The Chieftain FV4201 was the main battle tank of the United Kingdom during the 1960s, 1970s
and 1980s. It was one of the most advanced tanks of its era, and at the time of its introduction
in 1966 had the most powerful main gun and most effective armour of any tank in the world.
The Chieftain also introduced a supine driver position, enabling a heavily sloped hull with
reduced height. It remained in service until replaced with the Challenger 1.
Development The Chieftain was an evolutionary development
of the successful cruiser line of tanks that had emerged at the end of the Second World
War. British engineers had learned during the war that their tanks often lacked sufficient
protection and firepower compared to those fielded by the enemy, and that this had led
to high casualty levels when faced with the superior German tanks in World War II. Centurion
addressed this to a great degree, combining higher levels of armour and an improved gun,
which made it at least equal to any of the contemporary medium tanks. However, the introduction
of the Soviet IS-3 heavy tank forced the introduction of their own Conqueror heavy tank, armed with
a 120 mm gun. A single design combining the firepower of the Conqueror's 120 mm gun with
the mobility and general usefulness of the Centurion would be ideal.
Leyland, who had been involved in Centurion, had built their own prototypes of a new tank
design in 1956, and these led to a War Office specification for a new tank. The General
Staff specification drew on experience of Centurion in the Korean War and Conqueror.
The tank was expected to be able to engage the enemy at long range and from defensive
positions, be proof against medium artillery. To this end the gun was to have a greater
angle of depression than the 8 degrees of Conqueror and better frontal armour. The tank
was expected to achieve 10 rounds per minute in the first minute and six per minute for
the following four. The first few prototypes were provided for
troop trials from 1959, this identified a number of changes. Changes to address engine
vibration and cooling resulted in redesign of the rear hull. This increased the design
weight to nearly 50 tons and as such the suspension was strengthened. Track pads had to be fitted
to protect roads from damage and the ground clearance increased. The design was accepted
in the early 1960s. Britain and Israel had collaborated on the
development in its latter stages with a view to Israel purchasing and domestically producing
the vehicle. Two prototypes were delivered as part of a four year trial. It was eventually
decided not to sell the marque to the Israelis however which prompted Israel to follow its
own development programme. In 1957 NATO had specified that its forces
should use multi-fuel engines. The early BL Engine delivered around 450 bhp to the sprocket
which meant a top road speed of around 25 mph and cross country performance was limited.
This was further hampered by the Horstmann coil spring suspension, which made it a challenge
to drive cross country and provide the crew with a comfortable ride. Due to the cylinder
linings being pressure fitted, coolant leaks within the cylinder block were common, resulting
in white smoke billowing from the exhaust. In the late 1970s engine design changed with
the introduction of Belzona which was used to improve the lining seals. Engine output
also increased with later engines delivering some 850 bhp to the sprocket. This meant
better performance and an increased speed. Cross-country performance remained limited,
however. Several aspects of Chieftain design were trialled
by the production of the FV4202 "40-ton Centurion" with a reclined driver position and mantleless
gun mounting. Design
Chieftain design included a heavily sloped hull and turret which greatly increased the
effective thickness of the frontal armour - 388 mm on the glacis), and 390 mm on the
turret). It had a mantletless turret, in order to take full advantage of reclining the vehicle
up to ten degrees in a hull-down position. For security reasons, early prototypes had
a canvas screen covering the mantlet and a sheet metal box mounted over the sloping glacis
plate to disguise the configuration of the vehicle.
The driver lay semi-recumbent in the hull when his hatch was closed down, which helped
to reduce the profile of the forward glacis plate. The commander, gunner and loader were
situated in the turret. To the left side of the turret was a large searchlight with infra-red
capability in an armoured housing. The Leyland L60 engine is a two-stroke opposed
piston design intended for multi-fuel use so that it could run on whatever fuel was
available. In practice the engine did not deliver the expected power, and was unreliable,
estimated to have a 90% breakdown rate, but improvements were introduced to address this.
Primary problems included, cylinder liner failure, fan drive problems and perpetual
leaks due to vibration and badly routed pipework. However, as the engine power improved the
tank itself became heavier. The tank was steered by conventional tillers
hydraulically actuating onto external brake discs. The discs worked via the epicyclic
gearbox providing "regenerative" steering. The gearbox was operated motorcycle-style
with a kick up/kick down "peg" on the left which actuated electro-hydraulic units in
the gearbox; the accelerator was cable operated by the right foot. In the turret the loader
was on the left and the gunner on the right of the gun with the commander behind the gunner.
The suspension was of the Horstmann bogie type, with large side plates to protect the
tracks and provide stand-off protection from hollow charge attack.
The main armament was the 120 mm L11A5 rifled gun. This differed from most contemporary
main tank armament as it used projectiles and charges which were loaded separately,
as opposed to a single fixed round. The charges were encased in combustible bags. Other tank
guns, such as on the Conqueror, needed to store the spent shell cartridges or eject
them outside. The combustible charges were stored in 36 recesses surrounded by a pressurized
water/glycol mixture - so-called "wet-stowage". In the event of a hit which penetrated the
fighting compartment, the jacket would rupture, soaking the charges and preventing a catastrophic
propellant explosion. As there was no shell case, the firing of the charge was by vent
tubes automatically loaded from a magazine on the breech. Due to the length of the gun
which required balancing and the need for storage space, the turret has a large overhang
to the rear. This contains radios, ammunition, fire control equipment and has further stowage
externally. The gun could fire a wide range of ammunition,
but the most commonly loaded types were high explosive squash head, armour-piercing discarding
sabot, or practice round equivalents for both types. Chieftain could store up to 64 projectiles.
The gun was fully stabilised with a fully computerized integrated control system. The
secondary armament consisted of a coaxial L8A1 7.62 mm machine gun, and another 7.62 mm
machine gun mounted on the commander's cupola. Chieftain had an NBC protection system, which
Centurion lacked. The initial Fire-control system was the Marconi
FV/GCE Mk 4. A .50-inch ranging gun was mounted above the main gun. This fired ranging shots
out to a maximum of 2,600 yards, at which point the tracer in the ranging rounds burned
out. The tank commander had a rotating cupola with nine vision blocks -giving all round
view - and a periscope, plus the 7.62 mm machine-gun and an infrared projector coaxial
with the weapon. The aiming systems were provided for both gunner and tank commander; they had
1x or 8x selectable magnification power, and they were replaceable with IR vision systems
for the night operations. The commander could rotate his cuplola to bring his sight onto
a target and then engage the mechanism that brought the turret round on to the correct
bearing so that the gunner could complete the aiming.
The left side of the turret had a large searchlight with an infra-red filter inside an armoured
box, with a relatively long range – up to 1–1.5 kilometres.
From the beginning of the 1970s, the Mk 3/3 version replaced the ranging gun with a Barr
and Stroud LF-2 laser rangefinder with a 10 km range. This allowed engagements at much longer
ranges, and also could be linked to the fire control system, allowing more rapid engagements
and changes of target. On later models fire control was provided
by the Marconi IFCS, using a digital ballistic computer. The upgrade was not finished until
the end of 1980, when some examples had the IR searchlight replaced with TOGS. Many later
examples had Stillbrew armour, meant to face Soviet 125 mm tank guns and heavy anti-tank
missiles. These became the Mark 13 version. Service
Like its European competitors, Chieftain found a large export market in the Middle East,
but unlike Centurion, it was not adopted by any other NATO or Commonwealth countries.
Chieftain proved itself capable in combat and able to be upgraded with enhancements
both for overall improvement and to meet local requirements. The marque was continuously
upgraded until the early 1990s when it was replaced by Challenger 1. The final Chieftain
version used by the British Army until 1995, incorporated "Stillbrew" armour named after
Colonel Still and John Brewer from the Military Vehicles and Engineering Establishment, the
Improved Fire Control System and the Thermal Observation Gunnery Sight.
The first model was introduced in 1967. Chieftain was supplied to at least six countries, including
Iran, Kuwait, Oman and Jordan. An agreement for sales to Israel and local production was
cancelled by the British Government in 1969, despite considerable Israeli technical and
tactical input into the development of the tank, especially in desert environments, and
the use of hull-down to maximum effect in the final design. 2 examples were delivered
to and extensively trialled by, the Israeli Armoured Corps. This experience spurred the
creation of the indigenous Israeli Merkava, the development programme of which was led
by General Israel Tal, who had worked closely with the British in the Anglo-Israeli Chieftain
project. The largest foreign sale was to Iran, which at the recommendation of General Tal,
took delivery of 707 Mk-3P and Mk-5P, 125–189 FV-4030-1, 41 ARV and 14 AVLB before the 1979
revolution. Further planned deliveries of the more capable 4030 series were cancelled
at that point. The tank was heavily used during the Iran–Iraq War of 1980-88 with mixed
results, engine breakdowns being a common issue. Chieftains participated in the biggest
tank battle of the war in early 1981. Iran lost 200 Chieftain and M60A1 tanks in battle.
In return, Iraq lost 50 T-62 tanks. Only 60 Chieftains managed to survive the war with
Iraq. Kuwaiti Chieftains participated in the 1990
Iraq–Kuwait War. The Kuwaiti 35th Armored Brigade fought at the Battle of the Bridges
against elements of the Iraqi Hammurabi and Medina divisions before withdrawing over the
Saudi border 136 tanks were captured by Iraq. Only 7 tanks managed to survive the war with
Iraq. Media
A Chieftain Mk 5 being driven on Salisbury Plain appears on the cover of the 1971 Uriah
Heep album Salisbury Specifications
Crew: 4 Combat weight: 55 tons
Overall length: 10.8 m gun forward Hull length: 7.5 m
Height: 2.9 m Width: 3.5 m
Powerplant: Leyland L60 695 bhp Range: 500 km
Maximum road speed: 48 km/h Cross-country speed: 30 km/h
Armour: turret front, 195 mm RHA Armament
120 mm L11A5 rifled tank gun Rate of fire: 10 rounds per minute for the
first minute and 6 thereafter. Elevation: -10 to +20 degree
Laser rangefinder
Coaxial L8A1 7.62 mm machine gun Cupola-mounted L37A1 7.62mm machine gun
Mark 1 and Mark 2 models had a coaxial Browning .50-inch ranging machine guns prior to the
introduction of the laser rangefinder. Equipment
Twin Clansman VRC 353 VHF Radio sets 1 C42 1 B47 Larkspur VHF radios
2 X 6-barrel smoke dischargers on turret Bulldozer blade
Variants Chieftain Mk 1
40 training vehicles for 1965–1966. Issued to 1 RTR and 5 RTR for troop trials.
Chieftain Mk 2 First service model with 650 hp engine.
Chieftain Mk 3 Extra equipment fitted giving rise to several
sub-marks. New cupola. Chieftain Mk.5
Final production variant, with upgrades to the engine and NBC protection system.
Chieftain Mk.6-9 Incremental upgrades to earlier Marks of tanks,
including addition of Clansman radios. Chieftain Mk.10
Mark 9 upgrade, addition of Stillbrew Crew Protection Package to the turret front and
turret ring. Chieftain Mk.11
Mark 10 upgrade, searchlight replaced with the Thermal Observation and Gunnery System,
manufactured by Barr and Stroud. Chieftain Mk.12/13
Proposed further upgrades, cancelled when the Challenger 2 was introduced.
Chieftain 900 Chieftain with Chobham armour
FV4205 AVLB Bridge-laying vehicle
FV4204 ARV/ARRV Armoured Recovery Vehicle, Armoured Recovery
and Repair Vehicle.
Chieftain AVRE Armoured Vehicle Royal Engineers, a British
Army combat engineering variant used by the Royal Engineers.
Chieftain Marksman self-propelled anti-aircraft gun version,
equipped with the Marksman twin gun turret. Chieftain Mineclearer
Mine-clearing development. Chieftain Sabre
Twin 30 mm AA turret.
Khalid/Shir 1 Jordanian with the running gear of the Challenger
1. Basically this was a transition vehicle from the Chieftain to the Shir 2 which had
been intended for Iran but was subsequently cancelled. The Shir 2 tanks became Challenger
1 tanks after reworking at ROF Leeds. The vehicle chassis comprised the front half of
a Chieftain Hull, Chieftain running gear and the rear of a 4030/2 Chassis. This allowed
the fitment in the engine bay of a Rolls-Royce CV12 engine producing 1200 bhp at 2,300 rpm.
Weapon Carriers The Chieftain chassis was modified to mount
air defence weapons and a 155 mm howitzer in various modifications.
Shir 2 Iranian variant. Visible external differences
from Chieftain Mk.5 included a sloping rear hull, Removal of the Searchlight from the
left turret area and storage baskets refitted, water channel removed from around drivers
hatch on the glacis plate, modified light clusters also on the glacis plate, Larger
sight housing on commanders cupola. Mobarez Tank
Iranian upgraded version of Chieftain. Operators
Iran: 707 Mk-3P and Mk-5P, 125–189 FV-4030-1, 41 ARV and 14 AVLB obtained before the 1979
revolution. Further planned deliveries of the more capable 4030 series were cancelled
at that point. 100 in service as of 2005.. Jordan: 274 Khalid delivered between 1981-1985
+ 90 MK5/5 From Iraq. 350 in service Oman: 27 delivered 1981–85.
Former operators United Kingdom: Used from 1965 to 1995.
Kuwait: 175 in 1976, 143 in 1989, 20 in 1995, 17 in storage in 2000.
Iraq: 50-75 tanks in service with Iraqi Army in 1990. Most upgraded to Khalid-level
with Air-conditioning for crew and reinforced armour and night vision.
Israel: 2 delivered for the joint Anglo-Israeli developmental project. In Israeli Armored
Corps service for trials 1965-69. See also
Centurion tank Merkava tank
M60 tank T-62
T-72 T-64 : Approximate Soviet equivalent
References Notes
Bibliography Norman, Michael, AFV Profile No. 18 Chieftain
and Leopard, Profile Publishing External links
FAS.org Chieftain Tank