Strv 81 (RB 52) (Great Britain)

Description

The ' (Full name: Stridsvagn 81 (Rb.52)') is a gift rank British medium tank with a battle rating of (AB), (RB), and (SB). It was introduced in Update 1.59 "Flaming Arrows". A Swedish import of the British Centurion Mk 3, it features an add-on of three SS.11 anti-tank missile on the turret. It uses the MCLOS guidance system (SACLOS in arcade mode), which means that the missiles must be manually guided by the tank movement keys to their target.

General info

Survivability and armour

Armour type:

• Rolled homogeneous armour (Hull, Turret roof)
• Cast homogeneous armour (Turret)

Armour	Front	Sides	Rear	Roof
Hull	76.2 mm (58°) Front glacis 76.2 mm (47-48°) Lower glacis	50.8 (12°) + 6 mm	38 mm (8-12°)	29 mm 8-14 mm Engine deck
Turret	152 mm (6-27°) Turret front 152 mm Gun mantlet	89 mm (5-12°)	89 mm (1-18°)	50.8 mm Border of turret 29 mm Center of turret
Armour	Front	Rear	Roof
Cupola	152 mm	90 mm	29 mm

Notes:

• Suspension wheels and tracks are both 20 mm thick.
• The steel boxes around the turret and hull give a 4 mm additional protection, though this seems to be a negligible addition.
• ATGM attached outside the turret act as ammo racks and can be detonated
• Spaced armour plates are placed on the side of the Centurion, giving an additional 6 mm of side armour.

Mobility

Mobility characteristic
Weight (tons)	Add-on Armour weight (tons)	Max speed (km/h)
50.8	N/A	39 (AB)
		35 (RB/SB)
Engine power (horsepower)
Mode	Stock	Upgraded
Arcade	1,007	1,240
Realistic/Simulator	575	650
Power-to-weight ratio (hp/ton)
Mode	Stock	Upgraded
Arcade	19.82	24.41
Realistic/Simulator	11.32	12.79

Armaments

Main armament

84 mm OQF 20-pounder Mk.I
Capacity			Vertical guidance	Horizontal guidance	Stabilizer
65			-10°/+20°	±180°	Two-plane
Turret rotation speed (°/s)
Mode	Stock	Upgraded	Prior + Full crew	Prior + Expert qualif.	Prior + Ace qualif.
Arcade	10.7	14.8	__.__	__.__	__.__
Realistic	10.7	12.6	__.__	__.__	__.__
Reloading rate (seconds)
Stock	Prior + Full crew	Prior + Expert qualif.	Prior + Ace qualif.
8.1	__.__	__.__	__.__

Ammunition

Penetration statistics
Ammunition	Type of warhead	Penetration in mm @ 0° Angle of Attack
		10m	100m	500m	1000m	1500m	2000m
8,4 cm Slpprj	APCBC	231	229	216	200	186	173
8,4 cm Slsgr m/53	HE	15	15	15	15	15	15
8,4 cm Slpprj m/54	APDS	285	283	262	239	218	198

Shell details
Ammunition	Type of warhead	Velocity in m/s	Projectile Mass in kg	Fuse delay in m:	Fuse sensitivity in mm:	Explosive Mass in g (TNT equivalent):	Normalization At 30° from horizontal:	Ricochet:
								0%	50%	100%
8,4 cm Slpprj	APCBC	1,000	9.1	N/A	N/A	N/A	+4°	48°	63°	71°
8,4 cm Slsgr m/53	HE	600	7.5	0.4	0.5	1,130	+0°	79°	80°	81°
8,4 cm Slpprj m/54	APDS	1,400	3.2	N/A	N/A	N/A	+1.5°	75°	78°	80°

Smoke characteristic
Ammunition	Velocity in m/s	Projectile Mass in kg	Screen radius in m	Screen time in s	Screen hold time in s:	Explosive Mass in g (TNT equivalent):
8,4 cm Rökgr m/53	250	9.3	13	5	20	50

Ammo racks

Ammo racks of the Strv 81.

Full ammo	1st rack empty	2nd rack empty	3rd rack empty	4th rack empty	Visual discrepancy
65	62 (+3)	33 (+32)	17 (+48)	1 (+64)	No

Turret empty: 62 (+3)
Front empty: 33 (+32)

Additional armament

164 mm Robot-52 (SS11) ATGM
Capacity			Vertical guidance	Flight speed (m/s)	Range (m)
3			N/A	150	6,500

Ammunition

Penetration statistics
Ammunition	Type of warhead	Penetration in mm @ 90°
		10m	100m	500m	1000m	1500m	2000m
Rb.52	ATGM	600	600	600	600	600	600

Shell details
Ammunition	Type of warhead	Velocity in m/s	Projectile Mass in kg	Fuse delay in m:	Fuse sensitivity in mm:	Explosive Mass in g (TNT equivalent):	Normalization At 30° from horizontal:	Ricochet:
								0%	50%	100%
Rb.52	ATGM	150	30	0.0	0.1	4,550	+0°	65°	70°	75°

Ammo racks

Full ammo	1st rack empty	2nd rack empty	3rd rack empty	Visual discrepancy
3	2 (+1)	1 (+2)	0 (+3)	No

Machine guns

7.92 mm BESA
Coaxial mount
Capacity (Belt capacity)				Fire rate (shots/minute)	Vertical guidance	Horizontal guidance
3,600 (225)				600	N/A	N/A

Usage in battles

The Stridsvagn 81 is essentially the Centurion Mk.3. It is an effective medium tank if played to its strengths.

If one wants to keep it simple, just use the powerful gun to snipe from distance.

More advanced tankers can utilize the not too impressive max speed (35kmph/22mph) to move with this medium tank into the flanks of enemy tanks (close to the border of a map) and search for positions like hills and ridges where one can make use of the amazing -10° gun depression to hide the vulnerable lower plate of this tank. Once in position, one should use the binoculars to scout for enemies without exposing the turret. If an enemy tank is spotted that could be a potential threat, pop out a little bit and start to take out the enemies gunner/cannon barrel/cannon breech to prevent him from returning fire. Now utilize the quick reload to take out one crew member after the other to finish off the opponent. If an enemy is spotted who is exposing their side or even the rear while not aiming towards the Strv 81, shoot the engine first to immobilize and possibly even ignite the enemy tank, preventing him to take cover. The next shots should again disable the gun of the enemy, now finish the prey by shooting all crew members or, if feeling lucky, shoot an ammo rack.

The best choice to pierce enemy tanks is obviously the Shot Mk.3 (APDS) although it is quite expensive in terms of Silver Lions. The Shot Mk. 1 (APCBC) works in most situation as well but lacks penetration compared to the Mk. 3 APDS shot. The amazing penetration characteristics of this APDS shot enables this gun to pierce front plates of all Panther models (apart from the Panther II) to ranges up to 2000m. T-44s and Panther IIs front plates can be penetrated to ranges up to almost 1000m. Keep in mind though that the front plate of the T-44 is angled at 60°, so it bounces even this powerful APDS shot quite often. Even the front plate of the mighty Tiger II is not able to stop this APDS shot if not angled and the range is shorter than 100m. However, aside from the gun, the Strv 81 has access to three potent anti-tank guided missiles.

In a head to head situation with an enemy tank approaching try to angle the Strv 81 not more than 5° degrees to either side since the side armour is quite weak (50.8mm), try to hide the lower front plate which is a massive weak spot, while reloading turn the turret 10° to the right to maximize chances of bouncing shots (right side of the turret front has some extra armour) and keeping the gunner alive.

How to use an ATGM
The addition of the ATGM means the Strv 81 has the potential to act as a long-range support vehicle from the rear lines or the flanks. Prop up the Centurion in a well fortified and safe location and use it as a base of fire and launch missiles onto the enemies' front or sides. With the high amount of penetration available on the SS.11 missiles, even a glancing hit can do massive damage to the hit enemy tank.

The SS.11 missiles attached to the right side of the Strv 81 turret provide up to 600 mm of penetration upon impact, making all but the most deflected shots potent to any targets. Three are available for immediate usage and are guided by a MCLOS system. The missile have a trajectory of going up for a distance before leveling, creating a "dead zone" of up to 200 meters that the missile cannot adequately engage in.

In arcade mode, the missile guidance system is relatively uncomplicated in aiming. Simply aim the crosshair onto the desired target and the missile will adjust to fit into the crosshair. The guidance system is sensitive as such it is not recommended to rapidly swing the crosshair around during the missile trajectory to keep it stable and on track. Once depleted, the missile will gradually reload to refill the launch racks.

In realistic and simulator mode, the missile is guided by the tank movement keys of [W], [A], [S], and [D]. [W] and [S] moves the missile vertically while [A] and [D] moves the missile horizontally. The guidance system will not activate until the missile clears its dead zone. The system is sensitive as such it is not recommended to rapidly tap the keys for movement else the missile moves out of the scope and away from the controls. Once depleted, the missile will not automatically reload and must be driven onto a captured control point for reloads.

Pros and cons

Pros:

• Powerful and high penetrating gun
• Very quick reload time
• Wide gun depression and elevation
• Neutral steering
• Good reverse speed
• Great RP and SL grinder
• Has three ATGM missiles

Cons:

• Mediocre speed and acceleration
• Ammo rack in the front (will be empty if 33 rounds are loaded)
• Small internal compartment (only 4 crew members), easy to one shot
• APDS shot causes only punctual damage (aim carefully)
• No explosive filler on any AP shells
• Weak side armour
• ATGMs are first generation - requires the use of WASD keys to operate it (In RB and SB game modes)
• ATGMs can explode if hit and destroy the turret

History

Development

The tank's concept was made in 1943 when the Directorate of Tank Design, under Sir Claude Gibb, was asked to produce a new heavy cruiser tank for the General Staff under the designation A41, which was to become the standard of a British "Universal Tank" to replace the separated "infantry" and "cruiser" tanks currently used. As World War II progressed and the Germans unveiled their heavier tanks with an 88 mm cannon like the Tiger, War Office made a revision to their design requirements to counter this threat. The requirements now include an increased durability and reliability, with the ability to protect itself against the 88 mm gun and mines, an agility similar to the Comet tank and with good reverse speed, all while staying under a 40 ton weight.

Responding to these requirements, the department developed a larger hulls by adapting the suspension on the Comet, lengthening with another road wheel and spacing between the wheels. The standard Christie suspension used on the previous cruiser tanks was replaced by the Horstmann suspension, which uses coil springs on two-wheel bogies on each side and is proven to be easier to maintain than the Christie suspension. The hull used a welded and sloped armour with a cast turret mounting the famous 17-pounder cannon. The speed of the tank would be established by using the Rolls Meteor engine previously used on the Comet and Cromwell. Despite these changes, the department concluded that the weight restriction would not allow the tank design to withstand the 88 mm rounds. The weight restriction was done so the tank would be able to be carried around in the Mk.I and Mk.II transport trailers, which had a 40-ton load. This restriction was rescinded to allow more freedom in the tank design, which showed potential to War Ministry. The heavier tank designs developed had armour equivalent to the heaviest infantry tanks like the Churchill tank, yet with superior cross-country mobility due to improved suspension and engines.

The tank was given the name Centurion and the first mock-ups of the design was made by AEC and was presented in May 1944. After that, 20 pilot models were ordered with a various armament combinations. Ten had a 17-pounder and a 20 mm Polsten gun (5 with a machine gun in turret rear, 5 with an escape door instead), five had a 17-pounder and a BESA machine gun and an escape door, five more with the 77 mm HV gun with a driver operated hull machine gun. The prototypes of the 40-ton design, the Mk.1, had a 76 mm armour on the front glacis, which was made very powerful with the heavy sloping design on the tank. Added with a 152 mm thick turret armour, the Centurion became a very protected tank design, yet it was also very agile, outperforming the Comet tank in tests. The next Centurion model, Mk.2, featured a much thicker 118 mm front glacis armour and a thicker side armour. Production began for the Centurion Mk.2 in November 1945 for 800 tanks from Leyland Motors, Royal Ordnance Factories, and Vickers. The Mk.2 was put into service in the 5th Royal Tank Regiment in December 1946.

After the Centurion Mk.2 was put into service, Royal Ordnance developed the successor to the 17-pounder, the 84 mm 20-pounder. With this, the Centurion went through another upgrade to mount the 20-pounder. The 20 mm Polsten gun was removed and replaced by a BESA gun due to its questionable utility. The new upgrade, now the Centurion Mk 3, also featured an automatic stabilization system that improved firing accuracy while on the move. The tank was first produced in 1948 and overtook the previous Mk.1 and Mk.2 in service. However, the 20-pounder also did not stay in service for long and were replaced by the more powerful 105 mm L7 gun from Royal Ordnance Factories. All Centurions versions after Mark 5/2 used the L7 gun, including the Centurion Mk 10, which also featured additional armour with the new gun.

Swedish import

Sweden, a neutral power during World War II, analyzed the progress of technology and concluded they needed a replacement tank for their armoured forces. The Swedish Armed Forces right after World War II in 1945 decided that the most suitable tank for the upcoming years of the Cold War was the Centurion tank. A request was sent for the purchase of the vehicles, but Britain affirmed that their needs must be met before any exports of the Centurion tank could be made. Not eager to wait long for their tanks, Sweden started development in 1951 to create their own tank, designated "Emil", as well as seek out the AMX-13 light tank from France. However the wait ended abruptly when Britain started to export the Centurion in 1952, and Sweden swooped up an order of 80 Centurion Mk 3 in 1952, with the first delivery arriving in April 1953. The Swedish designated the adopted Centurion Mk 3 tank as the Stridsvagn 81. In 1955, Sweden imported another batch of Centurion, 160 Mk 5 variants, and employed them in the same designation as well. In the 1960, Sweden bought another batch of Mk 10 tanks that were accepted as the Stridsvagn 101. During the years in service, the Strv 81 and 101 were upgraded with newer equipments, modules, and armaments, as well as changing the designation to signal the improvements. There were also tests such as the inclusion of SS.11 missile on the turret side to improve the firepower of the Centurions.

The Centurion Stridsvagn series served alongside the domestic Strv 103 design as the primary vehicle of the Swedish armoured forces. In 1990s, the Swedish military started to phase out the two tanks as they modernized their forces. After a series of tests between the Russian T-72, American M1 Abrams, and German Leopard 2, the Swedish military replaced their outdated armoured fleet with the Leopard 2, designated the Stridsvagn 121.

Media

War Thunder Wiki:
Premium Vehicles Strv-81

See also

Links to the articles on the War Thunder Wiki that you think will be useful for the reader, for example:

• reference to the series of the vehicles;
• links to approximate analogues of other nations and research trees.

External links

• [Devblog] Strv-81: The Missile Centurion