Stridsvagn 103
Encyclopedia
The Stridsvagn 103 or S-Tank ("Stridsvagn" being the Swedish word for Tank
, literally "fighting carriage"), was a Swedish
post-war main battle tank
. It was known for its unconventional turret
-less design, with a fixed gun traversed
by engaging the tracks
and elevated
by adjusting the hull suspension
. The S-Tank was developed in the 1950s and was the first main battle tank
to use a turbine
engine. The result was a very low-profile design with an emphasis on defense
and heightened crew protection level. S-Tanks formed a major portion of the Swedish armored forces from the 1960s to part of the 1990s, but have since been removed from service in favour of the Leopard 2
.
s. A consortium of Landsverk
, Volvo
and Bofors
responded with a new heavy tank design, known under the codename KRV, fitted with a 155 mm smoothbore gun in an oscillating turret
. However this would be an expensive option and the Army started looking at British, German and American tanks.
Then, in 1956, Sven Berge of the Swedish Arms Administration proposed Alternativ S, a domestic alternative (S standing for Swedish). Noting that the risk of being hit in combat was strongly related to height, he proposed that any new design should be as low as possible. The only practical way to do this was to eliminate the turret (which would also make the tank much lighter and simpler), though in terms of absolute height, this still did not give the Strv 103 any significant advantage. Its most likely opponent, the T-72
, was only 2.23 meters in height with its turret versus the 2.14 meters of the Strv 103 (a mere 3.5 inches shorter). However, tanks occasionally deploy themselves into hull-down
firing positions, either purpose dug or using the crest of a hill, in order to reduce the exposure of the vehicle to enemy fire. In this firing position the level of exposure is determined by the distance between the bottom of the gun barrel to the top of the turret or vehicle, and the angle to which the vehicle is able to depress the gun barrel. Since the Strv 103 orients the entire tank to depress and elevate the barrel, in a hull down position it has a very low apparent height and subsequent visual profile to the enemy. It could also lower the hull a further 13 cm by adjustment of the suspension. The static use of a tank is at odds with the very concept of a tank, i.e., a mobile, protected gun platform able to bring heavy firepower to bear upon the enemy while attacking. Hence the S-Tank must be considered a strictly defensive vehicle.
Berge's design tried to solve the aiming problem through the use of a fully automated transmission and suspension system, which would turn and tilt the tank under the gunner's control. The gun itself would be fixed to the hull. Unfortunately, this made it impossible to use a stabilized gun. As a result, the tank could not accurately move and fire at the same time. However, during the period the S-tank was in service, turreted tanks rarely fired on the move, and especially not when used defensively.
Other features of the tank were also quite radical. The gun, a Bofors 105mm L/62, able to use the same ammunition as the British 105 mm L7
, would be equipped with an autoloader, allowing the crew to be reduced to two - most designs of the era used a crew of four - gunner/driver and commander. Room was available for an extra crew member, the rear driver, who faced the rear of the tank equipped with a complete setup for driving. This allowed the tank to be driven backwards at the same speed as forwards, keeping its frontal armour pointed at the enemy.
The commander and gunner/driver both had the same set of sights and controls to fire the gun and drive the tank. Additionally the tank was powered by two engines, a 240 hp Rolls-Royce K60 opposed-piston diesel for cruising and manoeuvring the tank in aiming, and a 300 hp Boeing
502 turbine for dashing at high speed. This was the first use of a turbine engine in a production tank; the Soviet T-80
and US M1 Abrams
would later be built with gas turbines for main propulsion.
The concept was interesting enough that Bofors was asked to build a prototype of the suspension/drive train, which they completed successfully. In 1958 a follow-on contract called for two production prototypes, which were completed in 1961. By this point, the army was so satisfied with the design that an initial pre-production order of 10 was placed in 1960. With minor changes, the S-Tank was adopted as the Stridsvagn 103 (103 from the fact that it was the third tank accepted with a 10 cm gun). Full production started in 1967 and ended in 1971 with 290 delivered. The changes included a new gyrostabilised commander's cupola armed with a 7.62 mm KSP 58
machine gun, and upgraded frontal armour. A screen
, similar to those of the Panzer IV Ausf. J of World War Two, was available to help defeat HEAT
rounds; however, it was kept secret for many years and was only to be fitted in the event of war.
The Strv 103 was fully amphibious. A flotation screen could be erected around the upper hull in about 20 minutes, and the tracks would drive the tank at about 6 kilometres per hour (3.7 mph) in water.
One tank in each platoon was fitted with a blade under the front hull that allowed it to dig itself into the ground for added protection.
The Stridsvagn 103 never saw combat and so its design remains unproven. However, for its intended role in the 1960s it had numerous advantages. In 1967, Norway carried out a two week comparative observation test with the Leopard 1 and found that with closed hatches the 103 spotted more targets and fired faster than the Leopard. In April to September 1968, two 103s were tested at the British armour school in Bovington
, which reported that "the turretless concept of the "S"-tank holds considerable advantage over turreted tanks". In BAOR 1973, the 103 was tested against the Chieftain tank
. Availability never fell under 90% and the final report stated, "It has not been possible to prove any disadvantage in the "S" inability to fire on the move." In 1975, two 103s were tested at the American armour center at Fort Knox. The trial demonstrated the 103 fired more accurately than the M60A1E3, but on an average 0.5 seconds slower.
As the weight of the Strv 103 had increased compared to the pre-production tanks the 103 turned out to be underpowered. Hence a more powerful version of the same gas turbine, manufactured by Caterpillar
, was introduced after the first production run of 80 tanks. The early version was soon upgraded to B-standard.
with additional fuel tanks, and added a new laser rangefinder. There was some consideration of adding both reactive and/or appliqué armour in the early 1990s, but in the end the S-Tank was instead phased out of Swedish service in favour of the Leopard 2
, which entered service in 1997. The last year in which the S-Tank were used to train tank crews was 1997.
This prototype was used during the trials for the new main battle tank system for the Swedish armed forces alongside all the other tanks tested. For a few years this prototype was even tested under remote control. The only Strv 103D ever built is today on display at the Axvall armor museum, together with some 103C models. They are all still in running order.
Tank
A tank is a tracked, armoured fighting vehicle designed for front-line combat which combines operational mobility, tactical offensive, and defensive capabilities...
, literally "fighting carriage"), was a Swedish
Sweden
Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....
post-war main battle tank
Main battle tank
A main battle tank , also known as a battle tank or universal tank, is a tank that fills the heavy direct fire role of many modern armies. They were originally conceived to replace the light, medium, heavy and super-heavy tanks. Development was spurred onwards in the Cold War with the development...
. It was known for its unconventional turret
Gun turret
A gun turret is a weapon mount that protects the crew or mechanism of a projectile-firing weapon and at the same time lets the weapon be aimed and fired in many directions.The turret is also a rotating weapon platform...
-less design, with a fixed gun traversed
Gun laying
Gun laying is the process of aiming an artillery piece, such as a gun, howitzer or mortar on land or at sea against surface or air targets. It may be laying for direct fire, where the gun is aimed similarly to a rifle, or indirect fire, where firing data is calculated and applied to the sights...
by engaging the tracks
Caterpillar track
Continuous tracks or caterpillar tracks are a system of vehicle propulsion in which modular metal plates linked into a continuous band are driven by two or more wheels...
and elevated
Elevation (ballistics)
In ballistics, the elevation is the angle between the horizontal plane and the direction of the barrel of a gun, mortar or heavy artillery. Originally, elevation was a linear measure of how high the gunners had to physically lift the muzzle of a gun up from the gun carriage to hit targets at a...
by adjusting the hull suspension
Suspension (vehicle)
Suspension is the term given to the system of springs, shock absorbers and linkages that connects a vehicle to its wheels. Suspension systems serve a dual purpose — contributing to the car's roadholding/handling and braking for good active safety and driving pleasure, and keeping vehicle occupants...
. The S-Tank was developed in the 1950s and was the first main battle tank
Main battle tank
A main battle tank , also known as a battle tank or universal tank, is a tank that fills the heavy direct fire role of many modern armies. They were originally conceived to replace the light, medium, heavy and super-heavy tanks. Development was spurred onwards in the Cold War with the development...
to use a turbine
Turbine
A turbine is a rotary engine that extracts energy from a fluid flow and converts it into useful work.The simplest turbines have one moving part, a rotor assembly, which is a shaft or drum with blades attached. Moving fluid acts on the blades, or the blades react to the flow, so that they move and...
engine. The result was a very low-profile design with an emphasis on defense
Defense (military)
Defense has several uses in the sphere of military application.Personal defense implies measures taken by individual soldiers in protecting themselves whether by use of protective materials such as armor, or field construction of trenches or a bunker, or by using weapons that prevent the enemy...
and heightened crew protection level. S-Tanks formed a major portion of the Swedish armored forces from the 1960s to part of the 1990s, but have since been removed from service in favour of the Leopard 2
Leopard 2
The Leopard 2 is a main battle tank developed by Krauss-Maffei in the early 1970s for the West German Army. The tank first entered service in 1979 and succeeded the earlier Leopard 1 as the main battle tank of the German Army. Various versions have served in the armed forces of Germany and twelve...
.
History
In the mid-1950s the Swedish army put out a contract tender for a new tank design to replace their CenturionCenturion tank
The Centurion, introduced in 1945, was the primary British main battle tank of the post-World War II period. It was a successful tank design, with upgrades, for many decades...
s. A consortium of Landsverk
AB Landsverk
Landsverk was founded in 1872 as Firman Petterson & Ohlsen. It was a heavy industry, manufacturingrailroad cars, harbour cranes and agricultural machinery. It was located in Landskrona, Sweden.-Early days:...
, Volvo
Volvo
AB Volvo is a Swedish builder of commercial vehicles, including trucks, buses and construction equipment. Volvo also supplies marine and industrial drive systems, aerospace components and financial services...
and Bofors
Bofors
The name Bofors has been associated with the iron industry for more than 350 years.Located in Karlskoga, Sweden, the company originates from the hammer mill "Boofors" founded 1646. The modern corporate structure was created in 1873 with the foundation of Aktiebolaget Bofors-Gullspång...
responded with a new heavy tank design, known under the codename KRV, fitted with a 155 mm smoothbore gun in an oscillating turret
Oscillating turret
An oscillating turret is a form of turret for armoured fighting vehicles, both tanks and armoured cars. The turret is unusual in being made of two hinged parts. Both elevation and recoil rely on the upper part of the turret moving relative to the lower part....
. However this would be an expensive option and the Army started looking at British, German and American tanks.
Then, in 1956, Sven Berge of the Swedish Arms Administration proposed Alternativ S, a domestic alternative (S standing for Swedish). Noting that the risk of being hit in combat was strongly related to height, he proposed that any new design should be as low as possible. The only practical way to do this was to eliminate the turret (which would also make the tank much lighter and simpler), though in terms of absolute height, this still did not give the Strv 103 any significant advantage. Its most likely opponent, the T-72
T-72
The T-72 is a Soviet-designed main battle tank that entered production in 1970. It is developed directly from Obyekt-172, and shares parallel features with the T-64A...
, was only 2.23 meters in height with its turret versus the 2.14 meters of the Strv 103 (a mere 3.5 inches shorter). However, tanks occasionally deploy themselves into hull-down
Hull-down
The term hull-down describes the situation where the upper part of a vessel or vehicle is visible, but the main, lower body is not; the opposite term hull-up describes the situation where all of the body is visible....
firing positions, either purpose dug or using the crest of a hill, in order to reduce the exposure of the vehicle to enemy fire. In this firing position the level of exposure is determined by the distance between the bottom of the gun barrel to the top of the turret or vehicle, and the angle to which the vehicle is able to depress the gun barrel. Since the Strv 103 orients the entire tank to depress and elevate the barrel, in a hull down position it has a very low apparent height and subsequent visual profile to the enemy. It could also lower the hull a further 13 cm by adjustment of the suspension. The static use of a tank is at odds with the very concept of a tank, i.e., a mobile, protected gun platform able to bring heavy firepower to bear upon the enemy while attacking. Hence the S-Tank must be considered a strictly defensive vehicle.
Berge's design tried to solve the aiming problem through the use of a fully automated transmission and suspension system, which would turn and tilt the tank under the gunner's control. The gun itself would be fixed to the hull. Unfortunately, this made it impossible to use a stabilized gun. As a result, the tank could not accurately move and fire at the same time. However, during the period the S-tank was in service, turreted tanks rarely fired on the move, and especially not when used defensively.
Other features of the tank were also quite radical. The gun, a Bofors 105mm L/62, able to use the same ammunition as the British 105 mm L7
Royal Ordnance L7
The Royal Ordnance L7 is the basic model of Britain's most successful tank gun. The L7 was a 105 mm L/52 rifled design intended for use in armoured fighting vehicles...
, would be equipped with an autoloader, allowing the crew to be reduced to two - most designs of the era used a crew of four - gunner/driver and commander. Room was available for an extra crew member, the rear driver, who faced the rear of the tank equipped with a complete setup for driving. This allowed the tank to be driven backwards at the same speed as forwards, keeping its frontal armour pointed at the enemy.
The commander and gunner/driver both had the same set of sights and controls to fire the gun and drive the tank. Additionally the tank was powered by two engines, a 240 hp Rolls-Royce K60 opposed-piston diesel for cruising and manoeuvring the tank in aiming, and a 300 hp Boeing
Boeing
The Boeing Company is an American multinational aerospace and defense corporation, founded in 1916 by William E. Boeing in Seattle, Washington. Boeing has expanded over the years, merging with McDonnell Douglas in 1997. Boeing Corporate headquarters has been in Chicago, Illinois since 2001...
502 turbine for dashing at high speed. This was the first use of a turbine engine in a production tank; the Soviet T-80
T-80
The T-80 is a main battle tank designed and manufactured in the former Soviet Union. A development of the T-64, it entered service in 1976 and was the first production tank to be equipped with a gas turbine engine for main propulsion.the Swedish Stridsvagn 103 of 1971 used a gas turbine alongside...
and US M1 Abrams
M1 Abrams
The M1 Abrams is a third-generation main battle tank produced in the United States. It is named after General Creighton Abrams, former Army Chief of Staff and Commander of US military forces in Vietnam from 1968 to 1972. The M1 is a well armed, heavily armored, and highly mobile tank designed for...
would later be built with gas turbines for main propulsion.
The concept was interesting enough that Bofors was asked to build a prototype of the suspension/drive train, which they completed successfully. In 1958 a follow-on contract called for two production prototypes, which were completed in 1961. By this point, the army was so satisfied with the design that an initial pre-production order of 10 was placed in 1960. With minor changes, the S-Tank was adopted as the Stridsvagn 103 (103 from the fact that it was the third tank accepted with a 10 cm gun). Full production started in 1967 and ended in 1971 with 290 delivered. The changes included a new gyrostabilised commander's cupola armed with a 7.62 mm KSP 58
FN MAG
The FN MAG is a Belgian 7.62 mm general-purpose machine gun, designed in the early 1950s at Fabrique Nationale by Ernest Vervier. It has been used by more than 80 countries, and it has been made under licence in countries such as Argentina, Egypt, India, Singapore, the United Kingdom and the...
machine gun, and upgraded frontal armour. A screen
Spaced armour
Armour with two or more plates spaced a distance apart is called spaced armour. When sloped it reduces the penetrating power of bullets and solid shot as after penetrating each plate they tend to tumble, deflect, deform, or disintegrate; when not sloped it increases the protection offered by the...
, similar to those of the Panzer IV Ausf. J of World War Two, was available to help defeat HEAT
Heat
In physics and thermodynamics, heat is energy transferred from one body, region, or thermodynamic system to another due to thermal contact or thermal radiation when the systems are at different temperatures. It is often described as one of the fundamental processes of energy transfer between...
rounds; however, it was kept secret for many years and was only to be fitted in the event of war.
The Strv 103 was fully amphibious. A flotation screen could be erected around the upper hull in about 20 minutes, and the tracks would drive the tank at about 6 kilometres per hour (3.7 mph) in water.
One tank in each platoon was fitted with a blade under the front hull that allowed it to dig itself into the ground for added protection.
The Stridsvagn 103 never saw combat and so its design remains unproven. However, for its intended role in the 1960s it had numerous advantages. In 1967, Norway carried out a two week comparative observation test with the Leopard 1 and found that with closed hatches the 103 spotted more targets and fired faster than the Leopard. In April to September 1968, two 103s were tested at the British armour school in Bovington
Bovington Camp
Bovington Camp is a British Army base in Dorset, England.It is home to The Armour Centre, formerly the Royal Armoured Corps Centre and includes Allenby Barracks and Stanley Barracks. Bovington Tank Museum is adjoining....
, which reported that "the turretless concept of the "S"-tank holds considerable advantage over turreted tanks". In BAOR 1973, the 103 was tested against the Chieftain tank
Chieftain tank
The FV 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...
. Availability never fell under 90% and the final report stated, "It has not been possible to prove any disadvantage in the "S" inability to fire on the move." In 1975, two 103s were tested at the American armour center at Fort Knox. The trial demonstrated the 103 fired more accurately than the M60A1E3, but on an average 0.5 seconds slower.
Strv 103B
Caterpillar Inc.
Caterpillar Inc. , also known as "CAT", designs, manufactures, markets and sells machinery and engines and sells financial products and insurance to customers via a worldwide dealer network. Caterpillar is the world's largest manufacturer of construction and mining equipment, diesel and natural gas...
, was introduced after the first production run of 80 tanks. The early version was soon upgraded to B-standard.
Strv 103C
An upgrade program was started in 1986 to fit all vehicles with improved fire control systems. Also, each S-Tank was fitted with a dozer blade, rather than just one per platoon. A further upgrade in 1987/88 replaced the Rolls-Royce engine with a newer 290 hp (216 kW) Detroit DieselDetroit Diesel
As a corporation, Daimler Trucks North America has decided to rename the company "DETROIT".Detroit Diesel Corporation is an American-based diesel engine producer headquartered in Detroit, Michigan, USA...
with additional fuel tanks, and added a new laser rangefinder. There was some consideration of adding both reactive and/or appliqué armour in the early 1990s, but in the end the S-Tank was instead phased out of Swedish service in favour of the Leopard 2
Leopard 2
The Leopard 2 is a main battle tank developed by Krauss-Maffei in the early 1970s for the West German Army. The tank first entered service in 1979 and succeeded the earlier Leopard 1 as the main battle tank of the German Army. Various versions have served in the armed forces of Germany and twelve...
, which entered service in 1997. The last year in which the S-Tank were used to train tank crews was 1997.
Strv 103D
In the mid-1990s, as the Swedish armed forces were looking for a new main battle tank, one Strv 103C was upgraded into the Strv 103D. The major changes were the installation of fire-control computer, thermal viewers for both the gunner and the commander, allowing the crew to fight at night-time and in bad weather conditions, and the installation of passive light enhancers for driving. Some minor changes to the suspension system and engine were also made.This prototype was used during the trials for the new main battle tank system for the Swedish armed forces alongside all the other tanks tested. For a few years this prototype was even tested under remote control. The only Strv 103D ever built is today on display at the Axvall armor museum, together with some 103C models. They are all still in running order.
External links
- Society S-tank - Föreningen stridsvagn S - Official site
- Society S-tank- Welcome to The S tank association-Official site