Slide rule for trigonometric calculations esp for flight navigation - has base and cover parts with diagram panels

摘要

The diagram panel (3) of the base part (1) is on a carrier (1a) and consists of arcs (4) with equal radii which are displaced at equal intervals along a diameter line and of diagram line and of diagram lines (6) running parallel to the diameter line. These diagram lines form, with the arcs, intersections resulting from angle plotting on the diameter line at the centre of the associated arc. The disc-shaped cover part has an angular division of 360 deg. and has circles concentric to the centre of the angular divison. The preferred circles for plotting are those running through the intersections of the standardised arcs with the diameter line.