Slide Rule, which literally means slide rule, generally refers to two scales sliding relative to each other to measure or calculate. So Slide Rule is also called slide rule. Specifically for Breitling, the Slide Rule for Pilot, which was first applied to watches in 1942, is a very unique feature of this brand watch, and it is also widely used. Let’s take a look at how to use this feature.

The basic principle of the flying slide rule is very simple, which is to simply calculate the multiplication and division by the relative rotation of the inner and outer scale circles. From this, many practical functions are derived, such as unit conversion, ground speed calculation, fuel consumption, climb rate, and so on.

Fundamental

Let us first understand the most basic multiplication and division.

Multiplication

Multiplying AxB: Rotate the outer ring scale A to the position corresponding to the inner ring scale 10. At this time, the value of the outer ring corresponding to the inner ring scale B is the result of AxB. For example, calculate 13×7: Rotate the outer ring so that the scale 13 corresponds to the position of the inner ring 10. At this time, the outer ring scale corresponding to the inner circle scale 7 is 91, which represents 13×7 = 91.

Division

Division calculation A ÷ B: Rotate the outer ring scale A to the position corresponding to the inner ring scale B. At this time, the outer ring value corresponding to the inner ring scale 10 is the result of A ÷ B. For example, calculate 12 ÷ 8: rotate the outer ring so that the scale 12 corresponds to the position of the inner ring 8. At this time, the scale of the outer ring corresponding to the scale 10 of the inner ring is 15, which represents 12 ÷ 8 = 1.5.

Involving three-digit operations

Because the maximum scale of the slide rule is 99, when using a flying ruler for calculations, if there are three digits, errors are easy to occur. A small scale between two integer scales is used. For example, calculate 132×7. Align the 13.2 scale of the outer circle (the first minute scale to the right of the 13 scale) with the 10 scale of the inner circle. At this time, the 7 scale of the inner circle corresponds to the outer circle between 92 and 93, indicating that the result is 920 to 930. In between, the actual is 924. So by dividing the scale, you can perform more digit calculations.

Practical application

Based on these basic principles, we can perform many practical operations.

First, the unit conversion

1.MPH and KPH conversion

Conversion of MPH to KPH

The conversion factor between miles per hour and kilometers per hour is approximately 1.6, which is 1MPH = 1.6KPH. Then rotate the 16 scale of the outer circle to the 10 scale of the inner circle, and the inner circle represents MPH, and the corresponding outer circle number is the result of converting MPH to KPH. For example, 10MPH = 16KPH and 60MPH = 96KPH.

2.MPH to MPM

MPH to MPM Conversion

If you need to convert MPH miles per hour to MPM miles per minute, you can also use the flying slider. For example, convert 156MPH to MPM, and rotate the outer ring scale of 15.6 to the MPH mark at 12 o’clock in the inner ring. At this time, the 10 scale of the inner ring corresponds to 26 of the outer ring, which represents 156MPH = 2.6MPM.

Second, speed time distance calculation

1.Speed calculation

Computing speed

After measuring the time required to pass a distance through the timing function, you can calculate the average speed of that distance. For example, using milestones on the road and measuring the time of 45 miles with the timing function is 30 minutes, then the 45 scale on the outer circle is aligned with the 30 scale on the inner circle. 90 means an average speed of 90 MPH, and kilometers are also applicable.

2.Time calculation

Time calculation (more than 1 minute)

When the required calculation time is longer (more than 1 minute), the time can be calculated as follows. With a known speed of 156 MPH, the time required to calculate the form is 486 miles. Align the outer ring 15.6 with the inner ring MPH mark. At this time, the inner ring scale corresponding to the outer ring 48.6 is 18.7, which means it takes 187 minutes.

Time calculation (within 1 minute)

When speed is large and distance is short, the time required is usually measured in seconds. In this case, another calculation method is needed. For example, how long does it take to travel 1.5 miles at 120MPH? Align the 12 scale of the outer ring with the 36 scale of the inner ring (starting from the second, originating from 3600 seconds per hour). At this time, the scale of the inner ring corresponding to 15 is 45, which means it takes 45 seconds.

3.Distance calculation

Distance calculation

Known speed is 148MPH, calculate 28 minutes driving distance. Align the 60 scale of the outer ring with the 14.8 scale of the inner ring. At this time, the 28 of the outer ring corresponds to the inner ring scale of 6.9, which represents a driving distance of 69 miles.

It should be noted that the calculation of speed and time uses division, so the speed and distance values are reflected by the outer scale, and the time values are reflected by the inner scale. In contrast, the distance is calculated as multiplication, so the speed and distance values are reflected by the inner scale, and the time values are reflected by the outer scale.

For the same reason, you can also calculate each other between the fuel consumption rate, sailing time and fuel consumption through the flight slider. At the same time, you can calculate each other among the climb / descent rate, climb / descent time, and climb / descent distance. For further information, you can refer to Breitling’s official instruction manual.