Miscellaneous – Chase-Durer Fighter Command User Manual

Page 15

13.

Miscellaneous

At 68 F (20 C), sound travels at 344m or 376yds / 1,129ft per second in air at sea level.

Example: Sea level temp is

and

lightning to thunder measured time is 17.4
seconds. Distance of lightning strike point
is:

17.4s x 1,129ft = 19,644ft
17.4s x 376yds = 6,542yds
17.4s x 344m = 5,986meters
OR:
17.4s / 4.68s = 3.72 miles
17.4s / 2.66s = 6.54 thousand yards
17.4s / 2.91s = 5.98 kilometers

68 F

At 32

F (0

C), sound travels at 332m or 363yds /

1,089ft per second in air at sea level.

Therefore, at 32

F (0

C) sound will travel:

1 mile / 1,760 yards / 5,280 feet in
1,000 yards in
1 kilometer in

4.85 seconds
2.75 seconds
3.01 seconds

NOTE:

Therefore,

68 F (20 C) sound

1 mile (1,760 yards / 5,280 feet) in
1,000 yards in
1 kilometer in

To estimate the distance to an event (such as an
explosion, muzzle flash, lightning, etc.), measure
the time from the visual flash to the sound and
multiply the seconds by the per second speed.

For example the measured lightning to thunder
time at 68 F is 10 seconds. 10 x 344m or
376yds / 1,129ft would produce 3,440m or
3,760yds / 11,290ft. (2.14miles)

Alternately, you can divide the measured time at
68 F by 4.68 to get miles (10s / 4.68 = 2.14miles),
or 2.66 for thousand yard distance, or by 2.91 for
kilometers.

will travel:

4.68 seconds
2.66 seconds
2.91 seconds

CHASE-DURER

FIGHTER

COMMAND

ALARM

DATE

1/100 SEC

330 FEET

GENEVE