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A STICK, A STRING, AND A HORSE

When some folks get their first look at a BLADERUNNER bow, their first comment is “It looks too complex” or “Looks like too many parts”. Yes, there are more parts on a BLADERUNNER than there are on a conventional compound bow. But the “extra” components that are present are not there just to make the BLADERUNNER “look” different from other bows. Each component on the BLADERUNNER is specifically designed to act as an integral part of a unique overall geometry that provides the superior performance, accuracy, and versatility that you will experience when you own and shoot a BLADERUNNER bow.

Having been involved with archery and bowhunting since a time when only traditional bows were available, I can’t help but think back to when the first compound bows were introduced. I remember distinctly reading the articles and reviews from the archery “experts” of the time and I remember hearing the comments from many of my “expert” bowhunting pals. Predominantly, their comments and opinions went something like: “Man, that thing is too complex”, or “Look at all of those pulleys, brackets and cables, way too many parts”, or “Nobody is really going to hunt with one of those contraptions”.
Of course, we know now that all of those “extra” parts and perceived “complexity” was precisely what made the compound bow deliver the exceptionally superior performance over the traditional stick and string. But back then many of the “experts” were just too short sighted to look beyond all of those ‘extra parts” and see the true potential of a superior design concept. Unfortunately, in many cases, the same lack of vision seems to persist today with the only difference being that, instead of traditionalists implying that anything more complex than a stick and a string can’t be any good, now it’s conventionalists implying that anything that appears to be more complex than a conventional compound bow just can’t be of any benefit. Of course, if we all subscribed to this type of logic, we would all still be driving a Model T instead of a high performance truck or S.U.V., or maybe we would all still be riding a horse. Whatever you believe, however, you must admit that advances in technology and performance often demand a few “extra parts”.

So, let’s examine what the BLADERUNNER has that conventional compound bows don’t, and why.

One of the first things that you may notice is that the BLADERUNNER has two additional spools located between the pylons and just below the pylon-mounted cams. We will get to why the BLADERUNNER mounts the cams on pylons later, but right now I’ll explain the extra spools. These spools are called “intermediate spools” because they provide several beneficial functions that occur between the cams and the action of drawing the bowstring. One of these functions may be obvious to some because of the short axle-to-axle length of the bow. The BLADERUNNER was designed to be an ultra-compact, highly maneuverable hunting bow. But, with an axle-to-axle length of about 26 inches, it would be virtually impossible to obtain a draw length much beyond 27 or 28 inches using conventional design. The intermediate spools serve to store an additional length of bowstring at brace that allows for a range of draw lengths that even exceed what is obtainable on longer, conventional compound bows.

Something interesting to note with respect to conventional compound bows relates to the use of parallel limb design (which, by the way, was first introduced almost twenty years ago on early prototypes of the BLADERUNNER bow which was then called simply “the SHORTBOW’).
Prior to parallel limb design, the direction of limb travel was back toward the archer when the bowstring was drawn. This direction of limb travel contributed somewhat to the overall draw length required allowing the profile of the cams at the limb tips to be relatively small. In other words, the amount of bowstring stored on the lobes of the cams combined with the travel of the limbs allowed for a reasonable range of draw lengths. Of course, the resulting forward motion of the limbs and cams when the bowstring was released created a high amount of hand shock, vibration and noise when the bowstring returned to the braced position. Parallel limb design virtually eliminated much of the shock and vibration due to the fact that the limb motion was converted from forward travel to an up and down travel where the motion of one limb opposed the motion of the opposite limb with somewhat of a shock-canceling effect. However, when parallel limb design was introduced to conventional compound bows, it meant that the previous rearward motion of the limbs was no longer present and could not contribute sufficiently to draw length requirements. In order to compensate for that portion of the draw length that was previously afforded by the travel of the limbs, the amount of bowstring stored on the cams (or cam) needed to be increased resulting in the substantially larger cams seen on conventional compound bows with parallel limbs today.
There are several disadvantages associated to these larger cam profiles however. One disadvantage is that the increased mass at the limb tip increases inertia and therefore decreases efficiency. More important, however, is the fact that a larger profile places the exit point of the bowstring from the cam (or idler) substantially farther from the axle. This results in magnifying the detrimental effects of limb twist and cam or wheel lean that is unavoidable with conventional compound bow design.

So, the intermediate spools on the BLADERUNNER makes obtaining the longest draw lengths possible, even with an ultra-compact, parallel limb configuration. And because the BLADERUNNER’S unique design completely eliminates limb twist and wheel lean, the ill effects of those conditions are eliminated as well.

But draw length is not the only issue that the use of intermediate spools addresses. Yet another factor, particularly important when parallel limb design is utilized, is that of the relationship of the speed of travel of the bowstring to the reaction time of the limbs.

In other words, one must consider how fast the bowstring is being drawn back into its stored position in relation to how fast the limbs (which are driving the rotating components) are returning to brace. The relationship of the lever arm ratio of the lobe of the cam that carries the bowstring to that of the lobe of the cam that is operational with the cable is calculated and designed to create a force/draw curve that regulates the amount of stored energy in the bow. However, the same sequence of cam ratio change that is necessary to produce the desired force/draw characteristics also results in a sequential reduction in the recovery rate of the bowstring onto the cam and does not allow the travel rate of the bowstring to be maximized in relation to the travel rate of the limbs. On bows that do not use a parallel limb configuration, the forward motion of the limbs contributes to the forward travel rate of the bowstring and, to a degree, offsets the effect of the cam ratio. However, on a conventional parallel limb bow, relatively little of the limb travel can contribute to the forward speed of travel of the bowstring so the compensation that is necessary to offset the cam ratio effect comes only from the increased size of the cam, and as previously mentioned, a larger cam profile comes with some undesirable consequences.

The intermediate spools provided on the BLADERUNNER bow act to provide an intermediate ratio that increases the speed at which the bowstring is being retracted in relation to the reaction time of the limbs. This effectively offsets the cam ratio effect allowing for relatively small cam profiles to be utilized on a short, parallel limb bow, and without any loss of efficiency, accuracy and without any other ill effects.

The use of intermediate spools in conjunction with pylon-mounted cams (here’s where we get to the part about pylon-mounted cams) allows components to be oriented in a manner that places both the bowstring and the buss cables precisely centered on the limb tips. This means that loading on the limbs is always balanced and that no limb-twist or wheel lean ever occurs. Can’t do that with conventional, limb-mounted cam design. Also, using pylon-mounted cam/spool assemblies allows the upper cam to produce deflection in the adjacent upper limb and the lower cam to produce deflection in the adjacent lower limb. This eliminates the spanning of buss cables from the upper to the lower portion of the bow that must be offset by means of a cable guard rod. Isolating the individual limb and cable loads at the respective ends of the bow means that those loads are not transmitted through the riser and therefore riser torque is eliminated.
The pylon-mounted cam/spool system design also facilitates the totally symmetrical, true center-shot, balanced geometry that allows the BLADERUNNER to produce superior arrow ballistics and unmatched terminal performance.

Finally, the pylons also contribute to a proprietary means of locating a limb bolt anchor in a manner that allows for the removal of all limb loads and cable and string tension so that a bow press is not required to change a bowstring or cable, install a peep-sight, or perform any other required maintenance or task.

Naturally, with the cams and intermediate spools located on riser-mounted pylons, idler wheels are located at the limb tips to carry the bowstring at that location. So, instead of just two cams, or just one cam and one idler wheel, the BLADERUNNER uses a cam, an intermediate spool, and an idler wheel at each end of the bow.

Just as it was necessary to add cams, brackets, cables, and other components and to make certain other modifications in order to create something superior to the traditional stick and string, it was likewise necessary to add some additional components and create an improved geometry in order to produce a superior compound bow, the BLADERUNNER.

Now don’t get me wrong, if the presence of a few more components that provide an advanced technology, superior accuracy, and improved performance in a compound bow frightens or confounds you, that’s okay. But I hope that you will give the BLADERUNNER a closer look. I think that you might just discover the true simplicity of advanced design and I am sure that you will find that the BLADERUNNER is a pleasure to shoot.

Of course, if you just can’t bring yourself the warm up to the ultimate in advanced bow design, but you are a bowhunter, then I am on your side as well. Just grab your stick and string, jump on your horse, and let’s go bowhunting.

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