8.
Tachymeter
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 TACHYMETER 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 TACHYMETER 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 TACHYMETER 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 TACHYMETER scale. The hourly
rate of this copier is
80
x
10
, or
800
copies.
NOTE - The scale is valid for all 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
.
Some of the following examples show ways to get
around this limitation.
7.2
60
TACH
YM
ET
ER
31
CHASE-DURER
P R O F E S S I O N A L
2 0 0 M E T E R S
60
40
20
10
30
50
T R A C K M A S T E R
10
8
2
4
6
9
3
12
6
9
3
12
6
TACH
YM
ET
ER
31
CHASE-DURER
P R O F E S S I O N A L
2 0 0 M E T E R S
60
40
20
10
30
50
T R A C K M A S T E R
10
8
2
4
6
9
3
12
6
9
3
12
6
A
START/STOP
A
START/STOP