Spitfire Mk i- gas sensitive paint?

[Alte Hase]

Hi guys.

I was reading through Osprey's "the legendary spitfire mk i/ii" (Aircraft of the Aces #1) and noticed a photo of a 602 squadron spitfire mk i taken in April 1940, wearing a yellow diamond shaped marking about 1ft x 1ft in size on the left wing upper surface. The caption mentions in passing that this was 'gas sensitive paint' that was there to detect poison gas.

Is this true? If so, was the use of such markings quite common in the RAF? Did many battle of britain period spits wear this marking? Was there a specific time period during which this was applied? Obviously, there are not many photos showing the upper wings of spitfires, maybe this is why I have never noticed these markings before!

Thanks guys!

 

[Airframes]

Yes, it was a gas detection patch, carried by most RAF aircraft of the period. This was because of the fear, and assumption, that Germany would possibly use poison gas on attacks on Britain, and the airfields, and was born from the use of these chemical weapons in WW1.
I haven't got the exact information to hand regarding dates, but as the threat lessened, with no known use of gas, the detection patches were eventually deleted, and newer aircraft arriving on squadrons during the later part of the BoB did not have the patch in place, whilst those which had undergone major repair and re-paint at Repair Centres likewise normally had the patch painted out.

 

[Wurger]

Yes that's true. Here you are a few examples..

However it seems that the kind of indicators wasn't painted on all planes of a squadron. I think that there was a few only for each unit in order to warn of a poison gas. It is difficult to say if the indicator was painted at the late stage of the WW2 but my reference says it was used untill the war end.

 

[Airframes]

You're right my friend. It can certainly be seen, later in the war, on 'second line' aircraft such as trainers and communications types, often on the fuselage spine, although it's use 'fell by the wayside' on most, if not all, front-line types, especially fighters.
Available photos from, for example, the BoB period, will show some aircraft with the patch, and many more without so, from a modeller's point of view, reference photos of the actual aircraft being modelled should be consulted. I admit to not adding the patch on virtually all models I've built from the BoB period, and not at all after late 1940.
However, the use of Gas Detection patches, strips and cards, was still standard on military installation buildings and other permanent structures and so on, and all RAF Stations, for example, had a Gas Precautions schedule and a small staff to administer the monitoring, throughout the war, with the carrying of gas masks being mandatory.

 

[stona]

Not forgetting that they were also applied to ground vehicles.
Cheers
Steve

 

[Edgar Brooks]

The patches were, in fact, sheets of paper, painted with the chemicals; if you look closely at photos, it's sometimes possible to see the strips of tape holding them in place. They were supposed to turn red in the event of being exposed to gas, but Guy Gibson wrote that, when tested, many failed, which is probably why their use fell away; production ceased in 1943. The Americans had a paint, which was daubed on their vehicles, but that does not seem to have pertained to their aircraft.

 

[Raptorattacker]

US aircraft? Oh yes they did... sorry about being 'a bit late' but there you go!

 

[Crimea_River]

What's the point of painting the patch where the pilot can't see it?

 

[WARSPITER]

What's the point of painting the patch where the pilot can't see it?

True. And if it's behind him and he's had baked beans at breakfast he could set it off.

 

[pbehn]

What's the point of painting the patch where the pilot can't see it?

You could make the same point about one on the wing, whats the point of putting it where you have to climb on the wing to see it?

 

[stona]

The patches were not applied for the pilot to see. They were applied for the ground crews to see. You would not have to climb onto a Spitfire wing to see the patch, unless you were severely vertically challenged.

Aircraft were not likely to be contaminated whilst flying, they would be contaminated by a chemical attack on the airfields where they were parked and dispersed. All the chemical agents available for potential use at this time were intended to stay close to the ground for what I would have thought were obvious reasons. Several of the agents were very good at rolling into trenches, gun emplacements, dug outs, etc. where the contamination lingered.

The patches or paints were also applied to ground vehicles, buildings, lamp posts, dust bin lids, and just about anything else where they might reveal contamination.

If an aircraft was shown to have been contaminated it would require decontamination (basically a good wash) before it could return to operations.