Suction Gage, AN 5771-5, US Army Air Force WWII C-47 the difference between the totals

the difference between the totals is the difference in density of the two fuel types

It is a hand held finder used to ascertain the range of an enemy aircraft based upon its known wingspan

Both are labeled "AF US ARMY" on their faces

was the premier heading reference system for high-latitude flying in North America throughout the early nineteen fifties

Suction Gage, AN 5771-5, US Army Air Force WWII C-47 the difference between the totalsThis is a WWII era Suction Gage, AN 5771 5, made by Collens. This indicator has a serial number prefix "AF 43", evidence of a manufacturing year 1943. The AN 5771 5 Suction Gage was used across all aircraft of the US Army Air Corps, including bombers B 17, B 24, B 25, fighters P 38, P 40, P 47, P 51, and transport C 47. The Suction Gage measured the amount of vacuum generated to power the pneumatically operated gyroscopic instruments, such as the Gyro