Non-Commissioned Officers rank insignia (Chevrons), U.S. Army between ca. 1942 and 1947. The Technician ranks were introduced instead of the Specialist ratings that were cramped on the ranks of Private and PFC; however were abolished in 1948 already. In 1955 several proper Specialist ranks were created. Meanwhile the Army Air Corps, which partially overlapped with the new Army Air Forces since 1942, was formally dissolved when the Air Force became a branch on its own in 1947.