Flap Position Indicator B-24 Liberator, PB4Y Privateer, WWII GE DJ11 Oscar Fighter Above the center axis is

Above the center axis is a window to display barometric pressure in millibar

This indicator has a serial number prefix "AF-43"

An early model was delivered to Dayton late in 1945 and then subjected to an extensive flight test program primarily at Boca Raton

This 48-page booklet

The knob at the bottom is used to adjust variation

Flap Position Indicator B-24 Liberator, PB4Y Privateer, WWII GE DJ11 Oscar Fighter Above the center axis isThis is a Flap Position Indicator as used in the WWII era Consolidated US Army Air Force B 24 Liberator Heavy Bomber (see 2 cockpit photos and photo from the B 24 Pilots Manual dated 1944) and the US Navy's PB4Y4 Privateer Patrol Bomber (see photo from Flight Manual dated 1945). Made by General Electric, Type DJ11. The indicator provided visual information on the angle of extension of the wing flaps during take off and landing, measured from full up