Some Remarks on the Trajectory and the Rotary Motion of Arrows
The York Round demands of the archer close attention to the rules governing the flight of his arrows.
The trajectory of an arrow is low or high according to the power of the bow and the perfection of the bowman's loose, and is a parabola similar to the line of a rifle ball's flight.
A low trajectory is very desirable in shooting at long range. To secure this, many fine archers ruin their scores by using a bow too strong for their muscles.
The best way to secure a low flight is to perfect yourself in loosing, and to use a bow well suited to your strength.
Mr. H. A. Ford, the celebrated English archer, whose score at the Double York Round of 1251 has never been equaled, is said to have ruined the tendons of his drawing fingers by the use of a 57 pound bow, though he was a very tall and exceedingly powerful man.
The use of light arrows with very narrow feathers will lower the trajectory; but to go to the extreme in this direction will put you in danger of breaking your shafts, and cause you great trouble in windy weather from irregular drifting. A 4.6. arrow with a 48 pound bow, and a 4.9. arrow with a 50 to 54 pound bow, will be found about right.
Nothing affects the trajectory more than to hold the bow full drawn too long before loosing. A 60 pound bow held two seconds at a full draw, will not cast as low an arrow with the same elevation as a 49 pound bow loosed instantly and smoothly.
It might seem that in order to give an arrow the rotary motion of a rifle-ball it would be necessary to put the feathers on spirally. We have seen this done, but it is a mistake. Arrows made after the ordinary English style, with feathers practically parallel to the stele of the arrow, we have found to have a very rapid rotary motion This happened to be demonstrated in our presence as follows: An arrow was shot into a target distant 100 yards, and chanced to touch a long iron spike which projected from the rude target easel we were using. This spike had a very sharp corner which cut a groove in the stele of the arrow as it passed, which groove, upon examination, was found to run spirally around the shaft three times in six inches, or once in two inches. Now, an arrow shot with the full force of a 52 pound bow will fly 100 yards in about two seconds. There are 3600 inches in 100 yards. Therefore, if an arrow flies 3600 inches in two seconds and turns once in two inches, it will turn 900 times in a second, a pretty rapid rotation. Of course, it starts with a much greater velocity. The average would probably be at least I 200 revolutions in a second.
If the pile of an arrow is too tapering, the trajectory will be high; if almost parallel-sided, the trajectory will be low. Any injury to the feather is likely to make the trajectory high. If the point of an arrow gets truncated by striking a stone or other hard substance, its trajectory will probably be lower than before, but it will rebound from the target. Nothing is better settled than that a truncated missile will fly further than a sharp or pointed one. Therefore, an arrow should have a straight, parallel-sided pile, with a very steep slant to the point, if you wish a low trajectory.
For directions in regard to repairing arrows when injured, and for making hunting bows and arrows, see "WITCHERY OF ARCHERY."