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Z 17 Bm

FZG76

Well-Known Member
Ordnance approved
A little post about the Z 17 Bm fuze. Used for the destruction of guided bomb and more particularly the V1, I would like to know what the inscription "Bm" corresponds to.Indeed, there is also the "Am" version ..... Look marking on this
Thanks
z17%201.jpg
 
A little post about the Z 17 Bm fuze.Used for the destruction of guided bomb and more particularly the V1, I would like to know what the inscription "Bm" corresponds to.Indeed, there is also the "Am" version ..... Look marking on this
Thanks
 
Hallo @FZG76,
the LZtZ (17) Bm (Langzeitzünder=Long Delay Fuze) is a so called "Zerstörzünder"(Demolition-fuze) with a settable delay of 5-120 minutes. It was used in some special long range ordnance (like V1) to assure detonation of the warhead even if all other fuzes failed. Also it was used as a general demolition fuze where short delays, in the above range, were needed. As to your question about Bm and Am, I'm not shure, but think that they have different timing-ranges. I'll look if I can find something.
Bellifortis.
 
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maybe the builder, Bm for Allgemeine Elektricitäts gesellschaft (AEG)
 
Hi @FZG76,
no, that fuze designation has nothing to do with the manufacturer. The (17)A fuze has a settable delay of 2-72 hours. They all used Thiehl clockworks.
Bellifortis.
 
Yes, this is a Z(17)A with a settable delay of between 2 and 72 hours. The LZtZ(17)Bm that I have seen, had no markings on the body anywhere. I suppose that the "m" behind the "A"and "B" means mechanical (mechanisch) because most of all german airforce fuzes were armed electrically. These, only mechanically armed fuzes, needed to be handled much differently and had to be shackeled in, similar to allied fuzes. Also, our longtime member @PZGR40 has published a very good work about this same fuze in english. Attached is a page from the internet published by SKB company.
 

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Thanks Bellifortis, I didn't know there were two models for the Z17.Bm and Am.
 
Thanks Bellifortis, I didn't know there were two models for the Z17.Bm and Am.
 
The Z. 17 Am, with its very long running clockwork, will not normally have been used by the airforce. It's a pure, long delay, demolition fuze. For this use green is the better colour. Red shows up too easily.
 
I've been collecting fuses for about 40 years, but I've never seen a 17 Bm in green. Harry
 
I've been collecting fuses for about 40 years, but I've never seen a 17 Bm in green. Harry

Hallo Harry,
I also have never seen this fuze in green colour. But, it's a Z.17 Am, very long delay. Yesterday I read in a 1944 Luftwaffe Manual. There it says, that the 17 Bm was originally ment for "Special Munitions", but, by that time (1944) it is mainly used for demolition purposes. I have seen many fotos, over the years, taken in the endphase of WW2, where places (roadcrossings, bridges, mainroads) had been prepared for demolition with a "grave" dug up and a "Luftwaffe"-bomb laid in horizontally. For this purpose both the 17 Bm for very hasty retreat and the 17 Am for slower retreat, are ideally suited. The bomb can ly in its grave all ready fuzed with a rope attached, which only needs to be pulled to start the delay. The manual warns, that if this fuze is used in bombs 2 additional booster-pellets have to be inserted first, because these fuzes are shorter than normal electric bomb fuzes.
Greetings,
Bellifortis.
 
After reading this thread, and seeing the pictures, I am a bit confused. What I understand is that there were two different fuzes, a Langzeitzünder (17)Am for aerial bombs, and a Langzeitzünder (17)Bm for demolition. Correct?

If so, are all the red fuzes shown above the Langzeitzünder (17)Am, and only the green one shown by millsbomber is a Langzeitzünder (17)Bm? Or are they both identical from the outside?

Also, did the Langzeitzünder (17)Bm still use the same set-up with the gaine like the Langzeitzünder (17)Am aerial fuze used, even though it was being used for dempolition?
 
Hi @WWIIbuff,
originally these fuzes were designed for "Special" Air force munitions, like the V1, where it was used as a safety-fuze to insure detonation even if all other electrical fuzes failed. But already in 1944 it was used mainly for demolition purposes. There were a lot of german airial bombs around that were not needed any more. The difference between (17) Am and Bm is only in time-delay of the clockwork. Am was 2-72 hours and Bm up to 120 minutes. I hope that this clarifies the differnces.
regards,
Bellifortis.
 
Thanks Bellifortis! :) So the exterior appearance of the two would be the same, only the internal clock settings would be different. Was the gain still attached to the bottom when used for demolitions purposes?
 
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