Strv 103 (Family)
The Stridsvagn 103 (Strv 103), also known as the "S-Tank", is a Swedish post-World War II main battle tank, designed and manufactured in Sweden by Bofors AB (and to some extent Landsverk AB). It was developed in the late 1950s to the mid 1960s and was the first main battle tank to use a turbine engine, as well as the first, and so far only, service tank to not feature a turret. While some might argue that the S-Tank is not a tank, or that turretless casemate vehicles can be called tanks, it is a fact that the S-Tank was designed as, deployed as and used as a tank by the Swedish army. Besides lacking a turret it was however the first tank with a fixed main gun, meaning that the gun was fixed in the hull on both the X-axis and Y-axis. To aim the gun horizontally the entire vehicle had to be steered side to side (same as the hull gun on the B1 bis). To aim vertically the tank used a new type of controllable suspension, probably also a first in the world, that allowed the tank to tilt forwards and backwards using gas-hydraulic hydropneumatics.
The name "S-Tank" is not an English nickname for the tank, but actually a translation of the Swedish name "Stridsvagn S". Stridsvagn S was the name given to the design during its development and it also became the product name for it after development had finished. The "S" in the name S-Tank refers to Sweden (Sverige) and it was one of three base-designs that competed against each other to become Sweden's next generation MBT during the mid to late 1950s. The other two base-designs were called "A-Tank" (Stridsvagn A) and "T-Tank" (Stridsvagn T). The A-Tank (Amerika / America) was a turreted heavily armored MBT that followed the design principles of the Americans and British (such as the M48 Patton and Centurion), while the T-Tank (Tyskland / Germany) was a turreted lightly armoured MBT that followed the design-principles of the Germans and the French (such as the Leopard 1 and AMX-30).
Strv 103-0 is the prototype series before the head series with Strv 103A got delivered to the Swedish army. After the trial of the two trial vehicles S1 and S2 in 1961, Sweden ordered 10 pre-series Strv 103 which would become the 0-series.
By 1967 the Strv 103A had started to be delivered to the army, a total of 70 Strv 103As were ordered by the army as the first series production. Strv 103A had a 300hk powered gas turbine that during delivery proved to be not quite effective and would be required a change in the upcoming version of the Strv 103. Directly when the S tank got delivered instructor courses began and it was not until 1968 that the first conscripts go the education on the Strv 103 "S" systems.
Strv 103C is the last official series of the S tank, in the army decision 1972 and 1982 it was decided that getting a new tank for the army was going to be postponed to the 1990s and the Swedish army at time would focus on lighter combat vehicles. So to modernize the S tanks the Strv 103Bs had to go through a renovation with upgrading the systems and improving the vehicles in a so called REMO (Renovation and Modification) process. It was not until 1986 the first Strv 103B got its REMO done and was designated Strv 103C.