I am waiting for ten backstraps of elk sinew to show up.  They are each a couple of feet long, and there should be enough sinew in them to make a torsion spring of, maybe, 1″ in diameter by 9″ long.  In any event,  the pair of small mangonels  that we are going to build will be sized by whatever we come up with for a small, prototype, sinew torsion spring.  The models will be considered simple test beds to discover the propulsion ratio between nylon and sinew.  They will have no historical authenticity attached to them and will be built to close enough tolerances (+/- .005″ all dims, should do it)  that mechanical consistency between the two machines will be assured.

There will be no need to complicate the experiment by fitting these one armed machines with a sling.  We’ll use a simple spoon type arm ala Monty Python,  and match the two machines in tuning as closely as possible.  Our only intent will be to find, as simply as possible, the comparative power of a sinew spring vs. a nylon one.  Naturally, both springs would need to be of the same size and have the same draw length and draw weight.  How far our two differently powered models will toss a particular sized steel ball, should give us a ratio with which we can predict how well a full-sized reconstruction equipped with nylon springs would perform if it was powered by good old-fashioned sinew.

This seems to be the only practical way to get a fix on what Firefly would be capable of if she was powered by authentic materials.  I did some rough calculations on the cost of enough raw sinew to make full sized springs for her.  The material alone would be over $10,000,   not forgetting the Herculean effort needed to process it into usable cordage. —  And with springs that precious it would be a dire moral challenge to take them near enough to their breaking point,  just to model the upper limit of  their performance. — So much better to explore this matter with smaller scale models where one can afford to challenge the Gods a mite, and have a failure or two to help peg the envelope.

Besides,  springs are just springs, and data describes them all.  Valid extrapolations are more useful than impractical fantasies of perfection that never come to fruition.

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