'Window' (Radar Chaff): WWII's Secret Weapon

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Chaff, known variously as "Window", "Duppel," or "Giman-shi" during WWII, consists of small strips of metal foil deployed from aircraft to blind and confuse enemy radar. It proved devastatingly effective against German air defenses during the war and is still carried by military aircraft to this day.

[@chrisfox3161]

The stowing of chaff behind speed brakes was not a new idea in the 1982 Falklands confict. It was a common practice on English Electric Lightnings at least 5 years before that. You tore the side of the boxes open and put them inside the air brake cavity. I did that in 1976.

[@markxfarmer6830]

F-15 drivers have long done this as well.

[@denmikseb]

I placed many flat packs of chaff in the speed brakes of F4 Phantoms during the Vietnam war. During run up, the pilot would close the speed brakes, holding the chaff in place. When approaching the target the pilot would open the speed brakes momentarily, allowing wind flow to dislodge the chaff into the airstream.

[@johngrantham8024]

The magnetron on Lancaster bombers was under the wireless operators seat and it was his responsibility to arm the explosive destruction charge before abandoning the aircraft. My late father was such a wireless operator and never felt entirely comfortable with the idea of sitting on explosives which, he wondered might go off accidentally or if hit by a bullet or a piece of flak.

[@ericadams3428]

The Germans recovered an intact H2s set a week after introduction due to the self destruction charge not working.

[@neilfurby555]

The real talent displayed here is making entertaining content about what are often complex and potentially baffling scientific and technical topics. I wish this channel had been available to me in my youth, it would have made learning a pleasure, rather than so often a chore to be suffered!

[@markwybierala4936]

Modern aircraft employ automatic chaff ejectors that eject packets of chaff when certain radars are detected by onboard programmable warning/detection systems. These packets are about the size of a bar of soap and contain a small explosive device to disperse the metalized strips or slivers. The number of packets and the rate that the packets are ejected is preprogrammed and set to whatever is determined to be the most effective again the known threat which is typically the guidance radar of an air to air missile. Navy ships also have the ability to shoot chaff into the air to a distance away from the vessel.

[@michaelhoracek9762]

Towards the end of the war my Czech grandfather was in a forced-labour camp in the Harz Mountains. The were working each day in the snow with inadequate clothing and calories, building accommodations for V2 techs. The Chaff which fell on their camp was collected to decorate Christmas trees. Some thought it was a Christmas present from the Allies.

[@tacomas9602]

"Some thought it was tinsel, a christmas present from the allies" Holy crap man. The innocence in war at times...

[@Shinzon23]

More people died building those than actually were killed by them when fired...

[@timdavies5219]

If you want to know about this WW2 air warfare tech, and how the Brits sussed out what the Germans were up to and how they attempted to counter it, read 'Most Secret War' by Dr R.V. Jones, the guy then at the heart of air intelligence. It's a brilliant book.

[@flvnow]

Also The Radar War - Germanies pioneering achievement 1904-1945, foreword by Prof RV. Also check out French RADAR, they were in there early too. Actually refined the magnetron, smuggled it to England to keep it out of German hands. Yes a Brit is credited with this refinement because the French didn't want their people being forced into revealing the details.

[@richardvernon317]

@@flvnow Lots of people came up with various type of multi cavity Magnetrons. The big issue with all of them was frequency instability, low power output, poor efficiency, hard to cool and short running life for the short wavelengths. They were quite useable with wavelengths of 50CM, but when taken down to 10CM, all of the issues I just mentioned seriously affected their operation. The Germans never though about building a device with a metal body and their design was rejected due to the issues above. The Russians and Japanese did use a solid anode block, but the UK were not aware of it because they were never patented it before the war. The French magnetron was no better than any of the other ones, bar the fact it used a oxide coated Cathode. That part was integrated into the British GEC device based on Randell and Boot's design. On top of that the British were the only nation to come up with a way of dealing with the Frequency stability issue by strapping the Anode cavities and the British also worked out that as soon as the thing was working, you didn't need to heat the Cathode. As for the development of Radar in the UK and Germany, there was a major difference in how the two nations ran their programs. In Germany, The Signals Research Establishments came up with the basic concepts, these were given to Industry (normally a single compony) to develop and the two services refuse to share information or allow their companies to share technology. Plus the companies fight over things like Patient infringement. The driving force for development is industry and they have to build high spec stuff to sell to the Military. British on the other hand, Military experimental establishments running the show, Military fully on board with Radar. Industry cut out until WW2 starts for security. Ideas and tech shared between all three services and they are happy to get anything into service as quickly as possible. Lash up kits built out of off the shelf equipment common and in service within months. First Allied "Real" Radars that turn and burn in service in 1941 (AMES Type 8 and CHL Mk 5). German First's are mainly start of Development, while British Firsts are operational equipment in service. Take for example PPI display system, Germans do think of it first (1936), Don't build a display until 1939. Show it to Goering in 1939 and he fails to order it. Radar for it not started until 1941 and not finished until March 1942. Germans then have to develop new phosphor to allow tracks to be seen which delay entry into service of their PPI radar until 1943. British think of the idea in 1938. CH and RDF2 (Airbourne radar) has priority. CHL then built to deal with most of the gaps in CH cover. CHL when designed more advanced than Freya of same period (used spilt lobe receiver). PPI display system development started in 1939. phosphor issue dealt with first. Prototype display built in May 1940, fitted to prototype radar in June 1940 Issues with Display system fixed by November 1940. 6 emergency deployment systems built in December 1940 - January 1941 and all deployed by the end of that month. AI Mk 4 and Beaufighter also becoming operational in early 1941 and by March 1941 the RAF are killing German Bombers in the way radar controlled intercept is done today.

[@fredblonder7850]

A side note: You may wish to look at Project West Ford ( en.wikipedia.org/wiki/Project_West_Ford ) which put chaff into Earth orbit as a communication device. This was the era of the Echo communication satellites, before the active communication satellite was developed.

[@CanadianMacGyver]

Yes, I was considering covering that, but several other channels have already covered it, including the other one I write for, Today I Found Out. I might, however, do a broader overview of space-based telecommunications technology (Echo 1, Telstar etc.)

[@RWBHere]

Please do that. @@CanadianMacGyver

[@HouseholdDog]

My mum remembers this tinsel falling from the sky during the war. The whole field was covered in it.

[@jeffreyyoung4104]

There are many stories about chaff, one of them was due to the waste material being very small and colorful, that they sold it as a child craft material that soon became glitter! And one company that still makes glitter, is now a top secret manufacturer of chaff. Another story was about tinsel for Christmas trees, And it took the ability to aluminize plastic to get the chaff/tinsel to be strong enough to work for both jobs! All it takes is a google of 'secret glitter' and you get many stories about the strange uses of glitter!

[@JamesLaserpimpWalsh]

I was going to say that looked just like the radar that commando raid was sent to capture in France. Nice. Cheers for the vid.

[@rogerdildeau7507]

Your videos are very interesting and informative. Please keep them coming!

[@WildBillCox13]

Most interesting. Also, you were pleased that you'd earned almost 2000 subscribers when you posted this two years ago. You've got 52.1 K viewers as of this comment (11Nov2023). Good on you.

[@doddsy2978]

We used chaff in jiffy bags under Phantom airbrakes back when the Phantom and Lightning provided the backbone of British Air Defence.

[@dorcusmallorcus6450]

Love that research. Great detail, good to get the insights. Thank you.

[@allangibson8494]

The magnetron also permitted the fitting of radar to submarine periscopes - so giving submarines warning of aircraft in the area prior to surfacing or while snorkeling…

[@Srinathji_Das]

Wow! Thanks for sharing this interesting history!

[@bearcatracing007]

This was fantastic, thanks

[@tomobedlam297]

Fascinating subject. Well done!👍

[@davebeedon3424]

Fascinating video. Thanks for your research and presentation.

[@tomwarger7209]

Superb channel! This is great information on things nobody else presents.

[@rpkamins]

Awesome channel! Keep up the great work 👍

[@mandolinic]

This is one best and most informative channels on KZbin. You deserve far more than 50K subscribers.

[@piccalillipit9211]

Well he has 81.5K now so your comment worked...!!!

[@johnberger55]

@@piccalillipit9211 91.6K now

[@rabaohong9492]

I am a subscriber this is a great series, very informative, very clear and easy to understand. Best of success to you and this channel👍

[@Allan_aka_RocKITEman]

Great video, Gilles...👍

[@Steve-GM0HUU]

👍Excellent video, thank you.

[@napster7825]

Congratulations on the subscriptions. I enjoy your channel.

[@Sacto1654]

A reason why _Window_ worked so well was that German radars at the time operated in the same radio frequency range as the old UHF television channels in the USA, which made them quite susceptible to interference. _Window_ didn't quite work for the LIchtenstein SN-2 radar because it operated at a much lower frequency of around 90 MHz, and it was only from later in 1944 that they had a new type of _Window_ specifically to counter SN-2. Had the Germans figured out the cavity magnetron by 1942, they could have fielded radar operating in the 3 to 5 GHz range like the FuG 240 _Berlin N_ unit , which was just about impossible to jam given the technology of chaff at the time.

[@Inkling777]

I've worked on anti-aircraft radars being tested against chaff. Doppler radar isn't necessary. For incoming or outgoing aircraft the difference between the aircraft and the chaff is easily spotted since the latter trails behind aircraft, blooming up on a A-scope (range) as it spreads out. Of course, the resulting clutter still makes it hard to track the aircraft.

[@Slavicplayer251]

promenade is such a beautiful piece

[@OpenCarryUSMC]

Loaded buckets and buckets of chaff on F4’s and F18’s. Tubes of aluminum threads that were super fine and ejected from a bucket full of tubes with each tube fired in succession by a small squib. Early 80’s through 1999

[@sheilaolfieway1885]

If the germans did not have radar how was the Dehavalin Mosquito a 'stealth' plane? thank you for the history of chaff and it's use.

[@elddisguy]

Most of the Mosquito was wood, a non radar reflective strtucture. The only metal parts were the engines and various small metallin linkaages associated with the control surfaces and some of the instruments.

[@howardchambers9679]

​​@@elddisguyI think she was referring to the myth that Germany didn't have Radar. Because obviously if they don't have it, the word "stealth" attributed to an aircraft would be pointless.

[@howardchambers9679]

Dehavilland btw

[@kristianhartlevjohansen3541]

@@elddisguymetal propellers - quite the signature!

[@richardvernon317]

@@kristianhartlevjohansen3541 Germans did have issues picking up the Mosquito, It is covered in a meeting between Goering , Milch and Kammhuber in March 1943, most likely after 109 and 105 pathfinder squadrons started trashing Krupps of Essen with Oboe!!!

[@occamraiser]

Both the allies and Germans had chaff, but neither used it for fear of the others learning about it, for quite a long time.

[@Ian-mj4pt]

Neither used it ? It wax used if im not mistaken

[@studuerson2548]

I remember chaff covering our schoolyard in the late 50s. 10 miles north of Milwaukee.

[@staninjapan07]

Good one! And with 57,600 subscribers as of November 2023, I hope it's going well for you.

[@snarkymatt585]

Is it just me or is this channel like a cross between Reviewbrah, The History Guy and Forgotten Weapons?

[@thetimebinder]

I'm all for it!

[@cabletie69]

"Cabinet of Curiosities " is that a Pratchett inspiration?

[@tomarmadiyer2698]

This idea floated around for a little bit...

[@behindthespotlight7983]

I’ve studied WW2 for 40 years. Both grandfathers served. One in the Pacific. The other in ETO. The compelling thing about WW2 is one can never learn it all. In fact a dedicated student of the conflagration can barely scrape numerous surfaces in a lifetime. Victor Davis Hansen published a book two years ago where he posits the following (and l agree.) In both World Wars the Germans knew that they must win fast victories because they lacked the industrial capacity, the fighting population and the economy to sustain wars of long strategies and/or attrition. Perhaps the reason Stalingrad is often noted as the fulcrum for who would claim ultimate victory is not so much because the Axis lost Sixth Army? Perhaps Stalingrad happened to occur at the midpoint when it became obvious that Germany would run out of fuel, men and money before the Allies? As a side note all bullies worldwide should take note of the Pervatin fueled German mindset that led to nation ending mistakes in 1940. Just because you can overrun small unprepared countries and countries with whom you break diplomatic agreements does by no means indicate that you are ready to take on the largest navy in the world (Great Britain) the largest industrial giant (America) and the largest population (USSR). Hindsight being 20/20 (and setting aside the New World Order/international banker conspirealities) Nazi Germany never stood a chance.

[@Joe-lb8qn]

I recall my father telling me about finding chaff on the ground when he was on the continent in maybe 44 or 45. I dont think they knew what it was for but i may be mistaken.

[@camackerman3929]

so the glitter shortage is chaff...

[@fredyellowsnow7492]

There's a lot in that I didn't know about German radar.

[@rocketscienceinstituteinc8993]

From c 1949-1953 B-36 bombers flew over central California, very very high in altitude. In that same period, 4-cm long thin aluminum strips were found here and there across the farmland. We soon learned the aluminum was "chaff" and associated it with the B-36 bombers flying high overhead around the same time. Six turning and four burning over 50,000-ft, spewing chaff? They were carrying the earliest models of hydrogen bombs, that's a fact.

[@kimvibk9242]

The wife of Odin is called Frigg (or Frigga). Freya is the goddess of female fertility (and libido), supplemented by her brother Frey who was the masculine counterpart. Also, the German for giant is Riesen. The word Reise means travel.

[@Elephantine999]

That was interesting. The 22-meter(!) British radars seem comical now.

[@jp-um2fr]

Sorry about the last one but they really do ask for it. I do love you videos. I'm not sure if it's OK for me to download your videos but 'thod it', It's just for me. If Chaff ever deserved KISS (keep it simple stupid) I can't think of a better one. A little add on. W.A.A.F. (Women's Auxiliary Air Force ) Those young girls had the job of shepherding damaged planes home over the radio. Sometimes they heard the last agonising cries of the pilots. Not one left her post but afterwards .......

[@marcusmoonstein242]

There's something funny about the English and the Germans both knowing about chaff, each thinking the other side didn't know about it, and therefore not using it themselves because they didn't want the other side to have such a valuable weapon.

[@Clapperofcheeks5000]

The British. Irish welsh and scottish are not English

[@jackgamer6307]

I'm surprised you didn't mention US made HE-VT anti-aircraft shells when talking about the magnetron

[@richardvernon317]

The two Devices were not related!!!!

[@wrs10]

"In 1943 most German bombers were facing the Soviets in the east" Er, no, even before the time of the US formally was at war with Germany half of German bombers were facing British forces either in the west or in the Mediterranean as Britain had been so successful in cutting off supplies to North Africa Germany had to switch resources in an effort to re-establish supplies. By the time of the Allied invasion of Sicily in July 1943 Germany just did not have bombers to be much of a threat.

[@Imbel.40]

1:50 You know Roberto Landell de Moura?

[@cjmatulka8321]

Ah, thanks for the presentation. Being a child of the late 50's and very familiar with the discreet nature of the topic and some of the materials gathered from the yard I can say with a good degree of confidence that you have missed a lot of the different types of the different confetti that we found as children. The big scare was the possibility of being radio active or otherwise contaminated. Needless to say I was able to sample most of the training and prototype stock you've mentioned plus the small 3/8" double sided squares. Maybe these were for immitation of clouds for aircraft to hide in? We never saw any of the aircraft making a drop so we thought it was at a very high altitude, the other spaghettis I witnessed drops and thought it a beautiful site. Or... rainmaking/cloud seeding experiment also going on at that time?

[@cjmatulka8321]

P.S. The chaffed area was often followed by low level supersonic fighters making their runs. At a half mile away the whole farm would shake let alone rattle the windows, epic stuff for the times as kids.

[@WarblesOnALot]

@@cjmatulka8321 G'day, Not in The SECOND Great Patriotic Waaauughhh(!) To End ALL WAR... Everything which You SAID..., Was WRONG... Go back & Open a HISTORY. Book. Just(ifiably ?) sayin'... Such is life, Stay safe. ;-p Ciao !

[@PWARHOLM]

"Unfortunately" = "Unfortunately for the Axis war effort" 🙂Pretty fortunate for us. ;-)

[@aviphysics]

"unfortunately" ??? In regards to German war failures, I would say "fortunately"

[@BrazzaB1]

Is it window or winnow?

[@MajinOthinus]

Actually, the German countermeasures were ready and applied within a month of Window's first use.

[@RWBHere]

And Windows still crashes, eight decades later! 😉

[@jp-um2fr]

We gave the Americans the cavity magnetron and penicillin as firstly a good will gesture and we just could not make enough penicillin. I believe they gave us the baseball cap and chewing gum in return.

[@G7VFY]

Speaking of radar in movies, you HAVE to watch this TERRIBLE film, Radar Secret Service (1950) Action, Crime, Drama as the makers clearly have no clue what radar is. So bad it will make you CRINGE!!

[@G7VFY]

Film is on youtube kzbin.info/www/bejne/mJbZiGeXgpyihNE

[@John-pp2jr]

👍true description.

[@railgap]

Want some fun? Open a modern (crimped mylar) packet in your room!

[@NGabunchanumbers]

A lot of the time you say 'unfortunately' in ways that sound funny, like "unfortunately the germans did not manage to win the war with this weapon...." Or something like that.

[@MartinFrancisEcclesiact]

I noticed that as well actually. Perhaps if you said it's an equal number of times for British setbacks as for Germans ones, it would sound less biased. But i'm sure it was unintentional.

[@daddymcguire1181]

Glitter brought me here..

[@Khorne_of_the_Hill]

How am I not surprised that the Germans were way ahead lol The British just love the mythology of them inventing everything ever in a shed behind a residential home 😂

[@andycraig7734]

Thank you for typing those fine English words. I'm viewing them on a tablet running the British invented ARM CPU.

[@charlesg5085]

He got alot of those techincal detail incorrect.

[@KarlBunker]

* a lot * details You got a lot of your words incorrect. And unlike you, I'm providing examples to support my claim.

[@charlesg5085]

@KarlBunker Auto correct errors in my case. I had another language selected, so it kind of goes nuts. I speak so many languages that it autoswitches back and forth.

[@KarlBunker]

@@charlesg5085 As they say in Australia, yeah nah.

[@charlesg5085]

@KarlBunker I have heard that, but mainly from the homeless grifters I encounter there.

[@TouYubeTom]

unfortunately the luftwaffe wasnt what it was before? you disappointed?

[@SeniorChief604]

Dear Gills, Why do you trim your beard so unevenly? The right side is higher than the left.

[@ravener96]

I assume by accident, its not something i noticed

[@budgiefriend]

Thanks mate, now i can't take my eyes off of his beard.

[@bigbob1699]

You might work on your body language.

[@ymishaus2266]

Would love to hear some of your suggestions, coach.

[@bigbob1699]

You might want to move around what you are displaying and work with a young helper. Anything to make you less stiff. Keep the voice and precision.

[@steveread4021]

I don't care for the way that you repeatedly say unfortunately when referring to a nazi win.