the lancaster kicks ass said:
again it comes down to type of aircraft and when/where they flew, Bomber Command used the B-type roundel on the upper surfaces as it was harder to spot, and thus incresed it's chances of not being spotted at evening/early morning, and none were worn underneath because they were easily spotted by spotlights, fighter command however aften prefered roundels with white in and even the yellow border because in the heat of combat it was easier to spot the white and yellow parts so you don't end up shooting your own guys, and cammo has a lesser part to play in fighter operations, and fin flashes traditionally match the fusilage roundels, if you have a large white section in your side roundel, you have a large central white stripe in the fin flash, small white area=small stripe in fin flash, as for positioning they always tried to get them in the traditional 6 locations (one either side of mid/rear fusilage, one on each upper outside wing and one on each lower outside wing) unless the mission profiles meant it was best to do something different (as in BC not using lower roundels at night) or the plane was unusual and couldn't have them in the normal places..........