Finish pillbox with steel cupola

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KaiserChief
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Finish pillbox with steel cupola

Post by KaiserChief » 15 Feb 2008 07:34

Hello,

Does anyone have more informations about such pillboxes? Especially about the steeel cupolas used on them. Photos, drawings.....

Source: Military-engineering periodical, 1074;„–y0, 1944, s. 26-35, From the funds for Russian national library (Saint Petersburg)

V.
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JTV
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Re: Finish pillbox with steel cupola

Post by JTV » 01 Mar 2008 21:11

KaiserChief wrote:Hello,

Does anyone have more informations about such pillboxes? Especially about the steeel cupolas used on them. Photos, drawings.....

Source: Military-engineering periodical, 1074;„–y0, 1944, s. 26-35, From the funds for Russian national library (Saint Petersburg)

V.
Pillboxes and bunkers of various kind with steel cupolas were quite common among Finnish concrete fortifications. In fact they were so common that the question is bit like asking about German used bunkers with turrets - which is probably one of the reason, why there were no replies this far.

Finnish steel cupolas:

- M/39 observation steel cupola: The idea of observation cupola for bunkers had appeared already in early 30's and in late 1930's after testing M/39 cupola was introduced. It had 110-cm diameter, it weight 9 tons and was manufactured by Karhulan Konepaja (Karhula Engineering Works). This cupola model was commonly used in latest machinegun bunkers build just before Winter War. During the war it proved too weak (there are photos showing how sometimes top of the cupola had been broken off by Soviet artillery shells).
- M/40 observation steel cupola: This was stronger design developed from M/39. It was otherwise quite similar, but had thicker walls, so it weight 12 tons. The side that was located towards the supposed enemy direction was thicker than the opposite side.
- M/41 observation steel cupola: This design no longer had all around visibility due to having only to observation slits.
- M/44 observation steel cupola: Cupola for two men and just like M/43 mg-cupolas this had open rear allowing easier access from/to the bunker.
- Artillery fire control steel cupola M/40: Designed for artillery fire control after Winter War. This cupola did not have vision slots but a periscope. However soon Finnish military decided that it was more convenient and cheaper to just equip the bunkers intended for fire control work with periscopes than equipping them with cupolas of this type. So this was very rare design - only 30 made.
- M/40 light machinegun steel cupola: Already in 1930's Finnish military had considered machinegun cupola made from steel, but at the time Finnish industry was not capable manufacturing them at the time. Since then Karhulan Konepapaja had learned casting 12-ton cupolas, so the idea became reality in 1940. These machinegun cupolas were intended mainly for flanking fire and could also be placed in secondary positions behind the frontline. When compared to normal machinegun-bunkers they were easy to hide, since they protruded from the ground only 1.2 meters. Inside diameter 1.1 meters.
- M/41 heavy machinegun steel cupola: Improved higher version based to M/40.
- M/42 light machinegun steel cupola: Weight 5.1 tons, based to earlier designs.
- M/42 "rehearsal" machinegun steel cupola: Extra-light version designed because it was easier to transport in to the immediate frontline than heavier versions. Provided protection only against shrapnel. Weight 1.6 tons.
- M/43 light machinegun steel cupola: Weight 4.7 tons
- M/43 medium machinegun steel cupola: Unlike other models (which had one man) this was designed for two men.
- M/43 heavy machinegun steel cupola: Weight 13.1 tons, unlike other models (which had one man) this was designed for two men.

The terms light, medium and heavy with machinegun cupolas refer to weight of the particular cupolas (due to how thick they were), not to the weapons used in them. Firing sector of machinegun cupolas was about 50 - 60 degrees. Feedback from the frontline during Continuation War revealed that the soldiers in many units didn't like existing cupolas - man going to cupola had to climb there from the bunker below it and close the hatch under him. While in cupola he was isolated from other soldiers, with whom his only contact was a voice tube leading to bunker. From the cupola he had very limited visibility and could not know for certain what was happening outside. The feedback lead into development of M/43 machinegun cupolas and M/44 observation cupola, which all had open rear allowing easier route to rest of the bunker and hole on top the cupola for periscope to allow observing surroundings more effectively.

There don't seem to be production numbers for production before or during Winter War. During interim peace (1940 - 1941 in between Winter War and Continuation War) manufacturers (Karhula and Wärtsilä) manufactured cupolas:
- observation cupola M/39: 48
- observation cupola M/40: 231
- observation cupola M/41: 13
- fire control cupola M/40: 30
- machinegun cupola M/40: 41
- machinegun cupola M/41: 15
Large-scale production of steel cupolas continued during Continuation War. July of 1941 when Finnish military considered relocating resources used for manufacturing there were existing orders to Finnish industry for 1,064 steel cupolas of various types. The decision was to keep the production running and it seems to have done so until end of Continuation War (September 1944).

Weapons used in machinegun cupolas:
- DT tank machineguns
- DP light machineguns
- Maxim machineguns M/09
From these three options DT was the weapon that the machinegun cupolas had been originally planned for, it had attachment similar in armour plate as used in tanks and had 60 degree firing sector. The other two alternative weapons left a hole of 20 cm x 20 cm in front of the cupola and they had firing sector of only about 45 degrees. Also bunker version of Suomi M/31 submachinegun could be used from all observation and machinegun cupolas.

Attached drawings I scanned from excellent book "Suomen linnoittamisen historia 1918 - 1944" (History of fortifying Finland 1918 - 1944) by R. Arimo.

Jarkko
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JTV
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Re: Finish pillbox with steel cupola

Post by JTV » 01 Mar 2008 21:13

More drawings from the same book.

Jarkko
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JTV
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Re: Finish pillbox with steel cupola

Post by JTV » 01 Mar 2008 21:32

Few photos that I took from bunkers of Salpa line.

Jarkko
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JTV
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Re: Finish pillbox with steel cupola

Post by JTV » 01 Mar 2008 21:34

... And three more photos showing observation cupolas of some Salpa-line bunkers.

Jarkko
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KaiserChief
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Re: Finish pillbox with steel cupola

Post by KaiserChief » 07 Mar 2008 06:18

Hello

Thanks for answer.
So, it seems that cupolas from this picture: M43_mg_cupolas.jpg are the same as on my drawings.
Do you have some drawings with dimensions of M43 cupolas? Could you post some photos or drawings with
"small" bunkers equipped with steel cupolas? (like the ones on drawings I´ve posted)

V.

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JTV
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Re: Finish pillbox with steel cupola

Post by JTV » 07 Mar 2008 07:33

KaiserChief wrote:Hello

Thanks for answer.
So, it seems that cupolas from this picture: M43_mg_cupolas.jpg are the same as on my drawings.
Do you have some drawings with dimensions of M43 cupolas? Could you post some photos or drawings with
"small" bunkers equipped with steel cupolas? (like the ones on drawings I´ve posted)

V.
Yes, the cupola in your drawings seems to be machinegun cupola M/43. Unfortunately the text I wrote contains all the cupola measurements that I could find. What I remember at the time Finnish military didn't have any set of standard blueprints for building bunkers (the first set of such blueprints was made in 1947?). Especially after Winter War there were some basic bunker designs, which were build in large numbers (like: bunker with 45-mm at-gun + Maxim MG + small accomodation + observation cupola), but since they all had been adapted to the particular place and without specific blueprints, they all had at least minor differences.

BTW: Fin_1.jpg might not be a actual bunker designed for defensive lines, but a machinegun nest of sort used for boosting up the frontline defenses. The particular book mentions this kind of use for machinegun cupolas. In other words: It was not likely used in actual fortified defensive lines such as VT- and VKT-lines, but it may be a sample of how Finnish troops installed steel machinegun cupolas in the actual frontline. As you may know the Finnish front was basically having trench war from December of 1941 to June of 1944, the frontlines remained pretty much the same place. While both sides build trenches, dugouts, machinegun nests etc to the frontline for obvious reasons building large concrete structures would have been very difficult in there, hence the use of cupola in wood and soil structure. In actual defensive lines build in more peaceful settings (far from the frontline) the cupolas were probably used only in concrete bunkers (at least I have not found anything suggesting otherwise).

Jarkko

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Re: Finish pillbox with steel cupola

Post by 20P7 » 07 Mar 2008 20:38

Dear members,

have also a look into DAWA Nachrichten No. 50 where harry Lippmann published a nice article about the finish Salpa line with pictures of ths cupola types.

DAWA homepage:

http://www.deutschesatlantikwallarchiv.de

Greetings

Daniel

KaiserChief
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Re: Finish pillbox with steel cupola

Post by KaiserChief » 15 Jul 2010 11:13

I´ve found some drawings and photos of Finnish bunkers with steel cupolas in Fortoved magazine (1/2010)
cup_1.jpg
cup_2.jpg
cup_3.jpg
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KaiserChief
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Re: Finish pillbox with steel cupola

Post by KaiserChief » 15 Jul 2010 11:14

cup_bunk_I_1.jpg
cup_bunk_I_2.jpg
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KaiserChief
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Re: Finish pillbox with steel cupola

Post by KaiserChief » 15 Jul 2010 11:15

cup_bunk_II.jpg
cup_bunk_III_1.jpg
cup_bunk_III_2.jpg
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jopaerya
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Re: Finish pillbox with steel cupola

Post by jopaerya » 27 Oct 2015 12:32

Here some picture's from those cupola's http://forum.axishistory.com/viewtopic. ... 9&t=217131

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