Talk:Chaff (countermeasure)

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This excellent article, like others in Wikipedia and books (e.g. "Laurels for Priz Witgenstein", W.P.Roell, 1994), makes no mention of one fact: at least some Window wasn't just strips of aluminium foil - the back of the strip was matt black. I'm basing this on direct experience: during WWII in the greater London area, in the mornings we would find Window on the streets. Or was it Chaff, or even Düppel? My recollection is that the strips were maybe 10 inches long, so they may have been from RAF or USAAF aircraft training flights (the German radars used 50cm wavelength, right?).

But we know the Luftwaffe used Düppel over London after the Hamburg firestorm. Does anyone know if the matt black backed foil was Düppel, or could it have been Window or Chaff? And what would the purpose have been? Clearly the strips would only reflect from the shiny side, but they twisted and tumbled as they fell. Was this a means of further confusing the radar returns? Edetic 04:23, 6 August 2006 (UTC)[reply]

I believe the matt side is indeed, as you say, to further confuse the radar system. To take the analogy of lights that I've seen used, the aircraft is one light in the middle, say, and the chaff is a number of other lights. Your light gets lost in the middle, which is the principle of countermeasures. Now, if we have one side matt, it's going to be like everyone with those other lights not just holding them, but turning them on and off very fast. I'd bet you'd be a lot more confused in that situation than the former. And the Wuerzburg radar had a wavelength of 53cm, so your guess was very close! I'm pretty sure the U.S. chaff was purely metallic, and the same for Düppel. Therefore, perhaps it was Window? Could have been something that wasn't that widespread. A trial, if you like.

Dancraggs 01:29, 28 November 2006 (UTC)[reply

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Hello all. Excellent page. I believe the answer may lie here: [1] in the obituary of

explains that aluminised paper was used - with the added advantage that printed propaganda could be printed on the reverse! James Curran (talk) 13:11, 27 November 2007 (UTC)[reply]

There's an article on Window here: [2] with some info from the original manufacturers, the Sun Engraving Company, Ltd. The Window was made on a converted Baker Perkins magazine printing press, the black colouring being merely printed ink, which then had to be dried. The black colour BTW was just so that it did not show up if searchlights shone on it. — Preceding unsigned comment added by 86.112.68.219 (talk) 18:45, 9 July 2011 (UTC)[reply]

TRE developed three lengths of 'Window' for the three wavelengths in use by Germany, or thought likely to be used by Germany, 'Rope' - long-wavelength, 'Window' medium-wavelength, and 'Chaff', short- (centimetric) wavelength, with 'Window' being used predominately, as the German centimetric systems came to late in the war to be used in any numbers. Chaff became the predominant name post-war with the widespread use of microwave (centimetric) radars. — Preceding unsigned comment added by 80.7.147.13 (talk) 13:07, 1 January 2014 (UTC)[reply]

There was no link from there to here, so I added one. Graldensblud 00:37, 9 May 2007 (UTC)[reply]

I suggest that we replace this section with an overall topic on naval use of chaff. The U.S. Navy also used chaff during Operation Praying Mantis, so both occurances can be included, as well as any other examples we can bring up Masterblooregard 17:00, 1 October 2007 (UTC)[reply]

That sounds fine to me. However, I think the Falklands war deserves special mention because the sinking of HMS Sheffield by an Exocet is the event that caused both the UK and the US to embark on major programs to reduce the RCS of their ships so that chaff could be effective. The Exocet is particularly insensitive to chaff compared to other anti-ship missiles of the time. -

Amatulic 17:44, 1 October 2007 (UTC)[reply

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Using chaff in bad weather?

Can the distribution of chaff help discharge lightning in certain particular directions, as in lightning storms? 216.99.201.91 (talk) 03:12, 30 October 2009 (UTC)[reply]

Can chaff be used to control or dissipate inclement weather? Dexter Nextnumber (talk) 07:51, 1 November 2009 (UTC)[reply]

I've heard from older folks that they've used chaff they found as wrappers for sweeties at Christmas (as there was great shortage of everything in the late years of war). (The story's from Hungary, where we hang wrapped sweets on the Christmas tree, but probably similar in surrounding countries.) Would be nice if anyone knows a book that mentions this story. Hoemaco (talk) 09:35, 8 December 2009 (UTC)[reply]

Image of chaff on radar

There's a lovely image of the effect of chaff on a radar display, but the layperson, such as myself, may not know what a display like that "should" look like. Would it be possible to have a "before and after" style comparison? 203.217.150.69 (talk) 04:39, 3 March 2010 (UTC)[reply]

Good idea! Ryan4314 (talk) 23:44, 3 March 2010 (UTC)[reply]

While there's no before and after, I notice that since I wrote the above, someone has considerably clarified the caption - it now illustrates it very well. 203.217.150.68 (talk) 03:38, 16 February 2011 (UTC)[reply]

Would someone more familiar with the nuances of terminology please help distinguish the usage of the term "store" as applied to chaff on the store, versus the linked definitions, which are really a distinct usage? Thanks! 70.247.160.227 (talk) 01:37, 6 June 2010 (UTC)[reply]

'Store' was originally an RAF armourer's euphemism/general term for weapons that were carried by an aircraft that were intended to be dropped on an enemy, such as bombs, depth charges, etc. Nowadays, when these weapons are carried externally they are carried on stores pylons. —Preceding unsigned comment added by 86.112.84.42 (talk) 19:37, 30 December 2010 (UTC)[reply]

NEVER MIND. I found the reference for Fred Whipple's work and have added the US development of chaff to the Chaff (Countermeasure) article.

Chaff was co-invented in the US by Fred Whipple, then working for the Air Force, and Merwyn Bly, a Navy engineer. The reference for Fred Wipple's contribution (he calculated the lengths of the foil strips) used to be included in the Chaff (Countermeasure) entry, but is no longer there. Unfortunately, I am new user and if there is a way to see the older version, I have not discovered how. Initial experiments in the US were unsuccessful as the foils strips stuck together and fell as clumps. Bly solved this problem by developing a cassette such that when the strips were ejected they rubbed against the cassette, gaining an electrostatic charge. Since all the strips had a similar charge they repelled each other enabling the full countermeasure effect. After the war, Bly received the Civilian Distinguished Service Award for his work. See "Letter from Secretary of the Navy, James Forrestall to Merwyn Bly".

Both of these men made significant contributions to the US World War II effort and I would like to see them get credit. Although the letter from Forrestal provides reference for Bly's work, if anyone reading this has any information that would be useful for Fred Whipple's contribution (or can provide the relevant text from the earlier Chaff entry), please post it here.

Vince Bly (talk) 02:57, 1 December 2011 (UTC) Vince Bly (talk) 02:26, 2 January 2012 (UTC)[reply]

As it's such a 'primitive' technology - as in, I can tear up tin foil and throw it from a height to achieve the same effect - any information that could be found on whether chaff is routinely used in modern warfare/training, or of any refinements made to the technology since the Second World War would be a great addition to this article.

The presence of defence contractors selling chaff and reports from weather stations, often bemoaning the similarity of the radar signature to rainclouds supports its continued use and testing across the US, but also suggest a lack of novel designs. I suppose that shouldn't be surprising—for resonance effects across

theorists would have one believe.

I'll have a look for records of significant disruption to civilian utilities (weather stations, airports) or environmental concerns (which should in truth be minimal) caused by the use of chaff. The physics is already explained reasonably well, but an image may be of use. Tomásdearg92 (talk) 03:08, 5 February 2014 (UTC)[reply]