The value 
of the co¬ 
efficient K 
varies at 
different 
velocities. 
Explana¬ 
tion and 
use of the 
Table of 
Values of 
the Coeffis 
cient K. 
244 
PRINCIPLES OP GUNNERY. 
Thus v = 
1364 
1 + 
108*5 
(1000) 3 
= 1317 f.s. 
X *24 X 1364 x 1000 
By the use of Bashfortlds Distance and Velocity Table (vide p. 250) 
calculations of this kind are much simplified. 
The value of K, however, cannot be taken as constant for large varia¬ 
tions in velocity; so that it becomes necessary to tabulate the value of 
K for all practical velocities. 
Up to the present time the value of this coefficient has been accu¬ 
rately determined for velocities varying from 1700 f.s. to 900 f.s. for 
ogival-headed projectiles. Experiments are now in contemplation to 
determine it for the lower velocities used in curved or indirect fire. 
Table showing the Values of K corresponding to Velocities at Intervals of 10 ft. 
per second. Elongated shot , ogival head* 
Velocity. 
Value 
of K. 
Velocity. 
Value 
of K. 
Velocity. 
Value 
of K. 
Velocity. 
Value 
‘ of K. 
f.s. 
f.s. 
f.s. 
f.s. 
900 . 
64-4 
1110 . 
106-6 
1310 . 
107-7 
1510 
96-4 
910 . 
64-8 
1120 . 
107-1 
1320 . 
107-4 
1520 . 
95-5 
920 . 
65-3 
1130 . 
107-5 
1330 . 
107-1 
1530 . 
94-7 
930 ...... 
65-9 
1140 . 
107-9 
1340 . 
106-8 
1540 . 
93-8 
940 . 
66-6 
1150 . 
108-2 
1350 . 
106-4 
1550 . 
93-0 
950 . 
67-4 
1160 . 
108-5 
1360 . 
106-0 
1560 . 
92-2 
960 . 
68*4 
1170 . 
108-7 
1370 . 
105-6 
1570 . 
91-4 
970 . 
69-6 
1180 . 
108-9 
1380 . 
105-1 
1580 . 
90-6 
980 . 
71-0 
1190 . 
108-9 
1390 . 
104-6 
1590 . 
89-8 
990 . 
72-8 
1200 . 
108-9 
1400 . 
104-0 
1600 . 
89-0 
1000 . 
75-0 
1210 . 
108-9 
1410 ...... 
103-4 
1610 . 
88-2 
1010 . 
77-5 
1220 . 
108-9 
1420 . 
102-8 
1620 . 
87-4 
1020 . 
80-4 
1230 . 
108-8 
1430 . 
102-2 
1630 . 
86 7 
1030 . 
83-9 
1240 . 
108-8 
1440 . 
101-6 
1640 . 
86-0 
1040 . 
88-2 
1250 . 
108-7 
1450 . 
100-9 
1650 . 
85-4 
1050 . 
92-8 
1260 . 
108-6 
1460 . 
100-2 
1660 ,. 
85-0 
1060 . 
97-2 
1270 ...... 
108-5 
1470 . 
99-4 
1670 . 
84-6 
1070 . 
100-8 
1280 . 
108-3 
1480 . 
98-7 
1680 . 
84-3 
1080 . 
103-4 
1290 . 
108-1 
1490 . 
97-9 
1690 . 
841 
1090 . 
1100 . 
105- 1 
106- 0 
1300 . 
107-9 
1500 . 
97-2 
1700 . 
83-9 
N.B.—In the above table a cubic foot of dry air is supposed to weigh 530’6 grs., which corresponds to the 
barometer at 30'0ins. and thermometer at 65 - 5° F. The value of K varies as the density of the air, but it is 
calculated at a standard density on the above supposition. 
Suppose the value of the coefficient K be required for a velocity of 
1600 f.s.: opposite to 1600 in the velocity column, K— 89'0. 
Example. —What is the resistance of the air in lbs. to an ogival¬ 
headed projectile of 16 ins. in diameter, moving with a velocity of 
1600 f.s.'? 
From equation (1) 
d 2 
9 
R 
-K—-( 
V 
Vioooy 
Y = 89x(16) »/1600Y= 889 81ba . 
32-19 \10007 
4 Vide p. 152, “ Report on Experiments made with the Bashforth Chronograph to determine 
the Resistance of the Air to the Motion of Projectiles.” 
