Free Air Temperature Indicator, Type C-8 US Army Air Corps Weston 728 T-20
This is an exceptional example of the WWII-era electrical Free (i.e., ambient) Air Temperature Indicator, US Army Air Corps Type C-8, as used in versions of the heavy bomber B-24 (see photo of instrument panel from a B-24 Flight Manual showing the location of the indicator), also medium bombers B-25 C/D Mitchell and B-26 B/C Marauder, transports C-87 and C-45, and trainers AT-7 and AT-11, according to the Maintenance Interchangeability Cross Reference Chart dated Dec 1943. It indicated outside air temperature from -45deg to +45deg C. The C-8 was illuminated with a small 3V lamp knob in the upper right corner. AC US ARMY is embossed on its face, evidence of a manufacturing year on or before 1943. This C-8 was made by Weston, model 728 T-20.
Measures 3.25 inches diameter and ~3.5 inches deep. It is in exceptional condition given its age. The glass is clear and the case is intact. The dial lettering is distinct.