The Chieftain's armor was still strong against the T-55's guns, but the 115mm and 125mm smoothbore guns easily penetrated it.

We continue to publish reports from Soviet testers on the British tank A Chieftain Mk5P captured during the Iran-Iraq War. This time, we present a study of this vehicle's armor protection, which not only provides raw armor thickness figures, but also its penetration by Soviet guns of tanks such as the T-55, T-62, and T-72.

Armor protection

The Chieftain tank's design follows the British concept of 1944, which prioritized armor and firepower. The Chieftain tank follows a classic tank layout. In terms of the geometric layout of its hull and turret, as well as the design of several chassis components, the Chieftain shares similarities with the first-generation post-war Centurion tank.

The hull and turret armor utilizes the same grades of steel armor previously used for the Centurion tank's hull and turret. Both tanks are large (especially in hull length) and heavy. The Chieftain Mk5P weighs 54,8 tons.

The mass of the armored hull and turret is 29 tons, which is 53% of the mass of the entire vehicle.

Let's consider the geometric scheme of the hull and turret armor (figure).

The hull is welded using homogeneous cast and rolled armor of medium hardness. The cast upper glacis plate has a complex, streamlined geometric shape. It includes the driver's hatch opening, the front portion of the turret platform, and the turret ring guard.

The lower glacis plate is made of 76 mm thick rolled armor with a 45° slope. The main hull sides are made of 38 mm thick rolled armor with a 10° slope.

Geometric diagram of the armor protection of the Chieftain Mk5P tank

In the rear, above the track shelves in the engine-transmission compartment, are compartments housing rubber-fabric fuel tanks. The compartment walls are made of 19 mm thick rolled armor steel.

The rear of the hull is constructed from 25,4 mm thick rolled armor; the rear plate is positioned vertically. The hull bottom is constructed from 15,7 mm thick flat plates along its entire length, inclined at a 5° angle relative to the longitudinal axis of the hull. A 10° slope on the lower side increases the survivability of the welded joint between the bottom and the side from the shock wave generated by an anti-tank mine explosion by removing the weld from the track.

Along the entire length of the hull, on both sides of the tank, 800 mm from the main side, are four sections of 10 mm thick aluminum alloy armor. Each section is attached to the bottom via a bracket. The first section is box-shaped, and the remaining three are T-shaped. The bases of the brackets are welded to the chassis suspension housings.

A unique design feature is the replaceable brackets, as they are bolted to a base welded to the suspension housings. The aluminum screens are bolted to the sides at the top and pinned to the brackets at the bottom.

The idler mounting method is worth mentioning. The idler bracket and tensioning mechanism are bolted to a milled projection on the lower glacis plate, reinforced by two gussets welded to the main side. This mounting design allows for quick replacement of the idler and road wheels with elastic elements if damaged. The turret base is made of cast homogeneous armor of medium hardness.

It consists of a frontal section, side sections in the fighting compartment area and a front roof section.

The turret's rear and roof are made of rolled armor. The horizontal portion of the 25,4 mm thick roof contains hatches.

The turret rear is made of 35mm thick rolled armor. The turret design features:

- a narrow embrasure with a width of 255 mm, which allows the gun to be armored;

— mounting of the gun (carriage) in a lug protruding from the frontal part of the turret, which significantly reduces the weakened area of ​​the frontal projection of the turret;

— the presence of armored compartments located behind the main armor of the fighting compartment in the rear of the turret, in which additional equipment is located.

The following design solutions for the hull and turret elements are of interest in the tank under consideration:

— creation of armored fuel compartments in the hull;

— the use of a detachable mounting of the guide wheel brackets with the track tensioning mechanism on the body;

— creation of additional armored compartments in the rear part of the turret, located behind the main armor, for special equipment.

Analyzing the tank's armor diagram (see figure), along with the data (table) on the hull and turret's projectile resistance (calculated at the conditioned damage limit), we can conclude that the Chieftain's hull and turret lack anti-HEAT protection, as the horizontal armor thicknesses do not exceed 250 mm. However, it should be noted that the hull's lower side is equipped with a four-section aluminum armor plate, 10 mm thick.

The presence of such screens, taking into account the shielding action of the chassis components (rollers and suspension housings), ensures protection of the lower side from cumulative close-combat weapons within course angles of ±25–30°.

The armor of the upper frontal part of the hull and the frontal part of the turret provides protection:

— from 100-mm caliber and armor-piercing sub-caliber shells of the T-55 tank at a range of 500 m;

— from 115-mm armor-piercing sub-caliber shells of the T-62 tank at a range of 1600 m.

125mm armor-piercing sub-caliber projectiles offer no protection at actual combat range. The tank can be penetrated by these projectiles from a distance of over 3000 meters. The remaining portions of the hull and turret have low projectile resistance.

The rear of the hull and turret are protected against bullets and fragments. Welded joints between the hull and turret components are machined and feature small weld legs without continuous penetration.

This design of welded joints has low survivability when fired at by armor-piercing sub-caliber and high-explosive fragmentation projectiles, but is easy to assemble and does not require large labor costs during welding.

Conclusions

The turret and frontal projection of the hull of the Chieftain Mk5P tank do not have anti-cumulative protection.

The frontal projection of the turret and hull of the Chieftain Mk5P tank at real combat ranges is protected from 100 and 115 mm APFSDS and is damaged by 125 mm APFSDS.

Source:
"Armor Protection." O. M. Lazebnik, B. F. Makhov, A. F. Misyuk, E. V. Mikhailov. "Questions of Defense Technology", issue No. 5 (111), 1983.

Comments

[andrewkor]

But it would be desirable to know examples of real defeats of Chieftains during the Iran-Iraq conflict.

[AdAstra]

Were those tanks there?

[hohol95]

Shah Pahlavi purchased the Chieftains from the British and the F-14s from the Americans.
Then the Iranians and Iraqis purchased Type-59/Type-69 tanks from China.

[1944-1989]

During the wars of 1980–1991 (primarily the Iran–Iraq War and the invasion of Kuwait), hundreds of Chieftain tanks were destroyed. Many were abandoned or captured by the enemy due to engine problems.
The exact data for individual conflicts is as follows:
Iran–Iraq War (1980–1988): Iran entered the conflict with 894 Chieftain tanks. By the end of the war, only about 200 survived. Many were destroyed in direct combat with Iraqi T-62 and T-72 tanks, but a significant number were disabled by engine failure and a shortage of spare parts caused by the embargo. In the Battle of Dezful (January 1981) alone, the Iranian side lost 214 Chieftain tanks.
Invasion of Kuwait (1990): Kuwait deployed the 35th Armored Brigade, equipped with Chieftain tanks. During the so-called "Battle of the Bridges," Iraqi divisions engaged Kuwaiti armored vehicles. A total of 136 vehicles were destroyed or lost during the fighting (some of which fell into enemy hands). Only seven Kuwaiti Chieftain tanks survived the war.

[AdAstra]

Aaaaah, I see. "" "" "

[Jager]

I wonder what the Aberdeen Proving Ground specialists wrote in their reports about the captured T-90M?

[Quzmi4]

I wonder what the Aberdeen Proving Ground specialists wrote in their reports about the captured T-90M?

They're still writing

[belost79]

"...what they wrote in their reports..."
"The tank is a typical example of backward Bolshevik industry and cannot compete with machines designed and built by the best sons of the Reich."

[dragon772]

In the Tundra, it's cardboard. The turret front is 280mm thick, and the upper glacis is only 86mm, even a T-55 can penetrate it.

[Roman Efremov]

If the VLD has a slope greater than 70 degrees, multiply the thickness by 3.

[dragon772]

I know that Tundra sometimes calculates penetration incorrectly.

[hohol95]

— from 115-mm armor-piercing sub-caliber shells of the T-62 tank at a range of 1600 m.
...
The frontal projection of the turret and hull of the Chieftain Mk5P tank at real combat ranges is protected from 100 and 115 mm APFSDS and is damaged by 125 mm APFSDS.

1600 meters was considered a realistic combat distance in what terrain?
Desert, steppe, tundra, and so on?

[Roman Efremov]

The armor is laughable for such a heavy tank; only the upper glacis plate and the frontal sides of the turret are seriously protected. Later modifications apparently had an additional screen installed on the turret and upper glacis plate—it's clearly visible in the photo.

[MSN]

This isn't funny at all; it's a principle adopted after World War II—differentiated armor. For example, the Tiger has 100mm of frontal armor and 80mm of side armor. The T-80BV, on the other hand, has a 430mm front and 80mm side armor.