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Liberty Archery Liberty 1 Bow
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Date product posted
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0
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10889
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5/15/2005
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Recommended By
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No recommendations
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None indicated
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Description:
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20.5 Axle to Axle (32" draw bow uses 1/2" longer limbs axle to axle 21.5"
weighs 2.3lbs
Beat bows advertised at 332-340 FPS
85% let off 7 inch Brace Height
DRAW LENGTHS(non adjustable) - 26.35", 26.875", 27.375”, 27.95",
28.45", 28.81", 29.35", 29.9", 30.5", 31.0", 31.57", 32.0"
DRAW WEIGHTS - 40-50#, 50-60#, 60-70#, 70-80# (10lbs adjustable)
HANDLE: Erogometric angle at 29 degrees
STRING: 450 Plus (no stretch) Buss cables are cable, not string. Read below!
CAMO - RealTree Hardwoods High Definition Green
Design History
The original intent was to make a very small light weight complete hunting package. A bow with 4 arrows that I could hook onto my backpack and not even feel it. A complete small bow kit that I could put into the corner of my car trunk. In many ways this goal was met with some 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 surpises was the human energy expenditure, so I will cover it briefly first.
Human Energy: We had Physiological energy 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: 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 the separated limbs make, you have a wide 3 point architecture for the top and bottom set that is very stable. This limb configuration twists the limbs during draw, adding rotational stored energy.
CAMS: 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 to that of other bows and have an extremely fast bow or to keep the low holding weight.Tested against other fast bows (even with the low holding weight) we beat them. A possibly third unexpected result was that for heavy arrows the Liberty I was extremely fast.
Limbs: Are made of carbon composite core laminated with Ultra S on the outside and Bow Tuff on the inside. This combination provides the limb integrity for the amount of bending.
Cables: The manufacturers of 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 getn perfect timing.
If you use a Peep sight: Because the bow is so short the string angle puts the peep far up the string. A special peep was made to accommodate the string angle (3 sizes), which can be purchased with the bow. Or better yet, use a No Peep.
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Guide
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Posts: 548
Registered: January 2004
Location: Plainwell
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