Radio Compass Heading Indicator, Type IN-4D, for Bendix System
Here is an authentic vintage aircraft Radio Compass Heading Indicator made for the Bendix Radio Compass system by The WW Boes Co., Type IN-4D. It is very similar to I-65 compass indicators used in aircraft of the Air Corps US Army during WW2 (the primary difference in appearance being the centerpoint of direction, which is designated by a vertical dash on this one and by a small aircraft silhouette on the I-65). The indicator receives an electrical signal from the internal radio compass system, which is receiving a signal from a ground station (e.g. an airport or stations along a specific route) via externally-mounted antenna. If the station is to the left or right of the aircraft, the needle points left/right, prompting a left/right turn towards the station, thus allowing the needle to return to center. A simple but very useful instrument at the time.
The instrument is exceptional condition for its age. The glass has a small crack at ~7pm on its face. The dial markings are clear and the case is intact. Has a service label of Sept 15, 1950.