German ELAZ 17 Bomb Fuze question

[John D. Bartleson Jr.]

To our german Bomb fuze members,

The early #17 fuzes were stopped by the magnetic clock stopper.
I am told or have read somewhere that a later model had its clockwork located lower in the fuze body and could not be stopped in this manner.
Is this true? Was the drill and inject adopted to stop tihis model?
If the above is true, then what year did the deep located clockwork come into service.
Was it after May 1941?
What was the model designation?
Best Regards,
John

[John D. Bartleson Jr.]

Waff,
Do you have an answer for this?
John

[butterfly]

Hi John,

I think the location of the clock in a 17 described as being lower, possibly refers to it being below the electrical part of the fuze and so deeper in the body of the bomb. The early 17's had a external clock, the later ones 17A had an internal clock, however the difference in relation to the depth was the same.

The magnetic clock stopper continued to be used on the 17's but was not a permanent solution because as soon as the clockstopper was removed the clock restarted. Also there were huge difficulties in removing a bomb from a shaft with the clockstopper in situ.
Thus development continued into a permanent solution and this came in the form of the Stevens Stopper in which a sugar solution was injected via a vacuum into the clockwork and thus clogging it up stopping the clock.

hope this helps.......maybe other members could add a more detailed explination

regards Kev

[John D. Bartleson Jr.]

Thank you Kev,
Let me ask two questions. Would the clock stopper stop the fuze having its clockwork below the electronics?
and what was its ELAz designation?
Second, do you know when the deep fuze came into service?
I have often wondered why the #17 was not drilled throught its top with a drill stop and injected with a fast setting epoxy. That would have solved its problem.
Thanks again for your kind reply. I would have thought everyone would have jumped on this one.
Take care,
John

[waffenamt]

Waff,
Do you have an answer for this?
John

Hi John,
Im so sorry i have missed this thread but i am a little busy renovating the house and running 2 jobs.

Thankfully Kev has bailed me with the great write up.

cheers

waff

[butterfly]

The clockstopper worked fine on the 17 fuze, the trouble was that the Germans would use a 17 with a type 50 fuze. The type 50 was a very sensitive fuze and so had to be dealt with before the clockstopper could be introduced to the ticking 17, in which time the clock may run down and the bomb explode.

The Stevens Stopper did use the method you describe in that a hole was drilled into the fuze head, a vacuum created and a sugar solution injected to stop the clock. This could also be done first before dealing with the type 50.

The type 17 was used in the UK for the first time in 1940, though development was before this - 1939?

regards Kev

[butterfly]

Here are one or two facts that may interest you regarding this.....

the type 50 fuze underwent tests it was revealed that a movement of 0.006 in (0.15mm) in a time of 0,025 seconds was enough to operate the fuze.

the clockstopper weighed 180lb (81.5kg) - a lightweight version was developed this weighed 90lb (40.75kg)

regards Kev

[John D. Bartleson Jr.]

Still no idea of my questions??
John

[millsbomber]

Hello John,
The ELAz designation for the early 17 was EL.A.Z. 17 this one had the clock screwed into the bottom of the fuse its designation was LZtZus Z 17, so the first type really had two designation numbers as it was in two parts, the first picture shows the 17 in 2 parts and the second is with a 17A on the right, the 17 is slightly longer but the clock stopper magnet would have stopped all the types of 17 fuses so that thy could have been rendered safe with the sugar solution method but as Kev has mentioned there was nearly always a 50 fuse in the second pocked of the bomb and possibly a Zus 40 under either of these fuses, with this type of set up the only purpose was to get the Bomb disposal guys.

HPIM6448.jpg HPIM6449.jpg

Dave

[John D. Bartleson Jr.]

Thank you to Kev and Dave,
That really answers my question, in that the clock stopper would have stopped both models.
The reason I asked this possibly dumb question is why did the John Howard 250 kg bomb detonate at Erith?
It most certainly had a #50 in the second fuze pocket which would have been immunized prior to dealing with the #17 and moving it to Erith.
The accident report states that the Earl had heard ticking and called for a clockstopper which had been placed and a sethoscope watch established, afterwich the bomb detonated killing all those poor souls. This question has plagued me ever since I read the incident report last year.
I wonder if the BD officer that originally dealt with this bomb is still living and where the bomb was originally found? Puzzling.....
Best Regards,
John