Introduction of AeroBolt
Since 2011, Firenock has built AeroBolt by using common off the shelf components to address the issue of the weak front end of high speed crossbow bolts. With the advances in knowledge via intensive research, Firenock LLC now offers 2 AeroBolt II to satisfy most discrete crossbow shooters; AeroBolt II-200 (AB20) and AeroBolt II Dragon Slayer (ABDS). Each model of AeroBolt has specific characteristics to fit the different needs of archers.
AeroBolt II comes standard with AeroPoint and AeroInsert. Both have our US patented self concentric technology / FACT Technology (Firenock Arrow Concentric Technology) built in them. The beauty of AeroPoint is whenever AeroPoint is inserted into an insert, AeroPoint will automatically < 0.002" concentric itself even without tuning. AeroPoint is also the only arrow point that eliminates the issue of loosening after repeated shooting. This is the reason why AeroPoint is a standard component for AeroBolt II as AeroPoint is the best point available on the market.
The AeroBolt™ II-200 (AB20) crossbow bolt is new for 2013. AB20 is offered in lengths from 20" to 26" and is engineered and designed for maximum flight stability and maximum speed just like AB25, but with a stiffer primary shaft that has a spine of 0.200" and inner of 0.350". The weight of the 26" AB20 without AeroPoint, AeroInsert, and inner carbon extension (i.e. hybrid insert), is 300 grains and 325 grains with the hybrid carbon insert excluding nock and point. It has an amazing 0.001" straightness shaft. Beginning on January 1st, 2013 all AeroBolt II are spine indexed and marked. Just like AB25, the hybrid insert cannot be removed, as it is built as part of the arrow shaft in the manufacturing process. This crossbow bolt also has a variable spine design, which means the spine in the front is different than that of the back. The front is about 0.060" and the back is 0.200".
The AeroBolt™ II-G (AB2G) crossbow bolt is the big game hitter of the AeroBolt II family and is new for 2015. It is designed to be the companion delivery system for our latest Traumahawk broadhead. The AeroBolt II-G is designed with exactly the opposite approach of AeroBolt II-200, 300 and 350. Aerobolt II G is designed to get minimum front of center in order to get the flattest trajectory bolt flight. This design moves the center of gravity of the arrow away from the front, so the crossbow arrow can fly as flat as possible. AeroBolt II-G is designed to reach a much longer distance, but with enough power to penetrate deep or pass through the largest game animal. To accomplish this requirement, we have to overcome the main obstacle, momentum. Therefore, Ultra High Front of Center (UHFOC) is the main design criteria of AeroBolt II G.
From our test of UHFOC crossbow arrows with Aerovane III, Aerobolt II-G is found to refuse to drop even at great distance. The speed of the arrow indeed dropped when it reached the first 30 yards, but it dropped less as distance increased. The dial gauge gap between 40 and 80 yard mark shrank significantly. The magic of AeroBolt II-G is that its double shoulder insert and light weight high modular carbon insert forced the oscillation cycle of the arrow to shorten significantly. Also the bolt very soon behaved like a Gyro due to the effect of Aerovane III and the large frontal focus mass. Although the bolt slowly decelerated as distance increased, most of the energy could still be retained due to Gyro effect. In short, AeroBolt II-G does not perform like a general archery projectile, but it is a Gyro enhanced projectile. These explained why Aerobolt II-G has significantly more wind defying and gravity defying characteristics than a typical Aerobolt II crossbow arrow.
In order to make new AeroBolt II-G works, the following criteria are needed:
1) The arrow must spin over 2500 rpm
2) The frontal focus mass should be more than 200 grains (225 is found to be ideal)
3) The arrow has minimum oscillation at launch
4) Minimum drag / close to Zero drag for this arrow to work
5) Length of arrow should be euqla or longer than the power stroke
6) The straightness of the arrow is recommended to be 0.006" or better
7) Concentricity of every components are extremely critical due to the nature of high speed spin
8) Vane position, vane weight, and glue weight are very critical due to the nature of high speed spin
9) Indexing the Initial First Bend is critical in order to achieve same repeatable launch arrow after arrow
To achieve the above criteria, the following parts are custom made or utilized from our arsenal:
1) 100 grains Stainless Double Shouldered and Reverse Tapered Insert (US Patent 8,403,777 & 8,337,342)
2) Ultra high modular, light weight inner shaft (40+ million modular carbon)
3) Broadhead with its weight at the outer parameter and at least 175 grains, Traumahawk (Patent Pending)
4) Aerovane III (US Patent 8,105,189)
5) A durable high modular carbon outer shaft (33 million modular carbon)
6) A 10mm wide, 9mm base at 175 grains AeroPoint™ (US Patent 8,337,341) is included.
AeroBolt™ II Dragon Slayer (ABDS) crossbow bolt is the big brother of the AeroBolt II and is also new for 2013. ABDS is our top of the line crossbow bolt. It is offered from 16" to as long as 26". ABDS is engineered and designed for maximum momentum and penetration. Unlike any other crossbow bolts, it has a 0.092" thickness of carbon throughout its entire length. Instead of one inner and partial shaft configuration, it has 2 inner shafts that run most of the length of the bolt. The inner 2 shafts are engineered to be super heavy and super stout. In addition, ABDS comes standard with Firenock AeroInsert-DS and Firenock’s newly designed 0.244" extreme shock end cap to fit the Firenock F, D, J, M, Q and V, lighted nocks. With this design, every single component on the bolt is supported by no less than 2 shafts, and in some cases all 3 shafts. With a 26" shaft, the expected total weight (excluding point and nock) is going to be about 750 grains with 3 Aerovane II. This configuration makes this arrow the ultimate African big game crossbow shaft, as many African range game laws have stated you must use no less than a 1000 grain archery projectile for taking the African big 5. From our field staff reports, it is also found that it is the best shaft for the huge wild boars that roam the lower states, like the 700lbs+ hogs found in Georgia and Texas.
AeroBolts are fletched with Aerovane™ II or Aerovane™ III vanes. (3 vanes on each AeroBolt is the standard configuration). The standard color combination of Firenock AeroBolt II (3 vanes) is white, yellow and red. 2 vanes, 4 vanes, and custom vane color configurations are also available. One can also order a specific color combination of vanes for the arrows upon request or even purchase the AeroBolt II without any vanes fletched. Aerovanes on AeroBolts are fletched with the ultra high precision Aerovane Jig and super strong Aerovane Glue AG0600. One can also choose the material for the AeroInsert: DA for Aluminum (17 grain) and DS for Stainless (50 grain) (US Pat). Furthermore, one can order AB20 and ABDS in custom weights and lengths.
The weight and length of standard configurations of AeroBolt no nock, point and vane are:
If you wonder how loud and what it looks like when one shoots AeroBolt II, here is a video provided by a new customer shooting his AeroBolt II 100 yards under 15 miles breeze and he has shot AeroBolt II for only 3 days.
AeroBolt II-200 24" out of Scorpyd Ventilator 150 at 366 fps with 15-25 mph cross wind at 100 yards with Hartcraft Trophy 1 broadhead
AeroBolt II-200 24" out of Scorpyd Ventilator 150 at 366 fps with 15-25 mph cross wind at 100 yards with Smoke Ramcat 100 broadhead
WHY AeroBolt II IS PRICED AND BUILT IN THIS WAY?
Most people will find that most crossbow arrows are performing quite well. But why AeroBolt II is better than the other arrows? Why the price of AeroBolt II is significantly higher? Why Firenock built AeroBolt II like this? What are the reasons behind these questions? One will understand and be convinced why after reading the below: a short review of research and development of AeroBolts and its design and technologies. Furthermore, with better understanding of AeroBolt II technologies, one should acquaint what one can expect and what one can achieve the most from shooting with AeroBolts.
Back in 2009 when Jim Kempf of Scorpyd requested for a heavier spine crossbow bolt due to the introduction of the RDT165, the concept of AeroBolt was born and built. AeroBolt I was based on Gold Tip Laser II, Laser III, other Gold Tip shafts, and Gold Tip Series 22 insert. At that time, AeroBolts were nothing more than a piece of Gold Tip shaft ( 0.298” OD) Laser II or Laser III glued with a Gold Tip Series 22 insert. This process gave Jim the arrow he needed at that time as this configuration gave the crossbow arrow a much heavier resulting spine and it lessened the issue of not locating the spine due to dual shaft construction. During the testing of this arrow, interesting facts were discovered and these leaded us to develop new concepts, break through manufacturing processes, improved design, which these resulted in at least 4 US Patents which are being utilized in the current series of AeroBolt II crossbow arrows.
Development of never harden 2 part epoxy
When the first AeroBolt was made, the use of CA base glue was the original ideal as a tiny amount of glue was needed to secure the system. But after a few shots, like many had tried, the CA base glue just cracked and caused layer separation of the carbon. This was even worst after the arrow was shot repeatedly and particularly for arrows with lower spine. After dissecting the shaft, it was found that the CA glue was indeed cracked leading to layer separation and the CA glue became powder and made the situation even worst as the arrow flexed more due to the cracks.
A variety of glues were tested ranging from Super Glue, CA GEL, 5 minutes, 10 minutes, and even 30 minutes epoxy, but they all failed. Through the tests, we did discover that the longer the glue time, the better the result could be achieved. These results coincided with the theory that glue failure was due to fracture via the flex of an arrow during launch which leaded to carbon layer separation, then resulted in inconsistent of spine and finally ended up with inconsistent arrow flight.
After discussing with our glue supplier; a rarely used, super expensive 2-part epoxy was suggested and was tried. This epoxy is ideal as it will be flexible even it is totally cured. Furthermore it allows us to have close to 2 hours of work time, but this epoxy has high cP (i.e. does not flow and spread well). To assemble an inner shaft as long as 13”, the usual apply and spread method would not work, thus a special gluing process was developed. This special gluing process allows us to apply the glue perfectly and evenly between the 2 shafts even at long spread distance.
Development of ultra sound cleaning process
After extensive testing, Firenock found that high quality flexible glue is the only way to assemble a multi component arrow, however, high quality glue only works when all components are perfectly clean (no dirt, carbon powder, oil, etc). To solve this problem, Firenock custom made a tall and narrow dual transducer ultra sound cleaner and uses Acetone as a solvent at room temperature to clean the arrow tube before gluing and assembling.
Development of AeroInsert-D
The inherent issue of using a Gold Tip series 22 insert was observed while we have started to build the AeroBolt. Gold Tip insert is short and does not have a lot of gluing surface. The result of small gluing surface caused cracks of arrow shaft right behind the insert when the arrow was shot at an extreme angle. With the understanding of this issue, Firenock made AeroInsert-D to solve these issues. AeroInsert is not just a metal insert, it is a hybrid insert which it is a metal insert inserted into a carbon tube which this hybrid insert is inserted into the crossbow arrow shaft. Below are the features of Firenock AeroInsert-D:
1) Large gluing surface: As AeroInsert-D is long, it can provide larger gluing surface than conventional insert. As the gluing surface is larger, force can distribute more evenly and thus less stress will be asserted to the carbon shaft.
2) Small run out. As AeroInsert-D has a long carbon shaft, its run out is virtually zero. It is simple to understand as when longer surfaces are slided over each other, the less run out it would be. In case of the Tac 15’s 26” long arrow, the carbon shaft of AeroInsert-D can be as long as 13.5”.
Development of FACT (Firenock Arrow Concentric Technology)
From long discussion with archery arrow experts like Randy White, Tim Gillingham, one issue becomes obvious, it is the degree of concentricity. In other words, it is concentricity of arrow, concentricity of bow and concentricity between arrow and bow. On the present market, according to Firenock research, there is not a crossbow arrow or arrow rest that can provide enough concentricity to ensure accuracy of an arrow. With the AeroInsert D, Firenock believed that the insert to shaft concentricity has been addressed, but the concentricity of the field point/broad head has not been addressed. For vertical bow, it is confirmed that broadhead tuning and using glue in point can improve concentricity / accuracy as the highest focused mass is concentric to the entire archery projectile. It is obvious that the field point and/or broadhead needs to be concentric to the entire archery projectile in order to improve accuracy. This importance of concentricity leads Firenock to develop a US patent for AeroPoint, which is known in the industry as FACT (Firenock Arrow Concentric Technology). Anyone in the pipe fitting business will tell you; when 2 pipes need to be inserted and removed from each other, the use of 2 partially embedded O-rings is ideal. This double O-rings design is what an AeroPoint or AeroPoint licensed broadhead has employed. When AeroPoint with double O-rings is installed into the insert, it is automatically perfectly concentric and tightly fitted into the insert. After a few shot, the self-tightening effect of double O-rings will kick in and lock the field point or broadhead into the insert even more tightly.
Development of Self Harmonic Dampening AeroBolt
One may not know what is Harmonic Dampening, but this is the sole reason why AeroBolt is so superior in performance and so deadly accurate. Harmonic Dampening is observed when the first AeroBolt was shot:; the oscillation of the AeroBolt stopped only after about 5-10 feet was observed. This observation has been discussed with many archery experts but no one can provide us a definite answer. The answer was found out until material science experts were consulted.
What the material expert had explained was that when an arrow was shot out of a bow, a general arrow would usually oscillate for its initial 20 yards of flight based on the physical characteristics of the arrow. The lighter the spine and the longer the arrow, the more the arrow will oscillate and will take longer time to stop oscillating till the arrow goes into a full gyro spin (i.e. no oscillation). From our tests, it was also discovered that the heavier the material used to build the arrow, the arrow will oscillate more and the arrow will lose more energy in terms of KE as more mass is being moved.
Development of 2 different carbon tubings to form the arrow
AeroBolt uses 2 different carbon tubings to form the arrow. This is due to Firenock discovered that the more different the 2 carbon tubes are, the better the arrow will fly and the longer the carbon tube, the higher the resulting spine of the arrow will be and thus arrow will oscillate less. The result of gluing 2 different tubings together makes the magic; the oscillation cycle of the dominant shaft is shortened by the inner shaft.
Spine Indexing and Matching as standard specification
Firenock AeroBolt was designed base on the concept of multiple shafts construction; the effect of spine cancellation will minimize the effect of the dominant arrow shaft’s spine effect. As spine effect seems to be eliminated due to 2 shaft construction, Spine indexing seems to be not important. But Firenock still has offered shaft indexing since 2011 as part of our standard to AeroBolt manufacturing process. Firenock feels that AeroBolt is the ultimate crossbow bolt and spine indexing has proven to be important, it should be part of the standard.
Development of Professional Arrow Preparation System
To locate the spine of an arrow, most use the RAM Spine finder machine. The unfortunate fact is that it takes too long to spine an arrow and it is not reliable. Most shaft spine-indexing machine is not meant for production use, thus Firenock believed that a more specific machine should be built. So we did. By the beginning of 2014, we will be offering the PAPS (Professional Arrow Preparation System). PAPS will be a easy to use tool with future add-on accessory ability. One of the add-on accessories is our vibration generation module. Unlike other tool / machine, our vibration generation module is designed to find the softest side of natural spine of an arrow easily within 5 seconds.
We believe locating the softest side of natural spine is more important than the hardest side as an arrow will flex towards it softest side when it was launched. In other words, an arrow will flex towards the lowest resistance side. The hardest side only shows the hardest spine rating which IMHO is not critical for arrow accuracy, but the average spine is what an arrow will flex and dictate the arrow in flight oscillation, thus the initial launch is always base on the softest side of an arrow.
Use of Aerovane to Lift instead of using Drag
AeroBolt uses Aerovane as its standard vanes. Typical arrow vanes use drag to cause the arrow to spin, this will make a lot of archers preferring to use a much heavier field point and/or broadhead as heavier field point can compensate the drag factor from the typical vanes so the arrow will have 2 opposite forces; with the front heavier point being the dominant force to drag down the arrow and with the vanes at the back to stabilize the arrow from the dip and to force the air passing the vanes causing spin. This also explains why some arrows need heavy FOC (Front of Center) in order to fly right.
For Aerovane, Aerovane is using lift to spin the arrow, not using drag to spin the arrow. The working principle of Aerovane is just like an airplane wing; air moves at different speed above and below the vane surface due to the unique shape of Aerovane and thus creates lift. The use of lift explains why an arrow equipped with Aerovane does not need heavy FOC in order to fly true. By not needing a heavy FOC, the hang time of an archery projectile will be significantly increased. Case in point, an identical archery projectile in weight when fletched with Aerovane II leaving the bow at 380 fps will have the same flight characteristics of an arrow fletched with typical vanes at 2.5 degree offset shooting at 420 fps.
Development of Gluing instead of mechanical fastening
As the front end of the arrow will encounter extreme amount of force and vibration in all unpredictable direction upon impact, mechanical insert will actually focus the force and vibration upon impact and can make damages to the shaft inner surface. In many cases, catastrophic failure of arrow using mechanical insert are often seen. For safety and reliability, spreading force over a large surface is the best way to resolve this problem, thus Firenock developed hybrid insert system, which our hybrid insert is long, made of carbon and the hybrid insert system is glued into the arrow to make a perfect fit in order to spread the force and vibration upon impact.
Spin Index and Spine Index in the Future
All AeroBolt IIs are spin indexed and spine indexed with our US patented PAPS with vibration generation module. The spine index is marked with the stiff side up with a permanent marker.
From the above, one should understand that AeroBolt with hybrid insert system will oscillate less than other arrows. With Aerovane, AeroBolt can use less FOC as it is using lift instead of drag to spin arrow. The combination of hybrid insert system and Aerovane make AeroBolt to oscillate less, stabilize itself faster and achieve gyro spin faster during its flight. Achieving gyro spin means less energy will be lost and now all the energy is stored in the arrow to make a flatter flight and thus the arrow can become more accurate.