Objects

The navigation calculator with a case

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A mechanical navigation calculator with a leather case - Henryk Rozental's keepsake from his service in the Polish Air Force (PSP). The instrument is made of two fragments of metal sheet on which the graduations for making calculations have been embossed. The outer fragment of metal is movable and circular. It is fixed to a metal sheet which corresponds to the circle on top, but which turns into a rectangle in the middle of its height, by means of a rivet. Along the straight (bottom) edge a scale with kilometres (scale 1:1,000,000) has been embossed. Along the edge of the circle (on the outer side), a graduation line showing the kilometres is also visible. Along the inner edge of the circle the graduation scale indicating the time (in min.) is visible. Additionally, inside the circle a table signed "Speedometer indications km/hr". Below the table there is information about the manufacturer: "Wytwórnia Instrumentów Lotniczych Warszawa", and below it the factory number of the device: "1219". On the reverse of the plate (at the bottom, along the straight edge) the kilometre scale was also placed, but this time on a different scale (1:300,000). Above it, there is a table indicating the dependence of plane speed on wind direction and speed. The calculator is equipped with a pouch in a shape corresponding to the shape of the instrument. The case is fastened with a clasp. The instrument was used to calculate the distance an aeroplane covered in a given time at a given speed. The outer scale was used to indicate the speed of flight, the inner scale to indicate the time of flight. A table in the middle was used to calculate the actual distance travelled in relation to the ground surface. Such instruments were necessary to calculate fuel consumption and fuel requirements along the route. The table in the back helped to calculate the angle of drift depending on wind speed and direction and the speed of the aircraft.

Marta Frączkiewicz

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Information about the object
Organization / label
Wytwórnia Przyrządów Lotniczych Warszawa (Warszawa; 19..-19..)
Time of creation / dating
20th century
Place of creation
Warszawa (mazovian province)
Technique
cutting
bending
pouring
printing
joining
Material
alloy
paint
Keywords
Copyrights status
the object is not protected by copyright law
Owner
POLIN Museum of the History of Polish Jews
Identification number
MPOLIN-M1101/1
Localization
The object is not currently on display
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