Tank Range Card

This chart, drawn on a rigid white plastic sheet, has five equally spaced concentric circles, each divided into eight equal sections by lines through the center of the circle. The outer circle is divided into 64 equal segments, which are numbered counterclockwise from 0 to 32 on the left half of the circle. On the right half, segments are numbered from 0 at the bottom counterclockwise to 30 at the top, and also from (34) to (64).

A mark at the bottom left reads: CARD, TANK RANGE (/) 8724207. A mark on the left top reads: HUNDREDS OF MILS. There are 6400 mils in a circle of 360 degrees angular measure.

The object comes from the Felsenthal Collection of computing devices. According to the accession file it was made by Felsenthal for the U.S. Army in 1955, and had Felsenthal designation FA0-51. It may have been used by the tank gunner to lay his gun on target, before the availability of electronic or laser sighting.

Reference:

Accession file 1977.1141.

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