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Hypothetical question about German Type 17 Fuze with Zus 40

P

Peteaguy

New Member
This is just a thought that occured to me an I was wondering if any one had any thoughts as to if it was feasable. Not that I am going to encounter this situation and I would be leaving to to others for self preservation reasons.

The Zus 40 was intended to prevent the removal of the fuze above it and would fire when the gaine of the top fuze was withdrawn from the top cavity. The Zus 40 has blades to prevent it being removed with the upper fuze.

zus40.png
The whole fuze assembly is held into the bomb by a lock ring (just a externally threaded nut) and a locating ring (has a notch for the locating pin on the fuze and a pin to orientate the ring to bomb body).
Lockring.png
Lockring1.png
So the question is this: Would it be possible to remove the upper fuze leaving the Zus 40 and the gaine from the upper fuze in the bomb by undoing the lockring, removing the locating ring and turning the upper fuze to unscrew the gaine? This obviously relies on using the blades in the Zus 40 to provide sufficient grip on the upper fuze gaine to allow it to be unscrewed. And would obviously be risky proposition with a Type 17 upper fuze as turning it round multiple times would mess with the clockwork mechanism even with a magnet stopping it. It would be suicidal with a Type 50 in the mix.

As well a pondering stuff I am looking for some information, if anyone could provide or point me in the right direction for the dimensions (have very rough ones but am looking for something a bit more accurate) of fuze, fuze pocket, lockring and locating ring for German (Rheinmetall Electic Fuzes) ww2 SC-50 and SC-250 bombs?
And does any one know if there is statistics (internet, books, archives) for number of German ww2 bombs dropped, numbers of UXBs, fuze type for UXBs, UXB result (unprovoked detonation, detonated by external factor, defuzed) out there anywhere?

Many thanks
Peter
 
Welcome.
That's a hell of a lot of questions in one post.
The best books are:
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and
 
Well, theoraticly you could. After removing the top ring one would have to lift the fuze at least 10mm (measured it) to release the orientating pin of the ELAZ 17 from it's slot and than start to rotate. This10mm is about 2/3 of the length of the vertical release pin (16mm long) of the ZUS 40, before ending on the curved end of the pin. What you do not know while unscrewing the fuze is if the gaine is also unscrewing, or is tight and you are still rotating the gaine, making it rise with the fuze. You'd be depending on the Greman armourer that either loosely installed the gaine either tightened it with a plier.
So, at best it's a suicidal gamble in which you're litteraly playing with your life.
 
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LEI-13-HG What can I say I am an inquisitive chap. Thanks I will get hold of those references.

​

pzgr40 I did not think it would ever be something I would want to try. Though I believe one was recovered by crow baring it out of the bomb so maybe it has a similar risk profile. I just looked like it would be possible and I wondered what others who have access to examples thought. Thanks for your thoughts.
 
Peteaguy said:

​

pzgr40 I did not think it would ever be something I would want to try. Though I believe one was recovered by crow baring it out of the bomb so maybe it has a similar risk profile. I just looked like it would be possible and I wondered what others who have access to examples thought. Thanks for your thoughts.
Click to expand...

That was clear to me that it was a hypothetical question, as bombs found these days with a ELAZ 17 are completely corroded, and the only way to remove the ring from the fuze well is with a hammer and chissel, which is also suicide with a delicate clockwork inside that may hang on a spec of dust. With the cutaway I made from a ELAZ 17 with a ZUS 40 in the fuze pocket I used an empty fuze pocket with the ring still in place and I could only remove the ring with a hammer and chissel after cutting a quarter out of the fuze pocket and heating the top of the fuze pocket and using lots of WD 40. The aluminium of the fuze will be bloated, especialy if the ground found in is alkaline, you would not even be able to read any texts on the fuze head any more desciding what fuze it is exactly.
I think that in the 1940's a number of british EOD personel will have lost their lives by ZUS 40 boobytrapped time fuzes, before finaly one realized that bombs were boobytrapped. There were no portable X-ray machines that could look for the signature double boosters, so I think in many cases these brave men were litterally dicing with dead.
One should also understand that wartime standards are different from peace time standards, German bombs these days are mostly blown in situ, as propperty damage is -thank god- observed as not important compared to personal safety.
www.bbc.com

What do we know about unexploded WW2 bombs?

During the war Britain was scattered with bombs, but what happened to the ones that never exploded?
www.bbc.com www.bbc.com

But to fully understand the danger these bombs still pose today, a short time ago a German bomb was found in one of the baltic states, and when the capacitator was measured, it still was appr. 30% loaded AFTER MORE THAN 80 YEARS, still enough to fire a squib igniter.
 

Attachments

  • Pict 01 - Fuze pocket met El.A.A 17 en ZUS.40.jpg
    Pict 01 - Fuze pocket met El.A.A 17 en ZUS.40.jpg
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pzgr40 said:
That was clear to me that it was a hypothetical question, as bombs found these days with a ELAZ 17 are completely corroded, and the only way to remove the ring from the fuze well is with a hammer and chissel, which is also suicide with a delicate clockwork inside that may hang on a spec of dust. With the cutaway I made from a ELAZ 17 with a ZUS 40 in the fuze pocket I used an empty fuze pocket with the ring still in place and I could only remove the ring with a hammer and chissel after cutting a quarter out of the fuze pocket and heating the top of the fuze pocket and using lots of WD 40. The aluminium of the fuze will be bloated, especialy if the ground found in is alkaline, you would not even be able to read any texts on the fuze head any more desciding what fuze it is exactly.
I think that in the 1940's a number of british EOD personel will have lost their lives by ZUS 40 boobytrapped time fuzes, before finaly one realized that bombs were boobytrapped. There were no portable X-ray machines that could look for the signature double boosters, so I think in many cases these brave men were litterally dicing with dead.
One should also understand that wartime standards are different from peace time standards, German bombs these days are mostly blown in situ, as propperty damage is -thank god- observed as not important compared to personal safety.
www.bbc.com

What do we know about unexploded WW2 bombs?

During the war Britain was scattered with bombs, but what happened to the ones that never exploded?
www.bbc.com www.bbc.com

But to fully understand the danger these bombs still pose today, a short time ago a German bomb was found in one of the baltic states, and when the capacitator was measured, it still was appr. 30% loaded AFTER MORE THAN 80 YEARS, still enough to fire a squib igniter.
Click to expand...
I think that in the 1940's a number of british EOD personel will have lost their lives by ZUS 40 boobytrapped time fuzes, before finaly one realized that bombs were boobytrapped. There were no portable X-ray machines that could look for the signature double boosters, so I think in many cases these brave men were litterally dicing with dead.
One should also understand that wartime standards are different from peace time standards, German bombs these days are mostly blown in situ, as propperty damage is -thank god- observed as not important compared to personal safety.

From memory the EOD only found about the ZUS40s because a bomb broke apart and exposed the fuse pocket containing a 17 and ZUS40
 
In addition to the technical problems of the design, there is another one with the Gr.f. 88 .
During the recrystallization of this charge, there may also be a problem in that it will be particularly sensitive to friction.
Any chiseling (with a chisel) etc. is problematic in the sense that you do not have information about the state of the explosive in the det. and not only in it.
Sensitivity to mechanical stimuli will also have to be taken into account, especially those that get between the friction surfaces of metals.
Today I would completely eliminate the chisel from the action...

Akon
 
millsbomber said:
I think that in the 1940's a number of british EOD personel will have lost their lives by ZUS 40 boobytrapped time fuzes, before finaly one realized that bombs were boobytrapped. There were no portable X-ray machines that could look for the signature double boosters, so I think in many cases these brave men were litterally dicing with dead.
One should also understand that wartime standards are different from peace time standards, German bombs these days are mostly blown in situ, as propperty damage is -thank god- observed as not important compared to personal safety.

From memory the EOD only found about the ZUS40s because a bomb broke apart and exposed the fuse pocket containing a 17 and ZUS40
Click to expand...
Yes, indeed. Not sure about the 50, but the 17, Y and Zus 40 were all discovered due to faulty/non-functioning examples - and, fortunately, all discovered/found very soon/within days after their introduction of use against Britain, allowing scientists to reverse-engineer them and come up with fairly quick countermeasures.
 
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