Heading Selector, Zero Reader
The Zero Reader Heading Selector, made by Sperry part number 672670-2, was a component of the Zero Reader Flight Computer. The Zero Reader was used in a number of Cold War era aircraft of the US Air Force, such as the F-89 Scorpion and F-94 Starfire jet fighters/interceptors (see photos from F-89 flight manual showing the location of this instrument).
According to the F-94 Starfire Flight Manual:
The Zero Reader is an automatic flight instrument that combines all of the information required to fly the airplane on a predetermined flight plan in a safe manner, and presents it to the pilot visually on the Zero Reader Indicator. The Zero Reader may be used for instrument flying or for making instrument approaches. When it is being used, the other flight instruments need only be used for reference. Briefly stated, the Zero Reader can be compared to an auto pilot in which the human pilot replaces the servos, since all that is required of him is the proper response to its indicators without the necessity of making any mental computations.
The artifact is in exceptional condition given its age. The knob turns the heading selector pointer (the wide, dual arrow) freely. Measures 3.25 inches diameter and ~7 inches deep.