Hyperbolic Match Output
Model:989 Complex Hyperbolic Function Calculator
Source: Hopp page 172. and D.v.J. and Peter Holland and R.H.
Information: This very unique "Calculator" is shown in the 1966 F-C catalog. It is very large; about 21 x 31 cm., and its picture shows a rule full of graphs of families of curves. Although it has two movable cursors to read values off of the graphs it works more like a nomograph than a slide rule. Peter sent me translations that Dieter made of the Manual. Using this device you can find solutions to equations involving complex hyperbolic functions. Richard Hughes, kindly sent me very clear and complete full size pictures of his F-C 989. (See his excellent JOS article, Vol. 16, No. 1, and JOS Plus, May 10, 2008). Of interest is that all calculations are based upon the 400g system.