Altimeter, Tyco, 20,000FT, WWI to 1920's US Navy Japanese The dial markings and paint

The dial markings and paint on the pointers have aged

AN/ARN-30 was used in versions of the following aircraft: UH-1

and cost $2

The box is 10 inches wide

as well as a hand-written electrical diagram

Altimeter, Tyco, 20,000FT, WWI to 1920's US Navy Japanese The dial markings and paintHere is an Altimeter used in early military aircraft of the US Navy, very similar to the Type C altimeter used by the Army Air Service from WWI thru 1926. Crudely measured altitude from 0 20,000 ft, which was pretty high for aircraft of that era and requiring supplemental oxygen for the crew to exceed ~12,500 ft based upon modern standards. The knob rotates the face of the dial while the pointer remains fixed to set the present field elevation.