Pelorus, Aircraft, US Navy Mk I 18-P-21690 AT-6 the upper center indicator displays

the upper center indicator displays a flap symbol along the scale showing the amount of flap deployed

All of the knobs turn and toggles flip

To pause the top timer rotate the center knob until the bottom flag is white

Measures 3

The knobs turn freely

Pelorus, Aircraft, US Navy Mk I 18-P-21690 AT-6 the upper center indicator displaysThis is a WWII era Aircraft Pelorus Mk I used by air navigators in the US Navy. The Pelorus was used for taking bearings on objects of interest, be they celestial or terrain. The bearing sight (the cross bar) can be inclined or declined on its center axis, and rotated to the desired bearing which can be read on the base scale. Drift angle can also be determined. Measures approximately 5 inches diameter and 4 inches tall.