Slat armor

Slat armor (or slat armour in British English), also known as bar armor, cage armor, and standoff armor, is a type of vehicle armor designed to protect against high-explosive anti-tank (HEAT) attacks, as used by anti-tank guided missiles (ATGMs) and rocket-propelled grenades (RPGs).

An IDF Caterpillar D9 armored bulldozer equipped with slat armor surrounding its driver's cab

Operation

Slat armor takes the form of a rigid slatted metal grid fitted around key sections of the vehicle, which disrupts the shaped charge of the warhead by either crushing it, preventing optimal detonation from occurring, or by damaging the fuzing mechanism, preventing detonation outright. Although slat armor is effective against incoming missiles, it does not offer complete protection – as many as 50% of missile impacts are unimpeded by the slat design.^[1] Slat armor is more likely to be effective if the cage spacing is less than the diameter of the incoming RPG round, which is commonly 85 mm.^[2]

Combat history

World War II

 

Panzer IV Ausf. H on display (with slat armor) at the Musée des Blindés in Saumur

The German Wehrmacht was the first employer of cage armor during World War II, using Drahtgeflecht-Schürzen (English: "wire mesh skirts") to fortify its tanks against shell fire.^[3] It was found to be just as effective as the steel plate Schürzen also being utilized. In March 1943, Adolf Hitler ordered all new Sturmgeschütz, Panzer III, IV, and Panthers be outfitted with Schürzen of either the wire mesh or steel plate type. However, the wire mesh was not as easy to mass-produce as steel plate Schürzen or armored skirts. Soviet Red Army tanks, faced with the new and highly effective German Panzerfaust, were similarly outfitted with "bedspring" armor made from expanded metal mesh grating panels.

However, Schürzen were designed to stop Soviet PTRD-41 anti-tank rifles, and proved ineffective against Bazooka and Panzerschreck anti-tank rockets in US and German tests.^[4]

Cold War era

 

A 1960s Stridsvagn 103C tank at the Swedish Army Museum, Stockholm, with anti-high-explosive anti-tank (HEAT) fence armor on the front

In the Vietnam War, slat armor was commonly used on the sides of American patrol barges and boats. The CCB-18 is a surviving example of the Mobile Riverine Force which used such armor.^[5] Wire fencing was also placed on vehicles such as the M113 to defeat Vietcong RPGs. The Swedish Stridsvagn 103 of the same era employed a much heavier front-mounted metal grid to protect against incoming projectiles.

Modern era

In modern times, slat armor has seen use on the Israel Defense Forces (IDF) Caterpillar D9R armored bulldozer, the Force Protection Buffalo MPV MRAP vehicle, the General Dynamics Stryker, Ukrainian BTR-4, the Warrior infantry fighting vehicle,^[6] the M113 APC, the British Challenger 2, the Leopard 2A6 main battle tank,^[7] and Russian T-62 tanks.^[8] Slat armor is favored over traditional plate armor not only due to its effectiveness against shaped-charge warheads, but also due to its much lighter weight, which improves vehicle maneuverability.^[9]

Slat armor was first used on the Israeli IDF Caterpillar D9R armored bulldozer in 2005, and was installed in large numbers in 2006. Around the same time in 2005, slat armor was first proposed for the Stryker by a team of experts from the Army Research Laboratory (ARL), the Developmental Test Command, and the Aberdeen Test Center (ATC) to protect the vehicle from RPGs.^[10] Within seven days, the ARL and ATC designed and produced the first prototype, which was later mass produced at the Lima Army Tank Plant in Ohio and implemented in different variants of the Stryker. The design of the slat armor has the cage placed 50 cm ahead around the vehicle, allowing an RPG warhead to explode at a safe distance.^[2] Also, the slat armor on the Stryker vehicles is reportedly effective against HEAT rounds.

In 2007, BAE Systems developed a very lightweight aluminum slat armor system named LROD, which was initially used on the Buffalo MPV, and which was claimed to weigh half the amount of comparable steel designs.^[6] BAE later equipped several US Army RG-31s with a variant of the LROD system, and also developed the system for its RG-33 vehicles, the Caiman and the JERRV. Slat armor is also fielded on the American M1 Abrams as part of the Tank Urban Survival Kit (TUSK) urban warfare series. In the Syrian Civil War, Islamic State of Iraq and the Levant (ISIS), the Free Syrian Army and Syrian Army equipped their armored vehicles with homemade slat armor to protect them from RPG impact.

In August 2016, Russia introduced bar-slat armor developed by NII Stali and Uralvagonzavod to increase protection of Russian armored vehicles against RPG and recoilless rifle HEAT rounds by 55-60%. The armor can be integrated with a variety of old-Soviet and Russian vehicles including the BTR-50, BTR-60, BTR-70, BTR-80/82, BTR-90, BMP-1, BMP-2, BMP-3, BRDM-2, BRDM-3, and T-14 Armata, with the full kit adding 1,000 kg (2,200 lb) of weight.^[11]

Top-mounting

 

An abandoned and damaged Russian T-72B3M tank with improvised top-mounted slat armor during the 2022 Russian invasion of Ukraine at Mariupol

In 2021, various Russian tanks were observed with top-mounted improvised slat armor made from steel grilles;^[12] these were nicknamed kozyrek ot solntsa (Russian: козырек от солнца, lit. "sun visors") by Russian tank crews,^[13][14] and the Russian Ministry of Defense stated in mid-2021 that they were intended to enhance protection against "various weapons".^[14] In December 2021, the Ukrainian Army released video of a military exercise in which an armored fighting vehicle (apparently a BTR fitted with a T-64-like turret) carrying such equipment was destroyed by a Javelin missile.^[15] These implementations add weight to the tank, increase its visual profile, and make it more difficult for the crew to enter and exit the vehicle.^[16] In 2022, during the Russian invasion of Ukraine where they saw combat usage, they were pejoratively termed "cope cages"^[17] by English-language online communities, western military analysts, and British defence secretary, Ben Wallace,^[18] expressing scepticism over their real-world effectiveness, based on the assumption by these analysts that the armor was most likely designed in an attempt to mitigate the threat of top-down anti-tank missiles such as the FGM-148 Javelin, and other top-attack munitions.^[19]

Other analysts have proposed that they may instead be used as a countermeasure against HEAT warheads from weapons such as RPG-7s fired from above during urban combat, loitering munitions, or against drone attacks, as a response to lessons learned from the 2020 Nagorno-Karabakh war^[20] and First Chechen War.^[21] The lack of uniformity between the makeshift cage variants made from different meshes and iron fences suggest that they are largely improvised by the tank crews, and are not standard issue.^[22][23] In May 2022, it was reported in Russian media interviews with Russian tankers who have returned from Ukraine that their crews eventually removed the cages, as they obstructed the use of machine guns and radios, and prevented timely evacuation if the tank caught fire.^[24]

Gallery

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  Slat armor on an upgraded M113 armored personnel carrier in 2008

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  Slat armor protecting the engine exhaust port at the rear of the hull of an M1 Abrams

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  Lighter netting type fitted to a Polish KTO Rosomak in Afghanistan, 2010

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  Slat armor on a BvS 10 Viking ATV in 2012

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  Slat armor of an IDF Caterpillar D9 armored bulldozer

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  Slat armor protecting the rear of the turret of a Type 59G Durjoy tank

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  Buffalo vehicle with attached slat armor in Afghanistan

See also

• Reactive armour
• Spaced armour
• V-hull
• Vehicle armour

References

1. "BAE’s LROD Cage Armor". Defense Industry Daily. 17 August 2012. Retrieved 13 February 2015.
2. Yap, Chun (September 2012). . Naval Postgraduate School. Archived from the original on June 11, 2017 – via Defense Technical Information Center.
3. "Sturmgeschütze vor!"StugIII.com. Retrieved 12 February 2013. 8 December 2013 at the Wayback Machine
4. Bazooka vs Panzer, Battle of the Bulge 1944, Steven J. Zaloga, Osprey, p. 34, 38
5. CCB Memorial Fund 2014-10-06 at the Wayback Machine. MRFA.org. Retrieved 12 February 2013.
6. "The MRAP Cage Fight". DefenseTech.org. 18 July 2007. Retrieved 4 October 2012.
7. "Background — CF Leased & Purchased Leopard 2 A6M / 2 A4 Tanks" 2008-04-16 at the Wayback Machine. CASR. Retrieved 12 February 2013.
8. "A Russian serviceman reads next to a T-62 tank in Gori near South Ossetia, August 15, 2008". Reuters via Flickr. Retrieved 1 April 2012.
9. "Slat Armour for Stryker". Defense-Update.com. 2005. Retrieved 12 February 2013.
10. Rooney, John (January 2007). . ITEA Journal: 4–6. Archived from the original on March 10, 2021 – via Defense Technical Information Center.
11. Russia develops bar-slat armour to protect combat vehicles - Armyrecognition.com, 19 August 2016
12. Roblin, Sebastien. . Forbes. Archived from the original on 2022-03-11. Retrieved 2022-03-11.
13. "Противоракетный "козырек": Т-72Б3 с новой защитой замечен под Ростовом". Rossiyskaya Gazeta (in Russian). June 18, 2021. from the original on June 18, 2021. Новое защитное устройство, установленное в верхней части башни, внешне напоминает навес, за что получило среди танкистов неофициальное название - "козырек от солнца". [The new protective device, installed on the upper portion of the turret, appears similar to a canopy, earning it the unofficial name "sun visor" among tankers.]
14. "На российские танки начали устанавливать импровизированную защиту от Javelin и БПЛА". Новости ВПК (in Russian). July 7, 2021. Archived from the original on April 5, 2022. Защитное устройство в верхней части башни получило неофициальное прозвище «козырек от солнца». В Минобороны сообщили, что оно предназначено для усиления защиты от разных средств поражения... В военном ведомстве не рассказали о принципе действия защиты, однако отметили, что другие Т-72 тоже получат «козырек». [The protective device at the top of the turret was given the informal nickname "sun visor". The Ministry of Defense reported that it is intended to enhance protection against various weapons... the military department did not talk about the specifics of the protection, but noted that other T-72s would also have the "visor" installed.]
15. Thomas Newdick (23 December 2021). "Ukrainian Troops Test Javelin Missile Against Russian Cage-Style Improvised Tank Armor". The Drive. Brookline Media Inc.
16. Alia Shoaib (March 26, 2022). "Russian soldiers appear to be fixing makeshift cages to the turrets of their tanks in a crude effort to protect themselves against Ukraine's anti-tank missiles". Business Insider. from the original on March 26, 2022. "The advantage Russian tanks have is that they're super small and very low, making them easy to hide. When you start doubling the height, you're getting rid of some of the advantages of the vehicle," Crump said. The cages also make it harder for the crew to get in and out of the vehicles, according to Crump.
17. "Russian tanks in Ukraine are sprouting cages". The Economist. March 14, 2022. from the original on March 16, 2022. They have indeed been mockingly dubbed by Western analysts as 'emotional support armour' or 'cope cages'. Superficially, they are an example of what is known in military circles as field-expedient armour—in other words, stuff that has been added to vehicles after they have entered service.
    "Igazi tankszörnyet zsákmányoltak az ukránok". Portfolio.hu (in Hungarian). March 2, 2022. Archived from the original on March 15, 2022. Érdekes egy szót említeni a „kutyaólként" vagy "csirkeketrecként," angolszász forrásokban „cope cage," vagyis durván „dolgozd fel ketrecként" emlegetett improvizált páncélzatról a tornyon. A páncélzat célja az lenne, hogy megvédje a harcjárműveket a felülről érkező drónrakétáktól vagy páncéltörő rakétáktól. [It is interesting to mention the terminology surrounding the improvised armour on the tower, referred to as 'dog kennel' or 'chicken coop' in Hungarian, or 'cope cage' in Anglo-Saxon sources. The purpose of the armor would be to protect the combat vehicles from drone missiles or armor-piercing rockets coming from above.]
    James Dwyer (March 10, 2022). "How do anti-tank missiles work, and how helpful might they be for Ukraine's soldiers?". Australian Broadcasting Corporation. from the original on March 15, 2022. These are colloquially termed 'cope cages' by various communities on the internet. Of course, they will do little to minimise the impact from a missile, but they do demonstrate that Russian soldiers are fearful of the threat the missiles present.
    "What to know about the role Javelin antitank missiles could play in Ukraine's fight against Russia". Washington Post. March 12, 2022. Archived from the original on March 12, 2022. Social media has been littered with photos of destroyed Russian tanks with cages. The images have acquired a symbolic resonance so quickly that Internet users have coined the term 'cope cage' earning a page on the Internet's primary meme directory.

18. "Speech by Defence Secretary on Russia's invasion of Ukraine". gov.uk. 9 May 2022. from the original on May 9, 2022. Retrieved 2022-05-09. Russian soldiers' futile use of pine logs as makeshift protection on logistical trucks and attaching overhead 'cope cages' to their tanks, it's nothing short of tragic. But their commanders' failures to adapt before entering them into such a conflict is criminal.
19. "Russian tanks in Ukraine are sprouting cages". The Economist. March 14, 2022. from the original on March 16, 2022. They appear to be oriented in a way that protects only against attacks from above. In principle, that might help against Javelins, which have a 'top attack' mode ... [but] even if the cage sets off a Javelin's precursor warhead, the main charge is still more than powerful enough to punch through the top armour and destroy the tank
    Alia Shoaib (March 26, 2022). "Russian soldiers appear to be fixing makeshift cages to the turrets of their tanks in a crude effort to protect themselves against Ukraine's anti-tank missiles". Business Insider. from the original on March 26, 2022. "The cages are supposed to defend against anti-tank weapons that strike the top of the vehicle, where the armor is the thinnest. "The idea is that if you set off a bazooka or a Panzerfaust... they're set off early and so they don't hit the tank itself..." Crump explained. However, the cages are largely ineffective against the modern anti-tank weapons used by the Ukrainians, such as the Javelin and NLAW... Many modern weapons are designed to counter that sort of protection

20. "Russian tanks in Ukraine are sprouting cages". The Economist. March 14, 2022. from the original on March 16, 2022. Another idea is that the cages are a response to the conflict in 2020 between Armenia and Azerbaijan, over Nagorno-Karabakh, in which large numbers of Russian-made Armenian tanks were destroyed from above by MAM-Ls ... A third possibility is that the cages are meant as protection against RPGs ... which are being fired at tanks from above. This ... is a preferred tactic in urban warfare, where buildings offer shooters the necessary elevation.
    "Les «cope cages», protections bricolées et moquées des chars russes impuissants". Slate.fr (in French). March 23, 2022. from the original on March 23, 2022. Ces structures approximatives sont ce qu'il est devenu coutumier d'appeler des cope cages en anglais –des «cages pour faire avec», pour traduire grossièrement l'expression. Elles sont le résultat des observations par l'armée russe du conflit opposant Azerbaïdjan et Arménie dans le Haut-Karabakh. [It has become customary to call these makeshift structures "cope cages" in English, an expression which roughly translates to "cages pour faire avec". They are the result of observations made by the Russian army towards the conflict between Azerbaijan and Armenia in Nagorno-Karabakh.]
    Newdick, Thomas (24 November 2021). . The Drive. Archived from the original on 24 February 2022. Retrieved 2022-03-11.

21. Robert Tollast (April 7, 2022). "How Javelin missiles penetrate Russian tank cage armour". The National. from the original on April 8, 2022. ...the Russians might have had another defence in mind, possibly drones with small missile warheads attacking from above, or RPGs being fired from rooftops in urban battles, a problem Russia encountered in Chechnya.
22. Alia Shoaib (March 26, 2022). "Russian soldiers appear to be fixing makeshift cages to the turrets of their tanks in a crude effort to protect themselves against Ukraine's anti-tank missiles". Business Insider. from the original on March 26, 2022. The lack of uniformity of the cages, and the fact that they are only seen on some tanks, shows that Russian units are largely improvising them
23. Robert Tollast (April 7, 2022). "How Javelin missiles penetrate Russian tank cage armour". The National. from the original on April 8, 2022. ...even in cases where the slat armour could be useful, perhaps against small "kamikaze drones" or small munitions fired or dropped from drones, the DIY nature of the Russian cages could still be a fatal flaw. Quality engineering "does not apply to the 'cope cage'... The 'grill' appears to be less dense than proper cage armour and constructed from random household materials in some cases."
24. Sergei Valchenko (May 24, 2022). "Танкист-герой рассказал о спецоперации и погиб: «Победим, но легко не будет»". Moskovskij Komsomolets (in Russian). from the original on May 24, 2022. Обвесы (металлические решетки для защиты от противотанковых ракет) мы сначала все наварили на танки, а потом их все сняли. Во-первых, неудобно: пулемет не двигается, антенна когда замыкает об решетку – сгорает радиостанция, связь пропадает. И если будет какое-то возгорание, там просто нереально будет вылезти из танка... Поэтому их все сняли и выкинули. [At first we welded the body kits (metal grilles for protection against anti-tank missiles) to the tanks, but then they were all removed. Firstly, it is inconvenient: the machine gun is unable to move, and the radio connection disappears when the antenna touches the grille. If there is some kind of fire, it will be simply unrealistic to get out of the tank... So they were all removed and thrown away.]

External links

•   Media related to Slat armor at Wikimedia Commons