# Could proximity fuses have halted the bomber offensive against Germany in 1944?



## pattle (Jul 5, 2013)

Germany was only still developing the proximity fuse at wars end after its development had been interrupted by a Hitler order around 1941. The proximity fuse was used with great effect by the Allies, most notably against the V1 flying bombs against which it was highly successful. The Americans were very mindful of the Germans reverse engineering proximity fuses and would at first not allow their use over enemy held territory through fear of a dud being captured. Proximity fuses were later used against ground targets with devastating effect and are generally considered to be one of the major inventions to come out of World War Two.
German anti aircraft batteries concentrated their fire into a box and relied on timed fuses which were timed to exploded at a pre-determined altitude with the hope and expectation that shell splinters would destroy the oncoming enemy aircraft. If the Germans had of had proximity fuses fitted to their anti-aircraft shells then presumably this would have made them far more effective as the fuse itself would have exploded the shell upon detecting the presence of a bomber. 
Obviously the Allies had seen for themselves just how effective proximity fused shells were against the fast moving flying bombs and they would have been more than a bit concerned about the safety of their slow moving four engine bombers should the Germans had developed their own.


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## Civettone (Jul 5, 2013)

I predict some people will come up with the result of American studies on the efficiency of VT fuses in the Pacific or in use against the V1s. These conclude that effectiveness was 3-4 times greater with the Proxy Fuse. But those studies are questionnable. 

Anyway, the Germans were developing a whole range of proxy fuses. By 1945, they were ready to produce them, but they came too late. Also, we have no idea how reliable these would have been. Most (if not all) were designed for use on missiles/rockets, which is quite different from cannon shells. 

The Americans had developed counter measures against proxy fuses. Worked quite well against their own radio fuses, but the German shells worked differently. Some say there was a German flak electrostatic sensor.

Also, German flak effectiveness increased greatly when they stopped using barrage tactics, i.e. bombing at an imaginary box over the target. 

My take is that the best use for these proxy fuses would be on the Enzian air defence missile, which due to its much larger warhead was more effective than the other Fla-Raketen in development.

Kris


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## pattle (Jul 5, 2013)

I don't think we will see a stampede of posts on this topic, fuses are after all not the most glamorous or interesting of subjects although it is often the less glamorous of inventions that have the biggest impact. I personally have no idea how much difference German possession of VT or any other type of Proximity fuse in 1943 or 44 would have made but I feel they would certainly have made life more difficult for the bomber crews and infantry alike.


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## GregP (Jul 5, 2013)

I worked on proximity fuzes for Motorola in the 1980's and they could not have been used in artillery shells in WWII. The circuit components would not survive the positive 5,000-g push and the negative 8,500-g stop when the copper lands hit the rifling groves. Tubes just aren't going to take it. It took transistors to survive the g-load of gunfire.

Two of the prox fuzes I worked on were 6-inch and 8-inch projectiles. We shot them down a 150-foot air cannon into a solid kiln-dried plywood block about a 30 inches square with 100+ pounds of lead plate behind it for recoil absorption. Virtually none were damaged tubes would have turned into glass powder with metal bits in it.

Solid state didn't get around to existence until Bardeen, Brattain, and Shockley invented the transistor in 1947. It didn't result in anything much useful until the early 1950's and artillery proximity fuzes were still a decade or more away.

Would NOT have been possible for a German 88 or any other gun to have a proximity fuxe in WWII. Rockets and missiles? Yes. MUCH less acceleration, all in one direction, and not fueled by a gunpowder explosion. Tubes would survive.

Prox fuzes are essentially a small radar set inside the nose of a projectile with the ability to detect range to target. When the range gets into the proper interval, a fire pulse is initiated and the detonator exercises the warhead or explosive cargo.


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## Milosh (Jul 5, 2013)

Proximity fuse were used in the Battle of the Bulge.

wiki
The Pentagon had decided it was too dangerous to have a fuze fall into German hands because they might reverse engineer it and create a weapon that would destroy the Allied bombers, or at least find a way to jam the radio signals. Therefore they refused to allow the Allied artillery use of the fuzes in 1944. But General Dwight D. Eisenhower protested vehemently and demanded he be allowed to use the fuzes. He prevailed and the VT fuzes were first used in the Battle of the Bulge in December 1944, when they made the Allied artillery far more devastating, as all the shells now exploded just before hitting the ground. It decimated German divisions caught in the open. The Germans felt safe from timed fire because they thought that the bad weather would prevent accurate observation. The effectiveness of the new VT fused shells exploding in mid-air, on exposed personnel, caused a minor mutiny when German soldiers started refusing orders to move out of their bunkers during an artillery attack. U.S. General George S. Patton said that the introduction of the proximity fuze required a full revision of the tactics of land warfare.

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## GregP (Jul 6, 2013)

Would be interesting to see what could withstand the g-force in 1945 .... I have built stuff with that vintage parts and it isn't very durable when you talk about thousands of g's. I'd disbeileve it unless it was mechanical with something a broomstick sticking out of the shell nose ... we did that in Vietnam to get through the jungle canopy.

Without a shematic and the projected parts list, I say BS. Must be somethinhg simple and mechanical or a fabrication. No way tubes can do it. If nothing else, the filaments won't take 5,000 g-s much less more.


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## Greyman (Jul 6, 2013)

I'm not sure what you're saying. Are you calling 'BS' on proximity fuze development and use in WWII?


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## nincomp (Jul 6, 2013)

A film about WWII VT fuses

_View: https://www.youtube.com/watch?v=6-D592VR4RU_

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## GregP (Jul 6, 2013)

Doesn't tell us anything at all about the fuze. Maybe they cobbled together some back to back Flemming valves (an early diode) to make something, but I'm still wondering what the amplifier was. Wiki says it was a Thyrotron trigger, which is a tube.

Perhaps they made 5.000+-g rugged tubes in WWII, but all the tubes we tested in the early 1980's didn't survive gunshot shock. None.

I surmise they had to have made rugged tubes since either solid state was invented earlier than history says or they made gun-rugged tubes. Of the two choices, military gun-rugged tubes seem more realistic.

I've never seen one myself (34+ years in electronic engineering) but, considering the evidence, there must be a way to do it since they could NOT have a prox fuze without an amplifier for the transmit function. I have 10+ prox fuzes in my collection, but ALL are solid state and I have not sectioned them. The only "early" prox fuze I ever saw was whole, not cutaway, and the circuit wasn't described ... just the effect of the function on the artillery shell.

Must be so, but have never seen a gun-rugged tube ... go figure.

Makes me wonder how far the bow and arrow could be developed, actually using a bowstring.

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## cherry blossom (Jul 6, 2013)

The problem of making a useful proximity fuse in WW2 was that you needed a thermionic valve (vacuum tube in US English) which would survive firing. The USA was the only country able to produce these and the reason was because they had previously designed miniature valves for use in hearing aids. There is a history of the development at http://www.history.navy.mil/faqs/faq96-1.htm#anchor1191745. 

The British and the Germans both started the development of proximity fuses but neither could produce valves which could reliably survive firing. Some of the British ideas may have helped the American effort although it started and continued mostly independently. The Germans may have been testing proximity fuses by 1945 and they certainly could have fitted fuses to rockets which did not need to survive such high acceleration.

I suspect that the US reluctance to use proximity fuse where they might fall into enemy hands was not solely due to fear of them being copied. It is possible that ECM could have made American fuses ineffective. I have read that in the Okinawa Campaign, the US Navy had some problems after the US Army installed interfering radars on Okinawa. Thus it has been suggested that post-war development moved towards the German electrostatic fuses.

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## Tante Ju (Jul 6, 2013)

I do not think VT fuses would have made any difference against high flying bombers, those are very different targets than V1/PTO kamikazes. Better Flak guns with better ballistics would help a whole lot more...

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## pattle (Jul 6, 2013)

nincomp said:


> A film about WWII VT fuses
> 
> _View: https://www.youtube.com/watch?v=6-D592VR4RU_



Thanks for the link, that was a really interesting video and a bit of an eye opener for me.


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## delcyros (Jul 6, 2013)

CIOS report ITEM nos 3 file nos XXVI -1 (1945) contains information about german proximity fuses in ww2.
Also files from Rheinmetall-Borsig contain informations.

The proxy fuse project for AAA was designated either Kuhglöckchen (88mm) or Kuhglocke (128mm) and suppsoedly was based upon electrostatic principles. Trial firing carried out in Kummersdorf was effective. Series production scheduled march 45 but never executed.

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## Civettone (Jul 6, 2013)

Delcyros, some say that CIOS report is bogus. I read somewhere that all these CIOS reports are listed, except that one ...


GregP, does a fuse with electrostatic sensor also require a transistor?


Kris


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## OldSkeptic (Jul 6, 2013)

Then short answer is "yes". If you look at the improved performance of proximity fuses when they were introduced against the V1s then you could easily extrapolate to an significant improvement in the effectiveness of German flak. In fact you would expect it to be far greater, in that PFs used against V1s had only a short engagement time (due to low altitude and speed), against slow and high 'heavies' (both night and day) you would expect considerably better performance. Possibly to the point where operations against targets that had them would have had to have been curtailed.

Bomber Command would have been put out of the area bombing business for example.

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## GregP (Jul 6, 2013)

I've worked on radar fuzes but not electrostatic fuzes. I don't see how an electrostatic circuit of 1940's vintage would detect an uncharged aircraft or even the ground, but it could be. I won't say no to it, but remain skeptical unless I could see the circuit and know the sensitivity of the detector. 

How would it work against a Mosquito, were the metal was mostly the engines, propellers, engine mounts and landing gear, none of which should be overly charged for any reason.

Why should an electroctatic detector function as it approaches the ground?

You know, they'd roll over and beg for one of our fuzes but, in the absence of smart electronic countermeasures, a continuous wave (CW) device would work just fine. Perhaps pulsed CW. The problem, to me, is still the amplifier for the transmit function. Receiver? No issue. Antenna? No issue. Transmitting after a +5,000 and - 9,000 - g shock? I wonder very hard if tubes are involved. But they had to have made working, gun-rugged amplifiers SOMEHOW or it's all a lie.


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## Jabberwocky (Jul 7, 2013)

The VT radio proximity fuse was produced in a wide variety of Mks through the war, starting with the MK 32 for the US 5 inch gun. Here's an image of the Mk 53 fuse of 1944 vintage:

http://upload.wikimedia.org/wikipedia/commons/b/b7/MK53_fuze.jpg

The British and the US had been working on ruggedising vacuum tubes for a radio proximity fuse from 1939 and 1940, respectively. The US devoted far more resources into it and had a workable fuse in the form of the Mk 32 by early 1942. Work on a photo-electric fuse was abandoned when the solution to the VT fuse was found. 

The US developed the VT fuse through the National Defense Research Committee, specifically Section T of Division A. The US spent more than 1 billion on the research and development and purchase of VT fuses during WW2 and bought more than 22 million fuses.

The technical challenges were immense. Not only did they need to shock harden the tubes, they had to design new types of circuitry, a new type of battery, new filament types ect. 

There's a pretty thorough history here http://www.history.navy.mil/faqs/faq96-1.htm

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## bbear (Jul 7, 2013)

just on the internet:

http://drdo.gov.in/drdo/pub/monographs/Introduction/Proximity_Fuzes.pdf

Radio Proximity Fuzes

I hope those links work - if not the title of the first is Proximity Fuses Theory and Techniques by V K Arora

It's from the indian government, just a snippet of longer work but seems to give more technical detail than anything I've seen so far here and backs up Jabberwocky's chain of events. and is referenced. It makes sense to my rusty electronic mind but.....

the second is a survey of proximity fuses by ed sharpe that I don't think has been mentioned yet and gives the context and significance 

It's only one and a half sources really, but some estimate of the quality might be made? Amongst other items, (I think they may they use the same reference to source 'A. Price 1963 The History of US Electronic Warfare ') during the Battle of the Bulge a munitions store including VT fuses was captured by the Germans - Wright Field in two weeks came up with a lab working ECM solution in case the enemy started using 'copy cat' fuses in their flak. 

So the answer to the first question would be 'yes but no but yes but no...'. In any case thanks to previous bombing German valve production had been hit? Mosquito pin point raid low level if I remember took out one centre

Unfortunately neither source details the valve design which was GregPs question. The 1963 Price reference might clinch it for those with the right access?

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## OldSkeptic (Jul 7, 2013)

Jabberwocky said:


> The VT radio proximity fuse was produced in a wide variety of Mks through the war, starting with the MK 32 for the US 5 inch gun. Here's an image of the Mk 53 fuse of 1944 vintage:
> 
> http://upload.wikimedia.org/wikipedia/commons/b/b7/MK53_fuze.jpg
> 
> ...



Thanks, beat me too it. We tend to have a bit of modern arrogance about what people did in the past, even without the 'magic' of silicon.
A cynic would say "once upon a time people used their brains".

Jabberwocky, you will appreciate this, how good was the Concorde's original analog control system? Superb basically, not changed to digital until long into it's life.

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## OldSkeptic (Jul 7, 2013)

GregP said:


> How would it work against a Mosquito, were the metal was mostly the engines, propellers, engine mounts and landing gear, none of which should be overly charged for any reason.



Not as well basically as against other planes. Short range signal and needs a return signal. If it got close too the engines then fine. Plus it was fast.
Then again the V1 was as fast or faster, and it worked real well against them. Though it was all metal of course.

But against a Lanc, or a B-17 or a B-24 .. ugly.

We were lucky they didn't crack it until too late.

But against a Lanc, or B-17 or B-24 ... would work real well...


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## GregP (Jul 7, 2013)

Nice pic Jabberwockey. 

Everything inside would have been doable ... and I see the oscillator-detector-amplifier-thyatron bundle looks like tubes. Since there is an oscillator, I am assuming either Continuous Wave (CW) or pulsed CW operation, which would make perfect sense because by the time I came along (in the 1980's), everyone knew that CW fuzes could be jammed and we weren't using CW any more. My bet would be simple CW transmission.

In one of the prox fuzes I worked on, there was a circuit with a variable threshold and if it detected jamming, it would raise the threshold until the jamming was overcome or until the circuit would no long work. If threshold circuit was swamped, the fuze guidance would home in on the jammer! The theory was that if you got the jammer, then later missiles, which were assumed, would not have to contend with it. There might be another one or several other jammers. but this particular one would not be functional.

That type of circuitry was simply not available in WWII, particularly an airborne agile jammer. VT was probably a CW fuze. A radar beam goes out, some signal bounces back, when you reach a preset threshold, function the detomator. Except for the tubes, it looks pretty contemporary! They still have impact-activated batteries and the shells still have about the same outline and available volume for the fuze.


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## OldSkeptic (Jul 7, 2013)

Greg it was doable ... because they did it. Like the anti V1 flak and later artillery.


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## pattle (Jul 7, 2013)

OldSkeptic said:


> Then short answer is "yes". If you look at the improved performance of proximity fuses when they were introduced against the V1s then you could easily extrapolate to an significant improvement in the effectiveness of German flak. In fact you would expect it to be far greater, in that PFs used against V1s had only a short engagement time (due to low altitude and speed), against slow and high 'heavies' (both night and day) you would expect considerably better performance. Possibly to the point where operations against targets that had them would have had to have been curtailed.
> 
> Bomber Command would have been put out of the area bombing business for example.



This is the same as what I was thinking. The only two doubts I have is what people are now saying about the possibility of electronic counter measures being used to stop these shells from exploding next to our planes and my knowledge of electronics goes about as far as being able to wire a plug so I have no opinion on how possible this was. The other thing I can't decide on is whether proximity fuses would have been more deadly against the USAAF bombers flying in close formation or the RAF flying in a bomber stream. My own opinion is that I don't think it would have made much difference how the bombers arrived as with a close formation in daylight all the guns would have been firing at once at lots of planes in a small area which they couldn't miss while at night the guns should have been able to pick the bombers off pretty much one by one as they flew past in the bomber stream. I am not sure just how close RAF and USAAF bomber losses already were to being unsustainable but I feel that German use of proximity fuses could have tipped the balance here. 
Just to add one more point if the Germans had of been able to use proximity fuses in the flat open areas of the Steppes then I think the results there may also have tipped the balance.


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## Civettone (Jul 7, 2013)

I wouldn't assume that the proxy fuses were that effective against the V1. There were more factors at play, which make it difficult to assess the fuses seperate from the other factors. 

I haven't seen real evidence that the Germans had proxy fuses for use in artillery shells.

Kris


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## cherry blossom (Jul 7, 2013)

The proximity fuses used in WW2 were easy to jam and a jammer could apparently be produced in only two weeks, admittedly by scientists who knew everything about the fuse that they were jamming. As I mentioned, the fuse could even be accidentally jammed by other radars operating in the area. The British design, using the Doppler shift to find the closest approach might have been more resistant. The jamming resistant German electrostatic approach could have led to at least a patent Patent US3871296 - ELECTROSTATIC PROXIMITY FUSE - Google Patents if not a successful fuze. It would be fun trying to find if the American work post-war developed from German ideas but, alas, we have just missed being able to ask Philip Krupen by two years and Laurence Heilprin died in 1993.


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## pattle (Jul 7, 2013)

Civettone said:


> I wouldn't assume that the proxy fuses were that effective against the V1. There were more factors at play, which make it difficult to assess the fuses seperate from the other factors.
> 
> I haven't seen real evidence that the Germans had proxy fuses for use in artillery shells.
> 
> Kris


I have read that by the end of the war they were on their way so to speak, but they could have been in use much earlier if Hitler hadn't of stopped their development in 1941. I am only surmising as to how they could or whether they could have changed things. As with most what ifs I think this makes an interesting talking point, but that's about all.


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## Conslaw (Jul 9, 2013)

What kind of fuse did the Germans use for their "tree burst" artillery during the Battle of the Bulge?


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## nincomp (Jul 9, 2013)

Conslaw said:


> What kind of fuse did the Germans use for their "tree burst" artillery during the Battle of the Bulge?


I may be mistaken, but I believe that the "tree bursts" were caused when typical shells with contact fuses hit trees and exploded.


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## parsifal (Jul 9, 2013)

hard to know how effective VT fuses were, because the allies were facing a different problem to the germans

The USN investigation into the effectiveness of their flak was that it was responsible for destroying about 2000 Japanese aircraft. Ive seen and read the study, somewhere, but it would take some finding. However that same study estimates that in1942, the average rounds per kill of HAA was about 2500. By 1944, that number had dropped to to an estimated 500 rounds per kill 

For the British throughout the whole of 1940, the claimed AA kills were 400, but in reality it is thought that the number of kills was under 100. That was using basically obsolete guns with virtually no modern gunnery aids.

Throughout 1941-2 the estimated rounds per kill for Genneral Pile's AA command was about 3-5000 heavy rounds per kill. That is almost exactly the same as the Germans, who, according to Westermann were expending around 4000 rounds per kill. This was before the introduction of VT techs. AFAIK, there was not an appreciable increase in efficiency due to the VT techs on conventional a/c. People should however be very careful of this....we dont know if german countermeasures such as Duppel or the tendency of the germans to oerate at night had any effect on Allied AA effectiveness. One would surmise that it was likley to degrade effectiveness, so maybe VT offset these german initiatives. 

At that time (1942) the germans had many advantages...a high percentage of radar directed batteries, fully trained, professional crews, a relatively new an unworn artillery park, and aircraft not able to operate above the effective ceiling of their gun park (about 24000 feet). Importantly also, the germans were not hampered by Allied coiuntermeasures However, by 1944 a number of suignificant things had crept in such that the average RPK had risen to about 12000. Most German batteries were now manned by part timers, German radar performance was significantly downgraded (most AA fire was now no longer directed fire, it was mostly barrage type), there was excessive gun wear in the park (which effectivellowered the effective ceiling to 21K or less and also affected accuracy and increased jams) , and many more aircraft were operating above the effective ceiling of the park. In that environment, I dont see the introduction of a single piece of tech as having much impact on German fortunes at all....


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## OldSkeptic (Jul 9, 2013)

Looking around for some examples of PFs effectiveness we get:

V-1 flying bomb - Wikipedia, the free encyclopedia



> These electronic aids arrived in quantity from June 1944, just as the guns reached their firing positions on the coast. Seventeen percent of all flying bombs entering the coastal 'gun belt' were destroyed by guns in their first week on the coast. This rose to 60% by 23 August and 74% in the last week of the month, when on one day 82% were shot down. The rate improved from one V-1 destroyed for every 2,500 shells fired initially, to one for every 100.



Other technical fixes were introduced at the same time (such as better calculators and faster swivel mounts) so difficult to pin point exactly the difference PFs made, but obviously considerable.
As for countermeasures, people forget the huge numbers of bombers (both RAF and USAAF), fitting every one with a radar countermeasures would have been difficult in the extreme, assuming it could be done of course.
For the tight groups used by the USAAF this might have been counter productive. Even the later (and tighter) RAF bomber streams would have been at risk.
Opened up the chance to use the bombers' own counter measures against it too. The Germans had become very adapt at detecting them from their emissions.

The Germans started developing their PFs quite early on, then cancelled development, they took the path of doing it electrostatically, not sure how you'd countermeasure that.

As for the Germans using them against the high flying RAF and USAAF bombers, they would have made a heck of a difference. You have to remember that as the war went on they were using poorer and poorer trained people (old men, kids, forced labour, etc). They also were hampered (to the best of knowledge) with poor calculators and insufficient radar guides (they had them, but not nearly enough). 

All you'd have to do was get the shells into the bomber group (or stream) and the probability of a hit would have gone up massively. This even more so for the RAF's night bombers, where individual spotting was impossible.

If they had managed to mass produce them for their 88s and 105s (?) then life, as they say, would have got very interesting for the bombers.


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## cherry blossom (Jul 9, 2013)

For comparison, some of you may like to look at the thread Axis History Forum • 1944: Flak Alone Blasts the Allies out of the Sky which I found while looking for information on the German use of contact fuses. The Germans may benefit more than the USN because they were using a less automated fuse setter and thus might be able to increase their rate of fire more. However, they are not shooting at a target approaching them directly, so the problem of getting the shell to the correct place is more difficult. Thus the fuse setting errors may be a smaller proportion of the German problem than the USN's problem


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## Tante Ju (Jul 9, 2013)

OldSkeptic said:


> As for the Germans using them against the high flying RAF and USAAF bombers, they would have made a heck of a difference. You have to remember that as the war went on they were using poorer and poorer trained people (old men, kids, forced labour, etc). They also were hampered (to the best of knowledge) with poor calculators and insufficient radar guides (they had them, but not nearly enough).
> 
> All you'd have to do was get the shells into the bomber group (or stream) and the probability of a hit would have gone up massively. This even more so for the RAF's night bombers, where individual spotting was impossible.



The problem I see is that hampered by inexperienced, part time crews who could not shoot accurately enough. IF you can get the shells into the bomber group, that assumes good accuracy (which is diminished if the target rather out of the effective ceiling of the gun, as any FC errors are magnified) and then normal timed fuses should do. That was actually the major problem, as US bombers flew rather high, quite on the edge for the most common 88s. Now the FC elements could probably calculated rather well, especially for such big formations, but the problem was that the shells took rather long time to get their, which magnified the calculation errors enourmously. Thats why the rarer long 88s, 105s and 128s were so much more effective - they had higher effective range and shorter flight times.

Perhaps a VT fuse would give more consistent results (fuse variations eliminated), but for BOTH fixed-time and variable time fuse has the prequisite is that you need to lob shells close to the target. If you cant get them close, neither will be effective.

The shipborne AAA is bad parallel example, since they had very very different problems to face. Getting a shot near to relatively close range targets on a more or less straight path towards you is easy, but setting the fuse right isn't. VT fuses cured this effectively. This is an exact opoosite of the problems faced by German flak, so I do not think VT fuses would change a lot.


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## swampyankee (Jul 9, 2013)

GregP said:


> Would be interesting to see what could withstand the g-force in 1945 .... I have built stuff with that vintage parts and it isn't very durable when you talk about thousands of g's. I'd disbeileve it unless it was mechanical with something a broomstick sticking out of the shell nose ... we did that in Vietnam to get through the jungle canopy.
> 
> Without a shematic and the projected parts list, I say BS. Must be somethinhg simple and mechanical or a fabrication. No way tubes can do it. If nothing else, the filaments won't take 5,000 g-s much less more.



US proximity fuzes used radio, and tubes. See http://www.history.navy.mil/faqs/faq96-1.htm#anchor1191195

As an aside, George O Smith, the sf writer was said to have worked on this project. A different sf writer, Arthur C Clarke, worked on GCA.


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## delcyros (Jul 26, 2013)

Civettone said:


> Delcyros, some say that CIOS report is bogus. I read somewhere that all these CIOS reports are listed, except that one ...
> 
> 
> GregP, does a fuse with electrostatic sensor also require a transistor?
> ...



Ok, I have taken time to get through it. Actually I couldn´t find a CIOS item, too, and I have generally good access to these sort of documents. However, I guess it may have been a mistake by someone. The reports do indeed exist but the relevant content for Rheinmetall proximity fuses is filed down under the ALSOS files, not under the CIOS ones.

I quote the relevant reports:

Series II----ALSOS-C: 
U.S.Naval technical Mission to Europe Ordenance target No.22 -Report on the proximity fuse development of Rheinmetall-Borsig A.G., June 1945

Series II----ALSOS-E:
U.S.Naval technical Mission to Europe -U.S.Army technical Mission to Europe Fuse reports (files "a" to "f").


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## cherry blossom (Jul 26, 2013)

There is an interesting book, “American Raiders: The Race to Capture the Luftwaffe's Secrets” by Wolfgang W. E. Samuel, available on the internet at ftp://s208.math.msu.su/572000/153b165a481f89e812c6bfee9c12b7be. This seems to relate “Status Report of Exploitation Divison” under a USAAF Brigadier General George C.McDonald. Page 158 has: 

For the Great Enzian and other German surface-to-air missile developments to be effective, a proximity fuze was needed. To no one’s surprise, one of McDonald’s teams reported, “A proximity fuze development for artillery shells has been recovered. It has been ascertained that the fuze operates on electro-static principles and, accordingly, will be a very difficult fuze against which to employ countermeasures. . . .German research had under development no less than fifteen different projects involving proximity fuzes. Although it is evident strict supervision from a central agency should have controlled the related projects, it is now apparent no such control existed and that activities were poorly coordinated. A number of the projects originated in 1930s,were halted in 1940, and revived in 1943 when the danger from air bombardment became more acute. Not a single proximity fuze has seen service, and only two could have been placed in mass production within two years.”22

The reference 22 says: 

22. Status Report of Exploitation Divison, Tab G, pp. 72-73. To obtain optimum results with their surface-to-air missile developments required a proximity fuze or a homing device. According to Post Hostilities Investigation, German Air Defenses, Volume I, page 4, of the four methods of fuzing examined by the Germans—photoelectrical, electrical, acoustic, and infrared—at the end of the war none of the projects had gone past the development stage and no fuze had been developed that was small enough for a flak projectile and could withstand the shock of being fired from a gun. Proximity fuzing coupled to antiaircraft artillery and SAMs was the most cost-effective approach to defeating Allied air superiority, yet only peripheral resources were brought to bear in this important field, an area in which American science excelled.


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## OldSkeptic (Jul 26, 2013)

> On 4 November 1939, Captain Hector Boyes, the Naval Attaché at the British Embassy in Oslo, received an anonymous letter offering him a secret report on the latest German technical developments. To receive the report, he was to arrange for the usual announcement of the BBC World Service's German-language broadcast to be changed to "Hullo, hier ist London". This was done and resulted in the delivery of a parcel a week later, which contained a typewritten document and a type of vacuum tube, *a sensor for a proximity fuze for shells or bombs*. The typewritten document accompanying it became famous after its existence was revealed in 1947 and would go down in history as the "Oslo Report".[1] Boyes quickly appreciated the Report's potential importance and had a member of the embassy staff make a translation which he forwarded to MI6 in London along with the original. The Oslo Report was received with indifference or even disbelief by British Intelligence, with the notable exception of *Dr. R.V. Jones*, a young Ph.D. physicist who had recently been put in charge of a new field called "Scientific Intelligence". *Jones *argued that despite the breadth of information and a few inaccuracies, the technical details were correct and argued that all the electronic systems divulged therein be further explored. In a 1940 report, Jones summarized his thoughts.[2]



Fortunately for us the Germans cancelled it.


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## delcyros (Jul 27, 2013)

I tend not to overemphasize the effect. Remember, the Proximity fuse does not change the problem to get a projectile close to it´s target in the first place- and many do not work at all. It definitely increases efficiency, however.


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## bbear (Aug 7, 2013)

mostly for GregP to comment (quality warning junior at work - it is ii bbear currently 1 sensible comment in 20 attempts - well you did say 'go figure')


thyratron = SN-856-F or close cousin (credit radiomuseum.org ludwell sibley

receiver valve possibly cv122 but in any case linked to US patent US3113235 - RUGGED VACUUM TUBE - Google Patents

original type 32 and 40 patent looks like Patent US3166015 - RADIO FREQUENCY PROXIMITY FUZE - Google Patents

key book : the deadly fuze by Ralph B Baldwin part of the original team (out of print, no I don't have one - going on reputation) 

I have no firm source on how the structural/potting component of the design worked but it feels as if that was the biggest secret. Lucite - 'obsidian appearance' might it be rubber toughened? Valves suspended in rubber 'pots' with polymerised Tung oil or similar as a 'wax' as described in the later 1958 patent? The only thing I can think of is some avoidance or treatment of axial and centrifugal forces to avoid 'bending moments' which would shatter a tube n an 'AAA shell in one orthogonal direction or the other. But the valves must remain fixed with respect to each other according the patent....
More figuring to be done...

Talking of airburst in trees - the british WW1 106 fuse later 115 type in wwii seems to be the original 'setback and centrifugal acceleration manager': sprung loaded hammer knocks forward pin releasing copper tape - result an ultra sensitive contact fuse that arms in flight and detonates with the he/shrapnel just above ground, or on barbed wire, tree twig...

And I think it may not be the straight artillery flak that top brass were most worried about when the Germans captured VT fuses during the Bulge (Wright field didn't take two weeks to develop a jammer/predetonator : reading between the lines it was a two week deadline I think). 

Germany had some good AA rockets that could reach 30,000 ft from surface IIRC (rocket: low setback acceleration no need for fancy vacuum tubes ) and scary glider bomb controls... 2+2 + VT fuse : = no more large formation flying for sure. A bomber carrying the first wright field solution for ECM could also quickly be- a homing beacon 

so my temporary answer to the original question is no it couldn't stop the allies, but it wouldn't have been fun finding out 

btw the video footage quoted above in the thread all seems to use clips from a training aid : Film Bulletin 197 from 1945 which shows the unpacking disassemly adjusting and reassembly of a VT rocket - on you tube , fascinating stuff


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## bbear (Sep 4, 2013)

and here are the links 

Radiomuseum article for Sylvania SN-856-F prototype thyratron 
SN-856-F (SN-856-F)
to save time the links that Mr Sarbell gives for Sylvania general discussion and the best cutaway drawing http://www.radiomuseum.org/forumdata/upload/Sylvania_TechNews_page1.jpg
http://www.radiomuseum.org/forumdata/upload/Sylvania_TechNews_page2.jpg

And an online source from someone who melted off the cerese wax (petroleum product - substitute for original tung oil) potting to reveal the construction
http://www.tubecollector.org/equipment/proximity-fuse.htm

and also gives the reference to british type CV122 or us type 2E27 with 2D29 as a thyratron : tbc

see the construction: tubes are one atop the other in a metal can along the axis and is that a glass fuse I see on the left half hidden

note the support flange is at the top - the electronics unit is suspended from forward in the direction of travel not fixed at the base

the two VT assembled fuzes seem quite different one looks an earlier Lucite type and the other may be post war - i'll need to look

The book 'the deadly fuze' gives hardly any technical detail. It does say the original lucite/plexiglass was replaced by Teflon so that explains the black 'obsidian' appearance of the type 53 and similar later vintage fuses. 


The potting latest hunch: is dense, and either malleable (cerese wax) or low strength crackable (tung oil) at ground temperature and under shock undergoes a 'state change' to fluid (cerese wax melting point is 180F) thus managing the 
set back (rotation and linear) by movement to average the kick out and absorb energy from then on like a shock absorber damper and 
side shock (rotational) - likewise by viscous losses in the fluid and 
steady state centrifugal forces - the lighter valve assembly 'floats' to the centre automatically. Note if the 'can' fits fairly tight to the tubes the microphone effects would be common to all tubes held by the can and the fixed relationship of the tubes is assured as required in one of the patents- 

that may be the sought after 'mechanical assembly' that is referred to but not described in the navy history or other material referenced so far : all surmise of course - just as a clue



and the book gives a few more details on the germans : they did pick up a 'dud' and worked out it was electronic but not what it did. patton called it 'the funny fuse' germans at Bastogne called it 'bauschboom' - puffbang I think. British AA army called it BONZO. Land army 'Air-burst' possibly. US Army mostly called it VT or 'Pozit'

Guided Wasserfall AA rockets might have been the biggest threat - never quite completed but....

I'll edit in the other links later


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## Reegor (Sep 9, 2013)

delcyros said:


> I tend not to overemphasize the effect. Remember, the Proximity fuse does not change the problem to get a projectile close to it´s target in the first place- and many do not work at all. It definitely increases efficiency, however.


 
I must be missing something. It seems to me that a proximity fuse would at least double the kill rate. To be effective, AAA needed to explode a shell inside one of the boxes each containing about 20 aircraft. (This is for combat formations of 8th Air Force bombers.) The problem of firing on a trajectory that intersected a box is not changed. But setting the fuse timing correctly is solved by the Proximity fuse. 

Pkill = P(trajectory that intersects a bomber box) 
x P(shell explodes at same altitude as bomber box, if it passed through the box) 
x P(causes major damage to an aircraft)

The first probability is unchanged. The second probability goes from ? to .99. I can't believe that probability of correct time fusing was more than 50%, and perhaps a lot less.
The third probability increases moderately, since the proximity fuse is designed to explode at the moment of closest approach. 

All together, the effectiveness of German AAA would at least double, and perhaps triple or better. Doubling would be 31% higher overall losses, according to the paragraph below. In 1945, this would not have mattered. But in 1944 it would have been serious, although probably not enough to halt the American attacks. Indirect effects of flak were to reduce bombing accuracy. Since Allied heavy bombing accuracy was so poor to start with, I don't think that proximity fuses would have had much impact on the results of bombing. 



> In comparison to their British counterparts, flak defenses accounted for over half of the USAAF's combat
> losses during the war in Europe, downing almost 5,400 aircraft compared with the 4,300 aircraft shot
> down by Luftwaffe fighters.3
> The Eighth Air Force lost a total of 1,798 aircraft to flak during the war.4
> ...


Source: * Flak: German Anti-aircraft Defenses 1914-1945*
Edward B. Westermann
University Press of Kansas


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## pattle (Sep 9, 2013)

This is just another what if thread so I don't think anyone can say with any certainty what exactly would of happened had the Germans of had access to proximity fuses, but for me one things for sure and that is it would of helped the Germans more than it helped the Allies. Under the circumstances that the Germans were in during late 1944-45 it sounds to me as though proximity fused ground defences would have been a safer bet than Me262's and the other wonder weapons. I think though that the Me262's and jet fighters are in general a far more interesting topic for discussion than boring old artillery fuses and this is why we don't hear so much about them. Nobody looks at a picture of a fuse and says wow.


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## OldSkeptic (Sep 10, 2013)

pattle said:


> This is just another what if thread so I don't think anyone can say with any certainty what exactly would of happened had the Germans of had access to proximity fuses, but for me one things for sure and that is it would of helped the Germans more than it helped the Allies. Under the circumstances that the Germans were in during late 1944-45 it sounds to me as though proximity fused ground defences would have been a safer bet than Me262's and the other wonder weapons. I think though that the Me262's and jet fighters are in general a far more interesting topic for discussion than boring old artillery fuses and this is why we don't hear so much about them. Nobody looks at a picture of a fuse and says wow.



Agree, my take on this is that if the Germans had managed to mass produce (and don't forget, re my earlier post, they had a big head start, ref Oslo Report) a proximity fuse then a lot of the day and night USAAF/RAF long range bombing campaigns would have failed and been called off. With unforeseeable impacts, though some would argue that it would have been better for the Western Allies that way.... just saying.


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## parsifal (Sep 10, 2013)

I have to admit, I am having some second thoughts about this discussion. VT fuses, were valuable, its a question of whether they would make a difference for the German situation


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## JtD (Sep 11, 2013)

If a proximity fuse was devastating, would the Allies cancel the bombing or invent counter measures?


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## stona (Sep 11, 2013)

Nobody convinced me that the proximity fuses would transform Luftwaffe flak into a weapon system capable of devastating allied formations. The Luftwaffe originally thought they needed to get the shell (88mm) within 30m of a bomber to destroy it. This was revised_ down to 3m_. That's the problem. Your projectile needs to pass within 3m of the target to be "devastating" and nothing here has convinced me that this was possible often enough to have a huge effect on allied losses.
Cheers
Steve


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## yulzari (Sep 11, 2013)

If we assume that artillery shell proximity fuses were a task too far for the Luftwaffe, but that rockets could have carried a feasible Luftwaffe proximity fuse then the discussion has looked at the guided rocket projects.

However, could this not be more easily done by unguided air launched rockets? Simply (and I know it is not quite that simple) amend existing air launched rockets to be proximity fused instead of the normal fusing? e.g The Wurfgranate 21 that was in use from mid 1943. Accuracy would be less important so it would be sufficient to launch them at the USAAF 'box' rather than a specific aeroplane and from out of effective range of the .5" defensive bomber guns. In fact a logical response could be to remove the defensive armament to allow the bomber to fly higher and cruise faster to make them more difficult targets, relying on fighter escorts to engage the Luftwaffe fighters.

At night the heavy bomb loads demanded by the RAF left them well within standard 88mm range so an AA proximity fuse would be more to be feared by the RAF. In fact, by the time a night fighter is close enough to identify it's target it is probably close to the damage range of a Wurfgranate 21 warhead and not far off the proximity range of such a fuse.


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## bbear (Sep 11, 2013)

In 1944 Germany would not be able to produce VT fuses for AA. It took a US programme of a scale and duration comparable (smaller but of the same 'heavy weight' category) with the Manhattan project. In the age of glass 'radio tubes' it was extremely difficult. Even if they worked out what the VT fuse did, I doubt that the radio tubes would be that easy to come by and manufacture into rocket fuses. 3-6 moths perhaps?

To explain the level of apparent anxiety in Allied command about the use of VT on the continent - I mentioned ground based guided rockets in daylight - air to air rockets unguided but close range is a better option.


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## pattle (Sep 11, 2013)

The Germans were testing proximity fuses by the end of the war and allegedly they were close to being put into production, that much we know. I don't think this thread requires anyone to be convinced that proxy fuses would have wiped out bombers in such numbers that bombing would have to be abandoned, expecting anyone to be convinced is a little much to ask because it was never put to the test. I think proximity fuses could have caused losses serious enough to suspend the bombing of Germany, when I say could I don't mean would, I just think it possible. I am neither a scientist or a Marshall of the Royal Air Force, my opinion is only based on what little I know through reading for pleasure.

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## parsifal (Sep 11, 2013)

> I don't think this thread requires anyone to be convinced that proxy fuses would have wiped out bombers in such numbers that bombing would have to be abandoned, expecting anyone to be convinced is a little much to ask because it was never put to the test


.


I need convincing, and so does Professor Westermann who wrote the defeinitive English language version on the German flak arm. There were numerous other problems facing the German flak arm, VT fuses would have helped, but I dont know that they would be a total game changer for the germans.

I do think they would have helped, but I remain unconvinced they would completely turn the battle around. Westermann sort of agrees with that


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## pattle (Sep 11, 2013)

parsifal said:


> .
> 
> 
> I need convincing, and so does Professor Westermann who wrote the defeinitive English language version on the German flak arm. There were numerous other problems facing the German flak arm, VT fuses would have helped, but I dont know that they would be a total game changer for the germans.
> ...



Well both you and Prof Westermann are perhaps taking this a bit to seriously if you actually need convincing, the war ended 68 years ago so the answer is of no consequence. I am not trying to convince anyone of anything, to me this is only a hypothetical topic for discussion.


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## bob44 (Sep 11, 2013)

I believe there is more to it than just having the VT fuse. The German's were effective when the bombers where over a concentrated flak area. The Allies took great steps to avoid the flak areas. If the German flak was even more widespread, precise and/or could not be avoided, no doubt the Allies would target them directly. But would the VT fuse have stopped the bombing, I say no. At least not for long.


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## bbear (Sep 12, 2013)

I hope that now I have the security and general operational story, according to Ralph B. Baldwin "The Deadly Fuze". 

The security anxiety was possibly centred around the use of VT for anti-personnel army use and the need to preserve that effect until the right strategic moment
. Numerically the largest fraction of VT production was for army Howitzer use. 

Section T (R&D team for VT) developed jamming solutions so they could test whether the technology was vulnerable to jamming by the enemy. They tried jammers for land use and for aircraft. The aircraft version was simple but gave reasonable performance. But the early VT fuses were easily 'prematurely detonated' by a complex 'jammer' at ground level almost as soon as they left the gun muzzles. Fortunately the Automatic Volume Control feature developed to reduce the chance of a 'premature' when firing low across the waves also rendered the anti personnel VT less susceptible to this kind of jamming.

AA VT early types started in production sometime in 1942. Anti-personnel howitzer and rocket VT fuzes were approved for mass production around August/September '43. By roughly april/may 1944 the VT AA fuzes were used over allied home territory against V1s, or at sea (Pacific: mostly against low flying Japanese attack or in the Mediterranean similarly by the nature of the conflict against low/diving attacks). The book gives limited references to the effect on high flying formations as by that time these would be rare. There is an account of one engagement against Japanese 'Spotter' planes in the Pacific.

VT fuzes were only authorised for use on 'liberated' land in any theatre after October 1944. In 1943 a single 'dud' fired from a sea vessel at an enemy a/c but landing onshore in Sicily provoked a shore party operation to recover it. 

Section T used two teams to develop jammers neither of which appears to be connected to the Wright Field team. So what the USAAF were concerned about remains something of a mystery - aggressive rockets or aggressive AA or defensive jammers against our own efforts against LW bombers?

That's as far as I can go on security matters and 'overall sub plot'.


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## bbear (Sep 15, 2013)

stona said:


> Nobody convinced me that the proximity fuses would transform Luftwaffe flak into a weapon system capable of devastating allied formations. The Luftwaffe originally thought they needed to get the shell (88mm) within 30m of a bomber to destroy it. This was revised_ down to 3m_. That's the problem. Your projectile needs to pass within 3m of the target to be "devastating" and nothing here has convinced me that this was possible often enough to have a huge effect on allied losses.
> Cheers
> Steve



Not 3m for a proximity fuse. I take it that the mechanism in that case was the blast damage breaking structural member. Which makes sense for an ordinary shell (because the fragments arriving mseconds after the blasdt wave would be within the 'preblasted' region if the shell exploded at all early (3 meters before the shell reached the airframe) or wouldn't impact at all if the shell burst past the aircraft. In a VT shell the detonation distance from the plane is adjusted by trial and error research to use the fragments and the blast wave together. (Maybe the blast wave to 'pre stress' the metal panels and thus the load bearing members of a plane the fragments arriving milliseconds later taking the combined stress past failure - either blowing away large areas of skin or doing worse damage. At least that's the way I imagine it. )

The distance of detonation may have been 20ft. In any case the area of 'lethal' destruction at minimum with the smallest 3.5" shell was very roughly equivalent to about 25ft radius with the best type 53 fuse and a 5"3/8 shell about 46ft radius, estimated using test ammo against a test plane suspended from pylons - mostly a 'Kate'. 

(A VT fuze can give you a detonation disatnce correct to about 2or3 ft as far as I can tell/guess - or be a dud/premature completely)

Just running through the advantages of VT as I understand them: 
No fuze setting - increases rate of fire (for the British vs V1s about double) x2 advantage to VT

Crew or autoloader can load VT, then wait and fire (there is no 'race' to predict aim and fire gun before the fuse setting becomes obsolete) shots taken are always at the highest accuracy possible. guess - another x2 advantage?

Depth (time accuracy factor) eliminated : to get a detonation within 3 meters either side at 1200ft per second typical approach speed with a fuze capable at best of 0.1second innate precision (never mind the accuracy of time of flight calculation) is a chance of 1 in 4 in the depth dimension at best. 20 - 25% accurate vs VTs 90% reliability. a x4 advantage

Bigger lethal diameter due to different mode of action about 23 feet radius minimum 46ft maximum: call it 15 m diameter from the surface conservatively : 'hit rate' advantage to VT of about x5?

If that's somewhere in the right region then a VT shell on average would be on the close order of 40 times as lethal as an ordinary shell against B17s and the like. Worth having - but not decisive on its own? (by on the close order of 40 I mean somewhere around 20 to 80). That's consistent with the reported UK result vs V1s of 2500 shots/kill to 100 with VT and still getting better.

Further advantage against low fast targets? - you get one more aimed shot in before the target closes or is obscured ?


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## stona (Sep 15, 2013)

I'm only repeating the Luftwaffe's own opinion. An 88mm shell had to explode within 3m of the bomber to ensure destruction. Whether that was a timed fuse or a proximity fuse doesn't seem to make 5x the difference to the destructive radius in anyway I can see. I'm not an explosive ordnance expert 
Cheers
Steve


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## cherry blossom (Sep 16, 2013)

There is a 1946 US report on the effectiveness of Japanese anti-aircraft artillery http://www.fischer-tropsch.org/prim...Reports/USNTMJ-200F-0370-0383 Report O-44.pdf that presents Japanese Army estimates of a “radius of rupture” to compare with the German estimate. The estimate on page 11 was a 7 metre radius for a 88 mm shell. I am not sure what any of these guesses mean because aircraft are not point targets but I suspect were sometimes treated as points to simplify the maths. It is also clear that the fragments from a moving shell will destroy targets in something more like a cone than a sphere.

Note that I am not suggesting that Japanese shells were better than German. In fact, I have heard that German shells were more effective than those of similar weight from other nations because they were cut during manufacture to generate “optimal” sized fragments. I suspect that most nations did static tests which would generate an estimated radius of effectiveness. However, it might be important to check the extent of damage that was estimated to lead to a targets destruction. From a German point of view, a British aircraft that crashed on the way home was as destroyed as one that crashed immediately. However, the anti-aircraft battery would only be credited for the one that was immediately destroyed. Also for a USN ship firing at a kamikaze, damage that would have stopped the aircraft getting home was less significant.


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## bbear (Sep 16, 2013)

To be clear i am no munitions or ballistics expert but i just want to make sure the VT gets its proper balance of advantage it won't change the outcome but it's best to have understanding.

I suspect that both german and japanese figures quoted by both of you are based on the pure explosive 'shock wave' damage. That is exactly because they are expressed as radii from detonation point (pressure shock wave doesn't move forward with speed of shell) whereas just as you say fragment damage would be expected to be a cone - the 1000 or so fragments disperse at around 2200 ft per second in whatever direction - added to the vector of the shell.

The VT developers could actually select the sensitivity of the fuze to set a distance ( i now find that for most shells and fuses they used this turned out to be 70 feet). They found an improvement in what they classified as 'lethal damage area ' of up to 25 or 50 times in area compared with the damage done by contact fuzes (thats ones that actuallly made contact). The VT performed best in 'head on' approach compared with a contact shell.

For a Type 53 fuze on a 5"38 shell in head on mode the 'lethal damage area' is 6800 sqft 

(btw figure are from 'the deadly fuze' book - sorry to keep quoting the same reference but the figure is backed up by one or two 'Bureau' and navy sites - but so much so i think that the books table is closest quote to the primary source) 

if you are still puzzled and until a ballistics expert appears you might try the high school physics i used to check this. Starting 6 or 7metres call it 20ft short of the middle of the target calculate how far any fragment travelling at 2200 ft per second radially would get before impact (2200 was a figure i got from online source so a low credibility but it 'sounds right'). Result is about 40 or 50ft right? The area goes up by the square of the distance from target. And that is a 100% swept area as far as the aircraft skin is concerned until the pattern of fragments loses cohesion. Because the fragments take some time to acceelerate to 2200 ftpsec the real radius would be much less - as far as i can tell the 'delayed fragment' diameter of effect would be about - 88 to 100mm for a 88mm shell. Thats why 70 ft distance of detonation is much better than 6 meters or 7 metres

or you may want to remember the effect of 'grape shot' (smooth bore cannon stuffed with bent nails, bits of chain, fragments) in the days of wooden ships at very close quarters. Fire when range is too close and the enemy ship gets a small entry hole big exit hole in the side, too far away and her wood work is pockced with bits of nail, but hit the distance exactly right - 6ft hole and internal space smothered in splinters) - that's the effect the sectiion T team were playing for, calculated and tested. Admiral Blandy 1925 is said to have been one of the many voices pointing this out. The problem was to make a proxdimity fuse that worked.

Up to 50 times advantage, i was going easy at claiming only a factor of 5.

That's nominal, test data, at the 'best angle, - other analysis loosely referred to in the book gives an operational total advantage of VT vs other ammunition of 3 at first going up to 6 to 1. But there was so much going on at the same time with predictors and radar ranging that such analyis must have been difficult (i'm guessing again but i have to make an explanation of why i credit one number more than the other). Of course i only have one real reference and that's written by an insider and will no doubt be subject somehow to 'agency bias' in the attribution of praise but - it still makes sense.


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## bbear (Sep 16, 2013)

And thanks cherry blossom for the effectiveness data: I'd like to use it but I can't see the connection between enclosre A where it mentions rupture radius and the fragment impact analysis in the main body - did i miss something?


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## cherry blossom (Sep 16, 2013)

I don't expect a simple relationship as the calculation of a, b and c etc. was from the IJN, who used a 12.7 cm gun, and the enclosure was from the Army who used 7.5 cm, 8.8 cm, 12.0 cm and 15.0 cm guns.

I mentioned the report on Japanese anti-aircraft shells because I knew that it existed. I suspect that there existed much better American, British and probably German data on the effectiveness of anti-aircraft shells exploding at various distances from aircraft. 

I found an example of the detail of American analysis using Google at Office of Medical History but this does not immediately answer the question of how damage changes with distance, especially as the analysis necessarily uses only aircraft that survived. However, the effect of the shell's motion is clear from the data comparing fragment strikes on the top and bottom of the wings: “The figures in columns 3 and 6 of table 237 show that the greatest density of hits occurred on the bottom surfaces of B-17 aircraft. The density of hits on vertical surfaces was only slightly less, whereas the density of hits on top surfaces was approximately one-third as great as that on bottom or vertical surfaces.”


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## bbear (Sep 17, 2013)

thnaks cherry b, that source is actually the one i got my approx 1000 fragments dispersing at( from that or another source) 2200ftpsec but with the shell speed of 1,100ftpsec from my 'deadly fuze' book.

the hit data is highly suggestive if you want it to be, but my instinct is that it's not fair to take data gathered for one purpose and use it for another. The doc's had a different problem to solve : where would we put more pilot armour on a b-17 or b 24? That's not the same as what burst disstance, if any, makes armour redundant as in -armour for pilot? pilot of what? (my alarm light labelled 'Respect - always, respect.' just lit up).

Raher than risk explaining any further - you are right I need to find a good contemporary analysis source and read it (preferably 3 sources), then a good modern ballistics book, read it and then come back to you. This will take a few months.


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## gmsw7 (May 25, 2016)

Have a look at the attached nara fms D031 by Gen W von Anthelm re use of contact fuses (as mentioned indirectly in very good flak book by E Westermann)

Mentions/describes a raid in april 1945 he witnessed where "17 of 180-200 bombers attacking airfields around munich" were shot down

I had a quick look through 8th af missions april 1945 but could not see a mission with such losses - but no expert


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## Shortround6 (May 30, 2016)

bbear said:


> if you are still puzzled and until a ballistics expert appears you might try the high school physics i used to check this. Starting 6 or 7metres call it 20ft short of the middle of the target calculate how far any fragment travelling at 2200 ft per second radially would get before impact (2200 was a figure i got from online source so a low credibility but it 'sounds right'). Result is about 40 or 50ft right? The area goes up by the square of the distance from target. And that is a 100% swept area as far as the aircraft skin is concerned until the pattern of fragments loses cohesion. Because the fragments take some time to acceelerate to 2200 ftpsec the real radius would be much less - as far as i can tell the 'delayed fragment' diameter of effect would be about - 88 to 100mm for a 88mm shell. Thats why 70 ft distance of detonation is much better than 6 meters or 7 metres



Something seems more than a bit off here. Or I am not understanding the situation. The Fragments spend about zero time/distance accelerating. They are moving about as fast as they will ever go within a few inches of the shell bursting. Fragments have really crappy ballistic shape, they make round balls look good and they slow down fairly quickly, a lot depends on size which is why so much work was put into optimizing fragmentation, matching explosive to shell body material/alloy and heat treatment. Too many small fragments and the lethal destiny of the "cloud" thins out pretty quick and lethal range is short. Too many big fragments (a sort of contradiction in terms, large size fragments means you won't have a large number of them) and the big fragments are dangerous to large distances but with few fragments the chances of a hit go down. The 2200fps figure may have been an average or average speed at a given distance. 
Most extreme example is the old cast iron Pineapple grenades which, if filled with HE never split up along those grooves. They split up into 3-5 large chunks and a lot of cast iron dust/powder and while the large chunks were dangerous at over 100yds at times the dust was pretty ineffective at just a few yds. 
Now a 70ft "miss" distance is way too far away to be effective. Please do the math. 70ft radius means a 219.8 circumference. even if you can get the large majority of fragments to stay within 10ft forward and aft of the center of the shell in a horizontal fan that is a 20ft high area and thus your fragments are going into 4396 sq ft area, At 70 ft how big does each fragment need to be in order to penetrate the aircraft skin *and *do damage behind it. Just poking holes in the skin does not bring the aircraft down. 



> or you may want to remember the effect of 'grape shot' (smooth bore cannon stuffed with bent nails, bits of chain, fragments) in the days of wooden ships at very close quarters.



Actually what you are describing was called scattershot (or other names) Grape shot was actually a cluster of identical sized balls often wrapped in canvas that resembled a bunch of grapes. While such _expedients _as _ bent nails, bits of chain, fragments _were used on occasion they were much too unpredictable to be used by professional gunners as common practice. They also could jam in the bore and burst the gun on occasion and were much rougher on the bore (greater wear) than "standard" ammunition. Brass or bronze barrels being more common than Iron. Also in an era were nails were hand forged by blacksmiths bent nails were hardly the "scrap" they are considered today. 
What gunners used for real ammunition and what non-gunners (infantrymen and cavalry men) wrote about in memoirs were often very different things. The famous quote by Zachary Taylor "A little more grape Capt. Bragg" actually went more like.
" What are you firing Captain?"
"Canister sir"
"Well double it and give them Hell"


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## JSF (Aug 5, 2016)

Website with CIOS reports:
CIOS

The very first one (pre-VE day) tangents the subject already:
CIOS-I-1
http://www.cdvandt.org/CIOS-I-1.pdf

I never saw any ALSOS-C reports.

There's a German book on German WW2 missiles, but I don't have it and cannot look up the fuzes mentioned. 
Amazon product
_View: https://www.amazon.de/Flugk%C3%B6rper-Lenkraketen-Die-deutsche-Luftfahrt/dp/B005ZYYEM6_

A revised edition is overdue since 2007, supposed to be published in 2016:
ISBN 978-3-7637-6120-3

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## pinehilljoe (Aug 6, 2016)

pattle said:


> Germany was only still developing the proximity fuse at wars end after its development had been interrupted by a Hitler order around 1941. The proximity fuse was used with great effect by the Allies, most notably against the V1 flying bombs against which it was highly successful. The Americans were very mindful of the Germans reverse engineering proximity fuses and would at first not allow their use over enemy held territory through fear of a dud being captured. Proximity fuses were later used against ground targets with devastating effect and are generally considered to be one of the major inventions to come out of World War Two.
> German anti aircraft batteries concentrated their fire into a box and relied on timed fuses which were timed to exploded at a pre-determined altitude with the hope and expectation that shell splinters would destroy the oncoming enemy aircraft. If the Germans had of had proximity fuses fitted to their anti-aircraft shells then presumably this would have made them far more effective as the fuse itself would have exploded the shell upon detecting the presence of a bomber.
> Obviously the Allies had seen for themselves just how effective proximity fused shells were against the fast moving flying bombs and they would have been more than a bit concerned about the safety of their slow moving four engine bombers should the Germans had developed their own.



The fuse was developed at the Applied Physics Lab, the team was led by William Parsons. It was quite a breakthrough. The fuse was even more devastating against land targets, allowing air bursts. It was so effective, the US vacillated in using the fuse, for fear the Germans would obtain one and copy. Parson went on to be the person in the Enola Gay to arm the Bomb


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## CK JAGUAR (Apr 16, 2017)

Reading this forum is very entertaining. So many experts, each one proving the impossibility of ever building a proximity fuse. They must all have gone to public schools and attended college recently. The snowflake generation and it's knowledge level impresses me less every day.
Oh, I almost forgot, try reading Tuxedo Park. It's an actual book and it explains in some detail the work of Alfred Lee, Loomis. Or, if you're a snowflake, watch this video. It's on the web so it must be true. Now we can move on to other ridiculous opinions they learned in school.

_View: https://www.youtube.com/watch?v=Kq_Uy5hGazc_


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## tomo pauk (Apr 16, 2017)

CK JAGUAR said:


> Reading this forum is very entertaining. So many experts, each one proving the impossibility of ever building a proximity fuse. They must all have gone to public schools and attended college recently. The snowflake generation and it's knowledge level impresses me less every day.
> Oh, I almost forgot, try reading Tuxedo Park. It's an actual book and it explains in some detail the work of Alfred Lee, Loomis. Or, if you're a snowflake, watch this video. It's on the web so it must be true. Now we can move on to other ridiculous opinions they learned in school.



Re-reading the thread, my impression is that only one member said that proximity fuse is impossible to build (on ww2 technology). The member that is rather far away from the 'snowflake generation'.

Granted, a 1st post can be written without saracastic remarks about the forum's members, wheter those being experts or not.


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## pbehn (Apr 16, 2017)

Proximity fuses were used in WW2 weren't they? I have read they were used against the V1 so the technology was available at the time.

from Wiki


Vannevar Bush, head of the U.S. Office of Scientific Research and Development (OSRD) during the war, credited the proximity fuze with three significant effects.[23]


It was important in defense from Japanese Kamikaze attacks in the Pacific. Bush estimated a sevenfold increase in the effectiveness of 5-inch antiaircraft artillery with this innovation.[24]
It was an important part of the radar-controlled antiaircraft batteries that finally neutralized the German V-1 attacks on England.[24]
It was used in Europe starting in the Battle of the Bulge where it was very effective in artillery shells fired against German infantry formations, and changed the tactics of land warfare.
At first the fuzes were only used in situations where they could not be captured by the Germans. They were used in land-based artillery in the South Pacific in 1944. Also in 1944, fuzes were allocated to the British Army's Anti-Aircraft Command, that was engaged in defending Britain against the V-1 flying bomb. As most of the British heavy anti-aircraft guns were deployed in a long, thin coastal strip, dud shells fell into the sea, safely out of reach of capture. Over the course of the German V-1 campaign, the proportion of flying bombs flying through the coastal gun belt that were destroyed rose from 17% to 74%, reaching 82% during one day. A minor problem encountered by the British was that the fuses were sensitive enough to detonate the shell if it passed too close to a seagull and a number of seagull "kills" were recorded.[25]

The Pentagon refused to allow the Allied field artillery use of the fuzes in 1944, although the United States Navy fired proximity-fuzed anti-aircraft shells during the July 1943 invasion of Sicily.[26] After General Dwight D. Eisenhower demanded he be allowed to use the fuzes, 200,000 shells with VT fuzes or (code named "POZIT"[27]) were used in the Battle of the Bulge in December 1944. They made the Allied heavy artillery far more devastating, as all the shells now exploded just before hitting the ground.[28] It decimated German divisions caught in the open. The Germans felt safe from timed fire because they thought that the bad weather would prevent accurate observation. The effectiveness of the new VT fused shells exploding in mid-air, on exposed personnel, caused a minor mutiny when German soldiers started refusing orders to move out of their bunkers during an artillery attack. U.S. General George S. Patton said that the introduction of the proximity fuze required a full revision of the tactics of land warfare.[29]

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## pbehn (Apr 16, 2017)

From reading this
Proximity fuze - Wikipedia

The Germans did not have the technology to develop/produce proximity fuses during WW2 but that does not mean in a different scenario it could not have happened, after all the Russians stole the technology, from the same article.....

While working for a defense contractor in the mid-1940s, Soviet spy Julius Rosenberg stole a working model of an American proximity fuze and delivered it to the Soviet intelligence.[13]

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## Shortround6 (Apr 16, 2017)

The big problem wasn't the basic idea or even building a prototype. The *BIG *problem was being able to mass produce the things. 

According to one story "By the end of the war, five separate manufacturers and 80 subcontractors around the country were producing 40,000 fuses day -- using the labor of 80,000 people." 

For a good overview see; http://webarchive.loc.gov/all/20140704031301/http://www.history.navy.mil/faqs/faq96-1.htm

Please note that even making batteries for the smaller fuses that had decent shelf life was a problem, let alone the tubes/circuits, and other parts.

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## swampyankee (Apr 16, 2017)

SF author George O Smith was involved in the development; Arthur Clarke, who was involved in the development of ILS said he thought the VT fuze was one of the toughest technology projects of the war. It was tough building the Copperhead missile with solid state electronics. Imagine building something, like the proximity fuze, to be fired out of a cannon with _tubes.
_

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## delcyros (Apr 17, 2017)

Cover name of german proximity fuzes furing ww2

BAD, akustic developed by Graf Zeppelin Institut

ELKU (a.k.a. "PABLITZ") electro-acustic, developed between TELEFUNKEN and PABLITZ & Elektro-akustisches Institut, Namslau

FUCHS, active radar, developed by AEG Berlin, scheduled for Hs-117 and Hs-298

MARABU, replaced FUCHS, aktiv Doppler by Siemens-Halske subcontracted from Rheinmetall AG.
Developed for Hs-117, Hs-298, Rheintochter und Wasserfall SAN. Pre-series production finnished

MARDER and ISEGRIMM, electro-magnetic, developed for mine warefare by Orlich Institut, Danzig.

KAKADU, active radar by Doppler effect developed by Donauländische GmbH, Wien. Produced in order of 3,000 specimen for Hs-293

KRANICH, acustic by Ruhrstahl AG, Brackwerde. taken from developmental list late in 1944

KUGELBLITZ, aactive radar, Doppler by Patent Verwertungs Gesellschaft, Salzburg.
developed for SAM Rheintochter. Small series production

KUHGLOCKE, passiv electrostatic ("Glimmröhrenzündung") by Rhinemetall-Borsig. Only Prototypes

KUHGLÖCKCHEN, micro KUHGLOCKE for FLAK 88-128mm SPgr, series production scheduled for march 1945

MEISE, acustic by Neumann & Borm, Berlin, taken from developmental list nov. 1944.

PINSCHER, aktiv radar Doppler by Orlich Institut, Danzig. 5 Prototypes.

PISTOLE, photo-elektric, by AEG 

ROULETTE, infrared by Brickmann, Gera.

STIMMGABEL, Akustic by Graf Zeppelin Institut. Developed for parachute delayed bombs to be dropped over bomber combat boxes. Testet, development cancelled.

TRICHTER, radio doppler by Blaupunkt. In series production by feb. 1945, in april 1945 in combat trials.

WASSERMAUS, photo-elektric, for C2W10 Wasserfall SAM.

WIESEL, aktive radar doppler by Orlich Institute, Danzig.

ZÜNDER-19, developed for SC-250kg GP bonbs by Rheinmetall-Borsig. started 1937, finnished 1943. Produktion to mid 1944

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## swampyankee (Apr 17, 2017)

I think a lot of people forget that the Germans weren't the only people in the WW2 era that had brains. While they did have some "firsts," among other things, they were not able to produce a reliable wood glue for aircraft, centimetric radar, or a proximity fuze.


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## Shortround6 (Apr 17, 2017)

I have no doubt that the list provided by Delcyros is accurate as far as it goes, which is a list or programs/projects. Turning a project into _reliable _mass produced equipment was a major problem for most countries/air forces. The US for example had something over a dozen _projects _to turn the the .50 cal Browning into a 1200rpm gun ( multiple projects at multiple companies) and took something like 3 years to get any into the field. 
It was not a question of getting an idea for a proximity fuse to _work in the lab _ or even test range. It was getting it to work well over 50% of the time _in service _after the shell/fuse sat in storage for weeks or months in both tropical and arctic conditions. It was getting such a fuse to be producible in quantity (thousands per day) by production workers, not 30 or so day by laboratory technicians. Granted the Allies had longer shipping distances and transit times from factory to guns but dead batteries, broken tubes and even broken connections means a dud shell (or one that explodes using the self destruct mechanism). 
Using a proximity fuse on a missile is several orders of magnitude easier than using one on an artillery shell. The volume constraints go away (for the most part) while the firing stresses are much reduced, much lower "G" loading on launch/firing. The much lower rate of spin has advantages and disadvantages. AN 88mm gun could fire a shell with over 18,000rpm at the muzzle. 

Now perhaps the Germans did get one or more fuse designs to this level of development (ready for large scale production with acceptable shelf life and good (nobody had perfect) reliability in March of 1945. It was too late. A few dozen or even a hundred more bombers shot down in April of 1945 was not going to delay the end of the war by one day.

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## delcyros (Apr 18, 2017)

I do not disagree. What I do object, however, are the generalisations found in wikipedia that Germany did not had the technology to develop or produce proximity fuzes. After all, they developed, produced and fieldes proximity fuzed warheads in naval torpedoes and mines, as well as in bombs early in ww2. They also developed proximity fuzes in AAA shells and SAM, though to the best of my knowledge only obtained limited production still gearing up from prototype production to series production at wars end (depending on which project You look for). To the best of my knowledge, they did not field any of them, except for R&D and demonstration purposes. 
With MT fuzed AAA shell the problem was that You needed to be precise to obtain a hit: in elevation, direction AND time. Not much of a problem for AAA trying to hit something at, say 4000ft but against a bomber operating at 20,000ft You are entering the remote upper ballistic trajectory curve, and pointing errors became more common with the common 88mm Flak 18/36 as it slowly approached it´s effective limit. US Surveys of Flak damage during ww2 indicated that FLAK litterally was precise. Hundreds of bombers came back where an 88mm went right through the A/C or the wings to explode outside harmlessly a distance beyond the plane. This didn´t went unnoticed in Germany, as there was a consistent upgrade environment for AAA shells.
The stop gap wasn´t yet the developmental proximity fuze, rather, it was the reliability of operation provided by installing a double fuze: MT & impact (non-delay action). This was first suggested in early 1944 with approx. 2 mio. shells manufactured 1943 & 1944 but fielding of them was initially countermandated on account of the higher danger during transportation. Only during april 1945 did the FLAK batteries around Munich received clearence to field test their stock of double fuzed AAA shells with the result that the number of bombers brought down increased fourfold for the same amount of ammunition spent.


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## Shortround6 (Apr 18, 2017)

The ability to make proximity fuses for torpedoes/mines is hardly an indicator of the ability to make proximity fuses for AA shells.

US Mark 6 exploder





space in torpedo




This was the infamous magnetic exploder. A form of proximity fuse. Other torpedoes and mines used different exploders using different principles but the size constraints were nowhere near as bad as an AA fuse. Described as fitting 300 components in a tube the size of two toilet paper tubes placed end to end. The under water exploders could also function much slower (speed of torpedo/mine being much slower than a AA shell) and the under water units also had nowhere near the "G" loads placed on them as the AA shell units did.

The basic "idea" of a proximity fuse is rather simple. Turning it into a laboratory functioning example is harder but doable using a number of different sensor systems. Being able to get it work in the field as a round of ammunition (take from box and shoot it vs take from box, test/trouble shoot/repair/retest and then shoot) at acceptable levels of reliability is another story. According to the following account the price of a proximity fuse fell from $742 to $18 by the end of the war.

See: Innovation During WWII

for some more information on the development of the Allied proximity fuse.

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## pbehn (Apr 18, 2017)

delcyros said:


> I do not disagree. What I do object, however, are the generalisations found in wikipedia that Germany did not had the technology to develop or produce proximity fuzes.


I was not meaning to be derogatory just stating a fact. German technology was good but to affect the war air defense needed huge numbers of fuzed munitions in late 1943. Ammunition that explodes in transit or being handled is not a minor issue, it is solving these issues that takes the time. The allied (American) use against the V1, the Battle of the bulge and against kamikazi were very limited compared to the task of defending the whole of Europe from high altitude air attack.

There is no doubt Germany could have developed working proximity fuses and mass produced them but not in time to affect the war.


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## delcyros (Apr 18, 2017)

As above, while that is reaonable as a concept, we must be aware that the idea relies heavily on two presumptions:

A) _on the historic allied choice not to use proxy fuzes over land until "the end was in view" _(When they did finally, dud fuzes were recovered and studied)
B) _on the case the proxy fuzes were below/above the german perception realm of their needs_

As it turned out factually, there was no workable proxy AAA shell in service in Germany at wars end, so it can be deduced that both presumptions are largely, if not completely valid. However, to state that the development and production of such a design was beyond Telefunken, GEMA, Lorenz et al. capability will cause induction of a third premise:

C) _even if they had recovered a sample in time, they would not have been able to reverse engeneer it due to failing in their technology._

I stand firm that this presumption is not a valid one, the allied perception appears to be directly counterfactual to such a presumption, fear of losing VT fuze technology to be reverse engeneered beeing the main factor driving a ban against the use of VT over land.

Moving away from the proxy fuze, the question remains what effect would dual fuzed AAA shells (MT and impact fuze) have in the bombing campaign, a design which indeed was produced en masse back in 1943 and was only hold back due to a personal change in the head of the FLAK organisation and a misconception on the successor´s behalf.

statistical average of AAA ammo spent per A/C kill 1945 (figures given as ca. against daylight box formation heavy bombers in high altitude):

88mm Flak 18/36: 16000 with MT fuze, 5000 with double fuze
88mm Flak 41: 8500 with MT fuze, 3000 with double fuze
105mm FLAK: 6000 with MT fuze, 2000 with double fuze
128mm FLAK: 3000 with MT fuze, ca. 50% MT with double fuze but sample size too small to be reliable

compare Gen. of the FLAK Axthelms´s post ww2 interrogation report, the numbers he cites are different to those above but yield the same figure of merit: ca. 1:3 in favour of the double fuze.

http://downloads.sturmpanzer.com/FMS/NARA_FMS_D031.pdf

best regards,
delc

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## pbehn (Apr 18, 2017)

All true, but figures from 1945 ignore the certain fact that the allies could have stopped all bombing in January 1945 and it would have had almost no effect on the war at all.


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## delcyros (Apr 19, 2017)

The question I extract from Axthelms account is a different one than whether or not the allies would have won ww2. There is no doubt about that. 
Rather than 1945, the question whether or not the allies could decide to stop daylight bombing during spring 1944 or winter 1943/44 is cast. I don´t think they would, at least not without serious ramifications elsewhere (german fuel situation would have improved very markedly for the remainder of 44 and 45). Realistically, the option of D.Z. fuzed AAA shells was articulated late 1943 and in spring 1944 again. The shell was produced in mass, too, so we do not need to resort to proximity fuzed AAA, which is a bit of a stretch historically. The impact, this shell would cause on tight bomber combat forces is a very significant factor to this discussion. Certainly, they would have done little against the many barrier fire batteries with poor firectontroll but regular FLAK batteries, and the now employed Grossbatteries protecting key targets with multiple firecontroll radars would have received a massive increase in fire effect day and night.

MT fuzed shells striking an A/C would have rendered the fuze unservicable, causing duds and low order detonations. D.Z. fuzed AAA shells would be able to explode always high order on predefined time or impact, depending on which circuit was closed first. Rate of fire very significantly improved with D.Z. shells (similar to AAA firing VT-fuzed shells enjoying this nice side effect).


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## Koopernic (Apr 19, 2017)

There was a functioning German gun launched shock hardened proximity fuse. I know how it worked, it was test fired successfully in 1943 with a detection range of about 2m, and this was improved to 5m and then 10m and finally 15m. I'll be able to provide a few links and drawings when I get on something more comfortable than this iPad.

It was tested again in 1944 (about 1000 8.8cm rounds with a low dud rate fired). By then development was essentially complete. Conditions were poor in Germany and the Rhinemetal-Borsig factory was over run before production could begin.

I believe it could have been in service much earlier since development had been paused in 1940 for about 2 years. It was actually a very cheap fuse to produce, cheaper than the clockwork fuse and much cheaper than the allied radio fuse. The Germans had suspended work on this fuze when they were trying to muster resources for weapons that could be produced quickly during the war with France which the feared they would loose.

Despite handing over their work to the USA the British, perhaps because of national pride, continued some development of the fuse. They succeeded in detonating by remote control a few rounds in 1942. The Description is given in Louis Brown’s Book. Radar, Technical and Military Imperatives.

The British intended to use radar to track the shell via a corner reflector. Then when the reflection of the shell merged with that of the target they planned to detonate the shell via a double radar pulse. The US fuse was further along, more flexible and the British lacked resources. Anyway, they proved they could shock harden a proximity fuse.

I’ll give a quick run down on how the US fuse was shock hardened before describing the German fuse.

It’s a provable law of mechanical stress that scaling an item 10 times smaller will make it 10 times more shock resistant. This was one of the key’s to how the US fuse was developed. For instance Vacuum tubes developed for the V2 rocket could withstand 50g which is 10 times the acceleration the V2 could produce. Had they tube been scaled down by a factor of 10 it would have operated at 500g (still short of the 10,000g needed)

The US tubes were modified to shock harden them in many ways, repeatedly tested. The basic technique was to replace cylindrical electrodes with disk shaped planer ones. Initial tests with a standard miniature vacuum tube developed for hearing aids was very promising. The tone oscillator used in tests not only often survived drops from great heights on to concrete but launches from a relatively low velocity 37mm gun.

The vacuum tubes were held in place with wooden blocks and the space filled with oil so that the tube was neutrally buoyant. Thus when fired the oil was pressurised by the acceleration it was even throughout the envelope of the tube.

The German fuze worked of the electrostatic field generated by an aircraft as it moved through the air. This is massive. When the US started developing its Strategic Defence Initiative to destroy ballistic missile they developed an electrostatic fuse to destroy MIRV. It shouldn’t be regarded as inferior. The shell also develops a field around itself and the gradient caused by an aircraft effecting the field will also be detectable. Electrostic proximity fuses are almost impossible to jam but they degrade rapidly in rain (the reason the USN Buro Ord didn’t develop them)

The German fuse worked using a type of vacuum tube called a cold cathode tube (glimmer relais in German which translates into glow lamp relay). These tubes were already being used to set time delays in German air dropped bombs and so were already shock hardened. In fact examination of the German shock hardened time delay bomb fuses was what triggered the British to re-examine the proximity fuse work they had attempted in 1932.

The tube was actually filled with 0.5 atmospheres of argon gas and had 3 electrodes.
1 Cathode on to which the negative terminal of a battery or precharged capacitor was connected.
2 An anode which was connected to the positive side.
3 a second or ‘striking anode’ which was arranged to be between the above cathode and anode. If a small positive voltage was applied to the striking anode the argon would ionise between the cathode and striking anode and then carry over to the main anode and carried a large current. This could be used blow a wire fuse that would set of a primer.

Because this kind of tube lacked a heater element it was very tough and shock resistant. It also didn’t need a battery and could work of a simple and rugged precharged capacitor.

The fuse worked a follows there was an antenna on one side of the shell, actually a small whip aerial about 4cm long, hanging of the tip of the 8.8cm shell. As the shell rotated at 18000rpm or (300 cycles/second) it would alternately come closer and then further away from the electrostatic gradient of target aircaft. This presented as a 300Hz alternating current in the shell. It was filtered and possibly rectified rectified (via copper oxide diode) and if a sudden and strong increase in field occurred the voltage would exceed the striking voltage of the striking anode and the shell would detonate. A nose contact fuse, essentially a push button electrical switch was also provided to blow up the shell.

In order for a standard 88 shell to destroy a bomber it had to detonate within 3.0 to 3.5m. Detonation at 10m would typically only produce survivable damage.

Hence when the German had the fuse working at 5m in 1943 they had enough to have a useful proximity fuse.

It’s interesting to note that toward the end of the war that the Germans had worked out that a simple nose contact fuse was more effective than a time fuse. Complex expensive fuses, powerful high grade explosives and fragmentation cases produced an expensive shell in addition there was a lot of effort put into setting the fuse that reduced the firing rate. It was better to just go for a direct hit both in terms of expense and the number of aircraft brought down.

Hence the German electrostatic fuse, which was cheap to make, would have been quite good since it was a kind of nose contact fuse with proximity plus.

The Germans also planned to use this ‘cold cathode’ technology to produce electronically programmable time delay fuzes for the canon shells. They worked much the same way as the time fuzes used in some German bombs. A capacitor was precharged to a voltage that set the time delay, this discharged via a resistor into a second capacitor. When the voltage in the second capacitor reached a certain level it would reach the striking voltage of a cold cathode tube and detonate the shell. An acceleration switch in the shell would begin the timer.

The idea was to mass produce the components, age them a little, test them and sort them into batches so that they could be assembled into fuses with consistent time characteristic. A batch of resistors with a too high a value might be combined with cold cathode tubes with low trigger voltages. An adjustable trimming device would have completed the adjustment.

Obviously the electrostatic proximity fuse and the electronically programmable time delay might be combined into a single fuse. It would require only two tubes instead of one. By contrast the allied fuse needed 6 or 7 vacuum tubes and an expensive battery.

Hence one could imagine these fuses fired at aircraft, perhaps a 1/4rd blowing up too soon but the remainder either detonating at the desired point, triggering of the aircraft or achieving a direct impact or if they missed by a large margin blowing up above the aircraft.

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## Shortround6 (Apr 19, 2017)

delcyros said:


> MT fuzed shells striking an A/C would have rendered the fuze unservicable, causing duds and low order detonations. D.Z. fuzed AAA shells would be able to explode always high order on predefined time or impact, depending on which circuit was closed first. Rate of fire very significantly improved with D.Z. shells (similar to AAA firing VT-fuzed shells enjoying this nice side effect).



Actually the VT fuses that were "duds" in the air often detonated when they hit earth/water at the end of the flight if there was enough power left in the capacitor. While there was no separate contact fuse mechanism the firing circuit was controlled by a reed switch and if the shell landed in a fashion that allowed the reed switch contacts to meet the shell would detonate (again, given there was enough power left in the capacitor.)
Interestingly the Navy fuzes, and thus the vast majority of Allied VT fuzes had no self-destruct mechanism. Not a big deal if you are firing over water and away from land. Not such a good idea if used for defending a major city. British anti-diver belts of AA guns were NOT placed in areas with high populations. 

How effective the 88mm gun would have been with Allied style VT fuzes is also a question. The US 3" shell needed to explode much closer to the target than a 5" shell or more of them were needed to get the same effect. In a 5" shell the amount of explosive displaced by the larger fuse was negligible in comparison to the total amount of explosive. In the 3" shell the amount of explosive displaced was a much larger percentage of the total despite the fuze being considerable smaller (and lighter). The British 3.7" AA gun used a sort of intermediate fuze between the two and the British shell with normal fuse went 28lbs compared to the 20.7lbs of the 88mm standard shell. The Fuse for a US 5" naval gun weighed over 6lbs. For the 3" gun they got it down to 2.40 lbs. 

The 88 would be more effective than with standard fuses, just don't use the same multiplier for effectiveness that you use for the bigger shells and also note that just because you have fuse that works in 5" or 4" inch guns don't think that you have one that works in 3.5" guns.

I would also note that the Americans (I have no information about the British one way or the other) had built and tested proximity fuse jammers and after a stock of shells was captured during the Battle of the Bulge a rush order for 200 jammers was placed. I have no idea if they made it to Europe or were ever used if they did make it.


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## swampyankee (Apr 19, 2017)

One of the things being forgotten in this discussion is that in the WWII era, the U.S. probably had the best overall mix of technological and managerial methodologies for mass production, largely driven by the desire of companies to maximize overall profits, vs profit rates, i.e., make 10¢/widget for a $1 widget for 50,000,000 widgets vs $10.00/widget for a $50 widget and selling 50,000 widgets.


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## bbear (Nov 10, 2017)

Shortround6 said:


> Something seems more than a bit off here. Or I am not understanding the situation. The Fragments spend about zero time/distance accelerating. They are moving about as fast as they will ever go within a few inches of the shell bursting. Fragments have really crappy ballistic shape, they make round balls look good and they slow down fairly quickly, a lot depends on size which is why so much work was put into optimizing fragmentation, matching explosive to shell body material/alloy and heat treatment
> 
> Now a 70ft "miss" distance is way too far away to be effective. Please do the math. 70ft radius means a 219.8 circumference. even if you can get the large majority of fragments to stay within 10ft forward and aft of the center of the shell in a horizontal fan that is a 20ft high area and thus your fragments are going into 4396 sq ft area, At 70 ft how big does each fragment need to be in order to penetrate the aircraft skin *and *do damage behind it. Just poking holes in the skin does not bring the aircraft down




Shotround6 You are quite correct that I misinterpreted my text I think. Pleas understand 70ft was a distance established in experimentation. I was trying to think why that distance would be optimum. here's the key quotation in "The Deadly Fuze" Ralph B. Baldwin Presidio Press 1980 page 135
The assemblage essentially eliminated ground reflections permitting accurate measures of the fuze burst patterns . . .

Up to is point T section had been simply been guessing at the right frequency . . . . but it was clear that the fragments went sideways and forwards in a cone.

After about a hundred runs with the reduced scale fuze and plane a three dimensional model of burst locations was built up When multiplied by the fragmentation patterns of the shell one could determine.he number of fragments that would pass through the plane . . .

Luckily the shape of the shell as an antenna and the kind of electrical circuits that could be used in a VT fuze forced the fuze to trigger before it reached the target Consequently only minor adjustments were required to match fuze and fragmentation patterns to optimise burst efficiency.

. . .

Fuze sensitivity was the only variable that could be changed greatly . . . There was a broad spectrum of fuze sensitivities that yielded nearly optimum burst patterns. Almost all of the good fuzes would operate about seventy feet from the plane with a few bursting as much as far away as a hundred feet.

..


. . full scale tests corroborated the reduced scale patterns.

. . .
A team of experts examined the plane for damage after each round to assess if any specific fragment would be damaging enoough to to bring down the plane immediately or later

more to follow, sorry for the delayed response. My Parkinson's condition means I must harbor my resources before approaching a keyboard and I've been ttrough some life changes..

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## Shortround6 (Nov 10, 2017)

Thank you for your reply. I am sorry to hear of your health issues and hope things are going as well as can be expected for you. Hope this forum can be a distraction. 
No reply needed unless you are up for it. You do bring good information.

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## bbear (Nov 11, 2017)

Shortround6 said:


> Thank you for your reply. I am sorry to hear of your health issues and hope things are going as well as can be expected for you. Hope this forum can be a distraction.
> No reply needed unless you are up for it. You do bring good information.



Thanks
The same book p139 gives a table of shell efficiencies listing blast area ad lethal area using standard (D) and rdx (A) type explosives
i won'#t copy the whole table
fuze gun explosive filler burst area letal area my calculation lethal radius
sq. feet
mk32 5"/38 D 6,000 3,300 32ft 10meters
MK53 5"/38 D 18,000 5,200 40ft 12.8 m
Mk53 5"/38 A 18,000 6,800 46ft 14.8 m
Mk 47 6"/47 D 18,000 9,000 53ft 16.2 m 
That's 'lethal' as defined by expert examination as mentioned before
This data was using a Nakajima 97 'Kate' in head-on approach /aspect (the most effective)
other planes tested included a Baka, B26,B17 and B24 and more but Kate figures usually applied to the others (I guess in area)
the differences being in vulnerability (i think they mean as oppose to size). The number of VT fuzes produce in toto in thhe aris 22.1 miion of whuich 1.8% were sent for test purposes Rear Adml,. G. F . Hussey in Foreword 2. Foreword 1 is by Merle. A Tuve colmpares 'blundering effectiveness' of e vs "top down" of autocracies as being the key to German failure and Allied success at war technologies. As long as aims were kept very clear the two way criticisms of worker to supervisor to science officers to management to government and vice versa meant that the solution was quickly arrived at. Whereas a simple hierarchical obedience resulted in time wasted. He was reflecting on the findings of the technical teams sent into Germany after the war. He ends his Foreword "We learned from each othernew things about the meaning of responsible American citizenship"

You may feel as I do that a shell would be most effective at extreme range at an approaching plane or fired along the close trajectory of a diving plane. The flattening out of the trajectory towards end range would give the 'swept volume' of 140ft diameter 'tube' for each shell the maximum chance to contain the approaching aircraft. The fleet action effectiveness of VT fuzes in the Pacific were 3:1 in other words if an action would result in 1/3 enemy losses using conventional fusing with VT they would be wiped out. I don't have the page reference right nw.

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## Kaleun (Mar 17, 2018)

pbehn said:


> From reading this
> Proximity fuze - Wikipedia
> 
> The Germans did not have the technology to develop/produce proximity fuses during WW2 but that does not mean in a different scenario it could not have happened, after all the Russians stole the technology, from the same article.....
> ...





pbehn said:


> Proximity fuses were used in WW2 weren't they? I have read they were used against the V1 so the technology was available at the time.
> 
> from Wiki
> 
> ...


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## Kaleun (Mar 17, 2018)

The problem of miniaturizing vacuum-tubes (initially these were derived from hearing aid devices) was solved by the end of 1942--the "ruggedized" tube could create a radio transmitter-receiver that would detonate a 5 inch AA shell about 75 feet from a hard target (including the ground). This was developed at the Johns Hopkins Applied Physics Laboratory following organization of the OSRD in 1940. Once the signal was received, the shell would expose--shrapnel would easily dispose of a Kamikaze or Japanese fighter, the most important pressing need early in the U.S. contribution to the war. On January 15, 1943, the VT (Variable Time) Proximity Fuze was first successfully used in the Pacific Theatre, fired from the U.S.S. Helena. Watch a History Channel documentary and you will see interviews with Japanese pilots describing their comrades' planes dropping from the sky without a direct hit. It wasn't necessary.

Production VTs could withstand 48,000 muzzle r.p.m. and multiple G-forces. James van Allen (of the van Allen belts) was overall director of the project. He was commissioned Lt. (j.g.) and sent to the Pacific to "sell" the fuze. Patton called it the "funny fuze.." Forrestal credited it with winning the war (top 3 developments).

The fuze crossed the English Channel, after being adapted for artillery use. SHAEF orders were that it not be used unless absolutely necessary, which came after December 15 with the Battle of the Bulge. As an anti-personnel shell, it caused German soldiers to seek hard shelter, as shrapnel easily penetrated helmets. Bounce-back signal for detonation was enough to send soldiers scurrying for shelter. Prior to December, the U.S. was most concerned that the Germans would find a live shell and reverse-engineer it. I know of no evidence this was used on V-1 or V-2s for defense.

By the time of Vietnam, VT shells were routine. A contact exploder was a special request item. However, despite tantalizing general-press articles, the VT was not fully declassified until 1976. The first authoritative book on development and testing was by R. Baldwin, "The Deadly Fuze, " 1980. Baldwin Published a 2nd book, "They never knew what hit them," 1999, Naples, FL, with more first-hand accounts (e.g. from Germans in the Battle of the Bulge).
I personally have 2 such warheads, an "award shell," and an inert 1944 shell. Baldwin and Dr. R. H. Herman were the liasons to the Navy and Army as the shell was developed.

A related problem was the Mark 14 torpedo, available in masses in 1941. However, many such torpedoes were ineffective, turning around to strike the firing submarine. These were contact/magnetic detonated torpedoes. Magnetic detonation was unreliable and ordered by CNO to be turned off by the end of 1942.
A reliable contact/magnetic firing torpedo was a major project (Einstein was a contractor on this), with a reliable Mark 10 Torpedo Exploder Mechanism appearing in early 1945, dropped from TBM bombers in the Pacific. Innovative uses of magnetic detection and destruction (Magnetic Anomaly Detection) from bombs dropped on submarines from seaplanes were effective by mid-war.

The Proximity Fuze was a great a achievement. When 3 of 4 dummy airplanes were destroyed in final testing, the 4th test target was saved. 75% accuracy was well above what was sought, and the fuze went into production immediately. "Need to know" was an important factor in assembly--many manufacturers not involved in final assembly had no idea what they were making.


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## Barrett (Mar 17, 2018)

Fascinating discussion with much skookum info. 

So happens I'm reading Westermann's encyclopedic Flak study--not being a big arty guy, I've seen nothing remotely comparable. Checked the index but find no references for fuzes.

Been awhile since I looked at ETO/MTO bomber losses (not since the 15AF history) but I think generally Flak accounted for about 1/3 of heavy bomber losses, though that may have been known losses to enemy action, exempting operational/weather related.

FWIW:

One of my antiquer buds in California was a really bright guy who attended Cal Poly (IIRC) during the war. He and a handful of other gifted students were put to work on very specific research projects, and they were Prohibited from talking to each other about their work, on penalty of Death Or Worse. That message was reinforced periodically by taciturn men in suits with no apparent sense of humor.

Well...you know what happened. The guys did talk, and they G2'd that it was The Deadly Fuze. But they were really (really) quiet about it and escaped Consequences.

I'm mostly a PTO kinda guy and somewhere have a couple of studies showing the effectiveness of USN AA weapons. IIRC one of them noted that the VT gadget was accepted for distribution when the failure rate fell below 50%.


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## bbear (Mar 18, 2018)

Kaleun said:


> The problem of miniaturizing vacuum-tubes (initially these were derived from hearing aid devices) was solved by the end of 1942--the "ruggedized" tube could create a radio transmitter-receiver that would detonate a 5 inch AA shell about 75 feet from a hard target (including the ground). This was developed at the Johns Hopkins Applied Physics Laboratory following organization of the OSRD in 1940. Once the signal was received, the shell would expose--shrapnel would easily dispose of a Kamikaze or Japanese fighter, the most important pressing need early in the U.S. contribution to the war. On January 15, 1943, the VT (Variable Time) Proximity Fuze was first successfully used in the Pacific Theatre, fired from the U.S.S. Helena. Watch a History Channel documentary and you will see interviews with Japanese pilots describing their comrades' planes dropping from the sky without a direct hit. It wasn't necessary.
> 
> Production VTs could withstand 48,000 muzzle r.p.m. and multiple G-forces. James van Allen (of the van Allen belts) was overall director of the project. He was commissioned Lt. (j.g.) and sent to the Pacific to "sell" the fuze. Patton called it the "funny fuze.." Forrestal credited it with winning the war (top 3 developments).
> 
> ...



Thanks for that and good new information. Chapters 27 and 28 of The Deadly Fuze cover defence against V-1s of UK and the port of Antwerp respectively. For Antwerp batteries VT was made available in mid December 1944 and was in use after 1 weeks practice against tethered balloons wire covered (meaning 'chicken wire'?). The attack lasted 154 days starting 24th October 1944 ending by my calculation on 27th March 1945, about 4900 V1s used (10mn tons it says). Of these 4900 V1 2400 would have hit in the area of Antwerp port (not defined) but 2200 were shot down. Battery fire was 40% effective without VT. Eventually better than 90% of targets engaged were destroyed (Category A - exploded in air or Cat B winged exploded on ground contact). Overall defence including aircraft 91.2% 2183/2394 V1s that would have hit. typical engagement 60 seconds. Which by deduction it says means just about every v1 engaged by VT artillery was destroyed. Allied casualties 32 killed. Civilians not included I suspect.

Compare that with V1 over the channel 80 days 12th June to end of August. VT shells for the 3.7" guns arrived April 1944 and first became available shortly after the attack began. The 'roll out' of VT was such that by the beginning of August practically all the 500 guns had VT capability (including 5 btns of American 90mms) For the last 4 weeks of the 80-day attack the effectiveness was 24, 46, 67 and 79% of targets engaged were destroyed. Overall in the early weeks defences destroyed 40% and over the whole period of 100 V1s 46 were destroyed by defence forces, 25 inaccurate (sea or France), 29 got to London region. 9,300 launched in all. Casualties 5,500 dead (compared with 1st 4 months of the blitz 13,000 plus dead). 

All the above is what the book says, summarised. I have mad no attempt to verify any of it.

My comment. Many innovations and improvisations, command decisions and re-deployments were made on both sides of the channel. Germans camouflaged their sites and launched in poor visibility by preference. Major replanning of batteries to the coast plus indicators. At Antwerp the technologies and employment seeem to have reached full potential. Comparing the two attacks, possibly VT technology by itself might improve top equipment and crew by about 60% from 40% to nearly 100% of targets engaged. A game changer. But that's just one source.

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## swampyankee (Mar 18, 2018)

B
 Barrett


"Skookum?"

What does that mean?

------------------------

In answer to the OP:

One would hope not.


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## Milosh (Mar 18, 2018)

*Skookum* is a Chinook Jargon word that has historical use in the Pacific Northwest. It has a range of meanings, commonly associated with an English translation of "strong" or "monstrous". The word can mean "strong",[1] "greatest", "powerful", "ultimate", or "brave". Something can be _skookum_, meaning "strong" or "monstrously significant". When used in reference to another person, _e.g._, "he's skookum", it conveys connotations of reliability or a monstrous nature, as well as strength, size or hard-working.

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## Kaleun (Mar 18, 2018)

OldSkeptic said:


> Not as well basically as against other planes. Short range signal and needs a return signal. If it got close too the engines then fine. Plus it was fast.
> Then again the V1 was as fast or faster, and it worked real well against them. Though it was all metal of course.
> 
> But against a Lanc, or a B-17 or a B-24 .. ugly.
> ...


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## Kaleun (Mar 18, 2018)

_My father was one of the team developing the Proximity Fuze, and I interviewed Ralph B. Baldwin in 2009. I also know Dr. Robert Herman very well. WGVU produced a documentary on the Fuze which is also very good--obtainable from that station. Electrostatics pose all kinds of problems--lightning ignition, etc., would not be effective as a Time on Target (above ground) detonator. I have studied the German and Japanese records and neither had a functioning Prox. Fuze before the war ended. VT (Variable Time) and Proximity are essentially used synonymously in the military. Time delay fuzes have never been very effective. As the Proximity Fuze was 75% effective in its final trial (against 4 drone aircraft), it passed the Navy's requirement of 50% effectiveness. I'm not sure how you can say that a development that is generally regarded as one of the top 3 things that won WW2 isn't interesting or exciting, but try reading "The Deadly Fuze." Imagine being recruited for a Classified project on the sidewalk after being invited from Wisconsin to D.C. for an "interview." That's how Dr. Baldwin, an Astronomer, was recruited. They (OSRD) simply wanted the best minds possible, as the U.S. knew it was technologically far behind Germany in 1940. Gearing up for the war was authorized in August 1940 although the U.S. was "neutral" until shortly after 12/7/41._

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## Barrett (Mar 19, 2018)

Milosh said:


> *Skookum* is a Chinook Jargon word that has historical use in the Pacific Northwest. It has a range of meanings, commonly associated with an English translation of "strong" or "monstrous". The word can mean "strong",[1] "greatest", "powerful", "ultimate", or "brave". Something can be _skookum_, meaning "strong" or "monstrously significant". When used in reference to another person, _e.g._, "he's skookum", it conveys connotations of reliability or a monstrous nature, as well as strength, size or hard-working.



What Milosh said. Though I'm from the dryland part of the Great Northwest, "Skookum" was occasionally used as a compliment: astute/worthy/etc.


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## Kaleun (Mar 19, 2018)

pbehn said:


> Proximity fuses were used in WW2 weren't they? I have read they were used against the V1 so the technology was available at the time.
> 
> from Wiki
> 
> ...

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## Kaleun (Mar 19, 2018)

If you are familiar with how Dr. Merle Tuve worked as an administrator, the Proximity Fuze, developed by Section T, NDRC, OSRD, teams were shuffled around depending on the task at hand--one could find oneself the "head" of one work group and a "worker bee" in another group, at the same time. Most of the posts made since I contributed to the Forum add correct information, with more detail (.e.g. what the British did with the "POZIT" fuze, their version of the VT acquired in 1944. I gave 2 references, but by Ralph B. Baldwin which are quite comprehensive. He published "The Deadly Fuze" 4 years after full declassification. After the ware there were several published "teasers" that we had something unique, basically what it did, but no technical data. I spent a week in the National Archives at College Park gathering material based on my father's classified work during the war, which included development of the Mark 14 Torpedo Exploder and also demagnetizing equipment for surface vessels and submarines. During the war, every Navy vessel was run through a demagnetization range, which were spread world-wide, at least every 6 months (this was a requirement, whether it happened for every vessel, would require examination of all ship's logbooks). My work on those subjects was published in The Submarine Review (2009-2011).

Regarding the technical information about taking down a plane from 75 feet, my recollection is that when the fuze was detonated, shrapnel was directed at the source of the return signal. Like a shaped charge, this was more destructive. Anti-personnel artillery fuzes exploded directing the charge toward the ground, accounting for the great fear German troops had of being out in the open. I've confirmed this myself with veterans of the Ardennesoffensive (Battle of the Bulge).
I do not think the fuze was very effective against V1 and V2 rockets. Otherwise, why would OKW and AH risk so much to try to take Antwerp, which put much of Britain back within range of late-1944 rocketry of Wernher von Braun? If anyone has published, verified data on this (rather than recollections of downed seagulls), please give the reference here.

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## swampyankee (Mar 19, 2018)

Kaleun said:


> If you are familiar with how Dr. Merle Tuve worked as an administrator, the Proximity Fuze, developed by Section T, NDRC, OSRD, teams were shuffled around depending on the task at hand--one could find oneself the "head" of one work group and a "worker bee" in another group, at the same time. Most of the posts made since I contributed to the Forum add correct information, with more detail (.e.g. what the British did with the "POZIT" fuze, their version of the VT acquired in 1944. I gave 2 references, but by Ralph B. Baldwin which are quite comprehensive. He published "The Deadly Fuze" 4 years after full declassification. After the ware there were several published "teasers" that we had something unique, basically what it did, but no technical data. I spent a week in the National Archives at College Park gathering material based on my father's classified work during the war, which included development of the Mark 14 Torpedo Exploder and also demagnetizing equipment for surface vessels and submarines. During the war, every Navy vessel was run through a demagnetization range, which were spread world-wide, at least every 6 months (this was a requirement, whether it happened for every vessel, would require examination of all ship's logbooks). My work on those subjects was published in The Submarine Review (2009-2011).
> 
> Regarding the technical information about taking down a plane from 75 feet, my recollection is that when the fuze was detonated, shrapnel was directed at the source of the return signal. Like a shaped charge, this was more destructive. Anti-personnel artillery fuzes exploded directing the charge toward the ground, accounting for the great fear German troops had of being out in the open. I've confirmed this myself with veterans of the Ardennesoffensive (Battle of the Bulge).
> I do not think the fuze was very effective against V1 and V2 rockets. Otherwise, why would OKW and AH risk so much to try to take Antwerp, which put much of Britain back within range of late-1944 rocketry of Wernher von Braun? If anyone has published, verified data on this (rather than recollections of downed seagulls), please give the reference here.




Against the V-2, proximity fuzes were probably useless, as these were essentially primitive tactical ballistic missiles, and the fire control systems and fuze systems of the era weren’t capable of intercepting V-2. The V-1, on the other hand, flew fairly slowly and straight and level; it was an easier target than a manned aircraft not on a collision course. 

Antwerp was a major port. Letting the Allies have it would make the supply situation for the Allies much easier.

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## bbear (Mar 19, 2018)

Kaleun, Sir
Regarding the technical information about taking down a plane from 75 feet, my recollection is that when the fuze was detonated, shrapnel was directed at the source of the return signal. 
My best bellief is that basic ballistics makes a cone of debris forward in the line of flight. Downwards for a howiter shell.

Like a shaped charge, this was more destructive. 
(what analogy is there? morre destrucive than blasst damage at 75ft? or more than a shrapneel cone pointing uupwards as it might be with a time fuze?)

Anti-personnel artillery fuzes exploded directing the charge toward the ground, accounting for the great fear German troops had of being out in the open. I've confirmed this myself with veterans of the Ardennesoffensive (Battle of the Bulge).
(there was no separate anti-personnel VT fuze, VT took out any soft targett inclluding entreched troops)

I do not think the fuze was very effective against V1 and V2 rockets. 
(V1s aren't rockets van braun had nothing t do with their design AFAK. The fgures I gavee above seem to indicate otherwise)

Otherwise, why would OKW and AH risk so much to try to take Antwerp,
( it was the only deepwater port except Mulberry 1 UK AFAIK, Do you mean the Scheld/Walcharen Island? If you mean the bulge surelly that was an attempted encirclement)

which put much of Britain back within range of late-1944 rocketry of Wernher von Braun?
(V2 were launched AT Antwerp,not from it. )

If anyone has published, verified data on this (rather than recollections of downed seagulls), please give the reference here
(my dad was at Antwerp 1st Mountain Rgt RA. good enough?* apart from the Deadly Fuze, of course.)

*edit (by which I mean I have taken some trouble to read about Antwerp and the Battle for the Scheldt to a degree and I'm pretty confident, though I will check)


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## bbear (Mar 20, 2018)

Subsidiary question. If the German Proximity Fuze had been fitted to V2 rockets and V1s thus giving guaranteed 'airburst', how much more destructive would they have been? Enough to justify the programs? They were terror weapons that didn't kill many people 3 deaths per V1 aimed at London at the beginning of the campaign 1944. to 1:1 at the end (the Deadly Fuze Chapter 27). And for the whole V2 campaign against London and Antwerp 1:1. (wikipedia). Airburst 2,000 lb bombs dropped by the Luftwaffe had disproportionate destructiveness. Yet no discussion AFAIK of bombs being considered for VT fuzing? The allies did later develop VT fuze Army rockets.


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## Shortround6 (Mar 20, 2018)

The VT fuse simply detonated the shell, the fragment pattern was pretty much the same as a time Fuse (not exactly because the VT fuse was larger and some of the HE had to be taken out to fit the VT fuse) and any thought about how shells flew and how they detonated would show that this is a fairy tale.
Same with effects against personnel on the ground. Getting air burst shells without the VT fuses was a combination of science and art. However it had been being done since the days of muzzle loading artillery and for the same reasons. the shell may burst in the air but the vast majority of fragments, even as they spread out, will retain some of the forward vector/velocity of the shell. Shells that hit the ground before exploding have a large portion of their fragments absorbed by the ground. 
Shrapnel shells used just enough explosive to break the shell up/eject the shrapnel. Velocity of the shrapnel "bullets" was dependent on the velocity of the shell.

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## bbear (Mar 22, 2018)

Kaleun said:


> If you are familiar with how Dr. Merle Tuve worked as an administrator, the Proximity Fuze, developed by Section T, NDRC, OSRD, teams were shuffled around depending on the task at hand--one could find oneself the "head" of one work group and a "worker bee" in another group, at the same time. Most of the posts made since I contributed to the Forum add correct information, with more detail (.e.g. what the British did with the "POZIT" fuze, their version of the VT acquired in 1944. I gave 2 references, but by Ralph B. Baldwin which are quite comprehensive. He published "The Deadly Fuze" 4 years after full declassification. After the ware there were several published "teasers" that we had something unique, basically what it did, but no technical data. I spent a week in the National Archives at College Park gathering material based on my father's classified work during the war, which included development of the Mark 14 Torpedo Exploder and also demagnetizing equipment for surface vessels and submarines. During the war, every Navy vessel was run through a demagnetization range, which were spread world-wide, at least every 6 months (this was a requirement, whether it happened for every vessel, would require examination of all ship's logbooks). My work on those subjects was published in The Submarine Review (2009-2011).
> 
> Regarding the technical information about taking down a plane from 75 feet, my recollection is that when the fuze was detonated, shrapnel was directed at the source of the return signal. Like a shaped charge, this was more destructive. Anti-personnel artillery fuzes exploded directing the charge toward the ground, accounting for the great fear German troops had of being out in the open. I've confirmed this myself with veterans of the Ardennesoffensive (Battle of the Bulge).
> I do not think the fuze was very effective against V1 and V2 rockets. Otherwise, why would OKW and AH risk so much to try to take Antwerp, which put much of Britain back within range of late-1944 rocketry of Wernher von Braun? If anyone has published, verified data on this (rather than recollections of downed seagulls), please give the reference here.


Kaleun, Sir. I'm not sure if it counts as publication but this video has been approved for release by APL the speaker is an author of 2 books

_View: https://www.youtube.com/watch?v=LyDlq77GVPM_

He has a lot more access, it seems, to relevant personnel and materials from the period than any I've seen. His conclusions on Naval use of VT and anti-V1 s contrast with yours I feel. His conclusion that Kamikaze attacks were a response to improved USN gunnery seems plausible. As for performance against V1s his conclusions mirror my mine, although mine are much less credible.

As to performance against B!7's it seems to me that a V1 at 2,400 feet might subtend an angle at the aiming observer about that of the total 'hit' area of B-17 box at 24,000 (10x the distance 10x the size). Taking the increase in effectiveness as 5x as in this source page 17. http://www.dtic.mil/dtic/tr/fulltext/u2/a421867.pdf And the number of rounds per kill of German AA in 1944 from parsifal in another thread as 16,000 (Prof. Westerham I believe). That would drop to !/3000 roughly.

If so that would be insufficient to make the USAAF or BG give up. But it might reduce B-17 bombing accuracy and increase losses. So some critical engagements might go the other way than historically. For example the degradation of fuel supply might be delayed leaving a better introduction for the Bulge with regard to tank fuel. Maybe?


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## J.A.W. (Apr 11, 2018)

From the curious proximity fuse application dept:

Chris Thomas in 'Typhoon & Tempest Aces of WW 2' - on P. 56 notes that during anti-V1/cruise-missile ops:

"Australian John Horne, attempted to catch one while still carrying his rockets after an uneventful anti-shipping
reconnaissance. Unable to close to effective cannon range, Horne lifted the nose of his Typhoon & launched
4 pairs of rockets at his tiny quarry. At least one of the impromptu weapons hit the 'buzz-bomb', which broke
up & spun down into a field.

This led to the rapid trial of 'Z-battery' AA rockets, complete with proximity fuses, in place of the
standard rockets. & although successful on one occasion, the device was not adopted."


So, an early example of advanced hit-probability air-to-air missile interception tech, which no doubt, the LW
would've liked to have available in mid `44, too..

Edit: Corrected typos.

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## basil (Mar 15, 2019)

I have to say that Koopernic's post #79 of this blog is the first detailed description of a German AA artillery VT fuze I have read in the literature or in the net. Until now most of the sources I have seen just rely on a vanished (?) CIOS report mentioning Kuhglöckchen as electrostatic influence fuze without technical details. Even Fritz Trenkle does not tell anything about it in his books.

Unfortunately Koopernic does not seem to be active in this forum anymore. Does anybody know more about the original source of his description?


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## bbear (Mar 16, 2019)

basil said:


> I have to say that Koopernic's post #79 of this blog is the first detailed description of a German AA artillery VT fuze I have read in the literature or in the net. Until now most of the sources I have seen just rely on a vanished (?) CIOS report mentioning Kuhglöckchen as electrostatic influence fuze without technical details. Even Fritz Trenkle does not tell anything about it in his books.
> 
> Unfortunately Koopernic does not seem to be active in this forum anymore. Does anybody know more about the original source of his description?



Hi, I found 1 reference to the fuze developed by Rheinmettal Borsig as described by Koopernic on line, it gives two sources. The piece seems to be copied to many sites.
Proximity_fuze : definition of Proximity_fuze and synonyms of Proximity_fuze (English)


*^* Truth About the Wunderwaffen by Igor Witowski
*^* CIOS report ITEM no 3 file no XXVI -1 (1945)
I have to be honest, the first source reviews in amazon give me the impression that the source is detailed but unreliable. The second is the source which if I remember correctly contains both successful and unsuccessful innovations. And the specific file is not mentioned in popular online lists.

Early posts on this thread up to 7 raise the possibility that this is a hoax and Greg P the only one of us with relevant experience can't understand how an electrostatic fuze could work.

Even given the additional details, nor can I. From altitude both shel and aircraft would have he same electrostatic charge at say 30,000 feet it's about 10kV I think, because of the ionosphere. The shell is moving that much faster, an aircraft can accumulate 1MV I'm told. So call the maximum charge difference from aircraft to shell as 1MV. Moreover the rotating wire in a field I would expect to also radiate a 300Hz wave if there were any current detected, but where would such a current come from? Rotating a wire in a static electrical field produces nothing? V field, but no H field, 'cos Static? What would induce electrons in the antenna to move (current). At any instant the whole antenna would be at the same voltage? I think all you can have is a sensitive electrometer.


Of course I could be quite wrong. Often am.


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## fliger747 (Mar 17, 2019)

The appearance of a German Proximity fuse would have of course created a dramatic emphasis on countermeasures. Jamming and fooling the Fritz X guided bomb occurred quite quickly, as did counter emphasis on the more vulnerable mother craft. Likewise the Japanese "guided" flying bomb was most vulnerable when being carried by its launching ship. 

Certainly flak batteries could be quite susceptible to suppression, fighter sweeps, VT bombs and whatnot. The component train in tech projects is also quite susceptible to disruption. Perhaps if developed earlier in the war, but later on the tide of history was like all tides.


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## Shortround6 (Mar 17, 2019)

I believe the Americans and British were working in counter measures to the proximity fuse within a few months of developing the first successful ones. Just in case the Germans or Japanese did develop something similar.


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## fliger747 (Mar 17, 2019)

Yes I saw some reference to countermeasure development. Makes sense!


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## Shortround6 (Mar 17, 2019)

it was rather easy to do, the hard part is figuring out what frequency the fuses operate on.


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## Zipper730 (Mar 18, 2019)

The question I have is: If we had proximity fuses that could take such enormous g-loads, and some were fitted to rockets -- why did we have so many guidance system failures during Vietnam?

Most were caused by the following

Dropping: Sometimes, when the missiles were put on the wings, or fuselage of the aircraft, they'd drop off and hit the ground. In cases where the missile didn't have any denting or damage to fins or shape, they would often just send the plane on it's way. I'm not sure what g-load a missile hitting the ground after dropping a few feet off an aircraft's wing or fuselage would be, but it seems quite a lot less than 5,000-8,500g on the low end to up to 20,000g on the upper end of things. I've fallen about 10-20 feet, and I figure if I had been subjected to these g-loads, I'd be mist.
Jarring: Basically, the missiles were often carried on trucks that lacked shock-absorbers. The fact that the testing facilities were not on the base, and sometimes located at separate facilities, where they would have to travel across bumpy roads, and things of that sort. To make it worse, air-bases often had these washboard structures meant to shake off FOD.
Temperature: The missiles at sea-level were in warm/hot weather, and temperatures that were -20F to -70F at around 15000 to 40000 feet where you'd typically see fighter planes operating within. The result of temperature is contraction and expansion, and different components expand/contract at different rates. As a result, sometimes missiles would pass electronic inspection, then fail spectacularly in the air.
Corrosion: The air in Vietnam was hot and moist, which can accelerate corrosion on aircraft operating with the USAF and USMC; the USN operated off carriers in the salty-air at sea. I'm not sure what the protocols for missile assembly were, but I'm curious if the missiles in either case were left partly assembled in the open.
I'm curious how these conditions would compare to conditions in territory that was controlled by the United States itself. I assume our test-facilities were on the base themselves, with air-temperature and humidity varying with location. I'm not sure how TAC & SAC varied in terms of maintenance -- SAC generally was more anal about things being done exactly right, but I'm curious if mistakes were made.


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## Shortround6 (Mar 18, 2019)

Proximity fuse was a very simple device as electronics goes. One the biggest headaches was getting a battery that worked after being in storage for up to year or more and still work like a round of ammunition. No testing or check out before firing. Ordinary dry cells (flashlight batteries ) of the time could not do this (hold a charge that long). Developing a wet battery where the acid was stored separate and would flow into the plates and start working in a fraction of second was as much of a technical achievement as the rest of the fuse. So was producing the fuse and batteries by the hundreds of thousands if not millions. 
Even a simple guided missile uses at least an order of magnitude more parts than a proximity fuse and probably several orders of magnitude and that is where the reliability went. 
Each part/component in the guidance system has to be an order of magnitude more reliable than the parts in the proximity fuse.

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## fliger747 (Mar 22, 2019)

I was curious about the tube technology used in VT fuses. Apparently they did various ruses in design by orienting the parts structurally and filling the tubes with wax! A lot of genius in design, persistence and technical capability expended here! It was done by never say impossible types!


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## Zipper730 (Mar 22, 2019)

fliger747 said:


> I was curious about the tube technology used in VT fuses. Apparently they did various ruses in design by orienting the parts structurally and filling the tubes with wax!


When you say "orienting the parts structurally" you mean putting the strongest parts in the places where the most strength is required?

I guess the wax is there because it's soft and, for most purposes (it seems) shock-absorbant?


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## ThomasP (Mar 22, 2019)

I once read that the solution for the G shock the British developed (before the Tizzard Mission) was to pot(?) the circuit in a specially developed wax-like substance. When the gun fired the pressure from the acceleration caused the substance to transition from plastic to fluid, allowing the circuit to move backwards a small distance in the projectile, while the plastic-fluid material absorbed the axial shock, and supported the tube(s?) from all directions. The article went on to say that the US and UK thought it would be better for the US to finish development of the finer/final details of the VT fuze, primarily due to a shortage of resources for production, but also for security concerns. The production capacity was an obvious problem, but the British also felt that just getting ready for production would be entail so much activity that it would be difficult to achieve without alerting the Germans. The British ran a pretty secure game during the war, but at the time they could not be sure of it.

Interesting fact, the British turned over their research on fission during the Tizzard Mission also, for the same reasons as for the VT fuze. The information included their theoretical research into fission (some of which would be useful in the development of the A-bomb) AND their design theory for a nuclear reactor for electric power production. I am sure you are all aware of the US Manhattan Project, started in 1939 (before the Tizzard Mission of 1940), but I had not been aware of the amount of info the British supplied the US, or of the research into a nuclear reactor for purposes of generating electric power. Some of the design theory for a nuclear reactor was used for the Manhattan Project, and was apparently the basis for the first post-war reactors built by the US and UK. The source of this general info was 'A Short Essay on the United Kingdom's Contribution to Nuclear Power", delivered as a hand-out in 1960 to the House of Lords and House of Commons. Apparently there was a crisis involving funding further research and development of nuclear power.

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## fliger747 (Mar 22, 2019)

The references to the structural integrity of the parts was rather vague, but indicated structural orientation to survive high G loadings along the axis of the shell and loads from the not inconsiderable rotational forces generated.


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## Shortround6 (Mar 22, 2019)

fliger747 said:


> loads from the not inconsiderable rotational forces generated.




A masterpiece of understatement. A US Navy 5in AA shell could easily hit 1000rps or 60,000RPM.

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## tyrodtom (Mar 23, 2019)

Zipper730 said:


> The question I have is: If we had proximity fuses that could take such enormous g-loads, and some were fitted to rockets -- why did we have so many guidance system failures during Vietnam?
> 
> Most were caused by the following
> 
> ...



I don't know where you got your information, but most of what you just stated is incorrect.

If a missile was dropped while loading or at any point during handling it was refused for use and sent to EOD for disposal. And dropping a missile isn't something that could go undetected. People tend to noticed when something that weighs a hundred pounds or more is dropped a few feet. It's not just the explosive hazard. There were more crushing injuries in munitions handling than any other injury.
Every missile fired from USAF aircraft ( I think) was a solid fuel missile, dropping it could crack the solid fuel. It was cast in a specific way to control the burn rate of the propellant. Additional cracks in the propellant would mean there would be much more propellant exposed for burning when the rocket motor was first ignited, in other words it could explode on ignition, or a uneven burn would make for a erratic flight path.
Some missiles and warheads were stored separate, and assembled just before use. The motors had weatherseals on the back, and that weather seal was to prevent the solid propellant from drying out, or absorbing moisture, either of which would effect it's burn rate, and a broken seal was a reason for refusal. Warheads were pretty well weather proofed themselves, plus were kept in completely weather proofed containers until assembly.
The weather in Vietnam wasn't much different from several places in the USA. You get away from the coast in several southern states, and it's about the same.
Even in the WW2 era, fuses and such were shipped and stored in very weather tight containers

As for the missile handling trucks not having shock absorbers, not true. They had springs and shocks just like any other vehicle . Plus the missile were usually hauled on trailers, and the trailers had springs,most had shocks too.
Shock absorbers are actually misnamed, they don't absorb the shock of a bump, the springs do that, the shocks just snub the reaction of the springs. Without shock absorbers springs with oscillate for several times after their compressed.

I was stationed at 7 different air bases when I was in the USAF, I don't remember any washboard surfaces meant to shake off FOD. Sometimes the roads from the munitions storage areas to the flight line may not have been the best roads on the base, but I doubt any effort was taken to make them rough.

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## fliger747 (Mar 27, 2019)

1000 rotations per second would require a twist rate in the 5"38 of one turn in about every 3' or less. I don't have the exact data for the 5' 38 but typically Naval Artillery might have a twist rate of about 1:20-25 calibers which works out to a full rotation once every 9-10' So about 1 1/2 rotations in a 16ft barrel. I come up with a WAG rotational figure of about 15,600 RPM. The "tubes" were located near the center of rotation such as to reduce the adverse effects the rotational effects. That the design actually worked is a testament to some rather good engineering!

As to whether or not the VT shells would be effective against high altitude aircraft is another question. An exploding shell at the right altitude (And a bomber formation was a somewhat stationary target altitude range wise) might be more effective than one that misses enough to not trigger the VT. Certainly the fuses were effective at closer range aircraft that might be closing range quickly, as in a direct low altitude approach.

I found a reference in 1 turn per 30 calibers... Gives me 12,400 RPM


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## Shortround6 (Mar 27, 2019)

One twist in 30 for the 5in/38 and perhaps it is calibers and not inches. 

Getting time fuses to explode at the right height was quite a trick. There are two sources of error, one is getting the correct height of the bomber/formation and a 1% error at 20,000ft is 200ft. 
2nd is the time fuse itself. Most had a tolerance of a certain percentage of the time they were set for. The time of flight to the 20,000ft area was such that many shells were exploding several hundred feet short. Germans tried an experiment of using contact fuses since the fuses seemed to have bigger error in the time of flight (point on the line where they exploded) than in getting the line of flight to intercept the target. I believe the experiment worked but it may have been in 1945 at which point it was too late. 

VT fuses also eliminated another error, most guns had the fuses "set " before the round was put in the loading tray or breech and there was a several second delay between the fuse being set and the gun fired. 
Some guns showed an increase in the rate of fire when VT fuses were used as the fuse setting step could be eliminated.


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## bbear (Mar 28, 2019)

fliger747 said:


> I was curious about the tube technology used in VT fuses. Apparently they did various ruses in design by orienting the parts structurally and filling the tubes with wax! A lot of genius in design, persistence and technical capability expended here! It was done by never say impossible types!


From memory, I can look up a passage in the book if you like, the earlier for example 45 fuzes used a perspex/plexiglass body (insulator), a tung bean oil "potting" and a can, an actual cylinder of tin, in side which the tubes were located.
The insulator allowed the antenna to operate as such.
The potting indeed dampened out shocks
The can kept the axes of the tubes in line and mechanically supported the joints of the wiring and tubes

later fuses used a
Teflon body insulator
A cerise wax 'potting'
No can

The tung bean oil (solid at room temperature) was the packing material used for the transport of valves (tubes) to from manufacturers to protect the valves (tubes) against rough handling.

Cerise wax, also solid at most ground temperatures, was better or cheaper than Tung bean oil.

The absence of a can is explained thus :
Centrifugal force can be used to separate heavy parts of a suspension from less dense parts. For example if a uniform diameter tube of human blood is laid radially to a centre of rotation and centrifuged at 10g for a minute or two the plasma accumulates towards the centre of rotation, the red blood cells towards the circumference of such a plate full of tubes (imagine the rounds of ammunition in a drum, as might be seen in a Lewis gun, points to the centre, rims to the rim as it were).

The same applies to the suspension of valves (tubes), wires, joints, suspended in the liquid wax. Believe it or not the tubes are the least dense parts of that suspension. So they all align very closely to the axis of rotation, the wax gets "spun" to the rim of the cavity. The faster the spin the greater the alignment. The fuzes were manufactured with the tubes very closely aligned, one atop the other along the axis of rotation, dependent on human dexterity. The valves (tubes) came into exact alignment because of the rotational violence done them in firing and the consequent centrifuge like effect.

This was important as one limitation of the technology was the noise at rotational frequency caused by mechanical stresses of off axis parts giving rise to electrostatic effects. That is charge distributed on one connector wire for example moving (vibrating) relative to another connection in a high impedance part of the circuit would cause a small movement of charge to and fro in that high impedance (sensing) part.

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## fliger747 (Mar 28, 2019)

Interesting information about these rather remarkable devices!


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## basil (Apr 7, 2019)

@ bbear reply #103

Thx for the links but these are the sources which are mentioned in the Internet again and again without contributing to technical details or naming original sources. 

Although GregP may be the only one here with practical fuze design knowlegde he first was not aware and / or did not believe that you could do a proximity fuze with vacuum technology although it was built hundred of thousand times and information about it is just a click away. And let´s not forget the Oslo Report of 1939 which contained parts of a German proximity fuze for atrillery shells.

I highly recommend reading Ralph B. Baldwin´s book "The Deadly Fuze" for a detailed story of the development of the proximity fuze in the US. Baldwin was part of the r&d team.

Btw it is quite certain that Rheinmetall developed an anti aircraft artillery proximity fuze based on passive electrostatic principles which was production ready at the end of WW2. It is mentioned by Fritz Trenkle (1982) in "Die deutschen Funklenkverfahren bis 1945" page 187 and in Adalbert Koch`s book (1954) "Die Geschichte der deutschen Flakartillerie 1933 - 1945" page 154. Both are very well researched books and rely on original sources.


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## bbear (Apr 7, 2019)

basil said:


> @ bbear reply #103
> 
> Thx for the links but these are the sources which are mentioned in the Internet again and again without contributing to technical details or naming original sources.
> 
> ...



Hi, good, thanks. 
I have the book by Baldwin and can confirm it's a good read. 
Regarding the certainty that Rheinmetall developed a production ready fuze I have a difficulty, two in fact.
1. If the two sources are as well referenced as you say and I confirm that they seem to be respected, why don't they have the original references for their mentions? Could I trouble you for the actual quotes from these two sources?
2. I looked at the Oslo report and this is the relevant part of the proximity fuze Wikipedia talk page

"*German work?[edit]*
The article makes a comment about abandoned German work on proximity fuzes. There's no citation, but I suspect it refers to the book by Igor Witowski which is cited in the German Wikipedia version of this article. Since that book is highly suspect, is there a reliable source for this claim and some more information? DonPMitchell (talk) 18:40, 7 April 2014 (UTC)

Looking a little further into this, there is also the Oslo Report, which described the Rheinmetall fuze, which was apparently abandoned or did not work. The tube they describe is not a radio vacuum tube, it is a type of neon lamp, used in a circuit that is sensitive to capacitive effects of nearby objects. But this was not a radar proximity fuze. DonPMitchell (talk) 18:55, 7 April 2014 (UTC)

From the report: "The newest development uses neon lamps with grids, Fig. 3. When the battery voltage is so chosen that it is just below the ignition voltage and when the grid is insulated, the lamp can be ignited by changes in the partial capacitances"One of Ian Hogg's books briefly discusses half a dozen different German proximity fuzes, using every physical principle they could think of, including radar. None seemed to work very well, or to be as simple to produce as the VT. I'll try to dig it out and give a full cite. Andy Dingley (talk) 23:02, 7 April 2014 (UTC)Sounds interesting. Neon lamps can serve as crude thyratrons. DonPMitchell (talk) 21:53, 12 June 2014 (UTC)Why not just use thyratrons? Germany was producing good thyratrons in the 1930s and exporting them to the UK. Andy Dingley (talk) 22:27, 12 June 2014 (UTC)They're pretty much the same thing. It may have been a cost or supply-shortage issue. Neon lamps were used in circuits like that very commonly. You probably also do not need the precision of a thyrotron for this application. DonPMitchell (talk) 22:26, 17 May 2015 (UTC)Actually you do - neons are far too slow. Andy Dingley (talk) 22:40, 17 May 2015 (UTC)"

I think, with respect, we must either nail down the references all the way to the origin or agree for lack of evidence to the contrary and some evidence to the fact that the Rheinmtall fuze was a sensitive electrometer that didn't work in practice and that development was stopped somewhere short of 1944. if you can see a third option I'll be more than happy to consider it.


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## ThomasP (Apr 7, 2019)

Hey guys,

I do not mean to be dismissive in any rude way - but, if the Germans had a working proximity fuse of a type suitable for use in AAA shells, and it was anywhere near ready for production by the end of the war, this information would have been available to all of us before now. And there would be no uncertainty about it.

The US and UK intelligence reports concerning this type of stuff have been declassified for a long time, and the Russian reports have largely been available since the early 2010s.

As far as I have seen there has never been any claim by any Allied intelligence unit that the Germans had or were about to have a working AAA proximity fuse ready for production. There is no benefit to be gained by anyone on the Allied side by keeping such information from the public sector.

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## basil (Apr 8, 2019)

Thx for your thoughts.

@ bbear
Unfortunately in the books of Trenkle and Koch there are no original documents or CIOS or BIOS reports mentioned where the work of Rheinmetall is described in detail. That is the reason why I would like to know where Koopernic (post #79) has got his detailed information about the function of the Rheinmetall fuze. 

However Trenkle mentions that the electrostatic fuze was designed simultaneousely at Rheinmetall and at the TH Darmstadt (by Prof. Vieweg) (TH = technical University). Trenkle, who is known for his meticulous research as a technical historian who has started his technical career in WW2 of course had a much broader possibility for research when most of the technical personnel of this period was still alive.

Koch in his book just mentions that his source relies on British and American information after the end of WW2.

In another source I have read (regrettably I do not remember where) it was stated that the AAA fuze production was planned to start during the second half of 1945 in the Rheinmetall Werks at Sömmerda - which seems plausible.

@ ThomasP
At the end of WW2 the Allies had a very satisfactorily working VT fuze in combat for over a year and the fact the the Germans were working on similar devices certainly was not sensational for the CIOS or BIOS teams. There were many other similar researches in technical fields which did not find much mention.


As the VT fuze is a product of electronic research and manufacturing capability - one may not forget that regarding electronic R&D the Allies (British and US) and Germans generally were on similar niveau during the war. 
As stated by R. V. Jones - I think it is safe to say that Germany had a lead in „the war of beams“ during the first period of war (especially in long range bomber guidance over England, but also with the introduction of the Wuerzburg air defence radar).

However, Germany missed the jump to centimeter waves in time due to several reasons although the technology was there in laboratory research scale (magnetrons, klystrons, metal-ceramic coaxial tubes). Among the reasons for not having adopted the centimeter waves until later in the war was the fact that at this time the regime forbid any research on electronics which would not be ready in the next six months (awaiting final victory) and a not very well focused strategy of common research of the major electronic manufacturers (AEG-Telefunken, Siemens; Lorenz, Blaupunkt, etc.) compared to the US. It also did not help that some scientists had for some time general reservations to the suitability of centimeter waves for radar.

During the last year of the war Germany was constantly reducing the gap in the centimeter wave field but did not quite catch up to the US and UK lead (referring to charts of Trenkle and Jones). Of course at this time the bomb raids showed its effects and slowed down all activities of research and manufacturing. Besides human resources in R&D was less than 10 % compared to the US and UK in numbers.


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## bbear (Apr 8, 2019)

basil said:


> Thx for your thoughts.
> 
> @ bbear
> Unfortunately in the books of Trenkle and Koch there are no original documents or CIOS or BIOS reports mentioned where the work of Rheinmetall is described in detail. That is the reason why I would like to know where Koopernic (post #79) has got his detailed information about the function of the Rheinmetall fuze.
> ...



I am really terribly sorry. But to me, if we don't have detail we don't have anything. To me it's an allegation about some real research with no known product. Not quite a rumour, but not far off.

I think we must agree to disagree and move on.

Thanks for the interchange though. I'm always interested in how others see things. Rationally, reasonably but not the same, like - wow!


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## ThomasP (Apr 8, 2019)

In response to basil's post#123,

I am sorry but I am not really sure what you are saying?

The Allied intelligence reports looked for and reported on any technology potentially useful in warfare that they ran across - from rifles and pistols, to tanks, to aircraft, to ships, to guided weapons,...etc. Subsequent post-war analysis of the information included everything they ran across - the quality of powder and other explosives used in munitions, the quality of armor, the quality of fuels,...the quality of electronics (both in terms of operational capability, and in terms of reliability of individual components). The information they gathered was very seldom sensational, but was pretty thorough. Some of the most thorough reports involved what technologies the Germans were working on, what progress they had made, and what the production capability was at the end of the war. Information on electronics was broken down to quality of the various tubes and circuits, by individual manufacturing companies (whether inside Germany proper or in the occupied countries), and included a company's potential capacity for volume of production of said electronics.

If the intelligence teams had run across a working, or close to working, alternative to the VT fuse they would have reported it. To have overlooked it because it was not sensational or because the Allies already had a working fuse would have been counter to their mission - and very foolish/irresponsible/criminal. Even if it turned out that the Allies decided they had no use for the technology, not reporting such a find could result in an inability to prevent the technology being used against the Allies in the future.


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## basil (Apr 9, 2019)

@ bbear 

No problem at all 
Although there are some hints from contemporary technicians - from a scientific point of view there seem to exist no black on white proof (anymore?). 

@ ThomasP

You are certainly right; there are a lot of very detailed reports. However I am not sure if really everything was covered. For example there were several projects in aircraft armarment or fire control systems which do not seem to be mentioned anywhere. Perhaps all these things are still filed in some reports or in Russian archives.


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## JAG88 (Apr 17, 2019)

IIRC Schmalenbach mentioned that the USN had no interest on Prince Eugen's radar, they simply assumed theirs was better.

The US Army thought the StG 44 was a bad weapon, didnt care for it and you know what happened.

Plenty of documents got destroyed, others ended up in the USSR and were released only in the 90s, those which survived that is.

They could have possibly been destroyed/lost, likely? Doubtful.


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## tomo pauk (Apr 17, 2019)

JAG88 said:


> ...
> The US Army thought the StG 44 was a bad weapon, didnt care for it and you know what happened.
> ...



Any chance to provide a doc or two about US Army testing and/or opinion of the StG44?


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## Shortround6 (Apr 17, 2019)

The US Army may very well have thought the StG 44 wasn't up to par or had bad features. 

Mistaken or not that is a very different thing than ignoring it or having no reports/tests on it.

That is the problem with some of these claims for German proximity fuses. Few, if any, notes or reports on their existence, as opposed to the reports being flawed or inaccurate.


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## tomo pauk (Apr 17, 2019)

Shortround6 said:


> The US Army may very well have thought the StG 44 wasn't up to par or had bad features.
> 
> Mistaken or not that is a very different thing than ignoring it or having no reports/tests on it.
> ...



StG 44 was not up to par??
Apart from semi-auto rifles, German small arms issued were either equal or superior than those of US Army & Marines.


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## P-39 Expert (Apr 17, 2019)

What is the smallest shell that would take the VT fuse?


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## tomo pauk (Apr 17, 2019)

P-39 Expert said:


> What is the smallest shell that would take the VT fuse?



In ww2, it was the 90mm IIRC.


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## Shortround6 (Apr 17, 2019)

tomo pauk said:


> StG 44 was not up to par??
> Apart from semi-auto rifles, German small arms issued were either equal or superior than those of US Army & Marines.




The US was not going to entertain the idea of a less than full powered rifle for nearly 15 years after the end of WW II. 
Rightly or wrongly, that is the fact of the situation. 
They may have thought the sheet metal receiver wasn't strong enough to stand up to the needs of military service. 
But that too is a matter of opinion and detail design. 

The US had left the type of sight the MP44 used behind several years before. Together with the short sight radius that made long range shooting a bit problematic. 

The US had plans for full auto M-1s with 20 round magazines. 






The German pistols were nothing special and the submachine guns MP38 and MP40 were also not anything out of the ordinary by 1944-45. 

It might be debatable if the MG 34 or MG 42 were really superior to the M1917 amd M1919 Brownings once you got them mounted on tripods and were using them for long range fire.
The MG 42 did well at a lot of things but may not have been the best in any one role.


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## Shortround6 (Apr 17, 2019)

P-39 Expert said:


> What is the smallest shell that would take the VT fuse?





tomo pauk said:


> In ww2, it was the 90mm IIRC.



In 1942 it was the 5in shell, this fell to the British 4 in shell by 1944 or so. Tomo may be correct about the 90mm but 3in shells had proximity fuses either right at the end of the war or in a few years after. (prototype 3in gun with auto loader firing in Sept 1945) By the 70s or early 80s the 40mm Bofors had proximity fuses. 

I don't know if any VT fuses were used by 3in/50 manual guns in service in WW II, they were certainly used post war.


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## tomo pauk (Apr 17, 2019)

I've started the new thread about infantry weapons


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## Shortround6 (Apr 17, 2019)

A History of US/Allied proximity fuses is here. 
Radio Proximty (VT) Fuzes 

there was a 3in fuse issued in May of 1944 but it wasn't very good and was replaced by a new fuse in Nov 1944

Please note the difficulties in getting what was essentially the same basic design to work in a variety of guns and conditions and some of the difficulties in going from prototypes to mass production.


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## fliger747 (Apr 17, 2019)

Unfounded opinion... 

VT fuses would not be terribly effective against very high altitude aircraft, aircraft being too far away for that many shells passing within the lethal triggering distance. Far more effective for point defense such as an airfield or ship for protection against low to medium altitude targets. Chances of approaching the target within the lethal distance excellent for aircraft fo instance heading toward you at several thousand yards.

Unfounded opinion! : )


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## Brooke (Apr 18, 2019)

pattle said:


> Germany was only still developing the proximity fuse at wars end after its development had been interrupted by a Hitler order around 1941. The proximity fuse was used with great effect by the Allies, most notably against the V1 flying bombs against which it was highly successful. The Americans were very mindful of the Germans reverse engineering proximity fuses and would at first not allow their use over enemy held territory through fear of a dud being captured. Proximity fuses were later used against ground targets with devastating effect and are generally considered to be one of the major inventions to come out of World War Two.
> German anti aircraft batteries concentrated their fire into a box and relied on timed fuses which were timed to exploded at a pre-determined altitude with the hope and expectation that shell splinters would destroy the oncoming enemy aircraft. If the Germans had of had proximity fuses fitted to their anti-aircraft shells then presumably this would have made them far more effective as the fuse itself would have exploded the shell upon detecting the presence of a bomber.
> Obviously the Allies had seen for themselves just how effective proximity fused shells were against the fast moving flying bombs and they would have been more than a bit concerned about the safety of their slow moving four engine bombers should the Germans had developed their own.



There are many flavors of proximity fuzes (a fuse is an electrical device, a fuze is used to set of explosives). One of those flavors is if the projectile rotates or not. Fuzes for antiaircraft missiles are a different animal from gun projectile fuses. For more on that see: China Lake Patents


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## Hairog (Apr 22, 2019)

These might be of interest.

Here



 https://drdo.gov.in/drdo/pub/monographs/Introduction/Proximity_Fuzes.pdf




And Here Radio Proximity Fuzes

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## JAG88 (Apr 27, 2019)

Sorry for the delay.



tomo pauk said:


> Any chance to provide a doc or two about US Army testing and/or opinion of the StG44?



A useful way into this topic is once again to look at US military
appraisals of the rifle, this time from the War Department’s Tactical and
Technical Trends series. The following report was published in April 1945,
by which time the Sturmgewehr had been in circulation for some time.

"In their attempts to produce a light, accurate weapon having
considerable fire power by mass production methods, however, the
Germans encountered difficulties which have seriously limited the
effectiveness of the Sturmgewehr. Because it is largely constructed of
cheap stampings, it dents easily and therefore is subject to jamming.
Although provision is made for both full automatic and semiautomatic
fire, the piece is incapable of sustained firing and official German
directives have ordered troops to use it only as a semiautomatic
weapon. In emergencies, however, soldiers are permitted full automatic
fire in two- to three-round bursts. The possibilities of cannibalization
appear to have been overlooked and its general construction is such
that it may have been intended to be an expendable weapon and to be
thrown aside in combat if the individual finds himself unable to
maintain it properly.

The incorporation of the full automatic feature is responsible for a
substantial portion of the weight of the weapon, which is 12 pounds
[5.4kg] with a full magazine. Since this feature is ineffectual for all
practical purposes, the additional weight only serves to place the
Sturmgewehr at a disadvantage in comparison to the U.S. carbine
which is almost 50 percent lighter.

The receiver, frame, gas cylinder, jacket, and front sight hood are
all made from steel stampings. Since all pins in the trigger mechanism
are riveted in place, it cannot be disassembled; if repair is required, a
whole new trigger assembly must be inserted. Only the gas piston
assembly, bolt, hammer, barrel, gas cylinder, nut on the front of the
barrel, and the magazine are machined parts. The stock and band grip
are constructed of cheap, roughly finished wood and, being fixed,
make the piece unhandy compared to the submachine guns with their
folding stocks.

The curved magazine, mounted below the receiver, carries 30
rounds of 7.92-mm necked-down ammunition. The rounds are
manufactured with steel cases rather than brass; inside the case is a
lead sleeve surrounding a steel core. With an indicated muzzle velocity
of approximately 2,250 feet per second [76.2m/sec] and a boat-tail
bullet, accuracy of the Sturmgewehr is excellent for a weapon of its
type. Its effective range is about 400 yards [366m], although the
Germans claim in their operating manual that the normal effective
range is about 650 yards [594m]. The leaf sight is graduated up to
800 meters (872 yards). (US War Dept 1945)

From an Osprey title, "German Automatic Rifles 1941-1945", McNab

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## tomo pauk (Apr 28, 2019)

Thank you very much for the excerpt.


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## Shortround6 (Apr 28, 2019)

I too, add my thanks.

It is interesting and does open up a few points.

It is speculation on my part but the US criticism of the weapon itself ( and there appears to be very little discussion/criticism of the concept) seems to be on it's construction which may be understandable in view of the US fighting a global war. Using disposable weapons (instead of repairable ones) in combat areas 3-6000 miles away from the factories may impose a logistical burden that outweighs the manufacturing burden? I don't know, just suggesting it. 

another point (and one that is common to many of these old evaluations) is that the term "effective range" is never defined. Perhaps the writer/s and reader/s of these reports understood what was meant at the time but 40-80 years later we are in the dark.
does it mean the rifle/ammo can put one shot in ten on a 6 ft x 6ft target at that range? or three out of ten? Or is it 4 ft by 4 ft target? No mention is made of how the weapon is being fired, Kneeling by average shot or laying down by expert shot.
The variables go on and on. 
Again I say , the writer/s of these reports may have been familiar with the test/evaluation procedures/criteria of the time the report was written but for modern readers we all have our own idea of what "effective range" might be leading to a lot of arguments that can never be resolved. 

I would also note that the effective range of a cartridge can vary considerably from the effective range of a rifle/machine gun it is fired out of.

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## JAG88 (Apr 28, 2019)

They may be criticizing the durability of the weapon but... its a wartime weapon, they and their users dont last that much, what is the point to make a weapon that would last for years?

Make it cheap, make it fast.

I think everyone here have seen videos of full auto StG 44s and know the statement about full auto to be incorrect.

The quip about part interchangeability is a valid one but it is the first time I have heard something of the sort.

In general, I think it is normal and human to look down on the weapons of the defeated enemy, and that could cause some people to overlook otherwise interesting developments as in this case... which was the point of bringing up this example in the thread.

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## ThomasP (Apr 29, 2019)

Hey guys,

I figure most of you are already aware of this, but in case you are not.

A large part of the reason that the UK and US did not consider a copy of the StG44 worth pursuing was the ammunition situation.

The UK had been contemplating changing over to an intermediate round (~7mm) since before WWI, but the war intervened. At the end of WWI the UK had over a billion rounds of their .303 ammo. Experiments with an intermediate round (.280) continued and after WWII the UK was testing various assault type rifles, including a machined/forged receiver bullpup weapon with detachable 20-round box magazine (the EM-2) which was their choice for development. When NATO came along the UK tested various entries for their new rifle and the FN FAL won, primarily due to the fact that the EM-2 would not be readily adaptable to the 7.62mm NATO round (basically a shortened case .30-06 ballistically). The FN FAL was a selectable fire (semi- and full-auto) machined/forged receiver weapon with a 20-round detachable box magazine. The UK found that the FN FAL in full automatic fire to be only marginally controllable using the 7.62mm NATO round, that full automatic fire was unnecessary operationally, and ordered the weapon into production as a semi-automatic rifle.

The UK did not ignore or denigrate the StG44, they simply already had a design (which evolved into the EM-2) for an assault weapon that they considered superior to the German assault weapon. Then they most likely made the right decision and adopted the FN FAL, which remained the standard issue rifle for the UK for 35 years, and remains on the limited standard list today (I think).


The US had been contemplating a switch to an intermediate round (~7mm) since the end of WWI. At the end of WWI the US had somewhere over a billion rounds of .30-06 ammo. The US was again contemplating a switch to an intermediate round in the 1930s, with the M1 Garand originally intended for the .276 caliber, but WWII intervened and the M1 Garand entered service in .30-06 caliber. At the end of WWII the US had a several billion rounds of .30-06 ammo on hand. After WWII the US decided on a selectable fire weapon, what eventually became the M14, using the .30-06 round. The US continued development and when NATO came along, the US used the M1 Garand as the benchmark to beat. There were several entries into the competition but in the end it came down to the M14 and FN FAL. The FN FAL won on points but the M14 was chosen. The M14 was a selectable fire (semi- and full-auto) machined/forged receiver weapon with a 20-round detachable box magazine. The US found the M14 in full automatic fire to be uncontrollable using the 7.62mm NATO round.

The US did not ignore or denigrate the StG44, they simply designed an assault type weapon using the .30-06 round (originally), of construction considered superior to the German assault weapon, and to a different set of operational requirements (i.e. that their rifle use the same ammunition as their light and medium MG).


Interesting fact, at one point in time the FN FAL was the weapon of choice of more than 90 nations (more than ever used the AK-47 or its variants). FN used that statistic in their advertisements.


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## JAG88 (Apr 29, 2019)

ThomasP said:


> Hey guys,
> 
> I figure most of you are already aware of this, but in case you are not.
> 
> ...



The British realized the Germans were onto something and the first development, the EM-1 was made by Korsach, a Polish refugee, which used features from the FG-42, it even fired 8mm Mauser and used the FG42 sights, in a bullpup configuration. There was another EM-1 by Thorpe, using the mechanism of the German Gerat 06 and finally the EM2 designed by another Polish refugee, both in the bullpup configuration pioneered by Korsach, which was the weapon finally adopted.

They didnt have a design prior to the StG44, their prototypes were often based on German weapons, but in the end decided to adopt the Polish designed weapons.




> The US had been contemplating a switch to an intermediate round (~7mm) since the end of WWI. At the end of WWI the US had somewhere over a billion rounds of .30-06 ammo. The US was again contemplating a switch to an intermediate round in the 1930s, with the M1 Garand originally intended for the .276 caliber, but WWII intervened and the M1 Garand entered service in .30-06 caliber. At the end of WWII the US had a several billion rounds of .30-06 ammo on hand. After WWII the US decided on a selectable fire weapon, what eventually became the M14, using the .30-06 round. The US continued development and when NATO came along, the US used the M1 Garand as the benchmark to beat. There were several entries into the competition but in the end it came down to the M14 and FN FAL. The FN FAL won on points but the M14 was chosen. The M14 was a selectable fire (semi- and full-auto) machined/forged receiver weapon with a 20-round detachable box magazine. The US found the M14 in full automatic fire to be uncontrollable using the 7.62mm NATO round.
> 
> The US did not ignore or denigrate the StG44, they simply designed an assault type weapon using the .30-06 round (originally), of construction considered superior to the German assault weapon, and to a different set of operational requirements (i.e. that their rifle use the same ammunition as their light and medium MG).



The FG-42 proved better than the Garand derivative they had adopted (the T20E2, later cancelled) but they were stubborn and developed yet another Garand derivative, the M14...

They did amalgamate 2 German weapons to make their M60 LMG though.


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## BiffF15 (Apr 29, 2019)

ThomasP said:


> Hey guys,
> 
> I figure most of you are already aware of this, but in case you are not.
> 
> ...




The FN is a very accurate but heavy rifle (common trait amount .308s of the period). I’ve had one since 1987, and it’s a nail driver.

Cheers,
Biff


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## Glider (Apr 29, 2019)

Meanwhile, back at the topic and the question regarding Proximity Fuses. Assuming that the German forces had both the design and ability to produce them in the numbers needed, then I don't see how the allied heavy bomber tactics and the assault as we know it could have continued. 
German AA guns were very effective and the typical US box formation an ideal target. At night the radar guided guns would have been far more effective and heaven knows they were dangerous enough as they were. Read any narrative on the experiences of RAF bomber crews and that is loud and clear. 

To pretend that somehow the allies could have continued is almost a fantasy. Losses would have significantly increased and something would have needed to fundamentally change and I cannot see what that would be.


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## Shortround6 (Apr 29, 2019)

Glider said:


> Meanwhile, back at the topic and the question regarding Proximity Fuses. Assuming that the German forces had both the design and ability to produce them in the numbers needed, then I don't see how the allied heavy bomber tactics and the assault as we know it could have continued.



That rather depends on what type of proximity fuse the Germans used. 

The British/American proximity fuse was pretty simple device (in theory) that was a miniature radio/radar transmitter and receiver. The fuse started transmitting shortly after leaving the barrel. The Receiver simply listened for the return signal (transmitted signal reflected off target) and when the return signal reached a certain value/strength the fuse detonated. the system was pretty dumb in the sense that there was no real coding or any means of identifying the signal source. Any radio, if transmitting on the right frequency that got enough energy to the fuse receiver antenna would cause the fuse to detonate. 
This was one reason for all the security and not using it over land. Not only the fear of it being copied but the fear that counter measures could be worked out and put into place in fairly short order. 
The fuse transmitter was pretty weak and transmitted in pretty much all directions (any gaps were due to shell shape?) and the reflected energy was lot smaller. An aircraft mounted transmitter operating on the same frequency could be a lot more powerful and overload the fuse receiver (reach the expected signal strength needed to trigger the fuse) when the shell was still hundreds (if not thousands) of feet away. 
The Americans had figured this out and built prototype "jammers" before the fuse went into service in large numbers.

Most any proximity fuse (of the time) can be defeated in the same manner. Use a strong enough signal to swamp the sensor and trigger the fuse early. 

Modern fuses may have gotten smarter and use some sort of code in the signal so the receiver can tell the difference between it's own matching transmitter and transmitters innearby shells or enemy transmitters trying to spoof/jam the frequency band.

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## ThomasP (Apr 29, 2019)

Hey JAG88,

I am not sure but I think you misunderstood what I was trying to say. Also, I believe we were talking about the StG44, not the FG42.

My point is that the UK and US did not ignore or denigrate the StG44 in any way due to its being a German weapon. They did not say the StG44 was worthless. They simply had their own requirements (smarter or not), which the StG44 did not meet.

If it helps to understand what I am saying, ask yourself the following questions:

1. Should the UK and US have discarded their rifles and SMGs at war's end, along with the several billion rounds of ammunition, and immediately started an emergency production program for the StG44? If so, why??

2. What reason did the UK and US have in 1945 to decide they should introduce another caliber of ammunition? Remember, one of the main reasons the US did not adopt the .276 or similar round was a requirement that their primary infantry rifle use the same ammunition as their light and medium MG. (It should be noted that a debate similar to this is going on today in the US armed forces.)

3. Did you ever read any reports from WWII where Allied soldiers said things like "Oh my God in heaven, here come the sturmtruppen with their StG44s, run away!! Run away!! Ignore the troops with the K98 and all the other German infantry weapons, they cannot compare to the effectiveness of the StG44." or "No Fred, do not advance, your ______ (insert any infantry rifle or SMG in the blank area) is no match for their StG44. Go over there and advance into the K98s, MG38s, MG42s,... At least you will have a chance to live!" You can imagine this being said in the King's English, American English, French, Russian, or any other language you choose - if you can keep a straight face when saying it yourself, let me know. To be fair, I would challenge anyone to do the same concerning modern infantry assault rifles as well.

I may have been unclear as to the time frame of the selection of the M14, EM-2, FAL, etc. I meant that by the time the UK and US were ready to adopt a new weapon and associated ammunition (~1950, at the beginning of the NATO standardization process) they already had designs they considered better for their requirements. And yes, some of those designs used bits and pieces of other nations designs, including German designs such as the StG44, FG42, MG42, etc.

Your point of making the weapon cheap is valid to a certain extent. For certain it would apply to a war-time army that is in dire straights production-wise. (I started to say ...and/or already losing the war, but that by its self negates the value of the concept.) The problem with this concept is that an army spends most of its time in peace, not war. If you make the weapons cheap you have to replace them more often, with the replacement cost exceeding the difference in any savings due to a low unit cost. (It should be noted that a debate similar to this is going on today in the US armed forces.)


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## ThomasP (Apr 29, 2019)

Back to the original topic,

I think maybe the way to look at this question is as follows:

Lets assume that only 1 out of 1000 non proximity fuse rounds hit a bomber in the daytime. Now lets say that using proximity fuses (similar to the Allied fuses or not) increases the effective hit rate to 2 out of 1000 rounds. That small increment doubles the loss rate for the Allied bomber offensive. Could the bomber offensive have been maintained with those loss rates? Please note that it does not matter what the actual number of rounds it took to shoot down a bomber - it could be 1 out of 2000, 3000,...10,000 - by increasing the hit rate to 2 out of xxxx rounds you double the loss rate for the bombers.

I do not think the bomber offensive could have been maintained in the face of double the losses. It would probably have had to be reduced or halted until countermeasures were worked out, similar to what happened to the US daytime bomber offensive in 1943.


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## bbear (Apr 30, 2019)

Glider said:


> Meanwhile, back at the topic and the question regarding Proximity Fuses. Assuming that the German forces had both the design and ability to produce them in the numbers needed, then I don't see how the allied heavy bomber tactics and the assault as we know it could have continued.
> German AA guns were very effective and the typical US box formation an ideal target. At night the radar guided guns would have been far more effective and heaven knows they were dangerous enough as they were. Read any narrative on the experiences of RAF bomber crews and that is loud and clear.
> 
> To pretend that somehow the allies could have continued is almost a fantasy. Losses would have significantly increased and something would have needed to fundamentally change and I cannot see what that would be.





ThomasP said:


> Back to the original topic,
> 
> I think maybe the way to look at this question is as follows:
> 
> ...



I think the year is crucial. In 1943 IIRC the flak system was intact, the park of guns in good order, the bombers mostly on RAF night operations. For his period the figure I remember is 3,300 rounds per aircraft destroyed. In 1944 the guns were less well served, the targets greater in number including many in formation and daylight. So a number of factors involved. I have no rounds per destroyed target for this period. In 1945 the Luftwaffe was a nearly dead duck, looking a bit peaky anyway. But the efficiency of the huge investment* had deteriorated *(15,000 '88's for one). A number were being knocked out in ground attacks.

The anti-aircraft fire caused about half of all losses during 1944, much less by proportion and much less by absolute numbers in 1943, much more by proportion and much less by absolute number in 1945 according to research on these figures https://www.afhra.af.mil/Portals/16.../AFD-090608-039.pdf?ver=2016-09-02-113908-487 shown here https://www.quora.com/Of-the-Allied...d-to-German-fighters-and-AA-fire-respectively .

So depending crucially on the date these nominal, imaginary, copy proximity fuses came into play for Germany the result could be devastating in 1944, at least at first. But after a period of weeks to hand build enough jammers we'd be back in business, I think. The researchers had already got their prototype countermeasure within 2 weeks of being asked for one.


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## Glider (Apr 30, 2019)

Shortround6 said:


> That rather depends on what type of proximity fuse the Germans used.
> 
> The British/American proximity fuse was pretty simple device (in theory) that was a miniature radio/radar transmitter and receiver. The fuse started transmitting shortly after leaving the barrel. The Receiver simply listened for the return signal (transmitted signal reflected off target) and when the return signal reached a certain value/strength the fuse detonated. the system was pretty dumb in the sense that there was no real coding or any means of identifying the signal source. Any radio, if transmitting on the right frequency that got enough energy to the fuse receiver antenna would cause the fuse to detonate.
> This was one reason for all the security and not using it over land. Not only the fear of it being copied but the fear that counter measures could be worked out and put into place in fairly short order.
> ...


I acknowledge what you say but as the Germans would be over their own ground the probability of the allies getting the required information would be at best limited. The time to design develop and issue the 'jammers' would be significant. Plus I always have a certain level of caution of magic solutions such as jammers, thinking of Vietnam where technology often didn't deliver the promised solutions.


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## bbear (Apr 30, 2019)

Glider said:


> I acknowledge what you say but as the Germans would be over their own ground the probability of the allies getting the required information would be at best limited. The time to design develop and issue the 'jammers' would be significant. Plus I always have a certain level of caution of magic solutions such as jammers, thinking of Vietnam where technology often didn't deliver the promised solutions.


From this account Radio Proximity Fuzes the jammer was to be the AN/APT4 as -already- eventually fitted in up to 200 B24 & B29's.​Photograph here​CW Magnetron Jammers​Described here​Full text of "Graphic Survey Of Radio And Radar Equipment Used By The Army Air Forces"​as​​
AN/APT-4 : Army & Navy Aircraft Radar Transmitter - 4th in series. A design number not a manutacturer's desi]gnation


Radar Set AN/APT-4 is an airborne magnetron
radar barrage or spot jammer fcr use against German
radar systems such as the Rhubarb, Liechtenstein and
Wurzburgs operating in the frequency range of 150 to
770 mc. A liquid cooled magnetron, GL-5J30 or GL-
5J29, is used as an oscillator, resulting in simple tun-
ing controls, and high efficiency. The transmitter in-
volves simple components without critical adjustments.

The transmitter is continuously tunable in flight,
if necessary, over the complete frequency band. Two
tuning adjustments are necessary. In ordinary use the
transmitter frequency will probably be set on the
ground and three or four sets staggered to cover the
entire band.

Power is obtained from a 80/115 volt, 400-2600
c.p.s., a-c source and 24 volt d.c. source. The power
input of 1500 watts produces an output of 200 watts over
the frequency range. The transmitted signal is a ran-
dom noise modulated signal designed to jam the enemy
signal in the frequency range of the transmitter.

Production of this equipment started in June 1944
Army Supply Program Requirements as of 30 April
1944 indicates no equipment for the calendar year 1944
and 300 for 1945.

it weighed 230lbs range 2 miles?
i understand that possibly 100 units were built and installed of the Stromberg Carlson prototype design in the photo

According to this source Tube: USN-5J29 – PocketMagic There were 2,000 plus made of the GE main production type though I don't yet know when 
You would need 4 per formation (to cover the frequency range 180 to 220 MHz)


So a shortish delay think.​

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## DerGiLLster (May 11, 2019)

Anybody have anymore information about electrostatic fuzes for AAA? Those seem to be the best bet for Germany to increase the effectiveness.

Anyways, I guess if Germany does manage to succeed in fielding a proximity fuze and figuring out how to defy the countermeasures(science in warfare is always back and forth), then it would be fair to say this would make bombing Germany much more difficult.

Wonder how it would play out once the A-Bomb comes in? Do they take the risk dropping it, or are too scared due to having sustained too high bombing losses?

Maybe such naval guns be optimized for AAA on land, sorta like the Beehive rounds Japan produced. That thing could have an effective range of 100 meters, but was lacking most likely due to a proximity fuze.


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## Glider (May 11, 2019)

Maybe I am a sceptic as I worked in IT for many years and theory and tests tend to differ from reality, in particular in the early days. I cannot get the promised, tested performance vs reality of the guided missiles in Vietnam out of my head.

I should add that my niche were projects that had gone wrong, so pardon my caution


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## Shortround6 (May 11, 2019)

Glider said:


> Maybe I am a sceptic as I worked in IT for many years and theory and tests tend to differ from reality, in particular in the early days. I cannot get the promised, tested performance vs reality of the guided missiles in Vietnam out of my head.



It kind of goes both ways. The proponents of the the German use of Proximity fuses tend to overlook that it took the US from the summer of 1940 till Jan 1942 to get over a 50% success rate on laboratory built test fuses. That was considered the minimum success rate needed before talking to a manufacturer to start setting up production. It wasn't until April of 1942 that a "live" test was conducted (full scale airplane suspended underneath a balloon.) Other difficulties needed work and first successful trial firing was accomplished in Aug 1942 from the USS Cleveland. Crosley started mass production with first issues to the Navy in Nov/dec f 1942 and first use against Japanese aircraft in Jan 1943. This fuse would fit the US 5in/38 ONLY. 
It took until Sept 1943 to get a fuse to fit the the British 4.5in shell and while it would fit the 5.25 in shell the firing characteristics of the 5.25in gun were not compatible with the fuse. 
A new smaller fuse had to be made in order to fit the British 4in gun and still leave enough room for explosives. These 4in shell fuses were first issued in Nov-Dec 1943 (?).
A similar fuse was adopted for the US Army 90mm AA gun in very late 1943. 

Perhaps the Germans could have developed a proximity fuse that worked in the 12.8cm flak guns, that doesn't mean it will fit in the 10.5cm flak guns ar that a fuse that works in the 10.5cm guns will work in the 8.8cm guns, especially the high velocity guns. 

There was also a world of difference between the proximity fuses of 1943-45 and the jammers needed to counter them and the electronics of the late 50s-early 60s. 
Even in the late 50s and early 60s missiles were being advertised as having the ability to home in on the source of a jamming signal if it was much stronger than the signal reflected form the target. SO you were getting into a several layer measure-counter measure battle instead of the simple one layer battle of WW II proximity fuse vs broadband (somewhat) white noise transmitter needed to counter them.


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## bbear (May 14, 2019)

Shortround6 said:


> It kind of goes both ways. The proponents of the the German use of Proximity fuses tend to overlook that it took the US from the summer of 1940 till Jan 1942 to get over a 50% success rate on laboratory built test fuses. That was considered the minimum success rate needed before talking to a manufacturer to start setting up production. It wasn't until April of 1942 that a "live" test was conducted (full scale airplane suspended underneath a balloon.) Other difficulties needed work and first successful trial firing was accomplished in Aug 1942 from the USS Cleveland. Crosley started mass production with first issues to the Navy in Nov/dec f 1942 and first use against Japanese aircraft in Jan 1943. This fuse would fit the US 5in/38 ONLY.
> It took until Sept 1943 to get a fuse to fit the the British 4.5in shell and while it would fit the 5.25 in shell the firing characteristics of the 5.25in gun were not compatible with the fuse.
> A new smaller fuse had to be made in order to fit the British 4in gun and still leave enough room for explosives. These 4in shell fuses were first issued in Nov-Dec 1943 (?).
> A similar fuse was adopted for the US Army 90mm AA gun in very late 1943.
> ...


Shortround6, thanks as ever. My impression was that the jammer wasn't broadband but rather swept frequency. All the power into one wavelength at a time, Makes sense to me.


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## wuzak (May 14, 2019)

ThomasP said:


> I do not think the bomber offensive could have been maintained in the face of double the losses. It would probably have had to be reduced or halted until countermeasures were worked out, similar to what happened to the US daytime bomber offensive in 1943.



You'd have to separate losses from flak and enemy fighters. And year.

The 8th AF lost more aircraft to fighters than flak in 1943, but from mid-to-late 1944 it was the other way around. 

In 1943 a significant increase in the loss rate would have been very detrimental to the 8th AF, and may have slowed operations, if not totally stopping them.

In 1944 the number of aircraft being sent and the number of reserve aircraft and air crew would have meant that loss rates would have had to increase substantially to have an effect on operations.

In 1944 a doubling of the loss rate would still have been a lower loss rate than in 1944.

In 1943 the Schweinfurt/Regensberg raid the losses were ~60 from 300 bombers, or about 20%. The second Schweinfurt raid was worse (77 bombers lost of 291).

In early 1944 there were a few raids with similar numbers of aircraft lost, ~60. However, there were as many as 1,000 bombers, or more, on these raids, which gave a much lower loss rate.

By 1944, as the Luftwaffe strength fell, the number of aircraft shot down reduced as well as the loss rates.

For the British night bombing the Luftwaffe night fighting force was significant in causing losses. Not sure of the balance between night fighters and flak, but the RAF expended a lot of resources in diversionary tactics to draw night fighters away from the intended target. From the development of _Window_, _Monica_ tail warning radar and radar detectors_, _to the deployment of the Light Night Striking Force.

Doubling flak effectiveness would not lead to doubling the loss of allied aircraft at the crucial point of the air war in the ETO, from mid 1943 onwards.


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## ThomasP (May 15, 2019)

Hey Wuzak,

re: "Doubling flak effectiveness would not lead to doubling the loss of allied aircraft at the crucial point of the air war in the ETO, from mid 1943 onwards."

Sorry, but I am not sure what you are trying to say here. By definition, if you increase the effective hit rate from 1 to two 2 it would double the loss rate per xxxx number of rounds. A direct hit is still a direct hit, a near miss with a time fuse or proximity fuse that takes down a bomber is still a near miss that takes down a bomber. Even if the average loss rate was only 10% the bomber offensive would be unsustainable. If the Germans had an effective fuse at the start of 1944, there is no reason I can think of that the losses would not have been around the 10% mark, at least until countermeasures were worked out or until the collapse of resistance due to the Russian advance and (possibly) an invasion by the UK and US.

I have read that about 2/3 of the losses at night by UK bomber command in the 1944 period (prior to the collapse of the Luftwaffe) were due to night fighters.


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## wuzak (May 15, 2019)

What I am saying is that doubling the losses from flak is not doubling the losses of the bombers.

That only works once the losses to fighters has gone to zero.

If the split between fighters and flak losses is equal, the loss rate would go up 50% if you double flak's effectiveness. If the split is 2:1 in favour of the fighters, the overall loss would go up 33%.

It also doesn't work if you double the number of planes shot down if they put up 3 or 4 times the number of aircraft. The loss rate would actually go down, even though your flak is more effective.

In 1944 the number of bombers ramped up quite significantly. To cause a 10% loss rate would require more than a doubling of flak effectiveness. The loss rates for the 8th AF fell from January/February to May/June, as the Luftwaffe suffered heavy losses.

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## ThomasP (May 15, 2019)

Hey Wuzak,

OK, I understand.

I was thinking that the loss rate to AAA was only 5% on average, hence doubling the effectiveness of the AA rounds would result in 10% losses. IIRC by mid-1944 the amount of AAA had more than tripled from mid-1943, and the number of rounds fired had more than tripled (I think it was actually more like 6 times the number of rounds but I do not remember for sure. Maybe someone else has better numbers for this?). Had the number of US bombers flying over the defended targets increased to the ratio point that you are thinking? I do not know. I have never seen a detailed report on the number of rounds fired at the bombers - i.e. how many vs the US daytime raids, as opposed vs the UK night time raids, how many bombers were in the air per number of rounds fired, etc. It would be interesting to find out.


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## gordonm1 (May 23, 2019)

This thread raises my interest in what proximity fused weaponry was used on infantry in WWII and what effectiveness it had. Any links are appreciated.
I don't have much knowledge base but for my .02 $, I think Germany was going to get rolled over on the ground no matter what happened so only timing would be affected by more use of proximity fuses. They would be helpful in torpedoes too but I doubt enough to affect the outcome.

The revolutionary fuse that won World War II 

Artillery Proximity Fuses 

Edit: A couple links found with general discussion fit for newbys like me.


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## Zipper730 (May 23, 2019)

What was the typical loss rate to night-fighters?


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## bbear (May 28, 2019)

gordonm1 said:


> This thread raises my interest in what proximity fused weaponry was used on infantry in WWII and what effectiveness it had. Any links are appreciated.
> I don't have much knowledge base but for my .02 $, I think Germany was going to get rolled over on the ground no matter what happened so only timing would be affected by more use of proximity fuses. They would be helpful in torpedoes too but I doubt enough to affect the outcome.
> 
> The revolutionary fuse that won World War II
> ...


Here's a few links
 8 minute introduction places and faces
http://www.bombfuzecollectorsnet.com/userimages/radio proximity vt fuzes.pdf authorised version of events facts and figures
Proximity Fuze History Southwest Museum of Engineering,Communications and Computation# history context
https://www.jhuapl.edu/techdigest/views/pdfs/V02_N1_1962/V2_N1_1962_VTfuze.pdf history with a telling picture on p22*
https://www.drdo.gov.in/drdo/pub/monographs/Introduction/Proximity_Fuzes.pdf post war discussion from ally. see Section 1.7 A Striking Combat Success


effectiveness: not measured in the field in period as far as I know,

your next resources may be to consult "The Deadly Fuze" [by Ralph B Baldwin


* if you look at the photo on page 22 you can estimate that VT fuzes that worked detonated at designated height +/-a few feet. At say 600m/sec flight speed that's about equivalent of a timed fuze with perhaps 10ms standard error (+/-6ft). Typically I believe that the best mechanical timed fuze could only achieve +/- 0.1 sec or +/- 60 meters.

That's what makes the VT fuze interesting to me. It did with accuracy and common c;lay troops, an artillery job that any fully educated experienced artillery man would be proud of.

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## ThomasP (Jun 2, 2019)

Hey guys,

(from 'The Bombing War: Europe 1939-1945' by Richard Overy)

During the Battle of Britain and The Blitz, over the night campaign from July 1940-June 1941, the UK AA guns were considered to have shot down 170 aircraft with another 118 damaged. 

In September 1940 alone over 260,000 AA rounds were fired. The Air Ministry estimated that the number of AA shells per shootdown began at about 6,000 per aircraft in the autumn of 1940, reducing gradually to 3,195 to April 1941. Improved radar, improved/increased searchlight units, and improved organization and methodology further reduced the number to 1,830 per shootdown in the spring of 1942 (the best for the UK prior to the introduction of the proximity fuse).



(from 'Archie, Flak, AAA, and SAM' by Kenneth P. Werrell which can be found on the dtic website)

(https://apps.dtic.mil/dtic/tr/fulltext/u2/a421867.pdf)

(re UK AA effectiveness)

Starting in October 1940 the UK began deploying radar for aid in shooting at night. The rounds per shootdown went from 30,000 in September 1940 (when German night bombing began), to 11,000 in October 1940, to 4,199 in January 1941.

Against the V-1, the proximity fuse was considered 5x more effective than timed or contact fuse.

(re German AA effectiveness)

In the ETO the USAAF credited the German AA with shooting down 7,821 out of 18,418 aircraft lost on combat sorties, with 6,800 lost to enemy fighters, and 2,179 lost to operational or unknown causes.

After the war the US did a study that found if the Germans had used proximity fuses, the heavy FlaK would have been 3.4x as effective. This would have made operations by the B-24* "impractical" and operations by the B-17 "very hazardous".

*My note. The 88mm FlaK 18/36/37 made up ~60% of the German heavy AA during WWII. The effective ceiling of this gun was considered ~26,000 ft, about equal to the the practical operating altitude of the B-24.



(from 'German Ground-Based Air Defenses, 1914-1945' by Edward Westermann.)

The Germans estimated ~3,000 rounds per shootdown in 1943.

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## bbear (Jul 10, 2019)

A "new" original source, for comments. I rate this highly as it is from government authority, near contemporaneous and gives a clear account of the function of the circuit which is precious as no one nowadays can really confidently say they know enough about Vacuum Tube design to be able ton criticize Butement's design. At least you would struggle to find one such. I think.

https://nvlpubs.nist.gov/nistpubs/sp958-lide/059-062.pdf 
the circuit explanation starts at the top of Page 60 (the second page in this document)

the authortative work it cites Radio Proximity Fuzes for Fin-Stabilized Missiles appears to be seminal as when I use that string in a search pattern a wealth of 'new' material appears. New to me that is - for comment as I say.

one such "new work" published 1946 has a thorough treatment of the electronics in chapter 9. I have s yet not read it. I'm just a bit excited.
VT Fuzes For Projectiles and Spin-Stabilized Rockets - OP 1480


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