Turn and Bank Indicator Type A-11, AN5820-1 Air Force US Army, WWII, B-17, P-51, P-38 F-80 also very similar to the

also very similar to the ones of the N-3

An excellent overview of the system can be read at the Duxford Radio Society website

The first ~200 pages describe various aspects of air services

See photo for instructions on its use

The fluid is no longer present

Turn and Bank Indicator Type A-11, AN5820-1 Air Force US Army, WWII, B-17, P-51, P-38 F-80 also very similar to theThis Turn & Bank Indicator Army Type A 11, AN5820 1, made by Bendix Part No. 1722 2V A2, was used across virtually all aircraft of the US Army Air Force during WWII, including bombers B 17, B 24, B 25, B 26, fighters, P 38, P 39, P 40, P 47, P 51, and transports C 46 and C 47. Imprinted on the face, but barely discernible in the photos, is "AF US Army", and its serial number prefix is AF 42, indicates the manufacturing year 1942. This unit has the