Autopilot Slaved Gyro Magnetic Compass, USAF E-4 System, 667258-21 P-39 as used in the US

as used in the US Navy's Patrol Bomber and Sub Chaser the Lockheed P-2 Neptune (see photo of page from the P2V7 Neptune flight manual dated 1961 depicting the instrument location on the cockpit panel with a red dot)

M6 periscopes in each late model Sherman

24 inches diameter and ~2

but is very similar to the earlier model designated BC-929-A used in the AN/APN-2 system

This is a dual engine Intercooler Flap Position Indicator as appeared on the US Air Force's Korean War-era Boeing B-50 Superfortress

Autopilot Slaved Gyro Magnetic Compass, USAF E-4 System, 667258-21 P-39 as used in the USThis is an example of an Autopilot Slaved Gyro Magnetic Compass, Type V 3, for the USAF Autopilot Type E 4 (aka as the Sperry A 12 Gyrosyn Automatic Pilot System). The E 4 System was used in the late 1940 1950's and was still in use in some 1960's aircraft. Lockheed C 130 Hercules and C 121 Constellation transports used this system, as well as civilian aircraft such as DC 3 and DC 6. The Indicator is in reasonable condition for its age. The glass is