Aluminium and grey noses in British aircraft

[Romani]

Here is a little observation and reflection that I thought maybe is of interest to some.

It has always struck me as odd that the engine cowlings of many British airplanes were left in natural metal, wich in all likelihood not as gleaming as the examples existing in museum, would glare so obviously, (or should it be glaring obvious?) that it kinda defeats the purpose of camouflaging the airplane in PC10 color.

Then after reading about PC10, it seems that the reason was to save paint, the supply of pigment was insufficient, so cowlings were painted natural metal, or battleship grey paint was used. Same reason why wooden struts and undercarriage legs (like in the SE5a) were simply varnished.

But what about the glare or the contrast of the light grey paint with the dark khaki paint? It seems now that it was considered an acceptable risk. Since the nose of the aircraft would be usually obscured by the top wing when seen from above and behind. So in the worst possible circumstance, with an enemy high on your six and with the sun on its back, he would not be in a position to observe the glare on the unpainted nose since from that angle is hidden from view by the top wing.

But there's an exception to this rule: the SE5a, one wonders why the nose was always painted in PC10, even in the underside. It didn't make sense when paint shortages left the struts unpainted.

Then one day I was looking at photos of WWII Mustangs and I realized it, these were left unpainted, but the cowling on front of the engine was painted to prevent glare from blinding the pilot.

With the long nose of the SE5a, I guess same thing happened, same solution applied. Also, the nose was longer than in a Camel, for example, so it was not completely obscured by the top wing.

The more I read about WWI aviation, the more I marvel at how clever were the people that designed and built these airplanes!

[Colin A Owers]

Protective Coverings (PC) were developed to prevent the sun's rays leading to the fabric deteroriating. They were not used as camouflage as such. The camouflage effect was a byproduct of the colouring. P.C.10 was khaki and P.C.12 was red brown. They were used after the war as a coat under the V.84 aluminium finish.

As to the reason for S.E.5a cowls and grey panels, I don't know of an official explanation.

Colin A Owers

[Sreiko]

Everything need some kind of protection so it is also used on metal. Metal color on British aircrat look like the later color Dark Admiral Grey. The same PC.10 is shaded to match ground infantry uniforms, Cellon director W.J. Shilcock:

"We were all so used to seeing all War Office equipment in field green, or khaki drab, that we quote naturally visualised Army aircraft being in similar sort of colours and far no other reason then that".

Hope this help

[Dan_San_Abbott]

Romani;
Dope was on the shortage list in Germany, England and France. to my knowledge, Oil based paint was not on the shortage list in England and France. Metal cowling were painted with oil based paint by all three countries.
Blue skies,
Dan-San

[Dan_San_Abbott]

Colin Owers:
You could do me a favor, could you explain what color khaki is?
Blue skies,
Dan-San

[brisfitworks]

Romani:

Interesting thought.

My interests always brings me back the Bristol Fighter - long nose and thus subject to the glare idea you described. It was typically painted grey on the metal work. (F2a's appear darker and likely a PC10 match then).

So why grey vs a PC10 like colour as the RAF did with the SE5? Preference or opinion? I am interested in the real answer; there can be volumes of conjecture.

As to Camouflage considerations ...
My father was an officer in the Cdn Army and did a lot of training. He taught me about the five S's of camouflage: Shape, Shine, Silhouette, Shadow and Sound. All these must be surpressed.

By these theories, the contrast of a grey nose is like dazzle patterns - a break up of the silhouette and thus more consistent with the concept though not great since the wings and fuselage are the strongest sihouette components.

Sreiko: Mr. Shilcock's quote is so very typical of the real reasons behind decisions - becasue that is what we are used to!

Dan San Abbott:
Thank-you! oil based on metals and shortages of dope base. An obvious thing but that explanation is enlightening.

Originally Posted by Romani

...
It has always struck me as odd that the engine cowlings of many British airplanes were left in natural metal, .....

Then after reading about PC10, it seems that the reason was to save paint, the supply of pigment was insufficient, so cowlings were painted natural metal, or battleship grey paint was used. ...

But what about the glare or the contrast of the light grey paint with the dark khaki paint? It seems now that it was considered an acceptable risk. ....

But there's an exception to this rule: the SE5a, one wonders why the nose was always painted in PC10, ...

... photos of WWII Mustangs and I realized it, these were left unpainted, but the cowling on front of the engine was painted to prevent glare from blinding the pilot.

With the long nose of the SE5a, I guess same thing happened, same solution applied. Also, the nose was longer than in a Camel, for example, so it was not completely obscured by the top wing.

[NeilE]

As others have pointed, PC-10 was not camouflage colour, it was a protective covering.

Cowlings/engine covers were not always painted grey or left in bare metal (rarer). There was considerable variation, if you look through photographs you'll see that. My take on why the grey paint was that it was most likely used because, simply, it stood up to the heat generated by engines better.

Also Struts generally weren't painted because it added to the drag factor.

[Romani]

Originally Posted by NeilE

As others have pointed, PC-10 was not camouflage colour, it was a protective covering.

Protective coating was the main consideration, but not the only one. If only sun protection was desired, there were other choices like aluminium finish, white, or black.

From the appendix on Munson book by Ian Huntley page 182 (highlight is mine)

"The Protective Covering studies were prt of a series of experiments, started in early 1914, to find an ideal pigmentation that could be applied over clear-doped aeroplane fabric to shield it from the rapid rotting caused by the injurious (ultra violet9 rays of the sun. Most succesful of the original P.C. series was P.C. 10, then descirbed as a dark khaki varnish, wich afforded not only protection from the sun in a temperate climate but also a degree of camoflauge when seen from above."

It might well be that Sreiko anecdote is true, that of the coatings tried they went along with khaki out of inertia because Army stuff was khaki already.

Cowlings/engine covers were not always painted grey or left in bare metal (rarer). There was considerable variation, if you look through photographs you'll see that.

thank you, but I already know that. I know the reasons why they had to paint the cowlings in another color. I wondered at the SE5a exception, and it puzzled me that the effect made the aircraft more visible. I think I answered those two questions in the original post.

What forced British manufacturers to leave cowlings unpainted or painted in gray? DSA points out it was because pigmented oil varnishes (POV)save on cellulose. Correct but not the complete answer. There were three clases of doping/finishing schemes, class B (latter 1917) and class C (1918) finished saved cellulose but recquired much more pigment, solvents and softeners.

During the early part of 1918, as Class B and C finishes called for greater quantities of basic pigment materials, a shortage of P.C. 10 led to a use of a dark grey POV or other shades of grey as an alternative

My take on why the grey paint was that it was most likely used because, simply, it stood up to the heat generated by engines better.

That's very interesting and would explain why Germans painted their engine cowlings sometimes in grey.

Also Struts generally weren't painted because it added to the drag factor.

Very interesting also, but does really a POV (oil varnish + pigment) produce a more rough finish than plain varnish on top of wood? Cabane struts in Nieuport 17 were painted in aluminium while interplane strus were plain varnished.

German airplanes used to paint their struts, but a lot of the time they were metallic, so paint was a must to prevent rust. If it indeed causes more drag, then the question arises, how much? It was significant?

*rant on*
EDIT: By the way, I feel that I was ripped off with the Osprey volume on Sopwith Camel aces, I loathe the glossy finish of the paper and the computer coloring, because it's so hard to tell apart when the cowlings are finished in grey or natural metal (this goes too for other volumes) I know computer coloring is unavoidable in order to keep pumping out books, and old illustrations with color pencils, oils or airbrush are a thing of the past, but I wish the artist made more marked the difference, or the captions include notes. Else, an unwary modeler can look a profile 13 (MacLaren) and believe the turtledeck is metallic isntead of wood!

I also loathe the cheap gimmick of adding sun glares to the shiny spots, and the shadow of the upper wing, I would forego all those useless computer effects for clear paintings with no distortion. For example, if I hadn't that reference, and bothered to consult it often, I coudn't tell if the plywood panels are painted in the same PC10 tone as the fabric and they look a shade lighter because it's a more reflective surface, or indeed they were painted in a slightly different color, as it could be the case.

Coupled this with the screwup with the blue color in roundels, and the fact that color profiles are one of their selling points, and I feel ripped off

*rant mode off*

[Colin A Owers]

I agree with the criticism of the use of colour profiles without a caption stating the colours. It is too easy for the colours to be too close to one another for old eyes like mine to distinguish the difference. Also most colours are only educated guesses as to tone, so a written description of the assumptions made in creating the profile would be most welcome.

Colin A Owers

[Pips]

Originally Posted by NeilE

My take on why the grey paint was that it was most likely used because, simply, it stood up to the heat generated by engines better.

You have probably touched on something there Neil. Gray paint would have been readily available and in plentiful supply, given the need for the Navy to keep ships of the Grand Fleet in tip top condition. It would have been eminently suitable for application to metal, and durable to boot.