Control Unit C-4, of ARN-7 Automatic Radio Compass, B-17, B-24, B-29 Mosquito This indicator provided a feedback

This indicator provided a feedback loop to the crewman thus enabling him to ensure proper wing temperature

The type of aircraft which used this tachometer has not yet been identified by us

black dial stopwatch under military specification no

When it is being used

Control Unit C-4, of ARN-7 Automatic Radio Compass, B-17, B-24, B-29 Mosquito This indicator provided a feedbackHere is a WWII era Control Unit for the ARN 7 Automatic Radio Compass system used for direction finding and homing. The receiver function tunes from 100 1750 kHz across 4 bands, which were selected by rotating the center knob below the frequency band window. The center knob rotates a flexible shaft connected to a rotatable loop antenna. The ARN 7 system (see diagram), were one of several generations of radio navigational systems installed in an