Tim is having problems with the registration process so asked me to post for him until he gets the problem resolved.
Experimenting With Sinew.
Sinew is useful for keeping short bows from breaking, but is not good at increasing the cast of mid-length and longer wooden bows. This is largely because sinew is lightly strained in such situations, and has high mass.
The idea here is to cause the sinew to be far more strained than typically, making it do far more work per mass. Elevating the sinew well above the bow back would accomplish this by increasing it's percentage of stretch.
This first experiment elevated the sinew by placing a filler of hide glue-soaked cotton string between the back and the sinew. The goal was to see to what degree draw weight could be increased while raising mass by small amounts.
The belly is bamboo, 46" long, weighing 5.5 ounces.
The dry weight of the sinew and glue is about 2 ounces.
Once in place the bow was twice as thick as the bamboo alone.
The bow was held in 5" of reflex when sinewed, holding 6" of just-unbraced reflex.
Draw weight rose 400% of that of the bamboo alone!
Some touch-up tillering is needed, so corrective amounts of sinew will be added in a couple of areas before going to full draw, and a visit to the chronograph. My guess it that it will well outshoot same-draw weight conventionally sinewed wooden bows, and Asiatic composites. We'll see.
Meanwhile, please let me know of other efforts to get more work out of sinew by elevating it above the bow back. And your results, and details, if you do something along these lines yourself.
Arguments, comments and suggestions welcomed.
Tim Baker
