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DH Mosquito tail fairing - Monica or signal light?


Dave Swindell

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46 minutes ago, Wez said:

There is a very good picture of the Monica aerial on a Fortress

Yes, there's very good pictures of Monica aerials on heavy bombers, invariably external, pointing aft and mounted under the tail turret. I think we're agreed that the lack of photo's of a similar nature on theMosquito is because it was possible to mount it internally due to the wooden construction of the tail cone.

 

49 minutes ago, Wez said:

all Mosquitoes after a certain point got it whether they needed it or not. 

My point was that it can be shown that some aircraft got the fairing and some didn't at a time when DH were trying to rationalise production, Mosquito colour schemes being a notable case for rationalisation. There must have been a reason for Night Fighters, Bombers and Coastal Command Mosquitos to come off the production line with the fairing whilst PR and trainers came off the line without.

 

58 minutes ago, Wez said:

No Rebecca is a homing system,

You've got the wrong end of the stick here Wez, I know what Rebecca is and what it was used for and agree the Rebecca System wasn't fitted in the tail of the Mosquito. Streety explicitly says parts of ASV II wre incorporated into early versions of Monica, and later parts of AI IV, and you yourself have commented on the similarity of the Monica aerial to that fitted for AI IV.

What I was commenting on was the inclusion in the ASH FBVI drawing above of a single aerial which looks like one of a pair that were fitted to the likes of the Lancaster on the sides of the nose pointing forwards and in the vertical plane, but now rotated to the horizontal plane and pointing aft, this being labelled as a Rebecca aerial.

I was speculating that this Rebecca aerial would have been commonplace by late 42/early 43 when Monica was being developed and may have been repurposed as was ASV II receiver and display in early versions of Monica, ie the aerial noted as being Rebecca is actually part of the Monica System.

I don't know the source of the ASH FBVI drawing above or whether any misinterpretation has taken place, as the the AI IV style aerial for Monica is also shown. Could this type of aerial have been found more effective for later versions? If a Rebecca aerial was used, it would have been just as effective inside the tailcone as later aerials, and it could be that the proximitiy and labelling of these aerials to the fairing we are discussing in drawings has lead to both a misinterpretation of the use of the fairing and because of the origin of the aerials themselves, to a misinterpretation of the systems fitted to the aircraft.

1 hour ago, Wez said:

Sorry, but the Illustrated Parts Catelogue (IPC) is intended for those maintaining the aircraft, they would already be security cleared,

It would also be used by those in the supply chain, stores and manufacturing, who almost certainly weren't cleared for detailed knowledge of secret radio and radar installations.

Is it significant that the drawing shows upper and lower lamp fairings (and possibly a mounting bracket 33?) but not the lamp itself? That would depend on what the other drawings in the catalogue show, eg are the landing lights and navigation lights shown on the  relevant pages of the airframe drawings? If yes, this points to the "lamp" being specialist equipment. If no, then this drawing from a parts catalogue could be trade specific, ie this is what an airframe fitter had access to to order spares from. He would have access to the aircraft and know whether it was fitted with a lamp or a "lamp", but the erk in the stores wouldn't know or need to know if he had to supply Fairing, lamp, front portion. The aircraft fitter would have the relevant security clearance for the aircraft he was maintaining, he would know it had hush hush gear on board but wouldn't know necesarily what it was for or how it worked and wouldn't have access to the manuals for the equipment. The "lamp" would be maintained by technicians cleared and trained for "lamp maintenance" using manuals for this equipment and a separate secure supply chain for parts.

The drawings of other parts of the airframe in the vicinity of other sensitive equipment could also give an indication of whether we should be looking for a lamp or a "lamp" in the terminology used for descriptions of other airframe parts relating to radar and radio installations etc.

2 hours ago, Wez said:

it could however, serve as a useful mount for an externally mounted aerial that we haven't found any evidence for...   ...yet.

We do have two small snippets, Andy's parts catalogue that indicates that the fairing is for a lamp, and the photo in Howe p61 of NF30 MM747/G which shows a dark dome shape behind the fairing. This is specifically noted as being Monica tail warning radar, and shouldn't be dismissed lightly. Stuart Howe had an in depth knowledge of Mosquitos and worked for many years on Mosquito restorations at the Mosquito Aircraft Museum. The fact that I don't recall seeing photo's of the dark dome shape on other Mosquitos, and the /G suffix on the serial seem to indicate that this was a trial installation only. It could be that the lamp fairing and mounting was used for a trial installation of some form of Monica aerial that was either not proceeded with or moved internally. Whatever it was, there was definitely something mounted there in this instance.

 

2 hours ago, Wez said:

All of this discussion is interesting but we should remember, there are basic engineering principles here (aerial size, placement and systems principals of operation), and the way the RAF carry out modifications to aircraft and how that documentation sits outside of the basic aircraft document set.

Wholeheartedly agree with that, I was a ships Chief Engineer until recently, and one bulkhead of my office was full of shelves of techical documentation and plans for every aspect of the ship; finding all relevant info of an installation in the various drawings catalogues and manuals could be quite time consuming, moreso the older the ship became after equipment upgrades, replacements and refits.

 

1 hour ago, T-21 said:

HH is also shown as Z i/d system

It's shown as type F or Z, and we have cockpit drawings, parts and wiring leading from them to the tail for type F flasher units and type F switcher and indicator units. It would be logical therefore for the tail unit to be type F as well. It would be useful to know more about both F and Z systems. My current (limited) knowledge is that type F was for visual identification as friendly from astern by nightfighters, and type Z was to identify as friendly and disable stern defensive systems of aircraft ahead of the unit. Type F was a small low intensity system, type Z was much larger and higher powered. I'm happy to be corrected on this with suitable documentation/evidence.

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15 minutes ago, Dave Swindell said:

You've got the wrong end of the stick here Wez, I know what Rebecca is and what it was used for and agree the Rebecca System wasn't fitted in the tail of the Mosquito. Streety explicitly says parts of ASV II wre incorporated into early versions of Monica, and later parts of AI IV, and you yourself have commented on the similarity of the Monica aerial to that fitted for AI IV.

What I was commenting on was the inclusion in the ASH FBVI drawing above of a single aerial which looks like one of a pair that were fitted to the likes of the Lancaster on the sides of the nose pointing forwards and in the vertical plane, but now rotated to the horizontal plane and pointing aft, this being labelled as a Rebecca aerial.

I was speculating that this Rebecca aerial would have been commonplace by late 42/early 43 when Monica was being developed and may have been repurposed as was ASV II receiver and display in early versions of Monica, ie the aerial noted as being Rebecca is actually part of the Monica System.

I don't know the source of the ASH FBVI drawing above or whether any misinterpretation has taken place, as the the AI IV style aerial for Monica is also shown. Could this type of aerial have been found more effective for later versions? If a Rebecca aerial was used, it would have been just as effective inside the tailcone as later aerials, and it could be that the proximitiy and labelling of these aerials to the fairing we are discussing in drawings has lead to both a misinterpretation of the use of the fairing and because of the origin of the aerials themselves, to a misinterpretation of the systems fitted to the aircraft.

Ah, sorry, my mistake.

 

Would a Rebecca aerial be repurposed for radar detection?  Highly unlikely, they're frequency bands apart, the Rebecca dipole would be too big.

 

As to using some parts of the Rebecca system in the Monica and other systems, highly likely, why go to the bother of designing a completely new system when with a few tweaks, changes of and modifications you've got a repurposed system.

 

21 minutes ago, Dave Swindell said:

We do have two small snippets, Andy's parts catalogue that indicates that the fairing is for a lamp, and the photo in Howe p61 of NF30 MM747/G which shows a dark dome shape behind the fairing. This is specifically noted as being Monica tail warning radar, and shouldn't be dismissed lightly. Stuart Howe had an in depth knowledge of Mosquitos and worked for many years on Mosquito restorations at the Mosquito Aircraft Museum. The fact that I don't recall seeing photo's of the dark dome shape on other Mosquitos, and the /G suffix on the serial seem to indicate that this was a trial installation only. It could be that the lamp fairing and mounting was used for a trial installation of some form of Monica aerial that was either not proceeded with or moved internally. Whatever it was, there was definitely something mounted there in this instance.

I do recall seeing something like the additional dome and that would make sense, this is really pushing me towards looking at my Mosquito references.

 

24 minutes ago, Dave Swindell said:

The aircraft fitter would have the relevant security clearance for the aircraft he was maintaining, he would know it had hush hush gear on board but wouldn't know necesarily what it was for or how it worked and wouldn't have access to the manuals for the equipment. The "lamp" would be maintained by technicians cleared and trained for "lamp maintenance" using manuals for this equipment and a separate secure supply chain for parts.

But these parts wouldn't find their way into the IPC, they would be kept in the separate SRIM documentation, no need for euphemism in the IPC.

 

25 minutes ago, Dave Swindell said:

My point was that it can be shown that some aircraft got the fairing and some didn't at a time when DH were trying to rationalise production, Mosquito colour schemes being a notable case for rationalisation. There must have been a reason for Night Fighters, Bombers and Coastal Command Mosquitos to come off the production line with the fairing whilst PR and trainers came off the line without.

Without checking my references I can't say they didn't.

 

This is an interesting conundrum!

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1 hour ago, T-21 said:

Does anybody have a picture of a Mossie cockpit or pilots notes showing this ?

It's shown in both ASH FBVI and NF30 drawings above. It's not clear whether it's mounted behind or throuhg the windscreen, I'd suggest the former is more likely. There is also the possibility that it was hand held, not mounted, which might account for it's non appearance on other drawings.

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16 hours ago, Anthony in NZ said:

But he was telling me that the lamp in the starboard wing leading edge (which I always assumed was another landing lamp) was where this beam came from.

Further thoughts on this one, after thumbing through both Howe and Thirsk illustrated histories:-

A lot of photo's of aircraft with the starboard leading edge lamp arrangement show that they also retained the underwing landing lights , the remainder I couldn't positively say whether they were retained or deleted (angle of photo, drop tank in the way etc) - why install extra landing lights? were they for another purpose?

The starboard leading edge lamp doesn't seem to have been introduced until the end of the war. Late war photo's invariably show no leading edge lamps, those with are mid 45 or later. This would appear to rule out wartime use of type Z IR in this position, but doesn't preclude it's use post war.

 

Another thought re Canadian B25's with external tail mounted yagi aerials, was there a change to a metal tail cone with Canadian manufactured Mosquitos, which would preclude it's internal mounting? or was it mounted externally for other reasons?

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3 hours ago, T-21 said:

A mention of Z equipment here  https://mraths.org.uk/?page_id=480

 From the above link "An interim system (known as Type Z), which provided some measure of identification was in use. It involved motor driven cams which flashed a coded signal from infrared lamps of the (friendly) target, observable with an IR telescope fixed to the gunner’s sight arch along with the gun-sight and the AGLT collimator. The code was changed for each mission".

This sounds like the type F flasher unit and my interpretation of type F recognition by the nightfighter Nav/Radar operator. The lamps in the Lancaster nose look of a size that could be wing leading edge mounted, or for that matter, for a single one to be fitted in the fairing in question. If this was what was mounted here and only visible from below and behind, why fit it to CC aircraft which flew at low level in daylight?

1 hour ago, Wez said:

This is an interesting conundrum!

Certainly is!

 

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So much to catch up on as I was extracted from this interesting discussion due to some kind of annual celebration. Happy New Year to all by the way!

 

I have read over the posts since I submitted the excerpts from the IPC, thus ruining Dave's tea and walk, and have a few comments. Rather than quote the various snippets, I will list the topics here and offer my two cents. First, though, be aware that I possess nowhere near the level of knowledge that you guys have about the various electronic devices being discussed; I'm but a humble modeller who happens to take a great interest in learning abut my subjects and who happens to be part of an organization that is restoring a P.R. 35 Mosquito and who also has fortunate access to some documents that many do not have.

 

The Illustrated Parts Manual

 

This document is in very limited circulation and comes from the de Havilland Aircraft Heritage Centre and has a somewhat mixed provenance. The title of the document is "Illustrated Parts Manual de Havilland DH98 Mosquito Mk. NF XIX (Swedish Airforce J30)" and the introduction carries the following description: " This manual has been created using information from a variety of sources, primarily the Swedish Air Force J30 Illustrated Parts Manual and AP 2019 C & E, Volume III, Parts 1 & 2 , The RAF Schedule of Spare Parts for the Mosquito T Mk.III and FB Mk.6. All the parts numbers listed are copied from the Swedish J30 Manual and where a correlation exists the item description has been taken from the Vol. III. There are occasions where I have had to find an item description from alternative sources as no equivalent part exists in either the Mosquito T Mk.III or FB.VI."

 

The original British Air Publications covering the various Mosquito marks, to my knowledge, do not have illustrated parts manuals but rather use parts lists that do not use diagrams but rather list the  thousands of individual parts that make up the aircraft along with, among other things, instructions on how to order spare parts. That said, I cross checked my copy of AP2653T Volume III Part 1 covering the spare parts for the P.R. 35 and the part numbers for the tail cone fairings for this later mark still carry the same description, namely that they are for a "Lamp". Therefore, any doubt arising from these parts being some sort of a Swedish peculiarity can be dismissed.

 

Incidentally, parts 33 and 34 that appear in my excerpts are called up as "Bracket, Lamp Support, LH" and "Bracket, Lamp Support, RH", respectively.

 

The Diagrams in Streetly's Aircraft of 100 Group

 

I looked over my copies of these diagrams early in the discussion and, quite frankly, interpreted them as marking the general locations of separate and not necessarily coincident installations. I say this because I could not believe that the Monica (arrow shaped) and Rebecca (Yagi style) aerials could possibly fit together within or outside of the cramped tail cone unit. Keep in mind that there's a lot of other stuff within the cone as well, not the least of which are the elevator controls which necessitate bulges to fit the large bell crank. This is just my interpretation and not based on a known fact that these were non-concurrent installations.

 

I would add that the same publication, on page 140, shows a profile of Mosquito DZ410 with the rear Monica antenna emanating from what appears to be the extreme rear end of the tail cone under the nav light.

 

The photos from Anthony in post #14

 

Excellent references Anthony, thank-you! I note that the "Avspec interpretation" has the lower fairing face placed on a bit of a rake whereas the unrestored example has the face perpendicular to the fuselage axis.

 

Leading Edge Lamp

 

When Anthony brought up the discussion he had with the owner of TE910 about a leading edge lamp, I recalled something I had read on this but I can't for the life of me remember it now. I will continue to look.

 

Photo of MM474/G

 

This photo that appears in Howe's Illustrated History on page 61 is so far the best that I have seen of a period use of the fairing. I have also a very grainy distant shot taken of the underside of an unidentified Mosquito showing what appears to be a similar black dome in the position of the fairing. It would be helpful to know the dimensions of the Monica or Rebecca antennas to confirm if either one of these could fit into such a feature.

 

Infrared Telescope

 

Thirsk's Illustrated History on page 174 has a picture taken from inside the cockpit of an airborne NF 36 of 29 Squadron showing a circular clamp to the immediate right of the gun sight. The clamp is empty and there is no hole in the windscreen. I don't think I have ever seen a picture of a Mossie windscreen with an object protruding out of it but that doesn't mean that it did not exist.

 

Great discussion guys!

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Right-O getting a bit of a handle on a few things here... This is taking some time as I have 1000's of Mosquito sheets and drawings. Please be patient.

 

First thing Almost impossible to find anything on Monica in all my drawings and Mod sheets. Practically nothing.

Regarding the tail fairing, I think it's fairly conclusive this was for the Type 'F' Flasher unit.

 

Mod 261 : 19/10/43 : 'To make provision for fitting equipment Type 'F'  For Mks VI, N.F.30, and in design of N.F.30 & 38

Drawing (cant find it again-ugh) for this shows the plate attached behind Navigators knees as in my prev cockpit photo.  But also the Flasher unit mounted as per Tony's HJ711.  Interestingly there is no mention of fitment to N.F.II airframes.  I will need to look at photo's as I suspect tailcones with this provision were used on many marks as they were tailcones in RAF stores stock etc. So probably got fitted to numerous airframes?

 

Now, more interestingly the 'Z' equipment!

 

Mod 646 : Classification 4B : 27/7/44 : 'To introduce equipment Type 'Z' in wing (fixed Parts)  For Mk's T.III, VI, & N.F.30 

I don't have this mod sheet or drawing and would love to see it. Then

 

Mod 742 : Classification S.O.O. 2 C.W.P 8/8/44 : To Introduce equipment Type 'Z' (removable parts) For Mk's T.III, VI, & N.F.30 (see attached Courtesy Dave Brown-I hope you don't mind me sharing this mate?).

376_zps5es1yvlr.jpg

 

No where in any of the mods was there provision to add another landing lamp anywhere (let alone in the wing leading edge).  So could this be part of Mod 646 for the 'Z' infra red? Likely this was included in production and why we see it on so many different types?

 

Over to you.....

 

 

Edited by Anthony in NZ
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13 hours ago, Crimea River said:

I'm but a humble modeller

Ditto, but without your access to actual drawings. I'd love to get a look at the microfiche Mosquito drawings that resurfaced recently. Unsurprisingly most of the drawings available now are of postwar aircraft and we're faced with the problem of determining what was original wartime fit and what is postwar modifications. Thanks for confirming the lamp brackets, by the way.

 

13 hours ago, Crimea River said:

not necessarily coincident installations.

Those were my thoughts exactly, and the reason for my musing on the use of a Rebecca aerial for the Monica system. Without exact dimensions, just by eyeballing photo's I'd say you could get either the Monica aerial or the Rebecca aerial inside the tailcone aft of bulkhead 22 in your parts drawing. The elevator torque tube and associated bellcranks and mass balance weights are all forward of this, the only things aft of this bulkhead are ouor mystery lamp and the tail light(s). The dome shown in the photo of MM747/G is far too small to contain either of the aerials, which is why I sugggest it is some other probably experimental aerial. The profile drawing of the external Monica aerial (and I've seen others as well) is not substatiated by any photo that I've seen. This is, I beleive, profile artists adding an aerial as seen on heavy bombers to the Mosquito because they know Monica was fitted, not because they have any evidence it was there. As I've already said elsewhere, the only aerial I've seen photographed here is Canadian B25's with a vertically orientated aft pointing Yagi which might  be Monica or might be something else. Aerials for known Monica installations are horizontally orientated.

 

13 hours ago, Crimea River said:

Thirsk's Illustrated History on page 174 has a picture taken from inside the cockpit of an airborne NF 36 of 29 Squadron showing a circular clamp to the immediate right of the gun sight

Good spot, I missed that one yesterday. I'm also sure the telescope was mounted behind the windscreen, not through.

 

8 hours ago, Anthony in NZ said:

Please be patient.

:waiting:

8 hours ago, Anthony in NZ said:

Regarding the tail fairing, I think it's fairly conclusive this was for the Type 'F' Flasher unit.

We need to be careful with terminology here, we've definitely established from crown copyright cockpit drawings (ie official sources) that the type F flasher unit was mounted on the bulkhead in the cockpit behind the Nav's legs in both B35 and NF30. These drawings also show a type F switching and indicator unit on the starboard cockpit side by the Nav's elbow. I've also found this switching unit and spare fuses for same on similar drawings for the FBVI, but the flasher unnit wasn't shown on the same drawing. Absence from drawings doesn't necessarily mean it wasn't fitted, equipment is sometimes omitted for clarity depending on the intended use of the drawing and may be shown on other drawings. Presence though would indicate it was a common if not universal fit for that particular mark or marks being covered.

The wiring from the type F Flasher apparently leads into the tailcone on surviving aircraft fitted with or for the flasher, but nobody so far has as far as I know come up with a definite answer as to the exact nature ond location of the equipment at the end of the wires

We've found reference to type F or Z Transmitters mounted in the tail and a lamp fairing in the tail. I've already been castigated for suggesting that "lamp" might be a euphemism, but it could be seen as a grey area whether the Infra Red source is referred to as a lamp or a transmitter. My (modern) interpretation is of an IR lamp being a heat source (pain releif therapy and industrial heating) but an IR transmitter would be a signaling source (TV remote etc)

The Lamp fairing is of a simiar size to the known type Z transmitters in the nose of Lancasters and Fortresses, so this could be the location of the type F Transmitter but the drawings in the Streetly 100 group book reproduced earlier indicate the extreme tail where the tail light was fitted. Is there any significance in the apparent doubling up of the tail light on later Mosquitos where AFAIK the other nav lights remained as single units? Is this extra tail light in fact the type F transmitter?

8 hours ago, Anthony in NZ said:

Interestingly there is no mention of fitment to N.F.II airframes. 

Or Bombers, as noted above, it's shown as fitted to B35's at least.

 

8 hours ago, Anthony in NZ said:

Mod 646 : Classification 4B : 27/7/44 : 'To introduce equipment Type 'Z' in wing (fixed Parts)  For Mk's T.III, VI, & N.F.30 

I don't have this mod sheet or drawing and would love to see it. Then

 

Mod 742 : Classification S.O.O. 2 C.W.P 8/8/44 : To Introduce equipment Type 'Z' (removable parts)

My initial interpretation of this is:-

Mod 646 - Fitted For Type Z - Instructions and modifications for the production line to install the necessary wiring and mounting points for type Z equipment, presumably in and through the wing to the cockpit and or rear fuselage.

Mod 742 - Fitted With Type Z- Instructions and modifications for the MU's and CRU's to fit and connect the actual type Z equipment to the previously installed mounting points and wiring.

I'd also be interested in seeing drawings for these, drawings for mods for type F and Monica would also be exceedingly useful with the current debate!

 

The type Z mod dates would tie in with use in protection from Village Inn, but as I said yesterday, I'm not seeing photo's of the starboard "landing Light" installation until immediate post war. Late mark PR's had the starboard landing lights as well.

Use on TIII's is intreaguing, they were definately fitted with the landing light mods, but why fit type Z to what was essentially a pilot type conversion trainer and not a role trainer. Unless there's some other use of type Z we don't know about it was no use in actually flying the aircraft?

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19 hours ago, EwenS said:

I see that the forum on Mossie.org is back up and running after a 15 month absence.

Thanks for pointing that out Ewen, certainly worth looking at.

 

A quick update on the vertically orientated external Yagi aerial on the extreme tail, Thirsk p90 has a clear picture of KB471, a B25 (but converted to two stage merlins and with bulged bomb bay) The aerial is identified as type 338 Boozer III, and matches the aerial on a Halifax in Streetly C&D p164 simiarly indentified. Thirsk p103 shows a BXVI postwar which also appears to have this aerial. Idle musing, could this be external because there's also an internal Monica aerial which precludes it's placement there?

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  • 3 weeks later...

I just came across this photo of the Z lamps photographed from inside a Lancaster nose, not something I recall seeing as clearly as this before - you often see the two circles on the outside of the blister, but not the lamps themselves. They certainly look of a size that could fit snuggly in the Mosquito under tail fairing.

pic-lanc-bomberaimer.jpg

 

Just for completeness, I found this accidentally in a thread discussing bombsites

 

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On 1/1/2020 at 3:54 PM, Crimea River said:

 

 

Leading Edge Lamp

 

When Anthony brought up the discussion he had with the owner of TE910 about a leading edge lamp, I recalled something I had read on this but I can't for the life of me remember it now. I will continue to look.

 

 

Good photo.

 

To close the loop on the above quote, I found the reference I was looking for that tied the ID lamps to what I thought was the leading edge lamp. The reference is from the FB VI Manual and it reads as follows:

 

"A selector switch (46) for selecting RED, GREEN, or AMBER and a signalling switchbox and key (43) on the starboard side of the cockpit operate the identification lights. The three-position, navigation head lamp switch (53) on the starboard side switch panel enables the head lamp to be in circuit with the downward identification lamps and to be used in conjunction with these for steady illumination or for morsing."

 

So, though not specifically referring to the leading edge head lamp, it's clear that the head lamps on the FB VI were certainly capable of being used in conjunction with the Red/Green/Amber ID lights.

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Very interesting discussion gentlemen, much of which goes above my head.

 

Therefore, please excuse my ignorance, but I have to ask.

 

This equipment is listed for only select Marks of Mosquito, yet some Squadrons were operating other Marks around this time (eg. 456 Squadron had Mk XVII nightfighters)

 

Is there any reason for limiting installation to only a few Marks?

 

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9 minutes ago, Peter Roberts said:

Very interesting discussion gentlemen, much of which goes above my head.

 

Therefore, please excuse my ignorance, but I have to ask.

 

This equipment is listed for only select Marks of Mosquito, yet some Squadrons were operating other Marks around this time (eg. 456 Squadron had Mk XVII nightfighters)

 

Is there any reason for limiting installation to only a few Marks?

 

Specific role, as 456 Sqn wasn't a 100 Group squadron I'm guessing it was used for ADGB then later as a nightfighter unit over the front.  The 100 Group squadrons used it to actively go hunting for German nightfighters by luring them onto their Monica transmissions.  That's my take on it anyway.

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5 hours ago, Wez said:

The 100 Group squadrons used it to actively go hunting for German nightfighters by luring them onto their Monica transmissions. 

Whilst this is correct, the purpose of the thread is to establish what the fairing under the Mosquito tail was for, and we're pretty certain now that this has nothing to do with Monica which was fitted internally inside the tail fairing.

 

5 hours ago, Peter Roberts said:

Is there any reason for limiting installation to only a few Marks?

I'd suggest, as Wez did, that this is role specific.

We think the fairing was for a lamp, and that this was the type F infrared source controlled by a flasher unit in the cockpit, however we don't know how this was used operationally.

We don't know whether all aircraft with this fairing were fitted with the lamp, or whether some were just fitted for the lamp (ie the lamp could be fitted, but wasn't normally carried)

The fairing was fitted to aircraft outside 100 group eg Coastal Command, and a Met flight B.IX I'm currently researching/modelling among others, whilst in the same timeframe other units as you say didn't have the fairing/lamp.

If we knew more about it's operational use it would enable us to work out why certain aircraft were fitted this way and otheres weren't.

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  • 3 weeks later...

Hi Guys,

 

This is my first post on Britmodeller, my spiritual home for many years having been the Flypast Historic Aviation Forum but as I'm sure some of you are aware, that site has virtually collapsed in the wake of yet another "new and improved" upgrade and I'm left feeling semi-homeless.

 

I'm not a modeller so I doubt I will contribute to many threads on this site but discussions such as this one always suck me in, especially as I have been researching many and various topics related to wartime British aircraft, their equipment and operations for more years than I care to recall.

 

Since retirement, I have been fortunate to have been able to spend many days in The National Archives and my collection of research material now consumes gigabytes of storage on my drives.

 

One area I have devoted a small amount of time to is the various tail warning devices used by Bomber Command, i.e. Monica, Boozer, etc.  While pursuing this topic I came across a file in the Air20 series (Papers accumulated by the Air Historical Branch) which summarises the position with regards to A.G.L.T . and Types 'F' and 'Z' equipment in late 1944 and early 1945.

 

I think there is no doubt that the object housed in the rear fairing of the Mosquito is the lamp for the Type 'F' installation.  Here's a couple of extracts from the report which throw some light (my first pun?) on the subject.  Unfortunately, all this photo-hosting malarkey has taken me by surprise and I cannot upload images in the same way I'm so used to on the flypast Forum, so you'll have to make do with transcripts!

 

I hope you'll find them useful?

 

First extract:

FIGHTER COMMAND OPERATIONAL INSTRUCTION NO.4A/1945
OPERATIONAL USE OF TYPE 'F' AND TYPE 'Z' EQUIPMENT
BY NIGHT FIGHTER SQUADRONS OF FIGHTER COMMAND

INFORMATION

1.    Type 'F' equipment consists of two separate installations, a simple lamp fitted in the tail of the

aircraft which transmits an infra-red beam, and a specially designed telescope fitted in the pilot's cockpit.      

 It is now fitted to all Night Fighter aircraft of this Command, and a considerable number of aircraft of other

Commands, as an additional aid for air to air identification at night.

2.    Type  'Z' equipment consists of a similar lamp which also transmits an infra-red beam, but which is fitted

in the leading edge of the wing of the aircraft.      This equipment is designed to identify the aircraft fitted

with it to an air-gunner in Bomber aircraft equipped with A.G.L.T. and Type 'Z' Receiver.

3.    Type  'F' and Type 'Z' equipment will be used in all Night Fighter aircraft of Fighter Command operating

over the Continent as well as this Country.

4.    Signals from Type  'F'  transmissions will normally be received up to a range of 1.5 to 2 miles,   the

cone of reception being 12 1/2° either side of this line of flight of the aircraft.      Type 'Z' transmissions

have a similar performance to that of Type 'F'.

 

Second extract:

I am directed to refer to your communication dated 29th January, 1945, reference 452.05 regarding the above

subject.  The following is the fitting programme for British aircraft with details of the progress which has been

made:-

(a) Type 'F'

(i) The programme is to fit all Mosquito night fighter squadrons in Bomber Command, Fighter Command and 2nd T.A.F.

with Receivers and Transmitters, and this programme has now been completed.

(ii) It is also intended to fit all Bomber Command aircraft and the Mitchell and Mosquito bomber squadrons of 2nd

T.A.F. with Transmitters.  The fitting of Bomber Command aircraft has not yet started as the necessary

modification sets are not yet available.  The modification sets for some of the Mitchells of 2nd T.A.F. are now

being issued.
 

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Thanks for the info Air Ministry. It does add to our "enlightenment`....ahem. It confirms a lot of the discussion but what leaves me wondering are a couple of things:

 

1) The date of the second document is already 1945 and refers to fit-outs yet to be completed on 2TAF Mosquitoes and all Bomber Command aircraft. It makes me wonder whether the fairing on the Mosquito was for an earlier purpose that was found to be a convenient mount for the new equipment. This was suggested in an earlier post an some Mosquito photos with the fairing predate January 1945.

 

2) Reference is made to transmitters and receivers. Whereas the "transmitter" could mean the signaling box referred to earlier, we now have a "receiver" whereas reference was also made to a special telescope. So does the January document refer to some kind of updated Type F system?

Edited by Crimea River
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Hi Air Ministry

 

I too am an orphan from Key.  That forum was such a wonderful resource for many of us rebuilding Vintage aircraft and dabbling in a bit of scale modelling.  I got some great advice and helpful tips for the rebuild of My Auster T.7....such a shame its such a mess now.

 

Your research is very interesting and makes sense.  These all make sense to what I have discussed, researched and found discussed here.

 

Andy (Crimea River) poses an interesting couple of questions.

 

Do you or anyone have images of these lamps, transmitters and receivers?

 

Cheers and thanks all

Anthony

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Crimea River,

 

Here's a paragraph from another document in the same file.  I think it should allay your concerns about differing versions?

 

3.  Description of Equipment.   The infra-red scheme consists of a receiver (telescope) through which it is possible to see the radiation of a coded flashing infra-red transmitter fitted in another aircraft.  These transmitters cover a limited cone of view and on the approach of an aircraft the operator looks through the telescope and if he sees a coded beacon, no further action need be taken.

 

I can't help with possible alternate uses for the recess in the tail cone.  I have Volume Is for various versions of the Mosquito - fighter, fighter-bomber and bomber, but they all show a standard, unmodified cone.  That said, I wouldn't expect mods such as this to necessarily turn up in a Vol. I anyway, eg, there's nothing in the Lancaster AP to illustrate the Type Z installation.

 

Anthony in NZ, I have a copy of (Bomber) Command Modification No. 67 which fully covers the installation of the Type Z equipment in the Lancaster and Halifax, down to lengths of wiring, fuses and nuts and bolts, and all well-illustrated.  Sadly, I have nothing similar on the Type F equipment, although I would expect most of the equipment to be similar.  I've also got nothing on the "receiver", either in a gunner's turret or a Mosquito cockpit, although I'm sure I've seen a photo of the latter but I cannot recall where or whether I saved a copy of it.

 

That's the joy of researching at Kew, you rarely get a complete picture from just the one file, and finding the elusive "other" files can consume most of your precious time down there.  Sometimes it's better to stick with simpler topics in order to maximise your results.

.

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  • 1 month later...
On 12/31/2019 at 3:51 AM, Anthony in NZ said:

Better be quick, Photobucket is working...

The rectangular panel on the armor plate is where the Flasher unit went

garden%20004_zps4tzatsjn.jpg

 

Ugh...It stopped working again  This is a Std Motors built TE910/ NZ2336

 

I will post again when I can

 

Anthony, this is completely OT but I'm starting a Mosquito build  Can you tell me if that fire extinguisher is authentic?  Was the original brass or painted red and this one is just heavily weathered.

 

Same for those "pouches" next to it (what are those anyway)?  Are they original?   If you have any other detail shots like this one, feel fee to share, they would be immensely useful.  

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2 minutes ago, 11bravo said:

Same for those "pouches" next to it (what are those anyway)?

They look like flare signal cartridges to me, latter day ones had metal cases.

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