Directional Gyro Control, US Air Force Type E-4 Autopilot/A-12 Gyrosyn, 673447
Here is a Directional Gyro Control of the Sperry A-12/Gyrosyn Automatic Pilot, known in the US Air Force as the Type E-4 autopilot system during the late 1940's and 1950's. The USAF type is S3A, and the Sperry part number is 673447.
When electrically powered and in-flight, the gyro produced directional indication signals which were amplified and transmitted to the autopilot system and indicators on the flight deck of the aircraft.
The cover can be removed to reveal the gyro inside. The gyro has apparently been worked on, and all components may not be present. However, the gyro does spin when manually rotated. Note the appearance of some corrosion internally. Would make a very cool display. See photos. PDF copies of the A-12 manuals can be provided if desired.