Intercooler Flap Position Indicator, Boeing B-50 Superfortress Bomber, Type DJ-28 F-14 The LS-3 Loudspeaker was used

The LS-3 Loudspeaker was used during WWII with a variety of US Army Signal Corps receivers

fighters P-38

See photo of the Co-Pilots Panel of a B-50D from its flight manual

the navigator observes the travel of fixed objects across the lens

It is mostly filled with fluid and the compass card rotates

Intercooler Flap Position Indicator, Boeing B-50 Superfortress Bomber, Type DJ-28 F-14 The LS-3 Loudspeaker was usedThis is a dual engine Intercooler Flap Position Indicator as appeared on the US Air Force's Korean War era Boeing B 50 Superfortress, a more powerful engine revision of the iconic WWII B 29 bomber Measures. Two of these indicators appeared on the B 50's engineer's instrument panel (see photo), each indicating the intercooler flap position on engines 1 & 2 or 3 & 4. By toggling the momentary contact intercooler switches, the flight engineer controlled