How to properly tune a recurve bow

Sighting with the Olympic recurve bow

Definitions

The inner visor image
It includes

  1. the front sight,
  2. the tendon
  3. and the aiming eye.
Ideally, in the final stage of tensioning, it will be static. This means that the position of the tendon in relation to the front sight does not change.

The visor image
The visor image includes

  1. the goal,
  2. the front sight,
  3. the tendon
  4. and the aiming eye.
All parts lie on a straight line, the end points of which are the target and the aiming eye. It is dynamic, the inner sight image ideally moves on a random, smooth loop curve over the target. How this curve looks in the real case with good shooters can be seen very nicely on the educational posters of the German Shooting Federation.

The holding surface
The area on the target that the inner sighting image sweeps over during the aiming process is called the holding area or holding space.

The attack
This describes the position of the pulling hand in the shooter's face at the end of the cocking process. Usually the term "anchor" is used. I avoid the term "anchor" because it suggests something static, and that is not what the stop is.

Weapon and sighting device

The weapon sends a projectile on its way and the sighting device is used to give the weapon the direction in azimuth (lateral angle) and elevation (elevation angle) so that the desired target can also be hit. In the case of pistols and rifles, the sighting device is rigidly connected to the weapon. This does not apply to the bow.

The stop in the shooter's face is responsible for the elevation, namely the vertical distance between the eye and the arrowhead. In addition, this stop is not static, but at the same time an axial movement has to be carried out in order to increase the pull-out distance by the Clicker to come. The position of the tendon in relation to the front sight is responsible for the azimuth.

The visor image

The aiming is only done consciously at the beginning, when the shooter points his weapon roughly at the target. If the sighting image is reasonably correct, the unconscious takes over most of the adjustment and coordination of the movements. It should be the fact that the unconscious (anticipation) "knows" the expected positions of the target image far ahead of the conscious and thus determines the course of time. These relationships are described in more detail in the article "Clicker, the attempt at modeling"
And here the algorithm of the entire shot sequence is shown

The sight picture should look like this:


Image 1

It is a "symbol picture" This applies to all other pictures in this article. The sizes are based on a sight tunnel of 8mm edge length or diameter, which is about 0.8m in front of the eye. The tendon should be black, 2mm in diameter and 7cm in front of the eye. The "target" corresponds approximately to the 80 cm WA support and stands at a distance of 50 m.

It is state of the art that the sights can be seen in focus and the target out of focus. The brain needs precise information about the position of the inner sight image in relation to the target in order to control the corresponding muscle groups correctly. More details can be found in the two articles "The clicker, attempt at modeling" and "Target Panic".

The next picture shows how, in the ideal case, the movement of the sight image is controlled by conscious and unconscious action in a very good shooter:

picture 2

The sharp "kink" when entering the holding surface shows the last "conscious" action of the shooter. The unconscious then controls the movements in such a way that smooth loop curves are traversed. The shooter concentrates on the sighting image and the cocking, the unconscious knows much more precisely (because it has about one second lead time) when the clicker will fall and the shot will be executed. These loop curves are shown very well on the educational posters of the German Shooting Federation. Incidentally, the teaching posters are actually curves driven, elaborately recorded by a laser.

The inner visor image

The inner sight image defined the position of the body in relation to the bow. If the stop in the face has remained the same ... The lateral position (azimuth) is, however, fixed by the tendon in relation to the front sight. You can turn your head around the vertical being controlled. What is not fixed by the sighting device is the elevation, which is specified by the distance between the arrow nock and the eye in the final extension. That is why the solid touch on the face is so important. As a first approximation, it has nothing to do with the visor image. The even stroke in the face (distance eye-arrowhead) can only be influenced by training. The lateral position can be influenced.

Round sight tunnelSquare sight tunnel

picture 3

If you turn your head around the vertical in the final extension and observe the sight image, you will notice that the position of the tendon in relation to the front sight can be shifted within wide limits. Of course, each position of the tendon has a different position of the hit on the target. In order to check the position of the tendon, two straight edges (one blurred, the other sharp) should be much easier to check than tangling a sharp circumference on a blurred edge. Where the tendon lies, whether to the left or right of the sight tunnel and whether there is a narrow gap between the sight tunnel and the tendon, is unimportant and depends on the shooter's taste. The sight itself must be constant, that goes without saying.

The effect of changing the sighting image is shown here.


Picture 4

Visor adjustment

Since the position of the line of sight is not permanently connected to the weapon, it will be necessary to adjust the sight over and over again due to slight changes in style. The question is always how much the change has to take place. Since the change in the trajectory is ultimately only very small, it is completely sufficient to proceed according to linear rules (theorem of rays). In the following rule, the distance between the eye and the front sight is assumed to be one meter.


Pic 5

Figure 5 shows the vertical and lateral offset of the target image. The middle meeting point is determined as follows:
You go with an imaginary, horizontal line from below (or from above) and count the hits that the line hits. Halfway through the hits, the height of the middle point of impact has been determined. You proceed in the same way with a vertical line from the left or right and get the side of the middle meeting point. It is not the exact mean meeting point, but the "central value". However, it is sufficiently precise for adjusting the visor.

The rule is:

CentiDekaMillimeter rule

The shelf on the support is in "Centimeter",
the range in "Dekameter and
the visor adjustment in "Millimeter
measured.

Example:
At a distance of 18m the side deflection is 5cm.
Therefore the visor has to be turned 5cm / 2*dam =2,5mm adjusted.
*) the 18m are generously rounded up to 20m = 2dam.

Of course, this also works the other way around:
If the sighting error shown in Figure 4 is 2mm, the hit is offset by 4cm to the side.

If you want to have it a little more precisely (but that's really hair-splitting (some people love to split hair ... laugh ...) then you can measure your eye-front sight distance, and the result of the sight adjustment with this length ( in meters!) This is also derived from the theorem of rays.

Focus

In Forum Archery Knowledge I was made aware of an error in the assessment of a video. The discussion revolved around the old topic, where should the shooter align sight and target when focusing, direct his absolute attention, the front sight or the target. My attitude is very clear, of course on the front sight, which has long been the standard for rifle and pistol shooters. The discussion gave me the idea to use a camera to understand what effects are to be expected.

The eye has a focal length of 17mm and a maximum aperture of around 1 / 5.6. I tried it with a DSLR Pentax k5 and a Sigma 1.8, 18-35mm lens to understand what effects it would have if it were used consistently performs. I took photos with my hand, f-stop 5.6, distance to the front sight 1.1m and to the target 10m. ISO 1600 sensitivity
An air pistol pad served as the target. Four recordings were made:
1. Sight sharp (distance camera-front sight 1.1m
2. Sight with distance adjustment 10m
3. Target sharp
4. Target out of focus with distance setting 1.1m.

The result was really amazing for me too. I had actually assumed that with this small focal length the effects couldn't be as strong
also because many shooters state that they just focus on the target ...

Here is the result when focusing on the goal:

The visor is far more blurred than I expected.

And here you can see when the focus is on the visor, which means that the visor is seen uncompromisingly sharp. The target is still very much in its true focus.

If it is really used consistently to see only the target in focus, you will make a lot of mistakes through the blurred sight. That means in reality the shooter will always have to mentally jump between target and sight. I don't think that's a good solution.

The photos were Not post-processed

Final remark

In this short summary, the attempt was made to describe aiming with the Olympic recurve bow as briefly and as clearly as possible. Anyone looking for the tendon shadow here was of course disappointed. I recommend taking a close look at the arch resting on its arch stand and the ground below in the summer sunshine. The tendon shadow will surely be found on the floor.
This expression was created in the last century by a technically inexperienced German bow "sportler". It doesn't exist in English. There, what is said in this article about the position of the tendon in the sighting image is sober and correct: "string alignment".

Like everything on my website, I own the copyright to this article. The use of this article for further training in the association is permitted without making copies.