Tachymetre, Start/stop – Chase-Durer Squadron Commander User Manual

Page 10

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8.

Tachymetre

More Examples:
Suppose you wanted to measure the speed of a jet airplane. After traveling 10 kilometers, you noted that 40
seconds had elapsed. The TACHYMETRE dial displays 90, but you traveled 10 kilometers, so the answer
would be 10 times that, or 900 km/hour.

You can also measure other things, like fuel consumption. Suppose a pound of fuel took 48 seconds to
burn. The chronograph second hand indicates on the TACHYMETRE dial that you are burning 75 pounds of
fuel per hour.

timed for 30 seconds produces 72 parts. Stopped at
the 30-second mark, the chronograph second hand
points to 120 on the TACHYMETRE scale; the
production rate of the machine is 120 x 72, or 8,640
parts per hour.

Example No. 4 – A manufacturing production line

Example No. 3 – A copier makes 10 copies in 45
seconds. The sweep second hand was thus stopped
at the 45-second mark, which coincides with the
figure 80 on the TACHYMETRE scale. The hourly
rate of this copier is 80 x 10, or 800 copies.

NOTE - The scale is valid for elapsed times from

seconds to

seconds. If the duration of the event is

outside this range, then the answer on the dial is not valid. Short durations of under eight seconds can be
extremely difficult to time accurately
. Some of the following examples show ways to get around this limitation.

4.8

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CHASE-DURER

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START/STOP

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START/STOP

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