MIL-DTL-48559 Mount, Telescope And Quadrant - M172A1This specification covers the Mount, Telescope and Quadrant: M172A1 which supports the Fire Control Quadrant: M18A1 for use on the M777 and M198 series of howitzers and gives elevation compensation to correct for cant when the mount is leveled by a cross level movement. The mount also supports and aligns the mounting bracket for the Elbow Telescope: M138A1.

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MIL-DTL-48559B

2.3 Order of precedence. Unless otherwise noted herein or in the contract, in the

event of a conflict between the text of this document and the references cited herein, the

text of this document shall take precedence. Nothing in this document, however,

supersedes applicable laws and regulations unless a specific exemption has been obtained.

3. REQUIREMENTS

3.1 First article. When specified (see 6.2), a sample shall be subjected to first

article inspection in accordance with 4.2.

3.2 Conformance. A sample shall be subject to conformance inspection in

accordance with 4.3.

3.3 Mount. The mount shall conform to drawing 13005089.

3.4 Environmental.

3.4.1 Storage temperature. While thermally stabilized at temperatures of +160 �

5�F and -60 � 5�F, the mount shall be inspected and shall not exhibit any signs of physical

failure or damage. Upon return to and stabilization at standard ambient temperature, +60�F

to +90�F, the mount shall meet the requirements of 3.5 through 3.10 inclusive.

3.4.2 Operating temperature. The mount shall meet the requirements of 3.5, 3.7,

3.8, and 3.9 inclusive while exposed to and thermally stabilized at temperatures of +145 �

5�F and -50 � 5�F. Upon return to and stabilization at standard ambient temperature,

+60�F to +90�F, the mount shall meet the requirements of 3.5 through 3.10 inclusive.

3.4.3 Shock. The mount shall withstand a total of 75 shock impulses, 15 in each

direction of 3 mutually perpendicular axes as defined in Figure 1. Each shock impulse

shall be a half sine wave with a time duration of 0.010 � 0.001 seconds and peak amplitude

for each shock impulse as shown in Table I. Subsequent to shock, the mount shall show no

evidence of damage or physical failure and shall meet the requirements of 3.5 through 3.10

inclusive.

TABLE I. Shock orientation and impulse.

Orientation

Shock impulse and direction

Number of impulses

Longitudinal

-50 g's, +40 g's

15 each direction

Vertical

-30 g's, +30 g's

15 each direction

Transverse

-20 g's

15 total