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Speed drift & direction calculator - airship
Speed, drift & direction calculator, used on RN airships during the First World War. It is also known as a course and distance calculator.
Three plates revolve around a central nut. The largest plate has scales for time or distance, the middle plate for points of the compass and minutes, and the smallest plate is a grid with four sets of graduations at 90 degree intervals, of 30-110, radiating from the centre. There are also two arms graduated 20-110 radiating from the centre.
Rear surface: plain, painted cream/white.
Appears to be the earliest pattern of this form of calculator as it does not carry the later Mk I or Mk II designations. Its purpose is to solve the vector navigation triangle of speed, direction, distance.
Diameters of plates: large 7" (17.8 cm), Medium 6.5" (16.5 cm), Small 4.75" (12.1 cm)
Length of arms: 2.5" 96.4 cm)
Three plates revolve around a central nut. The largest plate has scales for time or distance, the middle plate for points of the compass and minutes, and the smallest plate is a grid with four sets of graduations at 90 degree intervals, of 30-110, radiating from the centre. There are also two arms graduated 20-110 radiating from the centre.
Rear surface: plain, painted cream/white.
Appears to be the earliest pattern of this form of calculator as it does not carry the later Mk I or Mk II designations. Its purpose is to solve the vector navigation triangle of speed, direction, distance.
Diameters of plates: large 7" (17.8 cm), Medium 6.5" (16.5 cm), Small 4.75" (12.1 cm)
Length of arms: 2.5" 96.4 cm)
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Object Details
| ID: | NAV0137 |
|---|---|
| Type: | Speed drift & direction calculator - airship |
| Display location: | Display - Forgotten Fighters |
| Creator: | Unknown |
| Events: | World War I, 1914-1918 |
| Date made: | circa 1915 |
| People: | York-Moore, Thomas Philip |
| Credit: | National Maritime Museum, Greenwich, London |
| Measurements: | Overall: 10 mm; Diameter: 180 mm |