Mosquito Resin or IR Lights

[bobgpw]

Edgar

I believe that resin lamps were just very low wattage for formation flying. The only IR equipment that I can think of on Lancasters, for example, is the "Z" equipment in the nose. This was only designed to function with the IR interrogator of an AGLT equipped Lancaster. I don't know of any IR equipment being in regular use with the RAF during WW2 - the Germans had IR binoculars and "Spanner" on some nightfighters. The man to ask about Mossie nightfighters is Tony Agar at the Yorkshire Air Museum - he owns HJ711.

Always willing to be corrected!

Bob

[bobgpw]

Edgar

I have no intention to howl you down, but the lights on the trailing edges of Lancasters and Halifaxes operate in the vsual spectrum. IR lights would not be visible to the naked human eye, and yet these same "invisible" lights were used by crews for formation keeping prior to crossing the enemy coast. After that time, all lights were extinguished.

[i]Precisely what the pilots were told; the alternative would be "Keep them on, since they're a defence against our own nightfighters." Not exactly the way to keep it secure; one POW pilot overheard complaining that the lights hadn't stopped him from being shot down, and the Germans would have been onto it in a flash. [/i]

Bear in mind the number of bombers crashing in German held territory and it would not have taken the Germans long to work out that the lamps were "IR" - in the same way that they had rebuilt H2S sets from crashed Stirlings and then used the information to develop Naxos homing equipment.

Strange projections on the t/e of early Halifaxes would be the fuel jettison pipes - these were later deleted in an attempt to clean up the Hally and improve performance. I'm not aware of any similar projections on Lancs or Stirlings. The Wellington also had fixed fuel jettison pipes.

As for being a defence against our own night fighters, from what I understand, most Mossie and Beaufighter crews did not like operating near the bomber stream as gunners had a habit of firing at anything with two engines. It would appear that most Intruder crews operated near to night fighter assembly beacons or in the vicinity of n/f airfields. Over the UK, the anticipated inbound route of the bomber stream was known to the air defence network. This coupled with use of IFF meant that losses to friendly fire were kept to a minimum.

On the Halifax, Stirling, Manchester and Lancaster, the "trailing edge formation light" was a design feature from day one (circa 1936-37). This was before anyone could have forseen the use of IR interrogators by night fighters!

Regards

Bob

[andym]

Positively my last posting on this one; I spoke to Peter Cooke, tonight, since the information came from him, and this is how he got it. When he was researching for his 1/24 Mosquito project, he heard a reference to "resin" lamps, but couldn't find any thing more, so he wrote an appeal (in Aeroplane Monthly, I believe,) and got two replies. One, from a pilot, said that they were formation lights, and they were told to keep them on at all times, using them to follow each other into the bombing run. "But," he said "They were absolutely useless, so dim we couldn't see them properly."

Then he had another, from a man who said that he worked at the factory where the lamps were made, they were definitely IR, and "resin" was the wartime codeword for IR, so that they knew that any reference to resin concerned the IR system. The system was kept secret, right through the 1950s, in fact, he says, some jets flew with them. Peter says that, if you look at the RAF Museum's reprint of the Mosquito manual, it's possible to trace the wiring, but no mention of the lights, themselves, can be found, neither do they appear in the pilot's notes.

When Peter started his research on the Lancaster, he found that there were three lights, at the t/e, and one of them was, also, "resin."

Edgar

As a side note the AP for the Mosquito MkII, NFXII, and NFXVII includes the wiring diagram for these 'Resin' lights (their quotation marks)as well as mentioning them in text and drawings as well as showing their position.

HTH

Andy

[bobgpw]

Edgar

I appreciate that you do not wish to engage in the debate, but your evidence tends to contradict the arguments that you make.

IR light is not visible to the human eye. Therefore, the "dim" lamps that your pilots are allegedly struggling to see as they are too dim - would actually be invisible.

Now, here is the argument again. The IR lights were secret, so pilots were told that the very dim lamps on the wingtips, were formation lights. They must have thought it very strange when the lights that they selected "ON" didn't appear. Time to have a chat with Chiefy - and guess what - everyone else in the squadron has got the same problem.......And off they went, flying into the night, following these "dim" lamps - which they would not actually be able to see!

And now the bloke in the factory who knows that the codeword for IR was "resin". I doubt it. Resin appears to have been used to describe anything made of Bakelite or Polystyrene. Here are a couple of items from t'interweb: www.powerhousemuseum.com

Description:

Aircraft indicator lamp with cover, polystyrene synthetic resin / metal, made by Commonwealth Moulding Pty Ltd, Arncliffe, New South Wales, Australia, 1938-1942.

Indicator lamp for aircraft fitted with injection moulded lamp cover made from polystyrene synthetic resin; Black cylindrical base with 2 [copper] 'prongs' fitted to bottom; screw-on collar around top which forms coverig for clear plastic light cover.

The original object label for these aircraft indicator lamps states: 'Transparent and red covers are moulded from polystyrene synthetic resin'

I think I'm pretty certain as to the nature of resin lamps.

Bob

[Mike]

Not that I profess to have any great knowledge of Mosquitos (just great affection), but every IR bulb that I've seen emits a faint glow in the visible spectrum, which in another hobby of mine makes people with 1st gen active Night Vision Goggles (NVG), which use a small IR lamp to illuminate the view, visible to the naked eye as a faint orangy red glow in the dark. It's only passive NVGs that don't have this, relying on amplification of existing light, rather than shining "invisible" IR on the scene.

Therefore, a "formation" light that emitted a faint glow and is purported to be an IR light by such knowledgable folk as Edgar works for me.

Might I also add that I'm disappointed to see personal digs creeping into the discussion. By all means disagree, but do it politely, as us Mods tend to take a dim view of name calling.

[bobgpw]

Edgar

I never said you lied.

I merely pointed out that you were wrong to assert that IR light sources are visible to the naked eye. They are not. Period. Fact. If you disagree, go and argue with Mother Nature and NASA. My point is that your pilot source could not see IR LIGHT - no one can. Unless he had been eating lots of carrots or had altered the laws of physics. Maybe you know better.

Your pilot could see the lights - BECAUSE THEY WERE STANDARD VISUAL SPECTRUM LIGHTS NOT IR.

As for the E2B, why would the lighting unit be IR? The E2B uses 28 volt red light. It is NVG compatible at 6volt. Ask me how I know this - go and have a look see what I do for a living. It involves aeroplanes. As for you seeing a glimmer of IR light from the compass - again, go and get checked out by the GP. You must be the only man on the planet that can.

The items I chose to illustrate my point came from Australia. They are, I believe, and it is just my belief, representative of aircraft technology of the period. As for their relevance, well during WW2 Australia was on the Allied side. Again, I too have first hand experience of working on vintage aircraft. The lights in the museum examples look very similar to those I have encountered.

The earth is flat Edgar, and the Sun revolves around us.

Bob

[bobgpw]

Edgar

The red mist seems to be coming from your direction. I am not accusing you or the pilot or the factory manager of lying. Why would I, they have merely passed on that which they believe to be true. It doesn't mean that they were correct though, does it?

But, the fact is that IR light is not visible to the human eye.

As to your experience in the aviation instrument industry, I will readily admit that you will know far more about this subject than me. However, I am currently in the aviation industry (air traffic controller - for what it is worth) and have been for 12 years. The experience that I have and that of my colleagues and friends is also of relevance.

As for a closed mind - well in my job, that can be a little dangerous. I never said "I know" all about this - I merely stated that the information that I have read and seen does not - in my opinion - support the assertion that the formation lights were IR.

Edgar, I didn't come to the forum to upset you or anyone else and if I did then I apologise. My comment regarding your eyesight was intended to be lighthearted, but the medium of the internet does not allow for you to hear me speak and so it was lost in translation.

As you say, it is time to let this one go. I hope to enjoy more debate with you on other subjects in the coming years.

Once again, accept my apologies for any upset caused.

Regards

Bob

[Edgar]

Clean slate, as far as I'm concerned, sorry for the misunderstanding(s.)

Edgar

[AnonymousA667]

Bob, can I recommend using emoticons, especially if making jokes? It can make a difference between and

FWIW I've always understood that whilst IR is not in the visible spectrum, IR emitters may appear to be incandescent.

peebeep

[John Laidlaw]

FWIW I've always understood that whilst IR is not in the visible spectrum, IR emitters may appear to be incandescent.

Absolutely correct. If the source was a solid-state monochromatic source (e.g. an IR-emitting LED, or IRED), you wouldn't see a thing. But most emitters do so over a fairly broad bell-shaped curve, and there will be spillover into the visible part of the EM spectrum from near-IR sources.

[Edgar]

Found this (on a B.35, and an ex-Israeli FB VI) at the Mosquito Museum. It now looks, to me, that there were standard bulbs fitted (makes sense if it was to be kept secret,) and the light went through a filter. Oh, yes, and both lights were red; not a green, or white, to be seen anywhere.

Edgar

Edited March 23, 2009 by Edgar

[Troffa]

Hi Edgar,

thanks for posting the pictures.

I have more than a passing interest in the Strategic bombing campaign of WWII and the technologies employed by either side in that battle. I find it fascinating that a system of IR identification could have been in widespread use by the British and yet is not widely recognised all these years later.

I have several books on the subject and I can find no reference to IR lamps, resin or otherwise in any of my references, most notably "Most secret war" by RV Jones.

RV Jones was intimately involved in the theory and development of various British Infra-Red technologies and would have been involved in any IR detection system employed by the RAF.

Jones developed an IR detector as a possible alternative to RDF (RADAR) and flew in an aircraft equipped with a IR detector of his own design in an aircraft from Farnborough in 1937.

On April 27 1937 he successfully detected another aircraft in flight by solely Infra-red means and continued to develop this technology over the coming months.

The detector demonstrated its ability to detect target aircraft purely by the IR energy generated aerodynamic heating of the wings and fuselage, even when countermeasures such as shrouded engine exhausts were employed. Eventually this technology was shelved as the British developed successive Airborne Intercept radars, which had the advantage of not only giving a targets bearing but its range as well.

The book mentions several British and German projects of the period and describes in great detail several detection and identification systems employed in both the Radio and IR spectrum's and at no point does he mention any system that was routinely employed that would require the use of the IR lamps on the trailing edges of British aircraft.

Long after the war has given up its darkest secrets (Bletchley Park etc.) I believe that we would have a broader knowledge of such systems if they existed. (I am off course willing to be proved wrong and wait for the day when some documentation can be found that describes this system and its operation!)

I have a cutaway view of a Mosquito that does identify the lights on the trailing edge as Resin lamps, and have even found a reference on the web to the "resin lamp" switch in the cockpit of a Hawker Tempest (not a noted night-fighter!) (Fig 3, Item 30 in this link: http://www.hawkertempest.se/Cockpit.htm so I have no doubt that this is in fact what they were referred to as, but I am not convinced that these lights are Infra-Red for the following reasons:

I find no evidence that the British routinely employed a detector for such lamps.

That the lamps would not be required if a system flew in 1937 that could detect aerodynamic heating of an airframe.

That the Germans would have quickly deduced the nature and purpose of such lights and have developed countermeasures/ exploited them. (And that this exchange would be known to historians)

I hope that you recognise my genuine attempt at civil debate and wish you well in your search for the definitive answer, I suppose what we ought to do is get a lamp and stick 24 V DC across it and see what it does!

Cheers,

Troffa.

(Edited to correct faulty link)

Edited March 24, 2009 by Troffa

[Edgar]

Actually, one of the first uses for a Tempest was at night, by the FRDU, against the V1, and the likelihood of being mistaken for a Fw190 must have increased dramatically at night, I suspect. Unfortunately, I get "File not found," on that Tempest reference, but I'll see if I can find something in my files.

I'm coming round, more and more, to the idea that it was the housing which produced the IR, probably via a filter, with a standard bulb behind it. To a technician "lamp" = bulb; to a layman (me) it's the fitting. If the Germans did hear reference to resin lamps, and looked only at the bulbs, what would they have seen? From what Peter was told, it was a form of IFF, not detection, with the lights showing up "like Christmas trees" (as it was described to him) when interrogated, otherwise "dim as a Toc H lamp." In "Confounding the Reich" there's mention of "Primrose," which, previously, I'd never heard of, and appears to be a form of interrogation; now that the Mosquito Museum's open again, maybe I'll be able to find more. Certainly, the voluntary staff, at the museum, have no idea of the purpose of the lights (and both, on the B.35, have a red insert.)

I have no problem with debate, Troffa, if it's constructive; disbelief isn't research.

Edgar

[Jazzy Jase]

Unfortunately, I get "File not found," on that Tempest reference

The link is incorrect. There is a bracket at the end that needs to be removed.

Try this: http://www.hawkertempest.se/Cockpit.htm

Edited March 24, 2009 by Jazzy Jase

[Troffa]

Hi Edgar,

I have just checked that link and I am getting the error message as well,

try cutting and pasting the link into your browswer or try going to www.hawkertempest.se and having a look under the "In detail" section for "Mark II in detail" . The cockpit diagram for the tempest II shows the switch on the right hand side console of the aircraft, the Resin Lamp switch is the middle one of a bank of three.

The switch is also annotated on the Arthur Bentley drawings on the same site under "in detail" and "Drawings", the switch is marked as item 70 in this case.

sorry for the cumbersome directions, I have no idea why I cant link direct.- I cannot however find any evidence of a light of any description on the trailing edge of any part of the Tempests I have pictures of! I hope you have better luck.

I have a couple of observations for you-

1. Terminology: RAF aircraft electricians of my day referred to what we would call a "bulb" as a "filament"- "Bulbs grow under the ground, laddie", followed by a cuff round the ear seems to have been the order of the day during training for my green bretheren.

The term "lamp" would normally refer to the whole assembly, i.e the filament and any reflectors, housings, guards and lenses etc.

2. Operation: If the Resin lamp was an active source of IR light then one would only require an infra-red detector or sight to pick up the radiated energy from the Resin Lamp, The IR light being invisible to all but those so equipped.

If the Resin Lamp was designed to react to some form of interrogation by a suitably equipped system then one would really only require the resin lamp to be a reflector to any IR energy directed towards it, or the interrogated aircraft would require a more complex system than is being suggested existed by having the Resin Lamp react in a specific way when "interrogated" by a friendly aircraft- this would obviously require some form of processing to take place and would leave a larger footprint on wiring diagrams , blue prints etc. than is currently apparent.

I am genuinley intrigued by this whole subject and will do some further digging of my own, good luck in your research and please feel free to pm me if you would like to continue this offline.

Regards,

Mark

[Edgar]

Thanks for that. Interesting that it's for the Tempest II, and has the post-war harness illustrated; it partially confirms my suspicion that the lamps stayed in use, post-war, maybe even including Suez(there are, for instance, some familiar-looking "lumps" on Brigand and Wyvern wings.) With closure time, for the National Archive's files, normally set at 30 years minimum, it might go some way to explaining the long delay in the information's appearance, after all, we knew nothing about Bletchley Park, until very recently.

Incidentally, I was not having a dig at anyone, in particular, with my remark about debate; rather it's a growing irritation at the readiness (even in some normally respected magazines) of some authors to ditch information just because it's old, or not written in official orders.

Edgar

[Dr Lurrrrve]

There is reference to IR identification lamps being used on 100 Group Fortresses. These were located in the glazed nose section. The brilliant book "Confound and Destroy" records this information.

[Troffa]

There is reference to IR identification lamps being used on 100 Group Fortresses. These were located in the glazed nose section. The brilliant book "Confound and Destroy" records this information.

Cheers for that Doc, I will have to expand my Library. Amazon here I come!

[bobgpw]

Oooohh I just couldn't resist this one again.

Troffa - I think you hit the nail on the head. To create a response from an IR lamp would require:

1. An interrogator signal. Another IR source or electronic signal?

2. A processing unit to switch on the lamps.

3. A receiver processing unit and aerial array.

As "Resin Lamps" appear on the major British bombers from the start of WW2, then this IR interrogator must have also been in use then or in development? A copy of "Radar: A Wartime Miracle" would lead me to believe that the Ministry of Funny Ideas and Gadgets was far more interested in RDF/Radar.

Edgar, find any of these in the RAF museum archives, National Archives etc. and I will be the first to buy you a pint!

As a relatively hi-tech solution, this would also require RAF personnel who could install and repair the system. The "Z" equipment used in the noses of Lancs is well known. That it may have also been used in the nose of 100 Group Forts as they plied their trade in the bomber stream is also highly likely. Why is it in the nose? Well the AGLT turret, fitted with a passive IR interrogator, i.e., the system is constantly operating, and visible only to suitably equipped aircraft, is located at the rear of the Lanc.

The term resin lamp was used prior to WW2, and as I have shown with previous posts, I believe that it was used to describe plastic lamp units.

Sits back and awaits IR response.

Bob.

[Troffa]

For any interested parties there is a thread in the "Aviation history and Nostalgia" forum on www.pprune.org on this very subject. Nothing conclusive so far, although the two ex bomber command aircrew who have contributed have no recollection of Resin Lamps, IR or otherwise. I can also thoroughly recommend the thread in the Military Aircrew forum on the same site regarding "gaining a RAF pilots brevet in WW2" Regle and Cliffnemo's accounts make for excellent reading. You may have to register to log on but I recommend Pprune to one and all interested in Aviation.

As for Resin Lamps some primary research is probably required, don't suppose anyone has a topic 10 for a Lanc or Mossie do they?

cheers,

Troffa

(still in the dark!)

[Edgar]

So, to recap. Peter Cooke receives information, from an unreliable source, that "resin lamps" = infra-red technology. Couldn't happen because infra-red is invisible.

Some of us have experience of infra-red lights giving off a small amount of light, but can be ignored.

I find, and photograph, odd electrical fittings (both red) on Mosquito wings, freely admitting that I don't know their purpose (and neither did the staff at London Colney,) but they can be ignored.

Now I'm told that it couldn't have happened, because all of the resources were concentrating on radar, leaving no interest in IR. Well, in the "AIR" section of the National Archive, there are 30 files on IR, from 1940-50 (I deliberately kept the enquiry restricted to those dates,) some dated as early as 1940, or 1941. Using the same parameters, in the "AVIA" section there are 71 files, three of which, dating from 1941 - 1945, have the title "Identification and Recognition (code 5/5); Air-to-air recognition of friendly bomber aircraft by infra-red system; trials." Another, 1941-1943, is "Identification and Recognition(code 5/5) Infra-red aircraft detector." There are others, with equally intriguing titles, but, since there was no interest in IR, we can safely ignore them, too.

So, there is a total of 101 files on a subject in which there was no interest, so there's no need for me to investigate any of them; just as well, since I have 273 Spitfire, 15 Seafire, 137 Typhoon, 73 Tempest, 90 Mustang, and 586 Mosquito files to check on, first.

Edgar

Edited March 29, 2009 by Edgar

[Robert A]

Troffa & Edgar,

I have come to the conclusion, from my own research, that an IR system was used, certainly from '44 onwards by Bomber Command. I've had more than a passing interest in the activities of 100 Group over the last few years and have spoken with veterans of both the ground and aircrews and they have confirmed that IR identification systems were in use.

There is evidence that Mosquito NF30's of the Group were fitted with an IR telescope on the centre of the cockpit coaming above the instrument panel. I'm still trying to find out if they were also fitted to the other intruders from the group. One veteran I spoke with remembers that they used these as a fail safe for identifying their target to ensure no friendlies were shot down by mistake. I did ask about the fitment of IR lights to the Mossie but he couldn't say.

Speaking to a number of B24 crews from 223 Squadron and they confirm having a pair of IR lights fitted below the rear turret and a pair fitted in the front to show through the bomb aimers glazing on the nose as this was redundant in their aircraft.

One gentleman said that they were set to flash a specific morse letter, which changed with each mission.

Well that's my two pence worth, hope it's of some use.

Bob

P.S. Troffa if you contact me off board I may have a copy of "Confound & Destroy" thats looking for a new home.

[bobgpw]

Edgar

Are you getting thirsty yet? Your pint is still in the keg.

Resin lights mentioned prior to WW2. Find me a proven IR detection system in use by the RAF in WW2 that would cause all of their front line bombers to be fitted with resin lights, IR of course.

I too have carried out a lot of research over the years and was fortunate to speak regularly with members of 4 and 6 Group aircrew and ground crew over a period of four years. We discussed all of the major navaids, technology tactics, etc. and not once did anyone mention IR detection systems.

IR bulbs may cause a glow (visual spectrum though, not IR - you can't see IR unless you are Lee Majors), but at what range is this visible to the naked eye? A few feet or several hundred yards?

All I said was that the AM seemed mighty interested in RADAR not IR. Witness the huge sums invested in it. Go figure.

P.S. The use of the IR telescope is documented.

Bob.

[bobgpw]

Oh,

Forgot to add, the US Navy used an IR communication system in the late stages of WW2. It consisted of an IR "hood" fitted to a lamp, which allowed ships to be operated in total darkness. No naked light. Read on.....

A ship in a formation may receive the signal, "Nancy Hanks" by TBS which meant, "Stand by for message by infrared signal light". The signal was sent by a 12" signal searchlight or 300W train lights equipped with infrared filters that made the signals invisible to the naked eye. It was received with a US/C-3 infrared telescope.

Infrared transmitting equipment generally consisted of incandescent lamps with infrared filters. The higher-powered shipboard equipment used glass filters (Corning 2540), which were rugged and eliminated all trace of visible light. The handheld lamps such as used on the snooperscope and sniperscope used a plastic (Polaroid XRX) filter.

I can't claim the credit for this research, but the website author appears to know quite a bit about IR telescopes as his grandfather helped develop them. He asserts that the earliest field use was in 1944, and this would mean that we Brits with our resin lamp equipped aircraft of 1938 onwards, knew that Uncle Sam would invent an IR telescope, small enough to be used in the cockpit of a Mossie by 1944. Genius. Incidentally, this work was so secret that a Patent wasn't applied for until 1946.

In the 1940's, Philo Farnsworth (USA) invented the infrared telescope during World War 2. Don't believe me, argue with Massachusetts Institute of Technology. The Luftwaffe fielded at least two comparable systems, all of which are documented. But the RAF system appears to be strangely absent.

I'm not decrying our own engineers, but if it took the largest industrial power this long to develop a workable IR telescope, how did we Brits have such a system in 1940? Also, the scope needed a goodly supply of power. For the IR sniper scope, the battery pack was the size of a large rucksack.

Sorry Edgar, whilst I can confirm that RAF Mosquito crews did make (limited) use of IR telescopes during late WW2, the whole resin lamp saga pre-dates this. But if you wouldn't mind ploughing through the files to (hopefully) prove me right that would be most kind.

Bob

[Troffa]

Edgar,

I had hoped that this thread could remain on a civil footing, perhaps I was wrong.

I think however that you are being a little disengenious, the majority of the file titles in the National Archive refer to the detection of either uncooperative targets by IR means, ( a technology already demonstrated by RV Jones in 1937) or by the detection of friendly targets purely by the radiant heat of aerodynamic surfaces or exhausts (Neither scenario requiring any IR lighting system on the target aircraft) The most interesting file title I would suggest is that of AVIA 15/1543 :

http://www.nationalarchives.gov.uk/catalog...mp;Summary=True

Further to the above, I reproduce below one of the responses to the thread on PPrune from "Chugalug2"

"Well, my old Varsity and Hastings Pilots Notes confirm that both were fitted with resin lights, and Identification Lights. I mention the latter merely to confess that I had no idea of their use either, other than that implicit in their title. The Varsity Notes merely mention where the RL light switch is. The Hastings Notes are more forthcoming; "The three resin lights in each wing tip are controlled by an on/off master switch and a GREEN-CLEAR-RED selector switch.".

BTW the Downward ID Lights para says; " The three downward identification lights in the fuselage nose are controlled by a switch on the coaming panel. Red, green or amber can be selected and, by pushing up the small lever on the morsing switchbox, the selected lamp can be used for morsing". It infers that the "colour of the day" and the associated code word could thus be displayed, but such techniques were long abandoned by my time (>1962) together with whatever one used to do with resin lights. Regarding the name, many components were then known by the manufacturers tradename (ie Graviner switches, Decca navigator, etc), though I've never heard of such a company as "Resin".

PS Have just dug out my old AP129 vol2. Under Night Formation it reads; "If dim/bright navigation lights are fitted, the dim setting should be used but,when available, resin lights are much better". So that appears to define their use and their properties, ie they were very dim and thus did not dazzle when in formation at night. It appears that the colours were somewhat variable from the blue of Mossies through to "traffic lights" on Hastings! Could the name be a reference to the dimness of a light shining through resin?

PPS Or how about simply REStricted INtensity lights?"

Full thread here: http://www.pprune.org/aviation-history-nos...esin-lamps.html

Please feel free to contact me offboard if you wish to discuss.

Edited March 29, 2009 by Troffa