Dalton E-6B Dead Reckoning Computer by Jeppesen
date: label: date made
content: 1960s
name: label: maker
content: Jeppesen & Co.
notes: label: Description
content: In this instrument a white rectangular plastic sheet slides between two white discs that are held together with black plastic bars and metal grommets. The sheet is marked in green on both sides, with a polar grid and rectangular grid on one side and a polar grid on the other side. The front disc has scales for altitude computations at the top and for air speed computations at the bottom. The back disc has a scale to correct direction readings for wind and a scale for converting temperature readings from degrees Centigrade to Fahrenheit. The center of the back disc is clear for viewing the grid. A salmon plastic sheath stores the instrument.
label: Description
content: The device is marked on the front: DALTON DEAD RECKONING COMPUTER (/) TYPE E-6B. It also is marked: WEEMS SYSTEM OF NAVIGATION (/) (A DIVISION OF JEPPESEN & CO.) (/) DENVER, COLORADO; PAT. NO. 2,097,118. The grid is marked in pencil: FL[IGH]T OFF COURSE (/) 2 MILES/SQUARE. The back of the disc is also marked in pencil. The three lines in the clear part of the disc are illegible, but below the temperature conversion scale, the marks read: 3.5° F/1000'. A ring at the top of one black plastic bar is marked: U.S. PAT. 3,112,875.
label: Description
content: Naval Reserve pilot Philip Dalton, in consultation with navigation instructor Philip Van Horn Weems, developed the Dalton dead reckoning computer for the U.S. Army Air Corps and received a patent in 1937. The device was widely used during World War II.
label: Description
content: After the war, many manufacturers in the United States and Europe made the E-6B. Elrey Borge Jeppesen, a pilot for what became United Airlines, founded his company in 1934 and moved it to Denver in 1941. Jeppesen & Co. made aeronautical charts and navigational tools and guides. It became a subsidiary of Boeing in 2000. The patent number on the back of this object refers to the design of the computer with the gridded rectangular sheet and two discs. The patentees were employed by Felsenthal Instruments Co., which frequently supplied companies with the plastic for manufacturing Dalton computers in the 1950s and 1960s.
label: Description
content: The donor purchased this object around 1965 and used it for about two years in airplane navigation.
label: Description
content: References:
label: Description
content: Paul McConnell, "Some Early Computers for Aviators," <i>Annals of the History of Computing</i> 13, no. 2 (1991): 155–177, on 156. Philip Dalton, "Plotting and Computing Device" (U.S. Patent 2,097,116 issued October 26, 1937).
label: Description
content: Ben Van Caro and Burton L. Fredriksen, "Computer Slide Construction" (U.S. Patent 3,112,875 issued December 3, 1963). "E6B," http://en.wikipedia.org/wiki/E6B.
label: Description
content: "Jeppesen," http://en.wikipedia.org/wiki/Jeppesen.
label: Description
content: "On the Beam," advertisement for Dalton Dead Reckoning Computer, Felsenthal Plastics, <i>Flying</i> 35, no. 2 (August 1944): 10.
label: Description
content: Paul Sanik, "U.S. Army Air Corps Aerial Dead Reckoning type E-6B," <i>Journal of the Oughtred Society</i> 6, no. 2 (1997): 32–34 .
label: Location
content: Currently not on view
place: label: place made
content: United States: Colorado, Denver
topic: label: Subject
content: Mathematics
label: Subject
content: Navigation
setName: label: See more items in
content: Medicine and Science: Mathematics
label: See more items in
content: Plotting Boards
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content: Science & Mathematics
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content: Slide Rules
creditLine: label: Credit Line
content: Gift of William E. Gilbert
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: 1995.0087.03
label: accession number
content: 1995.0087
label: catalog number
content: 1995.0087.03
objectType: label: Object Name
content: plotting board
physicalDescription: label: Physical Description
content: metal (part material)
label: Physical Description
content: plastic (overall material)
label: Measurements
content: overall: 1 cm x 12.5 cm x 24.3 cm; 13/32 in x 4 29/32 in x 9 9/16 in