Camouflage paint on Fw 200-C aircraft - Not RLM 72+73 on earlier examples

[INM@RLM]

This FoWu instruction has just turned up in a new treasure trove of 470-odd Focke-Wulf internal documents found amongst the microfilmed T2 archives from Wright-Patterson. The finder of this series of documents most generously allowed them to be shared with me.

The document is dated Bremen, den 26.7.40 and the key statements are:
Nachtrag zu Kom. 21 08 016
Muster: Fw 200 C-2
Auftraggeber: RLM
Kostenträger: RLM
Termin: Mit den Arbeiten ist sofort zu beginnen.
Betr.: Sichtschutzanstrich an Fw 200-C Flugzeuge.
Erfassung der Kosten für folgende Arbeiten:
1.) Ab Werk-Nr. 0024 is der Sichtschutzanstrich im Farbton 72+73 dürchzuführen.
2.) Auf dem blauen Lack der Unterseite ist ab Werk-Nr. 0022 der Isolierlack S 238 der Fa.Ruth aufzubringen.
Für weitere Werk-Nr. sind die jeweilligen Bau-Kommissionen zu belastung.

In other words:
Re: Camouflage paint on Fw 200-C aircraft.
Addition of the costs for the following work:
1.) From (and including) Werk-Nr. 0024 camouflage paint 72+73 is to be introduced. [WNr. 0024 happens to be the fifth and final example of the Fw 200 C-2 sub-type.]
2.) Regarding the blue finish for the underside, from (and including) Werk-Nr. 0022 Isolierlack S 238 manufactured by the Ruth company is to be used.
For succeeding Werk-Nummern the relevant Bau-Kommissionen (works orders) are to be charged.

The clear inference then is that the RLM 72+73 finish was not applied to all Fw 200s delivered prior to WNr. 0024. In short, at least some of these aircraft, and probably all prior to WNr. 0024, were likely supplied with upper surfaces finished in RLM 70+71.
[WNr. 0024 happens to be the sixth and final example of the Fw 200 C-2 sub-type, whilst WNr. 0022 was the fourth such example. The next aircraft, WNr. 0025, was the Fw 200 V-13 and the Musterflugzeug for the Fw 200 C-3 series.]

That the finish applied to the earlier Fw 200 Cs was not RLM 72+73 does fit more logically with the sequence of events. There was no persuasive reason why Fw 200 C, WNr. 0001, of Rowehl's VfH, should be camouflaged in a scheme distinctly different to the He 111s being assigned to the same unit in the same period. Nor why a long range bomber and recce unit, formed in the winter of 1939/40, should have been camouflaged differently to the Luftwaffe's other land-based recce and bomber aircraft of this period. It appears that only after the Biscay bases of western France became available in July 1940 did it become clear that Fw 200 C operations would now be largely maritime in nature.

So, at least for the earlier examples, Jerry Scutts (Fw 200, 2008, p.217) seems correct in his contention that the Military Condors were finished with RLM70+71 upper surfaces, rather than RLM72+73. However, we now have a documented dividing line between those and the RLM72+73 finish that has been almost universally assumed to have applied to all Fw 200s in the WNr. sequence that began with 0001.

It would be interesting to gain some understanding of why Isolierlack S 238 der Fa.Ruth might have been selected exclusively for the underside finish, and why this change was made ahead of that for the upper surface colours.

In this document series the significant documents are all headed Auftrags-Anforderung. These appear to be the control documents used to formally authorize the commencement of work within the FoWu company on a specific change request received from a customer. Many of these documents relate to very mundane changes. There can also be multiple copies of a single document when the initials of those required to confirm they have seen it have had to be gathered on different copies.
The great majority are dated before 1943 and understandably, most seem to come from the 1939/40 period. Accordingly many questions from the Fw 200 sequence after WNr. 0200 remain unaddressed, but a mass of rich detail is added regarding what changes were applied and when to the surviving prototypes, and early sub-types: A-0, C-1, C-2, C-3, C-4, D-1 & D-2.

As a sidebar, to my mind there is a clear need for a software tool which would allow direct comparison of the different shades in selected areas of the same photograph. Where that photo has already been digitized it would be a straight forward matter of reading the tone values direct from the existing data and displaying the absolute and percentage values of contrast on screen. For images not already scanned the simplest solution would be to photograph the image with a smartphone and then use the software tool to select the areas for comparison, saving these selections in a copy of the photograph, along with the resulting table of contrast values.
For photos taken in similar light conditions it would be reasonable to expect that similar values of relative contrast would be found. In short such a tool would start to bring some precision to the task of distinguishing between 72+73 and 70+71, or between 02+71 and 74+75, especially when there are other comparison photos taken in similar light conditions with less doubt about the colour tones used.

Perhaps such a tool already exists? If not, hopefully soon.

[INM@RLM]

PS This is the sole document in this T2 collection dealing with Fw 200 paint finishes.

[Adriano Baumgartner]

Uoooouuuuuuuuu incredible finding!

Hope you will dig much more material related to LW paint schemes. Thanks for sharing this with others. Most welcomed for modellists and Historians alike.

Surely, a tool to find the correct tones of RLM colours on black and white (or magenta) images would be most welcomed by most of us....the market is open for the specialists on this field to develop such a tool for Historians (sprog and professionals).

Congratulations and thanks again for sharing this information.

A.

[Adriano Baumgartner]

There is another entry for this product (Isolierlack S 238) here: http://www.wwiiaircraftperformance.o...42-german.html

Translation:
After completion, top bottom with insulating varnish S 238 Farbennersteller (Warneke and Böhm)

I contacted them (https://www.wb-coatings.de/kontakt-en-gb/) can give us a glimpse of what it was (seems to be some kind of insulating varnish to preserve corrosion by sea water or intemperies?)

Am not a painting specialist but would like to know how it worked and how it was applied over the airplanes.

NICE THREAD by the WAY! Congratulations

A.

[Nick Beale]

That should be Farbenhersteller with an “h” in the middle = paint manufacturer.

[ChrisMAg2]

Originally Posted by Adriano Baumgartner

...
Translation:
After completion, top bottom with insulating varnish S 238 Farbennersteller (Warneke and Böhm)

...

Forgive me for being picky, but this is a wrong translation. It should be isolating. This lacquer has nothing to do with temperature control, instead it isolates (protects/ shields) an underlaying surface from something else (e.g. enviroment).

[INM@RLM]

Thank you for that very good spot, Adriano. Both of the following comments are also spot-on to my mind.

That Bf 109 G-2 application deepens the mystery though. We now have two unrelated mentions of what is probably precisely the same protective lacquer (to get very exact, in one place it is described as Isolierlack S 238, in the other it is Isolierlack IS 238), but in neither place is it associated with a specific Fliegerlack-Nummer. For the Fw 200 C the coating is tinted with RLM 65, but on the Bf 109 G-2 it appears to be a clear finish applied to the whole aircraft after both undersurfaces and upper surfaces have already been camouflaged. ("Nach Fertigstellung oben und unten mit Isolierlack IS 238.")

The lacquer recipe is confirmed as belonging to Warnecke & Böhm in the Bf 109 G-2 mention, but Firma Ruth was an acknowledged licensee of Warnecke & Böhm. (Explicitly confirmed in the Fz. Handbuch for the BV 138; Teil 0, Anlage 2 Oberflächenschutzliste, Seite 1.) If we take that section as our guide, Ruth seems to have specialized in production of the smaller-run Wu.B lacquers including those applied to metal surfaces for use in maritime environments.

The same page of the BV 138 Oberflächenschutzliste includes a useful table setting out the earlier company designation for each lacquer used on the 138 with the subsequent Fliegerlack-Nr. Yet there is no mention here of an Isolierlack nor of any Wu.B formulation numbered 238. (Although there is mention of a Wu.B 138 subsequently designated as Fl. 7118.) I've also checked through the 1942 and 1944 editions of Die Flugzeugmaler and found no mentions of an Isolierlack, even in the four-page 1944 reference table of previous designations and subsequent Fliegerlack Nummern.

It will be most interesting to see what this thread turns up, but from the lacquer name it does sound as though we are dealing with a finish conferring specially enhanced sealing properties, hence more expensive and apparently too specialized to have ever been assigned its own Fl.Nr.

As to why this finish might be used on a Fw 200 C but not a BV 138, the later was genuinely an all-metal aircraft.

We are conditioned to think of the Fw 200 as the first recognizably modern four-engine air liner and this is indeed one part of the truth. However, structurally the Fw 200 was the last of an older order of designs with wings outboard of the engines from the main spar to the trailing edge being covered in linen fabric. Thus although it has been claimed outright that the Fw 200 was "das erste viermotorige Langstreckenflugzeug der Welt in Ganzmetallbauweise", this is not technically accurate, and FoWu themselves at the time classed the design as of mixed construction (Gemischtbauweise).
Hence a possible justification for the use of Isolierlack S 238 on the undersides of the Fw 200 C was to seal all undersurfaces, most particularly the very large fabric-covered areas of the outer wings, to ensure that despite wet runways and low-flying over the sea in all Biscay weathers, the fabric-covered portions of the undersurfaces, most exposed to water spray of all sorts, would not become water-logged and begin to rot.

[INM@RLM]

Actually, when I recheck the aircraft handbook (Fw 200 C-1 und C-2, D(Luft)T 2661/1, Flugzeug-Handbuch, 1940), Focke-Wulf were not quite as forthright as this. Their own wording was "Das Flugzeugmuster Fw 200 C ist ein Landflugzeug in der Ausführung eines freitragenden Tiefdeckers in Leichtmetallbauweise".
So a cantilever low-wing aircraft of light metal construction, which is entirely accurate as to the internal structure. But FoWu at the time never claimed that their aircraft was of all-metal construction; that is an embroidery stitched on by post-war writers.

The wing structure is described in this manual as:
"Das Flügelmittelstück trägt den Rumpf, die vier Treibwerke, das Fahrwerk und vier Landeklappen und Kraftstoffbehälter. Die Beplankung ist aus Duralblech hergestellt und vor dem Holm begehbar.
Die Aussenflügel haben im Aufbau dieselbe verdrehseste Haltenform, sind hinter dem Hauptholm zum Teil mit Stoff bespannt und tragen je eine Landeklappe und zwei Querruder."
and even more explicitly a few paragraphs further on:
"Beim Aussenflügel ist der Aufbau ähnlich wie beim Flügelmittelstück, jedoch ist der Aussenflügel hinter dem Hauptholm zum grössten Teil mit Stoff bespannt.”

With acknowledgement in part to Google Translate: "The wing center section carries the fuselage, the four engines, the landing gear and four landing flaps and fuel tanks. The panelling is made of dural sheet and can be walked on in front of the spar.
The structure of the outer wings has the same twisted(?) form, they are partly covered with fabric behind the main spar and each has a landing flap and two ailerons."
and
"The structure of the outer wing is similar to that of the wing center section, but the outer wing behind the main spar is mostly covered with fabric. "

[Graham Boak]

For "twisted form" read "section profile". It would otherwise make for a very awkward transition... but of course two different section could be smoothed out over a fairly short distance.

[INM@RLM]

Thank you, Graham.