Ecocomposite: Sinew-backed Bows
By David A. Bainbridge
Associate Professor
United States International College of Business
Alliant International University
San Diego, CA 92131
There are typically two or three layers in sinew backed bows: sinew on the
back (the side under tension away from the archer), wood, and in some
cases, horn on the belly (the side under compression). These are widely
known around the world from many cultures and times.
Sinew and horn are added to the wooden bow to make it more effective.
Sinew or tendon is largely collagen with a resilience of 93%, better than
rubber. When it is stretched and released only 7% of the energy is lost.
That is very good, but collagen is twenty times better than spring steel
at energy storage and return in relation to weight. Only one natural
material exceeds this achievement, resulin, the spring that makes insect
wing beats possible. Resulin provides 97% energy return when stretched and
released. This reduces heat gain more than 50% compared to collagen (7% to
3%).
"The bows are not more than two feet and a half in length, they
are formed of a slip of red cedar; the grain being on one side untouched
with any tool, while the other is secured with sinews attached to it by a
kind of glue. Though this weapon has a very slender appearance, it throws
an arrow with great force and to a considerable distance."
Alexander McKenzie on the Bella Coola River, British
Columbia 1793.
The use of tendon fibers dramatically improved the cast of short (1 meter
or less) bows. (For sources of tendon see Primitive
Archer.) Horn on the belly side added additional cast. Sinew backed
bows have lofted arrows more than 600 meters (yards) in the U.S. and
Turkish sinew and horn flight bows have reached over 820 meters (900
yards).
Sinew was chosen from animals specifically for bow use, some suggest that
leg tendons from wild animals were preferred. The tendons were pounded and
fibers were selected, matched and carefully oriented on the bow. The
preferred glue was often fish air bladder (isinglass), but hide glue was
also used. These glues could be very flexible and strong if made
correctly. Several layers of tendon fibers were added. These bows were
affected by water and even high humidity so the bows were kept as dry as
possible. Paints were used to help keep them dry.
Further Information:
Excellent Video (Hard to get -- A retail
source for consumers is needed.)
Sinew-backed Bow and its Arrows. FCA 1207. Department of Anthropology,
University of California, 1961. 24 min., color,
16mm, 1 reel. From the
University of California American Indian Film
Series.
The film follows in detail the construction of a
sinew-backed bow--the finest and strongest of the bows used by American
Indians--by a Yurok craftsman.
For educational use and wealthy enthusiasts order through cmil@uclink.berkeley.edu.
Catalog #37140. Sale: video: $150: Rental: $50.
Karpowicz, A., J. James and A.B. Kim. Nd. Asian and Turkish Bow
Construction.
http://www.dellarco.com/ontarget/bodies/turk.html.
NorthernLight 01/08/01.
Adam Karpowicz - akarpowicz@mta.ca
Hamm, Jim. 1992. Bows and Arrows of the Native Americans. Lyons Press.
160 p.
ISBN 1-55821-168-3. $14.95.
Primitive Archer Magazine. http://www.primitivearcher.com/pages/contact.html.
Journal of the Society of Archer-Antiquaries.
Wyley. S.F. Nd. A Bibliography of Archery.
http://toffee.snt.utwente.nl/campus/sagi/artikel/misc/bibliography.html.
NorthernLight 01/08/2001.
Bibliography of composite bow construction. http://rustam.uwp.edu/biblio.html.
Lake, F. and H. Wright. 1974. Bibliography of Archery. Simon Archery
Foundation.
http://www.museum.man.ac.uk/collections/archery/archery.html.
Klopsteg, P. 1947 [1934]. Turkish Archery and the Composite Bow.
Self-published. Translation (with additions) of
an article by Joachim Hein,
"Bowyery and the Sport of Archery among the
Osmanli" in Der Islam, 1925,
which in turn is a translation of an Arabic text
by Mustafa Kani, "Excerpts
from the Writings of the Archers," 1847.
Excerpts on line at http://www.dellarco.com/ontarget/bodies/turk.html.
T'an Tan-Chiung. 1951. Investigative Report on Bow and Arrow
Manufacture in
Chengtu. Academia Sinica, Taiwan. Reprinted in
Soochow University Journal
of Chinese Art History, July 1981.
McLeod, W. 1970. Composite bows from the tomb of Tut'ankhamun. Griffith
Institute at the University Press by V. Ridler.
40 p. Series title:
Tut'ankhamun's tomb series. Hickman, C. N.
1959. Ancient Composite Bows. Journal of the Society of
Archer-Antiquaries. Volume 2.
http://snt.student.utwente.nl/~sagi/artikel/ancient_composites/
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