Information helpful to dating and identification US Air Force national insignia aircraft markings, commonly called "star & bars" or "roundels" that were first used by military aircraft of the United States before and during World War II.
Insignia Specification Number 241102-K
Dates used: August 19th, 1919 to May 28th, 1942
Centered red circle centered with in the star draw from the pentagon shape is commonly refereed to as "the Meatball." Colors were originally described as "old glory red" and "Old Glory Blue" or "Flag Red" and "Flag Blue" until the colors of Insignia Red and Insignia Blue were specified.
Insignia Specification Number 24102-K (Amend #3)
Dates used: May 28th, 1942 to June 29th, 1943
The star remained the same except the red dot was removed to avoid confusion with the Japanese Roundel.
Insignia Specification Number 24102-K (Amend #3)Variation with yellow outline
8th Air Force Operation Memo number 9, October 1st, 1942.
As seen in the North African Theater Operation Torch. The Yellow band would often vary in thickness. The design is inspired by the outermost ring among RAF Type A.2 & C.1 Roundels.
Insignia Specification Number AN-I-9a
Dates used: June 29th, 1943 to August 14th, 1943
Experiments showed that at a distance, shapes were more important than colors, so bars were added to the roundel with an Insignia Red outline.
Specification Number AN-1-9b
Dates used: August 14th, 1943 to January 14th, 1947
The Insignia Red outline was replaced with an Insignia Blue outline through the amendment of Army-Navy aeronautical specification AN-I-9 on 14 August 1943. This was followed by an amendment to Technical Order 07-1-1, issued on 24 September 1943, for units in the field. On some US Navy aircraft in the Pacific the blue outline was lighter than the insignia blue.
Specification Number AN-1-9b (Amend #2)
Dates used: January 14th 1947 to Present
Twin Insignia Red lengthwise bars, bisecting the formerly all-white bars, were added to the roundel in reflection of 3 flag colors, roughly nine months before the official formation of the United States Air Force on September 26th, 1947.