Firenock:AeroBolts


Introduction of AeroBolt
    The initial objective of making Aerobolt was to address the issue of the weak front commonly found in high speed crossbow bolts.  In 2010, we built Aerobolt I using common off the shelf components and it performed quite well, but Firenock found that common off the shelf components had concentricity issue and also had fundamental design issue, thus Aerobolt I was good but not at its full capacity.  With more data after testing and with the introduction of Firenock AeroConcept System, Aerobolt II was built which we overcame not only concentricity issue , but we made the front end stronger than ever and we believed that Aerobolt II is the best bolt available for today's archers.  Three models of AeroBolt II are built; they are AeroBolt II-200 (AB2-200), AeroBolt II Dragon Slayer (AB2-DS), and Aerobolt II-G (AB2-G).
    All AeroBolt™ II is loaded with Firenock US patented Self Concentric Technology / FACT Technology (Firenock Arrow Concentric Technology) and Hybrid Insert System.  The beauty of Self Concentric Technology is that AeroPoint and AeroInsert will self concentric to the shaft once assembled even without tuning.  Meanwhile, AeroPoint is equipped with our patented Double O-Ring System to eliminate the issue of loosening even repeatedly shot.  Hybrid Insert System (i.e. Firenock Patented Double Shoulder Insert with Carbon Inner Tube) which not only strengthened the arrow front end but gave Aerobolt II a variable spine characteristic which this unique characteristic shortened the oscillation cycle of arrow (i.e. Aerobolt can fly straight and conserve energy).  These Technologies allowed Aerobolt II to fly straight and hit accurately and AeroPoint would not come off even after repeatedly shot.

The AeroBolt™ II-200 (AB2-200)
AB2-200 crossbow arrow is engineered and designed for general purpose.  AB2-200 can achieve maximum flight stability and maximum speed with AeroPoint as well as Aerodynamic design broadhead such as Traumahawk. AB2-200 is offered in lengths from 20 to 26 inches and is built with 0.001" straightness shaft.  The weight of AB2-200 with AeroPoint, AeroInsert, and Hybrid Insert is 325 grain excluding nock and point.  The amazing straight flight of AB2-200 is due to AB2-200 has a variable spine design (as a result of effect of Hybrid Insert System), its spine in the front is 0.060" and at the back is 0.200". As a quality mark of Aerobolt II, they are spine indexed, hand marked with weight, length and manufacture date.

AeroBolt™ II - Dragon Slayer (AB2-DS)
AB2-DS crossbow arrow is the big brother of the AeroBolt II.  AB2-DS is built for African Big Game and is heavy in weight 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.  AB2-DS is offered from 16 to 26 inches; and is engineered to give maximum momentum and penetration power.  Unlike any other crossbow bolts, it has a 0.092" thickness of carbon throughout its entire length.  Unlike AB2-200 which having hybrid system, AB2-DS has two inner shafts that go through most of the length of AB2-DS.  The inner 2 shafts are engineered to be super heavy and super stout.  In addition, AB2-DS comes standard with Firenock AeroInsert-DS (S=Stainless) and are ready to fit Firenock F, D, J, M, Q or V lighted nock as extreme shock end cap is pre-installed.  With this special construction, all components on AB2-DS are supported by inner 2 shafts and the outermost shaft.  For a 26 inches AB2-DS, the expected total weight (excluding point and nock) is about 750 grain (including Aerovane II).  This specification makes AB2-DS the ultimate African big game crossbow shaft.  From our field staff reports, it is also found that it is the best bolt for the huge 700lbs+ wild boars in the lower states such as Georgia and Texas.

The AeroBolt™ II-G (AB2-G)
AB2-G crossbow arrow is also designed for big game, but it is lighter than AB2-DS whilst it is heavier than AB2-200. AB2-G is specially designed to give maximum front end mass and to transfer maximum kinetic energy in order to penetrate deep or pass through the big game animal. To provide even more blunt force, AB2-G fitted with Traumahawk broadhead will give you amazing result and you will be surprised how flat AB2-G with Traumahawk broadhead can fly and how far they can reach.

Features of AeroBolt II-G:

  1. Spin over 2500 rpm with virtually no drag effect
  2. Frontal focus mass is over 200 grain
  3. Super straightness (0.006" or better)
  4. Fitted with Self Concentric AeroPoint 175 grain AeroPoint (10mm wide, 9mm base) as standard / Traumahawk as an option
  5. Equipped with Hybrid Insert System (40+ million modular carbon) for strong reinforced front end, straight and oscillating free flight
  6. Durable high modular carbon outer shaft (33 million modular carbon)
  7. Fitted with Aerovane III for quiet, light weight and no drag Aerodynamic high speed spin
  8. Initial first bend Indexed to achieve repeatable accuracy shot after shot
  9. Weight variation between bolts is within 3 grain to achieve repeatable accuracy

Note: All AeroBolt II are fletched with Aerovane II or Aerovane III vanes.  The standard vane configuration of Aerobolt II is 3 vanes (white, yellow and red). Custom vane color configuration, 2 vanes and 4 vanes are also available, but with extra charge.  You can also order your AeroBolt II without vane.  All Aerovanes on AeroBolt II are fletched with Firenock Aerovane Jig and glued by Aerovane Glue AG0600.  You can also choose material for your AeroInsert: Aluminum (17 grain) or Stainless (50 grain).  Furthermore, you can order Aerobolt II in your prefer weight and length.

The weight and length of standard configuration of AeroBolt II without nock, point and vane are:

  Aerobolt II   Length (in)   AeroInsert   Carbon Inner Tube Length (in)   ~ Weight (gn)
  AB2-200   22   AID22A*   7.5   285
  AB2-200   26   AID22A*   5.5   305
  AB2-G   22   AIH22S   7.5   385
  AB2-G   26   AIH22S   5.5   401
  AB2-DS   22   AID22S   Full Double   625
  AB2-DS   26   AID22S   Full Double   725
*AID22S (S = Stainless) is available as an option.
VIDEO
   If you wonder how loud and what it looks like when one shoots AeroBolt II-200, here is a video provided by a new customer shooting his AeroBolt II-200 at 100 yards under 15 miles breeze and he has shot AeroBolt II-200 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

Information marked on AeroBolt II - 200 label or AeroBolt II Dragon Slayer

AeroBolt II-200 (3-arrow)
AeroBolt II-G (3-arrow)
AeroBolt II-Dragon Slayer (3-arrow)

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?  You will understand and be convinced after reading the below: a short review of research and development of AeroBolt and its design and technologies.  Furthermore, with better understanding of AeroBolt II technologies, you should acquaint what you can expect and what you can achieve the most from shooting with AeroBolt.
    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.  AeroBolt I was first built with 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.  Aerobolt I gave Jim the arrow he needed at that time as this specification gave Aerobolt I a heavier resulting spine and lessened the issue of not locating the spine due to dual shaft construction.  During the test of Aerobolt I, interesting facts were discovered and these leaded us to develop new concepts, break through manufacturing processes, improved design and eventually resulted in 4 US Patents.

Development of never harden 2 part epoxy
    When the AeroBolt I was made, CA base glue was used 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 issue was worst when 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 and became powder leading to layer separation and the failure of CA glue allowed the arrow to flex more and resulted in more cracks.
    A variety of glues, Super Glue, CA GEL, 5 minutes, 10 minutes, and even 30 minutes epoxy were tested, but they all failed.  Through the tests, we found that glue had a higher flexibility after cured, better result could be achieved. These results coincided with the idea that glue failure was due to the flex of the arrow during launch which leaded to carbon layer separation, then resulted in inconsistent of spine and finally ended up with inconsistent arrow flight.
    After repeated testing, a rare, expensive 2 part epoxy was found to be ideal as the epoxy is considerable flexible even it is totally cured.  Furthermore, the epoxy allows close to 2 hours work time, but this epoxy has high cP (i.e. does not flow and spread well).  To encounter high cP while gluing an carbon inner shaft (as long as 13") into the main shaft, usual apply and spread method would not work. Thus a special gluing process was developed to achieve perfect gluing between the 2 shafts.

Development of ultra sound cleaning process
    After extensive testing, Firenock found that high quality glue only works when all components are perfectly clean (no dirt, carbon powder, oil etc).  To clean the components properly, 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 shafts before gluing and assembling.

Development of AeroInsert-D/H
    The inherent issue of using a Gold Tip series 22 insert was observed while we have started to build the AeroBolt.  Gold Tip insert was short and did not have a lot of gluing surface.  The result of small gluing surface caused arrow shaft to crack 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 the issues.  AeroInsert is not just a metal insert, it is a hybrid insert which it is a metal insert inserted into a carbon tube and it has merits such as:

  • 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 arrow shaft.
  • Small run out: As AeroInsert-D end is added with a piece of carbon shaft (i.e. Hybrid Insert), run out would become nearly zero as the long length of hybrid insert would eliminate the run out after the Hybrid Insert is inserted completely into the arrow shaft.  For an example, a 26.25" Aerobolt II for Tac 15, the Hybrid Insert can be 5.5" or up to 13.5".

Development of FACT (Firenock Arrow Concentric Technology)
    After long discussion with archery arrow expert like Randy White, Tim Gillingham, one issue is obvious but always overlooked, it is the issue of concentricity.  Concentricity is not only important in arrows, but in bow as well as between arrow and bow.  On the present market, according to Firenock research, there is not a crossbow arrow or arrow rest that can provide good enough concentricity to ensure accuracy of an arrow.  With AeroInsert D, Firenock believed that issue of insert to shaft concentricity has been addressed.  With AeroPoint / Traumahawk, the concentricity of the field point/broad head to Insert also has been addressed.

Development of Self Harmonic Dampening AeroBolt
    What is Harmonic Dampening? Harmonic Dampening was first observed when AeroBolt I was being tested.  During the test, we observed that the oscillation of AeroBolt I stopped only after about 5-10 feet.  This observation was unusual as a general arrow would usually oscillate at least 20 yards.  In general, 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. not oscillating).  Also from our tests, it was 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.  For Aerobolt, Hybrid Insert changed the above as the spine of arrow shaft changed completely, you will find Aerobolt stop oscillating soon after shot and will fly straighter and more accurate than any other bolts.

Development of Professional Arrow Preparation System (PAPS)
    Locating spine of an arrow is important as it tells you how the arrow will oscillate when it is shot.  In general, most will use the RAM Spine finder machine, however RAM Spine finder machine takes too long to spine index an arrow and it is not reliable.  Thus Firenock built PAPS.  PAPS is a easy to use tool, you can find the softest side of natural spine of an arrow easily within 5 seconds.  We believe the softest side of natural spine is more important than the hardest side as an arrow will flex towards it softest side when it is launched (i.e. an arrow will flex towards the lowest resistance side).  Furthermore, the hardest side only gives an indication of the hardest spine rating which it is not critical for arrow accuracy.  With PAPS, repeatable accurate shooting among a bundle of Aerobolts without tuning is made possible.

Using Aerovane to Lift instead of using drag to spin
    AeroBolt uses Aerovane as its standard vanes.  Aerovane is using Aerodynamics to create spin instead of using drag (typical vanes use drag to cause the arrow to spin).  Due to using drag to spin, a lot of archers prefers to use a much heavier field point and/or broadhead as heavier field point can compensate the drag caused by typical vanes.  With this heavy setting, the front heavier point will be the dominant force to drag down the arrow and the vanes at the back will stabilize the arrow from the drop as vanes force air passing them as well as causing spin.  This also explains why some arrows need heavy FOC (Front of Center) in order to fly right.
    For Aerobolt with 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.

Using Gluing instead of mechanical way to secure insert
    As the front end of the arrow will encounter extreme amount of force and vibration in all unpredictable direction upon impact, mechanical insert will focus the force and vibration upon impact and can damage the shaft inner surface.  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 metal AeroInsert is mated and glued with a long carbon inner tube and then the AeroInsert with carbon inner tube is glued into the arrow to provide large surface area to spread and relief force from impact.

Spine Indexing and Matching
    In order to allow archer to shoot Aerobolt with repeated accuracy, Firenock spine indexed and made Aerobolt within +/- 3 grain to ensure every Aerobolt will behave / shoot the same.


Conclusion

From the above, you should understand why AeroBolt can oscillate less, fly straighter and reach long distance than any other bolts and why Aerobolt can have less FOC as it is using lift instead of drag to spin arrow. In summary, the combination of Self Concentric Technology, Hybrid Insert System and Aerovane make AeroBolt oscillating less, stabilizing itself faster and achieving gyro spin faster than any other bolts. As achieving gyro spin means less energy is lost, maximum amount of energy can be transferred to achieve a flatter, more accurate and more powerful shot.