Posts in Category: Source documents
Mostly untranslated photos of various official documents I’ve found in the archives. Probably not very interesting to you if you can’t read Swedish.
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
TLP and pvkv fm/48: the story of a cancelled project
This small collection of documents (letters, memos, minutes of meeting and blueprints) tells the short and sad story of the Landsverk TLP, which was to be a 30-ton tank destroyer armed with a 105 mm gun. It lived a very brief life on paper at Landsverk and Bofors for a few short months in 1947, until the army changed its mind and decided it didn’t want AFV’s in that weight class after all. Before cancelling the project entirely, the possibility of improving the protection of the existing pvkv m/43 by angling its armor plates better and potentially upgunning it to 105 mm was investigated (that part of the project was called “pvkv fm/48” by Landsverk), but the conclusion was that the protection would not be improved and the entire thing came to nothing.
Archive reference: SE/KrA/0062/D/01/016:H/F I/13
Memo regarding guidelines for new AFV development (1944)
Original title: VPM med förslag till riktlinjer för planering och utprövning av nya stridsvagnar mm.
This memo (dated 1944-11-29) suggests guidelines for future AFV development. It starts off with discussing foreign developments, and states that the general opinion seems to be that anti-tank weapons have reached such a degree of efficiency that merely building more heavily armored tanks no longer seems cost-efficient. At the same time, the demand for “support tanks” (self-propelled guns and tank destroyers) is on the rise.
With this in mind, the memo suggests a number of new developments, mostly improvements of existing designs, and suggests that using the new “split” turret with an automatic gun rammer (currently under development at Bofors) might be a good idea.
Archive reference: SE/KrA/0062/D/01/016:H/F I/4
Minutes of meeting (1941-04-30) regarding development of new AFV’s
Original title: Sammanträde ang. strv m.m. å MB3 den 30 april 1941
This document contains minutes of a meeting held on 1941-04-30, where the requirements for a new tank and/or tank destroyer are discussed. The decisions made at this meeting led to the development of the strv m/42.
The meeting starts off with an overview of the tanks currently available to the Swedish army (48 strv m/37, 16 strv m/38 and 20 strv m/39), as well as the ones ordered but not yet delivered (100 strv m/40 to be delivered before the end of 1941 and 116 license-built TNH with deliveries starting summer 1942). The meeting participants conclude that neither current tanks nor current towed anti-tank guns (mostly 37 mm Bofors) are sufficient to fight modern German or Russian tanks, and that it is necessary to develop either a new, heavier tank or a self-propelled anti-tank gun of some kind, and quick.
Three current Swedish tank development alternatives are presented: the Landsverk Lago (originally intended for Hungary), the Landsverk Terro (a 14 ton tank with a 57mm gun and 50 mm frontal armor) and an unnamed design proposal for a 22 ton tank with a 75mm gun and about 70mm frontal armor.
Weight restrictions are brought up. If strategic mobility is disregarded, tanks suited to Swedish terrain should weigh max 30 tons, but since tanks have to move along roads and over bridges, the meeting concludes that a new AFV (tank or TD) must not weigh more than abut 20 tons in order to retain sufficient strategic mobility.
Some discussion follows, with several different proposals from the meeting participants. Someone proposes a 20 ton TD with a 75mm gun and 70mm front armor, but is met with opposition and the counter-argument that Swedish terrain is better suited to more mobile anti-tank guns, and that the Swedish military attache in Berlin reports that tanks are the best weapon for fighting tanks. Someone else then proposes an 18 tank with a 105mm short-barreled howitzer, but this idea is not received favorably since both the precision and the rate of fire would be low.
In the end the meeting decides that development should focus on a 20 ton tank with 60 mm of frontal armor and armed with a 57mm gun (or alternatively a 75mm or 105mm gun), with a max speed of 40 km/h.
Archive reference: SE/KrA/0062/D/01/016:H/F I/1 a