Interesting how the nuke is painted in red compared to the conventional bombings, i didn't know it was done that way. The Enola Gay also has it?
Also interesting how it did another bombrun after it dropped Fat Man.
The bomb run wouldn't be painted on until after the bombrun was complete. So that red mark can't be for an atom bomb, it has a different meaning. Same with the enola gay's markings.
It can be since the picture is probably from after the bombing (on the picture you see the nose art with the mushroomcloud and already mentionaing "Nagasaki" under the mushroomcloud. IIRC, Nagasaki wasn't the original target of the mission (i thought it was Kyoto or so, but it got canceled due to bad weather, idk) so i guess they couldn't have painted that nose art on before the bombing.
So i did some searching, and i first found some disappointments for my theory and strengthening what Theta said. I found many British and canadian bombmarkings in red among those in white, black and sometimes in yellow. Yet it was clear the red marking must have a specific meaning compared to those others since they are put in the mid of the other colors on aline, while 1 line almost always has only 1 color of bombs (black, white or yellow).
Anyway, right before giving up the search asuming Theta was 100% right in this one, i did one last googlesearch with "black for bombrun, red for firebombing" and this brought me to actually the most evident page for this question:
http://en.wikipedia.org/wiki/BockscarRight under the mainpicture, the caption says:
Bockscar nose art: the "fat man" silhouettes represent four pumpkin bomb missions (black) and the atomic bomb drop on Nagasaki (a red symbol, fourth in the line of five symbols)Of course wikipedia can be wrong. But i guess it might be right here. What i think now is that the RAF and RCAF (or maybe just every allied force on the European theatre) used red markings for firebombing missions and the americans used red for nukes only since i didn't see any other B-29 having the red markings when searching. Oh well, might be all wrong what i've written, but if someone knows more on this, please place it here, i'm really interested in this but can't find a good internetpage explaing the exact meanings of nose markings.
And other thing: i've also seen a lot of different forms of markings, i guess this is just depending on th painter, or are there differences in meaning? (apart from "planes shot down", "bombruns", "ships sunks", ...) I noticed on modern planes, the painted bombsize and form shows the weight of the bombs it dropped.
PS: sorry admins if i got too off-topic here, i considered it a discussion of the pictures posted, but if it is considered to be too off-topic, feel free to move it to the questions thread