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Strv m/42 Delat torn


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This thread is part of the Swedish tech tree project and one of the threads where I will go more in depth with sources and information which I have not included in the main thread. As I said in the main thread Im currently sitting on about 30 000 pages of information from the Swedish war archive so if there is anything that is unclear please PM me and I will provide a source

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Strv m/42 "Delat torn"

 

History

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In September 1943 Bofors under orders from KAFT started working on a new turret for the Strv m/42 and Strv m/41. It had been specified that the turret had to be no heavier than the current one as to not sacrifice armor protection. It was also requested that the gun be equipped with an autoloading mechanism and be more potent than the current 75mm Strvkan m/41.

 

The first drawings for the new turret were submitted for KAFT approval On the 22nd of March 1944. This turret featured the newly developed 75mm Pvkan m/43 gun mounted outside the enclosed part of the turret. Essentially the gun sat in a sort of cradle in the middle surrounded by the commander and gunners position on the right and the loader’s position on the left. Due to the strange configuration, this new turret was nicknamed “delat torn” (Divided turret). The autoloading gun was fed by a five round magazine which would be fed by the loader. The gun had an estimated mechanical rate of fire of 20 rounds per minute and In total, the tank carried 42 rounds of ammunition. KAFT’s general response to the design was positive, however, it was clear that the 22-ton weight limit would not be kept. And a letter along the lines of “considering foreign developments we can not afford to stop our tank development because of a weight limit” was sent to the head of the army.

 

“Delat torn” drawing
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By winter 1944 a wooden mock-up of the “delat torn” had been finished and mounted on a Strv m/42 chassis. A functional prototype with some minor changes like reducing the turret height by 100 mm to be more in line with the current strv m/42 turret, and reducing the capacity of the loading tray from 5 to 3 rounds. However, with an estimated delivery time of spring 1945 for the “delat torn” prototype, a number of less extensive solutions had also been discussed.

 

Strv m/42 with delat torn mock-up
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In early 1945 the development of the “delat torn” intended to arm the new tanks was starting to show problems. The work on the prototype turret was slow and the originally intended delivery date could not be kept. In fact, the prototype turret would not be ready for another year.

 

Strv m/42 with Delat torn prototype

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On May 16 1946 the “delat torn” prototype was finished and demonstrated for army personnel. A test firing was conducted without issue and the loading mechanism was deemed ready. A number of minor faults were noted however. In particular, the mechanism for elevating the gun was exposed so it was suggested to add an internal mantlet. Several plates would also be mounted to to help protect the exposed loading mechanism from the side and above. During further testing in August, more faults became apparent. There were problems with aiming system and the autoloader would sometimes seize up. But at least the best performance of the autoloader was determined as 4 rounds in 8,2 seconds.

 

Sketch of the proposed changes
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In June 1947 The “delat torn” prototype was used in troop trials at the armor school. The evaluation of the turret described it as using surprisingly primitive design. The commander’s cupola had only 4 viewports and the loader was not even connected to the internal radio system, he also lacked the optics to efficiently use the machineguns. The loader’s position was such that he was constantly standing in an awkward position where he had a hard time keeping up with the turrets rotation. It was also found that during firing of the main gun the cloud of dust created would make it impossible to observe where the round had impacted. The dust would also stick to the exposed elevation gearing and loading mechanism. The heavier turret had however not impacted the mobility of the Strv m/42. The trials were discontinued in August 1948.

 

Note that this section is an excerpt from my full article, which can be found here: https://fromtheswedisharchives.wordpress.com/2018/08/30/swedish-tanks-ww2-medium-tank-projects/

Please check it out (or contact me) for more detailed information on the tanks development.

 

 

Data

 

Strv m/42 "Delat Torn"

Combat weight: 23,5 ton
Crew: Commander/Radioman, loader, Gunner, Driver (optional Machinegunner)
Length: 6070 mm (hull)
Width: 2340 mm
Height: circa 2585-2600 mm
Top speed: 45 Kph
Gradient: 40 dg
Side slope: 30 dg
Trench: 2,4 m
Ground clerance: 400 mm
Track width: 380 mm
Ground contact length: 3725 mm
Ground pressure: 0,82 kg/cm^2
Turning radius: 4,5 m ("on the spot steering")
Turning radius: 6,5 m (normal steering)
Vertical step: 0,9 m
Fording: 1 m
Engine: Volvo A8B (Gasoline 410 hp at 2300 rpm)
Power to weight ratio: 17,4 hp/t


Armor hull: 55/30/20
Armor Turret: 60/30/30


Main armament: 7,5 cm Pvkan m/43 L/54 (Autoloader)
Magazine size: 3 rounds (+1 in the breech)
Rate of fire: 20 rounds per minute
Secondary armament: 3x 8 mm ksp m/39 strv
Gun elevation/depression: +10/-10 dg
Ammo: 42 rounds 7,5 cm, 3000 rounds 8 mm
Traverse (hull mg): 18 dg right, 17 dg left

 

Note: For more details on the chassis check out the Strv m/42 and variants post:

 

 

Main armament:

 

Spoiler


General data See: Description and drawings for 7,5 cm Pvkan m/43

 

Ammunition types:

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Source: https://i.imgur.com/WD3LE3u.jpg

 

 

Sgr m/38 (HE)
- Shell weight: 12,06 kg
- Projectile weight: 6,73 kg
- Muzzle velocity: 810 m/s
- Filler: 0,69 kg tnt & 0,78 ball barings

 


Slpprj m/41 (AP-T)
- Shell weight: 12,07 kg
- Projectile weight: 6,69 kg
- Muzzle velocity: 815 m/s

 


Slpgr m/43 (APHEBC-T)
- Shell weight: 11,56 kg
- Projectile weight: 6,00 kg
- Muzzle velocity: 890 m/s
- Filler: 0,11 kg tnt

 


50 mm slpprj m/49
- Shell weight: 9,62 kg
- Projectile weight: 3,70 kg (2,60 kg sabot)
- Muzzle velocity: 1110 m/s


7,5 cm hpgr M/44 slj M/42 (APHE-T) !!Navy only!!
- Shell weight: 12 kg
- Projectile weight: 6,8 kg
- Muzzle velocity: 840 m/s
- Filler: 0,19 kg tnt

- Penetration: http://- Penetration: http://www.ointres.se/1951_omg_7-2_kungstiger.jpg
 

 

Penetration: Slpprj m/41 (see lvkan m/37)

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Penetration: Slpprj m/49 (Note The production version of this round was first used one year after the cancellation of the Delat torn project)
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Penetration: Slpgr m/43
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Drawings

Spoiler

Original 1944 drawings from Bofors showing Delat torn turret on Lago 1 chassis. We can tell its the lago 1 chassis from the shape of the drivers position and shape of the side air intakes for the engine deck

Note that it is not a exact match for the prototype turret as its 100 mm taller and is more angular. Migher resolution Tiff files are available by contacting me.

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Overview drawing of the 1944 bofors drawing turret

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Recreattion of prototype turret based on phothos of the prototype and mockup and the above original drawing

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(Note that it lacks the canvas cover over the loading mechanism)

 

 

 

Source's & Historical Refrences


- Landsverk Blueprint archive (Part of Krigsarkivet in Stockholm) https://riksarkivet.se/krigsarkivet

- SPHF's (swedish historical armor association) private archive

Pansar magazine issue 1 2016

http://tanks.mod16.org/2014/02/01/list-of-landsverk-tanks-as-of-april-1949/

http://tanks.mod16.org/2014/01/11/memo-regarding-guidelines-for-new-afv-development-1944/

http://tanks.mod16.org/2014/01/08/minutes-of-meetings-regarding-a-better-gun-for-strv-m42/

http://tanks.mod16.org/2014/02/05/report-on-the-activities-of-the-1946-armor-committe/

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  • 1 year later...
3 minutes ago, Wolf_89 said:

Looking forward to play Swedish tanks :) 

Sad we have to wait a few more months :crying:   :) 

Maybe we'll get the premium starters with 1.95 ...

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  • 3 weeks later...
On 13/12/2019 at 17:44, Rieskaruisku said:

Calculator gives a penetration value of 233mm for Slpgr m/43 (APHEBC-T).

+1

uhhh how exactly did you get that result?

bTe5zhe.jpg

this is how it should look...

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  • 2 months later...
  • Senior Suggestion Moderator

Moved to Implemented suggestions.

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