Monthly Archives: February 2014
Future development study by the armor committee of 1946
This study (dated 1946-07-02) presents what the armor committee of 1946 thinks future Swedish tank developments should focus on, in light of foreign developments, current technical limitations, requirements and desires from the army headquarters and various other factors. The study is about 50 pages long plus seven appendices, not all of which are present here.
The committee finds that research should focus on:
- raising the muzzle velocity of current anti-tank guns above 900 m/s
- improving current AP rounds so that they don’t shatter at impact velocities over 900 m/s, possibly by using a core of a harder material
- finding a way to make HEAT rounds work at high impact velocities
- developing an effective protection against HEAT rounds
- studying the actual damage effects of HEAT rounds
Further, it recommends that development should start on:
A) a tank, preferably no heavier than 25 tons, armed with either a 7,5 cm or a 10,5 cm gun, with a specific engine power of about 20 hp/ton and protected frontally against guns of up to 57 mm caliber at 400 meters.
B) a tank destroyer, no heavier than 30 tons, armed with either 10,5 cm kan m/34 or 10,5 cm lvkan m/42, with a specific engine power of about 17 hp/ton and frontal protection against guns of up to 7,5 cm caliber at 800 meters.
Finally, it also discusses re-use of older tanks, such as rebuilding strv m/41 into a TD with a 7,5 cm gun.
Archive reference: SE/KrA/0062/D/01/025:H/F I/8
TK 105-9 construction program
This letter (dated 1952-09-27) from Bofors to KAFT describes a proposed construction program for a 105 mm L/67 rifled tank gun, fed by two 7-round autoloader drums and placed in a heavily armored turret intended to be mounted in a 35-ton tank currently being under development at KAFT (project EMIL, of course). The letter mentions that 12 and 15 cm L/40 smoothbore guns are also possible alternatives but no further details are provided. There’s a list of blueprints for these guns but they are (as usual) missing from the archives because apparently the bureaucrats at the time hated historians.
Archive reference: SE/KrA/0062/D/01/016:H/F I/28
Akv 1949 prototype construction program
These two documents, originating at Bofors in March and December of 1952 respectively, describe the plans for developing a working prototype of the 15 cm self-propelled artillery piece that was originally proposed in 1949, variously called 15 cm kv fm/49, akv 1949 and VK 152 S 49 (the latter being the internal Bofors designation). Initially, three alternatives for the track assembly and drive train are proposed: one using the existing drive train from the strv m/42 (Volvo A8B engine uprated to 450 HP and VL 420 gearbox), one a purely experimental project based on a Sherman’s gearbox and drive train, and one possible “merge” with the drive train and gearbox of a future tank being developed by KAFT (which is obviously project EMIL, but it was very much a paper project at this point).
The decision described in these documents is to go with the strv m/42 option, but this must’ve been changed to the third alternative at some point because eventually what ended up happening was that the project EMIL chassis and engine were used.
Archive reference: SE/KrA/0062/D/01/016:H/F I/28
Delivery specification for ikv 72
This is a delivery specification/data sheet for ikv 72 (known as “tankett m/49” during its development). Includes an armor scheme – not that the armor is of any significant thickness, only intended to protect against regular rifle-caliber rounds.
Archive reference: SE/KrA/0062/D/01/016:H/F I/28
Rebuilding strv m/41 into a TD
This document (dated 1951-01-20) discusses different possible way of rebuilding obsolete strv m/41 (license-built Czech TNH) into a tank destroyer armed with a modified 7,5 cm lvkan m/37 AA gun, which has very similar ballistics to the regular 7,5 cm pvkan m/43. Both turreted and fixed gun installations are discussed.
Archive reference: SE/KrA/0062/D/01/016:H/F I/24
The beginnings of project EMIL
I’ve previously posted about project EMIL here; more specifically, a complete project summary with contents from various times during the project’s life. These 1951 documents however mark the very start of the project, suggesting that KAFT put six people to work for about a year in order to develop the project a loose idea to reasonably complete plans for a tank. There’s nothing new specs-wise here, just some project history.
Archive reference: SE/KrA/0062/D/01/016:H/F I/24
Minutes of meeting at Bofors 1951-05-30
Minutes of a meeting held at Bofors on May 30th and 31st 1951, regarding current projects. Most interestingly, a “new tank gun” is discussed, with some different alternatives presented.
Archive reference: SE/KrA/0062/D/01/016:H/F I/24
Report on current anti-tank weapons and development trends (1951)
This FOA report (dated 1951-01-23) summarizes the current state of anti-tank weaponry in the world, as well as current development trends. It contains some discussion on whether future anti-tank weapons should be based on kinetic projectiles or HEAT, and finds that in either case, the current Swedish anti-tank weapons are completely insufficient to fight current Russian tanks.
Contains penetration data for number of Swedish weapons (such as 37 mm pvkan m/37, 57 mm pvkan m/43, 7,5 cm strvkan m/41 and 7,5 cm pvkan m/43).
Archive reference: SE/KrA/0062/D/01/016:H/F I/24
Suggestion for a tracked mortar carrier (1950)
In 1950, a lieutenant at I 15, B. Schmidt, suggested to KAFT that in light of recent developments in the field of artillery-hunting radar it might be a good idea to mount the ubiquitous 12 cm Tampella mortar on a tracked chassis, enabling it to “shoot-and-scoot”.
This post features the lieutenant’s letter as well as a KAFT memo suggesting to try the idea out on the “tankette” chassis. As far as I know the idea was tried in reality but the mortar recoil turned out to be too big for the small chassis and the idea was dropped.
Archive reference: SE/KrA/0062/D/01/016:H/F I/19
Discussions regarding AT super-weapons
In 1950 it was becoming alarmingly apparent that current Swedish AT weapons were completely inadequate for fighting foreign top-of-the-line tanks. A series of discussions were thus held at KAFT in order to figure out what kind of “anti-tank super-weapons” the army should be equipped with in the future. Since kinetic weapons were seen as impractically bulky and heavy, HEAT was considered the main alternative despite its downsides (such as difficulties with spaced armor).
Archive reference: SE/KrA/0062/D/01/016:H/F I/19