History of the Distance Computer

The distance computer that we have been using is simple type of circular slide rule. This is the kind of device that people like engineers and pilots regularly used before pocket electronic calculators were developed.

The E6-B Flight Computer

The picture below shows an example of a flight computer.  Similar devices were produced in great numbers for the U.S. Army Air Corps in World War II, and they were given the Army designation E6-B.  They have continued to be used by pilots since then.  Airliners and corporate aircraft now have digital instruments that perform the same functions, but most pilots still have an E6-B somewhere in the bottom of their flight bag for use in case the digital instruments fail.

An E6-B flight computer

The Engineering Slide Rule

Slide rules were also made in a linear, rather than circular design.  The picture below shows part of a classic K&E engineering slide rule made in the late 1960s.

A K&E engineering slide rule

This is the end of the trail.  Back to base camp.

(Unless you want to know how the distance computer really works. But you can't get to that secret until you have studied Algebra.)  Yes I have studied Algebra and I want to know the secret.