Aristo Radar-Wind-6307-Rechenscheibe
This 13.5in diameter Desktop High Altitude Calculator, was fabricated in Hamburg, Germany by Aristo - Dennert & Pape, in the 1960's. No precise year can be stated because there are no engraved characters indicating a date, as usual in the Aristo slide rules. Fabricated with Astralon, this thick circular High Altitude Calculator was for military use, and is in essence modern adaptations of a traditional Artillery Range Finder slide rule or graphic plotter, according with David G. Rance, and could have been used to plot incoming or outgoing missile trajectories. However, they could have been used as a latter-day “Pilot Balloon” slide rule to track the likes of the jet stream and its effect on missiles or planes flying at high altitude.
The 6307 has three scales: the outer, printed on the from movable disc, is a regular logarithmic C-scale labeled from 100 to 999, The two concentric inner are a standard trigonometric sine-cosine S-scale split in two parts, the internal running from 0.573 to 5.73 degrees , and the external running from 5.73 to 90 degrees. It has two fully movable identical cursors with two hairlines each, red color the left one, and black the right one. The back face is blank. It comes in a sturdy olive green (discolored with the years) fabric bag.
Aligning the two black triangles on the scales, the values of Sine and Cosine functions can be read on the outer scale. The solution of the Law-of-Sines is relatively simple with this rule. But there are a couple of questions I have not been able to answer yet: Why two cursors? Why two lines on each cursor? I have not found the User Manual for this rule or any book making reference to it yet, so this questions are still baffling me.
Click on the next links to see panoramic pictures of other Radar-Wind models in Mr. David G Rance 's collection :
Aristo 60126- Angle Scales in mils:
Nestler 939 Rechner, Hoehenwindmessung
References:
Rance, David G.: Squaring the Circle - Overlooked Nestler Models: https://sliderules.nl/media/papers/Gazette_19_Squaring_the_Circle.pdf