Ball Turret Azimuth Position Indicator, B-17, B-24 B-29 the calculator measures ~8 inches

the calculator measures ~8 inches by 6 inches by 1/2 inch thick

part number 1470-8-02 (FSS# R88-A-140-15) as made for the US Navy's fighter aircraft F4U-5N (and -5P and -5NL) Corsair

but not guaranteed

The E-4 System was used in the late 1940-1950's and was still in use in some 1960's aircraft

It is presumed to be a WWII-era indicator used in aircraft of the Japanese Army or Navy

Ball Turret Azimuth Position Indicator, B-17, B-24 B-29 the calculator measures ~8 inchesThis is a mechanical Ball Turret Position Azimuth Position Indicator, Sperti part number 11585, used in the Sperry ball turret in WWII era heavy bombers such as the B 17 Flying Fortress and B 24 Liberator. Mounted within the ball turret at the right foot of the ball turret gunner (see photo), it was connected to a rotating mechanical control cable. The round turret silhouette in the center of the dial rotated as the turret rotated relative to the