Hurricane IIB underside colour

[Peter Boer]

I am trying to solve some remaining questions regarding the ML/KNIL aircraft I describe in my new book Aircraft of the Army Aviation Corps KNIL 1937-42 which is planned to be published in the second half of this year. I trust some of you can help me on this one.

The 12 Hurricane IIBs transferred to the ML/KNIL in Java in February 1942 according to interviews had a underside colour of light grey. Former senior mechanic C.W. Bastiaans (who was responsible for three of the aircraft with Z56xx serials) said the colour was almost identical to the light grey paint used by the ML itself, which was American Dupont 71-021 paint. Also former mechanic R.A. Filon said the underside colour was a light grey that almost matched the ML light grey paint used to paint over remnants of the British roundels under the wings.

Is this at all possible given the British data on the Hurricane colours? Or was there, perhaps, a Sky variant that was light grey?

Help is appreciated, regards,

Peter Boer

[Troy Smith]

Hi Peter

Very interesting. the crux here will be the

light grey paint used by the ML itself, which was American Dupont 71-021 paint.

IIRC this a controversial colour, and was used by Curtiss for RAF deleiveries, and it seems RAF Buffalos

http://www.britmodeller.com/forums/index.php?/topic/234907975-raf-brewster-buffalo-colours/

There'a have been some extensive forum 'discussions' on this and the underside of P-40's with the Flying Tigers and P-400's in the Pacific, all painted in this.

edit - another http://www.network54.com/Forum/149674/thread/1271801585/2/DuPont+light+grey+P-40+Tomahawk+undersurface+color

here's a scan of the dupont colours

It seems that despite being called 'Sky Type S Gray' it was the DuPont equivalent of RAF Sky, that this id the reason.

Nick Millman wrote about this on his blog, which is now invite only, but IIRC he makes the point this colour exists in a complex colour space, and it easily mis identified by different people,and remember that mild defects are common in male vision, enough that this is common misperception.

I have no wish to denigrate your mechanics recollection, but have you checked his actual colour vision, as it's been reported that this colour is frequently reported by different viewers as light grey and pale green, existing a subtle 'colour space'

If your mechanic was told the Buffalo underside was 'light grey' then perhaps this is the colour name he associates with this. Hoepfully Nick will supply some info on this, if nothing else, joins his blog for more information.

A couple of other points, I was under the impresssion that ML-KNIL Buffalo's were delivered with aluminium laquer undersides, and uppersurfaces in 'old leaf/new leaf'

http://www.ipmsstockholm.org/magazine/2005/09/stuff_eng_dutch_af_colours_02.htm

so when did the Buffalos get repainted, or were they one supplied by the British?

Also, did you ever ask about the speculation about repainted UPPER on Ml KNIL Hurricanes?

The emergency-supplied P-40E and Hurricanes received Dutch national markings, but it's unknown if they got Dutch numerals. One P-40E possibly had a white "3" on the fuselage and tail. The P-40Es arrived late, but two of them may have seen combat action on the last day (March 8). There have been rumours that up to 12 extra Hurricane Mk.II and 24 extra Hurricane Mk.I have been supplied to and possibly operated by the Dutch.

Also, quoted camouflage colours for the Hawker Hurricane are somewhat speculative. The Dutch were very good in camouflaging their airfields and understood the importance of camouflaged planes. As there was time enough to give the Hurricanes Dutch national markings, I believe it is possible that at least the Dark Earth patches of the camouflage were repainted with Jongblad, which was readily available.

which is fascinating idea. Any thought's on this?

But, to answer your final question, there is no 'grey version' of RAF Sky .

It has also been reported that RAF planes for tropical use were supplied with Sky Blue undersides, not Sky.

[Nick Millman]

Intriguing reports! Leaving aside the possibilities of misperception or weathering, the only other possibility for a grey undersurface might have been if the IIBs had been delivered originally in the Day Fighter scheme (DFS) with only the upper surface Ocean Grey being re-painted in Dark Earth and the Medium Sea Grey (MSG) under surfaces being retained. So the reported upper surface colours would be interesting to know. Some IIBs were delivered to the Far East in desert colours and it was a time of expediency . . .

One of the mysterious aspects of the Dupont colour card is the absence of an equivalent to Medium Sea Grey, even though it includes Ocean Grey.

The snag with that hypothesis would be the comparison of MSG to 71-021 - a long way apart. RAF Sky Blue is closer and weathering might draw the two colours even closer in appearance. Where does the reference to 71-021 come from? From recollection or from primary documentation?

The South African artist Ron Belling conducted experiments with the weathering of Sky paints and found that the matt Sky became greyer, but that was after several months of direct exposure to the sun. However it is probably worth bearing in mind.

[Peter Boer]

Thank you Troy. The Buffalo's of the ML indeed had aluminium colour lacquer on the undersides, but the Glenn Martin

bombers had Dupont light grey (as it was called within the ML). This colour can still be seen on a wing retrieved from a swamp early 1988 in former British Borneo (now in the Nat. Military Museum in Soesterberg) and I had some paint samples

taken from it cleaned and checked against all kind of colour samples and charts. Nothing wrong with my eyesight (I still flew as a staff pilot in the RNLAF until 1995). This paint looks light grey and is very, very much like the Federal

colour standard grey 36622 of the later USAF Vietnam camouflage. The upper sides of the ML Hurricanes were certainly not repainted in any way and combat sorties of P-40Es on 8 March are impossible as these planes were based at Andir where allflying was stopped in the afternoon of 7 March already.

Peter

[Peter Boer]

Thanks Nick. The 71-021 came from an order mentioned in a memo of the Netherlands Purchasing Comm. in New York.

Weathering is possible, of course. The Hurricanes were new but assembled in the period of c. 10-15 February in the open

and flown to Kalidjati on 16 February 1942 where they were always parked in open ac pens or a dispersal area while it

was the tropical monsoon period with daily showers.

Peter

[Troy Smith]

Thank you Troy. The Buffalo's of the ML indeed had aluminium colour lacquer on the undersides, but the Glenn Martin

bombers had Dupont light grey (as it was called within the ML). This colour can still be seen on a wing retrieved from a swamp early 1988 in former British Borneo (now in the Nat. Military Museum in Soesterberg) and I had some paint samples

taken from it cleaned and checked against all kind of colour samples and charts. Nothing wrong with my eyesight (I still flew as a staff pilot in the RNLAF until 1995). This paint looks light grey and is very, very much like the Federal

colour standard grey 36622 of the later USAF Vietnam camouflage. The upper sides of the ML Hurricanes were certainly not repainted in any way and combat sorties of P-40Es on 8 March are impossible as these planes were based at Andir where allflying was stopped in the afternoon of 7 March already.

Peter

Hi Peter

I was a little distracted when writing my response, since Nick has not corrected my post it must be a reasonable accurate.

An Airforce eye test checks for correctness of colour vision, but not for close shade accuracy. this is a complex area

Nick posted this long ago

http://www.xrite.com/online-color-test-challenge

It's hard test, took me 3 goes to get 'zero' which is what you want.

A sample from a swamp after 35 years can be subject to a variety of chemical degradation and so colour shifts.

Do you know what colour was specified for the Glenn Martin bombers?

Do you have any more information on the ML-KNIL Hurricanes, or is it 'wait for the book' ?

I have to deal with dinner, sorry for short reply.

[Nick Millman]

Thanks Nick. The 71-021 came from an order mentioned in a memo of the Netherlands Purchasing Comm. in New York.

Weathering is possible, of course. The Hurricanes were new but assembled in the period of c. 10-15 February in the open

and flown to Kalidjati on 16 February 1942 where they were always parked in open ac pens or a dispersal area while it

was the tropical monsoon period with daily showers.

Peter

Thanks.

FS 36622 is a Munsell Yellow and is @ 5.95 from 71-021 where 2.0 or less equals a close match. Allowing for degradation that seems not unreasonable as applied wartime paints could and did vary from standard up to 5.

Sky to 36622 is @ 6.31 but an oxidised or weathered Sky would probably be closer and it has been noted that wartime variants of Sky were often paler than standard. The closest FS595b colour to Dupont's 71-021 chip is FS 25622 but that gives the impression of a colour that is brighter and more blueish than it really is. Recently I examined pieces of a P-40 ET589, one of 227 Curtiss Kittyhawk I delivered to the Middle East between February and October 1942, kindly sent to me by Bob Alford. It had crashed in Australia whilst with the 49th FG and was in British style camouflage. The degraded and bleached under surface paint is Munsell 4.8 GY (Green Yellow) 8.5/1.0 which is @ 4.57 to 71-021. Since the Curtiss P-40E drawings specified 71-021 for the under surface there is little doubt that the paint was intended to be an equivalent to Sky, but it was not identical.

The pigments making up the FS 595b 36622 colour are rutile titanium dioxide (a non-chalking white), yellow iron oxide, phthalocyanine blue (green shade) and natural raw umber. So you see that it is not a pure light grey by any means. Compare this with one of the known official formula for Sky of white, yellow iron oxide and Prussian blue and the potential similarities are evident. The Sky paints often used lead white pigment which could be slightly yellowish or off-white.

The Dupont 71 series were paints intended to meet British MAP requirements. All things taken together and leaving aside the description 'light grey', if the newly applied 71-021 (if that is what it was) was similar in appearance to the Hurricane under surface paint then that suggests the latter was probably Sky rather than Sky Blue which in turn suggests Hurricanes being delivered in factory TLS.

Paints of that era tended to chalk very rapidly in tropical conditions, especially if they contained large proportions of anatase titanium dioxide. The effect of chalking is to create a greyish-white patina over the paint surface that has the effect of "de-saturating" the original colour.

Sorry for the amount of potentially confusing calculation data. If you care to drop me a pm with your email address I'll send you an invitation to the blog and you can fill your boots.

[Peter Boer]

Thank you for all the info Nick. Interesting. You are right, degradation is a key word. During my research in the eighties on ML/KNIL paint schemes I used a Convair F-102 panel and a smaller skin piece of the underside of the same F-102 with Vietnam Camouflage and the latter was indeed weathered somewhat. The former ML mechanics I showed the skin pieces mostly thought the 36622 was "bang on" and very closely resembling the "light grey" of the Glenn Martin bellies, but the degradation may have helped somewhat in that opinion. Also the light grey is said to have been weathered quickly and becoming somewhat lighter in the process.

Please use my gmail adress [email protected] for further comm.

Troy the Glenn Martin colours were officially called camouflage-groen (camouflage green, a colour called light green in the order data from Dupont, first ordered in 1938 already, in fact pretty dark when new), donkergroen (dark green, a very dark colour when new) and licht grijs (light grey, also called by that name in order data and in one memo of the NPC called 71-021). For more ML Hurricane data please wait for the book.

[Nick Millman]

One further detail that might or might not be pertinent. In their study of the Fokker D.XXI Frits Gerdessen and Luuk Boerman recount a discussion between the ML Commission for Equipment and Armament and the Fokker engineer Vos in November 1937 where the camouflage colours were discussed with reference to a prepared model. The 'grey' on the camouflaged model was rejected by the Commission as being too 'cold' and instructed to be replaced by 'beige'. The authors have matched the 'beige' to FS 26360 which is Munsell 4.5 Y 6.6/1.7. The pigments for 26360 are identical to 36622 with the exception of the addition of naphthalene tetracarboxylic acid which is a beige solid making the colour more brownish.

The desire to avoid a 'cold' light grey might have similarly influenced the choice of under surface colour on the Glenn Martin.

There is a precedent for 71-021 being referred to as a 'grey'. The Bell Aircraft factory drawing # 14-976-002 for the Airacobra issued on 1/10/40 refers to DuPont 71-021 'Sky Grey paint' on the under surfaces with a note that the "Full nomenclature is Sky-Type S Grey".

Your information is intriguing in the context of the order dates for the Glenn Martin because those would appear to pre-date the introduction of Sky by the RAF. Does the Netherlands Purchasing Commission memo you referred to in post # 5 have a date?

[Peter Boer]

Right, but the beige (brown) was a colour for use in the Netherlands, also used on the Fokker T.IX bomber prototype. The belly colour for the Glenn Martins was developed in the Netherlands East Indies by the ML itself, i.e. camouflage against the background of tropical cloud formations when viewed from the ground, as was the later 36622 paint.

The NPC memo I referred to is one of a series summarising various orders from August 1940.

[Peter Boer]

Nick forgot to mention that I would love to follow your blog and fill my boots. Please use the email address I mentioned in my previous message.

Regards, Peter Boer

[Nick Millman]

Peter, thanks for the confirmation of date of the memo. Invitation sent!

Regards

Nick

[Peter Boer]

Dear all,

Further checking revealed a mistake I made some years ago. The reference to a Du Pont 71-021 order I found in a Neth. Purchasing Comm. memo from August 1940 was at the time, but wrongly, attributed to the ML/KNIL while a reference to Fuller light grey was wrongly attributed to the Dutch naval air service, MLD. The two were very likely switched i.e. the Du Pont 71-021 was actually used by the Dutch MLD for use on flying boats (including Catalina's, paint orders for which included Du Pont 71-021) and W.P. Fuller & Co 's light grey (the colour also used by the US Navy in 1940) was actually the colour used by the ML/KNIL for the Glenn Martin bomber under surfaces. The ML paint used by Hurricane mechanics at Kalidjati in Java to paint out remnants of British roundels was therefor probably Fuller light grey. As said, this ML colour almost matched the British undersurface colour on the IIBs.

Regards, Peter Boer

[JohnMacG]

Peter,

to change the sudject a bit....

when your book is published, PLEASE let us know, plus how to get a copy.

[Nick Millman]

Dear all,

Further checking revealed a mistake I made some years ago. The reference to a Du Pont 71-021 order I found in a Neth. Purchasing Comm. memo from August 1940 was at the time, but wrongly, attributed to the ML/KNIL while a reference to Fuller light grey was wrongly attributed to the Dutch naval air service, MLD. The two were very likely switched i.e. the Du Pont 71-021 was actually used by the Dutch MLD for use on flying boats (including Catalina's, paint orders for which included Du Pont 71-021) and W.P. Fuller & Co 's light grey (the colour also used by the US Navy in 1940) was actually the colour used by the ML/KNIL for the Glenn Martin bomber under surfaces. The ML paint used by Hurricane mechanics at Kalidjati in Java to paint out remnants of British roundels was therefor probably Fuller light grey. As said, this ML colour almost matched the British undersurface colour on the IIBs.

Regards, Peter Boer

Thanks very much for the further clarification Peter.

Regards

Nick

[Troy Smith]

Dear all,

Further checking revealed a mistake I made some years ago. The reference to a Du Pont 71-021 order I found in a Neth. Purchasing Comm. memo from August 1940 was at the time, but wrongly, attributed to the ML/KNIL while a reference to Fuller light grey was wrongly attributed to the Dutch naval air service, MLD. The two were very likely switched i.e. the Du Pont 71-021 was actually used by the Dutch MLD for use on flying boats (including Catalina's, paint orders for which included Du Pont 71-021) and W.P. Fuller & Co 's light grey (the colour also used by the US Navy in 1940) was actually the colour used by the ML/KNIL for the Glenn Martin bomber under surfaces. The ML paint used by Hurricane mechanics at Kalidjati in Java to paint out remnants of British roundels was therefor probably Fuller light grey. As said, this ML colour almost matched the British undersurface colour on the IIBs.

Regards, Peter Boer

This is very interesting Peter, but also changes some of the above, as USN Light Gray is never going to a match for RAF Sky, however weathered, but would be close match to RAF Medium Sea Grey I think.

This is interesting as that implies the Hurricanes had been finished in the Day Fighter Scheme, which is surprising for tropicalised planes.

Certainly later in the war DFS Hurricanes were sent to SEAC, and then had the Ocean Grey component overpainted in Dark Earth.

At this time it usually written that planes for the Far East had the Temperate Land Scheme.

Am I right in that this is the only known photo of a ML/KNIL Hurricane ?

from

http://www.network54.com/Forum/594514/thread/1295983913/Rare+KNIL+(-)+Hurricane+picture,+1942

though photos of RAF planes captured by the Japanese show pale underside more consistent with Sky or Sky Blue

http://forums.ubi.com/showthread.php/217761-Japanese-Werwolf-Hurricanes-of-the-64th-Sentai-Forums

I need to eat.

Any thought on this Nick?

[Graham Boak]

I don't think the USN light grey would be a good match for any likely RAF underside - the FAA's Sky Grey perhaps but that would have been out of use for some time by then. Medium Sea Grey is darker and too blue - it wouldn't have weathered much on the underside of what was still fairly new aircraft.

[tonyot]

Personally I would say that the underside colour was Sky Blue. I personally think that most Hurricane Mk.II`s being sent oversea`s until early 1942 had Sky Blue applied to the undersides as part of the tropicalisation process at RAF MU`s or Packing Depots, as Middle East Command had refused to receive aircraft painted with Sky undersides. Some did not receive Vokes filters as there was supposedly a shortage of these during 1941 and they were to be retrofitted while in theatre. After Japan entered the war many Hurricane`s in storage in Egypt, en route to Egypt from Takoradi or still at sea were redirected to the Far East and a batch were loaded aboard a carrier (HMS Indomitable?) on the Suez Canal and flown off to Singapore from the Indian Ocean.

The common oversea`s Hurricane Mk.IIa/b/c colour scheme during this time in early 1942 was Dark Earth/ Dark Green with Sky Blue undersides and Black (Night) spinners.

Although there is a colour `swatch' and specification for Sky Blue, my belief is that there were quite a few versions of this colour doing the rounds and that hand mixing was very common by using Roundel Blue and White to arrive at a light blue shade. I`ve never met an RAF WW2 veteran yet who knew the official names for the colours used on the aircraft, never mind what the specification was,........but I did meet one who remembered how he mixed Bosum Blue for a PR Hurri as he had written it down in his notebook, stating the weight of powder to be added to the mix,...but that is another story!

Cheers

Tony

[Graham Boak]

Sky Blue has been reported, but the problem with it as an alternative to Sky is that ME HQ thought Sky too light and Sky Blue is even lighter. It is possible that "sky blue" was just a casual observer's way of describing any light blue, and that most of them are likely to be Azure Blue - at least away from the ME and "Iraqi" Blue, or Light Mediterranean Blue. I don't really believe that most of the undersides were painted locally by front-line airmen, but at the factory or at MUs which at least had some idea what they were supposed to be. There may have been some unofficial mixes but not many, not least because they wouldn't have had the stock of paint outside of an MU. There's not a chance of this happening on a batch of some scores of fighters all heading out to the Far East.

The PR units are known to have been given a free hand in these matters.

Whichever way, it wouldn't look like the USN colour.

Edited January 19, 2015 by Graham Boak

[Peter Boer]

Yes, it does raise questions, I realise that. But..I know from several former mechanics and also several former pilots of the ML Hurricane unit 2-Vl.G.IV plus the former technical officer in charge of the assembling of the "Athene" Hurricanes in Batavia and at Kemajoran airfield that all aircraft had green and brown uppper surfaces. All were tropicalised, although the ML took the filters out of the housing to enhance speed. The ML aircraft described in detail by the former mechanics Bastiaans and Filon were Gloster built Tropicalised IIBs delivered from factory to MU in September 1941 and exported UK to Takoradi in the period Sept-Nov 1941. They were new, but, nevertheless the under surfaces were already weathered after a week of training at 2-Vl.G.IV due to the taking off and landing on wet grass surfaces (also damaging the fuselage fabric on a couple of aircraft, the water causing sizable holes).

Regards, Peter

PS Troy, the two Hurricanes on the network54 photo are Athene aircraft just assembled on a road side near Kemajoran airfield, so possibly to go to the ML but most Athene aircraft did go to the RAF.

[Nick Millman]

FWIW in a letter from the Air Member for Engineering and Maintenance RAAF, critical of the 'matt British camouflage colours' with regard to their tendency to "chalk heavily and change colour very markedly" it is stated that:-

". . . a colour like sky blue turns white within a month."

And that reference was possibly to Azure Blue. Sky Blue was even lighter to begin with. This tendency is also recorded in the Dec 1944 ICI SEAC paint report and it is worth repeating the observations here:-

"The climate is such that fading and chalking of matt camouflage colours is enormously greater than it is in the U.K. So much is this so that it makes a nonsense of carefully selected colours for camouflage schemes"

and

"Now it is unquestionably true that in Indian conditions of exposure, very marked changes in shade begin as soon as the coat (of paint) has been applied, and these changes are often as great or greater than the differences between, say, two Greys in the camouflage range."

The climate was exceptionally harsh for paint surfaces. I don't know what pigments were used for the MAP Sky Blue but I was surprised by how much white pigment and extender was included even in Dark Earth, almost certainly the reason that it so often appears lighter than expected. There is also the inevitable variance between actual paint colour standards and contract supplied applied paints.

The minute recording the RAF Far Eastern Command's preference for Sky Blue was dated 31st July and 1st August 1941 so it is just conceivable that the Hurricanes might still have had Sky under surfaces as delivered. I do have some further first hand information regarding the colour scheme on IIBs sent to Russia but I have not had time to reconcile serials and dates for those yet.

Bear in mind that the USN Light Gray was not a 'pure' grey of black and white pigments only but also contained iron oxide. Without practical experiments it would be rash to assume that the differences seen when comparing the paint standards would translate exactly to the actual weathered paint surfaces in situ.

Perception is also a factor. It is doubtful that servicemen unfamiliar with MAP terminology would identify a colour as being 'Sky' and as has been remarked here before Sky Blue is a low saturated, slightly greyish colour. An uninformed observer might be expected to describe Azure Blue as 'sky blue' and Sky Blue as a greyish blue. With consideration of the effects of climate 'light grey' is conceivable for both Sky and Sky Blue.

An Air India HQ March 1943 urgent paint request does not include Sky Blue but only Sky and Lt Med Blue, suggesting that either Sky Blue was being sourced in India or that it was being prepared by mixing as suggested by Tony.

[Peter Boer]

Thank you Nick. Most interesting comments; getting wet and drying quickly in the hot climate must have been gruelling for the paint even on under surface parts not in direct sunlight that often. The Z56xx aircraft used by the ML had a delivered MU and TOC date in September 1941 so it is likely that the main components of the aircaft were sprayed before 1 August 1941 (as the main components were brought together in final assembly at least a month before ex factory delivery and had been already painted by then). I gather that also the administrative processing of the FEC preference for Sky Blue would take some time before an Air Ministry decision reached the factories and was implemented there. I would say probably Sky under surfaces.

Peter