INTRODUCTION

Its usage is identical to that of a real slide rule, but we introduce two major enhancements: you can select from a large scale and feature list to build your own slide rule collection, and the slide rules you build can be stretched very, very long for high precision.

This website is the companion manual, and it covers installation, usage, and a good deal of detailed explanation and examples concerning the scientific scales found on real and virtual slide rules alike.

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WHY?

Slide rules teach you math

Calculators give the answer without requiring any knowlege of the function requested. All you learn is that "cos(95) is the number you get from pressing 9,5,cos". Slide rules are inconvenient because you need to understand more than that to get the right answer. You won't even find a 95 on the cos scale. You won't even find a scale called cos! This inconvenience is a really good thing. You make less mistakes when you know what's going on. You're forced to know the meaning of functions and their ranges, and what a reasonable result would look like. You have to know identities, float your own decimal points, and do quick adding in your head.

Big scientific slide rules are collector's items

This is only going to get more true as time passes. Only a handful of the thousands of models once produced are still made. The best ones in the best condition are auctioned for high prices. If you have an interest in slide rules, the Griffenfly Rule allows you to build a virtual collection, and to experiment with your own ideas about scale arrangements without purchasing multiple rules. It allows anyone and everyone to have a high end scientific slide rule, no matter how rare the others become. If you don't care to build your own slide rule, the installation provides five default slide rules: Mannheim, Rietz and Darmstadt standard arrangements, plus two large scientific duplex rules: the Griffenfly T1 and V1.

The Griffenfly Rule is incredibly precise for a slide rule

It delivers at least 5 decimal places at max zoom, often 6. You could use it instead of a calculator for most math, science, and engineering problems. That said, it's still solely a slide rule, not a calculator. You can't "cheat" ( by setting scales to exact numbers for instance ) - the precision derives from the huge zoom factor. But even without the zoom, if you have a decent screen resolution, you can get the same or better precision than a 10 inch rule. There are other features besides zoom which contribute to its precision.

It's kind of fun

Slide rules provide a different, more visual way of performing quick calculations, and this one provides an intuitive mouse driven interface designed for speed. It's a challenging mental sport, and there's a satisfaction derived from mastering the black art of choosing the correct scales and the minimum movements to produce the fastest, most precise results. There still exists a large community who find something elegant in the simplicity of the slide rule. Hopefully that community might become larger.