April 27, 2011
BowTech kept the archery world waiting as it prepared to introduce its flagship bow at the 2011 Archery Trade Association (ATA) show.
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BowTech kept the archery world waiting as it prepared to introduce its flagship bow at the 2011 Archery Trade Association (ATA) show. On the show's first day, an enthusiastic crowd witnessed the unveiling of BowTech's Invasion CPX. What they found was a rig that features the company's new Center Pivot Extreme riser design, OverDrive Binary Cam system, pre-loaded, seven-layer HardCore Limbs, FLX-Guard cable containment system, two-piece DymondWood grip and a set of vibration damping accessories.
BowTech's new Center Pivot Extreme (CPX) riser has extended ends that sweep back to meet the limb approximately halfway along its length. This places the pivot point of the limb behind the deepest part of the grip and is, by definition, a deflex geometry riser. Benefits of a deflex riser include inherent stability and accuracy provided by this torque-resistant configuration. The test bow shined brightest in this area, demonstrating amazing stability and a deadly still aim. The center-limb support also reduces overall limb movement, which reduces shock and vibration at the shot.
The Invasion CPX also takes advantage of the longer power stroke offered by reflex geometry designs, resulting in faster arrow speeds. BowTech's FLX-Guard cable containment system uses an arm that bends like a bow limb. When the bow is drawn, it gives way to the tension in the system and bends toward the centerline of the bow, reducing torque. When the shot is fired, the FLX-Guard automatically springs back and out of the way of passing vanes. Two rollers and a fixture capture the cables at the end of the mini limb. An attractive, two-piece DymondWood grip, stainless steel stabilizer insert, Carbon Rod String Stop and durable InVelvet overcoat complete the riser package.
Kick It Into Overdrive
The advertised IBO speed for the Invasion CPX is 343 fps. The power behind the performance is found in BowTech's OverDrive Binary synchronized dual-cam system. An eccentric shaped post called the cam synchronization axle (CSA) extends beyond either side of the cam and is harnessed by two fixtures that are attached to the limb tips rather than passing through the limb material as with typical axle configurations.
This width creates stability and works to reduce cam lean. A series of outside diameter splines on the CSA lock into a set of inside diameter splines machined into the cam. BowTech's CSA is an essential part of the overall system, functioning in a locked dependency on the rotation of the cam. As the cam rotates, the CSA, which has the split end of the cable attached to it, also rotates. Since the CSA is eccentric in shape, it first moves away, pulling the cables tighter while the bow is drawn to peak. It then acts as a letoff mechanism when it rotates back toward the center of the bow.
Tunability of the system is achieved by adjusting the split buss cable. A bow press is needed to change the OverDrive's rotating module to one of the draw length slots from 26-30 inches, including half-inch sizes. Each cam is also home to a draw stop post that is moved into a position corresponding to the selected draw length. System letoff is advertised at 75 percent actual and 80 percent effective.
Editor's Note: Our standardized High Grade testing includes the use of the same equipment and test methods. All bows are tested with a draw length of 29 inches and a draw weight of 65 pounds.
BowTech used a state-of-the-art analysis software program to engineer its seven-layer HardCore Limbs. Each limb is double tapered to work hand-in-hand with the Center Pivot Technology. The double taper reduces dynamic mass and increases the speed of the limb's physical response. A limb that responds quickly is more efficient, transferring more energy into the arrow.
HardCore limbs are also designed with a stiff carbon core, which further reduces mass. In a typical limb, the bulk of the energy is stored near the outside surface, while BowTech's HardCore Limbs, with their super stiff core, put the entire structure to work, storing energy throughout the limb. The top and bottom layers are formed with an impact resistant PET material bonded to a fiberglass stratum. This impact resistance reduces the risk of splintered limbs caused by banging them on hard objects (rocks, tree steps, etc.) in the field. The drastic past parallel position of the limbs, coupled with a set of vibration reducing accessories, kept the kick and noise to a minimum on the test bow.