Plotting Board Mark 3A by G. Felsenthal and Sons

Plotting boards of this sort were standard equipment for pilots flying from U.S. Navy aircraft carriers during World War II. The large rectangular sheet of clear plastic has a white disc pivoted to it on which a grid of green lines is indicated. It has scales allowing for course corrections due to magnetic variation and wind speed. The back of the disc is also printed, but the range of speeds goes from 0 to 230 rather than 0 to 170. A mark on the corner of the rectangular sheet reads: AIRCRAFT NAVIGATIONAL (/) PLOTTING BOARD (/) MARK 3A F.S.S.C. No. 88-B-770 (/) BU, AERO. U. S. NAVY CONTRACT NO. N28s-4359 (/) G. FELSENTHAL & SONS, CHICAGO, ILL.
A small white plastic square with a round disc atop it is riveted to the right corner of the rectangle. It allows for corrections to air speed in relation to air temperature and altitude. It is marked: BU. AERO. U. S. NAVY (/) AIRCRAFT NAVIGATIONAL (/) COMPUTER (/) MARK 8 (/) F.S.S.C. NO. 85-C-1150.
The instrument is stored in a cloth case with a snap.
Both the inside of the flap of the case and the larger board are marked with the initials HEA. The object came to the museum from the mathematics department of Wesleyan University. One member of that department was the statistician Herbert E. Arnold (1896-1957). According to the Wesleyan University Archives, Professor Arnold, along with other faculty, taught for Wesleyan's Navy program during World War II. One part of this program, the V-5 Naval Training Unit, was also called the Navy Flight Preparatory School, and stayed at Wesleyan from January 1943 until August 1944. Coursework focused on aerology and naval science. Whether Arnold taught in this particular program is not clear. He did teach in a V-12 program, which included classes more like Wesleyan's usual liberal arts curriculum.
A similar plotting board is in the collections of the National Air and Space Museum.
Personal Communication, Special Collections and Archives, Olin Library, Wesleyan University, June, 2016.
Herge, Henry C. Navy V-12, Paducah, KY: Turner Publishing Company, 1996. The volume has a photograph of Arnold teaching in a V-12 program at Wesleyan.
Currently not on view
Object Name
plotting board in case
date made
ca 1945?
ca 1944
Felsenthal Instrument Co.
Physical Description
metal (overall material)
cloth (overall material)
plastic (overall material)
overall: .2 cm x 35.5 cm x 42 cm; 3/32 in x 13 31/32 in x 16 17/32 in
place made
United States: Illinois, Chicago
ID Number
catalog number
accession number
Science & Mathematics
Plotting Boards
See more items in
Medicine and Science: Mathematics
Plotting Boards
Data Source
National Museum of American History, Kenneth E. Behring Center
Credit Line
Gift of Wesleyan University
Additional Media

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