232 
MESSRS. R, H. FOWLER AND C. N. H. LOCK ON 
We may notice also the peculiar behaviour of rounds III. (11-13), fig. 3,* in which 
the motion seems to become quite irregular from round to round after the first 
maximum yaw is attained. As these are the only rounds in which a yaw of 35 degrees 
or more is developed, it seems likely that some peculiar change in the type of the 
airflow occurs at or about this angle, analogous to the phenomenon of “ burbling. 5 
Rounds IV. (10-12) have the smallest velocity of any group fired ; the agreement 
of f M for these rounds with wind channel results for the whole range of S, figs. 1 and 2, 
is very satisfactory. 
The new values of/ M (v/a, 0) can be used to correct slightly the mean curves of/ M , 
and from the modified curves the value of / N , the coefficient of the force normal to 
the shell’s axis at small yaw, may be re-determined by the method used in (A), §1-13. 
The re-determined curve for f s is shown in fig. 1. The values differ only slightly from 
the former values, and the main features of the f s curve are fully confirmed. 
The final results of the complete experiment, stable and unstable rounds alike, 
corrected for the effect of the cards, have been combined together to give the final 
values of f u (v/a, 0) for shells of types I. and IV. and f y (v/a, 0) for type I. shown in 
Table I., which replaces the corresponding Table I. of (A). 
Table I.—Final values of f u (v/a, 0) and f s ( v/a , 0) for shells of type I. and/ M {v/a, 0) 
for shells of type IV., embodying the results of the whole experiment. The effect of 
the cards has been corrected for as far as possible, and this table supersedes Table I. 
of (A). 
v/a. 
Shells of type I. 
Type IV. 
/m (v/a, 0). 
/n (v/a, 0). 
/m (v/a, 0). 
Wind channel 
8-57 
3-34 
8-95 
0-7 
8-6 
3-35 
9-0 
0-8 
9-05 
4-0 
9-7 
0-9 
10-35 
5-2 
11-1 
1-0 
11-55 
5-25 
11-75 
1-1 
11-55 
4-7 
11-6 
1-2 
11-25 
3-9 
11-4 
1-3 
10-9 
3-7 
11-25 
1-4 
10-55 
3-85 
11-1 
1-5 
10-3 
4-0 
11-0 
1-6 
10-05 
4-15 
10-95 
1-7 
9-85 
4-3 
10-9 
1-8 
9-65 
4-5 
10-8 
1-9 
9-4 
10-75 
2-0 
9-15 
— 
* Also (A), p. 349, fig. 12 b. 
f This term is commonly applied to the sudden increase of turbulence behind an aerofoil at the critical 
angle. 
