THE AERODYNAMICS OF A SPINNING SHELL. 
317 
Table IY.—Showing Groups of Rounds Fired. 
The types of shell are numbered I.-IV., and the shells of each type are numbered 
1, 2, 3, ... in the order of firing.* 
Gun rifled one turn in 40 diameters of the bore. 
Group. 
Mean muzzle 
velocity for 
group, 
f.s. 
Remarks. 
Group. 
Mean muzzle 
velocity for 
group, 
f.s. 
Remarks. 
Type I. ; shells of form A 
centre of gnu 
dty normal. 
I. 11-14 
I. 8-10 
I. 17, 18 
I. 5- 7 
922 
1072 
1312 
1565 
1 
Stable 
Unstable 
Unstable 
Just stable 
I. 15,16 
I. 1-4 
I. 19 
I. 20,21 
2130 
2167 
2272 
2346 
Stable t 
Stable 
Stable 
Stable 
Type II. ; shells of form A ; centre of gravity forward. 
II. 8-10 
II. 11-13 
II. 14-16 
934 
1107 
1334 
Stable 
Unstable 
Unstable 
II. 5-7 
II. 1-4 
1585 
2024 
Stable 
Stable 
Type III.; shells of form A ; centre of gravity back. 
III. 8-10 
III. 11-13 
III. 14-16 
931 
1077 
1312 
Stable 
Unstable 
Unstable 
III. 5-7 
III. 1-4 
1583 
2025 
Just stable 
Stable 
Type IY.; shells of form B; centre of gravity normal. 
IV. 10-12 884 
IV. 7- 9 , 1553 
Very unstable 
Very unstable 
IV. 1-6 
2130 
Very unstable 
* Only the stable groups are analysed in this report. For a specimen yaw curve in an unstable case, 
see fig. 12. 
t Fired with cards on the far screens only, to determine by comparison the effect of the impacts on the 
cards. 
