ELASTIC RADIAL DEFORMATIONS OF FLYWHEELS. 295 
for bay F are shewn, the other bays not having been finished 
through press of time. This bay may be taken as repre- 
sentative, for trials of the centres of the other bays gave 
results similar to those shewn. 
Four-armed Wheel, straight arms, jointed midway 
between the arms.—The lower set of curves in fig. 22 shews 
the deflections at various speeds, of points in the bays A 
and OC, which contain the joint. The upper set of curves 
in fig. 23 shews the inflections at various speeds of points 
in the bays B and D, which do not contain the joint. It 
will be observed that the deflections in the jointed bays 
were very large, being caused both by the weakness of the 
joint and by the concentrated loading of the lugs. In 
order to separate these two effects, blocks of cast iron 
approximately equal to the weights of the flanges were 
bound by means of copper wire on the inside of the rim at 
the centres of bays B and D, and deflections taken as before. 
The deflections for bay C are shewn in the lower set of 
curves in fig. 23, and the inflections for bay B in the upper 
set on fig. 22. It will be observed that the deflections are 
lessened enormously, but are still very great—about four 
times as great as in the unjointed wheel. The inflection 
is also very much lessened. These effects will be seen 
clearly in fig. 24. 
Four-armed Wheel, straight arms, jointed along the 
arms.—The two opposite bays A and C were completely 
measured (see figs. 25 to 27). The joint lay along the arms 
AB and CD, so that the curves in fig. 25 represent the 
deflections of points adjacent to the jointed arms, and the 
curves in fig. 26 represent the deflections of points adjacent 
to the unjointed arms. From fig. 27 it will be seen that 
in both bays A and C, the deflection of the 78°75° 
position was less than that of the jointed arm, there being 
even a considerable inflection in bay A. The points on the 
