[Ansteorra] catapulting

[robert segrest]

When I was in Scouts we used to compete at making
'ballistas' out of staves {broom handles).  It was an
excercise in lashing, so the design was the same for
all of them.  All poles were 5 foot long ash staves
(again, broom handles).  The base is a tripod of three
staves, with three more staves used to brace across
the bases (thus forming a trigonal pyramid for you
geometers).  The arm is three poles lashed parallel,
such that one pole is between the other two, and they
overlap for about a third of their length.  This makes
for an arm 7-8 feet long.  Attach a #10 can (what
commercial vegetables come in, or used to.  I bet the
cafeteria throws away dozens of them) to the single
pole end, and two ropes to the other end.  The double
pole end of the arm sits in the crotch of the tripod,
the ropes run under the cross brace on the front face,
and back on either side of the arm.  Put a water
balloon in the can, pull the ropes, viola, something
like a catapult.  It takes some practice to get any
accuracy, since the ropes have to be pulled fairly
evenly, but it is within the power of ten year olds to
do it.  Best of all, it is difficult for them to hurt
themselves with it (although not impossible unless
they have improved the design of ten year olds recently).

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