TBF-1 Avenger Torpedo Bomber Cruising Calculator Mark 1-A, Ser # 4669-43 Smiths as used on US Navy

as used on US Navy aircraft with wing-mounted bomb racks such as the TBD Douglas Devastator Torpedo Bomber

The left knob adjusts the indicated airspeed which is displayed in the left window

November 1943

its purpose is unknown to us

at 9 x 7 x 4 inches the unit is larger than one might regard a handset

TBF-1 Avenger Torpedo Bomber Cruising Calculator Mark 1-A, Ser # 4669-43 Smiths as used on US NavyThis 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