Mosquito Resin or IR Lights

[Edgar]

Perhaps you might care to agree, that the "man in the factory where the scopes were made" story is as anecdotal as the evidence that I presented based on my own meetings with RAF aircrew. As the scopes were made to Government contract, unless there was a specific order from the Air Ministry or a particular specification of the RG scope purely for airborne use, I doubt that anyone "at the factory" would have known where the items were being deployed and by whom.

Even if he was management? He knew enough to state that, after operations, the scopes were locked away in a cupboard, which indicates more than a passing knowledge of their operational use.

Any aircraft that crashed in occupied territory would be examined by Luftwaffe technical personnel to see if juicy items such as radar or navigation aids were fitted. A passive IR system would beeasy for the Germans to deduce as they had also been working in this area. What measures would be taken to safeguard the RG Scope in operational use?

By not allowing them to be used over France until mid-1944, perhaps?

The references are fascinating, or would be, but I'm not sure how many tanks nightfighter Mosquitoes (plus Lancasters and Halifaxes) encountered during their night operations.

[Edgar]

Interestingly, the obituary of one Edward Lee, appeared in the Telegraph on 22 March 2009.

Professor Lee is credited with, amongst other things, the invention of the IR Spectrometer. He was also involved in the development of radar.

As a result, apparently, of his work in both of these fields, he went on to invent and prove an infra-red identification system for RAF aircraft, in order that crews would be able to visually identify friend from foe at increased ranges in the dark. The system worked, it seems, by the intermittent emission of pulses of IR light from suitable lamps mounted "on the tailfins", which pulses were visible via devices equipping the crews of other aircraft.

It might be assuming too much, of course, but maybe this is the same Edward Lee?

Interestingly, it seems that, as late as mid-1944, even the pilots weren't told the whole story regarding the scope.

Edited March 30, 2012 by Edgar

[bobgpw]

I suppose if Mossies flew very low they might meet IR equipped tanks travelling in convoy - imagine the paperwork! The steam powered Halifaxes left such large contrails you'd have to be blind not to see them so there are no resin lamps fitted to this particular mark of aircraft. The weight saving of deleting the lamps and wiring did not assist with overcoming the drag from the funnel........

Edgar, it has been fun kicking this back and forth, but I for one doubt we'll ever get to the bottom of whether resin was a codeword or just a sticky substance that annoys insects. I wish you well in your endeavours but I for one am calling time on this.

Genuinely, I have been thoroughly entertained by your knowledge and dilligence.

Bob

[BruceG]

I think there may well be 'Resin Lights' and 'Resin Lights' here.

For what its worth, I can offer some physical evidence - I have several boxes of the covers mentioned elsewhere; with Red, Green, and clear filters. There is also a wooden stowage box, which states 'Resin light covers'. It contains four covers, of the same type.

Having had some experience of working on the Mosquito aircraft at the de Havilland museum, these resin lights are present on the B35; the covers I mention fit them perfectly. I think that in this instance they are best described as formation keeping lamps.

I have no reason to doubt Edgars research, but I wonder if we are looking at two answers to one question here.

Bruce

[MilneBay]

I think there may well be 'Resin Lights' and 'Resin Lights' here.

For what its worth, I can offer some physical evidence - I have several boxes of the covers mentioned elsewhere; with Red, Green, and clear filters. There is also a wooden stowage box, which states 'Resin light covers'. It contains four covers, of the same type.

Having had some experience of working on the Mosquito aircraft at the de Havilland museum, these resin lights are present on the B35; the covers I mention fit them perfectly. I think that in this instance they are best described as formation keeping lamps.

I have no reason to doubt Edgars research, but I wonder if we are looking at two answers to one question here.

Bruce

I have been following this discussion and I am inclined to agree with you. My vague recollections are that resin was also a common term for the early plastics and while there was, as Edgar's research shows, some form of IR device with a code name of Resin, that also the term was was used for the coloured "plastic" clear covers for ordinary lights.

Edited April 1, 2012 by MilneBay

[Edgar]

A bit more filling-in to the story/saga/discussion:-

I finally managed to get hold of that Kew file, but it was too large to make a thorough examination in the time I had available. However, resin lights started life as a simple recognition device for twin-engined aircraft only, and for use only over this country. They had three coloured filters, red, green & yellow (later changed to white,) and were initially placed at the rear of the extreme wingtips (the two clear covers on early Mosquito bombers, perhaps?) There were complaints that they were too bright, if they had to be capable of being seen at a reasonable difference of about 500 yards, since, close to, they were too visible, and therefore a danger.

In 1943 there is mention of modifications being made to the lights, and of using 4 watt bulbs (which ties in with the recorded complaints of them being "as dim as a Toc H lamp.") As I understand it, a 4 watt bulb would appear much brighter in an IR scope, than with the naked eye, but that information remains to be found. Intriguingly, I've seen one reference to "Primrose," in context with nightfighters, but can only wonder if this refers to the appearance of a small bulb on an IR screen.

It's beginning to look as if Bruce's comment, about "two answers to the same question," could be spot on, especially as there's mention, in one file, about combining the IR timing with that of the resin lights. One other point, in the first mention of these lights, resin is in inverted commas, which indicates a name, not the material in which they were constructed.

I've now discovered definite proof that the IR scopes were made here, in High Wycombe (about 1/2 mile from where I live,) by a company with its head office in Brentford, who were still working in IR during the first Gulf War, which explains why I can't find any information on them, since, even though they no longer can be found at Companies House, any files, that might have entered Kew, will remain closed for 30 years, and that makes any chance of me ever seeing them extremely problematic.

The company has gone from here, of course, but I did find one of their letterheads, and one of the directors was an A.G. Frazer-Nash (plus a string of letters after his name,) and some turrets were, of course, made by a Frazer-Nash company.

[chaddy]

I'm not trying to re-open this can of worms. However, whilst researching some information on 15 OTU (1943-44), I happened upon this information.

29th Sep 1941.
F/Lt. STUBBS and F/O. RYALLS carried out day rehearsal for searchlight S.L.C. trials. W/Cmdr EVANS and F/Lt. ASHFIELD tested telescopic sight on Beau. 2078 by night. F/Lt. STUBBS and F/O. RYALLS took pff (sic) for night S.L.C. trials but were recalled owing to cloud. W/Cmdr EVANS flew again tonight on new type resin lights test with a WELLINGTON from No.15 O.T.U. HARWELL as target.

Further up the page I found this:

7th Sep 1941.
Flying Officer RICKETTS with Flying Officer RANDALL and Sergeant YUILL as operators tested A.I. interceptions under gyro control in Havoc 437. Flying Officer RYALLS did full Mark VI tests in DEFIANT. Flight Lieutenant STUBBS did same tests at 20,000 feet. Flight Lieutenant ASHFIELD departed to WATCHFIELD for blind approach course. At night Wing Commander EVANS did night glass tests and visual approaches on HAVOC burning new type resin lights. Flying Officer CLARK made Unit's first night test of Merlin Beau without exhaust dampers. In spite of twin sheets of flame from exhausts that were visible from 3 miles distance CLARK made surprising pronouncement that he considered Merlin Beau suitable for night operations.

8th Sep 1941.
Flying Officer RICKETTS with Flying Officer RANDALL and Sergeant REECE as operators tested gyro controlled A.I. approaches in HAVOC. Wing Commander EVANS did further tests of the new resin lights on HAVOC.

I'm sorry if these references have already surfaced in this thread, but I only joined it late and I haven't really digested all the posts.

There may be further references, so here is the url for anyone interested:

http://sussexhistoryforum.co.uk/index.php?topic=3280.60;wap2

Cheers

[nickds1]

Apologies for resurrecting an old thread, but I have one of these 5C/3023 boxes (new - in original box) - lovely bit of kit.

The schematic is on the inside of the back cover - it shows the "RESIN" lights as two simple incandescent bulbs sharing a 5A fuse with the "Formation Up Ident Light" (a single lamp) that was on top of the fuselage.

RESIN is controlled by a single on/off switch - nothing fancy. All the other lights controlled by the box can be switched (on, off or Morse) to one of two Morse keys, but not RESIN. Also, most of the signalling lights have an intensity adjustment of off, dim or bright - again, not RESIN.

HTH

Nick.

Edited January 4, 2014 by nickds1

[gingerbob]

Mention is made of "not to go over the continent" (my phrasing) until mid '44. When was it that NF (radar equipped) Mossies were allowed to accompany the bomber stream?

bob

[Wez]

Mention is made of "not to go over the continent" (my phrasing) until mid '44. When was it that NF (radar equipped) Mossies were allowed to accompany the bomber stream?

bob

I think the restriction was to prevent centimetric radar technology being discovered in crashed aircraft prior to D-Day, certainly 100 Group Bomber Command Night Fighter Mosquitos carried invasion stripes so I'm guessing at some point just after D-Day, the AI Mk.X radar equipped Sqns returned to BS duties by the end of August 1944 according to Streetly in 'Confound and Destroy'.

Wez

[chaddy]

There was an incident on the night of 28/29 September, 1944 when Mosquito NT179 was shot down by another intruder over Belgium. RAF Form 1180 states the following:

"A/C shot down by friendly A/C in mistake for JU88. A/C was not showing Resin Lights. (note use of capital letters).

IFF not switched on. Shot down by friendly fighter.

Every effort is being made to obtain night glasses for all air crew".

To me this suggests that the "Resin Lights" were an addition to IFF, as the implication is that one of the reasons for NT179 not being identified was due the the fact that "Resin Lights" were not showing.

Edited January 5, 2014 by chaddy

[nickds1]

There was an incident on the night of 28/29 September, 1944 when Mosquito NT179 was shot down by another intruder over Belgium. RAF Form 1180 states the following:

"A/C shot down by friendly A/C in mistake for JU88. A/C was not showing Resin Lights. (note use of capital letters)

On the box, RESIN is all capitalized - there again, so are all the other labels - if I could work out how to add attachments in this forum, I'd post the photos of the panel and the schematic....

[Edgar]

I think the restriction was to prevent centimetric radar technology being discovered in crashed aircraft prior to D-Day,

Sorry, but no:-

[Wez]

Sorry, but no:-

Ah ha, very useful - have you in your digging through the archives at Kew come across anything that shows the infra-red receivers and how it was mounted?

Wez

[gingerbob]

I may have thrown a spanner in- I think that there WAS a restriction on centimetric radar, affecting NF Mossies, but I just thought that the timing of allowing IR to go "ashore" might have some relation to the advent of "escorting" NF Mossies, who would be equipped to "see" the IR equipment. It might have been a whole package of technology that was cleared at a certain time, or each clearance might have been individual, with different aircraft affected.

This probably isn't any better at explaining where I was coming from!

bob

[Wez]

I may have thrown a spanner in- I think that there WAS a restriction on centimetric radar, affecting NF Mossies, but I just thought that the timing of allowing IR to go "ashore" might have some relation to the advent of "escorting" NF Mossies, who would be equipped to "see" the IR equipment. It might have been a whole package of technology that was cleared at a certain time, or each clearance might have been individual, with different aircraft affected.

This probably isn't any better at explaining where I was coming from!

bob

I understand where you're coming from on this and I too think there would have been a bucket load of technology we'd want to keep up our sleeves until we needed it.

It would be very interesting to see this equipment, how it was mounted and how close you had to get before you could make a good identification without becoming a target yourself first!

Wez

[Test Graham]

There certainly was an early restriction on centimetric radar, which is why the intruder Mosquito Mk.IIs were still equipped with the arrowhead Mk.IV AI. However, this will have been withdrawn when H2S began being used on bombers, and it was the magnetron from a shot-down bomber (near Rotterdam) that gave the Germans awareness. I can't quote a date offhand, but logically early-ish 1944 and not linked to D-Day in any way. Use of the centimetric radar over Europe will presumably be detailed in the books on 100 Group.

Centimetric radar was cleared for 100 Group in May 1944, following the Nuremberg disaster. German jamming of AI Mk.IV had rendered the Serrate-equipped Mosquitos of 100 Group fairly ineffective since late 1943. Shortly after the clearance the AI Mk.X squadrons were taken away for Diver patrols... Source "Confound and Destroy", Martin Streetly.

Edited January 5, 2014 by Graham Boak

[chaddy]

I've turned this up.

"WW2 RAF Infra-Red Viewer 5C/3157 (Tabby type F)

Offered for auction is a WW2 Air Ministry / RAF Tabby Type F infra red viewer. This item has the RAF stores reference 5C/3157, and would have been used as a visual IFF (Identify Friend or Foe) in bombers and fighters to identify friendly aircraft via a flashing infrared beacon mounted in the tail.

It consists of a black painted clear plastic tube which houses the image converter and eyepiece, and a brass tube that contains the objective optics. The device requires a very high voltage (around 3000V) to operate, which would have been produced by a separate power supply connected via the braided EHT lead.

I would describe this item as being in good condition. There is some slight paint loss on it, but the rubber eyepiece, although dirty is still supple. I do not know whether this works as I have no way of testing it.

The device is about 5.7cm in diameter and 18cm long, and the unpackaged weight is approximately 440g."

I'm not sure the description of the way it operated is correct ……"via a flashing infrared beacon mounted in the tail". However, it's the first time I've seen a description.

[Wez]

I've turned this up.

"WW2 RAF Infra-Red Viewer 5C/3157 (Tabby type F)

Offered for auction is a WW2 Air Ministry / RAF Tabby Type F infra red viewer. This item has the RAF stores reference 5C/3157, and would have been used as a visual IFF (Identify Friend or Foe) in bombers and fighters to identify friendly aircraft via a flashing infrared beacon mounted in the tail.

It consists of a black painted clear plastic tube which houses the image converter and eyepiece, and a brass tube that contains the objective optics. The device requires a very high voltage (around 3000V) to operate, which would have been produced by a separate power supply connected via the braided EHT lead.

I would describe this item as being in good condition. There is some slight paint loss on it, but the rubber eyepiece, although dirty is still supple. I do not know whether this works as I have no way of testing it.

The device is about 5.7cm in diameter and 18cm long, and the unpackaged weight is approximately 440g."

I'm not sure the description of the way it operated is correct ……"via a flashing infrared beacon mounted in the tail". However, it's the first time I've seen a description.

So we're talking a basic scope, probably hard mounted to the cockpit coaming behind the windscreen probably for use by the Radar-Operator... ...would definitely want to see deatils of how it was mounted but it would appear to be easy to reproduce.

Wez

[Edgar]

I understand where you're coming from on this and I too think there would have been a bucket load of technology we'd want to keep up our sleeves until we needed it.

It would be very interesting to see this equipment, how it was mounted and how close you had to get before you could make a good identification without becoming a target yourself first!

You can see the remnants of the system on the bomb-aimer's cupola of "S for Sugar," at Hendon.

It was designed to be used as a "counter" to "Village Inn," which was a radar-using (not controlled) rear turret, in which the gunner had the scope (probably similar to that found by Chaddy,) and a radar scope in which he could track any approaching aircraft. If there was no flashing (presumably Morse) signal, he was free to open fire, and, being radar guided, he had no need for tracer, so the enemy pilot, literally, would never know what hit him.

Edgar

[chaddy]

Here you go!

http://arnhemjim.blogspot.co.uk/2011/04/wwii-cutting-edge-night-vision.html

[nickds1]

Here's my 5C/3023 unit opened up...

HTH

Nick

[Edgar]

From April 1943 "R.G." equipment, at the request of the Admiralty, was renamed "Type F."

Edgar

[Wez]

You can see the remnants of the system on the bomb-aimer's cupola of "S for Sugar," at Hendon.

It was designed to be used as a "counter" to "Village Inn," which was a radar-using (not controlled) rear turret, in which the gunner had the scope (probably similar to that found by Chaddy,) and a radar scope in which he could track any approaching aircraft. If there was no flashing (presumably Morse) signal, he was free to open fire, and, being radar guided, he had no need for tracer, so the enemy pilot, literally, would never know what hit him.

Edgar

Thanks Edgar, very helpful.

Wez

[Wez]

Here's my 5C/3023 unit opened up...

HTH

Nick

Thanks Nick.

So where was this mounted in the Mosquito cockpit? Somewhere close to the Radar-Operator I'm guessing.

Wez