Product Overview: Quadrant, Fire Control: Elevation, M13
NSN: 1290-00-765-2218
P/N: 7652218

General Description
Quadrant, Fire Control: Elevation, M13 is a unit of the indirect fire control system of a tank. It is used with the ballistic drive to set the desired elevation on the gun. It consists of an elevation knob and worm, elevation micrometer, level vial, reflector, and elevation scale. The elevation scale is graduated in 100-mil intervals from minus 200 to plus 600 mils. An elevation knob, with an attached micrometer, is provided to "set in" elevation or depression angles. The micrometer scale is graduated in 1-mil intervals from 0 to 100 mils on two scales, reading in opposite directions, elevation angles being read on the inner scale and depression angles on the outer scale. Turning the elevation knob in setting an elevation or depression angle, will rotate the housing on which the scale index and level vial are mounted, and will displace the bubble from center. When the weapon is elevated or depressed sufficiently to return the bubble to center, it is aimed to the elevation or depression set on the scale, movement of the weapon being transmitted through linkage to the ballistics drive or the gun recoil guard on which the quadrant is mounted. A reflector, set at a 45-degree angle over the level vial tube allows for easy viewing of the level vial, which is above eye level of tank personnel.

The M13 quadrant is used with Drive, Ballistic: M3 on Tank, Combat, Full Tracked: 90mm gun, M47 and Drive, Ballistic: M6, on Tank, Full Tracked: 105mm, M103.