Talk:Proximity fuze

Land Variants?
Uh how would a proximity fuze of the type described here work on land? It would seem to me that a radar altimeter-style fuze could work, but one which depends on doppler shift to detonate wouldn't do so before impacting the ground. Ground bursts are not the most effective artillery strategy, and the most effective altitude for an airburst increases proportionally to the size of the shell (the extreme end is found with atomic bombs, which are mentioned here). So is there something I'm not seeing? Otherwise the article should be updated to reflect this. -User:Lommer | talk 19:44, 8 December 2005 (UTC)


 * Proximity fuzes used against targets on land function at a height above the ground. As a fuze approaches the ground the radio wave are reflected off the ground. The frequency changes as the fuze approaches the ground and this is used to determined the Height of Burst (HOB). The HOB can also vary based on the surface type. For example a field would reflect the waves differently then a parking lot. This link has more details.
 * --HeKeRnd 16:01, 12 December 2005 (UTC)
 * Archived copy of that dead link. Pigkeeper (talk) 14:05, 5 November 2019 (UTC)

I understand how a modern radar altimeter works (time delay from pulses), but I don't see how one could employ doppler shift to build an altimeter unless one was using it to calculate velocity and then integrating that backwards to some reference altitude to determine position. The way the article reads now it implies that doppler shift is still being used. -User:Lommer | talk 07:01, 13 December 2005 (UTC)

I think the confusion comes from the articles example for doppler shift. Doppler shift comes from the relative motion of something sending out the wave (sound or radio) and the receiver. The passing train example is very common, but in this case it muddles the term. Doppler shift is occurring even before the train passes. The link given by HeKeRnd is very good, and my understanding is that the signal bouncing off the target is a different frequency than the original signal, and mixing these two produces a low-frequency signal which will detonate the shell when the target is close enough to create a strong signal reflection. The shell doesn't need to pass the target. 69.110.48.22 00:05, 2 April 2006 (UTC)

Misspelling
I'm confused. The word Fuse is clearly misspelled (at least the English version of this word). Why is this article here and why does Proximity Fuse redirect here? Nevermind. I spoke before I had the facts. Fuze seems to be acceptable. I don't understand it but I have to accept it. James084 13:48, 23 December 2005 (UTC)

Bush?
Bush who? George Bush?70.225.179.182
 * The Bush mentioned, Vannevar Bush, is unrelated to the Bush political family. Bogsat 13:31, 30 January 2006 (UTC)

How they found which vacuum tubes would survive the setback of firing from an artillery piece.
I had a conversation with Laurance Halfstad a few years before he passed away in which I asked him how they determined where to start in putting a radio transmitter and receiver into the nose cone of an artillery shell when all they had were vacuum tubes to work with.

Answer: They went to a radio shop in London and purchased an assortment of vacuum tubes which they then took to the top of the Tower of London and dropped them from the top. The tubes which survived gave them a starting point to the design of tubes strong enough to survive the setback of being fired out of an artillery piece.

I received a copy of the book "The Deadly Fuse" and have read it cover to cover.

It is a fascinating account of the developement and fielding of a device to help win WW2. —The preceding unsigned comment was added by Don2158 (talk • contribs) 17:17, 24 January 2007 (UTC).


 * IIRC, the fuze contained a miniature radar transmitter, which was powered in production units by an Exide wet battery cell that contained acid inside a glass ampoule. When the shell was fired the shock of the firing shattered the glass allowing the acid to activate the battery and firing circuits. The fuze relied upon sub-miniature valves (vacuum tubes) that IIRC, were developed in the US by the Sylvania company.


 * Earlier attempts at producing a proximity fuze had used photo-electric cells, but they could be set off by passing birds, etc. The whole driving force for the fuze's development was anti aircraft use, i.e., large AA guns, which were, at the time being used to defend London and the other UK industrial cities, often with little effect.


 * Baxter's book on WWII technology ("Scientists Against Time") discusses this, and tells the story that the British were buying miniature tubes (for hearing aids) from WEC and RCA before the American proximity-fuze team realized they were meant for British experiments. The British focused on bomb and rocket fuzes, with requirements of about 100g acceleration.  The super-rugged fuzes for artillery (20,000 g) were developed later, in the USA. They worked with WEC and Raytheon on modifying their mini tubes to withstand the additional stress.  DonPMitchell (talk) 06:01, 23 May 2015 (UTC)

fuze vs. fuse
What happened? Why the hell has this been moved to an incorrect page name, and why was there no attempt at discussion beforehand? Andy Dingley (talk) 09:05, 14 July 2008 (UTC)
 * Merriam-Webster and the American Heritage Dictionary list fuze as a variant spelling of fuse. The traditional Google method puts "proximity fuze" at 16,000 hits compared to "proximity fuse" at 22,000 hits, so the "fuze" spelling is quite common in a military context, but still rarer than "fuse".  Fuse (explosives) also supports preferring "fuse": consistency with this would be a good principle.

--Maltelauridsbrigge (talk) 15:48, 15 October 2008 (UTC)


 * Fuse (explosives) actually supports "fuze" (as would be a better name for that article too), if you read it in sufficient details. "Proximity fuse" is way off the beam, even if there are plenty of civilian dictionaries that claim to be authoritative on the subject. Andy Dingley (talk) 16:06, 15 October 2008 (UTC)
 * What form do the ordnance manuals use ? Wouldn't that be the appropriate Wikipedia guideline here ? Dictionaries just reflect general usages, whereas in a specialised article su8ch as this I would expect it to use the terminology prevailaing in published specialized literature. Rcbutcher (talk) 05:52, 16 October 2008 (UTC)
 * "Fuze" In the literature of the field itself, this just isn't a question. Of course Wikipedia always knows better, unless it can find a pokemon fansite that agrees. Andy Dingley (talk) 09:42, 16 October 2008 (UTC)

THe Article on the Fuses states at the top, that this was developed by an american.

Seems strange that the British Had already done testing and protype fuses, before passing the techology. So it was actually developed by the British, Not an American.

For more information, See Churchill's Dairies to give you a time line, and on what was developed.

So can someone change that please. As it is an adent lie.

Sincerely

fenir 24/7/09 —Preceding unsigned comment added by 114.76.177.221 (talk) 12:18, 24 July 2009 (UTC)


 * I believe the confusion here is the difference between a laboratory concept and industrial production of a fuze capable of reliably functioning in a combat environment. The History section of the article credits British scientists with the original idea and laboratory prototypes.  The introduction emphasizes the accomplishments of United States industrial research and development at a time when the United Kingdom was hampered by wartime disruption of services and materials.  Readers accustomed to the journalistic style of newspapers may not realize the importance of later parts of Wikipedia articles. Thewellman (talk) 16:38, 24 July 2009 (UTC)


 * The fuze was working and could have been developed further in the UK, but at the time, Hitler was still planning on carrying out Operation Sealion so there was a distinct possibility of the UK being invaded. This was the main reason for the transfer of technology that was encapsulated in the Tizard Mission, to get the technology out of the UK so that production could be carried out in either Canada or the US. If Britain had been invaded then the war would have been continued from Canada, the necessary arrangements having been made some time before. The UK was perfectly capable of developing the fuze, but it would have taken longer, as the UK's electronics resources were taken up by normal radar development and similar. The fuze itself was a good example of Allied technological cooperation during World War II. —Preceding unsigned comment added by 213.40.251.192 (talk) 12:18, 30 October 2009 (UTC)


 * BTW, in explosives/munitions fuse = simple device, e.g., Cordtex, primacord, whereas fuze = complicated device, e.g. clockwork time fuze, anti-handling fuze. The two spellings simply differentiate between simple apparatus such as 'blue touch paper' that is lit on a firework, and the mechanically/electrically complex device used on a shell, aerial bomb, or missile.


 * Incidently, on a naval torpedo the fuze is usually known as a pistol due to 18th century naval demolition charges being fired using a flintlock pistol rigged to barrels of gunpowder and fired by a (usually long) string attached to the trigger. This is also why depth charges use a 'hydrostatic pistol' and not a fuze. — Preceding unsigned comment added by 86.112.68.219 (talk) 17:34, 5 July 2011 (UTC)

Doppler
The BuOrd 1946 ref has a nice description of the design. The ref describes doppler detection, but does not use the explicit words and glosses over some subtle design issues. The first tube is an autodyne stage that operates as an oscillator (to generate the transmitted RF signal and the local oscillator for detection), a mixer to detect the reflected signal, and an amplifier. The reflected signal is doppler shifted, mixed in the first stage (due to the nonlinearity of the transfer function; glossed over), and the difference frequency is selected at the plate of the Hartley oscillator and in subsequent stages. (In a normal Hartley oscillator, there is not be a plate load resistor; that shows the first stage is being used as an autodyne.) The BuOrd description further describes that a small band of difference frequencies are selected; those are the doppler shift frequencies. Doppler shift is not mentioned, but effect is described by changing distances and phase relationships. Glrx (talk) 07:00, 3 January 2011 (UTC)

Been awhile since i have been here...
For the wellman.

"The VT fuze concept in the context of artillery shells originated in the UK with British researchers (particularly Sir Samuel Curran[1]) and was developed under the direction of physicist Merle A. Tuve at The Johns Hopkins University Applied Physics Lab (APL)."

So this gives credit for the original concept ..to Britian and Sir S Curran....but was "developed" under the "direction" of M A Tuve at J.Hopkins. 4.5 years of uni, 2 degrees and a post grad later, and 2 years tutoring at uni, i'm pretty sure i can read. And the idea for the Prox fuse, was churchills. It was actually developed for AAA. But of course the principles where applied to all areas.

The entire project was completed by the british, war reserch labs. TRE umbrella, but called the war labs. Under order from churchill, the "completed" project was to be Quote: "transferred to the US, to be place into mass production". Reason being, the british had no more production lines avilable. So the US produced them initially, and may have developed them further, but the concept, and development for operational use was completed before transfer. And for $50 i will get you your own copy of the orders.

According to TRE, and Churchill, the project was finished. It only required, under the terms of information and tech sharing, to be "shared".

See.. Churchill war diaries, vol 2, Archive records British Library. War ministry records, Imperial war Museum & British Library, national archives.

PS: Fuse is queens English. From fus- 'poured, melted', from the verb fundere. Fuze is yankee.

verb 1 [with object] join or blend to form a single entity: intermarriage had fused the families into a large unit[no object] (of groups of atoms or cellular structures) join or coalesce. melt (a material or object) with intense heat so as to join it with something else: powdered glass was fused to a metal base [no object] : when fired in a special kiln, the metals fused on to the pot2 [no object] British (of an electrical appliance) stop working when a fuse melts: the crew were left in darkness after the lights fused[with object] cause (an electrical appliance) to stop working when a fuse melts. 3 [with object] provide (a circuit or electrical appliance) with a fuse: (as adjective fused) a fused plugnoun a safety device consisting of a strip of wire that melts and breaks an electric circuit if the current exceeds a safe level. — Preceding unsigned comment added by Originalfenir (talk • contribs) 03:44, 9 August 2011 (UTC)

And please, dont talk down to me. I dont read newspapers. Sincerely

fenir — Preceding unsigned comment added by Originalfenir (talk • contribs) 03:33, 9 August 2011 (UTC)

Mythical sources?
There appears to be some doubt CIOS report ITEM no 3 file no XXVI -1 even exists... Can somebody confrim? TREKphiler  any time you're ready, Uhura  08:31, 5 November 2012 (UTC)

German work?
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)

height above ground
I recall a story about the death of a US soldier in Vietnam. The author uncovered, after much effort, that the accidental death had occurred because an artillery round fired during the night had passed, due to negligence, overhead and close to a tree near the camp, which caused the shell to explode over the foxhole the soldier was sleeping in. My point in bringing this up is that I believe there is evidence that, in important cases, proximity fuses trigger when the shell is close to "something" on, or above, the ground, and that artillery officers as supposed to be aware of that. I think that emphasizing "height above ground" obscures this point. I am not sure what to say, but there must be a better, less misleading expression. --AJim (talk) 21:11, 11 March 2015 (UTC)


 * In most cases, the distance between the vegetation canopy and ground surface is less than the lethality radius of shell fragments to unarmored targets. Fuze function height will vary with several factors including projectile velocity and trajectory, and that height variation may similarly exceed the distance between the ground surface and vegetation canopy. Fuze sensitivity to the vegetation canopy varies widely in comparison to denser rock, soil, or water. I suggest emphasis on vegetation or other objects above the ground surface would be confusing except in conjunction with a description of relative fuze sensitivity; but it is difficult to find secondary sources for fuze sensitivity and variation. Thewellman (talk) 04:18, 12 March 2015 (UTC)

Soviet proximity fuze
Anyone know if the Soviets worked on this problem during the war. I know they had these very strange "rod tubes" designed for extreme stress, but not sure when that was done. DonPMitchell (talk) 06:11, 23 May 2015 (UTC)

developed or not developed?
the article says the British "developed" the VT fuze and in the next sentence says they didn't have the ability to develop it.

Some word besides "develop" would probably serve better in one of those sentences depending on what it was they could and couldn't do. — Preceding unsigned comment added by 23.119.204.117 (talk) 22:24, 3 August 2015 (UTC)
 * "develop" = invent or improve is kept; however Britain did not have a large enough industry to build it in quantity. I fixed it. Rjensen (talk) 00:32, 4 August 2015 (UTC)

Maximum acceleration and deceleration
Re these unsourced changes: acceleration was up to 20,000 $g$ as opposed to about 100 $g$ for rockets and one for dropped bombs.

This is not sourced by the source already there. Previously it stated "much less", which is correct.

I presume the editor's assumption (which fails WP:OR) is that free-falling gravity-dropped bombs are subject to a maximum acceleration equivalent to 1g, i.e. that of gravity vertically downwards. That's true when they're in storage on the ground. When dropped, they're now free-falling and so this will be less than gravity. However they also undergo a horizontal deceleration, or acceleration rearwards. For retarded bombs, this can be appreciable – much more than 1g. Andy Dingley (talk) 08:54, 3 October 2019 (UTC)


 * Ye gods. The rearward horizontal acceleration caused by the difference between the bomber's airspeed and the terminal velocity of the bomb in air? That's your cause for reversion? I find that claim almost incredible.
 * Riventree (talk) 09:18, 3 October 2019 (UTC)
 * Yes. I don't have figures for all of them, but some recent types decelerate at around 6g. Andy Dingley (talk) 09:25, 3 October 2019 (UTC)

Too much focus on WW2
Proximity fuses still exist and have developed a lot since WW2, yet the coverage in this article is so skewed towards WW2, an uninformed reader could assume they were only relevant during that war. Can we get some post war developments? Hammerfrog (talk) 18:59, 26 January 2020 (UTC)

I agree. Have added some cited information on acoustic technologies but, over all, the article is still heavily biased towards the famous (and very interesting) story of the WW2 Anglo American development of the VT artillery fuze.

I think there is a case for having the WW2 VT Fuze development in a separate article. Stivushka (talk) 18:47, 28 November 2020 (UTC)

Small Error - Battle of Liege?
Secion World War II, Subsection Deployment: It says "Patton credited the introduction of proximity fuzes with saving Liege" but this links to the 1914 battle of Liege. Also, Patton's major engagement as the VT shells were rolled out was in Bastogne, not Liege which was not affected by the battle of the Bulge.-- IP User 64.53.215.183 21:18, 23 August 2021‎

The link to the WWI Battle of Liege is wrong so I removed it. The Nazi plan for the 16 Dec 1944 assault that became the Battle of the Bulge: Day 3: reach the Meuse between Liège and Dinant. Liege was a target. There was no Second Battle of Liege because the Germans were turned back. I'll defer to Vannevar Bush and accept that Gen Patton credited stopping the Germans from reaching Liege to the introduction of the proximity fuse. -- Naaman Brown (talk) 00:44, 17 September 2021 (UTC)

Image captions
Only one of the image captions mentions the fuze type (magnetic). I believe the others are radio/radar -- could someone familiar with this update the captions? Thanks - SCEhard T  15:46, 10 January 2022 (UTC)

"5-10 times"
2good2b true? Apparently according to "Ammunition performance against kamikaze attacks in Philippines, Oct 44- Jan. 45. Source: Center of Naval Analyses, United States Navy: Defense Against Kamikaze Attacks in World War II and It's Relevance to Anti-ship Missile Defense (November 1970), Volume I, 75-76." It was close to 3x for VT and only using 5" guns, with worse than conventional results for 3". Gendalv (talk) 17:34, 18 February 2022 (UTC)

Mentioning of countermeasures?
Since this is an electronic device, it is susceptible to electromagnetic warfare such as jamming (e.g. ), shouldn't there be some mentioning of that? --Voidvector (talk) 06:49, 25 June 2023 (UTC)
 * this suggests that modern proximity fuzes may be made to be difficult to jam, but I don't think this source or yours are useful for supporting potential text in the article. We'd need reliable sources from a subject matter expert on the history, use and effectiveness, and I'm unaware of one. (Hohum @ ) 18:25, 25 June 2023 (UTC)

Emma Unson Rotor - filipina physicist who did research on the Fuze
Scientific American ran an article about Emma Rotor, a forgotten woman scientist who did significant research on the fuze. Perhaps this can be fleshed out and added to this article. Unfortunately, Scientific American does not go into much detail about her work.

https://www.scientificamerican.com/article/this-filipina-physicist-helped-develop-a-top-secret-weapon/ CosmicDragonRabbit (talk) 21:45, 22 January 2024 (UTC)

Science News published an article that goes into more detail regarding Emma Unson's contributions and publications: "Her work on 'Air travel required for release of arming cover' and on 'Measurement of dynamic propeller unbalance' are cited in the 1946 summary report of the Ordnance Development Division’s work on the proximity fuze, titled 'Radio Proximity Fuzes for Fin-Stabilized Missiles.'"

https://www.sciencenews.org/article/emma-rotor-filipino-math-teacher-wwii-weapons-fuse PaigePhault (talk) 18:03, 10 March 2024 (UTC)

No German proximity fuses in WWII
I was watching the video and went down the rabbit hole on FLAK guns. I was trying to figure out how proximity fuses worked. The Internet seems to provide a bit of conflicting information on whether Germany actually used proximity fuses during WWII or not. Some places seem to suggest that Germany had them, but they were not fully fledged proximity fuses as the allies had at the end.

This article refers to a source that say that they didn't, just wondering if this is conclusive or simply based on a single source? BFG (talk) 21:51, 28 January 2024 (UTC)
 * Germany had several types of proximity fuzes. What they didn't have were small, rugged fuzes capable of being fired from AA guns, or a production method to make fuzes in those numbers. They did have anti-aircraft missiles, albeit in very small numbers, and these used the complex and bulky fuzes.
 * These fuzes were documented in the 1945 reports on German equipment, although not all of this was public at the time, partly to maintain the secrecy of the VT fuze (but the missiles were reported quite openly and then went on museum display). Ian Hogg's books are the best and earliest open publication of them. Andy Dingley (talk) 23:01, 30 January 2024 (UTC)