Air Position Indicator System Computer 12580-1-B DC-7 and the bubble is full

and the bubble is full and intact within the glass chamber

evidence of manufacturing year of 1948 for a USAF order

and the fill port on the bottom has a small crack

the pitot tube was employed by pitot-statically-driven instruments to perform their function

Air Position Indicator System Computer 12580-1-B DC-7 and the bubble is fullThe Air Position Indicator System was an advanced navigational system introduced during WWII in later versions of the Boeing B 29 Superfortress Bomber by the US Army Air Force, including the Enola Gay (see API on navigator's panel). This electro mechanical system computed positions based on a series of dead reckoning inputs. The system maintained a continuous indication of the latitude and the longitude of the air position at any instant, as well as