One of the most remarkable tanks to see service in any of the world’s armies since the end of World War 2, the Stridsvagn 103 was designed by Sven Berge of the Swedish Army as an alternative to the KRV heavy tank being developed by a consortium of Landsverk, Volvo and Bofors.
Conceived in 1956 the intention behind the Stridsvagn was to make the tank easier to conceal on the battlefield by reducing its overall height through eliminating the need for a complicated rotating turret to hold the main armament. Instead the gun was to be fix mounted in the chassis and would be aimed by moving the entire vehicle (this was not an original idea-the earliest Christie tanks of the 1920s had been designed in a rather similar manner). Elevation would be by raising or lowering the hydro-pneumatic suspension, whilst final aiming adjustment would be done with fine servo motors.
Test Rigs proved that the concept was indeed possible, and in 1958 Bofors was awarded a contract to build two prototypes which were completed in 1961. So sure was the Swedish Army that the project was sound that, in 1960, an order was placed for ten pre-production vehicles. Full production of the Stridsvagn commenced in 1966, the production models differing from the prototypes only in minor details, and continued until 1971 by which time some 300 vehicles had been built for the Swedish Army. Remarkably the development costs had only been some £9 million.
The main armament selected for the Stridsvagn 103 was the British rifled 105mm L7 automatically loaded from a 50-round magazine located in the rear hull. This gun is capable of firing at a maximum rate of 15 rounds per minute, and a typical ammunition load might consist of 25 rounds of APDS, 20 rounds of High Explosive, and 5 of smoke. A drawback with the Stridsvegn was that the gun was unstabilised which meant that the gun could be only really effective if fired when the tank was stationary. In addition, the need to power the servo motors requires that the engine be kept running for the entire time that the tank is in action.
Another unique feature of the Stridsvagn 103 is that it had two powerplants. A Rolls Royce K60, multi-fuel engine for normal road use, and a Boeing 553 gas-turbine for additional power when in combat or when moving across country where a higher power to rate ratio is required.. The Rolls Royce develops 240 bhp at 3650 rpm on diesel fuel, whilst the Boeing could produce 490 bhp at 38,000 rpm. Despite the rather low (for a 40-ton tank) powered engine the Stridsvagn is still capable of reaching a maximum speed of 50 kph (31 mph) with a range of 390 km (242 miles).
Unlike most modern tanks the Stridsvagn had a crew of only three members. The driver sat on the left of the hull and was equipped with a combined periscope and binocular sight so that he could also act as an observer. The Commander sat to his right with an identical sight but was also responsible for aiming and firing the gun. The Radio Operator was seated facing rearward in the hull had duplicate driving controls so that he could act as driver when the tank was in reverse. The three crew arrangement is usually not very popular in other NATO Armies as it generally means extra work for the tank's crew with routine maintenance and other duties.
From the S103B model the Stridsvagn was made fully amphibious, having a floatation screen on top of the hull that could be erected in 20 minutes. The tank is propelled through the water by its tracks at a speed of 6 km/hr (3.7 mph). In addition this tank was given space armour, Night driving and fighting aids, and fitted as standard with a dozer blade under the nose of the tank with which it could prepare its own defensive positions-a very useful addition as the Swedish army strategy is more inclined to defensive rather than offensive operations.
The S103C model entering service in 1986 incorporated the Improved Fire Control system (IFC), in the 1987/88 upgrade this model replaced the original Rolls Royce Diesel with the 290hp Detroit Diesel model 6V-53T a modified Volvo transmission; a laser range-finder and additional fuel tanks. In 1989 full NBC protection was incorporated. In 1991 some consideration was given to adding the Explosive Reactive Armour (ERA) though it is not clear whether or not this was ever fitted to service vehicles.
Although there were no specialist vehicles built on the S103 chassis a number of components were used in the construction of the Bofors Bandkanon 155mm self-propelled artillery system which again was only used by the Swedish Army.
The sophistication of the S-tank however made it just as expensive to build as a conventional turreted tank which resulted in no orders being received outside that of the Swedish Army. In 1997, Sweden began to re-equip with Leopard 2 to replace theCenturions and Stridsvagn which had been its tank force for a good many years.