Atlatl dynamics

Summary

J. Whittaker: Video digitizer and mathematical model used to predict velocity of darts under given conditions. - horizontal force, wrist torque, mass of hand, radius of gyration, weight of dart, length of atlatl. Simpler model than Cotterell and Kamminga 1989.

Hand-thrown dart has short lever action (hand+wrist) while atlatl is much longer lever.

Conclusions: Atlatl length (between .3-.75m) has little effect on velocity, although optimum length was .45 m. Adding a weight to atlatl can increase velocity up to 2.7%, but if atlatl at optimum length, always loses velocity. Heavy darts do better with short atlatls. Hand thrown dart (2 different weights) has 62-75% kinetic energy of same thrown by atlatl. Flexible atlatl transfers more energy to dart - their atlatl stored ca. 6.9% of dart's kinetic energy - more flex would be even better. Dart flex contributes little energy to forward motion, is mostly vibrational, but important in getting straight throw despite curving motion of atlatl. [Are differences of 3-7% real or random? I am dubious about effects of both atlatl weights and flex, but he’s right that dart flex adds little energy. I have trouble understanding his explanations of physics.]

This Resource is Part of the Following Collections

• EXARC Experimental Archaeology Collection

Keywords

Individual & Institutional Roles

Contact(s): EXARC Experimental Archaeology Collection Manager

Record Identifiers

ExArc Id(s): 9900

Notes

Rights & Attribution: The information in this record was originally compiled by Dr. Roeland Paardekooper, EXARC Director.