Roundel of the Royal Air Force in type A1 proportions. Was used on aircraft of the United Kingdom and most British Commonwealth allies during the first half of World War Two. Yellow surround is to provide contrast with camouflage finish and was omitted when roundel used over light colours. The white ring was sometimes painted over on aircraft operating at night.
RAF Supermarine SpitfireFranks, Richard (2000)       The Avro Lancaster, Manchester and Lincoln, Bedford, UK:  SAM Publications  ISBN:  0-9533465-3-6.
Fry1989 (current code) NiD.29 (colours and proportions) Emt147 (original)