Look, I get what a pain it must be to try and read this blog and figure out what exactly this experiment is that I keep beating on about.  In the next few paragraphs I will try to abbreviate the process into as few a words as possible in the hope it may act as a signpost amid this terrifying clutter of verbiage.

Given that square crossbars, even those with a small corner radius, are quite damaging to the spring cord in high-power machines, why are there original crossbars that have a square cross section?

Answer: either the ancient machines were very low powered (not at all likely), or the Romans loved replacing their ballista springs every couple of hundred shots, or ……… wait for it ……… the square crossbars were likely part of some kind of wedge machine because wedge machines require square crossbars for their wedges to push against.  (If you understand the mechanics of a wedge machine,  this latter is self evident.)

The experiment with Phoenix will determine if it is possible to create high-power (say 1200 foot lbs or more, 350+ fps) and good balance with a wedge type system similar to the one described by Philon.

If the attempt is successful, it will not only suggest a reason why there were square crossbars, but also show it is possible to balance a torsion engine with a technique completely independent of washer rotation.  This is important because it will provide a rationale for the unaccountably low number of washer locking holes on certain artifacts (e.g. the Lyon machine).

So, in short, that’s what all the fuss is about.

 

 

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