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8,8cm SprGr PAtr Flak 41

pzgr40

Well-Known Member
Premium Member
8,8cm Spr.Gr. Patr. Flak 41

Cutaway model a 8,8cm SprGr. Patr. Flak 41 (SprGr. Patr. Is the German abriviation for HE shell)
As early as 1938 the conclusion in Germany was that the current Flak 18, 36/37 anti aircraft guns were soon te be obsolete, especially looking forward into the future plans for Germany. Therefore the Rheinmetall company was asked to develop a new 8,8cm Flak gun -also suitable for land and sea targets- , with the project name “gerät 37”. The following design data were required:

Vo: min. 1000 mtrs/sec
Shell weight : 9,4 kg
Total weight of gun : max. 8 tons
Rate of fire : 25 rpm
Suitable for use against air-, sea-, and land targets.

As the development at Rheinmetall fell behind, so in 1941 the development was transferred to Krupp which changed the name Gerät 37 into Flak 41. In the summer of 1941 the first Flak 41 gun was delivered to the luftwaffe for testing purposes. In 1942 problems extraction problems with steel shellcases were reported and the steel shellcases were replaced with brass ones. Only after adjustments to the chamber in the barrel steel shellcases could be used again.
In 1943 the development of the Flak 41 at Krupp was stopped as the German army wanted Krupp to concentrate on design and production of anti tank guns. The development was –temporary- transferred to Skoda, but was finaly passed back again to Rheinmetall.

The difference between the flak18 and the Flak 41 can be observed from the data below:

Flak 18 compared to Flak 41
Barrel length: 4,930mm -- -- 6548mm
Length rifled part of barrel : 4093mm -- -- 6411mm
Vo: 840 Mtrs/sec -- -- 1020 mtrs/sec
Shell weight : 9,0 kg -- -- 9,4 kg
Powder charge: 2,325kg -- -- 5,5 kg
Ceiling: 10.700 mtr -- -- 19800 mtr
Max. range: 9800 mtr -- -- 15000 mtr
Length shellcase : 570 mm -- -- 855,1 mm
Cartridge length : 930 mm -- -- 1197 mm

The following number of Flak 41 guns were delivered to the Luftwaffe:
1942 : 44 guns
1943 : 122 guns
1944 : 291 guns
1945 : 75 guns

In total 532 guns were produced during WW2.

The pojectile body is made from mild steel and has soft iron driving bands. The inside of the projectile body is threaded M50x3 in top. A bushing housing the booster charge (the “Mundlochbuchse”) is screwed in top of the projectile body, locked up by the fuze. The Gr.Zdlg C98 NP (Grosse Zundladung C.98 Nitropenta) booster charge is placed in the mundlochbuschse; this consists of an aluminium cup, filled with nitropenta (pink), with a heat sensitive detonator in top. Above this detonator a spring loaded telescoping collar is placed. When the fuze is screwed onto the projectile, the collar is pressed tight against the base of the fuze, preventing the flame of the fuze from escaping sideways, leading it straight into the heat sensitive detonator.
In this case, a Zt.Z.S30 is placed on the projectile, but this can also be a Zt.Z S30Fg (Fliehgewicht), or -when used against land targets- an AZ.23/28 impact fuze. The explosive charge consists of a 1kg cast in charge of FP 60/40 (60% TNT and 40% Hexogen).

The shellcase is filled with a 5,5 kg charge of Gu.RP-KN powder sticks with a length of 740mm, and a 4,2mm diameter with a 1,5mm hole through. The main charge consists of a centre bundle of 4 kg, tied together with silk thread. The space around this bundle is filled with 1,5 kg lose powder sticks.
Below the centre bundle an ignition charge (beiladung) is placed, cosisting of a linnen bag filled with 20 grams Nz. Man. Np 1,5x1,5x0,5mm riflepowder that ignites the main charge of 5,5 kg simultaniously
In the base of the shellcase the C22 electric primer is inserted.
Since the problems with the steel shellcases were never completely solved to satisfaction, one descided to get around the problem. Some Flak 41 guns had a big M stamped in the breech block, meaning they were allowed to use brass (Messing) shellcases only.

On picture 04 the 8,8cm Pzgr.Patr.39-1 Flak 41 beside the 8,8cm SprGr.Patr. Fak 41. The 1 behind the 39 means that this armour piercing projectile used a better (harder and more ductile) steel quality. This was denoted by a white ink stamp 1 on the ballistic nose cap. The white nose tip denotes that it is a PzGr39, armour piercing shell wih the small explosive charge and the BdZ (base fuze ) 5127.
The Vo of the armour piercing projectile is 980 mtrs/sec. At 100 meters it is able to pierce a 194mm thick steel plate (and explode after passing through the plate), at 2000 meters a 127mm thick steel plate could still be pierced. So, even at 2000 meters allied tanks had no chance!

If you buy a Flak 41 High explosive shell for your collection, make shure -as it is an expensive cartride- to check the following: The HE projectile of a Flak 41 cartridge has a boat tail. 88mm HE shells without a boat tail -without exemption- are meant for the Flak 18, 36/37 and were never used on the Flak 41. So, always pull the projectile from the shellcase to check for the boat tail, or you could buy a costly mistake. The projectile of a Flak 41 HE shell –even of lesser quality- is three to four times worth a Flak 18, 36/37 HE projectile. The boat tailed 8,8cm SprGr. Patr. with small driving bands (as described in this posting) can also be used on the Kwk43 shellcase, although most people prefer the wide driving bands version on a Kwk 43 shellcase. The 8,8cm Spr.Gr Patr. with the wide driving bands however cannot be used on the Flak 41 shellcase. The small driving bands version was used with new KwK43 guns, the wide driving bands version was used with worn KwK 43 barrels.

On picture 05 one can see the size comparison of the German Heavy flak cartridges. From Left to Right; the 8,8 cm SprGr. Patr. Flak 18 36/37, The 8,8cm SprGr. Patr Flak 41, the 10,5cm SprGr.Patr. Flak 38 and on the right the 12,8cm SprGr Patr. Flak 40.


Regards, DJH
 

Attachments

  • 01 - 8,8cm Spr.Gr Patr. Flak 41.jpg
    01 - 8,8cm Spr.Gr Patr. Flak 41.jpg
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  • 02 - 8,8cm Spr.Gr Patr. Flak 41 projectile detail.jpg
    02 - 8,8cm Spr.Gr Patr. Flak 41 projectile detail.jpg
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  • 03 - 8,8cm Spr.Gr Patr. Flak 41 fuze detail.jpg
    03 - 8,8cm Spr.Gr Patr. Flak 41 fuze detail.jpg
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  • 04 - 8,8cm Spr.Gr Patr. Flak 41& 8,8cm PzGr39-1 Flak 41.jpg
    04 - 8,8cm Spr.Gr Patr. Flak 41& 8,8cm PzGr39-1 Flak 41.jpg
    235.6 KB · Views: 73
  • 05 - All SprGrPatr. for WW2 German heavy flak.jpg
    05 - All SprGrPatr. for WW2 German heavy flak.jpg
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If I compress the time -so no breaks and working continuously- :
drawing cutting line on shellbody and grinding, rasping and polishing shellbody. Polyestering, sandpapering and painting the shellbody - 8 hours
Drawing cutting line, sawing, rasping and polishing sherllcase - 4 hours
Taking apart the ZtZ S30, drawing cutting lines, cut fuze housing, cut gearbox, assemble - 5 hours
Producing powdercharge and make fillers in shell body and gaine - 5 hours
Added hours ; going to shop for tools or materials and to my grinding workshop - 4 hours

So together 26 hours in compressed time.

But of cource I do not work this way as I have a daytime job and for me it's hobby, so I work a few hours one day, the other day I don't. Looking back, it took me 2,5 week in on and off hours to produce it.

Of course it can be done much faster, but quality drops as soon as you shorten production time.
 
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