Monthly Archives: February 2014

Light tank development program 1949-1950

In March 1949 the army headquarters described the requirements for future AFV’s in a brief memo sent to KAFT. One of the vehicles called for was an unassuming 20-ton vehicle intended for infantry support, armed with a 75 or 105 mm gun. During 1949 and 1950 this vehicle was occasionally discussed, but left on the back burner in favor of the ongoing “tankette” development program. In August 1950 the army headquarters revisited the project and seems to have noticed certain alarming developments abroad; more specifically, tanks were rapidly becoming much bigger and heavier and with much greater protection.

As far as I know this project never led anywhere except to trials of the AMX-13, but it still gives some insight on what the army headquarters were thinking about tanks at the time. The sudden realization in late 1950 that foreign developments were just about immune to current Swedish tanks probably contributed to getting the EMIL project going the following year.

The documents are ordered chronologically.

Archive references: SE/KrA/0062/D/01/016:H/F I/16, SE/KrA/0062/D/01/016:H/F I/17 and SE/KrA/0062/D/01/016:H/F I/19

Further documents regarding tankette m/49

A few more documents from 1949 discussing tankett m/49, from a different archive volume than the previous post.

Archive reference: SE/KrA/0062/D/01/025:H/F I/2

Development of tankett m/49

These documents from 1949 (I’ve attempted to order them chronologically) describe the early stages of development of tankett m/49, a very cheap and light construction (intended for about 6.5 metric tons) originally envisioned in three versions: one with only machine guns, one with a tank gun (initially 75 mm) and one “special” that could be armed with things like flamethrowers. The development work was contracted to Landsverk (chassis), Bofors (gun) and Volvo (engine and drive train).

Initially the “gun tankette” was armed with the short 75 mm gun used on the strv m/42, but as the project progressed both a 84 mm and a 105 mm gun option were investigated. Eventually the vehicle would enter service as ikv 72, where ikv stands for “infanterikanonvagn”, which translates to something like “infantry gun carriage”.

Archive reference: SE/KrA/0062/D/01/016:H/F I/17 and SE/KrA/0062/D/01/016:H/F I/18

Memo regarding ammunition and caliber for new TD’s

This memo (dated 1949-05-01) discusses pros and cons with sub-caliber APCR rounds, in particular with regards to the armament of new tank destroyers. The difference between squeeze-bore and sub-caliber sabot rounds are briefly discussed, with sub-caliber sabot rounds being considered superior. It is concluded that a 50 mm sub-caliber APCR round fired from a 75 mm gun has better penetration than a full-caliber 105 mm round, and with higher shell velocity to boot. The author recommends choosing a 75 mm gun.

Report on the activities of the 1946 armor committe

This memo is a report on the activities of the armor committee of 1946, up to October 1st 1948. The committee has consisted of various officers and engineers from the army headquarters, the army ordnance administration and the armor school, and it has taken the form of an open forum where various ideas regarding armor development could be discussed. The report gives pretty good summary of the thoughts behind the Swedish armored vehicle developments of the late 40’s.

Archive reference: SE/KrA/0062/D/01/016:H/F I/18

Memo regarding APCR

This memo (dated 1946-12-03) discusses a new and interesting ammunition technology, namely projectiles with a core of a brittle but very hard metal, such as tungsten carbide. In order to keep the high speed of the projectile, various technologies (such as conical guns and sub-caliber saboted rounds) are possible. The author recommends contracting Bofors to develop such ammunition for trials with the 75 mm pvkan m/43, and that some in-house trials with the 37 mm pvkan should also be conducted.

Archive reference: SE/KrA/0062/D/01/025:H/F I/2

The beginnings of the bkan 1 program

In the same 1949 army headquarters memo mentioned in the previous post, the army also saw the need for a 15 cm self-propelled autoloaded artillery gun (the 10,5 cm gun was intended for smaller formations, while the 15 cm SPG would be a division or corps-level asset). Development of this artillery piece was contracted to Bofors, with deliveries planned to start in spring 1956 (in reality, the production version of this SPG finally entered service in 1967, delayed over 10 years).

These documents describe the original intentions and requirements for the SPG, and a preliminary drawing is attached. It was originally intended to weigh 30 tons; the production version would eventually enter service weighing 52 tons. A large part of the increased weight was due to a requirement added later, namely that the entire fighting compartment and the external ammunition storage must be armor protected and sealed against NBC weapons.

Archive reference: SE/KrA/0062/D/01/016:H/F I/17 and SE/KrA/0062/D/01/016:H/F I/18

Considerations regarding self-propelled 105 mm howitzer (1949)

A few documents from 1949 regarding the development of a self-propelled 105 mm howitzer. This project has been seen before on this blog, but these documents seem to be where the project first originated, namely with a memo from the army headquarters regarding replacement of older artillery pieces.

The documents mention that Bofors proposes to mount a modernized version of the existing haubits m/40 on the chassis of the lvkv fm/49 SPAAG, but to save costs KATF is ordered to investigate if it’s possible to mount the same artillery piece on a very light tankette chassis that is being developed at Landsverk. Bofors is said to be skeptical, but the investigation proposes three alternatives for doing so (called a, b, and c; drawings are attached). Alternative a is notable for having the gun mounted backwards on the chassis, but alternative c is considered to be the most suitable.

For whatever reason the project never got off the ground and a self-propelled 105 mm artillery piece would continue to be discussed for several years until the project was ultimately cancelled for cost reasons at some point in the 60’s.

Archive reference: SE/KrA/0062/D/01/016:H/F I/17

List of Landsverk tanks as of April 1949

A letter from Landsverk to KAFT (dated 1949-04-09), containing data and drawings of some of the then-modern tanks produced there, as well as proposed data and drawings for a number of planned tanks developed by the company at their own expense.

It may be worth mentioning that most of the tanks have “motyl 25” listed as their fuel. Motyl 25 is a mixture of ethanol (that is to say, alcohol) and regular gasoline in the proportions 25% ethanol and 75% gasoline. During WW2 this was used extensively to help offset the Swedish oil shortages, but in those times both motyl 50 (50% ethanol) and motyl 75 (75% ethanol) were common. Today, we see the same thing in the form of the commercial E85 fuel available at many gas stations.

The reason this is in an archive volume dated 1948 is that apparently the same list was sent over in September that year, but KAFT seems to have misplaced some pages so it was sent over again and apparently the bureaucracy found it appropriate to place both the letter and the complete list together with the original list. Most of the pages are present twice in the archive volume.

Archive reference: SE/KrA/0062/D/01/016:H/F I/15