NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Wrapped Bygrave
From: Wolfgang Hasper
Date: 2010 Jan 17, 17:41 +0100
From: Wolfgang Hasper
Date: 2010 Jan 17, 17:41 +0100
Making a "real" cylindrical slide rule is quite complicated, main obstacles are - tubes needed to specific uncommon diameters - need for precision in diameters - precisely fit the scales to the circumference of tubes - locking mechanisms required ;o) and surely more. The flat bygrave is a great step towards a cheap and simple implementation of the principle. While it is ideal for storage it can be hard to use when no desk is available or wind is present. As an experiment I printed both flat scales on film, punched them on both short sides and wrapped them around a pipe, using elastic ribbons to have some tension on the film. (see photos) Works good and has enough friction to keep any setting. No need for any particular tube diameter. No need to precisely align scale ends either. If needed even a cursor can be drawn on the tube. The two film scales slide together if you want. For this first model I had to use 100mm sewage pipe as core because the scales were made "landscape" not "portrait". Using rearranged scales for "portrait" A4 will allow for a handier 70mm pipe. Within the pipe there is again enough space for emergency documents, pens, paper... While I do have the fortran programme I cannot handle it. If any of the scale producers were interested in making a rearranged version I would be happy to make more experiments. What do you think? Can the advantages of the tubular setup (handling) and of the flat printout (ease of production) be combined this way? Wolfgang