FORCES OF OBLIQUE WINDS ON TELEPHONE WIRES 599 



wind velocity when a equals 50° ranges from 0.00265 to 0.00850 pound 

 per foot of wire for a range of velocities from 30 to 90 m.p.h. In the 

 case of 0.165-inch wire and an angle {a) of 60° the variation ranges 

 from 0.00254 to 0.00969 pound per foot of wire for the same range of 

 velocities. As mentioned above the frame in which the wires were 



O 0.006 



K 0.005 



O 0.004 



30 40 50 60 



ANGLE a IN DEGREES 



Fig. 8 — Graphic relation between the wind force along the wire (tangential- 7^() and 

 the angle (a) of wind direction from normal — 0.165-inch diameter wire. 



tested comprised such a major portion of the total resistance when the 

 angle a approached 90° or the wind and wires were about parallel 

 that the data for these cases were not considered reliable. In plotting 

 the curves in Figs. 7 (0.104-inch wire) and 8 (0.165-inch wire) the 

 tangential force for 90° was estimated and to indicate this the curves 

 are dotted between the angles a. of 80° and 90°. 



