1M40.99 - Onager
Wind up the strings on the onager being careful that you wind both sides equally and in the right direction. These will have to be wound very tightly for this to work well. Place a Ping Pong ball into the spoon, pull the arm back and set the trigger. Release the trigger and the ball should travel about 20 feet.
- Mark Denny, "Optimum Onager: The Classical Mechanics of a Classical Siege Engine", TPT, Vol. 47, # 9, December 2009, p. 574.
- Kelvin Catapult Design P/N 841860, Kelvin School Projects.
- Philip Friedman, "Tool Test", Pop Mechanics, Aug. 2012, p. 97.
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