The straight flying arrow: tuning with the bare shaft.
As we consider what we hope to accomplish in fine-tuning, there is only one noteworthy thing to work toward on the equipment side of archery. We must tune the bow/arrow setup so that arrows consistently leave the bow straight. That is to say, the arrows will consistently come out with their axis straight in line with the direction it is traveling, which will be in the direction the bow is pointing. More simply put, it follows the same line to the target as the string and limbs are traveling. I realize the arrow will be flexing or oscillating when it first leaves the bow. However, it should be flexing on a straight path in the direction the bow is pointing. When the paradox has ended, the arrow's shaft should be pointing straight toward the direction of travel.
If the arrow leaves the bow askew to the direction it is traveling and the fletching has to move the shaft back and forth to correct it, then the shaft may no longer be headed exactly toward the point it was shot at. A shaft that leaves the bow crooked, to any degree, will wobble as the fletching corrects it. An arrow that wobbles, even slightly, will lose energy in flight. On the other hand, an arrow that leaves the bow perfectly straight will have all the kinetic energy pushing right behind the point. Also, if the fletching has to move the shaft back and forth, it will cost your arrow velocity. The fletching should not have to move the arrow around to straighten it. The fletching's only job should be to keep the shaft straight after it starts out on its perfect line.
With different bow models and with all your efforts and trials in tweaking for accuracy, all you can hope for (all you should hope for) is that arrows leave the bow straight. That is unless you want to tune for the alternative, which would be to tune for the arrows to leave your bow crooked and let the fletching work the shafts back and forth to correct them. I don't believe this should be anyone's goal in tuning.
Before you can tune to straighten the arrow's flight, you must be able to tell if the arrows are leaving the bow straight, and to what degree. Also, you must know when they are straightened out.
Most archers use a paper test to determine the course of a flying arrow. I do not believe this method always gives a true reading. As a matter of fact, I know it does not because at different distances we sometimes get different readings from paper tuning using the same setup.
Let's assume the string nock locator is too high. This will in turn cause the arrow to leave the bow with its tail end higher than the point. If the arrow leaves the bow "tail high," say two to three inches, what will happen? The fletching will meet a lot of resistance from the air. This sudden air resistance will force the fletched end of the arrow down, not just to the point of perfectly straight, but past that point. The tail end of the shaft will then, for a short time be lower than the front of the shaft. This overcompensation and correcting will continue getting less as the arrow moves forward until the fletching has straightened the shaft. Understanding this concept, it should be easy for you to see how this could give us the wrong reading while paper tuning. If the rear end of the arrows hits the paper on its rebound from being whipped downward by air resistance, it will make a low tear. This low tear would give the shooter a false reading that the shaft left the bow nock low, when the opposite is true. The same could be true if the arrow leaves the bow tail left or right.
If the arrow leaves the bow extremely crooked, the correction and over compensation may still be taking place several yards downrange. This is why you can sometimes see your arrows wobble, either side to side, up and down or in a circular pattern. Even if it's not to the degree that it takes place long enough for you to see, it doesn't mean this has not taken place. The only way not to have arrows wobble is to tune your arrows to exit the bow straight.
So what is the answer? How can you tell if your arrows are leaving the bow pointing straight toward the direction of travel? The best way I have found is to shoot an arrow without any fletching to see how it hits the target. With no fletching to straighten the arrow, the further it travels the more it will turn in the direction is started out. In essence, bare shaft shooting is the best way to find out how your arrows are leaving the bow.
If you can, tune your bow/arrow setup so a bare shaft will fly straight into the target. Then it is leaving the bow straight in line with the direction it is traveling. Your fletched arrows will also be coming out from the bow straight; provided of course there is no fletching contact to bump them off course. When you have the bow tuned so the arrows leave the bow straight, the fletching will not be forced to affect flight. Then, all the fletching will have to do is keep the shaft on its original course. Once the bow is tuned so that arrows leave the bow straight, you can put the issue of tuning to rest because there is nothing else to do to make the system more accurate.
There are other advantages to tuning arrows to leave the bow on a straight path. If the arrow leaves the bow cockeyed and air resistance on the fletching has to move the shaft back and forth to straighten it, you will lose penetration. This is a result of the loss of arrow speed and also because the shaft will cause resistance by not entering in line with the point.
Accuracy, speed and penetration are not the only benefits to be gained by tuning for straight arrow flight. Have you ever wondered why some archer's broadheads don't impact the target at the same place as their field points? It's because their arrows are not coming out of the bow straight. A broadhead, having a larger surface than a field point, will fight the fletching as the arrow leaves the bow for steering control. This causes the arrow to plane in the direction that it faces as it leaves the bow. This is also why longer fletching and a helical orientation are important to good broadhead flight.
Bare shaft tuning may sound intimidating at first, but it isn't that difficult. I have for many years shot the 20-yard indoor round with four fletched arrows and one bare shaft, with the bare shaft not adversely affecting my groups. I have done this with both recurve and compound bows. Also, my bows are tuned so that I can shoot bare shafts straight into the target at 50 yards, with the bare shafts grouping within a few inches of each other and my fletched arrows. If I can tune my bows to do this, anyone can learn to bare shaft tune to a degree that will improve their speed, accuracy and penetration.
Before you begin bare shaft or any fine-tuning you should complete the basic bow tuning adjustments such as tiller, timing (on one cam, two cam or eccentric wheel bows), center shot, and the location of the string nocking point locator. You don't have to go overboard trying to get these basic adjustments perfect. I am sure most bows are setup well enough to start bare shaft tuning.
First, we need to remove the fletching from a couple of arrows. Do not use arrows that you have discarded because they didn't group well. It is very important that you use "good" arrows. Also do not put broadheads on your bare shafts. Use field points that are the same weight as your broadhead.
As you start shooting, it doesn't make a difference whether you tune the shafts to enter straight into the backstop or to group with the fletched arrows. When you have one accomplished you will notice you also have the other. I will describe here how to tune to get the arrows entering straight into the backstop, because I believe that is the quickest and easiest way to bare shaft tune and also because it is what we want to achieve.
When you begin shooting start out no further away from the backstop than five or six yards. If your shaft is crooked coming out of the bow, it will catch so much air that it will dart off and may miss the backstop if you start shooting from too far away.
After you have the basic tuning completed and your bow setup for hunting, move to about five yards from the backstop and shoot the bare shafts into the target. Without moving from your stance, notice how the shafts are sticking into the backstop. If the shafts are not sticking straight in, then they didn't leave the bow straight with the direction of travel and you will need to do some adjusting. Keep in mind you can get a false reading due to the consistency of your backstop material. Be sure to repeat this test a few times and look for a consistent result.
You will need to start by tuning for low or high arrow nocks. Looking at the shafts from where you shot, if the shaft's nock ends are lower than the location where they entered the backstop, then your shafts are leaving the bow rear end low. To adjust this, move the string nock locator up the string or you can lower the arrow rest. Either adjustment will have the same affect. Try to keep the center of the shaft running through the middle of the arrow rest hole in the bow's riser up to the upper one-third of the hole.
If the shaft's nock end is higher than the entry hole, the string nock locator will need to be lowered to correct this. If the shaft's nock ends are too high in the backstop, adjust in the opposite direction. Note: If your string nock locator is a bit too low, the nock end of your shaft may kick up off the rest causing the nock end to be high in the target butt. This will give a false indication that your string nock locator is too high. Be aware of this so it will not confuse you. Adjust the string nock locator up and down the string until the shafts are leaving the bow with the rear end neither high nor low, but straight.
Next, you need to adjust for the shafts leaving the bow with the rear or nock end to the right or left. If the shaft's nock ends are to the right or left of the entry hole, you will need to adjust the bow cast to arrow spine difference. Changing your arrow's point weight (or cutting a small amount off of the shafts) may correct the problem (this changes your arrow's spine slightly). However, if this is not sufficient, it may become necessary to change your bow's draw weight or change to different arrows.
If you have a problem with your arrow leaving the bow tail right or left, most of the time you will find that your arrow is under spine. Whether an under spined arrow leaves the bow tail left or right depends on your bow's brace height, therefore you will need to do some experimenting if you have tail right or left arrows to decide how to correct it. The quickest way to figure this out is to adjust the draw weight of your bow. First, decrease the draw weight. If that does not correct the problem, or makes it worse, try increasing the draw weight. By experimenting in this manner you can quickly find out if your arrows are under or over spine for your bow's cast.
After you have your shafts entering straight into the backstop at five or six yards, move back and shoot at 20 yards. You may now see that you need to do some fine-tuning. If your shafts were a little off up close, it will be more noticeable at 20 yards. (With no fletching to correct your shafts, the further they travel, the more they will turn in the direction they started off.) Note: At 20 yards you should not tune for the height of the arrow nock to be exactly the same height as the arrow's entry hole. Because the field point is heavy and there is no fletching to raise it, the point will gradually pull the front end of the shaft down. If your string nock locator is correct, the entry hole will be lower than the shaft's nock by two inches or so at around 20 yards.
While you are tuning the bare shafts you may notice that the problem of a high or low nock is easier to get correct than is the right/left nock, especially if you shoot a bow with a low brace height. The high/low arrow nock is also the most critical. The reason is that if the shaft is leaving the bow tail low it may affect the arrow's oscillation by contacting the rest as it passes. If the arrow is leaving the bow tail high, the fletching will be fighting air resistance on the shaft as well as the weight of the point to raise it. This will cause your arrows to drop faster than they would otherwise, just as too heavy a point weight would. This is the reason you should be more concerned with high or low nocks, than with left or right nocks. Don't misunderstand me; you should get the left or right nocks straightened out as much as possible. However, if the shafts are slightly left or right of the entry hole at 20 yards after you have exhausted your initial remedies, I still would not recommend you go out and purchase a dozen new arrows.
Can everyone get their arrows to leave their bow straight? Some cannot with the bow setup they now use without some changes. If you hunt with a super fast unforgiving setup with arrows that have too weak a spine for your bow's poundage, or if you shoot a bow with a short brace height, you may find it difficult to get the arrows to come out of your bow straight without making some changes in your equipment. However, I believe most shooters with a few changes, and a little work, can adjust their bows so their arrows will leave the bow straight.
There are four devices or systems that are available which will greatly simplify anyone's attempt to tune so the arrows will exit the bow straight. By the same token these devices will improve arrow flight, which will in turn improve accuracy, speed, and penetration.
The first thing I want to mention is the use of carbon arrows. These arrows are not as critical to the cast of the bow. They will fly straighter from a greater variety of setups than aluminum arrows.
The next thing for release shooters is a caliper release. With two movable jaws, which meet around the string, there will be no string side movements upon release. On the other hand, if you use a rope or single jaw release, the string will torque slightly to the side when released.
The third device that will help you is a nocking or D-loop. This wonderful inexpensive device will, among other things, allows the shooter to release the arrow from directly behind it. When a nocking loop is used there is no twisting the string or preloading the arrow to cause arrow flight problems.
The last item I want to mention is a fall-away arrow rest. It does not help if the arrow starts from the bow straight only to get side tracked by the rest. The fall-away rest is designed to hold the arrow in position for the first few inches of travel and then drop out of the path before the back of the arrow and its fletching reaches it. This type of rest usually uses the forward movement of the cable guard or the downward movement of the bus cable to move it from the path of the arrow. If you have never tried one of these rests, then I believe you will be impressed. They especially show their worth if you, like me, shoot five-inch helical fletching.
After you have your bare shafts flying straight; your fletched arrows will not leave your bow straight if you have fletching contact with the arrow rest, buss cable(s) or riser. Whether you use a fall-away rest or not, insure you test to guarantee fletching clearance. A lot of archers spray white powder on their rest and riser to test for fletching clearance. This is a good method however, I have found that it is better to use lipstick to test for fletch clearance. (If you do not already have some of your own in an emergency tuning kit, you can do as I do and borrow your wife's.) By rubbing some of the red stuff on the outer edge of the fletching and shooting the arrow, you'll be able to see a red mark on anything the fletching touches. If you find that there is fletching contact, you should use arrow nock rotation, and rest adjustment to achieve total fletching clearance; this is crucial especially if you use less forgiving plastic vanes.
Whenever I am discussing bow tuning, someone always asks the question, "how can I set the bow up to be forgiving?" That is exactly what we do when we tune for straight arrow flight. Consider this: Let's assume the shooter's arrows are leaving the bow tail left. Now, let's assume the archer torques the bow in a way that will throw the arrow tail left. With the arrow already leaving the bow in that direction, and the archer adding to the problem, we could now have an arrow so tail left that the fletching might not get the arrow straight before it hits the target. The most forgiving setup will always be the one in which the arrow leaves the bow pointing straight toward the intended direction of travel minimizing the shooter induced error's effect.
When we consider tuning for accuracy, all we can hope to accomplish is that the arrows will leave the bow on a straight path toward the target. In turn, our bows will forgive more of our shooting errors.
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|Date:||Dec 1, 2004|
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