Report (May 1958) from the 2nd Equipment Planning Study Group

Original title: Rapport maj 1958 från studiegrupp 2 för fortsatt tygmaterielplanering

The 2nd study group for further equipment planning was responsible for figuring out what kind of requirements would be reasonable to expect from next-generation direct-fire AFV’s (tanks and APC’s, mostly) that were to enter service around 1965. In order to do this, the group considered what the Soviets were doing, what everyone else was doing, current bleeding edge research, where tank development was right now and where it was heading. In May of 1958 the group issued this report, which is a bit over 90 pages long.

The report discusses current trends in tank development, and designates three general lines of development called the A-tank, the T-tank and the S-tank.

  • The A-tank (A for America, probably) is the expected result from current US and UK design philosophy. It weighs about 40-45 metric tons and is frontally protected against sub-caliber kinetic penetrators fired from guns of up to 120 mm caliber, with mobility somewhat impaired by its weight. (In reality, this alternative later resulted in the M60 Patton and the Chieftain.)
  • The T-tank (T for Tyskland – Germany) is the expected result from current German and French design philosophy. It weighs about 30-35 metric tons and has very high specific engine power (25-30 hp/t or more), but only has frontal protection against (the equivalent of) 57 mm guns. (In reality, this alternative later resulted the Leopard 1 and the AMX-30.)
  • The S-tank (S for Sweden) is a proposed turretless Swedish design that has the same protection as the A-tank against kinetic weapons, while weighing only about 30 metric tons. Additionally, since the gun is fixed in the chassis, it can be fitted with screens or lattices that will protect it from all currently known anti-tank missiles and other HEAT penetrators.

The report then goes on to reason about the importance of low tank weight with regards to strategic mobility. For Swedish conditions, tanks should ideally weigh less than 37 metric tons. Based on this and other factors, the authors argue that the army should not purchase upgunned Centurions from the UK, as they are too heavy and an insufficient upgrade over the 84 mm variant. Instead, it is recommended that future Swedish tank development should focus on a) testing the S-tank concept in practice to see if it’s a workable solution, b) start development on a domestic A-tank equivalent (reusing the existing Krv chassis for experiments as necessary), using an autoloader instead of a manual loader to keep the weight down, and c) keep an eye on developments in the US and UK with the intention of purchasing complete tanks if something better/cheaper than the domestic alternatives comes up.

The report also features about a metric ton of appendices, which I have photographed but not published here because they are mainly used as support for the recommendations outlined in the main report and thus not really all that interesting on their own. If you see one you want in the table of contents, leave a comment and ask for it and I’ll post it.

Archive reference: SE/KrA/0266/002/01:H/F III/1

Minutes of meetings with the armor committee of 1941

The “armor committee of 1941” (1941 års pansarkommitté) was a working group tasked to develop a satisfactory Swedish medium tank, with severe time constraints and a strict requirement that it must not weigh more than 22 tons. The result was strv m/42, which basically was an improved Landsverk L-60.

These four documents contain minutes of meetings with the committee in 1941 and 1942.

Archive reference: SE/KrA/0062/D/01/016:H/F I/1 a

Memo regarding considerations for series production of akv 151 (KV 155)

Original title: PM rörande akv 151, överarbetning av konstruktionen med hänsyn till planerad tillverkning i serie

This memo (dated 1960-01-04) discusses series production of the akv 151 SPG (aka. KV 155, the bkan 1 prototype) and some of the project history. The author notes that since the original suggestion in the second quarter of 1949, eleven years have passed and series production has not yet started. A number of reasons for this is mentioned (lack of engineers, changes in the specification, doubts whether the project is viable at all). The author concludes that because of the changes in the specification and the fact that the current prototype is based on a chassis (the Krv) that is not likely to be mass produced, the vehicle (and its chassis in particular) will need to be reworked before it can enter series production.

The author also mentions that it would be desirable to reduce the weight of the vehicle; the prototype weighs 45 metric tons but according to a 1958 report Swedish AFV’s should weigh no more than 37 metric tons, and if possible weigh less than 25 tons. A note in the margin exclaims “-18% !” in red next to this paragraph; someone who read the memo probably doubts that this is possible (and they would be right, because the series production version turned out to weigh 52 metric tons in the end).

Finally, four alternatives are presented; two conventional and two using the suspension to help with gun elevation. The weight for all four alternatives is claimed to be less than 37 tons, which seems like a pipe dream in retrospect. Rough drawings of the alternatives are attached.

Archive reference: SE/KrA/0266/002/01:H/F I/43

Objectives for the 105mm tracked SPG project

Three documents regarding the 105mm tracked SPG project.

The first document (original title: Målsättning för 10,5 cm haubits i bandlavett) is a letter from the Commander of the Army to the Weapons Bureau at KATF, dated 1959-06-25, in which the objectives for the 105mm tracked SPG project are laid out. The letter recognizes that much regarding the construction of the SPG is still undecided and asks KATF to present a few main alternatives that are to be considered in a final decision, and that this presentation should be completed no later than September 15th, 1959.

The second document (original title: VPM ang projektering och konstruktion av 10,5 cm bandhaub) is a memo from the 1st Weapons Bureau, discussing some of the main alternatives available for the project and requesting that the 2nd Weapons Bureau and the Vehicle Bureau respond to the memo with their opinions.

The third document (original title: Yttrande över “VPM ang projektering och konstruktion av 10,5 cm bandhaub”) is the Vehicle Bureau’s response to the second document.

Archive reference: SE/KrA/0266/002/01:H/F I/30

Aberdeen Proving Grounds test report for an AMX-13 prototype

A report in English from the Aberdeen Proving Grounds, covering their initial evaluation of what seems to be an AMX-13 prototype (the report just calls it “French light tank”). Original project number is TT 2-674.

The report seems to have wandered a long and winding road to end up in the archive where I found it. It’s originally dated 1951-02-17, and mentions that the testing was done in October to December of 1950. Somehow, it then ends up in the Top Secret (“kvalificerat hemligt”, of particular importance to the safety of the realm, cannot be shown to anyone without the approval of the head of the Department of Defense) archive of the Swedish Royal Army Ordnance Administration, the Vehicle Bureau, in late November of 1951. It sits there for a few years until it’s eventually downgraded to “regular” secret and discussed at the Vehicle Bureau in October of 1958, and that’s where I found it.

The photo appendices are sadly of a very bad quality; they seem to have copied them using some arcane machine that gave terrible quality. Appendices D, E and G are missing, either because they were illegible because of said copying machine, or because they weren’t included in the archive.

Archive reference: SE/KrA/0266/002/01:H/F I/19

Memo regarding Centurion turrets on the Krv chassis

A memo dated 1959-06-12 regarding the possibility of putting a Centurion mk 10 turret on the Krv chassis. Some modifications are required of either the chassis itself or the turret, and a turret blueprint with some handwritten notes on it is attached.

Archive reference: SE/KrA/0266/002/01:H/F I/32

Memo regarding the future development of turreted tanks (1959)

A memo dated 1959-03-23, outlining the guidelines for future development of turreted tanks. The “A-tank” (the conventional turreted alternative to the S-tank, developed in case the hydraulic gun laying system on the S-tank would prove unworkable) is put on hold (and thus effectively cancelled, since the army ended up choosing the S-tank) and possibilities for putting a Centurion mk 10 turret on the Krv chassis is discussed. The latter is proposed as an alternative to purchasing the Centurion mk 10 mainly for economical and trade balance reasons, since it would mean building the tank in Sweden rather than purchasing it from the UK.

Archive reference: SE/KrA/0266/002/01:H/F I/32

Discussion and schematics of autoloaders for Strv A and Strv S

Three documents dated in January and February of 1959, discussing autoloader mechanisms for the two projected tank options of the time, the S-tank and the A-tank (the latter being a turreted tank of conventional design, cancelled at an early stage in favor of the S-tank).

Archive reference: SE/KrA/0266/002/01:H/F I/33

Evaluation of later mark Centurion tanks, 1958

Two travel reports from delegations sent to the UK in September and October of 1958 with the intent of evaluating the improvements done by the British in their later mark Centurion tanks (mk 7-10). Lots of interesting reading in general, revealing how the Swedish and the British armies of the time thought about their tanks.

Archive reference: SE/KrA/0266/002/01:H/F I/19

105 mm tracked SPG project, contract and technical specification

An agreement (dated 1960-03-22) between KATF and Bofors, authorizing the latter to complete certain development work on a 105mm tracked SPG. As an appendix to the agreement is a rough technical specification for the SPG; this is the interesting part.

Archive reference: SE/KrA/0266/002/01:H/F I/40