nN 
for) 
— me pw NO 
i=) 
i) 
o _ @ 
—24 
Arm. 11°25 22°5 Bh we) 45° 56°25 67°5 78°75 Arm 
Position on Rim. 
Fig. 19—Four Armed Wheel—Curved Arms. Curves shewing deform-- 
ation of Bays at various speeds. 
No.1. Bay B, 18 revolutions per second No.7. Bay A, 18 revolutions per second 
39 2 9 16 ” be) 9) 8. 9 16 39 39 
33 3. 39 14 99 33 33 9. 3) 14 33 33 
9 4. 39 12 ” ” ” 10. 99 12 i) 3° 
ed 5. 33 10 9” +” 39 a. 33 10 3) 33 
99 6 3) 8 33 2” 9 12. 3 8 39 33 
deflections being 6% less in magnitude. The arms were 
designed as regards their curvature according to Unwin’s 
‘*‘ Machine Design,”’ part 1, p. 397. The section of the 
arms was uniform throughout for simplicity, and was 
approximately the same as that of the straight armed 
wheels. They of course tend to straighten as the rim 
expands and are therefore subjected to cross breaking. 
The arms are much stiffer relatively to the rim than would - 
be the case in practice, and therefore cause much more 
relative bending of the rim. - | 
Six-armed Wheel, straight arms.—Curves for the six-_ 
armed wheel are represented in figs. 20and 21. Only those . 
