NavList:

Frank
I could tell you but, . ..... ... .. .... ... . 
What we did have in the Dominie Navigation Trainer in the 70s was Decca Mk 1 Air.  At the speed we flew, the poor old Nav spent most of his time chain changing, maybe managing to mark one, or two if you were lucky, fixes on a paper Decca chart between chain changes.  To keep the pilots quiet, they had an amazing device which used the values of two of the three Decca lines (were they red, green, and purple?), and fed them to a X-Y plotter in front of the pilots.  To make that work, they took appropriate scrolls out to the aircraft with them.  Yes, they really were rolled up scrolls wound up on a spindle which could be popped into the machine.  The outline on those looked like nothing you'd seen in your life before, and they appeared to have none of the properties of the 'ideal chart'.  Instead of using hyperbolic Decca lines,  The made the Decca lines straight and distorted the Earth instead. DaveP