Pilot Director Indicator for Sperry A-5 Automatic Pilot
This artifact is a WWII-era Pilot Director Indicator for the Sperry A-5 Automatic Pilot, made by AC Spark Plug division of General Mothers, part number 645262. The Pilot Director Indicator appeared on the pilot's instrument panel. The knob sets the dial to zero (at 12:00), and indicates to the pilot the desired direction, left or right, to turn the aircraft to put it on the desired course as set in the autopilot system. This unit has a serial number prefix of AF-43, evidence of a year of manufacture of 1943.
The A-5 Automatic Pilot was used primarily in WWII-era bomber aircraft of the Air Corps US Army such as the Consolidated B-24 Liberator (see photo of B-24 cockpit showing the location of the A-5 panel). The A-5 system appeared in aircraft manufactured during or before 1943, the year when the Honeywell C-1 system became the standard autopilot system for large multi-engine aircraft. Theoretically, the A-5 system may also have appeared in the Boeing B-17 Flying Fortress as well as bomber-trainer aircraft, but we've not yet found documentation to support this assumption. The A-5 was normally paired with the Sperry T-1 Bomb Sight system.
This PDI is in exceptional condition for its age and could be new old stock. Measures 3.25 inches diameter and ~5 inches deep.