Plotting Board Trainer M16, Felsenthal Instruments Company Model FNR-38

Plotting Board Trainer M16, Felsenthal Instruments Company Model FNR-38

Usage conditions apply
At least as late as 2004, weapons sergeants in the United States Army (people with the job title computer) were trained to use plotting boards like this one, in combination with other materials, to plot the location of mortars, targets, and reference points, and to determine the direction of fire, mounting azimuth, and deflection of azimuth for weapons.
This version of the M16 plotting board has a transparent plastic base that is square on one side and semicircular on the other. A circle marked with a grid of lines is printed on the base, and a vernier for finding azimuth deflections is along the top edge. A rotating disc pivots at the center. Distances are measured radially from 0 at the center to 3400 meters. Angles around the rim range from 0 to 6400. Scales for reading maps, given in metric units, are along the right edge. A scale pivoted at the center atop the disc assists in reading distances.
A mark in the upper right corner reads: PLOTTING BOARD-M16 (/) DEVICE 17E5 (/) MODIFIED FOR INSTRUCTIONAL (/) PURPOSES ONLY. It also reads: A PRODUCT OF (/) NDC (/) U.S. NAVAL TRAINING DEVICE CENTER. Text in the bottom right reads NAVAL TRAINING DEVICE CENTER (/) ORLANDO, FLORIDA 32813 (/) MFR. BY (/) FELSENTHAL INSTRUMENTS CO. (/) 22040 (/) CONTRACT NO. N61339-70-0185.
Objects 1977.114.04 and 1977.1141.31 are very similar – the first has a white plastic base, the second a transparent plastic base.
The accession file indicates that this object dates from 1970.
U.S. Department of the Army, Soldier’s Manual and Trainer’s Guide MOS-18B Special Forces Weapons Sergeant Skill Levels 3 and 4, 2004, esp. pp. 3-122-3-130. Use of then-current version of the M16 plotting board described.
Accession file.
Currently not on view
Object Name
plotting board
date made
ca 1970
Felsenthal Instruments Co.
Physical Description
plastic (base; disc; rule material)
metal (pivot material)
overall:.2 cm x 31 cm x 30.5 cm; 3/32 in x 12 7/32 in x 12 in
ID Number
catalog number
accession number
Credit Line
Gift of Ben Wharton Rau and Margery Felsenthal Rau
See more items in
Medicine and Science: Mathematics
Plotting Boards
Science & Mathematics
Data Source
National Museum of American History
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