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
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
think it might be the most accurate of all bows and
would not be surprised if it won the prestigious
Vegas tournament one day.
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 archery industry.
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
Mass Weight: Result was 2.52 lbs loaded (sight and
arrow rest) weight. Bow weighs 2.3 lb unloaded.
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.
Design History Update Jan
To get faster bows other bow
makers shortened the limb
travel. To get the draw length
they had to increase the length
of the riser. They know that
SPEED SELLS. What they gave
up is maneuverability through
brush, lighter weight, low
let-off and easy draw curve.
The Liberty Bow got the speed
back with its light and stiff
arrows. The end result is that
the maneuverability (small
size), light weight, high let-off,
and easy draw curve attributes
that has made the Liberty bow
so popular and loved, now has
the greatly admired SPEED.