Re: RLM 81/82 – More secrets unveiled
 

Hola Folks,
just return from a business trip and read all the comments regarding my postings Hornets Nest and RLM 81/82. Sitting in Front of my computer and I am amazed about that what I read. Maybe now I am again and usual the typical "ugly" German, but my statement to the discussion is:

• I am amazed that this discussion absolutely lacked basic knowledge from well published original paper work about RLM-paints and lacquers!

Yes, we haven’t the whole picture, but we have enough for a rough picture. With my discovered facts the history of RLM 81/82 and 83 must be rewritten!


Facts (My quotations are for my second edition Hikoki book)

• RLM 81/82 introduced for replacement of RLM 70/71. Yes, enough evidences.
  “Nachdunkeln” is the original statement in the text. I also have no better explanation for this, but consider that all RLM-paints, - lacquers and so on are artificial resin lacquers. A technology just invented. Today no one is in the position to make any statement about the behavior of the paint during longer use!!
• RLM 81/82 as replacement for RLM 74/75.
  Document not discovered yet!
  Maybe in Sammelmitteilung 2 under camouflage (page 346) we have more than a hint. Maybe this camouflage guide was the source? But I am pretty sure that this short statement was the source for the mystery of Darkgreen (former RLM 83)/75 camouflage, because the statement was, that RLM 74 discontinued. Today, with my discovered documents the sentence has a different sense: RLM 74/75 was replaced with RLM 81/82, therefore 74 was discontinued, but RLM 75 was used for Nightfighters! Understand everyone this different sense? The discovered documents contain a lot of this missing links.
• The variation of RLM 81/82. Sammelmitteilung 1 (page 343) RLM QA received no color charts, therefor no acceptance inspection of the paint’s shade. This is a fact that RLM had published!!
  The discovery of the paints in Czech Republic mentioned on the JaPo home page support this. I read the label as RLM 81 and it contain a “Darkgreen Paint”.
  This Green/green camouflages (sometimes mentioned as 81/81 camouflage) is nothing more nothing less than a 70/81, 81/70 combination for using up old paint stocks with a, maybe Darkgreen shade of RLM 81 (Page 344, application of color shades 81 and 82, and Do 335 documents, page 268)

I don’ want to be rude or so, when I wrote that the discussion lacked knowledge, but without these basics understanding every discussion is senseless! And the basics are published since years! First you have to read, then to understand and then to discuss!
Again for me now a lot more makes sense. I hope I will discover more documents in the future to bring more light into this darkness.
Looking forward to read your replies.
Best Regards from Germany

Re: RLM 81/82 – More secrets unveiled
 

As I understand it, RLM lacquers that reached basic approval stage were then tested for tensile strength and fade qualities after 6 month exposure to weather and sunlight, and had to meet a minimum requirment of 2 year life span in open air conditions or 1500 flying hours. 5 years being set as realistic maximum. Paint care products were used, and a single application had to last for 100 takeoffs or 2 months of bad weather operations. The end results was a very high quality finish.

I am an automotive painter, going on 25 years now. I worked with lacquers, acrylics, polyurethane, enamels, everything. I never seen paint darken due to the environment. The only way I can see if there is a chemical reaction somehow. But even that, would show right away.

I'm not saying I know the answer, but I'm not convinced of a darkening effect on paint in outside environments. Maybe 71 was lightening(?).

Re: RLM 81/82 – More secrets unveiled
 

Oberst, read posts 11 and 12, there seems to have been trouble with 70/71 and quality. The info in my post comes from Jürgen Kiroff, written in an appendix to Ken Merricks two volume work on Luftwaffe camouflage. In post 12 there's a good example of what have been the reason for the paint darkening.

Even if there was an unlikely typo or misunderstanding in the document as to how the quality of 70/71 was bad it doesn't make the document less valid does it?

I agree that it's surprising that such paint passed the rigorous quality control of the RLM, was there a change in the formula that created unforseen troubles I wonder?


Cheers / Anders

Re: RLM 81/82 – More secrets unveiled
 

Could the term 'Nachdunkeln' when used in this sense be translated as 'dulling [=de-saturation]' (with time)? Fading...? or 'mattes' over time?

Re: RLM 81/82 – More secrets unveiled
 

I agree that the basic translation of "darkening" doesn't really fit what you would expect (i.e. colours usually fade) and maybe there is another sense of the word, or the wrong word was used (human error is always a possibility).

On another point, what earthly use was paint that lasted years on a combat aircraft that would be lucky to last weeks? This sounds like a peacetime standard which may of course not have been adapted to suit wartime conditions; once something is in a book of regulations it can be hard to change.

Re: RLM 81/82 – More secrets unveiled
 

Hi Michael,

I totally agree with your post #21 ... that's the reason I opened your Hikoki book where I did find this extract Under!
Enjoy it.

Regards, Franck.

Re: RLM 81/82 – More secrets unveiled
 

In post #12 I wanted to explain this effect "nachdunkeln". Some yellow pigments are not stable according to my experiences. In case a colour loses its yellow portion through dissolution of those pigments it inevitably will change its general character.
A simple example: In case of green lossing its yellow portion it will change towards blue.
The Ju88 fuselages in Berlin wear a "RLM 70/71" camouflage which can be described as two greys with a slight greenish touch. The colour has NOT faded, it looks darker.
And this might be the effect of "nachdunkeln" which is described in the official paper.
Michael Ullmann, from memory some "chromium" pigments come to my mind. Can the pigment be named exactly which has caused this colour shift? Isn´t it possible the ominous brown-green is nothing more than an attempt to create more stable greens by adding yellowish-brown pigments?

Servus

Roland

Re: RLM 81/82 – More secrets unveiled
 

Hi!

Interesting...

The JG54 green cam job in 1942/1943 was not done with a "new" German spec paint -it was a RUSSIAN spec.

The green color used on the Russian front, was John Deere Green.

Yes, that is correct.

The Russians had bought numerous supplies of tractors and military equipment manufactured by John Deere FROM the US. They were also supplied with the correct paint (John Deere Green).

Repairs and cam jobs DONE in Russia, were completed with RUSSIAN technology. This is why we find IMPERIAL (not metric) screws and fitting on repair jobs on German wrecks found in Russia.

The Germans were not using RLM spec colors - they were using what was on hand in Russia. In this case, captured Russian materials and paints.

John Deere Green is the exact color that was found on the Fw190 that is with the Flying Heritage collection and is now flying. It is also the exact paint they used when painting her during the restoration.

So these early aircraft were not using a "new" paint - just what was on hand at the time - in this case, John Deere Green...

Mike

Re: RLM 81/82 – More secrets unveiled
 

It may have been a close colour match, but you do not use tractor paint on aircraft! This is an old and totally discounted tale. Aircraft paint is different from other paints, a speciality in itself because of the specific requirements for adhesion to light metals under a wide range of conditions (pressure and temperature), light weight and low pigment size (for low drag). None of which apply to tractor paint other than temperature to a more limited extent. If the paint was of low quality then this affected the performance of the aircraft - top speed and maximum altitude reduced, fuel consumption increased.

Anyone who tells you that car paint, tractor paint, ship paint or household emulsions were used on aircraft (other than for decoration on a limited area) does not know his subject. There were very specific regulations about the application of paint, with inspectors making sure they were kept to. The Luftwaffe was no less strict on these matters than any other nation.

Re: RLM 81/82 – More secrets unveiled
 

Graham, you need to move beyond that, because what ever paint was at hand may have had to do. USAAF used Corps of Engineer sand in the Pacific. After reading the monograph on Malta Spitfires, some of those aircraft wore as much as four coats of paint.

And there is no real evidence that aircraft on Wasp were painted in aircraft paint.

Sometimes the need for proper camou trumps the 6mph or so of lost speed.

As for tractor paint, I've never seen anyone present anything but rumor. The Germans overran VVS airfields, I'm sure there was some paint about.