Early German proximity fuse

Discussion in 'Alternate History Discussion: After 1900' started by wiking, Sep 16, 2011.

  1. wiking Well-Known Member

    Jan 19, 2006
    Note: This is not about a late war German victory scenario or even a stalemate, just a discussion of the effect of a technology appearing earlier in the war.
    Wikipedia has some interesting information about the German Proximity Fuse project. Apparently by the end of the war 1000 units had been successfully test fired before the project was cancelled due to the facilities being overrun. Not only that, but by Führerbefehl the project was cancelled in 1940 due to not being ready within 6 months and not restarted until 1944. Roughly within 15 months of being restarted the Germans had a functional Proximity Fuse ready for mass production. So what if the project was not cancelled in 1940 and the fuse was ready by the end of 1943 for mass deployment? I realize of course this requires some handwaving to get Hitler to change his mind and some allowance for technological developments that had occurred between 1940-1944 OTL that would have aided a quicker development of the Proximity Fuse project starting later. For that reason I had development take longer than 15 months ITTL and do require some suspension of disbelief, though I should mention the US had their VT fuses ready in 1943 and only started the project in 1940 (with some British help, having started their project in the late 1930’s), whereas the Germans had been working on theirs since the mid-1930’s.
    So what does this mean for the air war from late 1943 on? From historical experience the US claimed effectiveness was 3-4x greater with the Proxy Fuse. Germany also had a more experienced and effective Flak force in 1943 than the Americans. Also the German reliability for their historically tested fuses, fired at a metal wire, were 95% within the ‘kill’ range of the 88mm shell’s explosion. Also the Germans used an electrostatic sensor for their shells, unlike the US, who used radio detection, which made the German shells very difficult to jam, even for Chaff. The major problem would be directing the Flak guns to target the right piece of sky, which is where the Germans did have some trouble given the large numbers of batteries and training the right personnel for fire direction.
    Still with a 3-4 fold increase (US experience) in destruction, which may actually be higher in this scenario, as the US and Germans were shooting at different targets in different scenarios (US was using them against Kamakazis, while the Germans were shooting at slower, more bunched heavy bombers, which were larger targets and more vulnerable in formation flying), the Germans could very well put the Allies above the sustainable loss rate and force a stop to daylight and potentially nighttime bombing. This prevents the dispersal of German factories, prevents damage to German industry and worker, prevents the destruction of rail infrastructure, and the destruction of German synthetic oil facilities, while also preventing the mining of the Danube by air and the heavy reduction of oil imports from Romania. Also, once the fuses could be mass produced, the flakwagons of the army could have a much more effective weapon for fighting fighter-bombers that stalked and caused so much damage to the German ground forces. These could also be used for airfield defense and against Flak suppression raids by the Mosquitos, which would probably become the go-to bomber for missions, thanks to their high speeds and potential to outrun Flak concentrations.
    Does this prevent D-Day or at least change the ability of the Allies to breakout of Normandy? What about the use of the Proximity Fuse for artillery and to create accurate airbursts against targets that cannot be properly spotted? The fuse is also adaptable for rockets and mortar rounds too. Could the R4M and later Wasserfall rockets become that much more effective with this fuse?
  2. Mostlyharmless Well-Known Member

    Aug 23, 2008
    A serious problem is whether to believe Wikipedia. The issue is whether the “CIOS report ITEM no 3 file no XXVI -1 (1945)” actually existed. At Warship Projects Discussion Boards someone posting as Seer Stuart seems fairly confident that it never existed.

    More generally, it would be much easier to develop a proximity fuse for a rocket than for a shell because the shell is rapidly accelerated and spun. It is also likely that German artillery would benefit more than the USN from a working proximity fuse because the system for setting the time delay of the 88 mm was less automated. This is possibly why the Germans contemplated and tested simply using impact fuses as the higher rate of fire compensated for the lower probability of a kill per shell. This is mentioned in “The Foresight War” by our own Tony Williams who might respond to a PM with more details.
  3. Gunnarnz Well-Known Member

    Jan 15, 2011
    I'm not quite sure what an electrostatic fuse is, but looking at wikipedia indicates it might have something to do with charge differentials - presumably aircraft and/or their electrical systems have a detectable one. However I'm not sure this will be able to be used for artillery proximity fuses. Modern proximity fuses use radar to detonate at the appropriate height above ground level, but if the "electrostatic" fuse can't detect that (in the absence of an electrical system, for example) it won't be any help at all.
  4. wiking Well-Known Member

    Jan 19, 2006
    Did he give any basis for that conclusion?
    I have encountered the CIOS, the joint British-American scientific intelligence teams roving Germany in the later stages of the war and immediately thereafter, in other texts with similar citations.

    As to the USN issue, yes that does make considerable sense. I have seen a discussion over at Axis History Forum about the benefits of the contact fuse with an end time fuse to burst contact shells before they could return to ground. I suppose fire direction would be more important to improve the 'kill rates'.

    At least the German low-level Flak units posted with the army to defend against fighter-bombers would receive a major boost, both against the Sturmovik and the various Western 'Jabos'. That situation is nearly the same as the USN experience.

    I understand the critique, but the tests, assuming of course that they were conducted, were used against a metal cable and were able to burst within 10 feet of it, so it stands to reason that metal guns, helmets, and tanks (plus other metal vehicles) could detonate the fuse just as readily.
    Last edited: Sep 17, 2011
  5. Mostlyharmless Well-Known Member

    Aug 23, 2008
    I would suggest that you contact Seer Stuart. He sent me a PM saying that he had an index and that CIOS report XXVI -1 (1945) called "The German artillery proximity fuse" was not listed. I have not seen the index and there may of course simply be an error in either the title or the index. There was mention of an index on an old thread at http://www.lwag.org/forums/showthread.php?p=24355 and there are some reports listed at http://www.fischer-tropsch.org/indexes/cios_rpt_itm21_index.pdf and at http://www.cdvandt.org/cios.htm. However those are only a sparse sampling. A real problem for the credibility of this information is the mention of Igor Witkowski, who is not taken as an authority by everyone http://forum.axishistory.com/viewtopic.php?t=50624&start=45 and http://en.wikipedia.org/wiki/Igor_Witkowski. Thus it would be nice if someone who believed that they had access to such a report would give enough details such as the name(s) of the author(s) to enable someone else to find it. There is a fine collection of doubtful data available on related topics http://skeptica.dk/artikler/?p=8267 although one should perhaps not confuse Kuhglocke(n) with Kugelblitz:confused:.
  6. Gunnarnz Well-Known Member

    Jan 15, 2011
    If I understand correctly, low-level flak was mostly lighter calibre autocannons - 20mm and 37mm were common calibres, I seem to recall. Getting a proximity fuse to work in such a small projectile is not trivial, and I'm not sure it's even possible today. There's also the issue that some AA shells do their damage by exploding near the target, others are so small that a direct hit is required to harm the target. A proximity fused 20mm shell, if such a thing is possible, might not have much of an effect if it went off 10' away. In short, there's probably a minimum practical size for a shell with a proximity fuse.
    It may also be relevant that the rate of fire of autocannons is high compared to a manually loaded gun. Using prox-fused shells would require an extremely large number available, increasing the cost and manufacturing resources involved.
    Finally, there are some differences in the tactical situations the USN used AA weapons in vs that in western Europe. The USN generally didn't have to worry about terrain blocking their lines of sight and fire, for example. There are similarities, but I'd be cautious about claiming the situations were effectively identical.

    As for the cable causing detonation, I suspect it may have been carrying an electrical current when it caused the detonation (this would fit with the 'electrostatic' description of the fuse). Metal guns and helmets generally won't - vehicles with active electrical systems would, of course, but that is less useful than you might think. Air bursts, like artillery in general, are best against soft targets such as infantry. Armoured vehicles usually require very close explosions or (better yet) direct hits, which proximity fuses won't help with - by the time the shell is close enough to damage the vehicle, it's going to hit the ground and be detonated anyway.
    I think we need to know more about how the fuse works before I'm willing to sign off on it being effective as a means of causing artillery airbursts.
  7. phx1138 Bocagiste troll

    Jun 20, 2009
    Charlie Townsend's guest house
    A complete stop is just not on. Domestic politics means Winston has to keep the bombers flying to retaliate. The Brits will have to change tactics. To what, I'm less sure.
    I have my doubts they could "prevent" this entirely, proximity fuse or no. And if the Brits could mine the Danube at all, they had the ability to change approach & mine elsewhere...& the Germans could not defend every mile of river & canal in Occupied Europe.:eek:
  8. cortz#9 Obrltnt of Kampfgruppe Seelöw

    Mar 14, 2011
    From German Secret Weapons of the Second World War by Ian V. Hogg. Quote: Kranich and Fuchs, a radio operated fuze, are generally thought to have been the two German proximity fuze developments which stood a reasonable chance of working in actual service conditions. It has to be said that compared to the Allied development of a fuze to be launched in the far less stressed environment of a guided missile was a much simpler task, and had the Germans begun their work as the same time as the British (1940) they would undoubtedly have had a working fuze in use by 1944. But Kranich and Fuchs were only the tip of the proximity fuze iceberg; there were something like 35 proximity fuze projects unearthed by investigators after the war, almost all for aircraft or anti-aircraft missiles