German airburst fuzes?

Discussion in 'Weapons, Technology & Equipment' started by Chris C, Sep 22, 2019.

  1. Uncle Target

    Uncle Target Mist over Dartmoor

    I'm surprised no one has mentioned Meteorological conditions which have profound effects on range and accuracy. Even more so at high trajectory on AA or field guns at Upper Register in the mountains.
     
    Last edited: Sep 24, 2019
  2. Gary Kennedy

    Gary Kennedy Member

    I did find a couple of references to 'tree bursts' in US Twelfth Army Group 'Battle Experiences'.

    Notes on woods fighting..."when halting temporarily each man should get close to a large tree as this affords some protection from tree bursts. The danger from tree bursts is somewhat lessened by the enemy's lack of observation".

    Artillery Section questionnaire ETO..."Have infantry advances through woods been supported by attempts to obtain tree bursts?"...

    "No. We try to prevent them, for the enemy is usually dug in with overhead cover. Our air bursts are therefore ineffective against them, but sometimes cause casualties among our own men. We use delay fuze to get close to the ground." VII Corps Arty, 79th Div Arty, 333rd Fd Arty Gp and 194th FA Gp.

    "Yes, generally. Delay fuze is sometimes used in heavily wooded areas." VIII Corps and XV Corps Arty and multiple FA Gps and Div Artys.

    Gary

    * I seem to recall Mythbusters doing an episode that included a experiment of the effect on wooden splinters in a high seas cannon battle. I can't recall exactly how it went but I don't think it was good for the 'analogue' pirate crew...

    Gary
     
  3. Sheldrake

    Sheldrake All over the place....

    There is a fairly comprehensive and readable account of British artillery ammunition on Nigel Evans' excellent website. AMMUNITION Well worth reading before posting on this thread.

    Field artillery ammunition isn't as sexy a subject as field artillery equipment, and receiveds far less attention that every nuance anti tank weaponry. The topic barely receives a mention in books claiming to cover "The Guns of Germany 1939-45. It is the ammunition which is the artillery's weapon and there are differences in capability. It is not true that a shell is a shell or that of a British 25 pounder is the same as a German 105mm.

    There were four ways of creating an airburst effect.

    1. A mechanical time fuse - a mechanical (clockwork or ball race) timer
    2. A gunpowder trail time fuse. Less accurate and shorter ranged than a mechanical fuze- but cheaper.
    3. A radar fuse (Proximity or variable time) Only a rich country could throw away a radar with each round, and hidden from the Germans until December 1944.
    4. Fire a high velocity gun at a low angle with a HE graze fuse set to delay. This would work on hard ground at modest ranges.

    The US Army special intelligence series No 10 pamphlet on German AA Guns dated Feb 1943 lists three type of ammuntion for the the 88mm dual purpose gun including HE fused clockwork-time as well as an HE Percussion fuse. Unsurprisingly, the 88mm AA gun can fire airburst. Despite Pickert's comments it was airburst "88" that were loathed by the British. That may have been airburst 7.62 cm or 10.5 cm.

    I am not sure what fuses were provided for German field artillery, whether Time (gunpowder) or clockwork and what proportion of each.
     
    Last edited: Sep 24, 2019
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  4. Sheldrake

    Sheldrake All over the place....

    Here is some information on common German fuses, from British war-time publications

    Time and Percussion Fuze Dopp Z s/60
    Handbook of Enemy Ammunition, Pamphlet No. 1; Dopp.Z. S/60 s.
    Handbook of Enemy Ammunition, Part. 10; German Mechanical Time and Percussion Fuze S/60s (Dopp.Z. S/60s)
    Time and percussion means it will function either after the set time or on impact Max fuse length 60 secs. Used by 10.5cm FH or 15cm sFH to deliver "airburst" effects.

    Mechanical time fuze Zt. Z. s/30# This was the standard heavy AA Fuse
    Handbook of Enemy Ammunition, Part 8; German Mechanical Time Fuze S/30 (Zt.Z. S/30)
    Handbook of Enemy Ammunition, Part 6: German, Fuze, Time, Mechanical, S/30
    This was a mechanical time fuse with no percussion action. It was designed for AA use. You don't want AA rounds that don't action on time to explode on (Friendly) ground. If the Germans used this ammunition in the ground role, the fuses would not action if the rounds impacted before the set time. This may explain the incidents of high numbers of blinds attributed to sabotage in factories. It also made it hard to spot fall of shot. Pickert's comments on ground use need to read with this knowledge. The British had similar problems using the 3.7" AA gun in the ground role.

    German percussion fuze, AZ. 23 Rh.S. The point detonating and graze fuse used by 10.5 cm FH, 15 cm sFH. a similar fuse is used by the 7.5 cm tank guns
    Handbook of Enemy Ammunition, Pamphlet No. 1; AZ. 23 Rh.S. (0.25)

    The fact that the Germans had these fuses did not necessarily mean that every battery had stocks of every type of fuse. The standard was probably HE point detonating with a percentage of Time fuzes that would need to be fitted separately before firing a time (airburst) mission.

    As mentioned above Heavy AA units typically were supplied with a mix of AP, (for hard targets) HE point detonating (for soft ground targets) and HE fused Time for AA Use. In 1940 about a 1/3 of each, because they expected to have air superiority. In Normandy, they were likely to have been supplied a higher proportion of AA..
     
    Last edited: Sep 25, 2019
  5. timuk

    timuk Well-Known Member

    Just to clarify. Percussion fuzes were activated by impact on the striker plate (button on the nose) causing the firing pin to strike the detonator and explode the fuze. Safety caps were fitted and removed before loading. Deceleration of the shell in flight merely caused the fuze to become armed. Good examples and diagrams can be seen here:
    http://www.ammunitionpages.com/categories.php?cat_id=162

    Tim
     
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  6. Uncle Target

    Uncle Target Mist over Dartmoor

    Thanks for clarifying that, I was beginning to worry that I was considered to be romanticising. (That's an old fashioned phrase for telling porkies).
    During firing on training ranges all shells fired were/are counted and their impact observed. A report was generated regarding unobserved shot, which might have either failed to detonate or overshot the designated area, behind a hill etc.
    The ranges were then cleared by RE to remove any unexploded ordnance. Safety was always a key concern but the non removal of the Safety Cap could be considered hazardous to the men clearing them up. I once sat on a hillside on an old Artillery range watching RE digging out unexploded shells, stacking them, applying explosive then blowing them up. Several still had the Safety Cap on but the earth was soft enough to not cause detonation on impact. The reverse was said when in Tunisia at Banana Ridge a Panzer 111 was totally destroyed with a percussion shell at 5-7 Yards which with the Safety Cap purposely left on. The gun was well camouflaged at night, the tank passed in front of it. The shell penetrated the side armour and exploded within the body of the tank with no survivors. The gun crew were taken prisoner by supporting infantry but most of them escaped at the fall of Tunis.
    Catching the side of the breech when loading could also be described as hazardous, with a hefty Sergeant No1 or an IG behind you!
     
  7. Sheldrake

    Sheldrake All over the place....

    Have a look here AMMUNITION

    The British drew a distinction between Direct Action and Graze types of percussion fuze. A Direct Action fuze has to hit something, and a safety cap was removed as part of the arming process. A further safety measure could be the acceleration of firing which armed the fuse in flight.

    Direct action will go bang only if the fuse hits something solid. It is very quick to act, reducing the size of craters cratering, but will create blinds at low angles of incidence.

    Graze action works by violent deceleration and will work at low angles of incidence. However, it is slower to act and will create more craters than direct action (and a worse splinter pattern, as the round is likely to be further in the ground when the fuze functions.

    Some fuzes combined direct action and graze and offered a delay option.
     
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  8. timuk

    timuk Well-Known Member

    Thanks and I quite agree with you. Being ex-RN my knowledge of military fuzes is somewhat elementary although there is a lot of common ground. I was referring to the standard DA percussion fuze, such as the Type 117, merely to show that it was not only Loony Tunes that had a striker/button on the nose. Two safety measures incorporated in arming, one to free the striker, the second to align the detonator (this occurs when deceleration allows centrifugal force to take over from friction).

    Handbook of Current British Land Service Fuzes, 1962, Inspector of Armaments, Woolwich
    Fuze DA 117
    "The safety cap must remain screwed to the fuse until immediately before loading, when it will be removed.
    On firing, - The acceleration of the shell in the bore of the gun causes the arming sleeve to set back and compress the arming spring between itself and the base of the upper cavity of the body. This movement uncovers the segments and, combined with the slight set back of the striker, releases the four segments and permits them to fall clear. Should acceleration not displace the segments they will be positively displaced by centrifugal force. During flight. - As deceleration sets in the striker spring, which is assembled under compression, reasserts itself against the striker head, forcing the striker and striker sleeve forward until the sleeve meets the end of the boss of the guide bush, thereby withdrawing the point of the striker from its recess in the locking weight. This frees the locking weight which revolves on its hinge pin under the action of centrifugal force and, through the medium of its toe, starts the shutter revolving on its hinge pin to the armed position. The shutter is so shaped that centrifugal force can only cause it to revolve gently, the locking weight supplying the initial force. The shutter continues to revolve until it reaches the stop pin which locates the detonator under the striker point. In this way shock to the detonator is avoided when the shutter moves to the armed position. The fuse is now fully armed, the striker point being held clear of the detonator by the striker spring".
    On the subject of graze fuzes I would only add that they often incorporated a time fuze particularly in the case of AA when an unexploded shell could have very unfortunate consequences when it fell to earth!!

    Tim
     
    Last edited: Sep 26, 2019
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  9. Sheldrake

    Sheldrake All over the place....

    Tim my dear ancient mariner,

    AA Fuses for heavy AA guns not include Percussion mechanism for the reasons you have given. The standard British HAA fuse was the 207 fuse which was Time only. I think I explained this in post #24 for German fuzes
     
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  10. timuk

    timuk Well-Known Member

    The ancient mariner's memory tells him that the Type 207 fuze was also used by the RN.

    Tim
     
  11. CL1

    CL1 116th LAA and 92nd (Loyals) LAA,Royal Artillery

    After the Battle no 4 Battle of the Bulge
    Mention of Americans used new proximity fuses for the first time which caused the Germans to panic.
    upload_2023-1-2_19-53-8.jpeg
     

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