TBF-1 Avenger Torpedo Bomber Cruising Calculator Mark 1-A, Ser # 4669-43 Smiths The left knob adjusts the

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

the fine engraving on the silver scale and arm

Adapter rings were also available for fitment of either A-1 or A-2 tilting heads for use as a fixed gunnery gunsight on attack and light bomber plane(c)

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

flight instruments

TBF-1 Avenger Torpedo Bomber Cruising Calculator Mark 1-A, Ser # 4669-43 Smiths The left knob adjusts theThis 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