Compass, Aperiodic, US Military Aircraft, Pioneer 1811-1-D C-45 indicates the manufacturing year 1944

indicates the manufacturing year 1944

The design of the mounts of aircraft instruments evolved during early WWII from the dog-ear-style as seen on this instrument to a more robust integral design that was less vulnerable to breaking on a hard landing

Measures approximately 4 inches square and 2 inches deep

but seems to run

but could probably be recalibrated with the compensator screws

Compass, Aperiodic, US Military Aircraft, Pioneer 1811-1-D C-45 indicates the manufacturing year 1944This appears to be a post WWII Direct Reading Aperiodic Compass used at the navigators station in US military aircraft. Made by Bendix, part number 1811 1 D. It appears to have never been put into service judging from its superb condition. An aperiodic compass, after being deflected, returns by one direct movement to its proper reading, without oscillation. It is similar to a WWII era D 12 compass, which was typically mounted on the navigator's desk.