T-72B(M)/T-90 Armor Estimate

Preliminary notes:

Steve Zaloga's new book¹ suggests the T-72B MBT has BDD-type armor in the turret along the lines of T-55M and T-62M MBTs. T-72B(M) and T-90 turret reportedly have BDD type armor as well. The array has 380mm cast steel and 435mm insert, but the composition is probably improved. The probable upgrade path is the replacing of Aluminum bulging plates with Titanium. Building on the figures for previous BDD equipped tanks we get

		TE vs KE	TE vs HEAT
T-72B	Aluminum/rubber sandwhiched between cast steel	0.41	0.34
T-72B(M)/T-90	Titanium/rubber sandwhiched between cast steel + air gap	0.56	0.79

T-90 turret projection without Kontakt-5 could thus be 38cm x 0.9₂ + 43.5cm x 0.56 = 59cm KE (the free edge effect will reduce this further to 0.95 x 59cm or 56cm KE) and 38cm + 43.5cm x 0.79 = 72cm HEAT.

Kontakt-5 coverage seems to be about 50%.

Upper front turret is 5cm cast plus 5cm STEF at ~77-78°.

Glacis is 235mm thick with probably 105mm STEF and 30mm hard steel. The TE of STEF is 0.41 KE and 0.55 HEAT and the TE of hard steel is 1.34 vs KE & 1.3 vs HEAT. Thus the glacis should offer [3 x 1.34 + 10.5 x 0.41 + 11] / 0.38 =~51cm KE and [3 x 1.3 + 10.5 x 0.55 + 11] / 0.38= ~ 54cm HEAT armor. With Kontakt-5 the KE value is up 15-20cm KE and 40-50cm HEAT thus about 69±2cm KE and ~99±4cm HEAT.

Lower hull is 8-10cm at 64° = LOS thickness of 0.438 or 17-23cm KE and HEAT armor.

Now to the figures.

Front armor diagram

	~80-90cm LOS cast mantle x 0.6-0.7¹ = 54-56cm KE & 80-90cm HEAT
	81.5cm LOS x 0.72 [Cast/Ti-BDD] = 59cm x ~0.95₃ = 56cm plus K-5 = 74±2cm KE 81.5cm LOS x 0.88 [Cast/Ti-BDD] = 72cm plus K-5 = 118±4cm HEAT
	70-72cm LOS x 0.72 [Cast/Ti-BDD] = 50-52cm x 0.99₃ = 49-51cm plus K-5 = ~67-69±2cm KE⁴ 70-72cm LOS x 0.88 [Cast/Ti-BDD] = 61-63cm plus K-5 = 104±5cm HEAT⁴
	44-48cm LOS x 0.66 [Steel/STB] = 29-32cm KE plus K-5 where present = 48±6cm KE 44-48cm LOS x 0.77 [Steel/STB] = 34-37cm HEAT plus K-5 where present = 70±16cm HEAT
	[3 x 1.34 + 10.5 x 0.41 + 11] / 0.38₅ = ~51cm KE plus K-5 = 69±2cm KE [3 x 1.3 + 10.5 x 0.55 + 11] / 0.38₅ = ~54cm HEAT plus K-5 = 94±4cm HEAT
	17-23cm KE and 17-23cm HEAT
	Side turret ranges from 40-60cm thick near front thinning to ~ 15-20cm around back. This is probably half and half cast/STEF thus the KE armor is 0.66 while the HEAT armor is 0.77. The effective KE armor ranges from 40cm narrowing quickly to 26cm and 10-13cm around back. The HEAT armor ranges from 46-31cm near the front down to 15-12cm Around back. In the side and rear turret are mounted external storage boxes ~50cm thick that will offer a modicum of spaced armor, this may amount to an additonal ~13-15cm HEAT armor. Additionally K-5 is mounted around the front side of the turret.
	The side hull is 6cm thick rolled steel but the lower side hull around the wheels is probably only 2cm thick; side skirts add 25 mm thick reinforced rubber [with steel?] plate plus 60cm airgap increasing the HEAT armor by about 15-17cm against 2nd gen and 26-28cm against 1st gen warheads. This rubber skirting is unlikely to add more than 1cm to the KE side armor, due to deflection. The fuel tanks along the sponsons should add 65cm x 0.1 KE and 0.3 HEAT or an additional 6-7cm KE and ~ 20cm HEAT armor. Over the front half of the side hull Kontakt-5 is mounted which probably adds ~30cm HEAT and at least 5 cm KE resistance.
	The rear armor is unlikely to be more than 4cm but fuel tanks mounted there could offer 0.1 to 0.15 Te resistance to APFSDS and 0.34 resistance to HEAT. The HEAT armor would range from 3-4cm to as much as 18cm additional HEAT armor.

¹ -	"Soviet/Russian Armor and Artillery design practices"
² -	adjustment of cast armor to RHA
³ -	adjustment for free-edge effect
⁴ -	a substantial portion of this projection on the right side of T-72B(M) is not covered by ERA due to mounting of L-4 IR searchlight; an area both on the left and right is not covered on T-90 because of Shtora emitters. In these areas, instead of K-5 assume additional <1cm KE and ~5cm HEAT protection.
⁵ -	adjustment for LOS due to angle