ASA Electronics E6-B manual The Slide Rule Side

The Slide Rule Side

The term “circular slide rule” shouldn’t be intimidat- ing. This side of your computer simply consists of a rotating disk with numbers on the middle scale, which when set against similar numbers on the fixed portion (outer scale), allows you to solve problems of time, speed, and distance, calculate fuel consumption, and make conversions be- tween measurements such as statute and nauti- cal miles. The inner scale on the rotating disk is graduated in hours. The slide rule side also has “windows” that you will use to solve airspeed and altitude problems.

You can see that the number 60 on the rotating disk is marked differently than the other numbers. That is because most of your problems will be concerned with time —“something” per hour, either miles or gallons. Before you get to that, you should learn how to read and interpret the numbers on both portions of the slide rule side.

Rotate the disk until all of the numbers on the middle scale match up with the numbers on the outer scale —10 will be at the top. However, that number “10” may be read as “.1,” “1,” “100,” or “1,000” depending upon the context of the problem. For now, read it as 10. The next number to the right is 11, so each life (or mark) of calibration between the two numbers is equal to .1, and you would read them as 10.1, 10.2, 10.3, etc. If you were solving a problem involving 1,000 pounds of fuel, the number 10 would be read as 1,000, and each calibration would be equal to 10 pounds, and the 11 would be read as 1,100 pounds. See Figure 1.

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