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Reader of this thread will be aware that I did a small thing for Polux by sending him the rudder from an old and broken model in my loft. Today I got home from a period working abroad to find a box packed with goodies from Catalonia. In an amazingly generous gesture Polux has sent me three (yes three) 1/72 kits, completely unsolicited, for me to build or ruin in my usual way I just wanted to say a public 'thank you' to Polux and that I'm looking forward to having a bash at them. I will of course keep everyone posted.
Cheers
Steve
That's a very nice gesture I always say what goes around comes around
Not very clear but there are one or two pictures here that you can see the exhaust stubs on:http://aircraftnut.blogspot.com/2014/05/back-to-ju-87-stuka-part-3-variants.html
Very interesting link!!!
I can see the exhaust and some lovely winter camouflages!!
First the stubs were made from an alloy, not a cast iron or similar, and didn't oxidise to an overall rusty look so beloved of Airfix instructions.
Secondly they were rather obviously exposed to extreme temperatures and the resulting discolouration or even burning (I remember a photograph of a Lancaster in which the stubs and part of the shroud have clearly burnt through).
Thirdly the fuel used and way in which the engine is run had an effect on the deposits inevitably coating the stubs.
Finally the exhaust stubs might be subject to some kind of specific maintenance regime, as was certainly the case for the Luftwaffe.
Add all that lot together and you can see why modellers get confused!
References are very hard to come by, particularly in colour. There are a few war birds which use WW2 fuel formulae and therefore reasonably replicate the colouration and deposits produced by their war time counterparts. I posted some pictures of a Merlin like this somewhere.
Otherwise we can make estimations. Allied fuel had a very high lead content and when engines were run lean, as in bombers trying to get maximum air miles per gallon, a very light grey/white deposit and stains were produced. When run richer, as in a fighter using maximum everything, the deposits would be darker. German fuels were made quite differently and the staining generally appears very dark. This was why black exhaust panels and other black areas were often painted behind the exhausts. The stubs themselves were also blacked.
In the factory the exhausts were finished in the regulation black with a product called Kemik Schwarz.
Initially the stubs were to be maintained with this black compound, but later simply rubbing down with engine oil became an acceptable maintenance regime.
These look black.
But it was not always the case. Exhaust stubs may not have been at the top of a hard pressed ground crew's to do list.
I still think that the original black colour is usually discernible and I always use a dark grey or metallic black as my base colour.
One question regarding material, were exhausts of all planes made of alloy?
Francesco
I don't know what alloys they all used. Rolls Royce used one of the 'Inconel' alloys (don't know which) that have a maximum of about 10% iron, hence a rusty colour is not likely. Daimler Benz also used a Nickel alloy, but I don't know its composition. I believe the Germans had problems with their Nickel supply later in the war, despite supplies from Finland, so it may well have changed. Nickel is certainly a strategic material, I remember seeing a table about it in the USSBS....might go and look it up
Here's what a Merlin 'fish tail' exhaust stub looks like when you dig it up and wash the mud off it after 70 years.
And it will clean up to something like this.
Obviously something that was iron and would rust on an aeroplane in weeks or months would not survive like this for many, many years.
I cannot post any photo of the material, yesterday a "super nova" storm left all my little village without phone line . Now I'm posting with the I-Phone
This afternoon I have gone to the city and bought the needed paints (RLM 71 and RLM 72), and tape mask..not one, two!!!
Seems tomorrow I will can return to this one again!
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