Parts of an Arrow:

Every arrow starts with a long hollow tube (made from aluminum or carbon/graphite) called a shaft. At the end of the shaft will be a small molded plastic piece called a nock. The nock allows the arrow to attach to the bow string. Also on the rear of the shaft will be your fletching. The vanes aid in steering the arrow I flight. On the front of the shaft you will have a small aluminum (sometimes plastic) insert. The function of this piece is to accept either a field tip or broadhead on the end of the shaft.

How to measure an Arrow:

The correct way to measure an arrow according to AMO is by measuring from the groove of the nock to the end of the arrow’s insert. (Do not include the tip when measuring) When you measure to see how long to cut arrows for your bow have a friend help, and draw your bow back with an arrow in it, now have your friend measure 1” in front of the most forward part of the arrow rest that contacts the arrow and make a mark. Anything less then 1” could cause safety issues, especially if you have a string on your bow that stretches considerably.

Arrow Spine:

Arrow spine is the arrow’s degree of stiffness. (How much the arrow resists being bent) When picking out arrows for your bow, this will be something that you will want to pay attention to. You don’t want an arrow that is to stiff for your set up nor do you want one that is two limber. Manufactures will list recommendation for what spine arrow to use with your bows setup. They will also have a number system that will be on their arrows to show what spine arrow it is. Example: Gold Tip-5575, Easton XX75- 2213, Carbon Express-4560 etc.

Most people think that an arrow flies just like it looks sitting on the shelf, but it doesn’t when you release your arrow it will begin to flex and oscillate. If you shoot fingers it will flex and oscillate side to side and if you shoot a release it will flex and oscillate up and down. Since you now know that, if you were to take an underspined arrow and put it in a bow with a hard cam and a heavy draw weight and released that arrow, the chances of that arrow breaking will be great. If that arrow was to break at release then there would be a very good chance that the remaining half of the arrow could be driven into your arm. Another reason for choosing a properly spined arrow other than safety is that it will help you with your accuracy at the range.

There are two types of spine, static spine and dynamic spine.

Static Spine: If you take an arrow and support it at two different points a given distance apart and then hang a weight in the middle of the arrow shaft, the weight will cause the shaft to flex. The arrow shaft’s resistance to being bent is known as its static spine. Arrows do not perform this way though, they perform under dynamic spine.

Dynamic Spine: Dynamic spine is how the arrow will actually flex when released from the bow. Static spine remains the same, dynamic spine will change from bow to bow. If you were take an arrow that had good dynamic spine for a 70# hard cam bow, and then put the same arrow on a 50# bow it would be dramatically to stiff.

Factors that Affect Arrow Spine:

  • Length of Shaft
  • Tip Weight
  • Stiffness of Shaft Material

It is important to know that when an arrow is shot that it bends, not because it is being pulled down in the middle but because it is being compressed. So the longer the shaft the easier the shaft can be compressed, bending it. So if you were to take two identical shafts and cut one 28” and the other 18” the 28” shaft would bend easier than the 18” shaft would. This here is where stiffness of shaft material comes in to play. Say you will need a long shaft for your bow, and your bow will be 70# with hard cams, then you will need a shaft that could remain stiff (not to stiff) while being long.

Remember when the bow is released it compresses the arrow? Ok now on the nock end of the arrow you have the force of the string pushing the arrow one way, but what about the other end? The tip! That’s right, the weight of the tip acts as a force on the front of the arrow pushing it back towards the string causing the arrow to be compressed. The heavier the tip the more force is applied, that is why on a particular bow that shoots a certain spine with an 85 grain tip will need a stiffer spined arrow when you put a 125 grain tip on the end of it.

When trying to decide on what spined arrow to go with you can look at the manufactures website or in their catalog at their charts to see what they recommend, or if you want us to figure it for you, give us a call and we will be more than glad to help out.

Arrow Fletching:

Arrow fletching consists of either 3 or 4 vanes/feathers on the rear of the arrow shaft. The job of the fletching is to help steer the arrow during flight. Note that not all fletching materials are the same. They are available in different shapes, sizes, colors, thicknesses, etc.

There are two popular choices for fletching these days, feathers and vanes. Vanes are made of soft flexible plastic and are a very popular choice for today’s archer. They come in many sizes and colors, they are also quiet in flight and are easy to glue on to the shaft. Vanes are also impervious to water making it an excellent choice for hunting. One downside to the vane is that they weight about 3 times that of a feather.

Feathers are about the best choice for flight (nature knows best) and keeping your arrow stable. Downside to using feathers is they won’t hold up in weather and the basic 4” feather cost about 4 times what a standard 4” vane costs. One other downside is that you can only glue feathers on shafts in a helical configuration.

Fletching Configuration:

There are three ways to mount fletching to the shaft, straight, offset, or helical. Here are the pros and cons of each configuration.

Helical: This configuration provides superior stabilization for broadheads, best arrow flight at long distances, and increased accuracy. A couple of disadvantages are loss of arrow velocity and more problems with fletch clearance. Some rests are designed with limited clearance for vanes so if you have an arrow rest like this you won’t want a helical configuration.

Offset: This configuration provides more stabilization for broadheads than straight; less wind resistance than helical, works with most arrow rests, and provides stable flight to moderate distances. Some disadvantages are that it may cause some fletching clearance problems, and will have a slight loss in arrow velocity. All in all this is probably the most poplar choice of the three here at The Greene Outdoors.

Straight: This configuration provides the fastest arrow velocity, least amount of air resistance, works with any arrow rest due to virtually no clearance problems. There are a few disadvantages to this configuration though less stable at long distances, provides minimal stabilization for broadheads, and if your bow is not tuned you will have poor flight.

If you have chosen to use either the helical or offset configurations, you now have another option. Right or Left? This refers to the direction the fletching will wrap around the arrow shaft. Each works equally well, although most common is the right since when the arrow hits the target it is spinning right which will help keep your tips screwed in tight, if you have your configuration to the left when the arrow hits the target the tips has a tendency to unscrew out of your insert.

We are now ready to discuss fletching size. The most common sizes are 2”, 3” 4” and 5”. The most commonly used size is the 4” vane. The second most factor that determines how much stabilization a vane will provide is the total amount of surface area. Larger vanes will have more surface area than smaller ones. The more surface area a vane has the more air resistance, the more air resistance the more effective the vane will be at correcting the arrow in flight. So you could probably say that 5” vanes have about twice as much surface area than 3” vanes. So it seems the choice is simple go with 5” vanes right? Not so fast, remember in archery you always have trade-offs, if you put a 5” vane on your arrow, granted it will be more stable, but you will have a heavier arrow, and loose velocity and you may have clearance problems with longer vanes especially with short brace height bows.

Here are some examples of vane sizes to use:

Use

Size of Fletching

Tournament Shooting Field Tips/Nibbs2” Vanes
Recreational Target Shooting Field Tips/Nibbs3” Vanes/Feathers
Mechanical Broadheads4” Vanes/Feathers
Fixed Blade Broadheads4” or 5” Vanes/Feathers

Front of Center Balance(FOC):

A projectile’s flight is most stable when the mass is positioned front of center. An example of this would be darts. Darts are heavier in the front than in the rear, now if you were to put the weight on the rear the dart would just spin around in mid air hitting the wall tail first, similar with an arrow. Where would the perfect balance point be on the arrow? Good question and there is not really a right or wrong answer. Usually though anywhere from 7% up to 15% FOC is what you need to aim for, however you will see what works best for you when you go to the range and see what your grouping looks like at different yardages. Now it may seem that the more weight you put on the front the better the arrow would fly, right? Well here is one of those trade-offs again. While the arrow will fly well it will lose trajectory. (Nose-diving) This can be reversed with the opposite, an arrow with little FOC will hold its trajectory much better; however the flight would be very erratic.

Here is how to figure FOC:

Example: Arrow Length is 26”. Divide the 26” by 2. This gives you 13”, your arrow’s center. Balance your arrow and wherever it balances make a mark. Now measure the distance from the center mark (13”) up to the balance mark, and it happens to be 3”. So the FOC is 3/26 which equals 11.5%. Simple enough, right? Again if you have anymore questions regarding FOC please do not hesitate to give us a call, or email.

Speed & Kinetic Energy

We as Americans love speed. Show a guy a brand new bow and most of the time the first question he will ask is, “How fast is it?” Don’t get me wrong there are those archers out there that don’t really consider speed when looking at bows, which is good, cause no matter how fast your bow is if you don’t practice and have good form, you still won’t hit what you are shooting at. Like I have heard before a fast miss is just as impressive as a slow miss.

Arrow Mass Affects Velocity

This is a simple one; the heavier you make an object the slower it will go. Take a 350 grain arrow with a 70# bow and shoot it, now say your speed was 328fps. Now take the same bow and put a 450 grain arrow in it, ok now that bow is only shooting around 295 fps. What a difference. So it seems hey you want the lightest arrow possible right? Not so fast there, remember you have to consider spine, don’t want too limber of an arrow, and too most bow manufactures and even the IBO (if you shoot there tournaments) say you need to shoot at least 5 grains per pound of draw. So for a 70# bow you do 70X5=350, you will need at least an arrow that weighs 350 grains. One of the reasons you do not want to shoot an arrow under this 5 grains per pound rule is that you could risk damaging the bow due to dry fire, and possibly even having the arrow shatter around your arm.

Kinetic Energy

Kinetic energy is moving energy. What determines and arrows knock down power, or how much penetration you arrow will have is how much kinetic energy the arrow has. The more kinetic energy the arrow has the more penetration and vice versa. The heavier the arrow is the more kinetic energy it will have and again the lighter the arrow is the less kinetic energy it will have. But before you get carried off trying to make some heavy arrow you need to consider that the heavier the arrow is the slower it will be. (Trade-offs) So how much kinetic energy do I need to hunt with? Answer is depends on what you are hunting. Easton has a program out that helps you select shafts, and also has a calculator that will show you what your kinetic energy will be and show you what big game animals that figure is good for. One other note, if you go for a super light arrow for the speed you need to know that in some instances if you hit a shoulder plate on a deer, or the shield on a hog that there will be a good chance that your arrow will just shatter, causing you to possibly just wound the animal instead of a clean kill.

I hope that this section has helped you understand more about arrows and there importance. And with this knowledge you will know that there is a difference in just going to pick some arrows up off a shelf and ordering custom arrows. If you have any questions on this subject, or would like to order custom arrows, give us a call, or drop us an email, we will be more than happy to help you out.