Why is the Breitling Navitimer a pilot’s watch? What is the Navitimer slide rule? What is a tachymeter? How do you cheat on the SAT test? Hopefully this blog will give you the answers to all of these questions. What many people don’t realize, is that Breitling’s Navitimer is capable of calculating all mathematical calculations a pilot needs while in flight. If you do not believe me, check it out. Hopefully this does not give you a headache…

**MULTIPLICATION & DIVISION **

Example 1

To multiply 8 x 13, position the number 13 on the outer scale next to the 10 marker on the inner scale. The answer, 104 (=10.4), will appear opposite the number 8 on the inner scale. This method works for all numbers. The user can also read 7 x 13, 9 x 13, etc.

Example 2

To divide 180 / 6, position the number 18 (=180) on the outer scale next to the number 60 (=6). The answer, 30, is found opposite the number 10 on the inner scale. This method works for all numbers.

**GROUND SPEED**

Example 3

**Known:** Distance and Speed **Unknown:** Time

A pilot wants to know how long it will take to travel 420km at a speed of 110km per hour. (measurements can be km or miles)

Position the number 11 (=110) on the outer scale next to the mph mark on the inner scale. The answer, 23 minutes, appears opposite the number 42 (=420) on the outer scale.

**KILOMETERS (OR MILES) PER MINUTE**

Example 4

In example 3, the speed was 110km (or miles) per hour. What is the equivalent of this speed in km (or miles) per minute?

Position the number 11 (=110) on the outer scale next to the mph marker on the inner scale. The answer, 1.83km (=18.3 miles) per minute is found opposite the 10 maker on the inner scale.

**TIME NEEDED TO COVER A SHORT DISTANCE**

Example 5

**Known:** km (or miles) per hour and distance **Unknown: **Number of seconds needed to cover distance

A pilot is nearing an airport at a speed of 150km per hour. This distance between a certain point at the airport and the end of the runway is 1.2km. The pilot needs to know the number of seconds that will elapse from the moment he has passed the airport until he reaches the end of the runway.

Position the number 15 (=150) on the outer scale next to the seconds mark, number 36, on the inner scale. The answer, 28.7 seconds can be found opposite the number 12 (=1.2) on the outer scale.

**FUEL CONSUMPTION**

Example 6

* The Navitimer slide rule can be used to solve any problem related to fuel consumption, provided two of the three pieces of information are available: Number of liters (or gallons) used, time, rate of consumption.

**Known: **Time and rate of fuel consumption **Unknown: **Number of liters (or gallons) of fuel used

A pilot wants to know how many liters (or gallons) of fuel are needed to fly for 5 hours when the average rate of consumption is 10.5 liters (or gallons) per hour.

Position the number 10.5 on the outer scale next to the mph marker on the inner scale. The answer, 52.5 liters (or gallons) appears opposite the number 30 (=300 minutes) on the inner scale.

**RATE OF CLIMB OR DESCENT **

Example 7

* The Navitimer slide rule can be used to solve any problems related to the rate of climb or descent when two of the three properties are known: Altitude (in relation to the starting point), time and rate of climb or decent.

**Known:** Rate of climb and altitude **Inconnu:** Time

A pilot climbs to 6,200ft. (or meters) above his starting point at a rate of 400ft. (or meters) per minute. How long will this take him?

Position the number 40 (=400) on the outer scale next to the 10 marker on the inner scale. The answer, approximately 15.4 minutes, is found opposite the number 62 (=6,200) on the outer scale. The user can also read the complete table of the time it takes to ascend to any altitude.

**DISTANCE REQUIRED FOR CLIMB OR DESCENT**

Example 8

* The Navitimer slide rule can be used to solve and problem related to the distance required for a climb or descent when two of the following pieces of information are available: Distance, time, speed.

The pilot from example 7 wants to know how far he will have traveled when his climb is finished. His speed was 120km (or miles) per hour and he has a tailwind of 20km (or miles) per hour.

Position the number 14 (=140 or 120+20) on the outer scale opposite the mph marker on the inner scale. The answer, 37km (or miles) appears opposite the number 15.4 (the answer in minutes from example 7) on the inner scale.

**CONVERSION OF STATUTE MILES, NAUTICAL MILES, AND KILOMETERS**

Example 9

* The Navitimer slide rule’s inner scale has three additional markers for units, besides the mph marks. Naut for nautical miles (knots), stat for statute miles, and km for kilometers. The conversion of nautical miles to statute miles or kilometers can be read on the outer scale.

**Known: **50 statue miles** Inconnu:** Equivalent in nautical miles or kilometers

Position the number 50 on the outer scale on the stat mark on the inner scale. In nautical miles, the answer is 44, can be found opposite the naut mark on the inner scale. The answer in kilometers, 81, is found opposite of the km marker on the inner scale.

**EXCHANGE RATES**

Example 10

* The Navitimer slide rule can also be used to solve conversion problems useful to everyday life. For example, exchanges between two currencies.

What are the exchange rates between currencies A and B, given that 1 A = 1.5 B?

Position the number 15 (=1.5) on the outer scale next to the 10 marker on the inner scale. The inner scale then represents the amounts in currency A and the outer scale, the currency B.

A = 12 B = 18, A= 7 B = 10.5, etc

Check out “A Flight Computer For The Wrist” in Breitling The Book to verify the validity of these calculations!!!

Whether pilots actually use the Navitimer for these calculations is up for debate. The fact of the matter is that they are capable of completing them if they know how to properly use their timepiece; that is pretty impressive if you ask me. Meanwhile, a high school student could easily use a Navitimer to perform various calculations needed to answer some mathematical questions on the SAT. I would recommend, however, that they use a calculator…I think it would save them some much needed time…