4201 Chieftain was the main battle tank of the United Kingdom during the 1960s and 1970s.
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 heaviest
armour of any tank in the world. The Chieftain also introduced a
supine (lying backwards) driver position, enabling a heavily sloped
hull with reduced height.
The Chieftain was a radical evolutionary development of the
line of tanks
that had emerged at the end of the Second
. The British 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
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 design was
accepted in the early 1960s. Chieftain was designed to be as well
protected as possible and to be equipped with a powerful
120 mm rifled gun. The heavy armour came at the price of
reduced mobility, chiefly due to engine power limitations, which
was perhaps the Chieftain's main drawback. The engine selected took
the multi-fuel route and as introduced gave less than the planned
output; improvements to the engine did not increase power to the
The Chieftain design included a heavily sloped hull and turret
which greatly increased the effective thickness of the frontal
armour - 388mm (15.28") on the glacis (from an actual thickness of
120mm), and 390mm (15.35") on the turret (from 195mm). It had a
turret, in order to take full
advantage of reclining the vehicle up to ten degrees in a hull-down
position. The driver lay semi-recumbent in the hull when his hatch
was closed down which helped to reduce overall height. The
commander, gunner and loader were situated in the turret. To the
left side of the turret was a large infra-red searchlight in an
armoured housing. The suspension was of the Horstmann
bogie type, with large side plates to
protect the tracks and provide stand-off protection from hollow
The engine is a two-stroke opposed piston
design intended for multi-fuel
use so it could run on petrol or
diesel or anything in between. 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. In reality the discs and pads
became soaked in oil and diesel and the steering became difficult.
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 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 had to store the
spent shell cartridges or eject them outside.) The combustible
charges were stored in 36 recesses surrounded by water jackets. In
the event of a hit which penetrated the fighting compartment, the
water jacket would rupture, soaking the charges and preventing a
catastrophic ammunition explosion. The gun itself could fire a wide
range of ammunition, but the most commonly loaded types were
(High explosive squash head) or APDS
(Armour-Piercing Discarding Sabot), or practice
round equivalents for both types. When the Chieftain was first
introduced, a 12.7mm ranging machine gun was mounted above the main
gun. This fired ranging shots out to a maximum of , at which point
the tracer in the ranging rounds burned out. Later, in the late
1970s and early 1980s, a Barr and
Stroud laser rangefinder
replaced the ranging machine gun. 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. 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.
European competitors, the Chieftain found a
large export market in the Middle East,
but unlike the earlier Centurion, it was not adopted by any other
NATO or Commonwealth countries.
The Chieftain proved itself capable in combat and able to be
upgraded with enhancements both for overall improvement and to meet
local requirements. The Chieftain tanks were continuously upgraded
until the early 1990s when they were replaced by the Challenger
series of tanks whose design
was influenced by that of Chieftain. 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
(MVEE), the Improved
Fire Control System (IFCS) and the Thermal Observation Gunnery
The first Chieftain model was introduced in 1967. Chieftains were
supplied to at least six countries, including Iran, Kuwait, Oman and Jordan.
agreement for sale of Chieftains to Israel was
cancelled by the British Government in 1969 .
foreign sale was to Iran, which took delivery of around 1,000
"Mk5(P)" before the 1979
. Further planned deliveries of the more capable 4030
series were cancelled at that point. The tank's main combat
experience was in the Iran–Iraq
- 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 (diesel) 695 hp
- Range: 500 km
- Max Road Speed: 48 km/h
- Cross-Country Speed: 30 km/h
- Armour: turret front, 195 mm RHA (60°)
Mark 1 and Mark 2 models had coaxial .50 cal. ranging machine guns
prior to the introduction of the laser rangefinder.
- Twin Clansman VRC 353 VHF Radio sets
- 1 C42 1 B47 Larkspur VHF
- 2 X 6-barrel smoke dischargers on turret
- Bulldozer blade (optional - fitted to one tank per
- Chieftain Mk 1
- 40 training vehicles for 1965/1966.
- Chieftain Mk 2
- First service model with 650 hp engine.
- Chieftain Mk 3
- Extra equipment fitted giving rise to several submarks.
- Chieftain Mk.5
- Final production variant, with upgrades to the powerplant 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 (TOGS), manufactured by Barr and
- Chieftain Mk.12/13
- Proposed further upgrades, cancelled when the Challenger 2 was introduced.
- FV4205 AVLB: Bridge-laying vehicle.
- FV4204 ARV/ARRV
- Armoured Recovery Vehicle, Armoured Recovery and Repair
- Chieftain Marksman: SPAAG version, equipped with the Marksman turret.
- Chieftain Mineclearer
- Mine-clearing development.
- Chieftain Sabre
- Twin 30 mm AA turret.
- Khalid (also designated 4030P2J - P = Phase & J =
- Jordanian / Iranian variant with running gear of the Challenger
1. Basically this was a transition vehicle from the Chieftain to
the Shir2 which had been intended for Iran but was subsequently
cancelled. The Shir2 tanks became Challenger1 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 (Sloping Hull). This allowed the fitment in the engine bay
of a Rolls CV8 engine.
- Weapon Carriers
- The Chieftain chassis was modified to mount air defence weapons
("Marksman" 2 x 35 mm cannon) and a 155 mm howitzer in
- Shir 2
- Iranian variant. Visible external differences from the
Chieftain Mk5 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.
- British Army - used from 1965 to
- - ~1,000 Chieftain Mark 5(P) obtained before the 1979
revolution. Further planned deliveries of the more capable 4030
series were cancelled at that point. 100 as of 2005. (100 in 1990,
250 in 1995, 140 in 2000, 200 in 2002).
- - 30 in service with Iraqi Regular Army in 1990. All destroyed
- - 90
- - 45 in 1989, 20 in 1995, 17 in storage in 2000.
- - 27
- Richard M. Ogorkiewicz, Jane's - The Technology of
Tanks, Jane's Information Group, p.69
- Richard Ogorkiewicz, Cold War, Hot Science: Applied
Research in Britain's Defence Laboratories 1945-1990 (2002),
p.128-129, edited by Robert Bud & Philip Gummett, NMSI Trading
Ltd, ISBN 1900747472
- Files reveal British-Israel tank secrets BBC News 2
- globasecurity.org Iranian Ground Forces
- globalsecurity.org Kuwait Army Equipment