Cams: Dave Barnsdale of Barnsdale Archery was very instrumental in the cam design. It was Dave that had the idea of spreading the
cables in the cam itself. This was a patentable idea but was not pursued at the time and Martin Archery now holds the patent on that
design, even though Dave Barnsdale had the idea first.
To make a very short bow most of the string must be in the cams. This means that the cams must be quite large. There were two
unexpected results from the prototypes; first, the large cam increased the leverage at full draw greatly decreasing the holding weight,
second, the large cam had amazing speed. Typically, when you have a low holding weight you loose a lot of speed. It was possible to
increase the holding weight equal to that of other bows and have an extremely fast bow or to keep the low holding weight, we chose
the low holding weight. Most important feature is that the cams will never go out of sync. This is due to the steel cables that do
not stretch over time. Tested against other fast bows (even with the low holding weight) we matched them. A possibly third
unexpected result was that for heavy arrows the Liberty I was extremely fast ( I do not know why).
Cam Sizes: It is impossible to make the very best shooting bow from one modular cam. At best you can make a
optimum bow every for 1/2" of draw length. That is what we did, a completely redesigned bow every 1/2". That
meant-22-cam jigs for our CNC (each jig is 16" x 38"). A big expense but we feel it is the only way.
Vibration: Noise took us a long time to solve, We mounted a decibel meter on the Hooter Shooter and compared the Liberty I to
other bows. At first it was very noisy, we tried Limb Savers (no improvement) etc. The end result was that the noise was coming
from 4 places, limb pockets, cable heads, cables, and string.
With a redesign of the cable head, polyurethane pocket cushions, Sims, and Bow Jacks, all was solved. Retesting against our
competitors we were lower on the decibel meter (less noise).
Cables: The manufacturers of synthetic cables cannot make extremely accurate cables. The only solution was to make adjustable
cable heads.With 6-32 threads it means that one turn is 1/32" or .03125". We found that as little as 1/8 of a turn makes a big
difference when setting the timing of the cams. First we adjust the cables so that the cam is not tilted, then we mark the cable head
and turn each head equally to get perfect timing.
Accuracy: Our limb manufacturer Barnsdale Archery's owner Dave Barnsdale happens to be an expert shot.
He has tested the bow and we print his quote again. Dave Barnsdale, Winner of 2005 Vegas Tournament says “ without much
practice I shot a perfect 300 NAFF round (on Liberty I bow)”, “will be hunting this fall with a Liberty”
Accuracy follow-up. Many emails, Warranty Card Comments, phone conversations and field tests have all remarked about the
accuracy of this bow compared to Mathews Switchback, Bowtech Tribuite, and Hoyt Trykon or any other bow. I am beginning to
think it might be the most accurate of all bows and would not be surprised if it won the prestigious Vegas tournament one day.
|Phone (408) 983-1127 Santa Clara, CA
Limbs: Are made of Gordon composite core laminated with Ultra S on the outside and Bow Tuff on the inside by Barnsdale Archery.
This combination provides the limb integrity for the amount of bending. It is well known that Barnsdale limbs are the best in the
Sight: When the bow was first designed the sights were mostly like the Vital Bow Gear sight. Now they are quite different and do
not fit well to make a light weight bow. Only the sight head is used (saves weight). Vital Bow Gear now has a complete sight line
that works with the Liberty I
Arrow Rest: Initially we tried a simple "v" rest, but because of the string angle the arrow would pop off. So total containment rests
are a must: Whisker Biscuit or Hostage are recommended. The best drop away is Tri-Van Vanishing Rest, by Tri-Van.
String: Initially we were using BYC 8125, but on hot days performance (speed) decreased and the sighting was off (used Hooter
Shooter). Switched to Winners Choice pre-stretched strings 7/15/05. Now also Vapor Trail pre-stretched strings as some dealers
prefer them over Winners Choice strings.
Human Energy: We had physiology consultant calculate the energy expended while shooting the Liberty I
as-compared to a lower let-off bow. His result was that shooting a 70 lb Liberty I bow consumed the same
energy as shooting a 60.56 lb competitors bow. Assumptions: 2 sec draw, 5 sec holding time. The benefits
from this are plentiful; you can enjoy the speed and not get tired, spend more time at the range enjoying
your favorite sport, much less hand shake (therefore more accurate), and to hold at full draw longer until
animal is in the clear.
Riser: The basic design was to shoot through the limbs and eliminate the heavy riser. We made a investment cast A357-T6
aluminum riser that is very strong (used for jet impeller blades) and got the riser close to 1/2 lb. With the "A" frame structure that
configuration twists the limbs during draw, adding rotational stored energy.
Peep Sight: Because the bow is so short the string angle puts the peep far up the string and at the wrong angle.
Initially the bow was 18.5" axle to axle, but the peep did not have enough string and wrapped into the cam.
Consequently the cam was modified and the axle to axle increased to 20.5". A special peep was made to
accommodate the string angle (3 sizes). Peep sights can be eliminated by using the Hind Sight-Inc.(734) 878-284
also available from Liberty Archery. Use the no-peep rear sight with the Liberty 3 pin regular sight.
Handle: The handle at first was walnut (which is very light) but for the shape needed, it chipped. Next we tried
solid-Sarlink 3180 (EPDM) and it was very heavy. The final result was to mix the Sarlink with Safoam (light weight
filler)-and to-rib the inside of the handle (increase cushioning and reduce weight) See Right. To keep the cable from
hitting-your-wrist, the handle angle is 29 degrees.
Mass Weight: Result was 2.52 lbs loaded (sight and arrow rest) weight. Bow weighs 2.3 lb unloaded.
Reducing the weight of present day bows was the main reason we made the Liberty I. We toyed with
magnesium, carbon, no limb pockets, walnut handle, and hollow limbs. The greatest weight reduction was
the shooting between and limbs and elimination of the sight bar.. We incorporated the sight bar extension
into the riser, something the other bow manufacturers can't do. When you add up the 3.5" sight bar, the
attachment brackets on both ends (one to sight, the other to the bow) you eliminate about 1/3rd of a pound.
We researched all sights on the market and picked the lightest and strongest. The Whisker Biscuit or Hostage
model were chosen for their weight and semi-nonadjustability as they should be left at the factory setting.
We suggest the"Catquiver" by Rancho Safari for walking around, and a detachable one for tree stands.
I wanted a small lethal package. Three arrows and bow small enough to fit in the corner
of my car trunk. In many ways the goal was met with positive surprises along the way. I
will go through the various parts of the design and how they satisfy this goal. One of the
most enjoyable surprises was the human energy expenditure, so I will cover it first.