1g2 KANSAS UNIVERSITY QUARTERLY. 
21, hence the envelop curve is tangent to the load curves for loads 
and velocities as follows— 
OAS Crile 6) I 2 3 4 5 6 
Velocities (x) 5 Te EO Dd. OL 5 helena 20 
that is, for each increase of velocity of about 2} miles per hour, 
starting with 5 miles, there is an addition of one pound of load. 
é| H Hi 
7K 
ae / 
Lb L\ 
Sia 
1g 
cA oes eam] oe 
4 Za Li | 
1] 
<4 
Fi at 7 Wr — ah K] 
Bilge d 
Hence for this curve AK the relation between load and wind veloc- 
ity is, load z=-—-2-++2x (5) 
x being in miJes per hour and z in pounds. 
To find the relation between wind and velocity and velocity of 
wind wheel, v, for this curve we notice that y in (2) being, horse 
power is proportional to the product of the brake load and the 
velocity of the wind wheel or y==kvz, k being a constant. Substi- 
tuting for y this value in (2) we have 
WS 
x? ==25-+-345(k.v.z) (5) 
Substituting for z its value from (3) in (5) and reducing we have 
x?—-138kxv-+-690kv-—25==0 (6) 
Ideal curve AK. 
ee 
