Field Evaluation: BowTech 'Destroyer' By Jon E. Silks - Senior Field Evaluator
Apr 30, 2010 - 6:38:15 AM
BowTech has been around the industry for about 10 years now and in that short time they went from a small upstart bow company to one of the industry giants. In the early years of my writing I remember having to explain to the readers who BowTech was and what they were all about. Needless to say - I won't waist your time on that now! If you shoot a bow chances are you know very well who and what BowTech is. They have grown and expanded in a remarkable way and have done it through cutting edge technology, acquisitions and customer service. (For more go to: BowTech
For 2010 BowTech has again introduced new technology in the BowTech Destroyer 340 and 350 models. This new rig has a revolutionary new OverDrive Binary cam system, FLX Guard cable containment system, 7-layer HardCore limbs, Carbon Rod String Stop, many finish options and InVelvet Armor Coating.
BowTech Destroyer 340
The BowTech OverDrive Binary cam has enough innovation to be worthy of a new term - Camology: the study of cams. You need to take some time observing this cam to understand how it operates. First, there is a large eccentric post named the cam synchronization axle (CSA), which runs through the cam and through two fixtures that are affixed to the top of each side of the limb. This is in contrast to a typical axle setup in which the axle actually passes through the limb material. The ends of the CSA protrude significantly past the width of the limbs where they capture the buss cable harness. Greater width creates stability and stifles limb twist/cam lean. The CSA is eccentric meaning that the axis on which it rotates is not the same as the geometric center. As the bow is drawn the CSA pulls away and then acts as a let-off mechanism when it rotates back toward the center of the bow. A closer look reveals that the CSA is home to a set of splines that are meshed with a counter set of splines in the cam, essentially creating a "geared" component. Further tying the system together is a tab on the red rotating module near the center of the cam, which matches up with a separate series of splines machined into the cam. A typical cam-on-axle system allows the cam to rotate independently of the axle, however, in Bowtech's OverDrive Binary system the CSA is an integral and locked component that works in tandem with the geared cam. The OverDrive Binary system is not totally locked in place - tunability is found in adjusting the split buss cable harness.
We still have a Binary system in that the buss cable ends are not tied to an immovable object since they are tied to the CSA, which is, in turn, tied to the cam. The OverDrive system generates an 80 percent effective let-off, houses a draw stop on each cam and is equipped with a rotating module that offers draw lengths from 25 to 30 inches in ½ inch increments.
Cam performance can be seen in the relatively smooth draw cycle that the OverDrive system creates, especially when considering the advertised top-end IBO speed of 340 fps.
SO WHAT'S IN IT FOR ME?
A surprisingly smooth draw cycle for a speed bow
A modular draw length adjustment makes for an easy switch.
80% let-off allows you to hold for a longer period of time at the moment of truth
The Destroyer's riser serves as the centerpiece for the entire rig. The riser itself is reflex in geometry and is first forged from 6061-T6 aluminum and then fully CNC machined. A reflex configuration is one that positions the limb pocket pivot points in front of (further away from the shooter) the deepest part of the grip. This increases the power stroke, which is the actual distance that the archer moves the string from its resting position to full draw. All else being equal the result is increased speed. Of course there is always the game of give and take that the manufacturer plays between the speed gained from reflex geometry and the stability afforded by a deflex geometry. Technological advances have allowed the bow makers to narrow the gap somewhat between the two giving their customers good speed with substantial stability.
One of the more unique features found on the Destroyer is the FLX Guard, which is an innovative cable containment system. The Roller fixture is attached to a piece of material that acts much like a bow limb. When the rig is drawn the FLX Guard flexes toward the middle/centerline of the bow to reduce torque and its effects and then at release it springs back into position, out of the way of the arrow. The end of the mini-limb and attached roller fixture are angled toward the centerline of the bow to further reduce friction and in turn, increase efficiency.
Two small screws anchor the Destroyer's one-piece Polymer grip to the riser. The contoured grip is black with two camo inlays on either side. The heel of the grip has the word "Destroyer" embedded along its length.
Other riser features include a stainless steel stabilizer-mounting insert, shelf guard, hydrographic film dipped camo finish and the company's InVelvet coating. This protecting armor coating demonstrates incredible strength and resistance to chemicals such as DEET. It also adds insulating and sound dampening qualities. Realtree Hardwoods HD comes standard on the Destroyer, however, there are many choices including Black Ops, APG HD, Mossy Oak Infinity, Optifade Open Country, Optifade Forest and Next FLX.
The ends of the riser spread out into a U-shape at each end to support the Destroyer's limb pocket system. Both sides of the U-shape are slotted to accept different components of the pocket, which we will discuss in the next section.
SO WHAT'S IN IT FOR ME?
A comfortable grip with a smooth surface for consistent hand positioning.
The FLX Guard is unique and functional, pulling its weight in the fight for efficiency
The many camo choices should suit just about anyone
Bowtech's InVelvet coating is comfortable, providing a measure of insulation no matter where you are gripping the bow as you travel to your destination.
The carbon rod string stop deadens string vibration and keeps the string from your forearm and clothing.
Performance in Layers:
Destroyer limbs continue BowTech's march toward new technology with their layered construction. Approximately 4" of the limb on the end that harnesses the cam contains seven individual layers. The two layers on each side of the limb are Biaxially Oriented PET impact Resistant Film. The next in line from the top is a S-Glass Tension layer followed by a 6061-T6 aluminum stiffener. Aluminum provides strength and rigidity to the limb tip. In the middle is a High Modulus Carbon Core from which the limbs get their "HardCore" name. A material is said to have a high modulus or high modulus of elasticity when it is resistant to deformation - in other words, it is really stiff! The Destroyer's carbon core limb material has 2x the stiffness of fiberglass and is lighter. BowTech's design is intended to bring the core into play for energy storage where typical limbs do most of the work on the outside edges. The more of the limb that shares the load the more evenly distributed the stresses will be and in turn the more durable the limb will be. Under the core are two E-Glass Compression layers, one of which is red in color. The laminated and machined limbs measure 13" in length and are matched based on deflection values for consistent limb sets.
One of the more important aspects of the Destroyer limbs has to do with their position at full draw. BowTech calls this (or at least they used to) their Vertical Force Technology (VFT), which is the name given to define the equal and opposite distribution of force in the limbs upon release. Much of the energy leftover after propelling the arrow is cancelled out and the result is a bow that displays significantly reduced shock and vibration.
Destroyer limb pockets are fully machined one-piece 6061-T6 fixtures that control the limb both horizontally and vertically. They are minimal in material and lightweight. The limb bolt end of the pocket has a tab that fits down into a slot in the riser. On each side there are screws that lock the pocket in place further solidifying this important interface. The pocket inserts are made of German engineered bearing material known for its minimal friction and high strength. Pockets pivot during the draw weight adjustment process. A pivoting pocket, rather than a pivoting limb more precisely controls the movement and tolerances at this critical riser-to-limb interface.
SO WHAT'S IN IT FOR ME?
Parallel limbs = less shock and vibration at the shot.
Pivoting limb pockets are more precise and consistent
The layered technology in these limbs are designed for performance and durability
As they say, "The Proof is in the Pudding" and in the case of the Destroyer all you have to do is shoot it to know this bow is a winner.
Since my last Bowhunting.Net bow report I have started to standardize my testing across many of my writing "outlets" (magazines, websites, etc). To bring Bowhunting.Net into line with that effort testing will be as follows:
All test bows will be initially set up with a single brass nock and a QuikTune 3000 arrow rest. If there are any accessories or string loops on test bows I receive they will be removed for testing. All other aspects of the bow will remain in the "As shipped" condition meaning that any factory standard string silencers, riser vibration dampers, etc will not be touched.
Each bow will be tested at a 30" draw length, 70-pound draw weight, shooting a properly spined 350 grain arrow, which has become the industry standard for rating a bow's speed. This rating is also known as the IBO rating. I.B.O. (International Bowhunting Organization) publishes a set of rules that regulate the parameters of a bow setup which archers are permitted to use while participating in one of their sanctioned events. The IBO rating method, however, is not a standard and assumes some variability. With that in mind I have coupled the commonly accepted IBO ratings with the testing methods of ASTM, which defines how you measure a bow's draw length, speed, etc and also defines the minimum and maximum deviations allowed in measurements. What this all comes down to is a hybrid test method which combines the accountability of a defined standard with the modern industry accepted rating method.
With that said, we will set the test bow's draw length to 30" and draw weight to 70 pounds as defined by ASTM standards. We will then use a 350-grain arrow to rate the bow's speed. Test methods will also be taken from ASTM, as we will use the proper tools set at specified parameters. This involves a shooting machine, mechanical release, and a chronograph meeting specs. A minimum of 5 shots will be averaged to come up with the final velocity. A force draw curve will be plotted for each test bow and the following testing results will be reported:
Kinetic energy will be calculated using the following formula: Tested speed x tested speed = result (1). Result (1) x 350 = result (2). Result (2) / 450,240 = final result expressed in foot-pounds.
Stored energy will be calculated using the following formula: Add up all the readings under the draw force curve = result (1). Result (1) /the number of points used to calculate result (1) = result (2). Result (2) x power stroke in feet = final result expressed in foot-pounds.
Efficiency will be calculated using the following formula: Kinetic energy/stored energy = final result expressed in %.
I will also provide my personal comments about each test bow in the "This is how I see it" section of Bowhunting.Net bow reports.
Test results (350-grain arrow):
Tested Speed - 338 fps
Kinetic energy - 88.8 ft lbs
Stored energy - 105.64 ft lbs
Efficiency - 84.1%
This is how I see it:
I have written a few reviews on the BowTech Destroyer series so far this year and if you have had a chance to read any of them you already know that I consider this to be one of the finest bows ever produced. The shootability combined with raw performance sets the Destroyer apart.
When the testing started I performed a general overall quality inspection of the fit, finish and mechanical function. This is basically a measurement of the workmanship that goes into the bow. I found no issues with any of these.
BowTech Advertises an IBO range of 332-340 fps for the Destroyer 340. As you can see from the test results they hit that range, which is exactly what we should expect as consumers. In fact, the Destroyer 340 almost hit the top of their advertised range, which is even better. Unfortunately not all manufacturers follow suit.
The 340 and 350 models both have excellent shooting characteristics with minimal noise, shock or vibration at the shot. The 350 was the first Destroyer I shot and was impressed with the shooting experience - this was last fall before I had looked at any of the specs or even realized there were two models. While talking to a guy at BowTech I asked him what the IBO on the Destroyer was. He said its right on the limbs, it's the Destroyer 350! That really surprised me considering the lack of shock, vibration and noise. The 340 model has equally impressive performance with an inch longer brace height for a slightly more forgiving shot.
Can the Destroyer series be improved? Of course, every bow can be and I have no doubt that is exactly what BowTech will do in the coming years. I expect one area that we may see a change in next year will be in the grip. Don't get me wrong, the grip is comfortable and functional and serves its purpose. I personally prefer wood, however, and would opt for laminated side plates in place of the one-piece polymer. That is just a personal preference so you may well prefer the polymer.
Another plus on these rigs is their draw cycle. Although it is somewhat aggressive BowTech has smoothed out the transitions in just the right places making the draw feel much easier than you might expect on a speed bow.
Spec Sheet :
Model: Destroyer 340
Eccentric System: OverDrive Binary
Draw lengths: 26 - 31 inches in ½ inch increments, rotating module
Letoff: 80 percent effective
String: BCY 452X, 61.56 inches
Cables: BCY 452X, 35.63 inches
Riser: Reflex, fully machined aluminum forging
Grip: One-piece molded polymer
Cable Guard: FLX Guard
Limbs: HardCore Laminated
Draw weights: 50, 60, and 70# peak
Brace Height: 7 inches
Axle-to-axle length: 32.375 inches
Mass Weight: 3.9 pounds
Advertised IBO speed: 332-340 fps
Finish: Realtree Hardwoods HD standard plus many other options
The Destroyer 340 is exceptionally accurate, shock-free and easy
to draw. And it's fast — very fast. This incredible balance is
accomplished using three new technologies: HardCore Limbs™, OverDrive
Binary™ and FLX-Guard™. While most archers are forced to trade
shootability for speed, the Destroyer legitimately delivers both and
retains the "dead in the hand" shooting characteristic that BowTech is