Bofors and Tolfvan bombs

[Dreamk]

Can someone post details about pre ww2 Bofors bombs - It seems that besides the bombs manufactured in Finland under the label Tolfvan, between 1930 and 1939, Bofors produced also an other, somehow earlier range, of bombs under the appellation Bofors Finland. I have only found 2 bad quality photos of this production.
1935 series

1939 series

The full 1939 catalogue of Tolfvan bombs can be dowloaded at
http://digi.lib.helsinki.fi/pienpai...347159&publisher=Tolfvan+A.B.+O.Y.&alphabet=T
Of special interest both on the Bofors series and on the Tolfvan, the fins devised to give a rotation to the bombs, a development of the pattern used on WW1 PuW bombs.

 

[spotter]

Bofors bombs from 1931 book

 

[Dreamk]

Thanks Spotter! I understand that these were the bombs exported to Argentina for use on their Junkers bombers.
BTW Lithuanian airforce used Tolfvan bombs, though there they were known under the mis-spelled appellation of Tolfran

 

[Dreamk]

Another piece of info that just fell in my hands - the strange "step" at teh junction of the bomb body and nose, that one sees on the Bofors 1935 photo, may have had a functional purpose - to fit a specially devised bomb rack - a patent deposed in 1931 by Tolfvan....in the Czech republic. Did the Czech use Tolvan bombs by then?

 

[Tmine35]

I have a catalogue from Oy Tolfvan Ab, a Finnish company as a pdf. It is quite different from what Spotter has sent.
It's 16 pages and I have some problems to post it here but if you PM me your email address I can send it direct to you.

 

[Dreamk]

I have a catalogue from Oy Tolfvan Ab, a Finnish company as a pdf. It is quite different from what Spotter has sent.
It's 16 pages and I have some problems to post it here but if you PM me your email address I can send it direct to you.

Hi Tmine
Is it a different one from this one?:

The full 1939 catalogue of Tolfvan bombs can be dowloaded at
http://digi.lib.helsinki.fi/pienpain....Y.&alphabet=T

 

[Tmine35]

No, it's the same one. Sorry, didn't read your first message all the way.

 

[Dreamk]

No problem. BTW do you have info on the colors and markings on these bombs? I found only 2 colour photos - both of bombs from teh continuation war period (post 1941)
One, from a bomb in dispaly at the Helsinki war museum, shows a Tolfvan 250kg in blue paint (general engineering equipment paint of the period - same as on some contemporary soviet bombs - and as a matter of fact a general practice in the Interwar period - lorry or locomotive paint used for bombs as anticorrosion agent)
The other from a Finnish book on a Bleinheim Bomber squadron shows an overall green (somehow yellowish) paint with a red (yellow?) band around the nose - bad quality photo.
On B&W photos the Tolfvan bombs appear generally as if they were unpainted, sometimes with a (red?) band around the nose

 

[Tmine35]

The color is an interesting question. I have Finnish Air Force bomb manual from WW2. It describes some Tolfvan bombs and also several other models. The manual says nothing about bomb color - just that all stencils must be bright yellow and which letters, font type and size to be used and what to stencil but nothing about stripes or similar. I have a tail of 12,5 kg HE-bomb, possibly Tolfvan type(?) and it is painted field grey - little more brownish than German field grey but not as brown as Russian.

 

[Dreamk]

Tmine Hi
The grey paint is expected - this was a current anti-rust protection in the period on heavy metal utilitary objects, and you''l find it on quite a number of bombs (The Italian for instance) it's a medium grey paint that is still produced and available in some parts of Europe till present day.
Could you scan/upload the part with the details of fonts and what to stencil?
Thanks

 

[Tmine35]

This part of the manual is text only and in Finnish language - not much to scan here. Here a short summary of the main points.

Stencilled markings on bomb body were done with bright yellow paint ( Chrome- or Cadmium yellow ). Font for bombs up to 50 kilos is Grotesque 4 and bigger ones Grotesque 6. The same font type was used for artillery ordnance stencils as well.

Stencilled was:
-Explosive type
-Explosive maker
-Filling place and year

Explosive markings:
-TNT
-TTX ( mixture of TNT and Trinitroxylol )
-MR ( Black powder )

Explosive maker
-BN ( Bofors Nobelkrut )
-ICI
-SK ( Finnish )
-R ( so called French TNT )

Example markings:
TNT/BN
SFD/39 ( this must be a Bofors filling station? The other ones below are all Finnish depots )

TNT/ICI
AL/32

TTX/SK
AL/31

MR
AV 1 /31

I don't think this is of much help to you as this is a general instruction for all bombs used in Finland, not only Bofors/Tolfvan bombs.

The manual says nothing about markings on incendiary bombs which however are described in manual.

 

[Dreamk]

Thanks for the info.
The fact that the stencilling was in yellow paint leads to think thet the bombs were painted in medium-dark shades and no longer let unpainted, at least by the time this manual was writen.
Concerning Incendiary bombs, it's not surprizing, most were left unpainted as often their metal was a chemical reactive metal (magnesium, elektron and such) - only when the bomb was made from an iron/steel shell conatining incendiary "candles" or "materials" it was then painted with anti-corrosion paint (per example the French 10Kgs and British 25 lbs incendiaries).
BTW did the Fins use Swedish bombs such as the 12kg sprngbomb m/37 or 50 kg and 250kg minbomb m/37 or the 6kg brandbomb m/39?

 

[Tmine35]

Sorry but Swedish bombs are not my field, if i see drawings I can compare them to Finnish manual drawings. The manual has only Finnish nomenclatures for bombs, without declaring if they are imported or locally made.

Finnish incendiary bombs were Electron, Electron-Thermite and white phosphorous filled steel shells. At least the steel bodies of phosphorous bombs should have been painted.

 

[US-Subs]

Electron is magnesium?

 

[Dreamk]

Elektron is a magnesium alloy developed in Germany during the First World War as a substitute for aluminium alloy. It was used to make incendiary bombs as it was light and, once ignited, it could not be extinguished and burned at such a high temperature that it could even penetrate armour plate (a problematic side effect if your original intention is to find a substitute to aluminium to produce cooking pans and such necessary homeware lacking in wartime)

 

[Dreamk]

WW2 Swedish bombs
12kg sprngbomb m/37
50 kg minbomb m/37
250 kg minbomb m/37
6kg brandbomb m/39
250 kg minbomb m/40
500 kg minbomb m/41
250kg pansarbomb m/41 (?)
50 kg sprngbomb m/42
50 kg minbomb m/42
Lysbomb m/43
Torped m/17
Torped m/38
pansarbomb =AP/SAP minbomb= HE sprangbomb= Frag Lysbomb=Flare

Here are the few pics I could find of these bombs

50kgM37

500Kg Minbomb

All additionnal info would be wellcome

 

[Dreamk]

A few more pics
500kg Minbomb at the Swedish Air museum

Post ww2 Swedish bombs - some are still of the same shape as the ww2 ones.

 

[Tmine35]

All bombs in my manual ( up to 250 kilos ) have nose- or tail fuze or both. They all look quite different from Swedish bombs.
The manual is not dated but describes "nose fuze M/42" so it must be from 1942 or later. Cover sheet says it's volume I of manual, would be interesting to see vol. II.
In 1942 we used also British 25 Lb bombs and German 50...1000 kilos which are not mentioned in manual vol. I.

 

[Dreamk]

One possibility is that Soviet bombs were also used and are shown in this manual
http://sovietwarplanes.com/board/index.php?topic=685.msg3412#msg3412
The russian arms forum has a number of very good illustrations and technical descriptions of Soviet bombs (yes it's in Russian, but the graphics are easy to understand for everyone) http://www.russianarms.ru/forum/index.php/board,797.0.html

 

[Tmine35]

Russian bombs are also totally different than those in Finnish manual. I have a part of another old publication describing Russian bombs and fuzes, but have a feeling that manual was mostly for EOD purposes.