RAAF Boston III Aircraft

[Norman]

:popcorn: :popcorn:

[Nick Millman]

Yes, my tin of Humbrol Authentics US Medium Green is a pretty good match to RAAF Foliage Green too. What it is not a good match to is US Medium Green - popcorn notwithstanding!

Ian K Baker commented as long ago as the 1980s that Humbrol's Medium Green was too dark and indeed it is. He compared Medium Green to FS 34079 but that is still too olive. 34096 is lighter than my samples of Foliage Green but no doubt acceptable on a model - the difference calculation being approx 4.0 where 2.0 or less is a close match and up to 5.0 represents typical variance in terms of both batch and surface degradation.

The culprit for the Humbrol paint was probably the 1964 Dial IPMS chip for Medium Green which is more like RAAF Foliage Green than real Medium Green.

Medium Green is approx Munsell 1.7 G 3.0/3.0 whereas RAAF Foliage Green is in the Munsell GY family approx 2.5 GY 3/2. There is no close FS 595b equivalent to Medium Green. RAL 6028 Kiefergrün (Pine Green) is close @ 3.36 but is a little lighter and brighter. Distance of measured swatch of US Medium Green to measured samples of RAAF Foliage Green is more than 10.

Edited September 10, 2012 by Nick Millman

[gingerbob]

A bit of a tangent, but Nick, you got me to wondering: If 2.0 or less is a "close match", to what range can a "typical person" perceive a difference?

bob

[Nick Millman]

It really depends on the person and I'm not sure a "typical person" exists when it comes to colour! Most of the heated arguments between modellers are usually about perception rather than colour science and there is a real issue in the way colour is communicated within the modelling community. If you recall I posted a link here to a colour perception test which scores on the basis of being able to discern the way a colour shifts gradually from one hue to another. It is said that "most people" find it difficult to perceive a difference of 3.0 or less whilst up to 5.0 the difference can be quite subtle. A difference of not more than 5.0 is the American Architectural Manufacturers Association specification for architectural coating colour retention after 5 years (AAMA 2604) or 10 years (AAMA 2605) of exterior South Florida weathering.

I have found that up to around 5.0 also represents "typical" variance on wartime paint batches. The difference can be discerned but at the same time it is evident that the "family" of colour is the same. This is different to degradation issues where quite dramatic colour shifts can occur because of the way certain pigments age. But context is important too. Some people will be able to discern a colour difference even of less than 2.0 if the colours are examined together side by side under the same illuminant but might not be able to do so if the colours are examined separately. Many comparisons online are completely unqualified but are expected to be taken on trust, with no indication of the originator's own colour perception or the inclusion of any verifiable science as to how the determination, comparison or match has been made. A lot of hobby paint manufacturers comparison charts are made on a subjective "nearest" to sell paint rather than actual "equivalent".

There are horror stories too. Like aircraft restoration teams who have had original paint matched at the local garage without analysing or measuring it and then not preserving it when the airframe is re-painted in the new paint. They will afterwards swear that the restoration scheme is "authentic" to the original but there is no documented evidence for that or any colour science quantification of what the original colour actually was, beyond say "Dark Green". And the original paint does not survive the restoration, even as a preserved and documented sample. The discipline of archeological paint science, for want of a better term, is now well established for conventional historical study and especially in historical architectural study, but it does not seem to have penetrated into the aircraft restoration industry. Some owners of historically important artifacts resist access to them and do not allow measurements or any intrusive study of the paint chemistry yet will publish photographs and make subjective statements about their colours. Fortunately there are honourable exceptions to this and teams who have gone to great lengths to document and restore paint colour to a high level of discipline, carefully documenting everything.

Sorry for the long-winded and not entirely satisfactory reply. I should probably post some examples of colour differences but they can be found on my blogs.

[Nick Millman]

I should have added that often clearly degraded paint samples are used to illustrate colours or matches. The most common is chalked paint where the surface condition is not even recognised and the match is made to the surface deposit rather than the true underlying and original colour.

[David E]

Yes, my tin of Humbrol Authentics US Medium Green is a pretty good match to RAAF Foliage Green too. What it is not a good match to is US Medium Green - popcorn notwithstanding!

Good point sir! The one I was trying to make in my typical Grandpa Simpson style rambling was around the variability in Foliage Green, even in one WW2 aircraft plant and among well preserved paint.

Medium Green? Quite a few RAAF aircraft with "splotching" and I dare say I'll tackle a few eventually - consider me forewarned and thanks!

[gingerbob]

Thanks Nick, that's a highly satisfactory answer to me. When I finally took that on-line test you mention I did quite well, perhaps better than I expected to for the degree of care applied to it. I'm still astonished by the difference between the color sample square when you're at the store versus the look when the room's painted, though!

Quite agree that archaeological (or historical) rigor has been slow to come to the aviation world.

bob

[Seahawk]

May I thank Sydhuey, Daniel Cox and Feropete for one of the most interesting threads I've read on any forum for some time. Three people who evidently all care passionately about their subject have provided an absolute cornucopia of information derived from primary research supported by interesting photographs (not sure I knew about the 3 x 0.50" nose installation before). A classic demonstration of how the Internet facilitates the sharing of information and views both between researchers and with the rest of the world. If I knew of a magazine that carried that quality of information, I'd rush to buy it.

The later discussion on colour perception is fascinating - and alarming! - as well.

[Ed Russell]

May I thank Sydhuey, Daniel Cox and Feropete for one of the most interesting threads I've read on any forum for some time.

I'd like to second that motion - three very worthwhile contributors putting up interesting information in a civilised debate!

[Sydhuey]

Thank you all,this has developed in to a very good thread, The infomation by Nick Millman I found very interesting, having been involved in painting modern military, civilian and historic aircraft I agree colour perseption is a very individual thing and even supposed FS or other standards, until the advent of computer paint tinting I believe was only ever an approximate science, a clasic story in point was the restoration and painting of the A6M2 Zero in the Australian war memorial, it was colour matched to sample chips taken from various parts of the airframe, when painted it was a darker hue of grey than what was considered "normal" for a Zero, many experts proclaimed how wrong it was , the person who approved and justified the actual colour was Saburo Sakai himself who when he saw the aircraft(he had flown that particular aircraft on several occasions) confirmed that several Zero's in the unit were darker than the rest and he believed it was a good rendition of the aircraft colour.

[Sydhuey]

Seahawk, some of the research I've done on the "C" models I believe they were the leftovers of approx 50 A-20C's shipped out to the Pacific in mid 1943, 39 were converted to P-70A-1's and the remaining 9 given to the RAAF,I believe the 5 x .50 nose with strike camera was a hybrid conversion from the P-70 conversion program (the P-70A-1 was armed with .50's instead of 20mm).

some of the serial numbers of the approx 50 machines to ship to the Pacific;

A28-27 42-33134 A-20C

42-33135 P-70

42-33137 P-70

42-33141 P-70

A28-28 42-33142 A-20C

42-33143 P-70

42-33148 P-70

42-33152 P-70

A28-23 42-33154 A-20C

A28-24 42-33163 A-20C

42-33164 P-70

42-33165 P-70

A28-31 42-33168 A-20C

42-33170 P-70

A28-25 42-33172 A-20C

A28-30 42-33174 A-20C

42-33177 P-70

42-33179 P-70

A28-26 42-33180 A-20C

A28-29 42-33211 A-20C

42-33221 P-70

Edited September 11, 2012 by Sydhuey

[feropete]

SYD said:

"While discussing various points on the Boston with Daniel we discovered that a long held belief that early model Boston III and A-20A's with "Tropical Cowls" with the series of cooling holes in the cowls and later model A-20C's with solid cowl may in fact be the same cowls , I believed that some photo's of Australian Bostons A28-4,-16,-21 (and several photo's of Bostons captured by the Japanese sister A/C to the Australian Bostons) had solid cowls, high defenition photo's posted earlier by Daniel show these cowls actualy have panels that are fitted into the holes making the cowl look solid, why the RAAF would have some a/c with cowls with the cooling holes covered over and the rest left open is anybody's guess, severel publications on the Boston state that the earlier build Bostons had the cooling holes and as it was found that it wasn't that sucessful and went to a colid cowl on later "C's",this may be wrong but as no examples of the "C" model are preserved in the world , it is somthing we can only presume."

Hello Syd and Daniel,

I believe that early Boston IIIs and A-20As were manufactueed with the cooling vents in the cowl. These were generally delivered closed but could be opened up by the customer. It also appears that later A-20C onwards did not have the cooling vents. I suspect that this was probably to reduce the number of components in the engine cowlings and simplify manufacture.

Attached are three photos that may be of interest. I found them in a Beaufighter file at work many moons ago. Their provenance is interesting. All are stamped “DEPARTMENT OF CIVIL AVIATION” and, are quite clearly copied from A.P. 2023C, the RAF’s Boston IIIA maintenance manual. All have also been labeled as “Douglas A-20A” by person unknown. Two are marked “for Beaufort Nacelle rework”. I believe that this is an error and they probably meant Beaufighter. As we know A19-2 was converted to take R-2600 engines.

This shot is included as it shows the USAAF serial as 41-19125, (or 3), clearly identifying that photo and the one below as being an A-20C.

A shot identifying the part numbers for the various cowling panels. As stated above this an A-20C/Boston IIIA. No cooling slots in this cowling.

Another shot from the same manual, this time showing an earlier cowling with the cooling slots. It is probably another case of updating a manual, but not bothering to change drawings and photos of earlier versions, as it would have little or zero impact on the use of the manual. There is a strengthening panel on the inside of the cooling cut outs. One point of interest is the number of vents. The outer lower panels had six vents and the inner lower panel had two vents: there are no vents in the top panel. Those who have the Red Roo 1/48 scale “Tropical Cowls” will immediately note an error. Red Roo has four ‘oles too many in the inner lower panels.

I don’t believe that it was a case of some of the RAAF’s DB-73 Bostons having cooling holes and others not. Rather, I believe it is a case of none having the cooling holes initially and, then all being modified by opening up the vents. As you have pointed out, it quite apparent from photos that the apparently ‘solid’ cowlings have recesses where the cooling vents were located and, apparently, they were manufactured that way. It would appear that a plate is fixed on the backside of the vents. I suspect that this is a strengthening strip so that screws, (or rivets?), could be fitted to hold the blanking pieces we can see on the 'solid' cowls. I believe that the RAAF removed these blanking pieces when the aircraft moved up to New Guinea.

I have photos of A28-6, 16, 18, 19, 21 and 22 that show the aircraft with ‘solid’ cowls. Photos of A28-6, 21, and 22 also show them with vented cowlings.

A28-6 with ‘solid’ and vented cowling. Note that recesses where vent covers have been fitted internally are visible in first shot.

A28-22 with ‘solid’ and vented cowling. Once again note the covered vents on the bottom of the cowling in the first shot.

Cheers,

Peter M

Edited September 12, 2012 by feropete

[Sydhuey]

Thanks for that Peter , that makes it clearer and more confusing !!, I wonder why the RAAF had some a/c with closed vents and the majority with open vents, by the age of the photo's it appears that aircraft that had the vents covers had them removed with time and by the move to Goodenough in Jun/Jul 43 were all removed, going thru all my photo's of A-20A's with the 89th Bs 3 rd BG I can't find any photo's with a closed vent , also all the photo's i've seen of the DB-7B Bostons captured by the japanes all have the vent covers fitted, which would support what you said that they were delivered with vent covers and removed by the user, also I notice that the Japanese Bostons never had the gun blisters fitted to the nose , either they never got to Java with the spares package or the Japanese just never fitted them, The A-20C's the RAAF recieved as they had .50 cals instead of .303's in the cheek positions never had the blisters fitted which added to the reasons the A-20C's were faster than the DB-7B's

Edited October 12, 2018 by Sydhuey

[Nick Millman]

Thank you all,this has developed in to a very good thread, The infomation by Nick Millman I found very interesting, having been involved in painting modern military, civilian and historic aircraft I agree colour perseption is a very individual thing and even supposed FS or other standards, until the advent of computer paint tinting I believe was only ever an approximate science, a clasic story in point was the restoration and painting of the A6M2 Zero in the Australian war memorial, it was colour matched to sample chips taken from various parts of the airframe, when painted it was a darker hue of grey than what was considered "normal" for a Zero, many experts proclaimed how wrong it was , the person who approved and justified the actual colour was Saburo Sakai himself who when he saw the aircraft(he had flown that particular aircraft on several occasions) confirmed that several Zero's in the unit were darker than the rest and he believed it was a good rendition of the aircraft colour.

Sorry to prolongue this diversion from the main purpose of the thread but Zero paint is something I'm somewhat immersed in (!). There are a number of caveats to this story. Firstly the distinction between variance in paint caused by batch differences - e.g. aircraft being painted with different batches of paint showing slight variance in the paint colour - and the variance caused by degradation of the paint surface on aircraft built at different times and therefore exposed for different lengths of time. Secondly the inability of the human mind to accurately "remember" colour - at least not to a degree of precision that would be able to discern the subtleties of warm greys and grey-greens. It is almost impossible to determine between these caveats, or a combination of them, when dealing with such anecdotes.

The Zero factory paint colour was remarkably consistent in application but contained a high proportion of the anatase form of titanium dioxide - a common white pigment. This form of the pigment tended to chalk heavily, especially when exposed to an environment of high temperature and humidity (and has been largely replaced today by the rutile form which is chalk resistant). Typical exposure degradation therefore takes the original paint colour from a glossy amber tinted grey at manufacture, very similar in appearance to RAL 7034 Gelbgrau (Yellow Grey) or RLM 02, to a lighter, duller, more matt surfaced dove grey. The heavy chalking can be reduced by regular washing and surface cleaning but not eradicated. There is little doubt that a grouping of Zero aircraft manufactured and delivered at different times would show this typical degradation at different stages and therefore appear lighter and darker to the eye. A degradation model for the paint can be seen here:-

http://www.aviationo...tic-models.html

The top row of samples illustrates the typical "journey" of the paint during exposure. I know the particular restored A6M2 aircraft referred to but only from colour photographs, so I would not presume to comment on the accuracy of the paint scheme without being able to examine it first hand. But a question to be asked is whether in duplicating the "original" paint the sample chips were analysed for degradation and pigment composition or taken at their face value? The matching of degraded paint samples is prevalent, often accompanied by such assurances as "the paint was in good/original condition" or "well preserved" without any qualification of how this has been determined other than by a subjective appraisal. In the scale of things this might not be important and many (most?) will be more than satisfied with approximations. But in terms of science and especially historical record precision is important and forms the only basis by which a degree of practical latitude can be informed.

[Seahawk]

Furthermore was Sakai given a free choice of the colour in which the aircraft was to be painted or merely invited to endorse the colour already used on the restoration? Sounds to me like the latter, in which case allowance must be made for the natural tendency to agree to avoid causing offence.

[Nick Millman]

Furthermore was Sakai given a free choice of the colour in which the aircraft was to be painted or merely invited to endorse the colour already used on the restoration? Sounds to me like the latter, in which case allowance must be made for the natural tendency to agree to avoid causing offence.

A good point. The late, lamented Asahi Journal recorded that when interviewed about Zero colours by a pair of well-known researchers Sakai-san was handed a piece from A6M2 c/n 3647, a Nakajima built Zero from his unit. He licked it to make it wet and then pointed at the wet spot as being approximately the colour of his aircraft. His saliva had deepened the colour and made it glossy.

[Vanroon]

Have a look at the photo of the relic of a Japanese trainer pulled out of Lake Towada recently. http://www.japantimes.co.jp/news.html in the photo panel for 11/09/2012.

G

Edited September 12, 2012 by Vanroon

[Sydhuey]

Will just add abit about the Zero as I don't what to get away from the Bostons, Sakai saw the aircraft several years after restoration and he was the one who commented about some aircraft being a darker grey and it looked ok, he wasn't asked about it , he instigated the conversation on the differant colours.

As a foot note I overhauled the main struts and the tail wheel on that Zero restoration.

[Daniel Cox]

Hi Peter,

Thanks for posting those pics and the information on the cowlings of the "shoulder winged Beaufighter". Are you aware of any other pics of A28-4 that aren't of it pranged?

Cheers,

Daniel.

[Steven Eisenman]

Found this old article on my hard drive. I'll get arround to rescaning as a pdf.

BTW, I still have two sets of those cowlings !!!!!

[Sgt.Squarehead]

Fascinating thread guys.....So much easier to follow when you aren't quarelling with each other!

[Sydhuey]

Thanks Steven have added that article to my collection of Boston articles, I had the pictures but lost the text.

Also Peter to add to Daniels request do you have any pictures of RAAF A-20G's in flight , I have never seen one, lots of DB-7B's and C's and evan an A but none of the G's in flight.

Edited September 19, 2012 by Sydhuey

[Ed Russell]

The outer lower panels had six vents and the inner lower panel had two vents: there are no vents in the top panel. Those who have the Red Roo 1/48 scale “Tropical Cowls” will immediately note an error. Red Roo has four ‘oles too many in the inner lower panels.

You are quite right - still, it's easier to fill redundant ones than cut new ones. These are quite an old product, obviously made without the help of this nice picture. We practically sold out of them and they have been out of the Red Roo catalogue for quite some time. We are interested to know if there's much of a demand for them - if anyone is interested in them please PM me.

[feropete]

Thanks for posting those pics and the information on the cowlings of the "shoulder winged Beaufighter". Are you aware of any other pics of A28-4 that aren't of it pranged?

Cheers,Daniel.

Also Peter to add to Daniels request do you have any pictures of RAAF A-20G's in flight , I have never seen one, lots of DB-7B's and C's and evan an A but none of the G's in flight.

Daniel and Syd,

Please PM me with your email addresses and I will arrange to send you what I have on RAAF Bostons although it would appear to me that you both have somewhat more than I do.

Daniel, the only shot I have of A28-4 is a shot taken after its crash.Syd, I do have a couple of shots of Gs in flight - rather poor though - taken with the 'Box Brownie'. My shots were copied on 35mm film from the albums of the guys that were on the squadron and lack the clarity of yours, Daniel.

Ed,

not being critical of RedRoo. I only discovered the extra 'oles myself when I pulled out my Boston kits a couple of months back. Next on the bench after I finish the B-25s and Ventura. IIRC, those cowlings were one of Gary's first products, appearing some 10+ years ago. Time for a 10 year anniversary issue incorporating corrections and improvements. There appear to be at least three people here that can help with info!!

Cheers,

Peter M

[Seahawk]

Found this old article on my hard drive. I'll get arround to rescaning as a pdf.

A lot of good stuff in the old Quarter Scale Modeller, even for followers of the One True Scale. Neil Robinson: often imitated, seldom equalled. Hope he's enjoying his semi-retirement.