If you are looking to start a lively debate in your next archery camp, tell everyone sitting around the campfire that you have found the perfect broadhead and arrow combination and let the games begin. Chances are that a very wide range of opinions will follow, and for good reason. There are hundreds of options when it comes to selecting your projectile of choice and nearly all of them come with tradeoffs. A basic understanding of the major considerations makes it easier to effectively navigate the arrow selection process and will leave you prepared to defend your choice when strong opinions surface in the debate.
I condense my arrow selection criteria into four main categories – flight characteristics, speed and trajectory, energy, and durability. Admittedly, there are a host of additional topics that aficionados can debate for hours on end. However, if you will carefully consider each of the four main criteria discussed here, you can probably let the rest of the archery experts argue about those nuances while you’re busy filling the freezer. In this article, I’ll focus on flight characteristics, and then I’ll discuss the remaining considerations in a follow-up article.
ARROW SPINE AND THE LAUNCH PAD
Sending a beautiful arrow downrange starts with what happens at the launchpad. When you release the bowstring, an incredible amount of energy is transferred from the limbs of the bow into the shaft of your arrow. Naturally, the shaft reacts to this transfer by flexing as it gathers momentum. The amount a shaft will bend under stress is referred to as the arrow’s spine, and it is an important factor in the flight equation. Proper spine plays a much larger role in an arrow launch for finger shooters and for arrow rests that remain in stiff contact with the shaft as it leaves the bow because the arrow’s departure isn’t as clean as it is for someone who is shooting a release aid on a modern compound bow with a fall-away arrow rest. In spite of that, spine will forever and always be a factor in achieving great arrow flight. Since spine charts can easily be found from every arrow manufacturer, I won’t go into more detail here. However, I will step out on a limb and recommend that you are better off shooting an arrow that is over-spined for your bow versus one that is under-spined if you are shooting modern archery equipment. In this context, modern equipment includes a release aid that clips into or around a D-loop, an arrow rest that flexes or falls out of the way, and a bow that has been manufactured in the last 10 years.
HEAVY TIPS AND THE PHYSICS OF FLIGHT
Once the projectile is in the air, the physical attributes of the arrow and the surrounding environmental factors determine how well it will fly. Since every arrow that really matters to a bowhunter is fired outside, I strive to build an arrow that flies great from a physics point of view while keeping in mind that it will probably be pulled out of a soaking wet quiver in a crosswind when the moment of truth arrives.
Few things give me more confidence in my arrow flight than having an arrow that is packing extra weight up front. This is called Front of Center (FOC), and it is a measurement of the percentage of weight that is in front of the midpoint of the projectile. This physicsbased equation has been an important consideration for everything from handmade spears to the modern javelin. It is equally relevant in arrow construction because long projectiles fly better when there is more weight in the front to pull the shaft through the air. To illustrate an extreme example of this, imagine stuffing a baseball in the toe of a long tube sock and then throwing it as far as you can. The heavy part of that projectile will quickly begin to pull the lighter tail of the sock behind it as it travels on its flight path. Rather than explore every reason why this is true, I’ll just say that things always fly better when you follow the rules of physics and your arrows will fly better if they have ample FOC.
Opinions vary far and wide on what the best range of FOC is, but I can usually get a consensus that it should not be less than 10% and there is no top end, provided we are discussing normal methods of adding FOC to your arrow shaft. For hunting North American big game up to Alaska-Yukon moose size, I strive to set up an arrow that approaches 20% FOC. In some ways, it is easy to get plenty of FOC because arrow manufacturers and third party accessory companies provide many options for increasing the weight of the insert your broadhead threads into. Also, you can simply jump up from 100 grain heads to 125 grain heads and add FOC. The downside to adding point weight is that you inevitably add overall weight to the finished arrow, thus diminishing arrow speed, which makes yardage estimation more critical. In light of that, I’ve always struggled to maintain a balance between an arrow that is light enough to travel quickly on a flatter trajectory and one that will fly extremely well from a physics point of view.
I experienced a significant breakthrough on this dilemma two years ago when I stumbled onto the Victory RIP Xtreme Velocity arrows at an archery trade show. I stared at the data on this arrow for a few minutes before I approached a representative from their company and asked, “How are you producing an arrow that is 30% lighter than the industry standard at any given arrow spine?” I was told that it was due to the use of highmodulus carbon in the manufacturing process. I won’t attempt to explain it, but I will say that I immediately placed an order to see if my results matched their claims. Thankfully, my spine and straightness tests did agree with theirs and I’ve been an adamant supporter of this arrow since that first order. By starting with a lighter overall shaft, I can add weight where I want while still maintaining a finished arrow weight that optimizes my speed and trajectory goals. I’m currently shooting a 300 spine shaft with a 60 grain stainless steel insert and a 125 grain QAD Exodus broadhead, which results in an FOC that is right at 20%. Remarkably, the finished weight of this arrow comes in at less than 410 grains, a weight that is heavy enough to accomplish energy goals I’ll discuss in the next article, while maintaining a speed that is more forgiving for those real-world scenarios that inevitably seem to leave me needing a few yards of forgiveness downrange.
WIND, WEATHER, AND OBSTACLES
The primary environmental factor that influences arrow flight is wind. Many archers I talk to tell me that wind drift is not a significant factor in arrow selection because they can’t hold steady in the wind anyway. There is certainly some truth to that statement, but the vast majority of bowhunters will still attempt a shot in relatively windy conditions. As such, we owe it to ourselves and the game we hunt to practice in the wind, be able to estimate what our arrows will do in the wind, and select an arrow with wind drift in mind.
To test wind influence on my arrows, I like to shoot where I can stand out of the wind while aiming but where my arrow will be exposed to the wind for the majority of the distance to the target. The edge of a building, a large tree, or any other similar barrier can provide the necessary shield to aim steadily in really strong winds. This allows me to isolate the wind’s impact on my arrow rather than guesstimate how much the wind blowing my pins off target is to blame. What I have found is that when all things are relatively equal, smaller diameter shafts and lower profile vanes and broadheads (when viewed from the side) will result in less overall wind drift. Again, this makes perfect sense from a physics point of view because the wind simply has less total surface area to push on over the course of the arrow’s flight. To a lesser degree, a smaller profile shaft will also perform better in rain and snow for the same reasons.
Just in case that is not enough of an argument to consider today’s small diameter carbon shafts, the smaller your in-flight profile is, the less likely a fletching or broadhead blade is to make contact with a leaf, branch, or other obstacle that is bent on ruining your hunt and sailing your arrow off course. In spite of that, my hunting arrow of choice is in the median for overall diameter of carbon shafts. There are tradeoffs for nearly every selection you make in arrows and broadheads. For me, I am not a big fan of the components and broadheads that are available for the ultraslim carbon shafts at this time. Given the vast improvements in arrow technology in the past few years, I’m certain I’ll be making another change soon. In the meantime, I couldn’t be happier with where arrow technology has taken us today!
Stay tuned for part two in the August issue where I’ll dive a little deeper into the tradeoffs of arrow selection.