Monthly Archives: December 2013

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

Report on live fire trials against a strv 74 turret

A report from the Royal Military Academy, dated 1960-11-30, regarding live fire trials conducted against a strv 74 turret in August of 1960.

Weapons used:

  • 20 mm “tube cannon” for strv 74 (a smaller gun barrel inserted into the full-size one for practice purposes), firing 20 mm spårljuspansarprojektil m/42 (a full-caliber AP tracer round)
  • 37 mm anti-tank gun m/34 firing 37 mm spårljuspansarprojektil m/49 (a sub-caliber AP tracer round with a 24 mm penetrator)
  • 75 mm tank gun for strv 74, firing 7,5 cm spårljuspansarprojektil m/49 (a sub-caliber AP tracer round with a 50 mm penetrator)

The report concludes that the 20 mm rounds will reliably penetrate the turret side at distances less than 300 meters, with possible penetrations up to 670 meters. The 37 mm sub-caliber rounds will reliably penetrate most of the turret except an area within 20 degrees to either side of the gun barrel at distances under 750 meters, and may be able to penetrate the gun mantlet at distances up to about 850 meters. The 75 mm sub-caliber rounds will reliably penetrate the gun mantlet with considerable behind-armor effects at distances up to at least 1400 meters and most likely significantly longer distances as well, but that has not been tested.

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

Summary of penetration data for various projectiles (1958)

Original title: Sammanställning av data för genomslag av pansar
Author: Ann Littke-Persson, research engineer 1st class

A research report from FOA 2 (defense research agency, bureau 2), dated 1958-08-01, regarding the penetration capabilities of various projectiles of different kinds. The report is mainly theoretical in nature, but it extrapolates values for planned projectiles from empirical data obtained from various test firings, both Swedish and foreign.

Page 36 has a convenient reference of terms used in the report.

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

Preliminary plans for guns, autoloaders and ammunition for strv A and strv S

Two documents from 1958 describing early developments in tank gun specifications, intended for two alternatives for a future Swedish tank. The alternatives are called “stridsvagn typ A” and “stridsvagn typ S” where A is a conventional turreted design and S is a very early S-tank (at this point they haven’t yet decided if the S-tank’s hydraulic gun laying system is technically feasible or not, so they plan for both alternatives).

Archive reference: SE/KrA/0266/002/01:H/F I/20