Duck egg green .. or..

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24 years 2 months

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Jeepman.

http://amair4raf.blogspot.com/

"No doubt the usual forum gremlin will pop up and bleat that specifications were not always followed, so that any colour opined by him is a better choice. In the absence of any other evidence (as opposed to opinion or "points of view") this author prefers primary source material such as this factory drawing and the contemporary colour cards upon which to base conclusions.

Colour photographs are never to be trusted, especially formatted digital images but note from interest the light and sandy appearance of the 'Dark Earth' in contrast to the other colours."

I Like it. No clouding the issue of 'Sky' with this gentleman for sure. :)

Mark

Member for

15 years 11 months

Posts: 435

Not wishing to hijack in any way..but thought this might be of interest..

I have a Ministry of Aviation Av.P 970 Design Requirements for Aircrarft of the Royal Air Force and Royal Navy publication sat in front of me, which contains a rather nice section with colour sample cards featuring none other than this troublesome "Sky" dated 1st September 1948.

If anyone is interested, drop me a PM as it is surplus to my requirements.

Ta!

Timbo

AP has now found a new home, no longer available :D

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18 years 3 months

Posts: 705

Except for the fact that the original Boeing production drawings quote "Deep Sky Blue" - see the website below for the drawings and the picture on that website is surely a factory shot .

http://amair4raf.blogspot.com/

The drawing is of a B-17E and shows how they would have looked had the RAF actually received any. They were retained by the USA and up to 40 were used in training and combat in what appears to be a British style camouflage. Eventually Britain received 19 B-17Fs under lend lease which went to Coastal Command. They did not use this scheme which was meant for a high altitude day bomber.

The drawing has no relevance to the 20 B-17Cs received by Britain, almost all of which served with 90 Squadron. They were delivered in USAAC camouflage of Olive Drab over Neutral Gray with British national markings. The camouflage was a temporary, distemper type paint. They were repainted, initially Dark Green, Dark Earth over Sky. Paul Lucas, in his article, describes the changes that look place and how that led to the scheme shown on the drawing.

The colour deep sky blue on the drawing is not Deep Sky. The drawing is dated July 1941. The name Deep Sky was not adopted until October 1941.

The aircraft in the photograph is not painted with Deep Sky or a similar colour. The colour is similar to PRU Blue. Deep Sky was darker and bluer than PRU Blue and was developed because of a requirement for a darker blue than PRU Blue.

What Paul Lucas has to say on the drawing and the photograph

There is more information available about the green, brown and blue scheme to Pattern No 2 as applied to the B-17E, as the Boeing drawing for this scheme which was entitled, 'Diagram Camouflage and Insignia (British)', originally dated 2 July 1941, has survived. The information contained in this document raises as many questions as it answers however.

It shows a B-17E camouflaged on the upper surfaces with dark green Fullers TL 8714 and dark earth Fullers TL 8713, to the 'A’ Scheme from Air Diagram 1161, with deep sky blue Fullers TL 8997 on the under surfaces to Pattern No 2. …….

The first question this drawing raises concerns the colours listed on the diagram, because there is a very well known colour photograph of B-17E 41-9141 which is camouflaged in the scheme shown in the drawing, flying in close formation' with 41-9131 which is camouflaged in the USAAF scheme. The first thing which strikes you as you look at this photo is that the shade of green on the upper surfaces of both aircraft appears to be identical. This should imply that dark green Fullers TL 8714 was Bulletin 41 Dark Olive Drab. The problem with this is that the drawing lists two Bulletin 41 colours as identification colours and if the green was Bulletin 41 Dark Olive Drab 41, why does the drawing colour key not say so?

The 'sting' in this question concerns 41-9131 in the USAAF camouflage scheme. If the same
green paint was used on both aircraft, and it is not Dark Olive Drab 41, then 41-9131 is not camouflaged in Dark Olive Drab 41, but a US produced equivalent to Dark Green. Lest anyone jump to the obvious question as to whether it might have been Medium Green 42, the same logic applies, why does the drawing colour key not say so?

For the time being at least, it must be assumed that the colour was indeed Dark Olive
Drab 41, as this would appear to be the most likely colour given that Dark Olive Drab 41 was ultimately accepted by Britain where Dark Green was called for in the camouflage of US-built aircraft from March 1942.

The second question concerns the brown shade on the upper surfaces. The colour photograph appears to show this colour as being a light tone, quite unlike the RAF shade of Dark Earth. It is thought that various US aircraft manufacturers used at least two or three shades of brown as equivalents for Dark Earth, one being a very close match to the British colour, one being not dissimilar to Rust Brown 34, whilst the other has been likened to FS 30279, the tan colour introduced by the USAF during the Vietnam War. Unfortunately, the colour apparent in the photograph of 41-9141 appears to be lighter and more yellow than any of these, being perhaps somewhere near FS 33440.

The third question concerns the shade of blue paint on the under surfaces. According to the drawing, this is 'deep sky blue', but no such colour ever existed in RAF nomenclature and this name would appear to be a colloquial term. The drawing is dated July 1941, but the name Deep Sky was not coined in Britain until October 1941 and the hue apparent in the photograph does not appear to be either dark or blue enough to be Deep Sky, whilst it is too dark to be Sky Blue which was used on the B-17Cs.

It would therefore appear that 'deep sky blue' is a corruption of the term 'special sky blue' which was the term used by Bomber Command to describe the colour 'Cosmic' blue which was later named PRU Blue, perhaps overlaid with the colour Bomber Command wished to adopt for its Fortresses from October 1941, Deep Sky? The blue colour visible in the photograph seems to be very similar to Cosmic/PRU Blue.

The problem with this is that as far as is known, PRU Blue was never manufactured in the US which went its own way with the camouflage of PR aircraft with the development of Haze paint. There is one interesting possibility in that there was a US colour which was not dissimilar to PRU Blue in some respects, Dark Blue 29 which is slightly darker and perhaps more green than PRU Blue.

After it was suggested to him that the colour was similar to that used by the US Navy called Blue Gray.

Paul Lucas replies
It is always gratifying to receive this sort of readers' letter, as it not only shows that someone has actually read the relevant article, but also feels that they have something to contribute which adds to our collective knowledge of the subject.

In this case Mike Starmer has raised a very relevant point in drawing our collective attention to the similarity between PRU Blue and US Navy Blue Gray, which I have to admit, for some reason, did not occur to me at the time I was writing the article on the RAF Fortress Mkl.

Whilst it is unwise to place too much reliance on colour photographs per se, I do think that Mr Starmer's observations are valid. A comparison between the colour chips in the books he mentions does reveal how very similar PRU Blue and Blue Gray appear to be, and I have to agree with him when he says that Dark Blue 29 is a stronger colour than that apparent in the colour photograph referred to in the article.

Whilst I have not yet tried Mr Starmer's paint formulae for myself, I have brushed-out two commercially available modelling paints, one of Blue Gray and one of PRU Blue. These two colours straddle the Blue Gray chip in J Elliott's book, one being slightly lighter, and the other slightly darker. The PRU blue has been checked against, and was found to match, BS 381C 636 PRU Blue. In natural daylight, the colours are almost indistinguishable and could easily be assumed to be brushed-out samples from different batches of the same colour!

Having had this similarity between PRU Blue and Blue Gray now pointed out to me, I am quite happy to retract the suggestion that Fullers TL 8997 Deep Sky Blue might have been similar to Dark Blue 29, and to agree with Mr Starmer's suggestion that it might have been similar to US Nay Blue Gray instead.

Although I am grateful to Mr Starmer for pointing out the similarity between PRU Blue and US Navy Blue Gray, I am kicking myself for not noticing this for myself, especially as I have a copy of J Elliott's book on the shelf behind me as I write! In addition to this, as soon as I read Mr Starmer's letter, I remembered that lan Huntley had noted the similarity between PRU Blue and Blue Gray many years ago, (in 'Scale Aircraft Modelling, February 1986), which I had forgotten about!

Thus I came to experience one of those quintessential Homer Simpson moments, where you realise that it has all gone horribly wrong and that there is nothing further that you can do but to look disappointed and say "Doh!"

The origin of Deep Sky.

Some question still remains as to whether Deep Sky ever found its way onto a 90 Sqn Fortress. Deep Sky originated during 1941 as a result of work carried out by the RAE at Farnborough, to devise a suitable camouflage colour for use on under surfaces of high altitude aircraft. Beginning in January 1941, with the then new colour Azure
Blue, by May 1941, the colour had been progressively darkened by up to 30 percent. The resulting hue, called 'Ultra Blue' by the RAE, was submitted to the Air Ministry on 13 May 1941 where it was discovered to be almost identical to Titanine's Cosmic blue.

These results were shared with the Director of Scientific Research at the MAP who was of the opinion that a much darker shade of blue would give better results than the blues which had been tried up to that time, and by the end of May 1941 further work had been put in hand with two new shades, Dark Ultra Blue and Extra Dark Ultra Blue being ready for trials in June 1941.

On 11 August 1941, A&AEE Boscombe Down wrote to the RAE suggesting that the colour adopted should be similar to Extra Dark Ultra Blue but that it should be more dull, whilst the finish should be as matt as the Night fighter black, (ie Special Night). The entire fuselage surface and wing under surface should be covered with the camouflage blue. The roundels should be deleted.

In the light of this, it would appear that the colour was adjusted slightly, and on 27 August 1941, the RAE wrote to the MAP enclosing a sample panel of the colour which the RAE was recommending for the camouflage of the under surfaces of high altitude aircraft as a result of the trials carried out by A&AEE Boscombe Down. The name Deep Sky was suggested for the new colour and the finish was more matt than the standard Type S finish to obviate the 'sun glint' observed on fuselages at high altitudes.

On 5 September 1941, a Postagram was sent from the Air Ministry to HO Bomber Command and HO Coastal Command informing them that the high altitude camouflage trials carried out by A&AEE at Boscombe Down had indicated that the colour then in use on Fortress Mk Is in Bomber Command and PRU aircraft in Coastal Command was not so good as the Ultra Blue Extra Dark shade produced by the RAE for use in the trials. It was requested that each Command should state whether they wished to undertake operational trials of the new colour themselves before adopting the finish, or whether they wished for arrangements to be made for all high altitude aircraft to be given the new finish on the strength of the RAE recommendation.

The question was debated only briefly at HO Bomber Command in two memos, dated 9 September 1941. In the first memo, the suggestion was put to the Group Captain (Operations) that arrangements should be made to paint the Fortresses in the 'extra dark blue paint' without carrying out any further service trials. The Group Captain (Operations) then sent a similar memo to the SASO who ticked the memo and initialled it 'RS' the following day, with the Group Captain (Operations) being asked to take the necessary action to inform the Air Ministry and 2 Group on 11 September.

The Chief Engineering Officer at HO Bomber Command was informed of the decision in a memo dated 13 September 1941, which stated that the SASO had agreed that Fortress aircraft of 2 Group were to be painted in the 'extra dark blue' as recommended by the RAE without conducting any further trials and that arrangements therefore needed to be made to have this work carried out.

The MAP had been informed of this decision by 25 September, when an internal Minute was circulated to a number of departments stating that the under surface colour recommended by
Boscombe Down for High Flying Aircraft had been accepted by Bomber Command without further trial with the request that this finish should be made available for application to the under surfaces of all Fortresses. It was requested that the new colour be given a proper name and that it should be allocated DTD and Vocabulary of Stores reference numbers. The memo went on to state that supplies of the new colour would be required by HO 2 Group at Polebrook and at Burtonwood, and that arrangements should be made to apply this colour to Fortresses at Aircraft Servicing Units as soon as it became available.

By 3 October 1941, the MAP had arranged to supply the new colour for use on Fortresses. The name given to the colour, as suggested by the RAE on 27 August, was to be Deep Sky and the areas on the aircraft to which it will be applied were those defined by No 2 Pattern, including the sides of the fin and the rudder. This became known as No 2 Pattern (Day). Coastal Command had stated that they were satisfied with Cosmic Blue which was now officially named PRU Blue. The MAP are thought to have given instructions for the B-17Es which were expected to be delivered under Lend-Lease to have Deep Sky under surfaces on 6 October 1941. As can be seen from this, by October 1941 both Bomber Command and the MAP had sanctioned the use of Deep Sky on Fortresses but whether any of No 90 Squadron's aircraft ever received this finish is unknown.

In the past it has been suggested that the only Fortress Mk I to receive Deep Sky under surfaces was AN526, during its time at Colerne in 1942 after the type had been withdrawn from front line service in Bomber Command. AN526 was apparently used as a 'live target' for both radar and interceptors as Fighter Command attempted to develop tactics to counter high altitude bombers as it was expected that the Luftwaffe might shortly begin to operate such aircraft over the UK. It has also been claimed that some 90 Sqn aircraft not only received Deep Sky under surfaces but also Red code letters, but again this cannot be confirmed.

Whether the Fortress Mk Is which were detached to the Middle East in November 1941 ever had Deep Sky under surfaces is also unknown.