Scale for 6 in radians 
348 MESSRS. R. H. FOWLER, E. G. GALLOP, C. N. H. LOCK AND H. W. RICHMOND: 
In drawing curves for <p against Qt it is necessary to resolve the ambiguities of 
amount 2mr as follows:—Equation (4.06), or fig. 11, shows that <f> increases hy 
-iOr 
30 *- 
20 - 
Fig. 12 a. Jump card trial, January and February, 1919. 
3-in. 20-cwt. gun with 16-lb. H.E. shell, Mark IIb. 
Shell, type I. Empty, and fitted with No. 80 fuze. 
The lower curves show the observed values of the yaw ( 8 ) on the 
scale 1 unit = 5° yaw, and the upper curves show the observed 
values of the orientation of the yaw (<£) on the scale 1 unit = 500°. 
Along the base are shown the values of Of in radians, on the scale 
1 unit = 10 radians, where t is the calculated time to each screen 
and 0 = AN/B, N being the axial spin of the shell in radians per 
second, and A, B being the axial and transverse moments of inertia 
respectively. The slope of the broken lines in the upper diagrams 
corresponds to the ratio <f >/0 = 
Those parts of the curves which are not determined by the obser¬ 
vations are also shown by broken lines. 
These diagrams show a typical example with each muzzle velocity 
used during the trial. 
Gun rifled V50 
Gun rifled t 4 o 
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(radians) 
|A 2 T± 7 t hi each period T, the increase of +1 occurring chiefly in the neighbourhood 
of the minimum, especially when is small. Hence, by adding to the observed <f> 
