ARROW ALIGNMENT AND TUNING

Arrow alignment is defined as the angle, in the horizontal plane, between the direction the arrow is pointing and the plane of the bow at the moment the arrow exits the string. The direction the arrow is pointing is defined as the line linking the two shaft nodal points.

Re the diagram looking down on the arrow, for a RH archer, the blue arrow is regarded as positive alignment angle and the red arrow a negative alignment angle.(in reality the arrows are bent around the riser, not straight lines).

As reviewed elsewhere, on its own the arrow alignment at launch is fairly irrelevant to "tuning" and makes a neglible change to the overall arrow direction. However when you couple together the initial arrow alignment and the arrow rotation the arrow alignment does make a significant difference to the arrow flight behaviour.

For example it's easy to see that if the arrow was launched, rotating say in a clockwise direction, then the rotation and stabilisation of the arrow would be different if the arrow was launched at an initial clockwise angle as opposed to an initial anti-clockwise angle.

The consequence is that the results of say a 30 meter bare shaft tuning, in terms of group sizes, will be different with a negative, zero or positive initial launch angle. Having a zero initial launch angle will give the best result.

Suggested here is methodology for checking the arrow launch angle and to some extent correcting for its effects potentially reducing group sizes. This is a purely armchair theory and has never had any practical test. Practical testing is required to determine whether there is anything to the theory and if so to turn it into a practical method.

In the following it is assumed that the initial bare shaft tuning setup is made by crossing the bare shaft across the fletched shaft with the final button spring setting splitting the difference between these two points.

Suggested Procedure

• Carry out a normal 30 meter bare shaft tuning process
• Without changing anything except the vertical sight position shoot both fletched and barshaft arrows at the target at 50 to 60 meters distance.
  • If the fletched and bare shaft arrows are centered on the target then the initial launch angle is zero.
  • If the arrows fly left of center than the initial launch angle is negative.
  • If the arrows fly right of center the initial launch angle is positive.
• If the launch angle is zero then no further action required
• if the launch angle is not zero then one of following actions:
  • If the fletched arrow group is at a measureable distance sideways from centre then move the fletched arrow group to the center with the button spring.
  • If the fletched arrow group appears central but the bare shaft arrows are displaced laterally move the bare shaft arrows to the center with the button spring.

Ideally a mechanism to change the launch angle is what's wanted. Possible changing the center shot or brace height would do this, but any such methodology would only be determined by practical testing.

The following extract (from archery-interchange.net 14 January 2012) provides one archer's practical description of the alignment process

....during a phase of messing about about I tried to obtain nodal alignment from the initial departure of the arrow from the bow and at 10 and 20 yds and I sort of achieved it (based on locating nodal points on a bare shaft by methods established by Olympians and coaches from the 80's which coincided with positions obtained from a homemade "exciter" to oscillate an arrow) marking these nodes with chalk pastel crayons and shooting through paper, made GMB for the 1st time that year...
.....Well it was after reading McKinney's book, he said something along the lines that once you get your alignment right that the bare shafts will impact with the group but much straighter and also that wind drift would be reduced that I investigated further, he did describe some method of moving the plunger depth depending on which way the nock of the arrow was seen in relation to the point at the moment of loose, but I couldn't see it, so I thought up the chalk/pastel trick, and yes I observed straighter bare shafts and less wind drift (subjective??) and the winner...better groups...
Blobs of chalk residue were in contact with each though not on top of one another which was the objective, tears were horizontal (which confirmed nock point height was correct to me) and about 1¼" long, point impacts were as expected in different positions (could see distinct embossing that could only have been made by the point).......
Had to make adjustments to the brace height too, plunger depth adjustments had to be compensated with tension adjustments to maintain central impact position in relation to point of aim.....
...Was not worried about length of tear as depending on how arrow is in its bending cycle at the time as it passes through the paper it could be a bullet hole or about three inches long and that can be the case by just moving the paper back 2", (that's why reading purely the tears and trying to obtain bullet holes at various distances during shooting through paper is a waste of time for recurve).....

New 15 January 2012