Vickers Main Battle Tank Mark 4

The Vickers MBT Mk. 4 later known as the Vickers Valiant is a main battle tank developed as a private venture by British company Vickers for export. Its development began in 1976 and ended in January 1984. Although the Valiant did not enter production, its development provided valuable experience in the production of an aluminium-hulled, Chobham-armoured tank in the 40 tonnes weight range. A further development of its turret was later used for the Vickers Mk. 7 MBT.

Vickers MBT Mk. 4
Type	Main battle tank
Place of origin	United Kingdom
Production history
Unit cost	$1.39 million (1993)[1]
Specifications
Mass	43.6 t (47 t with the "Universal Turret")
Length	7.51 m (24 ft 8 in) hull 10.62 m (34 ft 10 in) with gun forward
Width	3.3 m (10 ft 10 in) 3.6 m (11 ft 10 in) with appliqué armour
Height	2.48 m (8 ft 1.64 in)
Crew	4 (commander, gunner, loader and driver)
Armour	Chobham
Main armament	105 mm L7A1 rifled gun or 120 mm L11 rifled gun or 120 mm Rh-120 smoothbore gun
Secondary armament	McDonnell-Douglas Helicopter Co 7.62 mm chain gun
Engine	GM Detroit Diesel 12V-71T and later Rolls-Royce CV12 TCA Condor 915 hp (682 kW) 1,000 hp (750 kW)
Power/weight	20.9 hp/t–21.2 hp/t
Transmission	TN 12-1000
Suspension	torsion bar
Ground clearance	50 cm (1 ft 8 in)
Fuel capacity	1,130 litres (249 imperial gallons; 299 US gallons)
Operational range	550 km (340 mi)
Maximum speed	61.2 km/h (38.0 mph).[2]

History

In August 1977, Vickers produced a design for a vehicle that incorporated Chobham composite armour protection within a battle weight of 43 tonnes. This first prototype, designated the Vickers Main Battle Tank Mark 4, mounted the L7 105 mm rifled gun and, in 1978, underwent automotive tests with the Rolls-Royce CV12 TCA developing 1000 bhp and with the General Motors Detroit Diesel 12V-71T developing 915 bhp.

The prototype of the Mk. 4 was firstly exhibited at the British Army Equipment Exhibition in June 1980, along with a mock-up of a new universal turret fitted with a 120 mm L11 gun. By the time of the British Army Equipment Exhibition in June 1982, the tank had undergone extensive testing with the new turret. The design of the Universal Turret was a radical change from the original and included installation of many state-of-the-art components. This quantum leap in turret evolution led to a decision to give the Mk. 4 a new identity, and it was renamed the " Valiant ".[3]

In early 1983, the Valiant was tested in Middle East and its development was completed in January 1984. Although the tests of the Valiant in the Middle East indicated that the Valiant tank had excellent firepower and fire control components, the mobility characteristics were deficient, leading to the termination of its marketing effort in July 1985.[4] The fate of the prototypes is unknown.

Design

Fire control and observation

Gunner

The gunner was provided with a Vickers Instruments L30 telescopic laser sight as a main sight. The sight was monocular, with a magnification of ×10, and was fitted with a Neodimium-YAG laser rangefinder and a cathode-ray tube for injection of fire-control data. In addition to his main sight, the gunner was also provided with a Vickers Instruments GS10 periscopic sight. This was mounted in the turret roof and provided a ×1 wide angle field of view and was used for surveillance and target acquisition.

Commander

The commander had a ring of six fixed ×1 periscopes around his hatch to give all-around vision. The commander's main sight was a French SFIM VS580-10 gyrostabilized panoramic sight. Two degrees of magnification ×3 and ×10 were provided, it also incorporated a Nd-YAG laser rangefinder. In addition, a gyrostabilised panoramic thermal sight, the Dutch Philips-USFA UA 9090, was also mounted on the turret roof, in front of the loader's hatch.

Loader

The loader has at his disposal one rotating periscope.

Driver

The driver was originally provided with only one vision block which was later supplemented by two side-looking vision blocks.

Protection

The basic hull structure of the Valiant was fabricated from aluminium armour, allowing optimum use of Chobham armour within an overall weight of 47 tonnes. Emphasis was placed upon frontal protection covering a 60° arc. In addition, however, Chobham armour was also applied along the full length of the hull sides (heavy ballistic skirts). The turret structure was made of welded steel plates, with a layer of Chobham armour added to the front and sides.[3]

Armament

Primary

The first prototype was armed with a Royal Ordnance L7 105 mm rifled gun, 56[3] to 60[2] rounds are carried, 30 of which are stowed in the hull, to the left of the driver.

In 1982 it was rearmed with the Royal Ordnance L11 120 mm rifled gun, 42[2] to 52[3] rounds are carried, 21 rounds are stowed in the hull, to the left of the driver. Alternatively, the Valiant can be armed with the Rheinmetall Rh-120 120 mm smoothbore gun, 44 rounds are carried[3], 28 rounds are stowed in the hull, to the left of the driver.

Secondary

The secondary armament of the Mk. 4 includes a 7.62 mm FN MAG coaxial machinegun which was later replaced on the Valiant's Universal Turret by a 7.62 mm Hughes EX-34 Chain Gun. This externally-powered weapon has been adopted because of the advantages it offers to the crew, including its ability to eject faulty rounds without a stoppage of the gun and the elimination of gun fumes in the turret.

Mobility

Engine

The Mk. 4 was first fitted with a General Motors Detroit Diesel 12V-71T engine[5] developing 915 bhp and subsequently fitted a Rolls-Royce V-12 diesel engine, the CV12 TCA Condor, virtually the same engine as that fitted in the British Army FV4030/4 Challenger 1 main battle tank, but is rated at 1000 bhp instead of 1200 bhp. The lower power rating increase its durability and, because it is less highly turbocharged, its response is more rapid, which increases the tank acceleration. The engine has a minimum specific fuel consumption of 207 g/(kW⋅h).

Transmission

The transmission of the Valiant does not follow the trend to use torque converters and hydrostatic steering. Instead, it is a modified version of the six-speed TN-12 transmission produced for the FV4201 Chieftain, but made fully automatic by means of an electronic control system.[6] The all-mechanical transmission has the inherent advantage of being more efficient, which means that more of the engine power is available to drive the tank, instead of being dissipated by oil coolers. At the same time, the skill and effort generally required of drivers by mechanical transmissions are eliminated by the electrical controls.

Suspension

The suspension of the Valiant is almost the only feature carried over with little change from the Vickers Mark 1 and Mark 3 MBTs. In principle, it is of a conventional, torsion bar type, but it is unique in having secondary torsion bar springs in the trailing arms of the first two and the last road wheels on each side. The secondary torsion bars provide more effective springing at the most critical wheel stations and significantly improve the ride over rough ground. The total vertical wheel travel is 303 mm (bump : 202 mm / rebound : 101 mm)[2]

Additional specifications

• Ground pressure: 0.916 kg/cm²
• Power/weight ratio: 23,3 bhp/t
• Maximum gradient 58%
• Maximum tilt: 30%
• Trench: 3 m
• Vertical obstacle: 0.914 m
• Fording depth: 1,1 m
• Gun control: Marconi Command and Control Systems Centaur I fully integrated gun-and-fire control system
• Fire control system: Marconi Radar SFCS 600

See also

• Vickers MBTs
• AMX-32 (French counterpart)
• FV4201 Chieftain
• FV4034 Challenger 2

References

1. "Valiant". mainbattletanks.czweb.org (in Czech). Retrieved 29 February 2020.
2. Jenkins, D.H.C. (1981). Le Vickers Valiant et l'AMX-32, deux poids moyens sur le même ring (in French). Revue Internationale de Défense. p. 1668.
3. Foss, Christopher F.; McKenzie, Peter (1988). The Vickers Tanks: From Landship to Challenger. Patrick Stephens Limited. p. 256. ISBN 9781852601416.
4. "Vickers Tanks - Archived 1/2005". forecastinternational.com. Retrieved 1 March 2020.
5. Dunstan, Simon (2020). British Battle Tanks: Post-war Tanks 1946–2016. Osprey Publishing. p. 304. ISBN 978-1472833365.
6. Ogorkiewicz, R. M. (September 1973). AFV Weapons Profile. Duncan Crow. p. 21.