TBF-1 Avenger Torpedo Bomber Cruising Calculator Mark 1-A, Ser # 5031-43 B-47 used to calibrate the compass

used to calibrate the compass

shifts the index line in the small round window at ~19

who was a maker/distributor of drafting and surveying instruments and supplies

The dial markings are clear and the glass and cases are intact

The data plate is absent from this example

TBF-1 Avenger Torpedo Bomber Cruising Calculator Mark 1-A, Ser # 5031-43 B-47 used to calibrate the compassThis is an authentic original WWII era Cruising Computer Mark 1 A designed specifically for the US Navy's Grumman Torpedo Bomber TBF 1. The purpose of the calculator was to determine the range, in nautical miles, of the aircraft under various conditions of aircraft weight, head tail winds, fuel quantity on board, true air speed, altitude, and throttle and supercharger blower settings. The calculator is essentially a custom 3 panel slide rule