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Ilichs Eyebrows:Soviet BDD Tank Armor and Its Impact on the Battlefield

by James M. Warford

The practice of adding additional oradd-on armor protection to older tanksto increase their effectiveness andlengthen their service life has beenaround almost as long as tanks them-selves. Add-on materials ranged from amixture of quartz gravel, asphalt, andwood flour to more sophisticated non-explosive and explosive reactive armordesigns.

A classic example of successful add-on armor is the Soviet-developed BDDarmor. Nicknamed Brow armor be-cause of its resemblance to VladimirIlich Lenins thick eyebrows, BDDarmor has had a significant impactthroughout its service life, most re-cently in the fighting in Afghanistan.

In 1983, the Soviets initiated an up-grade program for the T-55 main battletank (MBT) intended to lengthen itsservice life. This rather extensive up-grade program included the addition ofthe new Volna fire control system witha laser rangefinder mounted externallyin an armored box above the tanks

100mm main gun, and a new, stabilizedprimary sight for the tank gunner. Theupgrade program also allowed the op-tional incorporation of the new 9K116Bastion gun-launched anti-tank guid-ed missile (which in NATO was knownas the AT-10 Stabber). The T-55s thatwere equipped with this missile capa-bility could be identified by the newand larger 1K13 turret roof-mountedgunners primary sight.

In addition to these significant fire-power improvements, the upgraded T-55s were also fitted with the new V-55U up-rated diesel engine that pro-

vided a power increase to 620 hp.These upgraded T-55s were known bya variety of designations depending onwhere they were produced: T-55M andT-55AM (Soviet/Russian produced); T-55AM2P (Polish produced); and T-55AM2B (Czechoslovakian produced).

While these and other less significantupgrades and modifications greatlyimproved the capabilities of the T-55,the most significant part of the upgradeprogram was the addition of the BDDor Brow add-on armor. The applica-

tion of the BDD armor involved theaddition of three external steel boxes;one large box on the glacis, and twosmaller curved boxes on the turret (oneon either side of the tanks main gun).The glacis box was made of steel plates30mm thick and covered most of theoriginal glacis. The box was filled withsolid polyurethane. Encased within thebeer-colored polyurethane were sixangled and evenly spaced 5mm thicksteel plates. These internal steel plateswere held in-place within the polyure-thane by what appear to be structuralbrackets.When viewed in profile, the BDD ar-

mor provides an impressive multi-layered array of alternating layers ofsteel and polyurethane. The BDD glacisbox was a total of 150mm thick. Thecurved turret boxes, on the other hand,each had an outer layer of 60mm thicksteel plates and include a larger numberof the internal 5mm plates encasedwithin the polyurethane. Additionally,these 5mm plates are apparently verti-cal (not angled like those used in theglacis box) and are configured in such away to ensure an attacking projectile

would be forced to penetrate several ofthe alternating layers before reachingthe turret base armor. The complete ap-plication of BDD armor adds about 2metric tons to the weight of the tank.BDD armor is classified as non-ener-

getic reactive armor (NERA) since thereaction it produces (the defeat mecha-nism) is not caused by an explosivematerial, but by the impact of an attack-ing projectile on the polyurethane ineach box. This reaction can have a hugeimpact on an attacking projectile or themolten jet from a shaped-charge war-head. When the projectile strikes andpenetrates the outer layer of the BDDsteel box, it sends an intense shockwave into the polyurethane, whichcompresses within the steel box. Sincethe compressed polyurethane (and theenergy transferred to it from the projec-tile impact) has nowhere to go due toits confinement in the steel box, it isforced to move back into the path of theprojectile. The effect is like compress-ing a powerful spring and suddenlyreleasing it towards the projectile.While the cause and effect of this reac-tion within the BDD box is well under-

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The T-55 upgrade includes additional armor, a laser rangefinder above the main gun,a new fire control system, and an improved gunners primary sight.

- Jody Harmon drawing

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stood, the role played by the 5mm steelplates and the structural brackets hold-ing them in place is not as clear-cut.While some sources report that the5mm plates are in-fact bulging plates(designed to be set in motion by thereaction of the polyurethane to actuallyattack the projectile), a more likelyexplanation is that the 5mm plates andthe structural brackets are intended tofurther confine the polyurethane in eachBDD box. By increasing the surfacearea beyond that provided by the boxitself, the additional confinement of thepolyurethane (between and around the5mm steel plates) equates to a largerreaction working against the attackingprojectile.

In recent years, NII Stali (Russiasprimary tank armor research and de-velopment organization), has becomemuch more forthcoming with informa-tion regarding its armor developments.In a product pamphlet called Sugges-tions on Modernization of MBTs andIFVs distributed at a recent arms exhi-bition, NII Stali provided a few impor-

tant details concerning BDD armor. Ina section called Armor Protection Up-grading Variant 1, BDD armor (de-scribed as metal-polymer block), iscredited with adding 120mm of protec-tion against APDS and 200-250mm ofprotection against HEAT or shaped-charge ammunition. In effect, the 60-degree frontal arc of a T-55 fitted withBDD armor was suddenly immune totank-fired 105mm APDS and HEAT, aswell as Rocket Propelled Grenade(RPG) ammunition. This new informa-tion confirms that this additional capa-bility was a huge step forward at thetime, and easily extended the servicelife of these upgraded T-55s for severalyears. In addition to the upgraded T-55s, BDD armor was also added toupgraded T-62 MBTs starting in 1983.These upgraded T-62s were designatedT-62M and T-62M1. A number of theseT-62Ms were recently used in combatin Chechnya. Finally, a few years ago,a surprising single photo was publishedof a T-72 MBT fitted with BDD armor.Virtually nothing is known about thisparticular T-72 or where the photo was

taken. It could have been part of atest project or it may have been(based on the terrain in the photo)one of the small number of T-72sthat were reportedly deployed to

Afghanistan during the Soviet-Afghan War. Interestingly enough,no confirmed photos of thoseSoviet T-72s have ever been pub-lished.

The value and impact offered byBDD add-on armor have onceagain made themselves known;this time, by the deployment ofupgraded T-55AMs in Afghani-stan. As part of a $45 millionweapons transfer package fromRussia, the Afghan United Front

(also known as the Northern Alliance)was supplied with 40 T-55AM2 MBTs.These tanks offer a variety of advan-tages to the forces of the United Front.In addition to being simple, reliable,and well understood (ideally suited forAfghan tank crews), the new T-55AM2s include capabilities beyondthose of tanks previously used in Af-ghanistan. In a manner reminiscent ofthe Cold War years, the BDD armorprotecting these T-55AM2s providescomplete frontal protection against keyopposing anti-tank weapons. In Af-ghanistan, the weapon at the top of thislist is certainly the ubiquitous RPG.Whether deployed in Afghanistan in2001 or serving with the Soviet andWarsaw Pact forces during the ColdWar years, BDD add-on armor hasbeen an unqualified success. Perhapsthe most important thing to keep in-mind when evaluating the success ofBDD armor is to remember that it wasnot developed in a vacuum. The rela-tionship between it and other more re-cently developed Soviet/Russian add-on and composite tank armors is still tobe determined.

James M. Warford was commis-sioned in Armor in 1979 as a Dis-tinguished Military Graduate fromthe University of Santa Clara, SantaClara, California. A frequent con-tributor to ARMOR , Mr. Warford hasheld a variety of Armor and Cavalryassignments, ranging from tankplatoon leader to brigade S3, andhas served as a tactics instructorboth at Fort Knox, Ky. for AOACand at Fort Leavenworth, Kan. forCGSC. He is currently a trainingdeveloper in the Kansas City area.

At left, Russian T-62s with the added turret armor areseen on a road in Chechnya. The close-up aboveshows the added armor on one side of a Czech T-55AM2B turret. Also seen on the turret roof is the largergunners primary sight doghouse that can control theAT-10 Stabber guided missiles.

Close-up of 5mm steel plates embedded inpolyurethane blocks, a form of non-explosivereactive armor, added to the glacis.

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