TBF-1 Avenger Torpedo Bomber Cruising Calculator Mark 1-A, Ser # 0300-43

This 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 consisting of 4 components: The first component is a metal base providing attainable ranges under various aircraft weight and fuel on board, and has curled edges at top and bottom with a retention spring to grip the 3 sliding panels.  The next two components are two hard-plastic sliding 'weight' panels each displaying 5 performance curves along air speed x-axis and fuel consumption rate (gallons per hour) y-axis for a specific aircraft weight. The 5 performance curves are for altitudes of sea level, 6000ft, 9000ft, 13000ft, and 20000ft. Each pa