Royal Air Force roundels

The air forces of the United Kingdom - the Royal Navy's Fleet Air Arm, the Army's Army Air Corps and the Royal Air Force use a roundel, a circular identification mark, painted on aircraft to identify them to other aircraft and ground forces. In one form or another, it has been used on British military aircraft from 1915 to the present.

When the First World War started in 1914 it was the habit of ground troops to fire on all aircraft, friend or foe, so that the need for some form of identification mark became evident. At first the Union Flag was painted under the wings and on the sides of the fuselage. It soon became obvious that at a distance the St George's Cross of the Union Flag was likely to be confused with the Iron Cross that was already being used to identify German aircraft. After the use of a Union Flag inside a shield was tried it was decided to follow the lead of the French who used a tricolour cockade (a roundel of red and white with a blue centre). The British reversed the colours and it became the standard marking on Royal Flying Corps aircraft from 11 December 1914, although it was well into 1915 before the new marking was used with complete consistency. The official order stated:

All aeroplanes of the RFC to be marked on the underside and on the rudder with concentric circles similar to those on the French machines but with the colours reversed, that is with a red circle inside a blue ring. The circles to be as large as possible. In addition a Union Jack 2ft x 1½ft will be painted on the wing tips outside the circles.

The Royal Naval Air Service specified in A.I.D. SK. N^o A78 a five-foot red ring with a white centre and a thin white outline on the lower surfaces of the lower wings at mid span, from October 1914 until it was decided to standardise on the RFC roundel for all British military aircraft in June 1915. With the same roundel being carried by RFC and RNAS aircraft, the use of the Union Jack was discontinued. The Royal Flying Corps and its successor the Royal Air Force have employed numerous versions of the roundel since then.

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