut it thats a considerable increase!


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In another paper on various energetic armors [TB61 Combination of inert and energetic materials in reactive armor against shaped charge jets . Holzwarth & Weimann] , they test fired 73mm jets into various energetic armors mounted ahead of a 230BHN semi infinite target and the following figures where generated.All arrays were 2mm steel 10mm interlayer 2mm steel and the angle of array was 60°, thus the array LOS was 28mm.

Preference DOP = 365mm thus difference /28mm = array RHAe
S-rubber-S = 280mm = 3 x LOS thickness
S-GAP-S = 280mm = 3 x LOS thickness
S-Gap+R-S = 250mm = 4.1 x LOS thickness
S-Gap-exp-S = 190-120mm = 6.2- 8.8 x LOS thickness

S=Steel
GAP=polymer
Gap+R= GAP + CaCO3 or GZT
Gap+exp = GAP + explosive

Now it was shown that the GAP material is forced to undergo a additional chemical reaction when a small layer [1mm] of explosive is involved resulting in P of 150-170mm or a thickness effectivness of 6.6 to 7.7. This is much more than the GAP with the CaCO3 , which generates some gas bubbles in the array, which under the pressure of impact enhance the distruption of the jet.

I can only conclude that the Mexas must have found a way of doing this same kind of thing without the thin explosive layer!

Its becoming apparent that in addition to the bulging of the plates ,the expanding gases in the ERA sandwich maybe interfering with the jet as well.


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American 76mm M-32 gun with M464 APFSDS round ; This is 1.63 kg tungsten alloy penetrator with a MV of 1400m/s with a Vdrop probably similar to M-500 round of 76m/s/km with an L/d of 15:1 and a diameter of 20.6mm or 309mm length . Such a rod would be 103cc volume or 1.80 kg @ 17.5 g/cc density, but if the nose and tail had a ‘truncated form’ the volume could be reduced to the 93-95cc volume that a 1.66kg , close to the 1.63 suggest weight . Using Andersons the values are – 0.74 [ L/d effect] , x 1.16 [scaling] and plus 1. 2 d semi infinite conversion @ 0° and 2.4 d @ 60°….that’s + 24mm & + 48mm and the 60° penetration is a line of sight penetration. Going on these imputes the penetration should be …


Muzzle [ 1400 m/s] = 0.84 x 31cm = 28 cm ± 4cm @ 0° & 31cm ± 4cm @ 60°
1000m [ 1324 m/s] = 0.745 x 31cm = 25cm ± 4cm @ 0° & 28cm ± 4cm @ 60°
2000m [ 1248 m/s] = 0.65 x 31cm = 23cm ± 3cm @ 0° & 25cm ± 4cm @ 60°
3000m [ 1172 m/s] = 0.56 x 31cm = 20cm ± 3cm @ 0° & 22cm ± 3cm @ 60°


So the T-62/55 tanks and the lighter armor of most early model T-64/80 Russian tanks, can be dealt with @ 1-2km unless covered by ERA elmemets.

Not sure why the website has different name than JANES but they got the ammo figures wrong

Projectile weight.....................52 Kg (5.54 lb)

52kg????, even if its 5.2kg , that should be ~ 11.44 lb.

But NATO Triple heavy plate @ 57° is a different target, usually its @ 65°.

NATO Triple heavy targets Vs 21mm diameter APFSDS should be
x 10mm [ @ 412-438 kp/mm² ]+330 air +25mm [@ 100-122 kp/mm² ] +330 air +80mm, [@ 308-353 kp/mm² ] .

Thats 1cm SHS [ 1.2Te x 0.6 (t/d)] + 2.5cm Mild steel [0.8 Te x 0.88 (t/d)] + 8cm Heavy RHA [1.1 Te x 0.95 (t/d)] ...0.72+1.76 +8.36 = 10.84 @ 57°[/0.5446]= 19.9cm plus spaced plate effect. This should be an average of 1 rod diameter per spaced plate or + 41mm [ ~ 24cm]....

But with such a health air gap between plates the yaw of the attacking rod should be a factor. What little data I have suggests the yaw will be about ~ 1/COS² of the impact angle [57° ~ 0.5446 or 1/0.5446² = 3.4 times] .Since the average impact yaw 0.5 to 2° , this suggests 2-7° Yaw through the spaced plates. Given a 15:1 L/d thats a 'critical yaw' of ~2.3 or 1-3 times the Critical yaw, for a loss of 3-20% or additional 0.5-3 rod diameters. [Int.J.Impact Engng Vol-12 pp 281-292]


Thats about 24.5-30cm approximate resistance for the NATO triple heavy plate @ 57° or an average of 27± 3cm RHAe against that projectile.



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If a steel spaced plate is 0.2 t/d [5/8 inch = 2 inch] of a steel attacking AP type projectile, then this will decap the APC/APCBC projectile. This will end up offering 1.2 times the LOS resistance for the spaced plate arrangement, thus a 5/8 inch spaced plate and a 1.87 inch LOS thickness of plate should offer 2.25 inches of RHA resistance. If the threat is a WC core APDS/HVAP with a steel sheath this should offer ~ 1.5 times the LOS resistance while aluminum sheathed WC cores appear to result in 1.7-1.8 times the LOS resistance.

2 inch Steel APC = 1.2 x 1.87 inches or ~ 2.25 inches armor. [+ 0.2d] 1 x t/d .
2 inch Steel-WC HVAP/APDS = 1.5 x 1.87 = 2.8 inches armor. [ + 0.5d] 2 x t/d .
2 inch Aluminum-WC HVAP/APDS = 1.7-1.8 x 1.87 = 3.2- 3.4 inches armor. [+ 0.66-0.76 d] 3.3-4 x t/d.


1 inch Steel APC Vs t/d 0.625d [x 1] + 1.87 inches x 1.33 ~ 2.5 inches armor.[ + 0.6d = 1 x t/d]
1 inch Steel-WC HVAP/APDS Vs t/d 0.625 [2 x ] = 1.66 x 1.87 inches or ~ 3.1 inches armor.[+ 1.23d = 2 x t/d]
1 inch Aluminum-WC HVAP/APDS Vs t/d 0.625 [4 x] 2.35 x 1.87 inches or ~ 4.4 inches armor.[+ 2.0d = ~ 3.3 x t/d]

The above is interesting because the sharp tip of a ogive penetrator only appears to add 0.5d to the projectile L/d, so clearly the damage to the penetrator goes far beyond the disintegration of the tip.


Looking at modern APFSDS work , the spaced plate will offer a certain amount of rod shortning since its reported that at least one rod diameter is lost due to exiting the rear of each spaced plate. "When the target 'fails', that is there is perforation,the projectile no longer encounters and further resistance but projectile erosion continues some microseconds because of the large residual stresses in the plastic zone". [2001 Int Symp on Ballistic- TB-16].

In a test shot 16.5mm diameter 30:1 L/d WHA where fired at 1.8kms per second @ a spaced plate series of 6 x 19mm [340 BHN] RHA spaced plates infront of a witness plate. When the penetrator struck this arrangement it penetrated ~ 444mm of spaced plate and back up armor set back at an angle of 65°.

Had the penetrator struck a straight single block of 340 BHN RHA @ the same angle this should have generated a LOS penetration of ~ 533mm . Thus the difference [444-533 = 99mm/6= 16.5mm per plate], was an additional +1d [rod diameter] resistance for each spaced plate in the armor array.


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Light weight armor is being developed that can proof most AFVs against 7.62mm & 12.7mm AP shots that hardly adds much to the vehicles mass. The armor against 7.62mm would be 1/6 inch steel mass while armor mass needed to proof against 12.7mm is ~ ¼ inch steel mass. In the Int.J.Impact Engng Vol-19,pp 361-379 thin plates of aluminum and ABS sheets are sandwiched between ultra thin sheets of aluminm arranged perpedicular to the outer sandwich plates in a honey comb and wave pattern ‘flexcore’. This sandwich arrangement is shown to boost resistance 15-70% over the sum of resistance the individual elements show.


outer sheets
12.7mm vs 2x 1.5mm ABS 2x 0.8mm AL 2x 1.6mm AL
Flat 20m/s 50m/s 60 m/s
Conical 20m/s 50m/s 50m/s

6.35mm Vs 2x 1.5mm ABS 2x 0.8mm AL 2x 1.6mm AL
Flat 45m/s 60m/s 130 m/s
Conical 50m/s 65m/s 140m/s


While the insert 16mm insert offered

12.7mm Flexcore Honeycomb
Flat 15-20m/s 20- 30m/s
Conical 10-20m/s 30-40m/s
6.35mm Vs Flexcore Honeycomb
Flat 30m/s 20-30m/s
Conical 10-15m/s 10-15m/s


Thus the sum of the parts and the actual ballistic limit with the noted increase in effectiveness is below.
12.7mm conical AP shot vs 2 x 1.6mm AL & 16mm flexcore = 70-80m/s , when BL is 90m/s = + 20-30% density = 0.49g/cc
12.7mm conical AP shot vs 2 x 0.8mm AL & 16mm flexcore = 70-80m/s , when BL is 50m/s = - 30-40% density = 0.39g/cc
12.7mm conical AP shot vs 2 x 1.5mm ABS & 16mm flexcore = 35-40m/s , when BL is 39-41m/s = same density = 0.2g/cc


The sum of the parts and the actual ballistic limit with the noted increase in effectiveness is below.
12.7mm flat AP shot vs 2 x 1.6mm AL & 16mm flexcore = 75-80m/s , when BL is 119m/s = + 50-60% density = 0.49g/cc
12.7mm flat AP shot vs 2 x 0.8mm AL & 16mm flexcore = 65-70m/s , when BL is 62m/s = - 05-10% density = 0.39g/cc
12.7mm flat AP shot vs 2 x 1.5mm ABS & 16mm flexcore = 35-40m/s , when BL is 40m/s = same ; density = 0.2g/cc
A similar mass 3.8mm thick steel target should offer a BL of ~ 170m/s to a 12.7mm flat steel shot.


Thus the sum of the parts and the actual ballistic limit with the noted increase in effectiveness is below.
6.35mm conical AP shot vs 2 x 1.6mm AL & 16mm flexcore = 140-145m/s , when BL is 195m/s = + 35-40% density = 0.49g/cc
6.35mm conical AP shot vs 2 x 0.8mm AL & 16mm flexcore = 75-80m/s , when BL is 114m/s = + 40-50% density = 0.39g/cc
6.35mm conical AP shot vs 2 x 1.5mm ABS & 16mm flexcore = 60-65m/s , when BL is 67m/s = same density = 0.2g/cc


6.35mm flat AP shot vs 2 x 1.6mm AL & 16mm flexcore = 160m/s , when BL is 180m/s = + 12% density = 0.49g/cc
6.35mm flat AP shot vs 2 x 0.8mm AL & 16mm flexcore = 80m/s , when BL is 110m/s = + 37% density = 0.39g/cc
6.35mm flat AP shot vs 2 x 1.5mm ABS & 16mm flexcore = 75m/s , when BL is 68m/s = - 10% density = 0.2g/cc


So inorder to stop a 12.7mm Sharp AP at point blank range you would require > 11 times the 0.49 density thick array ~ 5.5g/cc or 21cm thick array or a 7mm steel mass. A similar penetration against RHA should result in armor of ~ 35mm , which gives the armor a mass efficiency of ~5 . [Te of 0.17]

To stop a 12.7mm flat head Shot , would require almost 9 times the thickness or 16cm thick array with a steel mass of 4.3g/cc or ~5mm steel mass.

So in order to stop a 6.35mm Sharp AP at point blank range you would require > 5 times the 0.49 density thick array ~ 2.6g/cc or 10cm thick array or a 3mm steel mass. A similar penetration against RHA should result in armor of ~15- 16mm , which gives the armor a mass efficiency of >5. [Te of ~ 0.16]

To stop a 6.35mm flat head Shot , would require almost 6 times the thickness or 11cm thick array with a steel mass of 2.8g/cc or ~4mm steel mass.


It seems the bigger the diameter of the shot the more efficient the armor becomes and it seems that from studies of the damage around the impact point the array displaces the impact energy along the flexcore members. Truth is this should also be a fairly mass effective armor against continuous jet shaped charges.In studies of shaped charge penetration of low density materials a density should result in the 21cm array offering ~13cm HEAT , while 16cm array should offer ~10cm HEAT resistance and a 10cm array should offer ~5cm HEAT protection against semi particulated jet.

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Explosive Reactive Armour (ERA)

The traditional flyer plate explosive filled ERA. Its main CE jet defeat mechanisms are jet erosion, jet deflection, and jet rotation (i.e. in the pitch and yaw axes, not the roll axis). Against KE rounds its performance varies depending on the number of plates. If it only has a front flyer plate and an immobile back-plate it defeats by deflection, rotation, and fracture of the rod. An X-ray shows a medium caliber rod broken 1/3 of the way along its length, and bent at a 20-30 degree angle around that point. However, if the ERA has front and rear flyer plates the defeat mechanisms also include erosion. X-rays of this configuration show the rod being reduced to an angled stream of crushed fragments on the far side of the rear flyer-plate.

Upside: Of all the types they describe they rate it as the "most effective proven technologies against CE and KE munitions". It's inexpensive, easy to make, and has good multi-hit capability in modular configurations.

Downside: It's full of explosive, which leads to user uneasiness, and high costs of storage, logistics, security, etc. It has a high weight burden if the vehicle needs reinforcement to handle the explosion.

Self-Limiting Explosive Reactive Armour (SLERA)

Apparently flyer-plate type armour, like ERA, but with less violent explosive material.

Upside: Comparable performance to ERA, but with less effect on vehicle, "extremely insensitive explosive material", good modular multi-hit configuration, inexpensive and easy to fabricate.

Downside: Still has explosive in it, with all its bad PR, and it's not as effective as fully detonable explosives. Considered unproven technology.

Non-Energetic Reactive Armour (NERA)

These are the plate-bulging armours. Defeat mechanisms are jet erosion, deflection, and rotation.

Upside: "Very effective against CE munitions", pasive, easy on vehicle structure, excellent multihit capability vs CE, easy modular integration, and inexpensive and easy to make.

Downside: "Configurations tested to date not effective vs. KE rounds", although they are trying to make them work against medium caliber KE. (i.e. autocannons)

Interestingly, they show a picture of an array set up for testing, composed of 6 double layered plates held apart by impromptu spacers. They label it "Khafji Armor".

Non-Explosive Reactive Armour (NxRA)

Apparently a slightly more violent version of plate-bulging NERA-type armours. Defeat mechanisms are, once again, jet erosion, deflection, and rotation.

Upside: "More effective than NERA vs. CE munitions", good multi-hit capability vs CE, easy modular integration, inexpensive and easy to fabricate.

Downside: Believed to be not effective vs KE rounds (implying they haven't checked yet, it seems).


I find it interesting that despite the desire to find safer, milder forms of reactive armour, the best performance is still given by the explosively driven versions. It seems that nothing substitutes for a fast, violent, massive interaction with the incoming threat.


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A bit confusing, but this is what I've got on MEXAS.]

Gah! This will take a while to work through!

Edit: Wait, I've read a lot of this before... Looking for new articles.

Interesting... only one or two are relevant to the MEXAS debate. As I see it, the spaced armour that they seem to think MEXAS uses degrades the penetration of the jet rather than increase the effective armour thickness... while this may seem the same, it's not. It means that the armour will be more effective against larger projectiles... but even with those large projectiles, enoiugh energy will get throiugh to do damage.

Aditionally, while the spaced armour they describe does seem to have high effectiveness at angles close to normal, I wonder how it will perform at the sloped angles usually uised in tanks... performence is actually DEGRADED as the LOS thickness of the armour plates is inreased, so angling it may in fact show no increase in effectiveness.

I also see nothing that suggests mexas has a Te greater than 150mm RHA... YOu also want the MEXAS in front of the Chobham style armour.... it's energetic armour, which means it changes shape. You don't want the hull of your tank changing shape... MEXAS is merely a kind of applique armour. Make the hull out of the Chobham style armour, put a layer of MEXAS on top, and the ERA on top of that.

Alright, thanks man! I really appreciate it!

And yes, the MEXAS alone would do poorly on an MBT, as not only can it be penetrated but it's effectiveness against KE is rather miniscule - however, it does give that extra armor needed just in case.

NP, working on a couple of armoured designs of my own, hope you'll return the favor =)

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