Green wheels in Russia

[Liobian]

Recent viewing of Russian-built aircraft - and years of related enthusiasm - prompts me to ask if anyone knows why they (and the Chinese too) seem so keen on painting wheel hubs in green ? Does the colour have some significance out there ?

[chevvron]

Way back in the '60s, they used to build them blurred; at least every photo of a Russki I saw in that era was blurred.

[barry lloyd]

Possibly for the same reason that so many lorries are painted pale blue! The paint was available (probably over-production), and it had to be used up. I doubt if there was a more logical reason for it.

[Liffy 1M]

The paint was available (probably over-production), and it had to be used up. I doubt if there was a more logical reason for it.

If there was a surplus, I doubt that using it on aircraft wheels would be a very effective way of using up stocks.

[barry lloyd]

The paint was available (probably over-production), and it had to be used up. I doubt if there was a more logical reason for it.
If there was a surplus, I doubt that using it on aircraft wheels would be a very effective way of using up stocks.

Haha! Who said it had to be effective? In a command economy you have to use the resources allocated to you, and be seen to do so, so if a couple of thousand litres of green paint are delivered to your factory, even if you didn't order it, you have to show that you have put at least some of it to good use. I have seen many dachas across the former USSR painted in a very similar shade of green

On a more serious note, it's probably just the colour of the paint which was used as additional protection against the harsh conditions of a Russian winter.

[DaveReidUK]

The conventional wisdom is that it's done nowadays purely for traditional reasons, as a nod to history, dating from the days when many wheels were produced in factories that made artillery pieces which, as we all know, are always painted green.

[dc9-32]

....and why are Russian cockpit panels blue

[crewmeal]

Must be the local vodka has something to do with it!

[Boss Raptor]

A conversation I had some years ago now with colleagues at Russian CAA (MAK);

Green wheels - primer/protective paint only, no reason to paint white albeit you can/could (red, green, whatever)

(Sicky sky blue) blue cockpits - considered after extensive psychological studies by the Russians to be the most 'restful, relaxing, focusing' colour for an aircraft cockpit (or space capsule etc.) - in fact the same cockpit colour was available as a customer option on certainly MD80's as I/we had 2 with this colour (whilst the others had the Boeing/Airbus style blue/grey or brown)

Really there is a perfectly sensible reason/answer

[DaveReidUK]

Really there is a perfectly sensible reason/answer

Except that you haven't answered the original question.

Yes, obviously wheels are painted to protect them, but why green ?

[Boss Raptor]

a lot of aircraft primer paints seem to be 'green' even in the West dont ask me why...i am sure Google can assist...chemical content??? I am not an aircraft painting specialist...zinc chromate content? or perhaps simply a 'historical' use of colour green to identify primers? - pass...

I have been told that green primer with its' chemical content 'etches' in to the metal ie. gets absorbed and is more or less permenant - u can buy white primer paint but apparently it doesnt have the same 'etching' properties...verbatim from someone here as we speak...I can comment no further/more and/or expand...trust this may help!

[Liobian]

Looks like we've run out of steam on this.
Some interesting suggestions made, so Thank You to all who bothered.

[Torque Tonight]

Except that you haven't answered the original question.
Yes, obviously wheels are painted to protect them, but why green ?

Aircraft tend to be made of aluminium.
Zinc chromate is an effective anti-corrosion primer for aluminium.
Zinc chromate itself is yellow, but add some UV inhibitors and the primer is green.
QED.

[TWT]

[DaveReidUK]

QED

Er no, not really.

Zinc chromate itself is yellow, but add some UV inhibitors and the primer is green.

Yes, primer comes in green, no argument there. But that rather begs the question of why wheels would be left painted just in primer, given the environment that they operate in.

In the absence of any firm evidence to the contrary, I'm still tending towards the artillery/tradition theory.

[Torque Tonight]

Same reason that steel girders in bridges and buildings are often red, because that is the the colour of the anti-corrosion primer for that metal, ie red oxide. Where there is no good reason to apply a different coloured cosmetic top coat, items are often left in their primer. I really think that's all there is to it.

[MrSnuggles]

Aircraft tend to be made of aluminium.
Zinc chromate is an effective anti-corrosion primer for aluminium.
Zinc chromate itself is yellow, but add some UV inhibitors and the primer is green.
QED.

True. But you don't need to add the UV inhibitors for Zinc Chromate to become green.

Chromium comes in different oxidation states, one of them is green-ish. UV inhibitant was originally black, which just made the green deeper.

One oxidation state of Cr is yellow, another one is a lovely orange-red. The oxidation state of Cr is what makes the Chromate ion change colour.

Some airplanes actually show signs of both oxidation states; using the yellow primer in some places and the green one in other places.

EDIT: The colour difference can also be due to the surface underneath. If yellow primer is applied to aircraft parts made from one alloy, or in some way treated before priming, then it would appear yellowish. If, otoh, the primer is applied to the bare metal then it would appear more green. /EDIT

Zinc Chromate primes the Al by reacting with Al to form a mixture of AlxCrOx - ZnxCrOx and ZnxOx, neither of which react with Oxygen or only very slowly with Chloride (think St Maartens environments...). Also consider that aircraft grade Aluminium often have added elements to enhance its properties which makes for an even more interesting coat chemistry.

To the first Q.... IF the wheels are indeed painted only primer green (instead of someone just coming across a great deal on green paint... known to have happened in the automotive industry in the Eastern block!) it might very well be that they save money by not painting an - in reality - "unneccessary" layer of livery paint. Your guess is as good as mine here though.

[Liobian]

Result !

Well, friends, I think I have the answer.
I recently attended the ILA show in Berlin and asked same ? of a Polish AF chap who was ground crew for their MiG29. His immediate response was that the green paint served to identify parts of an a/c which needed particular attention or caution in handling. In the case of the wheels, it was because of their magnesium content with associated fire risk. He added that the engine compartment also had some green-painted areas, for the same reason. I suppose that the dull paint would also serve to better show points of corrosion than would white or silver. Whatever, I'm convinced.