BOWS AND ARROWS — KLOPSTEG 



589 



lao 



MASS-VEUOCITY RELATIONSHIP 



OP ARROWS 



BOW: OSAGE ORAr4G£, 1000 FT.- POLS. 



SOLID CURVE, COMPUTED 

 MEASURED VALUES » X 



2 SO 



32S 



MASS OF ARROW, GRASNS 



'^OO «575 ^O 



62S 



Figure 9. — Relation between mass of an arrow and its velocity when shot from a bow having 

 1,000 foot-poundals of available energy at full draw. 



ments to be uniquely characteristic of tlie bow. In bows of high 

 efficiency, i.e., of high energy transfer, K is small, and vice versa. The 

 \artual mass of a longbow is large. It is much smaller in the "scien- 

 tific" and the modem bows. This is the more readily understood when 

 we consider that the limbs of a bow must themselves be accelerated 

 by the stored energy in order to impart acceleration to the arrow. The 

 long, heavy limbs of the longbow are sluggish as compared with the 

 shorter and lighter limbs of its successors. Were it possible to trans- 

 fer all the energy in the bow to the arrow, the virtual mass of the 

 bow would be zero. Theoretically this might be achieved if a bow 

 could be so designed that the limbs had zero velocity in the normal 

 braced position at the instant of disengagement of the arrow. This 

 is an unattainable ideal, but it has been approached to within 10 

 percent. 



In closing this discussion, it is my hope that the purposes set forth 

 at its beginning have been achieved. More detailed exposition of the 

 many technical considerations involved in the design, construction 



